'Full Design, and Supply of Ground Source Heat Pumps'
For more information or a Free quote call: 01248 671976 or e-mail us on
post@energy-efficiency-centre.com
With a ground source heat pump on average you could save from £300 to £1000 on your heating bills and 2 to 7.5 tonnes of carbon dioxide per year, depending on which fuel is replaced.
Advantages
The efficiency of a ground source heat pump system is measured by the coefficient of performance (CoP). This is the ratio of units of heat output for each unit of electricity used to drive the compressor and pump for the ground loop. Average CoP over the year, known as seasonal efficiency, is around 3-4 although some systems may produce a greater rate of efficiency. This means that for every unit of electricity used to pump the heat, 3-4 units of heat are produced, making it an efficient way of heating a building.
In the same way that your fridge uses refrigerant to extract heat from the inside, keeping your food cool, a ground source heat pump extracts heat from the ground, and uses it to heat your home.
There are three important elements to a ground source heat pump:
1- The Ground Loop, 2- A Heat Pump, and; 3- the Heat Distribution System,
The ground loop:
The evaporator, (e.g. the squiggly thing in the cold part of your fridge) absorbs the heat using the liquid in the ground loop;
The first part of the system is the ground loop; this is simply lengths of pipe buried in the ground, either in a horizontal trench or vertically in a borehole. The pipe is a closed circuit which is filled with a mixture of water and antifreeze; which is pumped around the pipe absorbing heat from the ground.
The ground loop can be laid:
- Horizontal, for use in trenches
- Spiral, coil or 'slinky', also for use in trenches
- Vertically, for use in boreholes
Bore holing can be expensive, so the horizontal trench is the most common method. By laying the pipe in a spiral fashion as in the picture above of a recent installation near Pwllheli, North Wales, the length of the trench can be greatly reduced in comparison with laying the pipe in a straight length.
A heat pump:
The compressor, (this is what makes the noise in a fridge) moves the refrigerant around the heat pump and compresses the gaseous refrigerant to the temperature needed for the heat distribution circuit.
The Heat Pump unit consists of a compressor and it is this unit in the middle of the system that turns the relatively small increase in temperature of the water coming back from the ground to the unit into the considerable rise in temperature needed for heating and hot water.
Heat distribution system:
The condenser, (the hot part at the back of your fridge) gives up heat to a hot water tank which feeds the distribution system.
This consists of under floor heating or radiators for space heating and in some cases water storage for hot water supply.
Because Underfloor Heating uses warm water instead of hot water; it makes it the perfect heat distribution system for a Ground Source Heat Pump. Typically an Underfloor Heating system circulates water of about 45 degrees C through the system, this temperature is easily attainable for an heat pump. Also the working principles of an UFH system means the Heat Pump doesn’t have to work as hard as with a traditional radiator heating system.
A Heat Pump will work fine with a radiator heating system but the radiator sizes should be increased 30% to compensate for the lower water temperature from a Heat Pump than that from an ordinary boiler.
‘For every unit of electricity used to pump the heat, 3-4 units of heat are produced.'
Energy Efficiency Centre - 01248 671976 - post@energy-efficiency-centre.com