Manual A - For Building Operators

Transcription

1 Par Hill Research Reducing air pollution from your building - a series of manuals for operators, designers & developers Manual A - For Building Operators Joanne Arbon & Iarla Kilbane-Dawe

2 Reducing air pollution from your building Manual A for building operators Some important conventions used in this document Key information is highlighted in an orange box like this text. This series of guides to reduce air pollution from your building comprises Key reference documents or websites look like this Manual A - for building operators Manual B - minimising air pollution from new developments 5 key questions about air pollution and buildings - 1 page guide Keywords and definitions are shown in blue bold typeface. Examples and Case Studies These are shown inside a light blue box. 2 - Reducing air pollution from your building

3 Contents Introduction & reading guide 4 A1 Laws and regulations 6 A1.2 Building Regulations requiring conservation of energy 6 A1.3 EPCs and DECs 8 A1.4 The law and air pollution from buildings 9 A1.6 BREEAM & LEED 10 A1.7 Health & Safety 11 A2 Maximise energy efficiency before addressing demand 12 A2.2 Audit the heating & cooling demand in your building 13 A2.3 Implement a heating & ventilation strategy 14 A2.4 Review and improve your building fabric 16 A2.5 Distribution of the heat and cooling 17 A2.6 motors, pumps, drives & fan 18 A2.7 Building Information Modelling 18 A2.8 Metering, monitoring, targeting & building management 19 A2.9 Organisational & Behavioural change 20 A3 Know your heating & cooling requirements 21 A3.2 Calculating Heat Load/Demand 21 A3.3 Rules of Thumb 21 A3.4 Simple sizing Calculation 22 A3.5 Multiple & Modulating Boilers 24 A4 Fuel choice & pollution 25 A4.1 Air pollution and heating system choice 25 A4.2 When is it cost-effective to replace a boiler? 25 A4.3 Select the correct heat supply 26 A5 Best practice for heating control 27 A5.1 Introduction 27 A5.2 Boiler controls 28 A5.3 Time controls 29 A5.4 Temperature controls 29 A5.5 Building Management Systems 30 A5.6 Getting the best out of your controls 31 A6 Best practice for maintenance 32 A7 How to develop a business case for better equipment 34 A7.1 Introduction 34 A7.2 Justifying the investment 34 A7.3 Good Practice In Determining Costs & Benefits 35 A7.4 Simple methods of comparing costs and benefits 36 A7.5 Comparing costs & Benefits 37 A7.6 Whole Life Cost Assessment 38 A7.7 Ease And Effect 38 A7.8 IPMVP Reducing air pollution from your building

4 Introduction Almost all buildings emit air pollution due to combustion in their heating, cooling or electricity generation systems. While there s a lot of attention paid to carbon (CO 2 ) emissions from buildings that accelarate global warming, up to now the toxic air pollution from buildings has received less attention. In fact buildings account for as much as half of some air pollutants emitted in London. Buildings tend to cause the background air pollution in cities when this combines with the vehicle exhaust along roads it can create hotspots where air pollution concentrations both pose a threat to health and breach legal limits. This is a significant problem for public health. In London the Department of Health has attributed about 4,000 premature deaths a year to Particulate Matter (PM) pollution. PM is a type of soot whose very fine particles get deep into people s lungs and pass into the blood, causing and exacerbating all sorts of health problems, including cancer. Buildings also emit Nitrogen Dioxide (NO 2 ), usually in much larger amounts than PM. This is associated with increased hospital admissions and deaths from heart failure. Reducing air pollution from buildings not only improves people s health, but it also tends to save money as a central task in minimising air pollution is energy efficiency. HOW TO MINIMISE AIR POLLUTION FROM BUILDINGS The main regulations applying to air pollution from buildings can usually be complied with if two key actions are taken. First, the demand for onsite heat and electricity consumption in the building should be minimised. In other words, the building should be operated to be as energy efficient as possible, at The central principles of reducing air pollution from buildings 1. Design the building to maximise energy efficiency. 2. Use low polluting systems to meet the remaining energy demand. least to the latest Part L standards and ideally better than these. This has the effect of reducing the demand for heat and electricity generation services that emit air pollution. Second, as far as possible use low polluting services to generate heat and - if required - power. These need not be exotic or expensive - conventional high efficiency or condensing gas boilers are the ideal solution in many cases, in particular the ultra low NO x variants. But renewable options exist too, like heat pumps, solar hot water and solar PV/electric panels. All are supported by government incentives. This dual approach will also help your building approach or achieve standards like the zero carbon building or BREEAM. This document covers seven of the main areas to help you operate your building to minise it s air pollution emissions, including: Legislation & regulations, which explains how the Building Regulations and local air pollution regulations interact How to maximise your building s energy efficiency Some simple methods for estimation of heating and cooling demand Heat and energy services, how much they pollute and which to use The main types of boiler and heating controls you should use to ensure the heat and energy services are used optimally and efficiently. Best practice in maintenance Building a business case to improve your energy efficiency and plant This information will help you ensure your building respects the local environment and public health and your fuel cost are minimised. 4 - Reducing air pollution from your building

