The heat pump pool heating system has become the most fashionable in the recent years. The heat pump is effective, economical and respectful time to environment with guaranteed water at 28° C throughout the season at a relatively low cost. The heat pump uses renewable and free energy contained in the environment. When 1 calorie of electricity to operate is used, 5 calories taken in air to heat the pool water.

Operating Principle of a Heat Pump for Pool

The heat pump collects the calories (heat) naturally present in the environment (air, water, soil), converts and delivers them to a higher temperature which then diffuses into the home or in the pool. For example, a refrigerator or air conditioner uses the principle of the heat pump to operate in reverse.

Heat pumps are classified according to the environment from which they derive their energy (air, water or soil) and distribution system (air, water or refrigerant). We talk about the heat pump air-air, air-water, water-water, etc. A heat pump pool is usually air-water type and functions as an air conditioner in reverse, you can heat the pool water 15-28° C passing.

How does the heat pump heat the pool?

To remove heat from the air and transfer it to the pool, a ‘cooling’ (or gas) is used. Said fluid flows in the heat pump in liquid or gaseous state in a closed and sealed circuit. This circuit consists of four essential systems;

  1. Evaporator
  2. Compressor
  3. Condenser
  4. Regulator

The heat pump collects calories through the compressor to achieve a higher temperature. This is done through the refrigerant which has the particularity to change state according to their pressure.

  • The liquid becomes gas when its pressure decreases.
  • The fluid becomes liquid when its pressure increases (the gas condenses).


  • Air heat is transferred to liquid refrigerant.
  • The refrigerant enters the evaporator at low temperature.
  • The heat of the warmer air is captured.
  • Increased fluid temperature becomes vapor (gas)> Evaporation


  • The compressor sucks the fluid as gas and compresses to high pressure and temperature> Compression
  • This compression occurs because it heats the gas and it reaches to a temperature of 90° C.
  • A compressor outlet, the refrigerant is at high pressure and as hot gas.


  • Gas at 90° C enters the condenser, and its role is to remove heat from the gas and passing the water to be heated.
  • The gas then comes into contact with the heat source at 25.
  • The cooled gas transmits a part of its heat to the source; both are about 45° C.
  • Upon cooling the gas to a liquid, condenses> Condensation
  • A condenser outlet, the coolant is in liquid form at room temperature, still at high pressure.


  • The refrigerant now passes through the expander element.
  • The low pressure regulator and the reduced pressure is> Relaxation
  • This pressure drop causes substantial cooling liquid (-20° C).

Evaporator – Back to Square One

  • The very cold liquid comes into contact with the cold source (which is hotter than the liquid).
  • The liquid is then heated to boiling.
  • It is then re-sucked by the compressor.

And so on a new cycle begins.

1 – Gas Heating System

The gas heating system uses the gas burning to heat a heat exchange mechanism with water. It is a suitable type of heating for small or as an auxiliary heating system having up to 150m³ pools.


The gas heating equipment must work together with the filter and the pump and its installation must be done outside of the engine room. It works as follows: The computer has a burner fed with gas. Water circulates through the tubes of the heat exchanger passing over the flames, so it is heated and passed back to the pool.


  • The water can be heated in any weather, just gas as fuel is needed.
  • It is a very secure system, as the device has safety measures if the flame is extinguished, the gas is automatically closed.


  • For this type of heater, it is necessary to install a gas plant and always keep such as shower gas or stove, for example.
  • The coil is short, since it is oxidized, chlorine and fire.
  • The use of fossil fuels to heat the pool water is the form that has a higher cost.
  • This type of heating is recommended for small pools only.

2 – Heat Pump System

A heat pump pool is responsible for the absorption and heat transfer retained in the outside air to the pool water device. It is a type of power heater, however, it does not directly transform electrical energy into heat energy, only electricity is used to remove heat from the environment, and water heating is done by heat exchange.


This type of equipment is structured in a closet and is designed to be installed outdoors. Its capacity is determined according to the dimensions of the pool. Basically it functions as an air conditioner reversed, removing heat from outside air and stepping with a compressor, which rules out the cold air. Heat to a coil through which water passes and is heated is transferred. It is a more suitable type of heater for small pools.


  • The installation of the heat pump is simplest compared to other forms of heating.
  • It is the best choice for heating swimming pools or gyms, schools, clinics or hotels.


  • Heat pumps need maintenance later, generating a high cost, in addition to the price paid for electricity because the electricity is fifty times more expensive than solar energy.
  • When the temperature is below 8°C, this type of heater does not work as the gas used is frozen and it is impossible to compress.

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