Heat pumps offer a form of renewable energy technology readily available in the current market to provide heating and hot water for domestic use. They provide efficient, reliable methods for heating homes and buildings, and help reduce the emission of carbon dioxide and other greenhouse gases due to the low amount electricity consumed.
Heat pumps work by drawing naturally occurring heat from the ground, or the atmosphere, and increasing it via a heat convertor to be used for heating water or air in a domestic system. They do require small amounts of electricity, but the energy that they produce is a bout three of four times the amount used.
Unlike conventional heating systems heat pumps run all of the time. They work at a lower temperature than a normal boiler or radiator heated by burning gas or oil, but due to the fact that they work constantly, they have the same overall effect. Very simply put, rather than allowing a house to cool down when the radiators are turned off, let’s say to a temperature of 10 degrees, and then the radiators have to work harder and at a higher temperature to quickly raise the temperature of the house to the desired 15 degrees. A heat pumps steady supply of heat means that the house temperature never drops to 10 it will always remain at a steady 15.
For a ground source heat pump installers fill a long loop of pipe with water and anti-freeze and bury it under ground. The liquid mixture in the pipe then absorbs heat from the ground, usually between eight and twelve degrees Celsius all year round. The warmed liquid then passes through a heat pump which extracts the heat from the liquid before it returns in the loop back underground. The heat pump uses electricity to increase the temperature and heat water in a tank.
Air source heat pumps differ slightly in as much as they don’t have a loop buried underground, but rather an evaporator coil in a unit attached to the outside of a building which extracts heat from the atmosphere.
Cleantechnica.com listed several advantages and disadvantages of both ground source and air source heat pumps:
Advantages of Ground Source Heat Pumps
• Since they do not have fans, they are quieter.
• The cost to run them is lower.
• It is usually easier to find a location for them because they are smaller.
• Their coefficient of performance is higher and constant.
Advantages of Air Source Heat Pumps
• Installation costs are lower.
• They can be located inside or outside the building.
• They do not need boreholes.
• Higher air temperatures gives them good coefficient of performance.
• Retrofitting is easier.
Disadvantages of Ground Source Heat Pumps
• Installation costs are higher.
• Installing boreholes can create disruptions.
• The horizontal ground loop requires a large area.
• It is essential to size the ground collector accurately due to the difficulty of redoing it.
Disadvantages of Air Source Heat Pumps
• They are noisier than ground source models.
• Their coefficient of performance is generally lower.
• They are larger.
• Your contractor can analyse your location and requirements to give you valuable assistance in choosing the best heat pump for your specific situation.
By. Joao Peixe of Oilprice.com
Joao is a writer for Oilprice.com