Heat Pump Case Studies
Heat pumps work by moving energy from one area to another. By accessing energy in the air or ground you can gain a lot of energy for relatively little electricity usage. They can extract energy from the air down to very low temperatures, -20°C for some models.
‘Efficiency’, which isn’t the correct word but is pretty close, can be over 400%, where every 1 unit of electricity gives 4 units of heat into the home. The 3 additional units of heat come from the air or ground which has been cooled down.
As the amount of fossil fuels on our electricity grid reduces our electricity becomes lower carbon, and heat pumps are now significantly lower carbon than other heating systems. they are going to become the normal heating system in UK houses and businesses.
Air Source Heat Pumps work by extracting energy from the air. The external unit looks the same as an industrial refrigeration unit with a large fan, which needs good airflow. By cooling large amounts of air down slightly you can heat the water up water enough to be useful for heating your home and domestic hot water.
Ground source heat pumps have either long ‘slinky’ coils in trenches or a borehole, which is more expensive but more efficient. They are better in cold conditions than Air Source Heat Pumps. Wet ground is better for trenches than dry ground, and in some cases much longer trenches are needed.
Both types work best when supplying warm, rather than hot, water, so underfloor heating or large radiators are used to supply the heat to the rooms. Replacing an existing boiler with a heat pump normally involves replacing the radiators and hot water cylinder too.
Interest free loans are available for both of these technologies and the Renewable Heat Incentive, a small subsidy based on the heat needed, is available until March 2022. this makes them very attractive if your heating system needs upgrading.
There are also Air to Air Heat Pumps available, these have an internal unit similar to an air conditioning system, and can be used for both heating and cooling. These can’t do domestic hot water, and most houses in the UK use wet radiators, so they aren’t as common as in places that need the cooling in the summer.
Modern Heat Pumps are often described as ‘inverter driven’, this means that the power consumption and output can be varied. While older heat pumps would operate at a set level intermittently the new ones vary their output continuously, resulting in more efficient heating.