Manual A - Minimising air pollution during building use

Transcription

1 Par Hill Research Reducing air pollution from your building - a series of manuals for operators, designers & developers Manual A - Minimising air pollution during building use Factsheet A4 - Select the right heating system Joanne Arbon & Iarla Kilbane-Dawe

2 Par Hill Research Minimising air pollution during building use Factsheet A4 Select the right heating system SOME CONVENTIONS USED IN THIS DOCUMENT Key information is highlighted in an orange box like this text Par Hill Research Ltd. Although every effort has been made to ensure the accuracy of the information herein, the authors and publisher can accept no liability for loss, damage or injury caused by errors or omissions in the information given in this document. The content may be distributed freely without the permission of the copyright holder in electronic or other format, so long as the source and copyright are acknowledged and no charge is made for the document. Examples and Case Studies These are shown inside a light blue box. External Resources and Clickable links to websites are shown like this are shown in blue bold typeface. ww.parhillresearch.com

3 Par Hill Research Ltd, Environment, Policy & Innovation A4 Heating System Choice & Selection A4.1 Air pollution and heating system choice Having determined your heating needs and minimised heating demand, from time to time you ll have to choose a new or supplementary heating system to meet that demand. The heating system you choose will be the main determining factor of how much toxic air pollution your building will emit (see table at right). Some systems, such as solar collectors for hot water or ground source heat pumps, both minimise air pollution and carbon emissions and are eligible for various subsidies. Others, such as biomass boilers, emit comparatively large amounts of toxic air pollution per kwh of heat generated, but are overall carbon neutral. And most types of gas boiler come in ultra low NO x variants that can minimise toxic air pollution at little or no extra cost. The impact of the pollution is also determined by the location and height of the exhaust or flue from the heating systems, and the abatement equipment interposed between the boiler and the flue. This factsheet gives details of most typical systems and explains the circumstances in which it can most appropriately be applied. Typical air pollutant emissions from different heating technologies Emissions, mg/kwh Local NO x, mg/kwh Local PM, mg/kwh CO2 emissions, g/kwh Solar thermal Heat pump (electric) Ultra low-no x gas boiler g/kWh < 40mg/kWh < 1mg/kWh 185g/kWh Oil fired boiler < 120mg/kWh 16mg/kWh 245g/kWh Proposed London CHP standard Biomass Boiler (RHI eligible) To be announced June 2013 No standard set < 530mg/kWh < 107mg/kWh 0 Pollution abatement technologies 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 type gas, oil, biomass, CHP, boiler etc there are several approaches to pollutant reduction both inside the boiler (primary or internal abatement) and by treating the boilers exhaust gases (secondary or external abatement). In addition, flue and stack heights can be increased so as to reduce or eliminate the likelihood of flue gases reaching the ground or surrounding buildings Reducing air pollution from your building

4 Par Hill Research Ltd, Science, Environment & Policy Research Choosing your heating technology Are you in an AQMA? Yes Read A4.1 and avoid CHP & Biomass if possible. No Do you have continuous high heat and electricity demand, 24/7? Yes Are there access, fuel storage or planning restrictions? No Read A4.2 Consider CHP No Yes Do you have continuous low heat demand, 24/7? Yes Read A4.3 consider installing Heat Pumps No Do you have high hot water demand? Yes Read A4.4 consider installing Solar Hot Water No Does the site have restricted access or limited fuel storage? Yes Read A4.5 consider installing Ultra low-no x gas boilers No Read A4.6 consider installing Biomass Burners 25 - Reducing air pollution from your building

