Heat Pumps

Heat Pumps utilises energy from natural resources such as the ground, air and water. It does not diminish any of these natural resources or produce waste by-products and is therefore deemed a renewable product.

809e841b-9616-4c07-8a86-26865202fb4fThis energy from Mother Nature is transformed by electricity to generate up to 4 times its power output. For every 1kw of electricity provided up to 4kw’s are “free”. No other heat source can provide such impressive efficiencies. The key characteristic of heat pumps over traditional boilers is that the amount of energy produced is greater than the energy used to drive the process.

The heat pump works in the same principle as a refrigerator with the exception that the heat generated is utilised. Refrigerators take heat from the food and release into the room through the back of the unit. In the same way a heat pump obtains heat from the air, earth or water and “pumps up” to a temperature level required to heat a house. A heat pump is at its most efficient when the energy derived from Mother Nature is at its highest and the flow temperature leaving the heat pumps is at its lowest e.g. 35 -40ºC. The preferred heat medium is underfloor heating although high efficiency aluminium radiators and fan coil convector’s can be used for the bedrooms.

How do heat pumps work?

A heat pump only needs a heat source (the ground, air or water), two heat exchangers (one to absorb and another one to release heat) and a relatively small amount of drive energy to keep the system going. The pump extracts the energy at a certain temperature, increases that temperature and then releases it into a medium which is the water running to your low temperature radiators, under floor heating system or fan coil units. Between those two media the heat is moved by means of a working fluid.

Compressor – the essence of heat pumps

As the working fluid passes through the evaporator and extracts heat from the energy source it turns into a gas. This is where the compressor comes in. When you compress a gas the temperature rises, (for example if you inflate the tyre of your bicycle, you can feel the air inside warming up through the rubber). Inside your house the second heat exchange takes place when the compressed gas enters the condenser, a surface which is colder than the gas itself. Finally, the gas condenses and releases its heat this heat then warms your house.

It is important to emphasise that the practical benefits of heat pumps can only be realised if the overall system is properly designed, installed and commissioned. Key factors in maintaining efficiency are:

  • Minimising the temperature difference between the source and the sink i.e selecting the warmest possible source and used the lowest heat distribution temperatures
  • Avoiding the over or under sizing of the heat pump package
  • Ensuring an appropriate control strategy and good control for space heating and hot water
  • Ensuring the correct thermal sizing and hydraulic design of the ground loop system
  • Ensuring that economy electrical tariffs are available

 

We can supply and fit a large range of heat pumps, please contact us for more information