Inspection of air conditioning systems. Engineering a sustainable built environment

Transcription

1 Inspection of air conditioning systems Engineering a sustainable built environment TM44: 2007

2 Inspection of air conditioning systems CIBSE TM44: 2007 ACRIB Engineering a sustainable built environment The Chartered Institution of Building Services Engineers 222 Balham High Road, London SW12 9BS

3 The rights of publication or translation are reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means without the prior permission of the Institution. June 2007 The Chartered Institution of Building Services Engineers London Registered charity number ISBN: This document is based on the best knowledge available at the time of publication. However no responsibility of any kind for any injury, death, loss, damage or delay however caused resulting from the use of these recommendations can be accepted by the Chartered Institution of Building Services Engineers, the authors or others involved in its publication. In adopting these recommendations for use each adopter by doing so agrees to accept full responsibility for any personal injury, death, loss, damage or delay arising out of or in connection with their use by or on behalf of such adopter irrespective of the cause or reason therefore and agrees to defend, indemnify and hold harmless the Chartered Institution of Building Services Engineers, the authors and others involved in their publication from any and all liability arising out of or in connection with such use as aforesaid and irrespective of any negligence on the part of those indemnified. Typeset by CIBSE Publications Printed in Great Britain by Page Bros. (Norwich) Ltd., Norwich, Norfolk NR6 6SA Cover illustration: TEK IMAGE/SCIENCE PHOTO LIBRARY Note from the publisher This publication is primarily intended to provide guidance to those responsible for the design, installation, commissioning, operation and maintenance of building services. It is not intended to be exhaustive or definitive and it will be necessary for users of the guidance given to exercise their own professional judgement when deciding whether to abide by or depart from it. Printed on 100% recycled paper comprising at least 80% post-consumer waste

4 Foreword On 4 January 2003 the European Parliament and the Council of the European Union published Directive 2002/91/EC on the Energy Performance of Buildings (EPBD). This requires Member States to bring into force the necessary laws, regulations and administrative provisions to comply with the Directive. Article 9 requires Member States to introduce measures to establish a regular inspection of air conditioning systems. In England and Wales the Energy Performance of Buildings (Certificates and Inspections) (England and Wales) Regulations 2007 implement Articles 7 9 of the Directive. They require inspection of all air conditioning systems with rated outputs over 12 kw at intervals not greater than 5 years. An Industry Working Group comprising ACRIB, BRE, BSRIA, CIBSE, FETA, HVCA, IoR and Summit Skills has developed this document to give guidance on meeting these regulations. TM44 provides guidance on carrying out the required inspections within reasonable constraints of time, cost and skills, including specific guidance on generating advice for the user, on a consistent basis. Engineers and energy managers responsible for these systems need to consider how they will comply with the new rules. For systems over 250 kw they have until January 2009 to complete the first inspections, and for the remaining systems over 12 kw they have until January Building owners and managers wishing to understand the purpose and scope of the inspection should read at least the introductory section 1 and the explanatory section 6. These provide an overview of the inspection, and its potential benefits and subsequent use, to help managers prepare for the visit and to consider what further actions may be appropriate after the inspection. Those wishing to carry out the inspection should read at least sections 1 to 5 as relevant to the types of systems they will assess. Other parts of the EPBD, and of the Energy Performance of Buildings (Certificates and Inspections) (England and Wales) Regulations 2007, include a requirement for a certificate describing the energy efficiency of the whole building to be prepared and made available on sale or rent of buildings. This certification process will also involve the inspection of buildings to obtain basic details of the building fabric, building services (heating, lighting and air conditioning systems) and other equipment used in the building. European Regulation (EC) 842/2006, the F-Gas Regulation, which comes into force 4 July 2007, requires regular inspections of some refrigeration systems to test for leakage of fluorinated greenhouse gas refrigerant from systems. Some refrigeration systems containing CFC or HCFC refrigerants may already be subject to regular leakage testing under European Regulation (EC) 2037/2000 on substances that deplete the ozone layer. And some air conditioning systems will fall under the scope of the Pressure Systems Safety Regulations 2000, which may apply to systems with an installed power in excess of 25 kw. TM44 also indicates how building owners and managers should be advised to prepare and keep information from all these inspections so that the time needed to carry them out, and hence their cost, can be minimised. The group advising on the preparation of this document also provided input on behalf of the UK to the Working Groups of CEN TC156 developing European Standards for air conditioning and ventilation system inspection to support the requirements of the EPBD. Hywel Davies Chairman, TM44 Working Group Principal author Peter Grigg (BRE) TM44 Working Group The Working Group comprised the following members, including representatives drawn from ACRIB, BRE, BSRIA, CIBSE, DCLG, FETA, HVCA, IoR and Summit Skills. John Armstrong (consultant) Derrick Braham (CIBSE) Darren Bryant (Efficient Air Ltd.)

5 Colin Biggs (Nuaire Ltd.) Geoffrey Brundrett (consultant) Hywel Davies (CIBSE Research Manager) (Chairman) Paul DeCort (Department of Communities and Local Government) Terry Dix (Arup) Mike Duggan (FETA Technical Manager) Alan Green (Trox UK Ltd./CEN TC156) Peter Grigg (BRE) Malcolm Horlick (Air Conditioning and Refrigeration Industry Board) Steve Irving (FaberMaunsell) Michael Reeves (Summit Skills) Mike Smith (BSRIA Ltd.) Bob Towse (HVCA) Acknowledgements The Institution acknowledges the support of the Department of Communities and Local Government for funding the principal author in preparing the document and participating in the work of CEN TC156 WG10, which is developing European Standard EN 15420: Inspection of air conditioning systems. The Institution also acknowledges the contribution of Graham Manly (Gratte Brothers) in the production of this guidance. Editor Ken Butcher CIBSE Research Manager Hywel Davies CIBSE Publishing Manager Jacqueline Balian

6 Contents 1 Introduction 1.1 Background 1.2 Scope of the inspection required by the EPD Regulations 1.3 Factors affecting air conditioning system efficiency 1.4 Provision of advice 1.5 Preparation for the inspection 1.6 Energy consumption metering 1.7 Extent of the inspection 1.8 Guidance on good practice inspection and maintenance 1.9 Appropriate forms of inspection procedure 2 Inspection of packaged cooling systems 2.1 Checklist of pre-inspection information 2.2 Inspection process for packaged systems 2.3 Reporting 2.4 Inspection checklist 3 Inspection of centralised systems 3.1 Checklist of pre-inspection information 3.2 Inspection process for centralised systems 3.3 Reporting 3.4 Inspection checklists 4 Assessing equipment sizing in relation to the cooling load 4.1 Estimating loads for packaged systems 4.2 Estimating loads for larger installations 4.3 Assessment of cooling capacity 4.4 Assessment of ventilation performance 5 Advice and alternative solutions 5.1 Introduction 5.2 Cooling load reduction 5.3 Alternative cooling techniques 6 Explanatory notes for building owners and managers 6.1 Background 6.2 The inspection process 6.3 The inspection report 6.4 Exchanging information with other inspection or certification procedures 6.5 The scope of the inspection 6.6 Good practice inspection and maintenance of air conditioning equipment References Appendix A1: Suggested reporting format for a packaged cooling system

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8 1 Inspection of air conditioning systems 1 Introduction 1.1 Background In England and Wales, Part 5 of the Energy Performance of Buildings (Certificates and Inspections) (England and Wales) Regulations 2007 (1) (known herein as the EPB Regulations ) implement Article 9 of the Energy Performance of Buildings Directive (EPBD) (2). They require regular inspection of all air conditioning systems with rated outputs over 12 kw at intervals not greater than 5 years. This TM gives guidance on meeting the requirements set out in the regulations, including practical inspection procedures for air conditioning systems, and guidance on how to assess efficiency and sizing of the air conditioning system compared to the cooling requirements of the building. It also discusses the advice that is also to be provided to the users on possible improvement or replacement of the air conditioning system and on alternative solutions. The guidance given is consistent with the principles for inspection of air conditioning systems set out in EN 15240: Ventilation for buildings. Energy performance of buildings. Guidelines for inspection of air-conditioning systems (3). The EPB Regulations define an air-conditioning system as: a combination of all the components required to provide a form of air treatment in which the temperature is controlled or can be lowered, and includes systems which combine such air treatment with the control of ventilation, humidity and air cleanliness. For simplicity, the term air conditioning system is used in this document to represent any of the systems described as above, and includes any associated water and air distribution, exhaust, heat recovery and humidification systems that form part of the system. It also includes the controls that regulate these systems. It excludes mechanical ventilation systems that provide no mechanical cooling and any components that are only intended to provide heating that might be contained in the systems. The inspection described in this document is therefore intended to include all types of comfort cooling and air conditioning systems above the specified 12 kw rated output, which is in turn taken to mean the rated cooling capacity of the included refrigeration system. Buildings constructed subsequent to the Building Regulations Approved Document L2 (2002) (4) should have a number of information sources that will benefit and improve the process of inspection. These should include the installation of energy sub-meters to the main air conditioning system components* (5), and the provision of * Guidance is available in CIBSE TM39: Building energy metering (4). a building log book containing simplified descriptions of the air conditioning system, the locations and specifications of its components, and details of its method of control (6,7). In these cases the building owner or manager should have completed records of energy consumed by the major plant, at least on a monthly basis. However, a majority of buildings will not yet have this information, so the assessment of likely energy efficiency described in this document is broad-based and uses indicators from a variety of the most accessible sources. The inspection is primarily based on visual observations and non-invasive measurements where there are opportunities for these to be readily undertaken. 1.2 Scope of the inspection required by the EPB Regulations The aim of the inspection The primary aim of the inspection is to give building owners and operators information about the performance of their buildings and plant, and to identify opportunities to save energy and cut operating costs. The inspection should as far as possible be carried out by making visual observations of the plant and other visual indicators such as refrigerant sight glasses, pressure, temperature or filter gauges, although where these are not available the inspector may be able to take some test readings Health and safety issues Inspectors have a duty to comply with relevant health and safety legislation. This includes a duty to draw the building owner or manager s attention to obvious instances of inadequate maintenance or neglect, where these might have implications for the health and safety of building occupants or the public. This document cannot list potential instances but the inspector should ensure that he or she is familiar with current guidance concerning the health and safety implications of owning and maintaining air conditioning systems, and should seek to satisfy him/herself that adequate precautions and maintenance practices have been taken by the owner or manager to minimise such risks. The inspector s report, while stressing the aim of the inspection in addressing energy issues, should draw to the attention of the owner or manager to any such issues about which the inspector is concerned or is unsure. Suitable formats are described in CIBSE TM31: Building log book toolkit (5) and advice on the use of the log book is provided in GPG348: Building log books a users guide (6).

9 2 Inspection of air conditioning systems Assessment of efficiency Obtaining a good estimate of air conditioning efficiency can be a very complex process involving a considerable investment in time, equipment and expertise. The assessment described in this document is intended to provide a broad view of the design and operation of the system without putting a numerical value on the performance. It addresses areas in which efficiency could be compromised from the design intent, or where aspects of the system could be improved. It also includes guidance on preparing the views required by the EPB Regulations (1) on the size of the system compared with the cooling load and on alternative solutions. The assessment is based on observations and inspections concerning a number of key factors Types of air conditioning systems Air conditioning systems with rated cooling outputs over 12 kw could comprise: Centralised systems: in which refrigeration equipment delivers cooling through air handling unit(s) and/or pumped water circuits. These may include constant volume (CV) systems, variable air volume (VAV) systems, systems using fan coil units (FCUs) or induction units, and systems using active or passive chilled beams. Individual split systems: in which a single outdoor unit containing refrigeration and heat rejection equipment is connected to an individual indoor unit delivering cooling. These may also be called split package units. Multi-split systems: in which one or more outdoor units containing refrigeration and heat rejection equipment are each connected to a number of indoor units delivering cooling. These may also be called multi-split package units, and include variable refrigerant flow (VRF) systems. The indoor part of these systems may be called an indoor unit, or cassette. Distributed heat pump systems: in which a series of individual reversible heat pumps in the treated spaces are linked by a common water circuit to a central boiler and to heat rejection plant. Such systems may commonly be called versatemp-type systems following the trade name of the original patent holder, but there are other systems that operate to the same principle. The rated cooling output of an air conditioning system could also exceed 12 kw where a number of individual units of less than 12 kw rated cooling output are installed to provide distributed cooling within the building under the operator s demise, irrespective of whether or not the individual units are linked to a common control system. Low capacity packaged units such as through the wall units may therefore need to be assessed where the total cooling capacity in the building exceeds 12 kw. The cooling systems may be part of, or used in combination with, other mechanical systems to provide ventilation air to, and/or extract air from, the treated spaces. The inspection procedure and extent of the report to be provided will depend on the type of system installed, see section Factors affecting air conditioning system efficiency The operating efficiency of an air conditioning system depends on a number of factors concerning: the inherent efficiency of the system its state of maintenance, and its effective control. The inherent efficiency of the system is affected by the efficiencies of: the refrigeration equipment that removes heat the refrigerant fluid chosen, and its charge in the system heat rejection to atmosphere the delivery of cooled air or water to, or other means of absorbing heat from, the treated spaces any associated ventilation air supply and/or extract system. As the efficiencies of some air conditioning system components can be reduced at light loads, depending on the type of equipment, method of control used and other issues, the size of the system in relation to the building cooling load can be an additional contributing factor. 1.4 Provision of advice The EPB Regulations require the provision of advice, but does not impose any requirement on the system owner or manager to act on that advice. The benefit of the inspection to the manager would be the provision of appropriate advice on possible improvement or replacement of the air conditioning systems and on alternative solutions that would increase efficiency and reduce energy consumption. For advice to have any real potential to be adopted on a voluntary basis, it should indicate improvement options that are cost-effective over a relatively short period, or are otherwise evidently needed for the system to work effectively. Advice based on this assessment is not expected to involve detailed consideration of the individual system component costs or their use in the particular building, or detailed cost benefit analysis. However, where less immediately apparent opportunities for improvement are identified as a result of this inspection, the advice provided will include the recommendation for the potential costs and benefits to be examined in more detail. 1.5 Preparation for the inspection In some buildings, but by no means all, there will be useful records of the air conditioning equipment installed, its maintenance, and its energy consumption. In more recent buildings these may be found fairly easily where a suitable building log book has been provided in accor-

