NHBC guide to renewable energy - NHBC Home

NHBC guide to renewable energy

May 2007

Page 2 of 19NHBC Technical

Index

NHBC guide to renewable energy May 2007

Page

1. Introduction 3

2. Solar thermal (solar water heating) 4

3. Solar electric (photovoltaic) 6

4. Heat pumps (ground source and air source) 8

5. Wind turbines (small scale, building mounted) 11

6. Biomass (domestic biomass heating systems) 13

Appendix A – Annual total UK solar irradiation map 15

Appendix B – Typical system costs 16

Appendix C – UK Microgeneration Certification Scheme 16

Appendix D – Relevant standards and additional information 17

Appendix E - Acknowledgements 18

INDEX


Introduction

NHBC guide to renewable energy May 2007

The UK government is calling forcarbon dioxide emissions to be cut inorder to address climate change andhas identified housing as a sector thatcan make a significant contribution.The consultation document ’Building AGreener Future: Towards Zero CarbonDevelopment’1 suggests challengingenergy efficiency targets for new buildhomes, which will require the use ofrenewable energy technologies.

Already, planning authorities areimplementing the ’Merton Rule‘,requiring some of the energy demandin new developments to be met byrenewable energy and theimplementation of the Code forSustainable Homes2 will give further encouragement.

This guide, prepared with assistancefrom BRE, provides guidance to NHBC

registered builders specifying orinstalling renewable energy technology.It covers the most commonly used‘microgeneration’ technologies:

� Solar thermal (solar water heating systems)

� Solar electric (photovoltaic)

� Heat pumps (ground source and air source)

� Wind turbines (small scale, building mounted)

� Biomass (domestic biomass)heating systems.

It brings together useful informationfrom a variety of sources, and presentsit in a single, concise publication thatwill help readers identify those aspectsof specification and installation

necessary for systems to work well anddeliver environmental benefit, withoutgiving rise to unexpected problems.

Renewable energy is an emerging fieldin the UK and there are currently fewsystems that have been independentlyassessed and certificated. BRE isworking with the Department of Tradeand Industry to develop the’Microgeneration Certification Scheme‘.Further information is available atAppendix C, and up-to-date informationcan be obtained from the Scheme’swebsite: www.ukmicrogeneration.org.

This guidance does not form part of the NHBC Standards.

1 & 2 Communities and Local Government,December 2006

Solar thermal

Heat Pump

Wood store for biomass heating system

Building mounted wind turbine

Biomass heating system

Garden contains buried coils for heat pump system

N

W E

S

Solar electric (PV panels)

Garage

1.1 Domestic scale renewable energy technologies

INTRODUCTION

http://www.redbooklive.com/page.jsp?id=135

The technologySolar thermal systems harness energyfrom the sun to heat domestic hot water.

Various systems are available, butgenerally a solar thermal collector,installed at roof level, absorbs the sun’senergy and transfers it into a liquid(normally a water/antifreeze solution).This liquid is circulated through a heatexchange coil in the hot water cylinderwhere its heat is transferred to thecooler water in the lower part.

Most UK systems have a ‘back-up’system (normally the central heatingboiler) which heats the water further toreach the desired temperature asnecessary, depending on theavailability of sunshine and thedemand for hot water. The systemoperation is controlled by an automaticelectronic unit, which compares thetemperatures of the collector andcylinder or store.

Many systems use a ’flat plate‘collector - a specially coated metal

sheet incorporating fluid channelsinside a weatherproof insulatedenclosure with a glazed cover. Thethermal tile is an ultra-low-profile,modular variation of the flat plate.There is also an evacuated tube typecollector which has an array of narrowstrip collectors fitted inside glassvacuum tubes, which minimise heatloss. These are more efficient atabsorbing the sun’s energy but tend tobe more expensive.

Systems can be designed to blend inwith the building - for example, roof-integrated collector panels have a lowprofile design and can be less

conspicuous. Alternatively panels can be mounted out-of-sight on outbuildings.

Some installations feature separatesolar pre-heating and back-up cylindersbut the most common configuration isto use a single twin coil cylinder wherethe lower coil connects to the solarsystem and the upper coil connects tothe back-up system or boiler.Alternatively some systems use athermal store, the content of which isheated by the collector; cold waterthen passes through a coil located inthe store and is heated instantaneouslyas required.


