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.