10 Introduction 3 dance with guidance that first appeared in Building Regulations Approved Document L2 (April 2002) (4). Most larger buildings should have details, including commissioning results, included in building log books, operation and maintenance (O&M) manuals and health and safety (H&S) files, and records of maintenance may be held separately. However in many buildings written records may be incomplete or missing. The information required for the inspection is listed in section 2.1 for simpler packaged equipment and section 3.1 for central systems. The building owner or manager should be advised to make such information available at the time of the inspection. Some observations, such as the use of a smoke pencil to observe air flows, may need the formal approval of the owner or manager and, if considered necessary, isolation of any fire detection systems. A method statement should be provided for the owner or manager to agree prior to the inspection taking place. This should explicitly agree cooperation in providing safe access to equipment as needed, at a mutually convenient time, and approve the use of such simple, non-hazardous, techniques. provides guidance on developing a metering plan and would help in preparing this advice. 1.7 Extent of the inspection Time required to undertake the inspection The time taken for the inspection will depend on the extent of the systems installed. Where the only system is a simple 12 kw split packaged unit, the process should take only a couple of hours. Although the checks suggested here are intended to be fairly minimal, it is doubtful whether a larger system that includes indoor and outdoor cooling plant, AHUs and zone controls could be completed in much less than a day, and substantial installations could take longer. Some of the tasks (e.g. examining inside AHUs or ducts) would probably need to be undertaken outside normal working hours, and must be carried out in collaboration with the building owner or manager, and be subject to a proper risk assessment. 1.6 Energy consumption metering Energy input meters or hours run meters may have been installed to air conditioning systems, particularly to larger individual items of plant. For more recent buildings, this may have been carried out to comply with the guidance of Building Regulations Approved Document L2. Regularly noting the readings of such meters can help assess the operation of the air conditioning system, and could also be helpful to the wider process of assessment that would be needed to provide the building certification required by the EPB Regulations (1). CIBSE TM31: Building log book toolkit (6), CIBSE Guide F: Energy efficiency in buildings (8), and CIBSE TM22: Energy assessment and reporting method (9) include guidance on recording meter readings, and on their interpretation. Where energy consumption has been recorded on a regular annual basis it may be possible to deduce, from the rated input power and the annual consumption record, whether equipment has been in use for excessively long periods. Where more frequent records are available these may allow the onset and end of the cooling season to be identified and compared with expectation. Such simple checks may help to identify whether controls are adequate and have been used appropriately. Where meters are installed, but no consumption records are available, the inspection process should include taking and recording any relevant meter readings, together with the time and date of the reading. This information should be provided to the building owner or manager, to be kept available for the next inspection. The owner or manager should also be advised to continue to take and record meter readings on a regular basis. Where no such metering is in place, a part of the advice provided to the building owner or manager would be to review the scope to install appropriate metering at least to the more significant energy consuming air conditioning plant, and subsequently to record the consumption on a regular basis. CIBSE TM39: Building energy metering (5) Sampling Where an installation consists of a series of individual or multi-split units, inspection of equipment should be undertaken on a randomly selected sample of units equating to approximately 10% of the total, with a minimum of three units. If observations are inconclusive, a further two units should be inspected. Where the air conditioning system includes large numbers of similar units such as VAV terminals, fan coil units or active chilled beams, or the individual room heat pumps of a versatemp-type system, and where no evidence can be provided that these have been adequately cleaned and maintained, then the inspector should examine a small sample. The sample might be one in fifty in installations where there are over a hundred individual units, or just one or two in smaller installations, but the number examined should be sufficient to obtain an indication of the state of maintenance of the units. This will ensure that the inspection can be achieved in a reasonable timescale, and minimise any potential disruption to the treated spaces Recognition of existing inspection and maintenance regimes Where there is clear evidence that a good practice programme of inspection and maintenance is being carried out, then certain aspects of the inspection could be simplified or reduced. In particular those aspects concerned with observing filter or heat exchanger blockage should be addressed adequately by good practice maintenance. However, even though such maintenance should include observations to test for refrigerant leakage, it would still be worthwhile including the relevant observations described here as leakage may begin at any time and the inspection provides an additional opportunity for its early identification.

11 4 Inspection of air conditioning systems 1.8 Guidance on good practice inspection and maintenance One outcome of the inspection will be to prepare advice for the owner or manager on how to improve the performance or the maintenance of the system(s) inspected. A standard part of that advice should be to recommend, where it is lacking, the adoption of a schedule of good practice inspection and maintenance. This may involve more frequent routine inspection than is required to satisfy the requirement of Part 5 of the EPB Regulations (1), as part of an industry good practice maintenance regime. The needs for regular maintenance may not be apparent to some users, and some may not be aware of the consequences of failure to maintain systems adequately, or of their responsibilities as owners of systems. This is more likely to be the case where systems are used in non-critical applications, and where the owner has less experience of the principles and equipment used to provide air conditioned environments. From July 2007 the F-Gas Regulation (10) requires regular testing for leakage of fluorinated greenhouse gas refrigerant from some systems. Some refrigeration systems containing CFC or HCFC refrigerant may already be subject to regular leakage testing under Regulation (EC) 2037/2000 (11) on substances that deplete the ozone layer. Some air conditioning installations fall under the scope of the Pressure Systems Safety Regulations 2000 (12), which may apply to systems with an input power in excess of 25 kw. In these cases it would be appropriate to combine visits or inspections for these various purposes as long as the person (or persons) undertaking the work are suitably qualified to perform all the required functions under each requirement. 1.9 Appropriate forms of inspection procedure Two forms of inspection procedure are described in this document: a simple procedure generally considered suitable for packaged, split and multi-split systems a full procedure that would be appropriate usually where systems are centralised and make use of plant rooms, air handlers, water circuits and more complex controls. The following sections indicate where each of the above would be appropriate Packaged cooling systems (simple procedure) The procedure (see section 2) would generally be applied where cooling is provided in conditioned spaces using indoor units that contain refrigerant-to-air heat exchangers and an integral air circulation fan. These may be either integral with outdoor units that contain the refrigerant compressor, refrigerant to outdoor air heat exchanger and air circulation fan, or connected to the outdoor units by refrigerant pipework. These systems are usually described as follows: Unitary packaged units: the indoor and outdoor units are both contained in a self-contained unitary housing, often installed as a through the wall unit. The unit may be reversible allowing operation as a heat pump, or electric resistance heating may be included. Split packaged units: a single indoor unit is connected by refrigerant pipework to a single outdoor unit. The indoor unit may be floor, wall or ceiling mounted. The unit may be reversible allowing operation as a heat pump, or electric resistance heating may be included. Multi-split packaged units: a number of indoor units are connected to a common outdoor unit by their own dedicated refrigerant pipework. The indoor units may be floor, wall or ceiling mounted. The system may be reversible allowing operation of all the indoor units as heaters in heat pump mode, or electric resistance heating may be included. Variable refrigerant flow (VRF) systems: a number of indoor units are connected to a common outdoor unit by refrigerant pipework on a common network. The indoor units may be floor, wall or ceiling or mounted. Each indoor unit may operate to provide either cooling or heating, allowing heat transfer between zones that require cooling and those that require heating, with the outdoor unit operating in heat rejection or heat pump mode as necessary. Such packaged units or systems usually include selfcontained on-board controls for temperature, and may include a timer control function Supplementary procedure for complex/integrated packaged systems While inspection of installations that contain numbers of multi-split or VRF systems should be relatively straightforward, there may be instances where the application of extensive VRF systems using many indoor units and several outdoor units, with interlinked controls, requires further skill to assess. If such systems are not well documented, including descriptions of the way in which the systems are connected and controlled, an inspector familiar with the simpler systems may wish to draw on further expertise to help assess whether systems have been installed and controlled effectively and where there may be opportunities for improvement. In such cases aspects of the full procedure for centralised systems, described in section 3, may be appropriate Centralised cooling systems (full procedure) The full procedure (see section 3) would apply to more extensive and more complex systems that are generally characterised by the use of water or air distribution systems to deliver cooling to conditioned spaces using a variety of active (i.e. contain air moving fans) or passive terminal devices. They generally include more complex

12 Introduction 5 Assessment type Delivery terminals System type Air handling Refrigeration equipment Heat rejection equipment Unitary packaged ( through the wall ) units indoor and outdoor equipment housed in single casing Single split packaged Outdoor unit to single indoor unit Packaged cooling systems Indoor units/cassettes Multi-split packaged Outdoor unit to multiple indoor units Variable refrigerant flow (VRF) Outdoor unit to multiple indoor units via manifold Multiple linked (VRF) Grilles, slots, diffusers Distributed cooled air only AHU plus refrigerant-to-air heat exchanger Refrigeration plant delivering cold refrigerant Air cooled condenser VAV boxes Centralised systems Induction units Fan coil units Distributed cooled air with terminal cooling AHU plus water-to-air heat exchanger Refrigeration plant delivering cold water Dry air cooler, cooling tower or adiabatic cooler Chilled ceilings and beams Room heat pump Distributed chilled water to terminals only Temperate water loop to local reversible heat pump No cooling in AHU Packaged air cooled chiller supplying cold water Figure 1.1 Summary of system types and their component parts controls that may divide the conditioned spaces into zones where different control parameters can be applied, and that could be located remotely from the equipment, or incorporated into a building management system (BMS). Figure 1.1 illustrates the types of component likely to be included in each type of system, to help decide which form of inspection would be appropriate. Centralised systems include the following: Centralised air systems: cooled air is produced by a cooling heat exchanger in an air handling unit (AHU) and distributed to conditioned spaces through ductwork to grilles or diffusers, or to other terminal units, in the conditioned spaces. The cooled air distribution systems may also include floor or ceiling plena. This category includes systems where air distributed through a centralised ducted system may also

13 6 Inspection of air conditioning systems be cooled at active or passive terminal devices in the conditioned spaces. This cooling may be provided by the indoor units of split packaged and VRF systems where these are installed within the air distribution ducts. Centralised cooled water systems: cooled water is produced centrally and distributed to active or passive terminal devices in the conditioned spaces. Active terminal units would include fan coil units, and fan assisted chilled beams. Passive units would include chilled beams (without fans) and chilled ceiling panels. Terminal units may transfer cooling to recirculated room air, to fresh air drawn locally from outdoors, or to air supplied through centralised ducted systems. Water loop/reversible heat pump systems: systems with individual reversible water to air heat pumps in the treated space that draw or return heat from or to a common temperature controlled water loop (sometimes known as versatemp-type ). Excess heat in the water loop is dissipated as necessary by a cooling tower (often a dry cooler), and an overall requirement for heat in the loop similarly provided by a central heat generator (fossil fuel boiler, electric flow boiler, or other central hat exchanger). Additional systems: some areas may be served by packaged, split and multi-split packaged comfort cooling equipment, including variable refrigerant flow (VRF) equipment. Table 2.1 Packaged systems: checklist of pre-inspection information Level Essential Desirable Optional Information required Itemised list of installed packaged cooling systems including product makes, models and identification numbers together with cooling capacities and locations of the equipment. Description of method of control of temperature. Description of method of control of periods of operation. Reports from earlier inspections of air conditioning systems, and for the generation of an energy performance certificate Records of maintenance operations carried out including filter changing, cleaning indoor and outdoor heat exchangers, refrigerant leakage tests, repairs to refrigeration components or replenishing with refrigerant. Records of calibration and maintenance operations carried out on control systems and sensors Records of sub-metered air conditioning plant use or energy consumption. An estimate of the design cooling load for each system (if available). Otherwise, a brief description of the occupation of the cooled spaces, and of power consuming equipment normally used in those spaces. Records of any issues or complaints that have been raised concerning the indoor comfort conditions achieved in the treated spaces. 2 Inspection of packaged cooling systems This procedure would be appropriate when assessing packaged, split and multi-split packaged cooling equipment, including variable refrigerant flow (VRF) equipment, as indicated in section Checklist of pre-inspection information The building owner or manager should be asked to provide any available documentation for the cooling systems in readiness for the inspection. This would include, for example, catalogue information and details provided during the installation, commissioning and maintenance of the equipment. This information, see Table 2.1, will help to minimise the time and cost of the subsequent inspection process. Where the owner has not made the relevant documentation available at the time of the inspection, then the information noted in the Table 2.1 as essential would also need to be prepared as part of the inspection procedure. 2.2 Inspection process for packaged systems The items to be examined, and subsequent actions or advice that might be recommended, are described in the following paragraphs and summarised in the checklists shown as Tables 2.2 to System documentation The inspector should examine the relevant documentation and systems as far as possible to check that the installed equipment is as described. If the documentation is not available, then an additional part of this procedure is to locate the equipment and assemble a minimum portfolio of relevant documentation. The minimum content for the information that should be available in readiness for the inspection is indicated in section 2.1 above. (a) Record whether there is evidence of a regular inspection and maintenance regime carried out by suitably competent people. Record and comment on the frequencies and scope of maintenance to the air conditioning equipment and systems in relation to industry guidelines. This, along with the dates and activity schedule of the most recent maintenance, may also need to be referred to during the physical inspection. (b) Compare system sizes with likely loads. Section 4 contains simple procedures for assessing whether the systems are likely to be oversized Outdoor units (a) Locate and check the condition and operation of the outdoor units of split or multi-split systems, or the outdoor part of through the wall units.

