How does a Swimming Pool Heat Pump Work?

Heat pumps work on the opposite principle of air conditioning units. It extracts heat from the surrounding ambient air, allowing it to heat the refrigerant, and then compresses it, making it even hotter. It is then passed through a heat exchanger where the water is heated. The refrigerant is then allowed to expand again, cooling it down and allowing it to absorb heat from the surrounding air again. So only a little electricity is needed to run the fans and compressors, while the heat is provided indirectly by the sun.

A modern pool heat pump is a very efficient water heating device that uses a small amount of electricity to drive the compressor, which is the heart of the heat pump. The thermal energy produced is more than five times the electrical energy used to drive the compressor in standard on/off models, and ten times more for the inverter technology unit. This means that the power consumption of pool heating can be divided by up to 10 compared to normal electrical element heating.

Instead of relying on sunlight or direct radiation, a heat pump extracts thermal energy from the air at any time of the day or night, so it's actually a different form of solar heater. Even in extremely cold conditions (-5°C or less), heat pumps can still provide more than 60% energy savings. In most cases, in South Africa, where our daytime temperatures are relatively warm, the efficiency will be at least 5 times that of an elemental hot water system. A heat pump looks similar to an air conditioner and can be installed either on the floor or on a wall bracket. It's quiet and unobtrusive with a user-friendly controller, has no greenhouse gas emissions, and requires little maintenance.

Heat Pump Cycle

1. One unit of electricity (you pay for it) runs a compressor that draws vaporized freon gas from a liquid-filled evaporator tube. This creates an intense cooling effect (like sweat evaporating from your skin and keeping you cool). The gas absorbs four units of heat from the air flowing outside the evaporator tubes.

2. The compressor squeezes the gas so that its temperature climbs above 200° F (93° C) Result: Five units of heat are added to the gas.

3. High temperature and high pressure gas flows through the inside of the condenser coil. The cooler 80° F (26° C) pool water absorbs five units of heat from the freon, cooling it back to a warm liquid.

4. Warm liquid is forced through a valve. As the pressure drops, it rapidly expands and becomes an extremely cold liquid. This liquid flows back to the evaporator at 1, where the cycle is repeated.

Pool heat pumps are designed for recreational water heating (ground, above-ground or above-ground swimming pools, spas, hot tubs, swim spas, etc.). If you have an air conditioner, dehumidifier, chiller or refrigerator, you already have a heat pump.

All of these devices use the same reliable technology, using electricity and a sealed refrigerant compression system to transfer heat from one place to another. This provides five to seven units of heat to your pool water.