Solar thermal (solar water heating)

SOLAR THERMALNHBC guide to renewable energy May 2007

Flat Plate Collector

Black heatabsorbing surface

Reflectivematerial

Hot water out

Cold water in

Insulation

Box

Glazing

2.2 Flat plate and evacuated tube solar collectors

Evacuated Tube Collector

Connecting screw

Glass tube

Metal fin

Metal tube

Heat exchanger which sits in the manifold

2.1 Flat plate and evacuated tube solar collectors

Solar thermal systems can be used toprovide pre-heated water to solarcompatible combination boilers. Waterpreheated by the system is stored in asmall cylinder and feeds the boiler toreduce the energy needed from gas oroil. The boiler manufacturer should beasked to confirm suitability.

Solar thermal systems reduce theconsumption of fossil fuel for domesticwater heating, and systems cantypically provide between 55 and 70%of the hot water requirement. A solarcollector area of 3-4m2 is normallyrequired for a three-bedroom house.

Design considerationsThe solar energy resource variesacross the UK (see ‘Annual total solarirradiation’ map at Appendix A). Thefurther north, the less solar energythere is and the greater is the collectorarea required to capture it.

Collectors should be sited onunobstructed roofs, ideally facingsouth, southeast or southwest. It is notadvisable to install them on north-facing roofs. Shadows from adjacentbuildings, trees and chimneys, etc. willreduce the amount of energy collected.Collectors should be located so thatthey can be safely accessed forcleaning and maintenance, although ata pitch of more than 15° they arenormally self-cleaning.

The roof structure will need to bedesigned to accommodate the load of

the collectors – it may be necessary toseek the advice of a structural engineeror the designer of the roof-structure.

Additional space will need to beavailable inside the building toaccommodate the larger cylinders orthermal stores necessary and the floorconstruction will need to be capable ofwithstanding their load.

The system control panel and displayshould preferably be located in aprominent position, such as in thekitchen or alongside the centralheating programmer. An electricalfused spur outlet will normally berequired. Pumps and controls shouldbe located so that they are accessiblefor maintenance.

Planning permission may be requiredfor solar collectors.

Installation tips� Ensure solar collectors are securely

fixed to withstand wind loads, etc.

� Weatherproof all penetrationsthrough the roof covering withsuitable flashings, purpose-madetiles, etc. Sealant is not suitable forthis purpose and will not besufficiently durable.

� Install pipes to falls and provideinsulation to them as required by the design.

� Fix permanent labels and flowarrows to pipework, valves, etc.

� Ensure that the system iscommissioned properly and test forcorrect operation.

� Provide operating instructions andmaintenance recommendations for the homeowner.

Health and safetyCare should be taken to address allissues, including:

� the potential for excessivetemperature and pressure in heattransfer fluids and stored water

� the risk of Legionnaires’ disease -this is a potentially fatal form ofpneumonia that can thrive inpurpose built water systems unlessthey are properly managed. Furtherguidance can be found atwww.hse.gov.uk/legionnaires/index.htm and in the HSE’s ApprovedCode of Practice & Guidancedocument, L8

� working at height

� electrical safety.

Additional informationSee Appendix C for information on theDepartment of Trade and Industry’s’Microgeneration Certification Scheme’.

See Appendix D for relevant standardsand additional information.


Solar thermal (solar water heating)

SOLAR THERMALNHBC guide to renewable energy May 2007

2.3 Three types of solar water heating system

Pumped

Solar collector

VentRoof

Headercistern

Hot waterstore

Pump

Check valve

Thermosiphon

Headercistern

Hot waterstore

Solar collector

Vent

Expansion

Solar collector

Air vent

Roof

Expansionvessel

Pressuregauge

Safetyvalve

Hot waterstore

Pump

Check valve

http://www.hse.gov.uk/legionnaires/index.htm


Solar electric (photovoltaic)

SOLAR ELECTRICNHBC guide to renewable energy May 2007

The technology Solar electric systems harness energyfrom the sun to generate electricity.

Solar electric panels or modules, whichincorporate photovoltaic cells madefrom semiconductor material, areinstalled at roof level. When sunlightreaches the semiconductor material,direct current is generated. In mostsystems, this is then converted intoalternating current by means of aninverter, which is fed into the dwelling’smains electrical system.

There are two main types ofphotovoltaic cell:

� Monocrystalline cells offer thehighest conversion of sunlight toelectricity but are expensive to produce.