14 Inspection of packaged cooling systems 7 (b) (c) (d) (e) Note the general state of the equipment and the space immediately around them. Note whether the area near the equipment (wherever installed) show signs of oily stains that could indicate refrigerant leakage. If present, check whether any attention to this is noted in the maintenance records. If an enclosure has been constructed to provide additional weatherproofing around the outdoor equipment, check that this does not obstruct the flow of air to and from the equipment, and that there are adequate openings for the free passage of air into and out of the enclosure. Check that the openings are not themselves obstructed either by proximity to adjacent structures, or by damage or debris. Check that the heat exchanger surfaces are free from debris and reasonably undamaged. Check whether the outdoor units are located close to a source of heat such as discharged air from other units or warm air exhausts, and for any potential for warmed air from the outdoor unit to be drawn into the building Indoor units (a) Locate and check the condition and operation of the indoor units within the treated spaces. (b) Assess the condition of heat exchangers. Note whether heat exchanger surfaces are significantly damaged, or blocked by debris or dust. Note any evidence of icing or excessive condensation. (c) Check the condition of air filters. (d) Note any evidence that occupants find the air distribution arrangements unacceptable, e.g. by taping over grilles or otherwise modifying the designed flow distribution. (e) Note the usual filter changing or cleaning frequency, and the elapsed time since the last change or clean, in relation to industry guidance System controls (a) Locate and examine the controls responsible for the operation of the cooling units, the heating system controls, and their associated temperature sensors. (b) Assess the appropriateness of the position of the cooling control sensor(s) in relation to factors such as local levels of internal gain, orientation and exposure to solar radiation. (c) Observe any control timers and note the current indicated weekday, and time of day against the actual time. Note the set times of on and off periods (for weekday and weekend if this facility is available with the timer). Form a view on the suitability of the timers and the suitability of the set periods in use. (d) Determine, if possible, the set temperatures in each relevant zone for heating and cooling. Form a view on the suitability of the set temperatures in relation to the activities and occupancy of the zones and spaces, in relation to the manager s intent, and in relation to each other. A change of (e) (f) set temperature of 1 C can significantly affect energy use. Note particularly whether there is a set dead band between the need for cooling and the need for heating, or other means of inhibiting the simultaneous operation of the heating and cooling equipment in the same location. Note whether the cooling units are installed to provide cooling in spaces with opening windows and, if so, whether there is any provision to disable operation of the equipment when windows are open, or whether there is visible guidance for the local user to ensure that the window is not open while the equipment is operating. Determine, if possible, the type and age of the cooling units and the method of cooling capacity control. Form a view of the likely efficiency compared to good current practice. 2.3 Reporting A report of the air conditioning inspection should be prepared and signed by the inspector. This should include at least the following details. Details of the property and the inspector: the address, name, or other unique identifier of the property the name of the owner or manager of the building the inspector s name, affiliation, and status (e.g. approved by [name of accreditation body] ) the date of the inspection. Details of the systems inspected: physical descriptions of the systems inspected, including the type of system (e.g. unitary, split, multi-split) an inventory of equipment inspected, including makes, models and serial numbers (if readily accessible), and their ratings the locations of the outdoor equipment and the areas served (including the locations of indoor equipment). Details of the results of the inspection: the results of any measurements or calculations reviewed or made for the inspection comments on the likely efficiency of the installation and any suggestions made for improvement comments on any faults identified during the inspection and suggested actions comments on the adequacy of equipment maintenance and any suggestions made for improvement comments on the adequacy of installed controls and control settings and any suggestions made for improvement comments on the size of the installed system in relation to the cooling load and any suggestions for improvement

15 8 Inspection of air conditioning systems Table 2.2 Packaged cooling systems: checklist for system documentation Item Inspection topic Advice PS1.1 Review available documentation. If missing or unsatisfactory then certain basic information will need to be prepared; see section 2.1 above for preparation of information. PS1.2 Locate the plant and compare details. Prepare revised information as necessary. PS1.3 Review current inspection and Compare with, and recommend, industry norm maintenance schedules. maintenance regime. PS1.4 Compare size with imposed cooling Report result of comparison; see section 5 for potential recommendations. loads (see section 4 for estimation and comparison procedure). PS1.5 Compare any records of use of the package, Excessive hours of use could indicate a control problem. Excessive energy consumption or sub-metered energy consumption with could indicate either a control problem or an installation/maintenance issue affecting the expected hours of use per year for the plant, efficiency of the system. or with appropriate energy benchmarks. Table 2.3 Packaged cooling systems: checklist for outdoor and indoor units Item Inspection topic Advice PS2.1 Locate outdoor and indoor plant. Note whether there are any discrepancies between actual and documented plant. PS2.2 Check for signs of refrigerant leakage. Visual signs of refrigerant leakage should be noted and, if present, evidence of attention to any leakage sought. If this has not been attended to, then recommend prompt skilled maintenance. PS2.3 Check that refrigeration plant is capable of Note where plant appears to contain no, or insufficient, refrigerant and recommend providing cooling by assessing temperature prompt skilled maintenance. difference, and observing the refrigerant sight glass, and/or refrigerant temperature or Note where heat exchanger may be partially blocked, or undersized. Recommend pressure gauges (where readily visible). cleaning as appropriate. Note any evidence of icing or excessive condensation. PS2.4 Check for obstructions to airflow through Check for any obstructions to airflow. Observe whether airflow is impeded, thus outdoor and indoor unit heat exchangers. affecting efficiency. Check condition of indoor unit grilles and filters. Note whether heat exchangers have adequate free access to outdoor air. Recommend removal of debris, or increasing openings in enclosures, cleaning or repair as appropriate. Note any potential for recirculation of warm air. PS2.5 Check location of outdoor unit for proximity Comment on location of unit and recommend seeking skilled advice if the outdoor unit to local sources of heat, such as discharged appears to be affected. air from other units or warm air exhausts. Table 2.4 Packaged cooling systems: checklist for system controls Item Inspection topic Advice PS3.1 Assess zoning in relation to factors such as Comment on appropriateness of zoning and recommend further investigation if unclear local levels of internal gain, orientation and and specialist advice if inappropriate. exposure to solar radiation. PS3.2 Note the current indicated weekday and time Recommend resetting if incorrect. of day on controllers against the actual time. PS3.3 Note the set on and off periods (for weekday Note any shortfall in the control timer capabilities, and recommend resetting if and weekend if this facility is available with current settings are inappropriate. the timer). PS3.4 Identify and assess zone heating and cooling Note the appropriateness of the type and location of sensors in relation to the heating temperature control sensors. and cooling emitters, heat flows or likely temperature distributions in the zone or space, and the intended function of the sensors. Identify areas of potential conflict between heating and cooling emitters and their controls. Recommend further investigation if unclear and specialist advice on replacement if inappropriate. PS3.5 Note the set temperatures in each zone for Note the suitability of the set temperatures and recommend re-setting as appropriate. heating and cooling in relation to the Recommend further investigation if unclear. activities and occupancy of the zones and spaces, in relation to the manager s intent. PS3.6 Note provision of controls or guidance to Advise as appropriate. inhibit use of equipment while windows are open PS3.7 Note the type, age and method of capacity Compare with current good practice equipment. control of the equipment.

16 Inspection of centralised cooling systems 9 comments concerning alternative solutions (for guidance, see section 5) summary of the findings and recommendations of the inspection Additional advice: sources of good practice publications on the ownership and efficient operation of air conditioning systems sources of funding that might support further investigations and improvements in efficiency. An example showing the nature and format of a typical inspection report is given in Appendix A Inspection checklist See Tables 2.2 to Inspection of centralised cooling systems This procedure would be appropriate when assessing systems that include centralised generation and distribution of cooled air or water, or systems of reversible heat pumps coupled to a controlled temperature common water loop, as indicated in section In addition, some areas may be served by packaged, split and multi-split packaged comfort cooling equipment, including variable refrigerant flow (VRF) equipment. Such equipment can be inspected using the procedure described in section 2, with the observations and advice on the equipment reported either separately or combined in the centralised system report. 3.1 Checklist of pre-inspection information The building owner or manager should be asked to provide any available documentation for the air conditioning systems in readiness for the inspection. This would include, for example, catalogue information and details provided during the installation, commissioning and maintenance of the equipment. The assembly of this information will help to minimise the time and cost of the subsequent inspection process. Where the owner has not made the relevant documentation available at the time of the inspection, then the information noted in Table 3.1 as essential would also need to be prepared as part of the inspection procedure. Table 3.1 Centralised cooling systems: checklist of pre-inspection information Level Essential Desirable Optional Information required Itemised list of installed air conditioning and refrigeration plant including product makes, models and identification numbers, together with cooling capacities, with locations of the indoor and outdoor components of each plant. Description of system control zones, with schematic drawings. Description of method of control of temperature. Description of method of control of periods of operation. Floor plans and schematics of air conditioning systems. Reports from earlier inspections of air conditioning systems, and for the generation of an energy performance certificate Records of maintenance operations carried out on refrigeration systems, including cleaning indoor and outdoor heat exchangers, refrigerant leakage tests, repairs to refrigeration components or replenishing with refrigerant. Records of maintenance operations carried out on air delivery systems, including filter cleaning and changing, and cleaning of heat exchangers. Records of calibration and maintenance operations carried out on control systems and sensors, or BMS systems and sensors. Records of sub-metered air conditioning plant use or energy consumption. For relevant air supply and extract systems, commissioning results of measured absorbed power at normal air delivery and extract rates, and commissioning results for normal delivered delivery and extract air flow rates (or independently calculated specific fan power for the systems). An estimate of the design cooling load for each system (if available). Otherwise, a brief description of the occupation of the cooled spaces, and of power consuming equipment normally used in those spaces. Records of any issues or complaints that have been raised concerning the indoor comfort conditions achieved in the treated spaces. Where a BMS is used the manager should arrange for a short statement to be provided describing its capabilities, the plant it is connected to control, the set points for the control of temperature, the frequency with which it is maintained, and the date of the last inspection and maintenance. Where a monitoring station, or remote monitoring facility, is used to continually observe the performance of equipment such as chillers, the manager should arrange for a statement to be provided describing the parameters monitored, and a statement reviewing the operating efficiency of the equipment. 3.2 Inspection process for centralised cooling systems The items to be examined, and subsequent actions or advice that might be recommended, are described in the following paragraphs and summarised in checklists in section Air conditioning system documentation The inspector should examine the relevant documentation and systems as far as possible to check that the installed equipment is as described. If the documentation is not available, then an additional part of this procedure is to locate the equipment and assemble a minimum portfolio of relevant documentation.

