Air Source Heat Pumps
Heat Pumps Today
Below is a link to a You Tube video produced by Ron Walker of HVAC Training solutions. It explains in detail, but simply how the refrigeration cycle works. It is this process which is at the heart of all heat pumps.
An air source heat pump works by blowing warm air across a liquid refrigerant, as the refrigerant warms, it expands into a gas; just as the water in your kettle expands in to a gas (steam) when you heat it. This is evaporation and it requires energy.
You can prove the principle to yourself by gently blowing across the back of your hand, it feels warm. Now wet you hand and gently blow across it again, this time it feels cooler, that is because the water is taking the heat energy out of your breath to enable it to evaporate.
As the refrigerant evaporates into a gas, it stores the heat energy it has used to change from a liquid to a gas. By compressing the refrigerant gas it can be changed back into a liquid and it releases the heat energy.
Now what is really great, is that the energy required to compress the refrigerant gas back into a liquid, is a lot less that the energy the refrigerant collects from the air changing from a liquid into a gas. So by running a refrigerant cycle we can collect ‘free’ energy from the air.
A typical heat pump will deliver two to four times as much energy out compared with the energy put in to drive the compressor.