Key Issues

As well as this the Government’s intention is for all new homes to be zero carbon by 2016 with a major progressive tightening of the energy efficiency building regulations - by 25% in 2010 and by 44% in 2013 - up to the zero carbon target in 2016.

This drive will highlight the need for renewable technologies such as ground source heat pumps, to be effectively integrated into new buildings. The DTI’s report ‘The potential for Micro-generation’ suggests that 28,000 heat pumps will be installed by 2012, a ten-fold increase on current volumes.

The interest in heat pump technology is therefore increasing and to provide an effective solution it is important that the key issues on how these systems are integrated into buildings are understood.

As the country’s only manufacturer of a full range of ground source heat pumps, Kensa Engineering offers a solution specifically designed for the UK market. The company provides industry-leading advice and guidance on how heat pumps can help lower the CO₂ emissions of buildings and meet the requirements of Part L (Conservation of Fuel and Power) of the Building Regulations, help meet level three of the Code for Sustainable Homes and lower the tenants heating costs. Particular attention is paid to application engineering to ensure each installation enables trouble-free performance.

The following section covers key issues that should be considered with heat pumps in the Social Housing Sector such as:

Funding and the Renewable Heat Incentive for Social Housing
Heat Distribution Systems and Domestic Hot Water
Part L Compliance Strategies
Installation Options
Typical Project Costs

1. Funding and the Renewable Heating Incentive for Ground Source Heat Pumps

The Renewable Heat Incentive (RHI) scheme is currently out for consultation hence the details here may change before the scheme is launched in April 2011, however the main points are not expected to change in any major way. In February, the Government produced a consultation document on the proposed Renewable Heat Incentive (RHI) scheme. This consultation sets out the Government’s proposals on the design and operation of the Renewable Heat Incentive, with the aim of providing financial support that encourages individuals, communities and businesses to switch from using fossil fuel for heating, to renewable technologies and sources.

RHI payments to be claimed by, and paid to, the owner of the equipment. The RHI will be available to householders, local authorities and social landlords as well as the public, industrial and commercial sectors. All installations commissioned after 15th July 2009 will be seen as a “new installation” and will be eligible for the RHI.

Payments will be paid over the estimated life of the equipment (for Ground Source 23 years) and will be inflation linked and guaranteed.

Example of the expected RHI returns:-

Semi-detached Property with 2 bedrooms and an annual space heating load of 8,998kWh/year and DHW load of 3,742kWh/year. The below figures are an estimate only.

2. Heat Distribution Systems and Domestic Hot Water

Heat pumps work most efficiently delivering water at the lowest possible temperature into the heat distribution system. For this reason, underfloor heating – with its larger heat emitting area - has generally been favoured, however the minimal heat demand typical to many social houses means that radiators can be used. If radiators are selected, they should generally be designed with a flow temperature of 45ºC, which means they will need to be slightly larger than radiators linked to a conventional boiler.

Underfloor heating should be considered if the floor construction features a screed layer since the flow temperature could generally be reduced to around 30-35ºC. The likelihood of screed being used is far greater within traditionally built apartment developments than two storey dwellings with joisted first floor constructions. Where suspended timber floors are present, any underfloor heating pipework, typically installed within the joist void, would need to be embraced by a steel heat transfer plate, which not only increases cost but also slows the build programme. Since the flow temperature into these underfloor circuits would need to be increased to around 45ºC (to drive the heat through the overlying chipboard and final floor finish), there is no greater operating efficiency than if the heat pump was serving radiators.

Any Kensa heat pump can be linked to a mains pressure cylinder to provide domestic hot water although the required output temperature – 45-50ºC – will certainly impact efficiency. One alternative is to provide a mains pressure cylinder complete with immersion heaters and, if possible, link to an Economy Seven, or preferably, an Economy Ten tariff so the water can be heated during low cost periods. If only Economy Seven is available, a larger cylinder might be required to reduce the occasions when higher priced electricity is required to produce hot water. All cylinder manufacturers provide models which can receive an input from solar panels, if installed, to reduce dependence upon electricity.

Page 2 >