17 10 Inspection of air conditioning systems The minimum content for the information that should be available in readiness for the inspection is listed in section 3.1 above. (a) Record whether there is evidence of a regular inspection and maintenance regime carried out by suitably competent people. Record and comment on the frequencies and scope of maintenance to the air conditioning equipment and systems in relation to industry guidelines, This, and the dates of most recent maintenance may also need to be referred to during the physical inspection. (b) Compare system sizes with likely loads. Section 4 contains simple procedures for assessing whether refrigeration systems and air supply systems are likely to be oversized. (c) Estimate the specific fan power (SFP) of air movement systems, provided that this can be done simply from existing records of the installed fan capacities and the flowrates and pressure drops noted in commissioning records, for comparison with the guidance (13) associated with current Building Regulations Approved Document L2A (14) Refrigeration equipment (a) Locate any relevant refrigeration compressors. These are likely to be in the plant room (some centralised systems), in outdoor units (split and multi-split systems, and unitary air-cooled chillers) or in individual room units (distributed reversible systems). Check that these can be brought into operation. (b) If installed as separate plant, note the general state of the refrigeration equipment and the space immediately around it. Note whether the area near the equipment (wherever installed) shows signs of oily stains that could indicate refrigerant leakage. If present, check whether any attention to this is noted in the maintenance records. (c) In operation observe the temperature difference across the refrigeration compressor. Compared with the ambient temperature in the plant room (or indoors or outdoors), one side of the refrigeration circuit should be cold and the other warm while the compressor is working. These differences in temperature should be apparent when flow and return water pipework or refrigerant pipes to and from the refrigerant plant are measured using one or two surface temperature probes. If, while the refrigeration plant is operating, both flow and return appear to be at the same temperature, or warmer than the surroundings, then it may be that the equipment has lost its refrigerant charge, although this may not be the only cause. (d) If the refrigeration equipment includes a readily visible liquid sight glass, intended to show the state of the refrigerant in the system, this should be observed while the equipment is operating. If there is a reasonable difference between flow and return temperatures, but gas bubbles can be seen passing through the sight-glass, or a distinct liquid level line can be seen across the sight glass, then it may be that there is insufficient refrigerant in the system, although this may not be the only cause. (e) (f) (g) If the refrigeration equipment includes readily visible refrigerant temperature or pressure gauges, then the readings when the equipment is operating should be compared with the evaporating and/or condensing temperatures or pressures expected for the current indoor and outdoor temperatures. Evaporating pressure or temperature readings that are significantly lower than expected may indicate that the evaporator is partially blocked, or undersized. Condensing pressure or temperature readings that are significantly higher than expected may indicate that the condenser is partially blocked, or undersized. Pressures or temperatures that are significantly higher at the evaporator, and lower at the condenser, may indicate that insufficient refrigerant is contained in the system, which may be due to insufficient initial charging or to leakage, although this may not be the only cause. If the refrigeration equipment includes water chillers check that adequate water flows are available through the condensers and evaporators to achieve efficient heat transfer. Also check that the water pressure drops across them are in accordance with design or commissioning data if gauges or test points are available and accessible. The procedures described apply primarily to electrically driven vapour compression refrigeration, but most observations also apply generally to other forms of refrigeration equipment including engine-driven systems, and direct or heat powered absorption refrigeration plant Heat rejection equipment (a) Locate and check the condition and operation of heat rejection units. (b) If there is an enclosure around the heat rejection equipment, check that this does not obstruct the flow of air to and from the equipment, and that there are adequate openings for the free passage of air into and out of the enclosure. Check that the openings are not themselves obstructed either by proximity to adjacent structures, or by damage or debris. (c) Check that the heat exchanger surfaces are free from debris and reasonably undamaged. (d) Check for the possibility of air short-circuiting, in which exhaust air that has passed through the heat exchanger is subsequently re-admitted to the heat exchanger air inlet. (e) Check for oily staining on direct expansion heat exchanger surfaces that might indicate leakage of refrigerant. If present, check whether this is noted in the maintenance records. (f) In operation, check the rotation and control of heat rejection fans to ensure that fan operation varies with the heat rejection loads. (g) If cooling towers or evaporative coolers are used ensure that the water distribution is even across the surfaces and all sprays and nozzels are free flowing, evenly adjusted and not causing excessive water loss through spashing or overflow.

18 Inspection of centralised cooling systems 11 (h) (i) (j) Check that there is no restriction to water flow from any cooling tower bund or enclosure and that outlet pipes and strainers appear clear. (Note: this may not be possible with the plant running and the operator must be consulted if detailed inspection is considered necessary.) Check the route and condition of any cooling water system linking the refrigeration plant with the heat rejection units are satisfactory and ensure that the system is efficiently controlled, especially on part load, and not subject to extraneous heat gains. If the plant and heat rejection controls provide a free cooling facility with low ambient temperatures, check that this is operating correctly Waterborne cooling systems and air conditioning systems (a) (b) (c) (d) (e) (f) (g) (h) (i) (j) Check that the route and condition of any cooling or chilled water system serving local cooling units (e.g. fan coils or individual heat pumps) is satisfactory and that the system is effectively controlled. Locate and check the condition and operation of the local heat exchange units installed in or serving treated spaces. Check that the heat exchanger surfaces are free from debris and reasonably undamaged. Check the condition of intake air filters. Check that inlet and outlet grilles (where appropriate) are not obstructed either by proximity to adjacent structures, or by damage or debris. In operation, check the rotation and control of heat exchange fans. When fan coil units are supplied with chilled and hot water check that the controls are correctly set to ensure that the units are not receiving both simultaneously. In the case of local heat pump units check the operation of the compressors to ensure adequate charge of refrigerant, and that cycling and frosting are not occurring. Check for staining on direct expansion heat exchanger surfaces that might indicate leakage of refrigerant. If present, check whether this is noted in the maintenance records. If the system consists of many local units only a representative sample should be inspected, as directed in section Airborne cooling systems and air conditioning systems in treated spaces (a) Locate the air delivery and extract openings, grilles or diffusers in the treated spaces, identifying the airflow arrangement for all unique situations and any potential for short-circuiting. If ceilings or other access routes are openable, note any signs of air leakage from visible ducts. (b) (c) (d) (e) Note any evidence that occupants find the air distribution arrangements unacceptable, e.g. by taping over grilles, or otherwise modifying the designed flow distribution by such means as closing dampers, blocking air paths with furniture or similar obstructions, or wedging doors open. Observe whether building modifications, partitioning or fitted furniture are likely to be affecting the performance of the system through obstruction or otherwise. Using a random sample as indicated in section 1.7.2, but preferably towards the extremity of the system, check that airflow is apparent through the identified openings. Where the airflow to separate spaces is subject to individual temperature and volume control check a random sample to ensure that they are functioning satisfactorily and are not in conflict with other forms of heating within the space Airborne cooling systems and air conditioning systems at air handling units and associated ductwork For safety reasons, it will be necessary for air handling fans in air distribution systems to be turned off in order to gain access inside air handlers or ductwork to examine components such as fans, drives, filters, heat exchangers and control dampers. The building manager should arrange safe access for the inspector. (a) (b) (c) (d) (e) (f) Note the usual filter changing or cleaning frequency, and the elapsed time since the last change or clean, in relation to industry guidance. Assess the state of cleanliness, damage or blockage of filters. Filter housings may be fitted with a differential pressure gauge giving an indication of blockage while the system is in operation. If it is in good condition this may be used to assess filter blockage. If the gauge is itself inoperable, then this should be noted. Where gauges are inoperable or missing, a measurement should be made of the filter resistance where this is reasonably practical. Access the interior of the air handling unit to observe filter condition directly, and check the fit and sealing of the filter and housing within the duct. Assess the condition of heat exchangers. Note whether any heat exchanger surfaces are significantly damaged, or blocked by debris or dust. Where reasonably practical, and where suitable information is available for comparison, the air path resistance across the coil should be measured and compared with the design resistance. Note whether refrigeration heat exchangers show signs of oily staining that could indicate refrigerant leakage. If present, check whether any attention to this is noted in the maintenance records. Note the fan type, and method of control. Identify whether the systems have any energy conservation facilities, e.g. heat recovery, free cooling sequence, and check for evidence that such facilities are/have been functioning.

19 12 Inspection of air conditioning systems (g) (f) Observe the air handling plant and visible air containment including ductwork, floor or ceiling plenums and builders work shafts for signs of excessive leakage and energy loss. Where these may be visible to the inspection, note the setting and functioning of any dampers that modulate the proportions of fresh and recirculation air Outdoor air inlets (a) Locate the inlets for outdoor air. (b) Note any significant obstructions or blockages to inlet grilles, screens and pre-filters. (c) Note where inlets may be affected by proximity to local sources of heat, or to air exhausts System controls (a) Locate and examine the controls responsible for the operation of the air conditioning or comfort cooling system, the heating system controls, and their associated temperature sensors. (b) Review documentation or other sources of information to determine the individual control zones for heating and cooling. Form a view of the appropriateness of zoning in relation to factors such as local levels of internal gain, orientation and exposure to solar radiation. (c) Observe any control timers and note the current indicated weekday, and time of day against the actual time. Note the set times of on and off periods (for weekday and weekend if this facility is available with the timer). Form a view of the suitability of the timers and the suitability of the set periods in use. (d) Note the locations of zone heating and cooling temperature control sensors. Form a view of the appropriateness of the type and location of sensors in relation to the heating and cooling emitters, heat flows or likely temperature distributions in the zone or space, and the intended function of the sensors. (e) Determine, if possible, the set temperatures in each zone for heating and cooling. Form a view on the suitability of the set temperatures in relation to the activities and occupancy of the zones and spaces, in relation to the building manager s intent, and in relation to each other. Note particularly whether there is a set dead band between the need for cooling and the need for heating. (f) Where timing and set temperatures are part of the function of a BMS, the building manager or maintenance agent should interrogate the BMS or otherwise provide documentation, to demonstrate the current values of these timers and temperatures. (g) Determine, if possible, the type and age of the refrigeration compressor(s) and method of refrigeration capacity control. Form a view of the likely efficiency compared to good current practice. (h) Determine, where applicable, the method used to set, modulate or control air flow rate through air supply and exhaust ducts. Form a view of the likely efficiency compared to good current practice. If available, the BMS may also indicate air supply and exhaust flowrates. 3.3 Reporting A report of the air conditioning inspection should be prepared and signed by the inspector. This should include at least the following details. Details of the property and the inspector: the address, name, or other unique identifier of the property the name of the owner or manager of the building the inspector s name, affiliation, and status (e.g. approved by [name of accreditation body] ) the date of the inspection. Details of the systems inspected: physical descriptions of the systems inspected including types of system (e.g. chilled water with fan coils, VAV air conditioning) the inventory of equipment inspected including manufacturer and duty the location of equipment and areas served. Details of the results of the inspection: the results of any measurements or calculations reviewed or made for the inspection comments on the likely efficiency of the installation and any suggestions made for improvement comments on any faults identified during the inspection and suggested actions comments on the adequacy of equipment maintenance and any suggestions made for improvement comments on the adequacy of installed controls and control settings and any suggestions made for improvement comments on the size of the installed system in relation to the cooling load and any suggestions for improvement comments concerning alternative solutions (for guidance see section 5) summary of the findings and recommendations of the inspection Additional advice: sources of good practice publications on the ownership and efficient operation of air conditioning systems sources of funding that might support further investigations and improvements in efficiency. An example showing the nature and format of a typical inspection report is given in Appendix A1.

20 Inspection of centralised cooling systems 13 Table 3.2 Centralised cooling systems: checklist for system documentation Item Inspection topic Advice CS1.1 Review available documentation. If missing or unsatisfactory then certain basic information will need to be prepared; see section 3.1 above for preparation of information. CS1.2 Locate relevant plant and compare details. Prepare revised information as necessary. CS1.3 Review current inspection and maintenance Compare with, and recommend industry norm maintenance schedules. regime. CS1.4 Compare system size with imposed cooling See section 5 for recommendations. loads (see section 4 for estimation and comparison procedure). CS1.5 Estimate specific fan power of relevant If commissioning flowrates are not available, recommend that these are measured. If the air movement systems (see section 4 for result is significantly higher than the current Building Regulations* recommendations, calculation procedure). the assessor should seek during the inspection to form a view of the reason. For example: likely efficiency of fan and drive; air velocities in ductwork; degree of closure of balancing dampers. CS1.6 Compare any records of air conditioning Excessive hours of use could indicate a control problem. Excessive energy consumption plant usage or sub-metered energy could indicate either a control problem or an installation/maintenance issue affecting consumption with expected hours of use the efficiency of the system. per year for the plant, or with appropriate energy benchmarks. * See Non-Domestic Heating, Cooling and Ventilation Compliance Guide (13) Table 3.3 Centralised cooling systems: checklist for refrigeration plant Item Inspection topic Advice CS2.1 Locate refrigeration plant and check operation. Note whether there are any discrepancies between actual and documented plant. Note whether plant is operational. CS2.2 Visual appearance of refrigeration plant and Note whether the plant appears clean and unobstructed. If dirty and cluttered, then immediate surrounding area. regular inspection and maintenance is unlikely and this should be noted; recommend the plant is kept clear and properly maintained. Visual signs of refrigerant leakage should be noted and, if present, evidence of attention to any leakage sought. If this has not been attended to, then recommend prompt skilled maintenance. CS2.3 Check that refrigeration plant is capable of Note where plant appears to contain no, or insufficient, refrigerant and recommend providing cooling by assessing temperature prompt skilled maintenance. Note where evaporator or condenser may be partially difference, and observing the refrigerant blocked, or undersized. If no problems are apparent in subsequent visual inspection, sight glass, and/or refrigerant temperature then recommend prompt skilled maintenance. Recommend cleaning evaporator or or pressure gauges (where readily visible). condenser as appropriate. Note any evidence of icing or excessive condensation. Note excessive noise or vibration from the plant. Table 3.4 Centralised cooling systems: checklist for heat rejection equipment Item Inspection topic Advice CS3.1 Visual check of the condition and operation Note whether units have adequate free access to outdoor air. Recommend removal of of outdoor heat rejection units. debris, or increasing openings in enclosures, as appropriate. CS3.2 Check for obstructions to airflow through Recommend cleaning or repair as appropriate. heat rejection units. CS3.3 Check for signs of refrigerant leakage. Visual signs of refrigerant leakage should be noted and, if present, evidence of attention to any leakage sought. If this has not been attended to, then recommend prompt skilled maintenance. CS3.4 Check for the correct rotation of fans. If Note whether fan rotates in the correct sense, and whether speed control or modulation possible, observe the modulation of multiple is operational. If incorrect or defective, recommend skilled rectification or maintenance. fans in response to load changes. CS3.5 Check that water flow through cooling towers Observe signs of poor water distribution or excessive overflow and recommend action or evaporative coolers is even and efficient, or maintenance. and there is no loss of water. CS3.6 Check that water tanks or bunds are free of Recommend maintenance as appropriate. debris and outlets are running free. CS3.7 Check the route and condition of all heat Note whether pipework attracts avoidable heat gain and whether water circulation varies rejection pipework and the efficiency of with load and recommend suitable action. its operation. CS3.8 Check whether the heat rejection equipment Advise that operation of such a system should be verified under low ambient and pipework circuitry provide a free cooling temperature conditions. facility under certain conditions.