� Thin film cells are considerablycheaper, but less efficient and solarger panel areas are needed togenerate significant power.

The traditional ‘building block’ of solarelectric power generation is thephotovoltaic panel or module. Thiscomprises a weatherproof doubleglazed metal frame, enclosing atoughened glass front plate and ametal or plastic back plate with solarcells sandwiched in between. Typically,solar electric panels are mounted ontoa metal support frame fixed to the roof(or walls) of a building.

Alternatives to photovoltaic panels arephotovoltaic slates and tiles, whichmake up the complete photovoltaic‘array’. These are interchangeable withordinary roofing components and canbe used to produce a solar electricinstallation, which is fully building-integrated. Photovoltaic cells can alsobe incorporated into glazing andcladding, skylights, conservatorypanels and external shading louvres.

Dedicated wiring is used to collect thepower generated by the solar electricpanel or array. In mains-connectedinstallations, the electricity generatedis fed to an inverter, which is connectedto the electrical consumer unit.

Design considerationsThe solar energy resource varies

across the UK (see ‘Annual total solarirradiation’ map at Appendix A). Thefurther north, the less solar energythere is and the greater is the area ofsolar electric panel required to capture it.

The rating of a solar electricinstallation is given by its peak poweroutput measured in kilowatts (kWp),which is defined according to a

standard formula. Typically 10m2 ofmonocrystalline cells are needed perkWp. The energy yield rule of thumbfor the UK is 750 kilowatt hours ofelectricity generated per kWp per annum.

Solar electric should be consideredfrom the outset in order to maximisethe benefits. Ideally, systems should bedesigned integrally with the building

3.1 Roof-mounted solar electric panels

3.2 A grid-connected system


Solar electric (photovoltaic)

SOLAR ELECTRICNHBC guide to renewable energy May 2007

layout and electrical services. This willmake the system more cost effective.

Solar electric panels should be sited onunobstructed roofs, ideally facing south,southeast or southwest. It is not advisableto install them on north-facing roofs.For south-facing panels, an inclinationof 45° offers optimum spring-summer-autumn overall performance.

It is possible to have separate east andwest-facing arrays at additional cost.Shadows from trees and chimneys, etc.will reduce the amount of energycollected although it may be possiblefor panels to be mounted onoutbuildings, etc. to avoid this.

Because their output reduces whenthey are dirty, solar electric panelsshould be inclined as steeply aspossible to ensure that rain and dirtrun off quickly. As photovoltaics arebased on solid-state technology theirmaintenance requirement is minimal.

The roof structure will need to bedesigned to accommodate the load ofthe panels – it may be necessary toseek the advice of a structuralengineer or the designer of the roof structure.

Planning permission may be requiredfor solar electric panels, althoughsystems can be designed to blend inwith the building. For example, ‘low’ or‘no profile’ arrays are designed to be

totally flush with the roof to be less conspicuous.

To install a grid-connected system, thelocal Distribution Network Operator(DNO) will need to be notified if thesystem output exceeds 16A per phase(Engineering Recommendation G83/1).The DNO is the company whichoperates the distribution network inthe local area, and may not be theelectricity supplier. To find out whichcompany the local DNO is, visit theBritish Photovoltaic Associationwebsite (www.pv-uk.org.uk).

Space will be required for theinstallation of the inverter and controlequipment, which is normally wallmounted adjacent to the electricalconsumer unit. Ventilation should beprovided around this equipment.

Installation tips � Ensure solar electric panels are

securely fixed to withstand windloads, etc.

� Weatherproof all penetrationsthrough the roof covering withsuitable flashings, purpose-madetiles, etc. Sealant is not suitable forthis purpose and will not besufficiently durable.

� Locate and install cables carefullyto minimise the risk of damage - the

wiring should not be thought of as‘only low voltage’ as solar electricpanels can generate DC electricityat over 100V. The photovoltaic DC,mains, ELV and signal cables shouldbe segregated.

� Fix permanent labels to wiring,junction boxes, etc.


� Provide operating instructions andmaintenance recommendations forthe homeowner.


� electrical safety (noting that somewiring may be live when the mainswitch on the consumer unit is inthe “off” position).

� working at height.



http://www.greenenergy.org.uk/pvuk2/

The technologyHeat pumps upgrade low temperatureheat extracted from the ground or airinto higher temperature heat that canbe used for space and water heating.