5 Par Hill Research Ltd, Environment, Policy & Innovation Primary abatement methods For each boiler technology there are often several ways to reduce emissions to the exhaust. Approaches based on loading and efficiency typically require that the burner or boiler is mainly operated at the loading at which it is most efficient depending on the technology this can vary between 50% and 90% of maximum load, or can require the system to operate continuously. You must therefore scale the boiler chosen so that the typical demand is met at the optimum efficiency level. For example, meeting 100kW demand for heat from a gas boiler that is most efficient at 90% load means that the boiler should ideally have maximum output of 110kW, while meeting it using an Internal Combustion CHP system that s most efficient at 50% load requires a 200kW rated system. In gas boilers and CHP systems, combustion temperature approaches, often involving lean burn, water injection, exhaust gas recirculation or low-no x boiler designs that reduce the flame temperature, aim to reduce NO x pollution by ensuring the fuel is burned completely or reducing the amount of nitrogen from the air that is burnt in the combustion process. Ultra low-no x designs exist that reduce NO x emissions to below BS Class 5 levels (see right). Biomass boiler abatement tends to focus on minimising PM emissions as these are much greater from biomass fuel than from fossil fuel. These approaches tend to focus on the quality of the fuel used in particular ensuring that it stays dry, as well as controlling the supply of air to the burner. Again, the design of the overall system and correctly matching heat demand to heat supply is important biomass burners tend to be most polluting during startup so heating systems should be designed to ensure continuous operation where possible. Secondary abatement methods Again, the choices of secondary abatement depend entirely on the choice of fuel and burner technology to be applied. For biomass boilers abatement is 26 - Reducing air pollution from your building Boiler NOx emissions classifications Under standard CEN 483/BS EN 297:1994. Also is the CSH/BREEAM ultra low-nox standard. Boiler Class Maximum Emissions, mg/kwh NOx Also shown are the CSH & BREEAM points awarded for Class 4 and 5 boilers and the requirement to achieve the maximum points under 1 category Pol CSH/BREEAM Ultra-Low NO x 40 mainly mechanical or electrostatic, using filtration or centrifugal methods to remove particles from the air. For CHP and gas burners a variety of exhaust treatments are available, confusingly known by the similar acronyms SNCR, SCR and NSCR. Selective Non-Catalytic Reduction (SNCR) requires very high temperature (1,100 C) injection of ammonia or urea into the burner this chemically converts nitrogen oxide to nitrogen gas. This approach is popular in the UK, not least as it s considerably less expensive than SCR and NSCR. Selective Catalytic Reduction (SCR) also requires ammonia or urea, but operates at a much lower 400 C or so, but the catalysts are often expensive and can as much as double the price of the boiler system. Non-Selective Catalytic Reduction (NSCR) uses a fuel and a catalyst to convert the NO x into nitrogen gas. In all three cases, reductions of 75%-90% in the exhaust emissions of NO x are typically achieved. The US EPA provides comprehensive information on abatement technologies: EPUK Guidance exists, but cannot currently be downloaded.

6 Par Hill Research Ltd, Science, Environment & Policy Research A4.2 Systems suitable for High, Steady Heat Load; Not In An Area Restricted By Air Quality Issues, Site Or Planning Restrictions: CHP & Tri-generation CHP technologies are mature and proven - there are over 1,500 CHP schemes in operation in the UK. CHP is widely supported by the Government as it results in high efficiency of fuel conversion - if well located, sized and designed, it is thought that they can achieve overall efficiencies in excess of 70% at the point of use. This compares to a typical figure of 40% for electricity provided via the grid from conventional power stations. However, the local levels of emissions are much higher and therefore CHP should be avoided if in an air quality restricted area. There are a growing number of CHP installations now that are utilising hydrogen and fuel cell technology, which addresses a number of these environmental concerns. Combined heat and power (CHP) also known as co-generation, refers to the simultaneous generation of usable heat and electricity. Tri-generation Heat from a CHP plant can also be used to generate cooling by using an absorption chiller unit. CHP that produces heat, electricity and cooling is termed tri-generation. Additional practical considerations are that: The exhaust gases from a CHP plant can cause nuisance within the local environment if incorrectly designed and operated. Adequate pollutant dispersion can be achieved by ensuring that flues are sufficiently high. CHP installations in London should meet London s CHP NO x and PM emissions standards from mid-2013 onwards. Good Quality CHP does not refer to air pollution emissions The DECC definition of Good Quality CHP (see later) does not reflect it s air pollution impacts and in some cases can incentivise systems that emit high levels of toxi NO x and PM 10 air pollution. Correct sizing of a CHP unit, based on accurate estimates of likely heat and electricity loads, is essential and needs an in-depth feasibility study Planning permission may be required for flues, even for packaged CHP installed within existing buildings. There can be substantial upfront costs, particularly for infrastructure, requiring long-term investment with long payback periods. For industrial district heating or CHP, customers can be locked into a monopoly single long-term supply contract for electricity and heat. Maintenance: micro, mini and packaged CHP units can be left to run without much need for user interaction. Routine maintenance is required at least every 1,000 hours of operation. Industrial and district heating CHP require operational staff and annual routine maintenance of the plant. Costs and payback vary significantly, with major influences including the site requirements, technology, fuel and level of demand for the heat produced. Ballpark figures are from 750 per kwe for large scales schemes and up to 11,000 per kwe for small systems. The smallest household systems use Stirling Engines, larger systems use Internal Combustion Engines or small turbines, the largest use giant ICE or gas turbines as found in power stations. Some CHP technologies are noisy, especially internal combustion engines. Large scale CHP can have landscape and visual impacts given that plants are large structures Reducing air pollution from your building

