Heat Exchange

This section is the place to look for information on how to get heat energy out of either:

  • the surrounding air.
  • the ground beneath your lawn.
  • the ground beneath your patio.
  • the mud and water at the bottom of a large pond or lake.

Of these, air temperature is the most variable; but even in winter it rarely goes below -15°C and so it still has plenty of heat that a Heat Exchanger can make use of - think of the heat that warms the side of your Fridge and Freezer. In general, temperatures become warmer and are more stable the deeper one goes. At a depth of 10m plus, the soil and rock will have a temperature of around 10 - 14°C throughout the year; not enough for a geothermal power station, but quite sufficient for a heat pump.

Heat Exchangers do require electricity both to run the circulating pumps and the compressor. The latter has to work harder the lower temperature of the incoming air or water, or the higher the room temperature required. Thus although Heat Exchangers can achieve a conversion rate of 4 units output for every 1 unit of electrical input, this can fall to 2:1 or even less for an Air Source Heat Pump on very cold winter nights.

The notes do warn that it is essential to have a large accumulator tank in order to provide a store of hot water, for extra demand or to warm the house on a cold morning.

Under the new RHI Premium Payments Scheme (RHI = Renewable Heat Incentive Scheme), the Energy Savings Trust is to run an initial scheme to be put in place from 1 August 2011 to March 2012. In this £12million scheme any householder can receive the following for their main home, providing that they have 250mm of insulation and cavity wall insulation if appropriate:

  • a £300 voucher towards solar thermal technology,
  • a £950 voucher for a biomass boiler for homes not heated by gas from the grid
  • a £850 voucher for an air source heat pump or
  • a £1250 voucher for a ground source heat pump

NBThis scheme is cash limited, so it is a case of first-come, first-served. However, it is anticipated that from next year the scheme will be extended. The first link will take you to the site from which you can apply for the RHI premium vouchers. nnfcc.co.uk/ and the next link takes you to a list of sites from which you can delve deeper into DECC's schemes. energysavingtrust.org.uk/

Please mention TigerGreen whenever you contact any of our linked Top Providers, Suppliers and Contractors.