Heat pumps work on the sameprinciple as a refrigerator’s coolingcircuit - they absorb heat at a lowtemperature (from the surroundingground or air) and ‘upgrade’ it to ahigher temperature. Most heat pumpsare electrically driven and work byabsorbing ambient heat from the air orground surrounding the building anddepositing it inside at a high enoughtemperature to provide space heatingand/or hot water. In a typical system,for every unit of energy used to drivethe system, between 3 and 4 units ofheat are produced.

Because heat pumps require energy todrive them, the energy produced is notstrictly renewable. However, the pumpcan be run from a “green” source(electricity generated from renewableresources or purchased from a supplieron a “green” tariff) to minimise carbon emissions.

Heat pump performance is measured interms of Coefficient of Performance(COP), which is the ratio [heatdelivered ÷ compressor power input].

Ground source heat pumps Ground source heat pumps (GSHPs)extract ambient heat from the groundaround the building. The keycomponents of the installation are:

� a heat collection loop of continuousplastic pipe (containing antifreezesolution) and a circulating pump

� a factory-built packaged heat pump

� a low pressure hot water system,similar to a standard central heating system.

There are two types of GSHP collection loop:

� Vertical loops, lowered into deep(60m-100m) boreholes which arethen backfilled with suitable groutto prevent undesirable groundwatermigration, and

� Horizontal loops, laid out in slittrenches, (average depth 1.5 m)

‘Slinkies’ in trenches

Vertical bores

Ground source heat pump

Only one type of ground loop would be used in a system


Heat pumps (ground source and air source)

HEAT PUMPSNHBC guide to renewable energy May 2007

4.1 Ground source heat pump unit 4.2 Horizontal trench

4.3 Heat collection loop

4.4 Ground source heat pump unit

which are then backfilled with soil.One or two trenches up to 40m inlength may be needed with thenecessary length of pipe.

Air source heat pumps Air source heat pumps (ASHPs) extractambient heat from the air outside thebuilding. The key components of theinstallation are:

� a packaged heat pump andcirculating pump

� a low pressure hot water system,similar to a standard central heatingsystem (the system may be chargedwith antifreeze solution to avoid therisk of freezing).

ASHPs are either installed externallyon roofs or in gardens. Alternativelythey may be located inside the buildingwith the outside air circulated vialouvres and ducts. They are generallyless expensive to install than GSHPsalthough their day-to-day performanceis dependent on weather conditions.

Design considerationsThe heat pump and heating systemshould be designed from the outset inorder to optimise performance.

Heat pumps are best suited tobuildings with a high thermal mass,which tends to smooth the demand forheat and allows the device to operateas a ‘base load’ heat source. A highthermal mass also allows the heatpump to be run on cheap rateelectricity overnight before thebuilding ‘coasts’ for a while after thepeak daytime rate period begins.

Heat pumps do not work well inbuildings with low thermal mass unlessa thermal store is incorporated in thelow-pressure hot water system circuit.

Because of the relatively high capitaland running costs of heat pumps, theymay not prove cost-effective when amains natural gas supply is available.

Heat pumps are not generally sized tomeet the peak heat demand, on theassumption that any heat shortfall willeither be met by incidental gains (fromelectrical appliances, etc.) or satisfiedby a ‘boost’ heater.

Where the heat pump is to be backedup by another heat source, the controlof that source must be interlocked toensure that it can never operate as thepriority or ‘lead’ device.

The best COPs are achieved by runningsystems at low temperatures - thelower the flow and return designtemperatures (e.g. +40°C/+30°C), thebetter. For this reason, they are ideallysuited for use in conjunction withunderfloor heating systems, althoughthey can also be used with ’lowtemperature‘ radiators.

The COP of a heat pump runningsufficiently hot to deliver domestic hotwater at 50°C - 60°C will beconsiderably lower than its COP inspace heating mode. In view of this,there is a view that heat pumps shouldonly be used for space heating andthat domestic hot water should beheated by a solar thermal system withan auxiliary backup. Conversely, analternative view is that, because oftheir capital costs, heat pumps shouldbe used for both space and domestichot water heating, but never for bothduties at the same time. If a heat pumpis used for both duties separatetemperature controls should be fitted

to allow the higher temperature outputonly when in domestic hot waterheating mode.

The position of all equipment includingthe heat pump, hot water cylinder andthermal store (where fitted) should becarefully considered. Adequate space,load-bearing capacity and access formaintenance should be provided.