5 Reading guide for this document Read A3 understand demand Yes BEGIN HERE: Is your boiler more than 15 years old? No Is the boiler / heating system correctly sized? No Is heating plant in good condition & running efficiently? Yes Yes Is the plant regularly & proactively maintained? Yes Read A1 Consider all other energy efficiency options before replacing the heating system No No Is the heating system uncontrolled? Yes No Read A4 & A7 consider upgrading to a new boiler Read A5 consider fitting boiler or building control systems Read A6 Review Best Practice in Maintenance 5 - Reducing air pollution from your building

6 A1 Laws and regulations A1.1 Introduction It s always essential to know the rules and regulations that govern the management of buildings, boilers, or HVAC systems. The main regulations that affect a building s air quality performance are those that govern energy efficiency and those relating to air quality nuisance. In general, buildings that are more energy efficient will emit less air pollution if certain fuels and systems are avoided (more in Chapter A5). Therefore much of this Factsheet discusses the energy efficiency regulations for buildings and when they create opportunities for more energy efficiency and less air pollution. We ll cover: When Part L of the Buildings Regulations affects building management; EPC & DEC Certificates, and EcoDesign of new building devices; Air Quality regulations & nuisance enforcement; The BREEAM and LEED voluntary standards; Health & Safety Regulations. A1.2 Building Regulations requiring conservation of energy Part L of Building Regulations is essential (if unexciting) reading for building managers. Part L, as it s commonly known, requires conservation of fuel and power, prerequisites for minimising air pollution from buildings. Since 2000, Part L has greatly increased the energy efficiency requirements of new buildings or replaced or refurbished systems. Those required today are about Examples of guidance in the Building Regulations Part L Non-Domestic Buildings Compliance Guide Recommended minimum seasonal efficiency for existing boiler systems Fuel type Effective boiler seasonal efficiency* Boiler season efficiency* Natural Gas 84% 82% LPG 85% 81% Oil 86% 84% * Gross calorific value Recommended minimum controls package for replacement boilers in existing buildings Minimum Controls Suitable Controls Package a. Zone control and Zone control is required only for buildings where the floor area is greater than 150m2. As a minimum, on/off control (e.g. through an isolation valve for unoccupied zones) should be provided. This is achieved by default for a building with a floor area of 150m2 or less. b. Demand control, and Room thermostat which controls through a diverter valve with constant boiler flow water temperature. This method of control is not suitable for condensing boilers c. Time control Time clock controls 80% more efficient than the average UK building stock. Combined with ultralow NO x boilers or other low emission energy systems, this can lead to great reductions in air pollution from new buildings compared to the current building stock. Though Part L only states general requirements, it is supported by Approved Documents. These set practical guidance on how to meet Part L, 6 - Reducing air pollution from your building

7 When existing buildings systems must be upgraded to the current Part L Buildings of 1000m 2 or more must be fully upgraded to the current Part L standard when certain changes are being made this is known as Consequential Improvements. This must be done when: The building is undergoing material change of use. There is new provision of fixed building services or an increase to the overall capacity of the current fixed building services; When thermal elements are replaced or renovated, they must be upgraded in its entirety to comply with Part L. This includes the following requirements: When new or upgraded services are being installed, any changes to controlled fittings or services must include specification of efficient boilers, pipe-work & controls. This includes space heating and hot water systems, mechanical ventilation and cooling systems. Duct leakage and fan performance testing must be conducted. Provision for energy metering, including differential monitoring between systems. An instruction manual for building users must be provided for heating, cooling and ventilation systems to enable them to realise the optimum levels of energy efficiency to which their buildings & any new systems are designed. This also applies to any extensions to properties with floor area greater than 1000m 2, if the planned extension is greater than 100m 2 in area and greater than 25% of the existing useful floor area. as in the examples above. Existing buildings, and parts thereof, are only required to be upgraded to Part L standards when certain changes occur, 7 - Reducing air pollution from your building such as when a boiler is replaced. The full list of these conditions is given above. For existing buildings energy conservation upgrades are only required for the elements that are to be substantially replaced or renovated, they do not apply to normal maintenance or repairs. The Part L Non-Domestic Buildings Compliance Guide sets recommended minimum energy efficiency standards for compliance with building regulations for each building service. This includes the minimum controls packages required, efficiency testing methods and installation requirements, as well as suggestions to improve plant efficiency. Summary of Part L Legal Requirements Part L requires conservation of fuel and power in buildings through all three of insulation, energy systems and buildings management and information. The legal requirements are that reasonable provision shall be made for: (a) limiting heat gains and losses through thermal elements and other parts of the building fabric; and from pipes, ducts and vessels used for space heating, space cooling and hot water services; (b) providing fixed building services which are energy efficient, have effective controls, and are commissioned by testing and adjusting to ensure they use no more fuel and power than is reasonable in the circumstances; (c) providing sufficient information to the owner about the building, the fixed building services and their maintenance requirements so that the building can be operated in such a manner as to use no more fuel and power than is reasonable in the circumstances. The Approved Document (Part L) for energy efficiency in existing buildings that are not dwellings is (L2B). Part L nondomestic compliance guide on

