How Swimming Pool Heat Pumps Work

How Swimming Pool Heat Pumps Work

Heat pumps use technology similar to air-conditioning units. They use a fan and compressor to take heat from the surrounding air and transfer it to your pool. This article explains how pool heat pumps work

how heat pumps work - heatpumps4pools

How Pool Heat Pumps Work

The fan blows air out of the unit and in doing so, air is drawn over the evaporator coil (around the outside of the unit on the above diagram)

This then transfers heat from the air to the refrigerant gas inside the refrigerant pipes.

how heat pumps work

The compressor compresses the refrigerant gas which causes it’s temperature to increase considerably

This hot gas is then passed through a heat exchanger which has the pool water flowing around the hot refrigerant gas causing heat to be transferred to the pool water

Titanium Pool Heat Exchanger Tube

The Refrigeration Cycle

For every £1 that you spend on electricity with a heat pump, approximately £5 will go into your pool. The electricity to the heat pump simply powers the fan and compressor. The system takes heat from the surroundng air and transfers it to the pool using the refrigeration cycle.

heat pump refrigeration cycle - heatpumps4pools


At 1 a unit of electrical energy (you pay for) runs the compressor which sucks evaporating freon gas from the liquid filled evaporator tube. This causes a strong cooling effect (just like sweat evaporates from you skin & cools you off). The gas picks up four units of heat (FREE) from the air flowing over the outside of the evaporator tubes.

At 2 the compressor squeezes this gas, causing its temperature to climb above 200° F (93° C) Result: Five units of heat added to the gas.

At 3 the hot,high pressure gas flows through the inside of the condenser coil. The colder 80° F (26° C) pool water picks up the five units of heat from the freon which cools it down back to a warm liquid.

At 4 the warm liquid is forced through a valve. As it drops in pressure, it rapidly expands and becomes extremely cold liquid .This liquid flows back into the evaporator At 1 where it repeats the cycle


The output of all air source heat pumps is dependent on the ambient air temperature.

As the air temperature falls, the heat output from the heat pump will also be reduced.

It is therefore important that the choice and sizing of the heat pump takes into account the lowest air temperature that it will be required to operate in.

Our sizing advice will take into account the output of the heat pump at the lowest air temperature.

Please Contact Us for help and advice on the best model and size of heat pump for your pool.

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