The rating of the mains electrical powersupply may need to be increased toaccommodate the electrical currentdrawn by the heat pump.

Ground source heat pumps

The type and design of the collectionloop used with a GSHP will depend onthe nature of the subsoil and geology.This should be established byundertaking an investigation todetermine the geotechnical and groundwater conditions.

The layout of horizontal collector loopsshould be designed to suit the shape ofthe house plot and boundaries.

Where land has been remediated careshould be taken to ensure that cappinglayers, etc. (where present) are notdamaged or compromised.




4.4 External air source heat pump unit




Air source heat pumpsThe location for the installation of anASHP needs to be considered carefullyas they can generate significant noisein operation.

Consideration should be given to theiraesthetic appearance of externalASHPs and planning permission maybe required.

Installation tips � Consider drilling vertical bore holes

and installing the pipework loop atan early stage in the construction ofthe homes – heavy plant is neededand it can be a messy operation.

� Install the pipework loop carefullyand protect it from damage duringbackfilling and after installation.

� Test all pipework after installationand backfilling to ensure that it is sound.

� Fix permanent labels and flowarrows to pipework, valves, etc.




� the risk of Legionnaires’ disease -this is a potentially fatal form ofpneumonia that can thrive in

purpose built water systems unlessthey are properly managed. Furtherguidance can be found atwww.hse.gov.uk/legionnaires/index.htm and in the HSE’s ApprovedCode of Practice & Guidancedocument, L8

� electrical safety

� for GSHPs, damage to servicesbelow ground, membranes, cappinglayers, etc. (where present).



http://www.hse.gov.uk/legionnaires/index.htm

The technologyWind turbines harness energy fromwind and convert it into electricity.

Wind passing over the blades causesthem to rotate and the blade rotor axlepasses through an electricitygenerator. The electrical output ispassed through a control system andthen an inverter which is connected tothe dwelling’s mains electrical system.The inverter ensures that thealternating current electricity producedby the turbine is synchronous and inphase with the mains electrical supply.

Generally, wind turbines yieldmaximum power during winter when ahousehold’s demand is typically highestbut obviously, the yield on a particularday is variable.

Design considerationsThe wind energy resource variesgreatly across the UK and it canchange significantly even within asmall local area due to the generaltendency of buildings to spoil the freeflow of wind.

It is important to work out theanticipated energy yield from a givensize of wind turbine based on theannual average wind speed for thelocation. This is the basis for derivingan estimate of the annual energy yieldfrom the wind turbine’s ‘nameplate’rating. However, a local appraisal of theeffect of trees and buildings on windspeed and turbulence must also betaken into account. ’NOABL‘ is theDepartment of Trade and Industrybased resource used by most windturbine suppliers when estimating sitepotential. See www.bwea.com/noabl formore information.

Wind turbines should be considered atthe start of any building project inorder to maximise the benefits. Ideally,systems should be designed integrallywith building layout (including thelocation of roof-level features such aschimneys, flues, dormers, etc).

The ideal position for a building-mounted wind turbine is:

� as far as possible from major ‘wind-spoiling’ features such as trees oradjacent buildings.

� on the side of a building facing theprevailing wind (normally southwestin most of the UK) so that it isnormally upwind of it, away fromchimneys, flues, etc.

� as high up as possible.

It is important that the structure of thebuilding is designed to accommodatethe load form the wind turbines andany vibration – it may be necessary toseek the advice of a structural engineer.

Wind turbines should be located sothat they can be safely accessed for maintenance.

Space will be required for the

installation of the inverter and control

equipment, which is normally wall

mounted adjacent to the electrical

consumer unit. Ventilation should be

provided around this equipment.

Planning permission may be required

for wind turbines.

To install a grid-connected system, the

local Distribution Network Operator

(DNO) will need to be notified if the

system output exceeds 16A per phase

(Engineering Recommendation G83/1).


Wind turbines (small scale, building mounted)

WIND TURBINESNHBC guide to renewable energy May 2007

Utility Service

Wind Turbine

Home Power Appliances

Meter

Inverter

5.1 Small scale, building mounted wind turbines

5.2 A small scale wind turbine system

http://www.bwea.com/noabl/

Wind turbines (small scale, building mounted)


NHBC guide to renewable energy May 2007 WIND TURBINES

The DNO is the company whichoperates the distribution network inthe local area, and may not be theelectricity supplier. To find out whichcompany the local DNO is, visit theBritish Photovoltaic Associationwebsite (www.pv-uk.org.uk).

