WOODFUEL FOR THE CONSTUCTION INDUSTRY Architects Point of View + Building Regulations

Wood as a fuel Multi use of wood fire in the home Wood fire one of longest standing forms of heating in human history Simple wood fired room heaters to supplement central heating – independence Burning wood logs gives connection to nature + sense of belonging Burning wood can reduce the potential impact of global warming and dependence when compared to fossil fuels.

Considerations for the designer Advantages of wood fuel House design Wood storage

Context Context with better performance building 4 primary design parameters - They are solar orientation, insulation, air tightness and thermal mass.

General Categories 1. New Build Single House Primary Heat Source Stott House Log cooker ( Rayburn) Pellet boiler Pellet Stove Logs stove with back boiler 2.Single retrofit to thermally inefficient building Parrot Gasification log boiler 3. Larger single structure Extension to FCS Office DingwallWood Chip boiler with bulk storage 4.Larger group houses / mixed use ServitePellet boiler with accumulator tank + hopper All above require different approaches

Costs The capital cost of wood-fuel system V Lifetime running cost Boiler room and fuel store size Installation Costs Grants and Incentives

Potential Cost Savings on fuel Peak electricity 13p per KW/h 1 litre oil on average = 60KW/h of energy 6p per KW/h 1 tonne pellets = 4800 KW/h of energy3p per KW /h ( based on £160 a tonne, min 4 tonne delivery from Balcas)

System comparisons Room Heater stove of feature stove boiler Hopper Capacity – 15 – 53kg Average Refill Time – 1-2days Boiler Location – internally Average approximate cost - £ £7000 Fed – manually with pellets. Gasification Log Boiler Hopper Capacity –180kg + Average Refill Time – dependant on size of thermal store Boiler Location – utility / garage / shed Average approximate cost - £11000 Fed – manually with wood logs Stove boiler Hopper Capacity – 70 – 180kg Average Refill Time – 2-3days Boiler Location – utility / garage Average approximate cost - £5500 Fed – manually with pellets. Pellet boiler with bulk storage Hopper Capacity – 3 – 6 tonnes Average Refill Time – 6 months – a year Boiler Location – utility / garage / shed Average approximate cost - £15000 Fed – suction / auger, pellets fed from lorry.

Potential C02 Savings CO2 emissions per kilowatt - hour (g/kWh) Wood fuel 25 Wind energy 8 Gas 194 Oil 265 Coal 291 Section 6.1 of the Building Regulations

Boiler Selection Space Size of fuel store Access Fuel supply Efficiency Operation and maintenance

Bulk storage of woody biomass fuel Consideration of storage requirements at early stage in design process Design must allow for: Access for large eight wheeled vehicles Direct delivery into store by tipping / vacuum Fuel storage for up to 50m3 chip / 4 tonne pellet in one delivery Design must avoid: The need for one off specialist vehicles Small fuel stores requiring constant refuelling – this adds £s to the fuel cost. Two stage handling ie chipping and then filling the fuel store. Bulk handling takes time and costs money Storage provision relative to number of deliveries. Storage space from building Storage Protection

Building Regulations The following works require a building warrant: A building exceeding 8m2 in area. A building containing a flue, a fixed combustion appliance installation does require a building warrant Any work associated with a solid fuel appliance having an output rating more than 50 kW Any work associated with a chimney, flue-pipe or constructional hearth. For example: 1. If retro fitting a wood fuel stove or boiler into an existing house this will require a warrant as the work will involve fitting a flue unless there is an existing chimney that could be used. 2.Similarly a small dedicated external boiler room with hopper will require a warrant as they may be over 8m2 and will contain fixed combustion appliances and flues. 3.Replacing an existing boiler with stove with one of the same kind will not require a warrant.

See guidance note for further info from the Domestic 2009 building regulations: Storage of woody biomass fuel - accommodation + safety Storage vessels, pipework and controls Chimney + Hearth Design Air Supply / Extraction Ventilation Distances to combustible materials Commissioning + Installation Building regulations also apply to other aspects of the work such as electrical installation and plumbing work in connection with the system

CASE STUDY 01: Single New Build thermally efficient 2 bedroom house, Farr, Inverness Boiler Specification: Rayburn solid fuel Heat ranger 355 SFW for cooking / domestic hot water and central heating. Fuel Type: Wood log manual feed Output: 12kW Efficiency: 85 % Accumulator tank: 250 litre internally housed Fuel Delivery : On site Wood-fuel Store capacity: External log wood shed. Back Up System: 4.4m2 solar collector + immersion CO2 emissions : 0.4 tonnes per year

CASE STUDY 02: Single house -retrofit to thermally inefficient building Batch burning, quick burst and trap energy in accumulator tank Boiler: Specification: Baxi Log Boiler Fuel Type: Wood Logs -Manual feed Output: 50KW Efficiency: 90% Accumulator tank: 2500 litre Woodfuel Store capacity: 3m3 Boiler Housed : Timber Outbuilding

CASE STUDY 03: Extension to FCS Office Dingwall, Wood Chip Heating supplies 2 no heating circuits + hot water to building Boiler Specification: Froeling Turbomatic Wood Chip Boiler Fuel Type: Pellet – Wood Chips Output: 35kW Efficiency: 90% Accumulator tank: 1500 litre Woodfuel Store capacity: 30m3 Back Up System: Existing Oil boiler Boiler Housed : Externally

CASE STUDY 04: Servite Housing Association (32 dwellings). Achieved a prestigious "Excellent" rating for sustainability, achieving the highest score in Scotland in areas of sustainability including energy + CO2 performance. Boiler Specification: 3no Okofen 56KW Fuel Type: Pellet: Wood Pellets Output: 56kW each Efficiency: 90% Accumulator tank: 3no 2000litre Wood fuel Store capacity: 6 tonnes per hopper Back Up System: If one boiler goes down then the other two are linked to circuit until fixed.