Heating and cooling from the ground
Patrick Sherriff shares his experiences on how ground-source heat pumps provide energy-efficient heating and cooling for buildings.
Renewable energy solutions are playing an increasingly important role in how business and public-sector leaders decide on the most cost-effective and eco-friendly heating and cooling systems for their premises.
Ground-Source Heat Pump (GSHP) systems are at the forefront of the drive to help organisations save thousands of pounds in heating and cooling bills and improving their carbon footprint. Many factors are currently driving up the cost of doing business, but the heating and cooling of buildings should not be one of them.
Heating and cooling buildings is a huge drain on the bottom line of most companies these days, and forecasts indicate the situation may soon get a lot worse. Research shows that up to 40% of company annual energy budgets is currently spent heating and cooling commercial premises using traditional oil or gas systems. Another report says that almost 50% of UK carbon emissions are generated from using energy to heat buildings.
The effects of the economic downturn are already taking their toll on many, and coupled with the likelihood of increasing oil and gas prices, the outlook is looking bleak for many. But others have identified the dangers, acting positively as early as possible by installing GSHP systems — and are now reaping the rewards.
GSHP systems extract the constant warmth in the ground, boost its temperature and use it to heat water for space heating and domestic hot water.
But they can also cool buildings, giving them a major advantage and competitive edge over CHP and biomass. Cooling is achieved by simply reversing the GSHP flow during the summer — extracting heat from the air in buildings and putting it back into the ground.
There are clear advantages of using GSHP systems, not least the fact that they can help reduce building heating and cooling running costs by up to 70% (at today’s energy prices) and CO2 emissions by up to 50%.
Within a few years, systems will pay for themselves, and companies will know exactly what their heating and cooling costs will be for the coming years. By continuing to use gas or oil heating systems, the only certainty is that their heating and cooling costs will continue to rise in the future.
Geothermal International has successfully built GSHP systems throughout the UK for a number of public and private-sector organisations, including police headquarters in Gloucester and North Kent and for the NHS at Kings Mill Hospital in Mansfield. We are also installing this low-carbon system in more than 30 schools, colleges and universities .
One recent project is Lambeth College where environmental credentials have been a major consideration in the redevelopment of its Clapham site.
We have played a key role in the development of the new sixth-form centre — part of a £61 million project funded through the Learning Skills Council — harnessing ground heat to cater for almost all of the building’s thermal needs.
Lambeth’s Clapham site will include 43 new teaching rooms for 1200 students, IT centre, roof garden, library, dance studio and a theatre with three performance spaces.
The closed-loop system uses geothermal piles as a heat exchanger to achieve a 24% renewables contribution that almost entirely meets the building’s thermal needs. It provides all the heating and cooling, with the exception of peak sustained cooling when a dry- air cooler is used as a back-up.
Lambeth has been able to add a low-level induction supply ventilation system to help regulate the temperature via variable-air-volume controls as a direct result of using this GSHP system. Three air-handling units in two plant rooms supply air through floor plena in each room. The net result is that air heated by the geothermal piling system can be regulated to each room through floor grilles.
When fewer students are in the room, their body heat draws in warm air through displacement ventilation but it changes into a low-level induction mixing system to provide higher cooling loads when the room is fuller.
This project illustrates the benefits of using a GSHP system as a cost-effective solution to heating and cooling buildings while helping reduce carbon footprint and enhance the green credentials of organisations.
Although we recognise that GSHP technology is not a stand-alone renewable energy solution, it is sustainable and addresses the key issues of fuel supply and security. It is also a flexible and efficient option for heating and cooling new buildings.
Patrick Sherriff is sales and marketing director with Geothermal International