8 A1.3 EPCs and DECs show your buildings energy performance The Energy Performance of Buildings Directive (as transposed into UK law) requires regular inspections of heating and air conditioning plant to ensure that they are operating correctly full details are given in the box on the right. It also requires that buildings must have a current EPC certificate when constructed, sold or rented out. Public buildings larger than 500m 2 must be certified annually on the basis of actual energy performance and the resulting DEC must be displayed. The rating achieved in these certificates will be strongly influenced by heating system choice and performance, so keeping a regular maintenance schedule for energy systems is important. The Eco-Design Directive sets the minimum energy performance standards of a wide range of products to be sold/used in Europe and in coming years it will require that many energy consuming devices used in buildings are more efficient, including boilers, computers, televisions, transformers, industrial fans, industrial furnaces. Other energy related products (ERPs) which do not use energy but have an impact on energy and can therefore contribute to saving energy, such as windows, insulation material, shower heads, taps etc., will also be improved by the regulations. EPC Energy Performance Certificates show the designed and calculated energy efficiency of property on a scale from A (most efficient & lowest carbon emissions) to G (most efficient & lowest carbon emissions). Main regulations on Building Energy Efficiency If selling or letting a property you must ensure that the EPC is up-to-date. Every year, ensure that the DEC has been independently certified. A key part of the audits required as part of the EPC & DEC production is provision of advice on boilers and air-conditioning systems. The advice given is in the form of checklists and recommendations developed in conjunction with the heating and hot water manufacturing and installation industries. The checklists have been designed to be simple and quick to complete, and the intention is that they are left on site. The advice can also be included in existing service and maintenance visits and now forms part of industry recommended good practice guidelines. Energy Performance of Buildings Directive (EPCs & DECs) Eco-Design at DG Ent DECs Display Energy Certificates are similar to an EPC but are based on actual performance and must be updated annually. 8 - Reducing air pollution from your building

9 A1.4 The law and air pollution from buildings There are strong interactions between government policies on sustainable buildings, building energy efficiency and air quality. Most new social housing is required to meet Level 4 of the Code for Sustainable Homes (BREEAM for homes), which specifies high levels of insulation and the installation of an ultralow NO x boiler (these are available at little or no extra cost). The government s tightening of Part L aims to reduce dramatically the carbon emissions through using less fuel, with consequent improvements in NO x and PM emissions. But they can also have a negative impact on air pollution if developers use biomass boilers or poorly planned Combined Heat and Power instead of fabric energy efficiency to achieve the Target Emissions Rate of CO 2. Use of biomass fuels is forbidden by many urban Supplementary Planning Documents (SPDs). More detailed information on planning and air quality is provided in the IES Air Quality and Planning Law briefing (reference to be found at right). Transport emissions and Low Emission Strategies As with direct building emissions, transport emissions must also be minimised. This is an extensive topic in its own right, but there are many tools and resources than can help, in particular the Low Emission Strategies (LES) website and toolkits. LES aims to help you plan transport so that demand for polluting transport is minimised and so you can help offset any emissions from your building through better transport options. Pollution abatement In Air Quality Management Areas heating system options can be increased by using abatement technologies that reduce the NO x and PM emissions of what would otherwise be more polluting systems. For each fuel and burner there are several approaches to pollutant reduction both inside the boiler and by treating the boiler exhaust gases. In addition, flue and stack heights can be increased to reduce or prevent flue gases reaching the ground or surrounding buildings. This all requires careful planning as the concentration of air pollution at receptors where people might be exposed depend strongly on the shape of the building, the surrounding buildings and the terrain itself. IES Air Quality & Planning Law (2013) is an excellent Introduction to the the topic by two legal experts. The Low Emission Strategies website contains advice, guidance and tools to help reduce transport emissions Reducing air pollution from your building

