 | | Geo-thermal, ground source collector | A geothermal heat pump works by extracting heat energy from a low temperature source and upgrading it to a higher temperature so that it can be used for space and water heating. The temperature of our soil is remarkably stable in the upper 10 feet of the earth’s surface usually between 8-12oC and this represents a renewable resource.
Geothermal heat pumps can tap into this resource for heating and hot water by moving heat from the outside via pipes buried in the shallow ground near the building to the heat pump, this energy is then transferred to a buffer cylinder and used for heating and hot water.
In addition ground source heat pumps can also be installed to harvest heat energy from nearby ponds, streams and wells.
The big difference between using a ground source heat pump to heat your home rather than a gas, oil or coal burner is that, rather than burning and converting stored chemical energy into heat energy, you are simply moving existing heat energy from your surroundings, increasing it and then using it. This means that you will no longer need to spend money on fossil fuels, reducing your heating costs.
The heat pump does require electricity to run, but for every one unit of electricity used to run a typical heat pump, 3 to 5 units of heat are produced making it efficient to a level of 400% compared with only 80% of a good oil burner. This is especially significant given that 80% of Irelands energy consumption is used for heat production.
Ground source heat pumps also use 25-50% less electricity than a conventional heating/cooling system. Their low running costs and efficiency can result in heating bills being reduced by as much as 70%, and also, crucially, reduce the environmental impact considerably. Indeed, if you choose to power your GHP from green electricity then the energy that you use will be 100% renewable, with absolutely no CO2 emissions. | |
| Types of collector |  | | Geo-thermal, vertical boreholes | Ground source collector
If a large enough land area is available, horizontal ground collectors provide an effective method of extracting heat from the ground. The pipework is buried at a depth of approximately 1.25m and spaced 0.75m apart. The land area required is dependent on both the capacity of the heat pump and heat conductance of the soil type in which the pipes are buried.
Vertical boreholes
If land space is limited the ground collectors can be installed vertically in a borehole, drilled up to 100m deep in the ground. Multiple boreholes are commonly used in large installations where very high levels of heat extraction are required. | |