7 Par Hill Research Ltd, Environment, Policy & Innovation Case Study: Palestra Building TfL has installed a 2.4m Combined Heat and Power (CHP) plant, including the hydrogen fuel cell, at the Palestra building to generate energy locally, cut carbon emissions and save money off energy bills. It is estimated that the fuel cell and power plant will cut carbon emissions by up to 40 per cent and generate 90,000 cost savings per annum. The state of the art hydrogen fuel cell, will provide electricity, heat and cooling to the building. In addition, the building's hot water supply will be heated by the fuel cell. At times of peak energy use, the building will generate a quarter of its own power, rising to 100 per cent off-peak. The waste heat from power generation will be pumped into a unit on the roof which will work to keep the building cool and supplements the building's six electric chillers. kwe: CHP units are sized according to their electrical power capacity, hence the small e. Therefore a 300kWe unit will have the capacity to generate up to 300kW of electricity. Typically a 300kWe CHP unit would generate up to 430kW of heat. eligibility for ROCs for the biomass element of fuel used in biomass or energy from waste CHP plants reduced VAT on the installation of micro-chp eligibility for the Renewable Heat Incentive, where a qualifying renewable fuel source is used (NB: CHP installations will not need to meet the CHPQA standard in order to claim the RHI) eligibility for the Feed in Tariff for electricity generated up to 5MW installation size. Scale of the building Single units Some typical costs and paybacks for CHP installations CHP Technology Stirling engine system Costs of the installation up to 11,000 per kwe Simple Payback, years Lifetime cost of carbon saved per tonne of CO to 60 Funding CHP schemes There are no direct funding or grants available for CHP, but many Government funded incentives to help recoup the capital and running costs if you have Good Quality CHP registered with the CHPQA. These include: exemption from the Climate Change Levy for all Good Quality CHP fuel. eligibility for Enhanced Capital Allowances (ECAs) for Good Quality CHP plant and machinery Building level District level ICE or microturbine Large ICE or turbine & DH network 750 per kwe/ 1000 per kwe 750 per kwe/ 700 to 1,000 per meter to 250 over to 250 Source: LGA business rates exemptions for certain Good Quality CHP schemes enhanced eligibility for ROCs for renewable CHP schemes The LGA s CHP Checklist is a useful resource on these issues: Reducing air pollution from your building

8 Par Hill Research Ltd, Science, Environment & Policy Research When to install CHP The best time to consider installing CHP is at the design stage for a new installation or building, as it can be fully integrated into the design specification. However, it can also be successfully retrofitted into existing sites. CHP makes sense on sites with a heat demand of over 4,500 hours a year, and a 24/7 requirement for electricity. This equates to an average heat demand of about 17 hours a day for five days a week, throughout the year. In general, the greater the demand, the higher the monetary and carbon savings. If correctly sized to meet demand, there can be a short payback on investment of around three to five years. It is worth bearing in mind that modern high efficiency/condensing boilers are more efficient than the micro-chp units currently available (although they do not have the advantage of electricity production), therefore, you will not see significant energy bill savings if replacing a recently installed boiler. CHP also makes sense for sites requiring security of supply as the owners of CHP installations have more, independent control over their electricity and heat supply The Renewable Heat Incentive (RHI) is a UK Government scheme set up to encourage uptake of renewable heat technologies through the provision of financial incentives that are tariff based payments per unit heat generated. Feed-in-Tariffs (FITs) are financial incentives for the generation of renewable electricity, similar to the RHI. Renewables Obligation Certificates (ROCs) are green certificates issued by Ofgem to operators of accredited renewable generating stations for the eligible renewable electricity they generate. CHP Focus is DECC website to support the development of CHP in the UK. It includes comprehensive information on all aspects of CHP. It also includes a useful self-assessment tool for sizing CHP. See: chp.decc.gov.uk Enhanced Capital Allowances (ECAs) are an accelerated tax relief. The ECA scheme for energy-saving technologies encourages businesses to invest in energy saving plant or machinery specified on the Energy Technology List (ETL) which is managed by the Carbon Trust on behalf of Government. The ECA scheme provides businesses with 100% first year tax relief on their qualifying capital expenditure. The ETL specifies the energy-saving technologies that are included in the ECA scheme. The scheme allows businesses to write off the whole cost of the equipment against taxable profits in the year of purchase. Additional Guides, Case Studies & Tools are available from the CHP Association and the Carbon Trust & CHP Quality Assurance (CHPQA) allows owners with CHP that meet the Good Quality CHP criteria to apply for certification and hence qualify for benefits: chpqa.decc.gov.uk 29 - Reducing air pollution from your building

