How does a heat pump work? Impress friends with your knowledge.

1. THE APPLIANCE OF SCIENCE.

You might think heat pumps are the latest in modern technology – which to a degree they are. But the first theoretical description of how a heat pump works was written by Lord Kelvin in 1852.  If that name sounds familiar, it’s because units of absolute temperatures are named in kelvin – in his honour.

However, he didn’t make a working heat pump. An Austrian engineer Peter von Rittinger made the first working model in around 1855.

So the technology is more than 150 years old, and it all bases itself on one of the fundamental laws of the universe – the second law of thermodynamics.
The team at Oxygen Air reckon that’s a bit heady and say all it means is that heat always moves to something cooler – like hot food will cool quickly on a cold plate!

A heat pump taps into this thermodynamic law and moves, yes moves, heat from warmer things to cooler things.  

2. IT’S ALL ABOUT THE REFRIGERANT.

To move warmth from area to another, heat pumps use a refrigerant that circulates around the outdoor unit. Because it’s colder than the outdoor air, it warms up and turns into a gas – this is called a state change, a bit like boiling water turning to steam. The gas then goes into the unit’s compressor that compresses the gas – releasing the warmth which then goes into your home. As the gas loses the warmth, it cools down and turns back into a liquid which returns to the outdoor unit where the cycle repeats.

The refrigerant used in most residential heat pumps and air conditioners in New Zealand is R-32 (Difluoromethane) and normally you will see this on a sticker on the side of the outside unit. R-32 is often considered to be the most balanced refrigerant according to the tech team at Oxygen Air as it provides the right mix of environmental impact, energy efficiency, safety and cost-effectiveness.

You might recall years back the drive to remove CFC’s from air conditioners in cars, homes – as well as in aerosol cans. The new replacement gases have far lower Global Warming Potential (GWP) and as such are friendlier to our planet. You might also see R-454B which is mostly used in new HVAC systems or R-290 (propane) which is often used for hot water heat pumps where higher temperatures are required.

3. WHAT DRIVES MY POWER BILL?

Since a heat pump doesn’t actually heat an element, the energy used is for driving the fan and the compressor and those use very little energy. For every unit of energy used, the latest high performance heat pumps can deliver up to five units of energy as warmth or as cool air in summer.

Heat pumps take a little while to get up to speed, but when they reach optimum, they tick away quietly using their smart sensors to maintain the comfort level you’ve chosen.

Best of all, a heat pump improves the quality of the air in your home by eliminating odours, filtering out pollutants and irritants like allergens and dust.
You can even use a heat pump just to dehumidify your home if it’s feeling damp or musty. A great feature if you’ve been away on holiday for a while.

Still wondering how a heat pump works or got questions? Just talk to the team at Oxygen Air, they’re New Zealand’s leading installer of heat pumps and know the ins and outs and the best solution for your home.