Renewable Heat/PassivHaus - Gary Wilburn, HPW

Renewable Heat / PassivhausGary Wilburn

SustainableConstructionNetwork

GW-SISCo (Passivhaus) 31/1/11 17:04 Page 1

Heat - generating low and zero carbon technologies


1. Ground source heat pumps (GSHP)� Ground remains at a fairly constant temperature (10-12°C)

all year round at approximately 1.5 meters below the earth’s surface.

� GSHP extracts heat from the ground to provide space (and water) heating to any building type.

� Air source and water source heat pumps are also available.


GSHP: three main elements1. Ground loop. - Comprised of lengths of pipe buried in the ground,

either in a borehole or a horizontal trench.

2. A heat pump. - Evaporator - Compressor - Condenser.

3. Heat distribution system. - Under floor heating or radiators for space heating and in some cases water storage for hot water supply.


Ground loop� Water (or other fluid) is circulated through pipes underground

and passes through a heat exchanger that extracts heat and is circulated through a building (often underfloor heating,fan coils or oversized radiators).

� Pipe work containing heat transfer fluid is either laid in ‘horizontal trenches’ or in a ‘vertical borehole’ and transfers the heat from the ground to be used for space or water heating.


GSHP Efficiency� The efficiency of a GSHP system is measured by the coefficient of performance (CoP)

� CoP= ratio of ‘units of heat energy output’ for ‘each unit of electricity used’ to drive the compressor and pump

� Typically every unit of electricity used to pump the heat, 3-4 units of heat are produced. Therefore, typical CoPs range from 3 to 4


2. Solar water heatingSolar thermal hot water

� Converts energy from the sun to provide useful heat. Their most common application in the UK is to provide hot water

� Comprises of a collector with a heat transfer fluid mounted on the roof of the building. This fluid is heated by the sun and the heat is transferred by a heat exchanger to a separate water storage tank or a twin coil hot water cylinder inside the building, which is used to provide hot water


Solar thermal hot water: components1. Solar panelsCollect heat from the sun's radiation and are usually fitted on the roof

2. Heat transfer systemUses the collected heat to heat water

3. Hot water cylinderStores the hot water that is heated during the day and supplies it for use later


Solar thermal hot water: types of system1. Flat bed panels

- Realize temperatures of 35ºC- Good for supplying pre-heated water for a gas boiler

or immersion heater

- Commonly used and cheaper technology

2. Vacuum tube

- Suited to cooler climate due to reduced heatloss

- Can heat water to 60ºC. May require no additional heating

- Should be linked to a storage facility to store excess warmth in summer for winter season.

- More expensive though generally claim to provide better winter performance


3. Biomass heatingAny biological mass derived recently from plant or animal matter, including:

� Material from forests (roundwood, cutting residues and other wood brashings)

� Dedicated crop-derived biomass (woody short-rotation coppice energy crops – willow and poplar, grass crops-miscanthus, timber crops)

� Dry agricultural residues (straw, poultry litter) and:

� Wet waste (slurry, silage), food wastes, industrial and municipal waste


Biomass: Low carbon source of fuel� Biomass is considered carbon neutral or low carbon if

materials are derived from sustainable sources.

� Some net emissions result from cultivation, harvesting, processing and transportation of fuel.

� Local availability of fuel is important for reducing associated net carbon emissions.


Lifecycle Carbon Emissions comparison� These figures include raw material supply, production,

transport, energy generation and eventual disposal

� Biomass more efficient when used for space heating as compared to electricity generation

� Solid Biomass for heating typically gives reductions of about 90% as compared to fossil fuels


Passivhaus United Kingdom


Passivhaus – a comfort standard?� No draughts

� No cold radiant

� No summer overheating

� Fresh air always

� Whole house warm - no hypothermia

� Fuel Poverty eliminated


Passivhaus – Simplicity� Extra insulation

� Extra panes of glass

� Full ventilation system� And clever design…

- Site layout- Insulation and thermal bridges- Solar gain and protection- Air tightness and ventilation


Retro-fit housing...� Passivhaus targets for a retro-fit home

� Prewett Bizley Architects

� 22 kWh / m2 achieved

� Victorian terrace

� MVHR and air tightness challenges

� Owned by a Building Physicist!


Culford Road London


Batschuns House Austria


Sourcing sustainable products & technologies


Building Materials Showroom Austria


Building Materials Showroom Austria


Case studies: Designing to a higher level


Passivhaus School Austria


Passivhaus Construction� Use of bioregionally sourced materials

� Manufactured, high quality solution

� Off-site modular format

� Maximising insulation, minimising energy use

� Known technology and construction details


Ludesch Community Building Austria


Wolfort Housing Austria


Swimming Pool Dornbirn Austria


Wolfort Housing Switzerland


Swimming Pool Dornbirn Austria


Sohm Factory Switzerland


York stone barn retro-fit� Low carbon conversion� HPW designed� GSHP� Triso super 10 insulation� POE study ongoing� Listed exterior� Owner living through building works


Domestic retro-fit (before)


Elevation G (NORTH 1)

Domestic Retro-fit (after)

Charts created using heating system data created by DSM in IES and lighting data


Paultons ParkWorking closely with the client team at Paultons, HPW have created a low carbon, wild flower roofed and naturally ventilated indoor play area

The building will form the centre piece to the new attraction at the well known amusement park for ‘Peppa Pig’ and his friends. With underfloor heating, wind catchers, super insulated building shell, rainwater harvesting, hybrid frame and locally sourced timber cladding the 10,000 sq.ft facility is due to open in spring 2011


Paultons Park Site progress


Paultons Park Site progress


Thank you... any questions

SustainableConstructionNetwork


Renewable Heat/PassivHaus - Gary Wilburn, HPW

Documents

heat exchanger

units of heat

collected heat

useful heat

water source heat pumps

solar panelscollect

heat transfer fluid

heat energy output