9 Par Hill Research Ltd, Environment, Policy & Innovation District Heating District Heating (DH) systems provide multiple buildings or dwellings with heat and hot water from a central boiler house, or energy centre. The system can provide heating or cooling which is transferred from the energy centre through a network of highly insulated pipes carrying the water to each building. Every building has a heat exchange unit including a heat meter to monitor how much heat is used. Depending on the size and density of the network, there are a number of different energy sources that can be used for district heating, including biomass, geothermal heat, energy from waste, solar systems, heat pumps, waste heat from industrial processes, in addition to conventional boilers and cogeneration. This technology is much better suited to urban areas than sub-urban or rural environments, where heat densities are higher. The boiler or CHP engine must be located closer to populations, therefore, local emissions are of particular concern (nitrogen dioxide (NO 2 ) and particulates (PM 10 and PM 2.5 )). Exhaust gas treatment technologies are used to reduce the level of pollutants produced and are required. The LDA s District Heating Checklist is a useful resource on these issues: Many district heating schemes are financed through the development of an Energy Service Company (ESCo) or the use of an Energy Performance Contract. An ESCO is a business that develops, installs, and arranges financing for projects that improve the energy efficiency and maintenance costs for facilities over a long time period. ESCOs generally act as project developers for a wide range of tasks and assume the technical and performance risk associated with the project. They usually include in the cost: development, design and financing for energy efficiency projects; install and maintain the energy efficient equipment involved; measure, monitor, and verify the project's energy savings; and assume the risk that the project will not save the energy expected. Similar to CHP local carbon emissions will also be high, unless it is making use of waste heat from industrial processes. It could be said that this is free heat since it would otherwise be dissipated to the air or water. Infrastructure provision is the major limiting factor due to levels of disruption and high upfront capital investment. That said, if installed well, the system will last for many decades which means that fuel sources can be changed from fossil fuels to renewable as the economic viability of the latter improves. Costs for a district heating scheme vary considerably. District heating networks are long-term projects with long-term paybacks. They are unlikely to be suited to short-term investors. The biggest cost of district heating is the investment required to establish the pipe network Reducing air pollution from your building

10 Par Hill Research Ltd, Science, Environment & Policy Research There are similar funding opportunities for District Heating as for CHP. District heating is also eligible for the RHI, where the heat is produced by an RHIeligible installation. There is no specific uplift for district heating installations, even though the cost of district heating (or other off-site use of heat) will often be higher than the cost of using the heat from a similarly sized installation onsite (due to the costs of pipe-work to transport the heat, and other cost factors). District Heating scheme success depends on growth of the scheme The success of district heating is reliant on a consistent and/or growing consumer base. Consumers may not want to find themselves tied into a heating system that they are unhappy with. An indicative cost guide for commercial systems: infrastructure per square metre costs 8.40 in a city centre and in an urban area. The cost of a heat exchanger and meters (per kw) is 20 for both city centre and urban area commercial systems. Source: Heat Pump Association A4.4: For Low, But Steady Heat Load Requirement In An Area Restricted By Air Quality, Use Heat Pumps Ground-source heat pumps (GSHPs) and Air-source heat pumps (ASHPs) utilise naturally-occurring underground low-level heat, or low-level atmospheric heat, and convert it into usable high-grade heat. Water Source Heat Pumps are also available but require a water source. GSHPs are better suited to new builds with appropriate geological features, whilst ASHPs can be attached to the outside of existing buildings. Ground- and Air- source heat pumps are not completely renewable as they require electricity to drive their pumps or compressors. The advantages of using heat pumps: They are a versatile heat generation resource that can be used at different scales and applications. In some situations they can also be reversed to provide cooling If driven by renewable energy sources, they have no direct CO2 emissions associated with heating. They can be retrofitted to existing heating systems. The heat generated receives generous subsidies from the Feed-in Tariffs. They are very low maintenance. They produce no local pollution, and there are no flue or ventilation requirements 31 - Reducing air pollution from your building

