The basic technology for heat pumps has been around probably 50 years, its only with the coming of the micro processors and advances in refrigerant gasses and compressor technology that we are where we are today.
The Japanese were at the forefront of developing the technology for the simple reason that most apartments and small houses in Japan have a very small electrical supply compared to say, the UK, Europe and North America.
The race to develop energy efficient appliances such as fridges, freezers, air conditioners and TVs was not driven initially by a green agenda but one of expediency. Having a 15amp rather than an 100amp supply to your accommodation was the driver.
Happily over the last 20 years the technological advances in materials, chemistry and microchips have resulted in the super-efficient products we see today on the market – just at a time where energy efficiency is more important than ever from both an economic and environmental standpoint.
How does air to air heating and cooling work? Where does the heat come from?
Put very simply, if you put your hand on the back of your domestic refrigerator, you will feel heat (of course inside it will be cold). This is brought about by a simple pump, pumping around a refrigerant, which is expanding and contracting in an ever-lasting cycle. The heat from your food in your fridge causes the gas to boil in the heat exchanger inside your fridge – causing ice. The pump then compresses that gas, which causes heat (think of holding your finger on the end of a bicycle pump and pumping – it gets hot). That hot gas, along with the heat from your food, is then sent to the heat exchanger on the outside of your fridge where it gives up its heat to the atmosphere and the process begins again.
A modern day heat pump essentially still uses those basic rules of 50 or more years ago but in a much more sophisticated way. Today’s heat pumps are capable of operating without loss of performance down to outdoor temperatures of -15ºC or more and summer time temperatures of 45ºC when in cooling mode. Fortunately for us, we live in a very temperate geographical location in the UK – although it might not feel like that sometimes!
We are not Scandinavia or Russia, where they can see -30-40ºC in winter and we are not in Dubai where summer time temperatures can be 50ºC. Being surrounded by sea, the UK is in the sweet spot for heat pumps.
Heat pumps are 300-400% efficient – what does this mean?
People say this is not physically possible! If it sounds too good to be true, it most probably is. The best gas boilers these days are around 97% efficient; meaning for 1kw of gas burnt, you get 970W of heat out – a loss of 30W, which is very good for a gas boiler. Heat pumps use a very different technology – using the expansion and contraction of gasses within a ‘sealed system’ which require no topping up as nothing is being consumed. When compared to a gas boiler, for every 1kW of energy you put in a typical typical heat pump system you get 4kW out – an increase of up to 400%.