21 14 Inspection of air conditioning systems Table 3.5 Centralised cooling systems: checklist for waterborne cooling and air conditioning systems Item Inspection topic Advice CS4.1 Visually inspect the route and condition of the Advise whether pipework is subject to unwanted heat transfer and energy losses and the cooling system pipework serving local areas. flow is efficiently controlled. CS4.2 Visually check the condition and operation Note whether units have adequate free access to indoor air. Recommend removal of of indoor units. debris or blockage as appropriate. CS4.3 Check for obstructions to airflow through Recommend cleaning or repair as appropriate. Note any evidence of icing or excessive heat exchangers. condensation. CS4.4 Check condition of intake air filters. Recommend cleaning or replacement as appropriate. CS4.5 Check air inlets and outlets for obstruction. Note whether units have adequate free access to indoor air. Recommend removal of debris or blockage as appropriate. CS4.6 Check for the correct rotation of fans. If Note whether fans rotate in the correct sense, and whether speed control or modulation possible, observe any facility to modulate is operational. If incorrect or defective, recommend skilled rectification or maintenance. their speed in response to load changes. CS4.7 Check that chilled and hot water are not Advise that controls equipment requires checking for faulty components or the control being supplied to terminals simultaneously. strategy needs to be revised. CS4.8 Check that local heat pumps are running Incorrect operation is likely to be caused by loss of refrigeration. correctly with no cycling or frosting of coils. CS4.9 Check for signs of refrigerant leakage. Visual signs of refrigerant leakage should be noted and, if present, evidence of attention to any leakage sought. If this has not been attended to, then recommend prompt skilled maintenance. Table 3.6 Centralised cooling systems: checklist for airborne cooling and air conditioning systems Item Assessment topic Advice CS5.1 Review air delivery openings, grilles or Note whether these appear to provide good distribution, or whether there is evidence of diffusers, and route by which air is extracted occupant tampering. from the spaces. CS5.2 Review any evidence that occupants find the If present, recommend more detailed assessment by ventilation specialist. air delivery arrangement unacceptable. CS5.3 Assess the positioning and geometry of air Note where there may be potential that air might short-circuit from supply to extract. supply openings in relation to extract openings. If suspected, this might be checked visually using a smoke-pencil. Where relative positioning of inlet and extract is sure to cause direct short-circuit, recommend that alternatives are sought. CS5.4 Observe if partitioning or furniture is affecting Suggest modifications to improve performance. performance. CS5.5 Assess the controllability of a sample number. Comment on the adequacy of control and operation. of terminal units. Table 3.7 Centralised cooling systems: checklist for airborne systems in air handling units and ducts Item Assessment topic Advice CS6.1 Review filter changing or cleaning frequency. Recommend adopting good practice industry guidance on cleaning and replacement if not in place. CS6.2 Assess the current state of cleanliness or Recommend replacement if appropriate, and adopting good practice industry guidance blockage of filters. on cleaning and replacement. CS6.3 Note the condition of filter differential Recommend rectification if inoperable. pressure gauge. CS6.4 Assess the fit and sealing of filters and housings. Recommend skilled maintenance if visibly poorly fitted. CS6.5 Examine heat exchangers for damage, or Recommend cleaning or skilled maintenance as appropriate. significant blockage by debris or dust. CS6.6 In addition examine refrigeration heat Visual signs of refrigerant leakage should be noted and, if present, evidence of attention exchangers for signs of refrigerant leakage. to any leakage sought. If this has not been attended to, then recommend prompt skilled maintenance. CS6.7 Note fan type and method of air speed control. Compare with current good practice and identify opportunities for improvement. CS6.8 Note the type of energy conservation Recommend maintenance if not functioning and additional facilities if beneficial and facilities incorporated in the system. appropriate. CS6.9 Inspect air handling units and associated air Recommend reasonable action to reduce the air and energy losses. paths for signs of leakage CS6.10 Check the setting and operation of any Comment on the appropriateness of the settings and performance. fresh air/recirculation dampers.

22 Assessing equipment sizing in relation to the cooling load 15 Table 3.8 Centralised cooling systems: checklist for outdoor air inlets Item Assessment topic Advice CS7.1 Check for obstructions or blockages to inlet Recommend clearing or cleaning as appropriate. grilles, screens and pre-filters. CS7.2 Check location of inlets for proximity to local Comment on location of air inlets and recommend seeking skilled advice if these appear sources of heat, or to air exhausts. compromised. Table 3.9 Centralised cooling systems: checklist for system controls Item Assessment topic Advice CS8.1 Assess zoning in relation to factors such as Comment on appropriateness of zoning and recommend further investigation if unclear local levels of internal gain, orientation and and specialist advice if inappropriate. exposure to solar radiation. CS8.2 Note the current indicated weekday and time Recommend resetting if incorrect. of day on controllers against the actual time. CS8.3 Note the set on and off periods (for weekday Note any shortfall in the control timer capabilities, and recommend resetting if and weekend if this facility is available with unsuitably set. the timer). CS8.4 Identify and assess zone heating and cooling Note the appropriateness of the type and location of sensors in relation to the heating temperature control sensors. and cooling emitters, heat flows or likely temperature distributions in the zone or space, and the intended function of the sensors. Recommend further investigation if unclear and specialist advice on replacement if inappropriate. CS8.5 Note the set temperatures in each zone for Note the suitability of the set temperatures and recommend re-setting as appropriate. heating and cooling in relation to the Recommend further investigation if unclear. activities and occupancy of the zones and spaces, in relation to the manager s intent. CS8.6 Note whether a dead band is or can be set Recommend resetting as appropriate. Recommend further investigation if unclear. between heating and cooling. CS8.7 Assess the refrigeration compressor(s) and Provide a view of the likely efficiency compared to good current practice, and the method of refrigeration capacity control. recommend further investigation if there appears to be significant potential for improvement. CS8.8 Assess means of modulating or controlling Provide a view of the likely efficiency compared to good current practice, and air flow rate through air supply and exhaust recommend further investigation if there appears to be significant potential for ducts. improvement. 3.4 Inspection checklists See Tables 3.2 to Assessing equipment sizing in relation to the cooling load Regulation 22 (1) of the EPB Regulations requires that: The inspection report must include an assessment of the airconditioning efficiency and the sizing of the system compared to the cooling requirements of the building, and contain appropriate advice on possible improvements to the system, replacement of the system and alternative solutions. During the design of a new building, or of a new air conditioning installation, detailed calculations are undertaken to establish with reasonable accuracy the cooling loads in the building, or the part to be served by the new installation. However, such detailed calculations are beyond the scope of what is intended as part of an air conditioning inspection under the EPB Regulations. What is intended for these purposes is an estimate of the current loads and an indication of whether the system is of an appropriate size. This will inform building owners of the current state of the building and system, and is intended to assist them in making decisions about future maintenance, replacement or upgrading of the system. Where a system is nearing the end of its useful life, this assessment will help to inform the owner about whether it would be appropriate to replace the existing system on a like-for-like basis, or whether a smaller, more efficient system will meet the needs. It may indicate that there is a specific and localised load, for example a server room, that requires special cooling measures. It may indicate that the current system is significantly oversized and therefore costing the owner much more to operate than an appropriately sized, efficient system, and may influence a decision to replace the oversized system. It therefore follows that the assessment should serve two purposes. It should identify indications of significant oversizing, and therefore waste of energy, based on actual operational experience, and inform users of appropriate levels of cooling for consideration when planning replacements. Owners are unlikely to act on a five year old system that is 20% over the optimum size. But they may be prompted to take early action to replace a ten year old system that is twice the required size. The above extract from the EPB Regulations (1) refers to assessment of the air conditioning efficiency and the

23 16 Inspection of air conditioning systems sizing of the system. Assessment is not the same as detailed calculation and the effort put into the assessment of the cooling load should be proportionate to the size of the system being assessed. Many individual packaged, split or multi-split units are installed to serve areas where the activity in the space is similar to general light office use and in these cases the assessment should follow the guidance given in section 4.1. It is possible to form a reasonable estimate of the cooling load for common building types, and hence to form an estimate of the size of plant that would normally be appropriate, using simple observations, rules of thumb, and knowledge of the air conditioned floor area. These rules are historical and, as a consequence of changes in Building Regulations and forms of construction, tend to be conservative. For modern buildings which comply with Part L (4) or later, these rules of thumb are likely to overestimate loads by 15 20%, and this should be borne in mind when these rules are considered. 4.1 Estimating loads for packaged systems A simple industry rule of thumb for installations of packaged air conditioning systems indicates that units installed to serve spaces up to 7 meters from window walls exposed to solar gain may need to provide cooling of around 100 W m 2 where the glazing is 25% of the wall area, increasing to 160 W m 2 where the glazing proportion is 60%. Where units are installed in internal areas, away from window walls, the load may be around 75 W m 2. Where the units serve larger areas including both perimeter (at about 30% glazing) and inner areas, this may average out to about 110 W m 2 of the conditioned area. Using these figures, a packaged unit with a rated output of 12 kw would be expected to serve an internal floor area, away from a window wall, of 160 m 2. A large room at the perimeter of a light industrial unit, with 60% glazing on the window wall, with 10 m of window wall and 8 m deep, could require as much as 12.8 kw, with a load of 160 W m 2. These are obviously estimates, and they do not take account of the orientation of the space and any windows, or of any shading of the windows, either using blinds, external devices, or trees and other vegetation. A north facing shaded space is likely to provide a lower load than a highly glazed south facing space with no shade. These rules also do not take account of whether the space is on a ground floor with further conditioned space above, or below a roof area. In the industrial example above this difference between ground floor and top floor could have a significant bearing on the cooling load. Such factors should be noted in the assessment report if they are considered significant. 4.2 Estimating loads for larger installations For larger installations, particularly with centralised systems, information regarding the sizing of the air conditioning plant to meet the cooling load may be available from documented sources. For newer buildings this should be found in the building log book. For buildings that have recently been sold or rented an assessment of plant and equipment may have been carried out in order to prepare an Energy Performance Certificate and Recommendation Report for compliance with the EPB Regulations (1). In the absence of recorded information from these sources, particularly in more extensive systems or where the activity in the treated space differs significantly from general light office use, the inspector may need to form a more specific estimate of cooling load. This estimate should be based on the area air conditioned, and should take account of the occupants, their levels of activity, lighting and energy consuming equipment, solar and ventilation heat gains. In the time available for the inspection it will not be possible to estimate the cooling load accurately, and so the estimate will need to be based on quickly observable factors and information that could be obtained readily from the building manager such as floor areas, the numbers of occupants, and the use of computers and other heat producing equipment. CIBSE Guide A: Environmental design (15) contains much helpful information and several tables of data that may be used to estimate heat gains and hence cooling loads. Recent studies of the cooling load of internal areas in typical offices have shown that the heat gain or cooling load is related to the occupant density (16). Figure 4.1 shows Heat gains / W m 2 total floor area Occupant density / m 2 total floor area per person Figure 4.1 Variation of calculated total heat gains with occupation density (source: CIBSE Guide A (15) ) that for an occupant density of 5 m 2 per person, gains are between 60 and 100 W m 2. At a density of 12 m 2 per person, gains are between 30 and 50 W m 2. Using these data may provide a quick estimate of loads in a large air conditioned building on a floor-by-floor basis. However, care must be taken to identify any special sources of heat gains, such as server rooms, areas with display lighting, catering areas or clusters of large office equipment, which may add to the loads covered in this graph. 24