11 Par Hill Research Ltd, Environment, Policy & Innovation A heat pump with mid-range efficiency can be expected to use only a third of the energy of an average existing gas boiler to produce the same amount of heat bear in mind that gas is a cheaper fuel however than electricity (and lower carbon intensity) therefore the level of savings achieved are greater where natural gas is not available. A lot of ground work and civil engineering is required for GSHPs both borehole and slinks (horizontal) systems, and so can cause high levels of disruption and additional cost. Installation of an ASHP involves siting an external unit and drilling holes through the building wall. This may require planning permission.heat pumps have very few moving parts and so require minimal maintenance. The inverter will probably require replacement over a heat pump life span (20-25 years). For a commercial system the inverter is likely to constitute 10 to 20 per cent of project costs. Costs vary according to the technology used and the scale of the installation - as a very general guide, the installed cost of a typical system would be about 1,200 per kwth capacity (Carbon Trust). This estimate does not include the cost of the heat distribution system. A heat pump for a small office would cost between 5,000 and 12,000 (for 5-12kWth system). Ground and Water Source Heat Pumps are eligible for RHI payments this is to be extended to include Air Source Heat Pumps from All ground and water source heat pumps of 45kWth capacity or less, will need to be certified under the Microgeneration Certification Scheme (MCS) or equivalent schemes to be eligible. The Microgeneration Certification Scheme (MCS) is a mark of quality and demonstrates compliance to industry standards that companies strive to meet. It highlights to consumers that companies are able to consistently install or manufacture to the highest quality every time. When Heat Pumps Are Most Suitable Heat pumps are best suited to low temperature heat distribution systems, such as under floor heating. This is largely due to traditional radiator systems demanding higher operational temperatures of up to 80 C. The success of using heat pumps depends greatly upon the co-efficient of performance (CoP) of the system which effectively tells you how much bang you get for your buck in relation to how much heat you get per kwh of electricity used (i.e. a CoP of 4 means that you get 4kWh of heat for every 1kWh of electricity generated). The CoP itself is dependent upon the temperature differential between the heat source and the internal heat demand - to maximise efficiencies it is important to have a low heating distribution temperature but also as high a source temperature as possible. In the UK GSHPs temperatures beneath the surface remain fairly constant (8 to 12 C) even throughout the winter. This stability means that the heat output of the pump is fairly stable throughout the year. It is important that for GSHPs the systems are sized correctly and enough land space allowed to ensure that the site does not overcool as it can become susceptible to permafrost. If sufficient efficiencies are not reached, the CO2 emissions from the heat may be greater than traditional technologies (assuming mains electricity used). System sizing is very important. Oversizing a system leads to heat dumping (in the surrounding area if no thermal store is available). An undersized unit would require backup using non-renewable fuels. Heat Pump Association s website contain further information: The Carbon Trust also have some good guides on how to implement heat pumps Reducing air pollution from your building

