08 Dec 2010 04:12:19
Heat pumps explained
Our environment is full of energy, even at sub-zero temperatures there is plenty of energy available.
use conventional refrigeration technology to extract the sun's energy stored in the environment and raise it to a temperature suitable for heating purposes.This principle works even in the middle of winter at temperatures as low as -25°C.
Dimplex heat pumps offer you three different future-proof heat sources: outside air, the ground or water.
heat pumps utilise the outside air as their energy source. Heat pumps can even extract heating energy from the outside air at temperatures as low as -25°C.
heat pumps extract heat from the earth all year round via ground heat collectors buried beneath the ground.
ater to water[/u heat pumps extract thermal energy from underground water. If the supply is readily available and the quality is sufficient, water is the most effective heat source.
A heat pump heating system consists of 3 components: the heat source, the heat pump itself and a heat distribution and storage system.
Heat pumps are able to produce more energy than they consume by using the conventional refrigeration cycle to absorb heat from the environment and raise it to a suitable level for heating.
• 75% of the energy is taken from the environment, i.e. the air or ground and transfered to the heat pump.
• 25% of the energy is sourced from the national grid in the normal way of supplying your electricity. This is used to operate the heat pump but with very low consumption.
• The energy from the air or ground is transfered to the refrigerant inside the heat pumps evaporator. This causes the temperature of the refrigerant to rise and change state from liquid to gas.
• The refrigerant gas is then compressed, using an electrically driven compressor, reducing its volume but causing its temperature to rise significantly.
• A heat exchanger (condenser) then extracts the heat energy from the hot refrigerant to heat water for central heating, underfloor heating or domestic hot water.
• After giving up its heat energy the refrigerant turns back into a liquid and is able to absorb energy from the environment, allowing the cycle to begin again.
Heat pumps are among the most efficient heating and hot water systems available today. Approximately 75% of the energy needed for heating comes from the environment. This means that for every 1kWh of electricity used to power the heat pump compressor, between 3 and 4 kWh of heating energy are produced, giving the heat pump an efficiency of 300-400% or higher.
The heat pump's "efficiency" is known as its "coefficient of performance" (CoP). This is simply a ratio between the proportion of the total energy supplied that can be extracted from the environment and the amount supplied by electricity to run the heat pump compressor. The higher the CoP, the more "free" environmental energy the heat pump is using!