24 Assessing equipment sizing in relation to the cooling load Assessment of cooling capacity Packaged systems For packaged systems the rated cooling capacity should be given on the equipment rating plate. Electrically driven vapour compression systems installed within the last few years should also be clearly identifiable. Performance data for these systems, predominantly provided by manufacturers, may be available via the Eurovent online database (17). Where the cooling output is not stated, then it may be calculated from the electrical input power and the coefficient of performance (CoP), or the energy efficiency ratio (EER), if both are known. However, where the cooling capacity is not known, the rated input and CoP or EER may not be available either. Where there is no available information about the cooling capacity, it may be possible for an experienced inspector to provide an estimate of the likely cooling capacity based on the size and likely age of the equipment. The key recommendation under these circumstances should be to review the cooling needs carefully prior to specifying a replacement, to ensure that it is appropriately sized for the requirements, and not merely to specify a like for like replacement of the existing equipment Centralised systems The electrical input and the rated capacity or output of the plant should be available from rating plates. If these are missing then the O&M manual should be consulted, although if the rating plates are missing the O&M manual may also be incomplete, out of date, or difficult to access. In the absence of clear evidence about the cooling capacity, the inspector will need to form a view about the likely capacity of the system, based on what can be observed and experience of other installations. Where it is not possible to obtain specific information from the inspection, this should be reported. Inadequate information about the plant may indicate that other aspects of the maintenance regime could be improved, and this should also be noted. Where it is not possible for the inspector to form a reasonable view on the cooling capacity and compare it to the estimates of cooling requirements, then the report should indicate this, and may recommend that further work is undertaken to establish the capacity in relation to the actual load. As with packaged systems, the key recommendation under these circumstances should be to review the cooling needs carefully prior to specifying a replacement, to ensure that it is appropriately sized for the requirements, and not merely to specify a like-for-like replacement of the existing equipment. Further information on the performance of refrigeration systems can be found in chapter 4 of CIBSE Guide B (18). 4.4 Assessment of ventilation performance The energy consumed by the ventilation system is important, as it can be a significant proportion of overall building energy use. Energy used for ventilation may increase because of changes in the way the building is used compared to the design intent. For an air conditioning inspector, the key is to assess how the building is currently used, rather than how it was designed to be used. The two major considerations in assessing the efficiency of an air distribution system are the volume of air being circulated, or ventilation rate through the building, and the total power required by the various supply and extract fans Airflow rates The inspector should note the airflow rates provided by the fans in relation to the likely ventilation requirements of the building. Indicators of the ventilation requirements include the number of occupants, the volume treated, and any particular sources of contamination, heat gains or odours (such as kitchens). Fan duties should be available from O&M manuals or building log books, failing which nameplate information may need to be inspected although this will invariably require the plant to be isolated and hence the user s authority obtained (see section 1.7.1). The air flow rate being supplied at any particular time will depend on the ventilation control system which the inspector should assess before comparisons with the estimated requirement or any recommendations are made. It is important to note that these ventilation rates, and those prescribed in Building Regulations Approved Document F: Means of ventilation (19), are the rates deemed necessary to supply sufficient fresh air for human occupants. If the ventilation system is also required to cool some or all of the spaces served, then there is a need for additional airflow above that required purely for ventilation. The total volume of air supplied is a function of the duty of the equipment and its control facility. Inspectors should therefore take note of these aspects of the system during the inspection procedure. Table 4.1 Indicative ventilation rates for various types of building (source: BSRIA BG14/2003 (20) ) Building type Air volume / (l s 1 per person) Offices (general) 10 Banks 8 Computer suites 8 Restaurants 8 Retail buildings 8 Table 4.2 Yardstick installed fan capacities (source: BSRIA AG1/2000 (21) ) Building type Yardstick capacity / (l s 1 per m 3 ) Offices (general) 1.4 Retail 2.1 Halls and theatres 2.1 Restaurants 3.5

25 18 Inspection of air conditioning systems The ventilation (fresh) air volume requirements of various types of building are listed in chapter 1 of CIBSE Guide A, which takes account of the building use and occupancy. They are also set out in Building Regulations Approved Document F (19). In the particular case of office ventilation Approved Document F (2006) indicates a whole building ventilation air supply rate of 10 litre s 1 per person. Inspectors may also wish to note the indicative ventilation rates provided in BSRIA BG14/2003: Rules of thumb (20), reproduced in Table 4.1. Some general yardsticks for installed fan capacity, in litre s 1 per m 3 of treated space, are indicated in Table 4.2, reproduced from BSRIA Application Guide AG 1/2000 (21). Where an inspector considers that the ventilation rate is below that required to provide adequate fresh air supply, that should be noted in the inspection report Specific fan power A measure of the efficiency of a ventilation system is the specific fan power. Guidance (13) associated with Building Regulations Approved Document L2A (14) (2006) defines the specific fan power (SFP) as: the sum of the design total circuit-watts, including all losses through switchgear and controls such as inverters, of all fans that supply air and exhaust it back to outdoors (i.e., the sum of the total circuit-watts for supply and extract fans), divided by the design ventilation rate through that system. Where possible, the specific fan power of the supply and extract installation should be determined and compared with the current level recommended in the Non-domestic Heating, Cooling and Ventilation Compliance Guide (13). The result of an SFP calculation for the air supply and extract system may have been provided as part of the information supplied prior to the inspection (see section 3.1), or may be provided in the building log book. If a calculation result has not been provided, then the inspector may be able to calculate the SFP from the installed fan capacities and airflow rates. Information concerning the installed fan capacities and airflow rates delivered should have been provided among the information supplied prior to the inspection. If this has not been provided than the information may be found in documented sources such as the building O&M manuals, the health and safety file, the building log book, or from an inspection carried out to meet other requirements such as the provision of an Energy Performance Certificate for compliance with the EPB Regulations (1). 5 Advice and alternative solutions 5.1 Introduction The inspector should look for, and include in the report to the building owner/manager, significant opportunities to reduce cooling loads by the application of simple measures that have a high probability of being cost effective. Detailed cost effectiveness studies would be outside the scope of this inspection, but a number of opportunities may be considered worthwhile recommending for further study by specialists. These should generally include alterations that could be made at relatively low cost, particularly those that might be considered when older equipment is due for replacement, which would allow the loading on cooling equipment to be reduced or would increase the opportunity to make use of natural ventilation, or lower energy alternatives to mechanical cooling, for at least part of the time. 5.2 Cooling load reduction The effects of reducing cooling loads are not straightforward as there can be instances where reducing the load on plant could reduce efficiency and might also have an adverse effect on the reliability and life of the refrigeration plant. It will be more effective where equipment is inherently able to operate reliably and efficiently at reduced loading either as a result of its type and form of capacity control, or in modular systems comprising multiple compressors. The worst situation could be where cooling is provided by an older individual unit with only simple on/off control. However, there will also be instances where reducing cooling loads may allow mechanical cooling systems to be turned off altogether for longer periods of the year. Cooling loads generally are influenced by: solar gains through glazing heat gains from artificial lighting heat gains from the occupants heat gains from IT and other equipment heat gains from ventilation air. Provided the air conditioning system is considered suitable to benefit from the reduction of cooling load, then opportunities should specifically be sought in each of these areas Solar shading, fixed or movable South facing glazing can make a significant, and in some cases the largest, contribution to cooling load, particularly in perimeter spaces where glazing areas exceed 40%. Internal blinds have limited effect in reducing such gains, which are better treated by the use of overhangs or external shading. Some film window treatments can be effective in reducing solar gains, although treatments that could produce a darkened indoor environment should not generally be recommended as these may also increase the use of artificial light and thus fail to reduce the cooling load Higher efficiency, better controlled, lighting Older lighting systems may be relatively inefficient and may also provide higher illumination levels than are recommended in current guidance. Such systems may contribute a significant proportion of the cooling load,

26 Advice and alternative solutions 19 and could be improved relatively easily. The appropriateness of illumination levels can be simply measured using a lux meter, and the result compared with current guidance for the particular activity in the Society for Light and Lighting s Code for lighting (22). The type of lamp and luminaire predominantly in use should also be identified, and the efficiency compared with the current guidance of Building Regulations Approved Document L2 (14). Switching and lighting control arrangements should also be assessed and compared with current guidance, as there may be significant opportunities to reduce average loads through localised switching and/or occupancy or daylight level controls. Guidance is provided in CIBSE Lighting Guide LG10: Daylighting and window design (23) IT equipment energy Where IT and other equipment is relatively old, and particularly where such equipment is being considered for replacement, opportunities should be encouraged to replace with low energy equipment. Much IT equipment, such as personal computer monitors, printers and copiers, is now available with a low energy sleep facility to reduce energy use, and hence heat gains, when not in use for significant periods Co-location and separate treatment of shared equipment There may be opportunities to move certain heat generating equipment, such as printers and copiers, away from the general work areas into separate rooms where the heat gains may be dealt with either by the use of opening windows or by providing simple extract ventilation. Advice for specific sectors is available free of charge in various publications from the Carbon Trust ( carbontrust.co.uk) Ventilation air The appropriateness of the ventilation airflow rate provided by mechanical systems is addressed elsewhere in this document (section 4.4.1). In considering equipment sizing, and the inspector should note that a consequence of providing significantly more ventilation air than necessary during hot weather would be increased loading on cooling systems (and probably increased loading on associated heating systems in cold weather). Where cooling systems are used in spaces with access to opening windows, then the inspector should ensure that the building owner or manager is made aware that windows should normally be closed (although trickle vents should be open as necessary) when the cooling equipment is in use, and the effect that opening windows would have on energy use. The manager should be advised to ensure that occupants are made aware of this need, or to consider installing interlocks between windows and cooling equipment in the associated spaces. 5.3 Alternative cooling techniques Free cooling Larger, centralised, systems using a cooling tower or dry air cooler may be suitable for conversion to employ free cooling techniques for some proportion of the time. In mid-season conditions, such as in spring and autumn, air temperatures may be sufficiently low that heat may be rejected from the chilled water circuit to atmosphere, through the cooling tower or dry air cooler, without operating mechanical cooling plant. One method involves the introduction of an intermediary heat exchanger to the chilled water circuit, transferring heat to a separate water circuit which rejects heat through the cooling tower or dry air cooler. Guidance on the potential use of such free cooling techniques is provided in chapter 4 of CIBSE Guide B (18). Further information and guidance is also available in BSRIA BG 8/2004: Free cooling systems (24) Absorption cooling with CHP Where buildings are provided with combined heat and power systems to generate electricity and to service winter heating loads, and where waste heat temperatures are suitable, there may be opportunities to employ absorption cycle refrigeration systems. These make use of the heat generated by the CHP plant in summer, when there is little or no heat demand, to provide cooling. This would offset the use of electric vapour compression refrigeration systems and may increase the proportion of the year where the CHP might usefully be operated. Guidance on the potential to use absorption cooling in CHP applications is provided in chapter 4 of CIBSE Guide B (18) Efficient cooling and heating units Some central cooling plant, and many of the currently available unitary and packaged split and multi-split equipment can operate to provide cooling and, in heat pump mode, heating. For unitary and packaged units the inspector should note the likely efficiency of the units installed in comparison with that achievable using similar equipment that meets the current standards for inclusion in the Energy Technology List (25) (ETL) as being eligible under the Enhanced Capital Allowance (ECA) scheme operated by the Department for Environment, Food and Rural Affairs (DEFRA), HM Revenue and Customs, and the Carbon Trust. Products included in the ETL meet specific efficiency standards in both cooling and heating modes. Packaged chillers that offer both cooling and (heat pump mode) heating must also meet specific efficiency standards in both cooling and heating modes for inclusion on the ETL. Such equipment may represent an attractive option when units are being considered for replacement, and where the heating function may be more efficient that the method currently used Further information and support AUDITAC is the acronym for an EU-funded project Field Benchmarking and Market Development for Audit