10 A1.5 London s Supplementary Planning Guidance The London Plan places several air quality requirements on new deveopments and these are elaborated in London s Sustainable Design and Construction SPG. Overall this is intended to encourage walking and cycling, high energy efficiency buildings and use of ultra-low NOx boilers or zero emission heating. The SPG covers the following main areas. Air quality assessments needed for many developments Detailed air quality assessments must be conducted for any building in an AQMA, that is likely to cause or worsen an exceedence of the Limit Values, or expose sensitive individuals to higher pollution or that involves biofuels or CHP. Air Quality Neutral Requirement To prevent further deterioration of London s air quality, benchmark maximum emissions per square meter of floor area have been set for different land use classes, both for the buildings emissions and related transport. If exceeded the developer must offset the emissions through another local activity. Combustion, especially Combined Heat & Power and biofuels The SPG sets standards for NO x and PM emissions from combustion, CHP and biomass in new buildings. These require use of ultra-low NOx boilers where feasible and appropriate abatement for the technology in use, and set maximum emissions levels for different combustion technologies, depending on whether they are in an AQMA or place where Limit Values are exceeded. London s Supplementary Planning Guidance A1.6 BREEAM & LEED BREEAM and LEED are the two main certification schemes used to improve sustainability within commercial building design and operation. While currently voluntary, the public sector demands their use and there is growing demand within commercial sectors to both improve Corporate Social Responsibility (CSR), attract funding and provide genuine evidence of sustainability within an organisation. Different building types have tailored assessment schemes, such as healthcare, industrial, offices, retail and higher education; and both now have in-use assessment schemes for certification of existing buildings. The assessment schemes are credit based assessment systems covering the all aspects of a building s operation. Choice of HVAC system and distribution services, together with levels of control and management can significantly influence the score and ratings achieved. The In-Use schemes are selfassessment based, followed by certification from an independent auditor. BREEAM Building Research Establishment s Environmental Assessment Methodology. UK Based sustainable building design standard. LEED Leadership in Energy and Environmental Design. US Based sustainable building design standard. Corporate Social Responsibility (CSR) is a form of corporate selfregulation whereby a business monitors and ensures its active compliance with the spirit of the law, ethical standards, and international norms. BREEAM In-Use LEED O&M Reducing air pollution from your building

11 A1.7 Health & Safety There is a plethora of health & safety related guidance that has implications mainly on the operation, settings and control constraints of building services. In addition the level and expertise required in system maintenance, and H&S requirements surrounding this, may also influence system choice as significant H&S requirements would push up overall system maintenance costs. Because these vary greatly by sector, it s important to conduct research into the H&S requirements for your sector before taking choosing HVAC systems. The conditions common to most sectors that you need to be aware of are: Thermal conditions o Requirements for internal temperature bands, dependent upon working environment, with recommended maxima and minima typically, 18 C and 24 C respectively for the normal population. For the very old and very young is the minimum recommended temperature 20 C. The minimum allowable working temperature is 16 C, with 13 C allowed in areas where there is extreme physical activity if personal protective clothing is provided. There are no upper limits for those at very hot conditions but medical supervision may be needed for those working up to 50 C. Air quality & Ventilation Part L of the Building Regulations requires designers to include standards of air tightness to minimise air infiltration and minimum energy efficiency standards for air conditioning and mechanical ventilation equipment. The minimum fresh air ventilation is currently 10 L/s per person. HSE Guidance note PM5 requires that hot water boilers should have an automatic control device to cut off fuel to the burners of gas-fired plant when the boiler flow outlet temperature rises to a predetermined temperature that might be unsafe. To comply with this recommendation, the minimum system pressure should be determined from the maximum design flow temperature. o o o o For energy considerations regulations forbid heating equipment at rooms above 19 C. Hot water must be stored at 60 C or higher to avoid legionella; Requirements for humidity levels. CIBSE recommends 40 70% RH for normal conditions in buildings. The target value for design is 60% RH. Requirements for max temperatures of heat emitters; CIBSE TM40 Health Issues in Buildings More specific guidelines are provided for institutions such as prisons, hospitals, schools, and care homes. HSE Guidance on Sick Buildings, Thermal Conditions & Risk Reducing air pollution from your building

12 A2 Maximise energy efficiency before addressing demand A2.1 Introduction As described earlier, the first step in minimising air pollution from a building is to maximise energy efficiency, which has the obvious benefit that it also saves money for your organisation. It s also clear from many studies that implementing energy efficiency is usually a cheaper option than replacing a heating system, so implementing these measures can allow you to defer expensive plant upgrade to future years. The evidence also shows that when those replacements become inevitable, and the needs of the latest Part L have to be met in the refurbishment, the lowest cost strategies for this involve first maximising energy efficiency measures before replacing HVAC plant. Another good reason to maximise energy efficiency before replacing plant is that is helps increase the accuracy of the business case for the new plant, which can be critical for business case development and financing. This is The eight categories of energy efficiency measures There are eight major activites where energy efficiency can be improved: 1. Auditing the heating & cooling demand in your building 2. Have a heating and ventilation strategy 3. Review the building fabric 4. Review how the heat (or cold) is distributed 5. Review motors, pumps, drives & fans 6. Consider modelling your building 7. Metering, Monitoring & Targeting and Building Management 8. Implement behaviour change measires because inefficient designs and systems are often difficult to model. For example, reductions in heat loss from plant rooms may eliminate the need for localised chilling. On the following pages, we summarise eight different approaches to improving energy efficiency, under the categories measures: Understand the heating & cooling demand in your building Have a heating and ventilation strategy Review the building fabric Review how the heat (or cold) is distributed Review motors, pumps, drives & fans Consider modelling your building Metering, Monitoring & Targeting and Building Management Implement behaviour change measures Chapters A5 and A6 on controls and maintenance will also be helpful Reducing air pollution from your building

