WHAT ARE HEAT PUMPS? HOW DO THEY WORK? WHY SHOULD I BUY ONE?

  • There is a lot of talk- about heat pumps and how they can be used for heating and cooling houses, apartments and buildings - and for use to power industry. In talking with people, there also seem to be a lot of people who don’t really understand what they are or how they work.
  • Probably the best known example of a heat pump is a reverse-cycle air conditioner – one that is able to heat as well as cool.
  • Simply put, a heat pump transfers heat. For heating, it takes heat from the outside air and heats it further to the temperature desired by using electric energy. It also works in the opposite direction, taking warm inside air to the outside to cool.
  • More specifically, a heat pump uses a compressor, a heat exchanger, that can both heat and cool the air it extracts.
  • The heat exchanger either takes heat from an outside heat source and raises its temperature [for heating] or from inside a building and reduces its temperature through a refrigeration cycle [for cooling].
  • The heat source could be outside air, geothermal [like the steam/mud pools [e.g. New Zealand] or waste heat from industries/factories.
  • There is now a great deal of work invested in designing and building industrial heat pumps to replace the use of fossil fuels in industries like steel- and aluminium-production that up till now have used a great deal of fossil fuel and have been major emitters.

 

What are the advantages of a heat pump?

  • EFFICIENCY – heat pumps have much greater efficiency in heating and cooling than other heating and cooling devices because:

                   +  the output from a heat pump is up to four times the amount of  

                       electricity necessary to run it. So it uses less energy to operate it. 

                   +most of the heat is transferred- it is not using large amounts of energy to

                     raise or lower the temperature of the air.

                   +reverse cycle also means you don’t require two devices, one  for heating  

                      and another for cooling: just one appliance does both!

                   + you can create and control heating and cooling zones without

                      having to move appliances from one space to another: different parts of

                      a house/apartment/building can be heated or cooled at any time -again  

                      saving the amount of energy being used.

  • HEALTH/WELLNESS – much healthier than gas because there is no escaping of methane as the gas burns – particularly if the gas heater does not have a chimney/outside outlet – or from leaking gas.
  • SAFETY – entirely safe because it does not use anything that can be knocked over or is able to ignite clothing or any material causing burns or a fire: the actual machinery doing the transfer of heat is generally outside the building.
  • ENVIRONMENT FRIENDLY – if the electricity used to power the heat pump comes from renewable sources [solar, wind, hydro] no fossil fuels are required. The most efficient, cheapest and effective power source for a heat pump is from solar energy generated on a roof or in a solar farm and used on-site or from battery storage.
  • ENVIRONMENT CREATED – is very quiet [in most cases the noise of the compressor is outside the house/building] and peaceful – the quiet hum of the heat pump does not have the noise or the air disturbance of a whirling set of fan blades or water cooler!

 

 

What are the disadvantages?

  • INITIAL COST of the heat pump and its installation is probably the most prohibitive factor. But over time it is an investment that has much value for all the reasons above.
  • Cost also depends on the system for distribution of heating/cooling [wall mounted outlets or ducted].
  • POWER OUTAGES – if frequent! Pair with roof solar and this disadvantage is overcome!

 

[David Smith for ‘Electrifying Bradfield’ – a long time heat pump user!]