Heated healthcare

Ground source heat pumps (GSHPs) can be installed in most of the UK and provide a clean way of heating buildings by using solar energy stored in the ground. Pipes are laid in a closed loop through a borehole or in shallow trenches and as water is pumped through these pipes it picks up some of the energy stored in the adjacent ground, gaining a few degrees in temperature. The pipes then pass into a heat exchange unit, which works on a principle similar to a domestic refrigerator, raising the temperature of an internal circuit that is warm enough to provide space heating and, in some systems, domestic hot water.
    
The only energy used by ground source heat pump systems is electricity to power the pumps. Typically, a ground source heat pump will deliver three or four times as much thermal energy (heat) as is used in electrical energy to drive the system.
    
GSHPs are eligible for grants under the new Low Carbon Buildings Programme, and the market for them is expected to quadruple in size over the next 5 years and gain to as much as 10 per cent of the market for heating systems in new homes.

The right solution
Ground source heat pumps are an excellent solution for supplying heating and cooling to new build hospitals, clinics and care centres, since they offer a lower running cost and are a renewable energy solution. In many boroughs where a renewable target is stipulated, ground source heat pumps usually achieve this target with the need for no other renewable technologies. This can offer considerable planning advantages. There are a number of examples of care centres and clinics utilising GSHPs in the UK, and within two years there will be a number of large hospitals utilising GSHPs for their total heating and cooling.

Two types
There are two main types of GSHP systems: the closed loop and the open loop. Almost all ground source heat pumps being installed in the UK are closed loops. This means that the water circulating round the collector loop, picking up heat from the ground as it does so, returns through the heat pump and back into the collector loop.

As the water never comes into contact with the ground itself, it is normal to add some antifreeze, which means that the temperature of the water inside the collector loop can fall below zero. Even at these very low temperatures the water will still collect heat from the surrounding ground that can be extracted by the heat pump and used to heat the building.
    
In some continental countries open loops are used, where the heat pump extracts groundwater and then returns it into the ground after passing through the heat pump. This requires a reliable water table and an extraction licence from the local water supply company.
    
External loops can be laid in almost any type of ground, but will often need to be surrounded by a small amount of sharp sand, or similar, to improve the contact between the pipe and the surrounding ground.

Efficient energy source
GSHPs are the most efficient heating systems available, providing up to four times as much useful heat as the electrical energy used to drive the pumps. Ideally suited to new homes, off the gas-main buildings and businesses, GSHP systems are also responsible for lower emissions of green house gases than oil or LPG central heating. This means that new homes heated from the ground obtain excellent energy ratings on the new A-G scale that will be used in homebuyers packs from June 2007.
    
Ground source heating is by no means a new technology, but a combination of factors including the Government’s microgeneration strategy such as the Low Carbons Building Programme Grant Scheme, increasing fossil fuel costs and a surge in new house builds across the country have helped to cause its recent growth.

Massive growth
The scope for further growth in the UK is massive. As most GSHP systems work best with underfloor heating, which require a lower temperature than conventional radiators, the market expansion is likely to be strongest in the new build sector. A GSHP/underfloor system offers many benefits, such as constant draught-free comfort level, and – especially useful for offices or shops and some hospitals etc – the ability to heat large open plan areas. Ground source heat pumps are also seen as being a convenient way of avoiding the price risks associated with oil or LPG heating for properties off the mains gas network.
    
There is as much opportunity for growth in the housing sector as in the commercial market. Dr Tim Lunel of the National Energy Foundation1 believes that: “demand for ground source heat pumps will continue to surge and one of the key drivers is the ‘Merton Rule’ requiring 10 per cent renewables, which an increasing number of local authorities are adopting. This requires new developments to meet at least 10 per cent of their predicted energy use from renewable sources, and incorporating GSHPs is technically one of the most straightforward ways of doing this”.
    
The GSHP industry will also benefit from the grants for low carbon technologies as most of the funding seems to be aimed at new build projects.
    
GSHPs are already widely used in Northern America and several European Countries including Austria, Germany and Sweden, with over 500,000 units installed worldwide. There are certainly lessons to be learnt in terms of quality standards for product and installation. Historically GSHPs have been difficult to install and much can be learned from overseas.

More information
The Ground Source Heat Pump Association is open to all those interested in the industry2 including potential customers, installers and suppliers of equipment, heating engineers, underfloor heating system suppliers, drillers and consultants. For more information about joining please email theresa.quinn@gshp.org.uk.

Notes
1. The National Energy Foundation (NEF) is an independent educational charity based in Milton Keynes and controlled by an eminent Board of Trustees. Established in 1989 it mobilises individuals, businesses and communities to make their contribution to reducing carbon emissions through energy efficiency and use of sustainable energy sources in order to maintain the affordability of energy and to combat global climate change. The Foundation encourages an integrated approach to the installation of renewable energy with energy efficiency, through public education and information programmes, and provides advice and consultancy to the public and private sectors. The NEF acts as secretariat for the Ground Source Heat Pump Association.

2.# Manufacturers of GSHPs are primarily represented by the Heat Pump Association with which the GSHPA works very closely.

For more information
About joining please email Theresa.quinn@nef.org.uk
Website: www.nef.org.uk