13 A2.2 Audit the heating & cooling demand in your building Performing a heating/cooling energy audit before you begin other actions means you ll understand where energy is being consumed, and allow you to more effectively identify opportunities for reducing demand primarily before needing to consider heating upgrade/replacement options. Some easy wins can be identified through this process, such as identifying areas that are overheated as a result of incorrect thermostat or BMS settings; identifying areas where heating and cooling are in direct competition because deadbands have not been set, or that the heating and cooling services are not fully understood by the occupants. One very common misperception that heating/cooling capacity is inadequate is often undermined at this point too. Auditing can eliminate any need for capital expenditure Understanding how and when heating and cooling load is actually required, and gauging the potential to reduce overall demand can often result in there no longer being any need to replace or upgrade heating and cooling provision. For example, identifying that a high load arises from a bay loading area because loading doors are left open 24/7 which could be closed the majority of the time. This type of audit will also allow you to establish your baseline, which you can then use as an evidence base for any actions that you subsequently undertake to reduce demand. An energy audit is an inspection of the energy dynamics within a building i.e. Where, when and how energy is used and identifying opportunities to reduce this consumption. The audit may also assess the efficiency, physical condition, and programming of mechanical systems such as the heating, ventilation, air conditioning equipment, and thermostat. Audits can range for a simplistic, helicopter view walk around a site, down to in-depth, complex measurements of services. Do your own energy audit using Carbon Trust Guide CTG Reducing air pollution from your building

14 A2.3 Implement a heating & ventilation strategy Rethinking the overall provision of and need for heating and cooling within your building should be the priority. Passive Design and Heat Recover are two key measures to consider to reducing overall heat demand identified in an audit: Passive design There are often opportunities within existing buildings to incorporate elements of passive design, by switching off unnecessary heating and developing a ventilation strategy to distribute and even out temperature variations within the building. More generally, passive design uses the sun along with ventilation so that nature provides the majority of fresh air and temperature requirements. As simple as it sounds, natural ventilation relies on air flow through openings of a room or building, preferably from opposite sides. It also applies to rising hot air being replaced with cooler air sucked in through windows or vents from a lower level. Obviously, passive design and ventilation are best considered at building design stage, but don t rule out using them instead of HVAC. Some examples of passive design heating systems Natural Ventilation is simple and very cost effective Making the most of natural ventilation is a simple and cost-effective way of achieving big savings, and can significantly reduce heating and cooling loads: Passive solar heating should be considered for use in circulation spaces such as lobbies and atria, hallways, break rooms, and other types of spaces with low internal heat gain that afford occupants the flexibility to move out of the sun. There are likely to be opportunities for cross-ventilation whereby windows or vents can be closed in hot spot areas, and opened in cooler/higher level areas to enhance air movement. Finally, reduce internal heat gains, for example by sourcing it provision into a separate, sealed area, and introducing thin client technology for computer systems.. Window designed to allow more heat from the sun and the collection of solar energy through south-facing windows Storing this heat in "thermal mass," comprised of building materials with high heat capacity such as concrete slabs, brick walls, or tile floors. The natural distribution of the stored solar energy back when required, through the mechanisms of natural convection and radiation The use of trombe walls, a sun-facing wall separated from the outdoors by glass and an air space, which absorbs heat from the sun and releases it selectively towards the interior at night; and solar corridors/conservatories. Heating & cooling recovery Heat recovery is the collection and re-use of heat (or cooling) arising from any process that would otherwise be lost. The addition of heat recovery means that some of the heat contained within the extract air can be recovered. The heat energy is passed into the incoming fresh air effectively pre-heating it and meaning the boiler needs to add less heat. The two air streams need not mix directly to allow the transfer of heat. This is often well suited to ventilation systems bringing cool fresh air into a building using fans in air handling units (AHUs), or for pre-heating in boiler or hot water heating circuits. It is often low grade heat recovered, so cannot be used as a primary heat provision mechanisms (also visit section A1.6 for rules on hot water and legionella) Reducing air pollution from your building