27 20 Inspection of air conditioning systems Methods in Air Conditioning which has studied air conditioning inspections. The core aims of the AUDITAC project are to provide tools and information that will enable air conditioning system inspectors, auditors, owners and operators across Europe to confidently identify actions that will save them money, and reduce greenhouse gas emissions. The AUDITAC project has produced a Customer Advising Tool which allows the basic effects of thermal mass and plan depth to be assessed. It also allows the input of window and fabric U-values, solar heat gain coefficient, infiltration rate and internal gains. This tool can be downloaded free of charge from the AUDITAC website ( index.html). The main AUDITAC website ( projekte/auditac.htm) also includes further advice on potential energy conservation opportunities (ECOs) that may be considered. The EU has now sanctioned a follow-on project to AUDITAC called HARMONAC, which will be managed by Cardiff University and include direct or indirect involvement from CIBSE, FETA, ACRIB and BRE. This project will measure the energy savings achieved from applying inspection techniques to air conditioning systems across Europe, amongst other things, with a particular focus on the UK. The project starts in September 2007 and the results and findings will be available via the website ( research/auditac/index.html) as they become available. 6 Explanatory notes for building owners and managers 6.1 Background Inspection, maintenance and cleaning programmes to maintain efficiency and to alleviate potential health hazards should be part of the normal activities associated with the ownership and operation of systems, and should often be applied more frequently than the assessment for energy efficiency described here. Owners and managers are reminded of their statutory obligations and duties of care in the operation and maintenance of air conditioning systems, and their attention is also drawn to the legislation and guidance mentioned in this section. The major reasons for undertaking maintenance could be categorised as maintaining the ability of the system to provide healthy and comfortable environments for building occupants, limiting the escape of refrigerant gases, ensuring the safety of equipment, minimising the use of energy and maintaining the value of the capital asset. The practices and procedures needed to achieve these aims will be more extensive in complex systems, much simpler in instances where a single unit air conditioner is used. It is outside the scope of this document to describe such procedures in detail, but an introduction to available professional and industry good practice guidance is included in section 6.6. It should be noted that a good practice inspection and maintenance regime would not normally include all of the issues addressed by the EPB Regulations (1). In particular, those aspects relating to the sizing of the system in relation to the cooling load, and to the provision of advice. 6.2 The inspection process The inspection process required under the EPB Regulations (1) will examine the refrigeration equipment and air movement systems that are part of air conditioning systems, and their controls. It will also examine any documentation that helps understand the systems, or indicates the extent to which the systems have been maintained. The inspector is also required to estimate whether the system is suitably sized for the cooling loads in the treated spaces, and to provide advice on ways in which improvement might be made. Access will be required to equipment that may be located in plant rooms, or outside the building including on rooftops or in other positions with limited provision for access. In all cases the building owner or manager should agree the means for safe access, in agreement with the inspector, following a health and safety risk assessment of the individual situation. The inspector may need to be accompanied by the responsible building manager or maintenance agent at all times. Some additional access is likely to be needed, for example to the inside of AHUs or ducts, which must be provided and supervised by the responsible building manager or maintenance agent with due regard to the safety of the inspector and to building occupants. As this would require the system to be turned off to allow safe access, arrangements may need to be made for this outside working hours to avoid disruption to business. Similarly, the inspector may need to access a sample of components, such as fan coil units, which may be hidden above suspended ceilings where access should again be provided by the responsible building manager. Owners and managers should not expect the inspector to routinely alert them to all hazards or aspects of the installation, operation or maintenance of systems that are unsafe. If owners or managers require this service then they should ensure that the need is clearly specified in their invitation to undertake the work, assure themselves that the inspector is competent to undertake such additional inspections, and ensure that such aspects are clearly expressed in the contract or agreement with the contractor. 6.3 The inspection report The purpose of the inspection and the resulting report are to ensure that building owners or managers are provided with basic information that gives an indication of the likely efficiency of the air conditioning systems for which they have responsibility, together with some initial advice on how energy efficiency or effectiveness might be improved. The inspection and report will benefit the owner or manager only if its findings are acted upon. All of the organisations involved in the preparation of this guidance

28 Explanatory notes for building owners and managers 21 recommend that the advice be considered, and that appropriate rectification or improvement be made where this is attractive and cost effective. Following up the advice in the inspector s report could often result in immediate improvements to the effectiveness of air conditioning systems and/or to reduction in the operating costs. In some cases the costs of providing both heating and cooling may be reduced, where it may have been identified that these two systems are unnecessarily in use at the same time due to inappropriate controls or settings. In many buildings it will be clear that the building and systems are already well understood and well maintained, and records may be available showing that the equipment has been well commissioned and is already being regularly maintained to a good standard. In such cases the inspection could be reduced in extent and the report may be brief with the main content advising on opportunities for load reduction or on alternative solutions that may not have been previously considered. However, in other cases the inspector may find it necessary to suggest relatively basic maintenance such as cleaning or repairs to equipment whose efficiency has evidently suffered through neglect. It should be noted that cleaning operations or adjustment to controls do not form part of the inspection procedure, even where they might be carried out simply and with significant immediate effect in improving efficiency. This is simply because the inspection itself is not intended, or expected, to carry out any physical work of this nature and to do so could change the level of professional risk to the inspector. Authority to carry out such work would need to be given specifically, as part of a separate arrangement by the responsible person, and where the inspector is competent to carry it out. That said, though, the owner or manager or their representative may well be able to carry out some alterations themselves as the inspection is carried out, provided they agree with the inspector s observations. Most reports are likely to contain advice between the two extremes, in that there may be a combination of simple low- or no-cost measures and measures where some investment may be required either to apply the measures, or to investigate the potential to apply measures in more detail. The manager should also be provided with, or informed how to obtain, access to advice on the ongoing management of the systems, particularly that contained in existing free publications such as the Carbon Trust s Good Practice Guides (available from co.uk). 6.4 Exchanging information with other inspection or certification procedures The inspector s report should be kept in a safe place so that it can be used to inform subsequent inspections. An ideal location would be to keep the report together with ongoing maintenance and/or energy records in a building log book. The more recent buildings may already be provided with a building log book satisfying the provisions introduced in the 2006 amendment to Building Regulations Part L (26). CIBSE TM31: Building log book toolkit (6) provides guidance and a template for the preparation of the log book, and also on its subsequent use by the building manager. The building log book would be the most suitable place to keep records of the air conditioning inspection, together with other such inspection results. Where such a log book has not already been prepared, it would be most helpful to begin a file in which to keep and use these records. In addition to the requirement to undertake regular inspection of air conditioning systems, the Energy Performance of Buildings Directive (2) and, in England and Wales, the Energy Performance of Buildings (Certificates and Inspections) (England and Wales) Regulations 2007 (1), also include requirements for the preparation of a building Energy Performance Certificate for certain building types. This is to be made available to prospective buyers or leasers of buildings, and is intended to inform them of the energy efficiency properties of the building. The Energy Performance Certificate will need to be prepared following an inspection of the building to identify key characteristics that influence the energy efficiency. These would include the building fabric properties (walls and glazing), details of the installed heating, ventilation and cooling systems, and factors influencing the loading on heating and cooling systems such as the likely heat gain from occupants and the use of energy consuming equipment in the building. Some of this information is also needed for the air conditioning inspection, and so it would be of benefit to share information between the inspections wherever possible. From July 2007 the F-Gas Regulation (9) requires regular testing for leakage of fluorinated greenhouse gas refrigerant from some systems. Some refrigeration systems containing CFC or HCFC refrigerant may already be subject to regular leakage testing under Regulation (EC) 2037/2000 (10) on substances that deplete the ozone layer. Some air conditioning installations fall under the scope of the Pressure Systems Safety Regulations 2000 (11), which may apply to systems with an input power in excess of 25 kw. The information that would be helpful to keep in the building log book, or in a separate file if a formal log book is not available, includes: the preparatory details listed in sections 2.1 (simpler packaged systems) or 3.1 (more extensive and centralised systems) a copy of the inspector s full signed report from the air conditioning inspection the preparatory details and report from any inspection carried out to provide the building energy performance certificate, and the reports of any other regular inspections (such as inspections for refrigerant leakage) involving the building s air conditioning or heating systems. Any future inspections can then be provided with this information easily, and the time needed to carry out future inspections can be minimised.

29 22 Inspection of air conditioning systems 6.5 The scope of the inspection Refrigeration Refrigeration equipment and its associated heat exchange systems are checked only briefly. The inspection looks primarily for indicators of damage or lack of maintenance that would significantly reduce their efficiency from their as new state. This is not intended to provide a high level of detail. Effective heat rejection is necessary to maintain the efficiency of the refrigeration system. If outdoor heat rejection equipment is damaged, or its access to adequate flow of air is otherwise reduced by blockage due to dirt and debris, its effectiveness in rejecting heat is reduced and its temperature will be unnecessarily high. The consequent increased temperature at the outdoor unit increases the temperature difference that the refrigeration system has to maintain, which has the effect of reducing refrigeration efficiency and reducing the cooling capacity of the system. It may cause the refrigeration equipment to turn off and on under the action of its own high temperature or pressure cut-out, often without satisfying the building cooling load. Similarly, effective indoor heat exchange is necessary to maintain the efficiency of the refrigeration system. If this heat exchange equipment is damaged, or its access to adequate airflow is otherwise reduced, is effectiveness in transferring heat to the refrigeration system is reduced and its temperature will be unnecessarily low. The consequent reduced temperature at the indoor unit increases the temperature difference that the refrigeration system has to maintain, which has the effect of reducing refrigeration efficiency, and reducing the cooling capacity of the system. It may cause the refrigeration equipment to turn off and on under the action of its low temperature or pressure cut-out, often without satisfying the building cooling load Air movement systems Where installed as part of the system to provide cooling, air movement systems are an important factor in the inspection. The contribution that fans make to the total annual energy consumption of the combined cooling system is likely to be higher than that of the refrigeration plant itself, and there may be a greater potential for improvement. The effectiveness of delivery of air can play a part in determining the overall efficiency of the air conditioning system. Where delivery systems are ineffective, plant that is otherwise efficient may operate for longer periods than necessary. However, the reverse may also be true, in that some delivery systems may interact unfavourably with occupants or with control sensors, leading to reduced operation and consequent lack of adequate cooling. Improving some systems, even at good efficiency, could increase annual energy use. Important factors to observe are the condition of, damage to, or blockage of filters and heat exchangers, and the fan type and method of control. Ventilation air delivery systems need free access to outdoor air. Where grilles, screens or pre-filters are obscured by damage or debris, additional energy will be needed to overcome the extra resistance caused by the restriction to flow, or the system may underperform in other ways due to reduced airflow rates. Where systems provide cooled air, then admitting air from locations where the local air temperature may be higher than ambient will add to the energy required to achieve cooling to the required temperature. Such locations might include positions near busy roads, in car parks, or where exhaust air from the building could be drawn into the air inlet Controls System controls are inspected in more detail. There could be considerable scope to identify inefficiency due to inappropriate control methods, incorrect control settings and poorly located sensors, and there could be much potential for improvement at low cost. Although discovered faults might be as simple as time switches or cooling or heating thermostats being incorrectly set, the inspector would not have any authority to reset them but only to report to the manager. An investigation of the realised effectiveness of system controls over any significant period of operation would be outside the scope of a simple inspection regime, but a series of physical observations of their layout and operation could give an indication of potential inefficiency, ineffectiveness or misuse. It may not be possible to investigate all aspects of the layout and operation of controls, particularly in more complex systems. However, some or all of the following important issues might be accessible to a brief examination: the set temperatures to which the treated spaces are to be conditioned the time periods during which they are to be conditioned the appropriateness of the control zones, control sensors and their locations the potential for cooling to be operated at the same time as heating the method of refrigeration capacity control the method of airflow rate control. Where systems are controlled by a building management system (BMS), it may be necessary for the building manager to arrange for relevant aspects of this information to be extracted from the BMS prior to the inspection Documentation A number of the issues to be assessed as part of the procedure may be found by examining documentation describing the installed systems and their commissioning results. As example, the specific fan power (SFP) of air supply and exhaust systems may be calculated from details of the installed plant and commissioning flowrates, for comparison with current guidance.

30 Explanatory notes for building owners and managers Maintenance Evidence is sought of any existing planned maintenance schedule, or of other recent maintenance activities. Where documentation clearly shows that equipment and systems are already the subject of regular good practice checking and maintenance procedures, a number of aspects of the required inspection and provision of advice may be omitted Advice on improvement options Three levels of practice are likely to be encountered when systems are inspected: systems where efficiency is clearly impaired due to faults, neglect or mis-use systems where efficiency is likely to be lower than currently accepted due to aspects of design or use systems that are acceptably efficient. Corresponding to these, there are three levels at which advice might be given, for example: (a) (b) (c) to advise on the rectification of faults in any system that would have impaired its efficiency from the design intent to offer improvement advice to bring existing systems broadly to a standard of inherent efficiency consistent with the minimum provisions of Building Regulations Approved Document L2 (14) to offer best practice improvement advice to raise standards even where systems are fully compliant with the current minimum provisions of Building Regulations Approved Document L2 (14). Given the need for simplicity and consistency, the approach aims to achieve a combination of aspects of (a) and (b) only. However, best practice aspects may be provided on a generalised basis by providing reference to other published guidance sources. 6.6 Good practice inspection and maintenance of air conditioning equipment The CIBSE, in common with other professional and industry bodies, recommends that air conditioning equipment be regularly inspected and maintained to good practice standards. This is considered necessary for a variety of important reasons, including: maintaining healthy and comfortable conditions for building occupants minimising loss of refrigerant gases that may damage the atmosphere or contribute to global warming ensuring the continued safe and efficient operation of the equipment and extend its life. To support these aims, a number of industry and professional bodies have developed guidance on good practice for the inspection and maintenance of most air conditioning equipment, and support training schemes to provide the technical skills necessary to carry out the work. Among these bodies, the CIBSE, the Heating and Ventilation Contractors Association (HVCA), the Institute of Refrigeration (IoR), the Air Conditioning and Refrigeration Industry Board (ACRIB) and the Sector Skills Council (Summit Skills) are widely recognised as setting the industry standard. The frequency with which air conditioning equipment should be inspected and maintained is another important factor. Manufacturers will normally recommend the particular intervals they consider appropriate for their own equipment, although this may sometimes be considered on the conservative side and others might recommend longer intervals. It must be stressed that the inspection and assessment procedures described in this document provide only an initial survey of equipment designed to alert the owner or manager to the more obvious needs to maintain or modify air conditioning systems. These inspections will only be capable of identifying instances where performance is likely to have been significantly affected, based on fairly superficial inspection and observation, and are intended to fulfil the requirements of the EPB Regulations (1). These are not a substitute for the inspection and maintenance regimes recommended by CIBSE, industry and the professions, and considered necessary for the safe and correct operation of equipment. Guidance on good and best practice inspection and maintenance of air conditioning equipment, and controls, has been published by the CIBSE and the HVCA. It includes both strategic advice for the building owner or operator, and specific detailed advice for the maintenance contractor. The CIBSE s Guide to ownership, operation and maintenance of building services (27) covers most aspects of building services maintenance both from the standpoint of the services designer and of the building owner or operator. It reviews the procurement of maintenance services and legal issues as well as providing an overview of the maintenance needs of building services systems including air conditioning systems and their controls. The HVCA s Standard Maintenance Specification for Services in Buildings (28), provides advice on the maintenance of a wide range of engineering services from the standpoint of the building services engineer. It provides advice, in checklist form, indicating the specific components that should be inspected, and the recommended frequencies of inspection for each component. It is divided into equipment categories that include the whole range of air conditioning system components and controls. Both documents are extensive, and it is not suggested that a building owner or manager should read them entirely. However, they provide useful sources of reference in planning a maintenance strategy and selecting a suitable contractor to undertake the work. They do not supplant equipment suppliers own recommendations for inspection and maintenance, which may be more demanding and which the owner or manager may consider need to be carried out in order to preserve equipment guarantees. They do provide a consensus view of standards that are

