Renewable Cooling
BRE has published its Study on energy use by Air Conditioning which was commissioned by DECC, now BEIS. This two year study concludes that up to 10% of all UK electricity use is for air conditioning and cooling. Much of this is used in offices and retail space, with a high proportion being used in London and the South East. Because of the firm trend toward increased use of cooling the proportion of UK electricity used for cooling is likely to rise.
The standard method of providing cooling is fundamentally inefficient as it is based on heat exchange with hot air. Heat is deliberately wasted into the atmosphere, instead of being stored for re-use.
Renewable Cooling is the radical alternative to providing cooling by using roof mounted chillers to "waste" heat into hot air on warm summer days.
Traditional cooling is expensive in electricity and in carbon emissions because it employs the very inefficient process of trying to loose heat into heat. The coefficient of performance of an air conditioning chiller can be as low as 2 on a hot day.
The alternative is to use a heat pump to allow the transfer of heat from the building into the cold ground beneath the building. The coefficient of performance of a ground source heat pump in these favourable conditions can be as high as 20.
The opportunity to provide Renewable Cooling is greatest in a building which already employs a ground array to provide ground source heating. With a heat source, a heat pump and a heat delivery system already in place the additional capital cost of providing Renewable Cooling is limited.
Heat Recycling
A by-product of using Renewable Cooling is heating up the ground – the additional temperature in the ground will provide an automatic benefit to the heat pump when it is reversed in winter to provide heating. The merits of Heat Recycling between summer and winter yield financial advantages to both cooling in summer and heating in winter – and CO2 saving advantages in all seasons as well.
Installation of Ground Source Cooling System
To get the full benefit of a ground source cooling installation you will need to employ someone with design and installation experience of ground source cooling systems. A ground source cooling system may not perform well unless it is incorporated into a good design by someone who understands the needs of the building, the use to which the building is being put and the local geology.
For more information on installation of ground source heating and cooling from an experienced source please contact one of our members.
Integration of Renewable Heating and Renewable Cooling
The advantages of integrating renewable heating and renewable cooling and exploiting Seasonal Thermal Energy Storage are explored at Ground Source Heating and Cooling.