15 Waste heat from the following common sources often presents opportunities for cost-effective heat recovery: Ventilation system extracts Boiler flue gases & blow down Air compressors Refrigeration plant High temperature exhaust gas streams from furnaces, kilns, ovens and dryers Essentials of heat recovery Heat recovery is far more efficient when the heat source and heat sink are are physically close together and occur at the same time. Heat recovery can help to stop conflicts between heating and cooling requirements which are often observed in commercial buildings. In order to assess the potential for heat recovery, a simple investigation into the air temperatures and the flow rate in the extract will allow an estimation of the payback of any heat recovery system that could be installed. Hot liquid effluents Power generation plant Process plant cooling systems Common uses (or 'sinks') for the recovered low grade heat include: Pre-heating combustion air for boilers, ovens, furnaces, and so on; Pre-heating fresh air used to ventilate the building; Hot water generation, including pre-heating boiler feed water; Space heating; Drying; Other industrial process heating/pre-heating; Payback in simplest terms this is the amount of time that is taken for the savings resulting from this investment to pay back the up front cost. Most commercial organisations tend to only consider investment in items with a payback of less than 3 5 years. Air handling units (AHUs) are devices used to condition and circulate air as part of a HVAC system. An air handler is usually a large metal box containing a blower, heating or cooling elements, and filters. Ahus usually connect to a ductwork system as the heating and cooling distribution network. The Carbon Trust Heat Recover Guide provides lots more information: Reducing air pollution from your building

16 A2.4 Review and improve your building fabric A thorough review should be undertaken of all building fabric elements which separate the indoor environment from the outdoors. This includes floors, walls, roof, windows and doors. Identify opportunities for upgrading the levels of insulation and air tightness within each of these elements, to minimise heat lost within the building. Apply building maintenance good practice Once your review is complete, good practice building maintenance should be put in place to ensure that any gaps and issues within building openings (doors/windows) are readily identified and fixed. Install or improve roof & cavity wall insulation Upgrading or installing roof and cavity wall insulation is often considered one of the most cost and energy effective measures for reducing heat loss. Up to 35% of heat is lost through un-insulated roofs and walls. Solid wall and curtain walling insulation can be more costly, however there may still be a good business case for installation particularly if it results in lower sizing of replacement heating plant. As a guide, cavity wall insulation would bring the u-value of an un-insulated cavity masonry wall down to 0.45w/m2k. While cavity wall insulation does not of itself trigger Part L(2B), it will have to be upgraded to 0.28w/m2k if any finished surfaces are to be renewed. And roof insulation should aim to achieve 0.18w/m2k. Eliminate draghts Reduce air infiltration further by installing draught proofing or sealant. Once installed this should also be checked regularly to ensure that it has not deteriorated. This is also a low cost measure, although the level of savings can be less effective particularly as they are often taken in higher comfort levels for the occupier, who may previously have sat in a draught. Use Life Cycle Analysis to determine the whole environmental impact of the building see Chapter 6 With all remedial insulation strategies, life cycle analysis should be used to determine the materials and methods which have the lowest environmental impact, taking into account the expected life of the building. Install double or triple glazing Replace glazing components if they are of poor quality, particularly if they are single glazed, sash or metal framed. Part l2b advises that windows with a u- value worse than 3.3w/m2k should be replaced, and upgraded to a minimum u-value of 1.8w/m2k. It is also worth considering the use of triple-glazing, and low-emissivity glazing. Install solar film or solar blinds If the building suffers from a large amount of solar gain, it is worth exploring opportunities for introducing solar film or integral blinds to reduce the cooling load in the winter again this can impact significantly upon heating/cooling plant sizing. The u-value is the rate of heat transfer or heat loss, in watts, through one square metre of the buildings fabric, divided by the difference in temperature across that element of the structure s fabric. It is expressed in watts per square metre per degree kelvin, (w/m2k). The higher the u-value the higher the thermal transmittance, and therefore the lower the insulating properties of the material Reducing air pollution from your building

17 A2.5 Distribution of the heat and cooling A review of opportunities for improving the existing heating and cooling distribution and storage network should include the following areas: Ensure that all pipes, ducts and vessels are adequately insulated. This includes valves and couplings, which are often overlooked, and insulation on refrigerant pipework as poor condition will affect the temperature of the refrigerant flowing through the system and thus consume more energy in maintaining the required temperature. Ensure that all ahu filters are maintained and cleaned regularly. It may also be worth considering the use of low energy air filters, and fitting pressure gauges to indicate when replacement of filters is required. Identify opportunities for either decentralising heating/cooling and hot water provision, or combining distribution options. Large legacy calorifiers could be replaced with point of use hot water systems if hot water demand is restricted to taps. Consideration, however, needs to be given in Check that your buildings systems are appropriate for your needs Many existing buildings and their heating systems were not designed for the current building function, and so often you will find that there are a number of opportunities for reducing consumption. Many buildings have large boilers providing central heating that are oversized and not best suited for the distribution now required (in some respects this leads on to heating system replacement choice, but there may be options for simply reducing/removing elements). It is often more efficient to operate smaller boilers when the heating load is 25% to 50% of the design capacity than it is to use one large boiler to meet a partial load. Alternatively ensure that boiler sequencing controls are fitted to ensure that the load is balanced effectively between boilers, ensuring that only the minimum number of boilers is allowed to fire at any time. this instance to the change of fuel and impact that has upon costs and carbon emissions. Ensure condensing and evaporating devices are clean and well maintained. Check condensers are not obstructed, for example by equipment or vegetation. Any constant volume AHUs should be identified and considered for retrofit to a variable air volume (VAV) system. Check the configuration of each hot water valve on each heating coil (includes air handling units, fan coils, etc.). If three-way valves and constant volume pumps are installed, convert the valves to two-way and install variable frequency drives on hot water pumps. Perform combustion efficiency analysis and install automated o 2 trim systems to adjust the air-to-fuel ratio linkages feeding the boiler burner, so that they are burning most efficiently. In commercial or industrial buildings with warm air heaters and high ceilings, de-stratification fans can reduce energy use by 20% by blowing warm air down to ground level where it's needed. Consider purchasing a new energy-efficient burner if your existing burner is cycling on and off rapidly Decentralisation means changing from a centrally provided heating &/or cooling system to a local provision i.e. Smaller boilers or heaters for individual areas. Condensers are usually located on the outside of buildings and reject heat that has been removed from inside the building by the cooling system. Variable air volume (VAV) systems maintain the air flow at a constant temperature, but supplies varying quantities of conditioned air in different parts of the building according to the heating and cooling needs Reducing air pollution from your building