31 24 Inspection of air conditioning systems appropriate to the safe working and efficiency of systems where manufacturer guidance may be absent. Also relevant are BS 8210: Guide to building maintenance management (29), and the BSRIA AG 4/2000: Condition survey of building services (30). These documents address the whole range of building fabric and services equipment and include some general guidance on simpler inspections that would be carried out as part of asset and condition surveying, and maintenance planning. The guidance is aimed primarily at maintaining or reviewing the value of the building and its systems as assets, but includes aspects that could affect energy efficiency among the factors to be reviewed. Other information supporting the operation and maintenance of building services include BSRIA publications BG 7/2004: Business focused maintenance toolkit (31), AG 24/97: Operation and maintenance audits (32) and AG 13/99: HVAC troubleshooting a guide to solving indoor environmental and energy consumption problems (33). It is not possible, in this document, to specify the content or frequency of good practice inspection and maintenance. Such a specification should ideally be arrived at as an individual decision for the owner or manager, based on the good practice guidance described above, additional relevant guidance that may have been provided by particular equipment suppliers, and the specific aims and needs of the organisation. However, at a minimum, the owner or manager seeking good practice maintenance of air conditioning systems may specify more simply by asking organisations to quote for maintenance to the HVCA s Standard Maintenance Specification for Services in Buildings (28), for the relevant equipment. Organisations should also be asked to demonstrate that their personnel are suitably qualified to undertake work of that nature. References 1 The Energy Performance of Buildings (Certificates and Inspections) (England and Wales) Regulations 2007 Statutory Instruments 2007 No. 991 (London: The Stationery Office) (2007) 2 Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002 on the energy performance of buildings ( The Energy Performance Directive ) Official J. of the European Communities L1/65 ( ) (Brussels: Commission for the European Communities) (2003) 3 BS EN 15240: 2007: Ventilation for buildings. Energy performance of buildings. Guidelines for the inspection of air-conditioning systems (London: British Standards Institution) (2007) 4 Conservation of fuel and power in buildings other than dwellings Building Regulations 2000 Approved Document L2 (London: The Stationery Office) (2002) 5 Building energy metering CIBSE TM39 (London: Chartered Institution of Building Services Engineers) (2006) 6 Building log book toolkit CIBSE TM31 (London: Chartered Institution of Building Services Engineers) (2006) 7 Building log books a users guide Good Practice Guide GPG348 (The Carbon Trust) (2003) (available from carbontrust.co.uk) (accessed June 2007) 8 Energy efficiency in buildings CIBSE Guide F (London: Chartered Institution of Building Services Engineers) (2004) 9 Energy assessment and reporting method CIBSE TM22 (London: Chartered Institution of Building Services Engineers) (2006) 10 Regulation (EC) No. 842/2006 of the European Parliament and of the Council of 17 May 2006 on certain fluorinated greenhouse gases ( The F-Gas Regulation ) Official J. of the European Union L161/1 ( ) (Brussels: Commission for the European Communities) (2006) 11 Regulation (EC) No. 2037/2000 of the European Parliament and of the Council of 29 June 2000 on substances that deplete the ozone layer Official J. of the European Communities L244/1 ( ) (Brussels: Commission for the European Communities) (2000) 12 The Pressure Systems Safety Regulations 2000 Statutory Instruments 2000 No. 128 (London: The Stationery Office) (2000) 13 Non-Domestic Heating, Cooling and Ventilation Compliance Guide (London: The Stationery Office) (2006) 14 Conservation of fuel and power in new buildings other than dwellings Building Regulations 2000 Approved Document L2A (London: NBS/RIBA Publications) (2006) 15 Environmental design CIBSE Guide A (London: Chartered Institution of Building Services Engineers) (2006) 16 Knight I and Dunn G UK Office Air Conditioning Energy Profiling Study Final Monitoring Report, Toshiba Carrier UK Ltd. (Cardiff: Welsh School of Architecture) (2003) 17 Eurovent Certified Performance (website) (Paris: Eurovent- Cecomaf) ( (accessed June 2007) 18 Heating, ventilating, air conditioning and refrigeration CIBSE Guide B (London: Chartered Institution of Building Services Engineers) (2001 2) 19 Means of ventilation Building Regulations 2000 Approved Document F (London: NBS/RIBA Publications) (2006) 20 Rules of Thumb (4th edn.) BSRIA BG 14/2003 (Bracknell: BSRIA) (2003) 21 Enhancing the performance of oversize plant BSRIA AG1/2000 (Bracknell: BSRIA) (2000) 22 Code for lighting (London: Society for Light and Lighting) (2006) 23 Daylighting and window design CIBSE LG10 (London: Chartered Institution of Building Services Engineers) (1999) 24 Free cooling systems BSRIA BG8/2004 (Bracknell: BSRIA) (2004) 25 Energy Technology List (website) (London: Department for the Environment, Food and Rural Affairs) ( etl) (accessed June 2007) 26 The Building Regulations 2000 Statutory Instruments 2000 No. 2531, as amended by The Building (Amendment) Regulations 2001 Statutory Instruments 2001 No and The Building

32 Appendix A1: Suggested reporting format for a packaged cooling system 25 Appendix A1: Suggested reporting format for a packaged cooling system Report of packaged cooling system inspection Organisation Address Building owner/manager ABC Designs Ltd. 123 Any Street, Anytown, AA1 1AA [name] (Chief Executive) Name of inspector Date of inspection [name], for XYZ Inspection Services Ltd. 1 August 2006 Equipment inspected Equipment Unit XX: [Manufacturer s name] [model] multi-split package, serial number [number]. Rated cooling capacity 11 kw. Unit YY: [Manufacturer s name] [model] single split package, serial number [number]. Rated cooling capacity 7.5 kw. Location Unit XX: outdoor unit located on 2nd floor. Unit YY: outdoor unit located on ground between car park and south wall of building. Areas served Unit XX: serves 4 offfices on 2nd floor by 4 ceiling mounted cassettes. Offices have openable windows. Unit YY: serves 1st floor combined office and reception area by single perimeter mounted unit. Area has openable windows. Inspection of documentation and records Equipment list Temperature control Time control Maintenance regime Controls and sensors Metering Loads Issues Available as catalogue data for units XX and YY. Locations of indoor and outdoor components as noted above. Included in manufacturer s catalogue information. Units XX and YY: temperature control included in unit controllers. Included in manufacturer s catalogue information. Units XX and YY: time control included in unit controllers. Both units operating on manual override of inbuilt time controls. Units XX and YY: records include reports of 3-monthly maintenance visits. Filters last replaced 22 Feb No reports of refrigerant leakage testing or re-charging. Units XX and YY: controls integral to units and included in routine maintenance. Sensors remote, wall mounted. Capacity control by variable speed rotary compressor. None. No record of design loads. Systems have been retro-fitted to mitigate effects of solar gain. System YY in reception area thought to over-cool around midday.

33 26 Inspection of air conditioning systems Inspection of equipment: system documentation Checklist reference Observations and advice PS1.1 PS1.2 PS1.3 PS1.4 PS1.5 Plant location Maintenance regime Plant size in relation to cooling load Usage / metering Proximity to heat sources Plant located as described. For clarity, maintenance engineer should be asked to state on future records when leakage testing and other observations have been made, even where the results are negative. Unit XX: 4 offices each approx 5 m x 4 m, 30% glazed on long face (south facing), each office has 3 occupants, 3 PCs, 1 laser printer. Approximate cooling load office (rule of thumb for perimeter areas, office activity): 110 W/m 2 x 80 m 2 = 8.8 kw. Installed size = 11 kw. Sizing of unit XX considered appropriate to present load. Consider smaller unit on replacement if solar control measures noted below are adopted. Unit YY: combined office/reception area, approx 7 m x 4 m, 30% glazed on long face (south facing), 4 occupants, 4 PCs 1 laser printer, 1 copier/fax. Approximate cooling load (rule of thumb as above) 110 W/m 2 x 28 m 2 = 3.1 kw. Installed size = 7.5 kw. Sizing of unit YY is high in relation to present load (although means of capacity control maintains high efficiency at reduced loads). Consider smaller unit on replacement, particularly if solar control measures noted below are adopted. No metering or records: Consider installing hours run or energy meters to monitor use of systems. No heat sources located near outdoor units. Inspection of equipment: outdoor and indoor units Checklist reference Observations and advice PS2.1 PS2.2 PS2.3 PS2.4 PS2.5 Usage / metering Outdoor units Signs of leakage Operation Obstructions to airflow: (a) outdoor units (b) indoor unit grilles/filters No metering or records: Consider installing hours run or energy meters to monitor use of systems. Plant located as described. Outdoor units are generally clear of traces of oil or other signs that might indicate leakage. No gauges fitted. Units brought into operation provided reasonable temperature difference between indoor and outdoor units. Unit XX (rooftop) has free access to air. Planting near unit YY (near car park wall) is in danger of over-growing the unit, and leaf shedding has partially blocked the outdoor heat exchanger. Recommend immediate clearing of the heat exchanger surface, and cutting back the planting to reduce future risk. Condition of the outdoor unit should be observed more frequently and unit maintained in clean condition. Grilles appear clean and maintenance records show filters last replaced 22 Feb Airflow appears satisfactory

34 Appendix A1: Suggested reporting format for a packaged cooling system 27 Inspection of equipment: system controls Checklist reference Observations and advice PS3.1 PS3.2 PS3.3 PS3.4 PS3.5 PS3.6 PS3.7 Zoning Control time setting Control periods Control sensors Set temperatures Opening windows Equipment age and method of capacity control Units have been installed in areas where overheating has been an issue in the past, and the application seems appropriate to the need. Not applicable. Units on fully manual control. Not applicable. Units on fully manual control. Unit XX: remote sensors appropriate. Unit YY: remote sensor in reception area receives full sunlight between 11 am and 3 pm and so is likely to cause overcooling during these periods. Suggest re-locating sensor to permanently shaded wall surface near reception desk. Unit XX: set temperatures in all zones is 19 C. Suggest these could be reset to 22 C or higher, or altered depending on outdoor temperature. This will reduce energy consumption while unit is operating, and reduce operating periods. Unit YY: set temperature is 24 C, as excessive cooling had been experienced around midday. Excessive cooling likely to be caused by sensor position, and relocating as suggested should improve control of temperature. No written guidance on window opening and use of cooling equipment provided. Units XX and YY are about 7 years old, and use variable speed rotary compressors providing efficient capacity control. Summary of advice Item PS1.3 PS1.4 PS1.5 PS2.4 PS3.4 PS3.5 Maintenance Sizing Usage/metering Obstructions to airflow: (a) outdoor units Control sensors Set temperatures Observations and advice Ask the maintenance engineer to state on future records when leakage testing and other observations have been made, even where the results are negative. When replacement becomes necessary, consider smaller capacity units if measures have been adopted to control solar gain. Consider installing hours run or energy meters to monitor use of systems. Clear overgrowing planting from the outdoor heat exchanger of (unit YY) and cut back the planting to reduce future risk of obstruction. Observe the condition of this outdoor unit more frequently and maintain in clean condition. Consider re-locating sensor of unit YY to permanently shaded wall surface near reception desk. Consider resetting control for unit XX to 22 C or higher, or altering depending on outdoor temperature. If sensor for unit YY is re-located as suggested, consider the same set temperature as unit XX.

35 28 Inspection of air conditioning systems General observations and advice for load reduction or alternatives Unit XX appears to have been installed to reduce effects of solar gain in south facing general office areas which otherwise have low internally generated heat gain. As an alternative the degree of overheating could be reduced by installing solar shading, preferably external to windows. Overhangs (brise soleil), external solar control window film, or movable external shades (blinds) are likely to be the more effective, in conjunction with increased ventilation through window opening, in minimising use of systems. The practice observed in some offices of operating the cooling system with windows also open is very inefficient and ineffective and should be strongly discouraged. Unit YY also appears to have been installed to reduce effects of solar gain, primarily in the reception area which has otherwise low levels of internally generated heat gain. Although oversized, the method of capacity control should maintain good efficiency at relatively low load. Signature of inspector Date