Installation tips� Ensure wind turbines are securely

fixed to withstand wind loads, etc.

� Locate and install cables carefullyto minimise the risk of damage - thewiring should not be thought of as‘only low voltage’ as wind turbines

can generate electricity at over200V. The ‘raw’ AC, mains, ELV andsignal cables should be segregated.

� Fix permanent labels to wiring,junction boxes, etc.



Health and safetyCare should be taken to address all

issues, including:

� electrical safety (noting that somewiring may be live when the mainswitch on the consumer unit is inthe “off” position)

� working at height.





Biomass (domestic biomass heating systems)

BIOMASSNHBC guide to renewable energy May 2007

The technologyBiomass is the oldest form ofrenewable energy and is derived frombiomass fuels such as trees and crops.It can be processed by burning,fermentation or extraction to providethe energy for domestic heating.Modern wood-fuelled systems offer aclean, highly efficient alternative tofossil fuel systems.

The two main types of biomass heatingdevice are:

� ‘automatic’ stoves - normally usedfor producing radiant heat inhouses, and

� boilers – normally used for largerinstallations, including heatingblocks of flats.

Depending on the make and model,biomass stoves and boilers may beused to provide space heating only orspace heating and domestic hot water.

The three main types of biomass fuel are:

� logs (cut to size with a maximumacceptable moisture content).

� wood chips or wood waste (againcut to size with a maximumacceptable moisture content).

� wood pellets (manufactured fromwood waste to a tight specificationcovering dimensions, moisturecontent and calorific value).

Design considerationsSome biomass devices do not have thefacility to shut down and thenautomatically restart according to heatdemand. These systems have a certainminimum fuel burning rate – andtherefore a minimum heat output whenthey are ‘slumbering’ (i.e. alight, butthe control system is not calling forheat) and are suited to buildings with ahigh thermal mass.

A great advantage to biomasstechnology is that the capitalexpenditure per dwelling can bereduced by installing a central biomassboiler installation which serves anumber of properties via a heatdistribution network. It is also muchmore energy efficient and

environmentally friendly to run a singlecentral boiler at low output than it is tohave numerous small boilers eachalternating between slumbering andlow firing.

The provision of biomass heatingsystems may need to be discussed withthe planning authority becauseadditional buildings may be needed forfuel storage. Also access will need to

be provided for fuel deliveries andchimneys will be required.

As biomass heating devices requiremore in the way of infrastructure thantheir oil or gas equivalents, designersshould always question their suitabilitybefore installation. Some devices canbe noisy or require regular refilling.Moreover, not all homeowners have theability nor the inclination to receive

To Chimney

Wood Pellet Boiler

Auger Drive Wood Pellets

Sacks of pellets stacked on a pallet (as delivered)

Stoker

RotaryValve

LPHW

BUILDING FUEL STORE

6.1 A biomass boiler

6.3 A biomass boiler system

6.2 A biomass stove


Biomass (domestic biomass heating systems)

BIOMASSNHBC guide to renewable energy May 2007

and/or handle fuel, clean the deviceinternally (typically a weekly task) anddispose of the ash.

Biomass should be considered at thestart of any building project in order tomaximise the benefits. Ideally, systemsshould be designed integrally withbuilding layout, building structuralspecification and electrical services,and the following should be consideredfor a successful installation:

� dimensions and weight ofequipment and auxiliaries

� surrounding building fabric:proximity/flammability rules

� combustion air supply

� chimney/flue: location and provisionfor cleaning

� pipework for domestic hot waterheating only OR for low pressurehot water for space heating anddomestic hot water, whereappropriate

� provision of ‘dump’ heat emitter fordissipation of ‘slumbering’ heatoutput and/or inclusion of a thermalstore in the low pressure hot water

circuit, where appropriate

� provision of access for deliveringfuel and space for storing asufficient quantity.

Where biomass heating equipment is tobe backed up by another heat source,the control of that source must beinterlocked to ensure that it can neveroperate as the priority or ‘lead’ device.

Most biomass heating systems requirea mains power supply to operate thecontrols, fans, fuel feeds, etc, and it isimportant to segregate mains andsignal/control cables.