12 Par Hill Research Ltd, Science, Environment & Policy Research The Economics of Solar Hot Water Solar hot water heating is only truly economically viable in a business where there is a sufficiently high level of demand for hot water, such as in a canteen. Generally, solar hot water is more economical in larger systems. Ideally, systems should be roof-mounted. The optimum orientation is due south, though a collector will work almost as efficiently between SW & SE. If considering an installation on an E/W roof, the collector area should be increased by up to 25% to accommodate losses in efficiency. On a UK roof, the ideal pitch of the collector is around 35 from the horizontal It is also advantageous to be able to locate equipment (such as the heat exchangers) in the roof space close to the collectors. Average daily solar heating in the London Region (Carbon Trust) A4.5 For High Hot Water Demand use Solar Hot Water systems Solar thermal or solar hot water systems work by absorbing energy from the sun and transferring it, using heat exchangers, to heat water. There is a common misconception that solar thermal systems do not operate when it is cloudy. When the sun s radiation passes through clouds, it is dispersed and is known as diffused radiation. On clear days, with no dispersion effect, it is known as direct radiation. Solar thermal systems work in both conditions. The average daily values for both diffused and direct irradiation for the London area are shown above, from a Carbon Trust study. This also shows that solar thermal systems will provide more hot water during the summer than during the winter. This means that an auxiliary heat source may still be required to heat the water during the winter months. However, solar thermal systems are still able to save between 40% and 60% of the energy that would have been required annually to heat up the hot water using conventional energy sources, such as gas. Flat plate collectors are generally cheaper than evacuated tube collectors with a good cost-performance ratio. Evacuated tubes are highly efficient even with low solar radiation, as well as in circumstances where there is a large temperature difference between the absorber and ambient temperatures. In general, evacuated tubes are more expensive and cannot be installed integral to the roof. Retrofitting is a more costly option due to the complex nature of installation. However, a solar thermal system can be integrated into an existing gas-boiler system. Although planning permission is not usually required for small-scale solar water heating systems, you should contact your local authority for advice on planning restrictions. A system for a small office would use about 4m 2 of roof space and cost about 5,000, and would contribute around 2,000kWh. Maintenance costs for solar water heating systems are generally very low. Most solar water heating 33 - Reducing air pollution from your building

13 Par Hill Research Ltd, Environment, Policy & Innovation systems come with a five-year or ten-year warranty and require little maintenance. A number of types of solar thermal collector are eligible for funding under the Enhanced Capital Allowance (ECA) scheme. RHI tariffs are also available for solar thermal isntallations (up to 200kWth) however, all solar thermal plants of 45kWth capacity or less need to be certified under the Microgeneration Certification Scheme or equivalent schemes A4.6 No Steady Or Significant Heat Load Requirements, Located In An Air Quality Restricted Area, And/Or Have Site Restrictions use boilers The key advantages of using boilers as your heat generators are: Large capacity range available Good seasonal efficiencies (especially condensing type, ~92%) Flexible fuel choice Modular systems provide flexibility to match loads The Carbon Trust supplies guidance and tools for feasibility and sizing assessments, and templates for setting up contracts: Low temperature hot water (LTHW) boilers produce hot water at around 90ºC and are the type most commonly found in commercial premises. The hot water produced is distributed via pipework to wet heating systems and hot water storage tanks. Steam and high temperature hot water (HTHW) boilers are more commonly used in industrial sectors. They are found in circumstances where there is a continual demand for steam or hot water. Other large users of these utilities are laundries and hospitals. If your boiler is more than 15 years old, it is likely to be a conventional type of standard boiler, designed to operate with an average water temperature of 60 to 70 C. They tend to be larger than boilers of more modern design. Businesses using such boilers should consider replacing them with models that comply with current regulations. Check the boiler plate to find some key information The Solar Trade Association has more information: You can find out things like your boiler s rating, age and settings from the manufacturer s plate. This is usually found on the side of the boiler casing. Older boilers may not have this plate, and this can give away a boiler s age Reducing air pollution from your building