18 A2.6 motors, pumps, drives & fan Motors are used extensively throughout many HVAC systems. Specifying high efficiency motors when replacing can result in good savings in terms of electric power with little additional capital cost, but can also significantly improve heat distribution. Consideration should also be given to soft starts on motors if not already fitted, this generally reduces the wear and tear on the motors and reduces the need to replace. In addition, fitting Variable Speed Drives (VSDs) or purchasing motors with integral VSDs, can also reduce speeds and deliver accurate flow rates of hot/chilled water as and when required. High efficiency motors and vsds generally have one of the best paybacks within energy management, as the power to energy ratio is cubed. For example by matching air volume in ahus to actual heating/cooling loads, the use of vsds with variable air volume (vav) fans cuts energy consumption by up to 60% versus constant air volume systems. Many HVAC systems also have a variety of pumps and fans consider direct drive pumps and fans which are more efficient than those that are belt driven. Soft start: a device that can temporarily reduce the load and torque in the motor during start-up. This reduces the mechanical stress on the motor and shaft, extending the lifespan of the system. Variable Speed Drives (vsd) also commonly known as variable frequency drives or inverters are used to control the speed of AC induction motors. Energy use can be reduced considerably if the speed of the motor varies in response to the changing process conditions. Direct drive: takes the power coming from a motor without any reductions (such as a gearbox) VSDs, soft starts and high efficiency pumps reduce energy use Retrofitting vsds, soft starts and replacing with high-efficiency pumps can save up to 60% of energy consumed by fans, pumps, motors and drives where there are variable conditions of operation. The upfront capital costs also tend to be fairly low, and paybacks can be very quick. A2.7 Building Information Modelling A Building Information Model is a computer model of the physical elements of a building and how they function, and aim to help share and manage knowledge on a building through it s lifecycle, from conception to demolition. Building Information Modelling (BIM) responds to the current demands for improving building performance rapidly and cost-effectively, by going beyond the planning and design phase of a project. It extends throughout the building life cycle to include such processes as cost management, construction management, project management and facility operation. BIM presents a vast range of opportunities by providing better and more integrated tools, with more opportunity for collaborations, working through an integrated project delivery team model. BIM can quickly estimate design energy performance, enabling an understanding of how to achieve cost effective, low energy and zero carbon buildings, whilst assessing return on investments for those buildings. Specifically BIM analysis tools help analyze heating and cooling requirements, identifying major building equipment that may reduce energy use. Additionally, they incorporate local weather and electric grid data to estimate building energy consumption and carbon emissions Reducing air pollution from your building

19 A2.8 Metering, monitoring & targeting and building management Installation of MM&T can deliver 15 20% savings Ensure that all the required monitoring and metering equipment is correctly installed, and provides useful information to the facility managers and the wider organisation. Make sure the building operator understands the building. Building operators should be briefed so they understand how to operate the building to combine energy efficiency with occupant comfort. When occupants needs change (e.g. Opening on a weekend), the building operator should know how to change building controls to facilitate this in an energy efficient manner. On-going building monitoring can be used to discover faults, provide feedback and maintain low carbon performance. Monitored data should be used to optimise BMS settings. A common finding is that heating systems are coming on too early, or running for too long at the end of the day, or operating over weekends and shut down periods. Metering, Monitoring and Targeting (MM&T), is the management information system that supports energy management. It is an on-going cyclical process from data collection to taking action, via data analysis and communicating the resulting insights, as shown above. MM&T will give you: Timely, relevant information on energy use the ability to investigate the energy performance of buildings and processes The ability to take action to rectify exceptions in performance and to improve energy performance over time Energy reports to support accountability for energy use Feedback from building occupants on their perception of comfort should also be used to understand building performance. Where improvements in services and/or comfort have been undertaken, monitoring can show the impact of these improvements on the energy demand. Asset registers must also be updated and rigorous maintenance procedures and schedules created to embed the improvement of energy performance. The ability to verify savings made following project implementation. Meters and/or sub-meters should be installed for major energy consuming equipment as these enable action to identify and prevent excessive energy use. Measurements of temperature and relative humidity can assist in monitoring occupant comfort. This information also allows the efficient allocation of all budgets involved in operating the building and the ability to set energy and emissions reduction targets Reducing air pollution from your building