Installation tipsEnsure the back-up heat source canoperate under master/slave controlfrom the boiler controller in order tooptimise its energy efficiency.

Remember the easiest installationoption may not be the most beneficialfor system users. The biomassstove/heater/boiler will probably befitted with its own control panel. Ifspace heating and domestic hot waterheating are to be controlled by aseparate programmer, consider how

much easier it might be for thehomeowner and the maintenanceengineer to understand/analyse systemoperation if the two displays are adjacent.

Provide operating instructions andmaintenance recommendations for the homeowner.


� electrical safety

� fire safety - heating equipmentinstallation including chimney andfuel store. Smoke detectors, firedetectors, CO detectors, anti-burnback devices (to prevent fuel instorage from being accidentallyignited), quenching devices.




Appendix A - Annual total UK solar irradiation map (kWh/m2)

APPENDIX ANHBC guide to renewable energy May 2007

1200

1100

1000

900


Appendix B - Typical system costs

APPENDIX B & CNHBC guide to renewable energy May 2007

System Type Typical System Typical Installed Cost

Flat plate solar thermal 2.5m2 £1,750

Evacuated tube solar thermal 2m2 £2,000

Solar electric panels 2kW £10,000

Ground-source heat pump 4kW £7,000

Small scale wind turbine 400W £2,000

Pellet boiler 6kW £6,000

Pellet stove 3kW £4,500 per kW

Source: BRE (based on figures from the Clear Skies and Low Carbon Buildings Programmes)

Appendix C - UK Microgeneration Certificate Scheme

This new scheme, currently underdevelopment by BRE, will underpin theDTI’s grant scheme, the Low CarbonBuildings Programme. Grants will onlybe available to applicants using bothproducts and installers certificatedunder the UK Microgeneration Certification Scheme.

The new scheme will evaluate productsand installers against robust criteriafor each of the microgenerationtechnologies, providing greaterprotection for consumers and ensuring

that the Government’s grant money isspent in an effective manner.

The aim is to help build a rapidlygrowing microgeneration industrybased on quality and reliability, whichwill make a substantial contribution tocutting the UK’s dependency on fossilfuels and its carbon dioxide emissions.Further information can be found atwww.ukmicrogeneration.org andwww.greenbooklive.com.

The UK Microgeneration CertificationScheme will operate according to a set

of Environmental Standards (ES).These are free and publicly available atwww.ukmicrogeneration.org andwww.greenbooklive.com. For example,ES3003 covers small scale windturbines and other renewabletechnologies are also covered in the series.

These standards will be regularlyupdated and include all relevant BS &EN standards within them and will be avital resource for builders.



http://www.greenbooklive.com

http://www.greenbooklive.com


Appendix D - Relevant standards and additional information

APPENDIX DNHBC guide to renewable energy May 2007

Regulations and Standardsapplicable across the technologiesBuilding Regulations 2000, England and Wales

Building (Scotland) Regulations 2004

Building Regulations (Northern Ireland)2000

Control of Substances Hazardous to HealthRegulations (COSHH) 1994

Electronic Equipment Regulations (RoHS)2006 SI 1463

Pressure Equipment Regulations (PED) 1999

Water Supply (Water Fittings) Regulations 1999

BS EN 60335-1:2002 Household & similarelectrical appliances - Safety - Part 1:General requirements

BS7671:2001 Requirements for Electrical Installations

Energy Networks Association EngineeringRecommendation G83/1: Recommendationsfor the connection of small-scaleembedded generators (up to 16A perphase) in parallel with public low-voltage distribution networks

European Directives applicableacross the technologiesAirborne Noise: 86/594/EEC

Construction Directive: 89/106/EEC

Electromagnetic compatibility (EMC)Directive: 89/336/EEC

Energy Labelling Directive: 92/75/EEC

Energy Using Products Directive (EuP):2005/32/EEC

Low voltage (LV) Directive: 73/23/EEC

Machinery Directive: 98/37/EEC

Standards for solar thermal systemsBS 7431:1991 Method for assessing solarwater heaters. Elastomeric materials forabsorbers, connecting pipes and fittings

TS 12977-3:2001 Performancecharacterisation of stores for solar heatingsystems

TS 12977-2:2001 Thermal solar systems andcomponents. Custom built systems. Test methods

TS 12977-1:2001 Thermal solar systems andcomponents. Custom built systems.General requirements

BS EN 12976-2:2001 Thermal solar systemsand components. Factory made systems.Test methods

BS EN 12976-1:2001 Thermal solar systemsand components. Factory made systems.General requirements

BS EN 12975-2:2001 Thermal solar systemsand components. Solar collectors. Test methods

BS EN 12975-1:2000 Thermal solar systemsand components. Solar collectors. General requirements

BS 7074 Application, selection andinstallation of expansion vessels andancillary equipment for sealed water systems

BS 5449, BS EN 12831 BS EN 12828Specification of forced circulation hotwater central heating systems for domestic premises

CIBSE Domestic Building Services Panel -Design Guide for solar water heating.