14 Par Hill Research Ltd, Science, Environment & Policy Research Legal requirements on boiler efficiency Since the end of 1997, legislation has imposed minimum efficiency requirements for boilers with outputs of up to 400kW. Current UK boiler efficiency regulations recognise three types of boiler standard, low temperature and condensing. [NB: The UK Building Regulations & EPBD recognise only two types standard and condensing]. Boiler sizing Sizing of the boiler is particularly important as they operate most efficiently at full load. They are not well suited to low temperature applications, such as, under floor heating, where a condensing boiler is a better option. Don t forget that even if a condensing boiler is not appropriate, or technically feasible, there is still potential to extract heat from exhaust gases through the use of a heat exchanger. The heat can be used to pre-heat the return water or the combustion air. Increasing the temperature of the combustion air by 20ºC can improve the overall efficiency of the boiler by 1%. Condensing boilers are most efficient at part-load not full-load Condensing boilers operate more efficiently (i.e in condensing mode) at part load conditions, so this should be taken into account when sizing. There are also limitations in siting of condensing boilers, as they require a condensate drain, and so must have external access. Condensing boilers also generate lower temperature flue gases and as a result you get visible plumes of steam. This may cause problems if the flue outlet is close to other building surfaces/openings. High-efficiency boilers: Boilers that meet the minimum efficiency requirements of the current regulations are generally marketed as high-efficiency boilers. So if you have a standard boiler which was installed from 1997 onwards, it is likely to be this type. These boilers have; a lower water content, larger heat exchanger surface areas and greater insulation of the boiler shell compared to conventional designs. High-efficiency boilers can work with all types of heating system. They are particularly suited to applications where a higher water temperature is required, such as space heating systems using radiators designed to operate at typical flow temperatures of 80 C or some process heating applications. Condensing Boilers: Condensing boilers have an extra heat exchanger surface to extract much of the waste heat in the exhaust gases and return it to the system. Condensing boilers are the most efficient on the market and since April 2005, regulations require that they must be considered as the first choice for all new or replacement space heating installations. However they may not be the appropriate choice for businesses with applications with continuous full load demands for water at higher temperature (up to 90 C) as the return temperatures will never be low enough to put the boiler in condensing mode, and so overall efficiency is lower. Combination boilers Combination (or combi ) boiler, contain a secondary heat exchanger within the boiler housing that is used to provide hot water instantaneously. There is no need for a hot water storage cylinder and associated cold water feed tank and pipework. They can be particularly attractive options in properties where space is limited or if your business is run from a small building and hot water demand is limited to taps Reducing air pollution from your building

15 Par Hill Research Ltd, Environment, Policy & Innovation When are modular boilers suitable? Modular boiler systems are best suited to buildings or processes with a significant, variable heat demand Modular boiler systems A modular boiler system uses a series of boilers linked together to meet a variety of heating demands. Most boilers give optimum efficiency at a particular load point (standard boilers at full load, condensing boilers at part load) so, it makes sense to have a series of boilers operating at around their peak efficiency loads and together matching the range of heating demands that may be experienced in your building. Modular systems are generally composed of several identical boiler units although a mix of condensing and conventional boilers could be used. The condensing boilers should in general be the lead to maximise system efficiency. To gain the maximum benefit from arrangements of this type appropriate sequence control needs to be implemented Refer to Factsheet A7- Best Practice for controls Example application of a modular boiler system Consider a building with a peak winter heating demand of 100kW. If a single standard boiler were to be used, it would operate at full capacity, and peak efficiency, for only a few weeks of the year. If three modular boilers of 35kW each were used instead, lower heating demands experienced at other times of the year could be met by a reduced number of boilers operating at full capacity. Low & Ultra Low-NO x boilers As referred to in A4.1, low and ultra-low NO x variants of all boiler types exist, in which primary NO x abatement methods have been used to reduce NO x exhaust emissions to Class 5 or better. In many cases these variants are the same cost as higher NO x emitting systems and often are more efficient too. Wherever possible, installation of low or ultra-low NO x boilers should be the preferred option, as they reduce pollution for little or no cost. Costs Condensing boilers were traditionally more expensive than high-efficiency standard boilers, however they are now fairly competitive. They are also more efficient and cost less to run. So any extra cost is quickly paid back. Generally costs vary widely for boilers. However, SPONS M&E (2011) provides industry average prices for mechanical and electrical services, giving a reasonable and accurate indication of their likely cost. It includes a section on heating systems, and provides the following: Gas Fired conventional/standard: o kW circa 4,000 o kW circa 10,000 Low NO x Condensing, floor standing: o 100kW 4,300 o 300kW 11,200 Steam & High Temperature Boilers: As this guidance is aimed at the SMEs, we have not covered these boilers in great detail. However, the Carbon Trust have produced a very informative guide on this range of boilers, and their specifications. We would direct users to this if required Reducing air pollution from your building For more info see Carbon Trust Guide CTV052L on Steam & High Temperature Hot Water Boilers.