20 A2.9 Organisational & Behavioural change Everyone in the organisation should have some level of responsibility with respect to energy efficiency. Adapting and changing operational procedures is one way to instigate savings. In this way, energy efficient actions become an integral part of standard tasks. This may include: Including specific actions for reducing energy wastage within maintenance schedules (e.g. Changing/cleaning air filters at the correct intervals) refer also to the maintenance factsheet for other opportunities Job/priority sheets include actions for reducing energy waste (e.g. Repair of steam leaks) Ensuring that operating instructions include energy use issues (e.g. Shut down procedures). It is also worth introducing active reporting systems for energy waste (lights on, doors open, steam leaks etc.) and for staff members to make suggestions Reducing air pollution from your building

21 A3 Know your heating & cooling requirements A3.1 Introduction The most important aspect of an efficient heating system is getting the size right. It was once common practice to oversize boiler plant, to over-ensure that heating demand was met. In addition, improvements in building fabric and an increase in internal heat gains, such as from IT equipment and change of use/occupancy, means that where a boiler has not been replaced for many years, the heating load of the building may have changed significantly. It is therefore important to identify and understand core business requirements and use this to inform any proposed improvements to an HVAC system. Typical questions you should consider are: What is the current internal temperature of the building? Are employees happy with the internal environment? Are there any hot or cold spots within the building? Are there any areas of the building where temperature is critical? When is the building occupied A3.2 Calculating Heat Load/Demand There are five factors that determine the energy load of a heating system: The design, layout and operation of the building this affects how the external environment impacts on internal temperatures and humidity. The required indoor temperatures and air quality The heat generated internally by lighting, equipment and people all of these have an impact on how warm your building is; The type, design and efficiency of the heating plant; Building usage patterns. Using rules of thumb or the Simple Sizing Calculation is often sufficient to determine approximate plant requirements and sizes at the concept stage. A3.3 Rules of Thumb: Rules of Thumb are general principles derived from practice and experience rather than precise theory. They can be useful for approximately calculating values, setting outline targets and rapidly comparing different options Some example BSRIA Rules of Thumb (2011) for heating loads. Description Heating Load (w/m2 GIA) Educational Buildings 87 Industrial Buildings 80 Offices 70 Residential Buildings 60 Retail Buildings 100 Example Office Block of 1,000m 2 has 70kW heat load = 70 x Gross Internal Area (GIA): The floor area contained within the building measured to the internal face of the external walls 21 - Reducing air pollution from your building

22 No boiler is 100% efficient. Heat is lost via the flue gases and through the main body of the boiler itself. Therefore, this value needs to be adjusted to correctly size heating plant according to the plant efficiency. Boiler seasonal efficiency values should be used rather than manufacturers quoted instantaneous efficiencies, as this takes into account the actual operation of the boiler or its practical use, measured at full and part load. It is a weighted average of a defined number of hours of full and part load operation which represents a full year of operation. Note that the boiler efficiency is also affected by the heating system type. Typical Seasonal Efficiency from CIBSE Efficiency % Condensing boilers Under-floor or warm water system 90 or greater Standard size radiators, variable temperature circuit 87 (weather compensation) Standard fixed temperature emitters 85 (83 C flow 72 C return) Non-condensing boilers Modern high efficiency 82 Good modern boiler design closely matched to demand 80 Typical good existing boiler 70 Applying the Simple Sizing Calculation The following method can be used to check against existing boiler size, and/or quotations received for replacement plant. A3.4 Simple sizing Calculation This calculation method works by determining the primary heat losses in your building, and then working out the level of heating that would be required to achieve the building s desired temperature. Begin by determining the Total Heat Loss, Q T : Q T = Q F + Q V (Watts) QF is fabric heat losses; QV is ventilation & Infiltration heat losses. Watts (W) are units of power, the rate at which energy is generated or used and are often quoted in kilowatts, 1000W = 1kW. Q F = U A ΔT (W) U is the u-value for each surface material (W/m2ºC) A is the surface area of each building component (m2) ΔT is the difference between desired internal temperature and external temperature ( C) Typical existing oversized boiler (atmospheric cast-iron sectional) So for the Office Building in the previous example, assuming a condensing boiler with standard size radiators is specified, the approximate boiler size should be 70kW x (1 0.87): 80.5kW. QV = ⅓ N V ΔT N = number of air changes per hour V = volume of building (in m3) (W) 22 - Reducing air pollution from your building