Standards for solar electric systemsBRE digest 238, Photovoltaics: integrationinto buildings, 2004

BRE Digest 489, Wind loads on roof basedphotovoltaic systems, 2004

BRE Digest 495, Mechanical installation ofroof-mounted photovoltaic systems, 2005

Understanding building integratedphotovoltaics , TM25, CIBSE, 2000.

Standards for heat pump systemsBS EN 14511:1-4:2004, Air conditioners,liquid chilling packages and heat pumpswith electrically driven compressors forspace heating and cooling.

BS 7074:1-3:1989, Application, selection andinstallation of expansion vessels andancillary equipment for sealed watersystems. Code of practice for domesticheating and hot water supply

BS EN ISO 5198:1999 Centrifugal, mixedflow and axial pumps - Code for hydraulicperformance tests - precision class (AMD 10668)

BS 8207:1985 Code of practice for energyefficiency in buildings (AMD 8151)

BS 6880-1:1988 Code of practice for lowtemperature hot water heating systems ofoutput greater than 45kW. Fundamentaland design considerations

BS 6700:2006Design, installation, testingand maintenance of services supplyingwater for domestic use within buildingsand their curtilages - Specification

BS EN 378:1-4:2000, Refrigerating systemsand heat pumps - Safety andenvironmental requirements. Basicrequirements, definitions, classification andselection criteria

Ground source heat pumps: a technologyreview , TN18/99 BSRIA,1999

How to design a heating system,Knowledge Series 08, CIBSE 2006.

Standards for wind turbine systems

BS EN 61400-1:2005 Wind Turbines. Design Requirements

61400-2 BS EN 61400-2:2006 Windturbines. Design requirements for smallwind turbines

61400-11 BS EN 61400-11:2003 Wind turbinegenerator systems. Acoustic noisemeasurement techniques

61400-12 BS EN 61400-12-1:2006 Windturbines. Power performancemeasurements of electricity producingwind turbines

Standards for biomass systems

BS 4543-2:1990 Factory made chimneys.Specification for chimneys with stainlesssteel flue linings for use with solid fuelfired appliances (AMD 8380)

BS 6461-1:1984 Installation of chimneysand flues for domestic appliances burningsolid-fuel (including wood and peat). Codeof practice for masonry chimneys and flue pipes

BS 1846-1:1994 Glossary of terms relatingto solid fuel burning equipment. Domestic appliances

BS 5588-1:1990 Fire precautions in thedesign, construction and use of buildings.Code of practice for residential buildings.

Relevant associations

British Photovoltaic Association www.pv-uk.org.uk

Renewable Power Association www.r-p-a.org.uk

British Wind Energy Associationwww.bwea.com

Heat Pump Association www.feta.co.uk/hpa

UK Heat Pump Networkwww.heatpumpnet.org.uk

Solar Trade Associationwww.greenenergy.org.uk/sta

Major PV demonstration programmewww.est.org.uk/solar

Centre For Alternative Technologywww.cat.org.uk


http://www.r-p-a.org.uk/home.fcm

http://www.bwea.com

http://www.feta.co.uk/hpa/

http://www.heatpumpnet.org.uk

http://www.greenenergy.org.uk/sta/

http://www.energysavingtrust.org.uk/housingbuildings/funding/solarpv/

http://www.cat.org.uk/index.tmpl?refer=index&init=1


Appendix E - Acknowledgements

APPENDIX ENHBC guide to renewable energy May 2007

The following organisations are thanked forgiving permission to reproduce their images:

Image Credit

2.1 BRE and Energy Saving Trust

3.1 BRE

4.1 EarthEnergy Limited



4.4 Dimplex

5.1 Swift

6.1 Dulas Ltd.

6.2 Centre for Alternative Technology

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