16 Par Hill Research Ltd, Science, Environment & Policy Research A4.7 No Steady Or Significant Heat Load Requirements, Not In An Air Quality Management Area, And Areas Having No Site Restrictions: Biomass boilers are suitable Biomass energy generates power, heat or both by burning organic material. Biomass is a versatile renewable heat and power generation resource that can be used at different scales and applications, but while almost CO2 neutral, tends to be high or very high in PM and NO x emissions, making it unsuitable for many applications in locations with air quality problems. It is essential to ensure that any system will comply with legislation such as the Clean Air Act (1993) and local air quality management plans, although there are few restrictions for biomass at the building scale if the fuel is clean wood chip. Since April 2008, the flues of wood burning appliances have been classed as permitted development except in conservation areas, World Heritage Sites and in listed buildings. However, the council should be consulted if the flue is likely to extend 1m or more above the height of your roof, or is to be installed on the principal elevation visible from a road. Construction of a separate boiler house and fuel store is likely to require planning permission. There may also be restrictions on the installation of biomass boilers in old or unusual buildings (for example, listed buildings). In such cases consultation with the local planning authority is necessary. Because most biomass is cheaper than fossil fuels it provides good value space and water heating with relatively short financial payback periods. And in some cases it can directly replace existing fuels without changing technology/heating plant. The Biomass Energy Centre keeps a list of suppliers of biomass fuel. Biomass fuel needs transporting, know how much you ll need It is important to have an understanding of the amount of fuel you will require. The Forestry Commission provide the following simple calculation, based on heat load kwh requirements: Multiply yearly kwh usage x to give Gj value. GJ 19 = Tonnes of oven dried wood (x ODT18 m³ Pellets19 = ODT 0.9 x 1.5 m³ Virgin chip20 = ODT 0.65 x 3 m³ Recycled chip21 = ODT 0.8 x 5 Worked Example of 100kW boiler using 100,000kWh/year would require annually; 30m³ Pellets/yr 83m³ Virgin chip/yr 112m³ Reprocessed chip/yr The upfront cost of a biomass heating system, however, is more expensive than an equivalent capacity fossil fuel fired system; thus determining the optimum sized boiler to match a site s requirements is of great importance. Biomass boilers are more than twice as expensive to buy as conventional boilers. Typical installation costs for a medium size office/school is circa 40,000. In general installed cost per kw decreases with increasing scale. The introduction of the RHI does generate offset income, which should be taken into consideration when investigating opportunities Reducing air pollution from your building

17 Par Hill Research Ltd, Environment, Policy & Innovation Funding biomass installations: In addition to the availability of RHI tariffs, there is a good level of financial support for investing in biomass. Forestry Micro-Enterprise Grant: Wood Energy Business Scheme Grants of between 2,500 and 25,000 will be available towards buying new machinery or equipment, building handling or storage facilities or installing woodfuel systems. It is funded by the Rural Development Programme for England and is administered jointly by the Forestry Commission and the East Midlands Development Agency. Wood Energy Business Scheme - A Forestry Commission Wales initiative which aims to establish a network of wood-fuelled installations across Wales and strengthening the timber supply chain. Available until Woodfuel East Boiler Installation Grant Scheme - Funding of up to 40 per cent for installations of modern, automated, woodchip-fired combustion systems. Available to farms, small energy supply companies, micro-enterprise projects, tourism projects and community buildings. Rural Development Programme The RDP is a significant sum of European funding for the development of rural areas. Funding is available for a wide range of activities including the development and diversification of land based businesses and the installation of biomass boilers. Schemes are administered differently in different areas of the UK. Biomass systems require a lot of management and maintenance The upfront cost of a biomass heating system, however, is more expensive than an equivalent capacity fossil fuel fired system. Due to the physical properties of the fuel, the system footprint is also larger for biomass plant than an equivalent capacity fossil fuel fired system; space is also required for fuel delivery, storage and transfer. A 500kW wood pellet boiler unit has a footprint of 15m2. Biomass boilers require more management and maintenance than many other technologies. This includes: regular ash removal this might be weekly for large boilers and monthly for room heaters annual cleaning of the burner this can be done as part of a maintenance contract with a fuel supplier or boiler manufacturer filling stoves with fuel log burning stoves and boilers have to be filled with wood by hand: some pellet and chip burners use automatic fuel feeders which refill them at regular intervals from fuel storage units called hoppers Case Study: Stansted Airport The 2000kW biomass heating boiler is one of the biggest in commercial use in the UK. It is powered by woodchips. Results indicate the biomass technology is set to help reduce predicted annual gas consumption at the airport by nearly 40% Reducing air pollution from your building