Heat pumps work by moving heat from one place to another using energy to perform this task. They are used for heating indoor buildings, but they also have outdoors applications such as warming up swimming pools. These devices work well at temperatures above 45 - 50 F, which are the usual temperatures for outside pools .They are usually more expensive than gas pool heaters, but they are also more efficient so that real savings on utility costs can be made. Furthermore, heat pumps usually have a much longer lifespan than gas pool heaters, hence this is a very convenient investment.
How Do Heat Pumps for Pools Work?
The system is quite simple and it consists of five main elements: a blower, ducts that bring water in and out of the system, a compressor, a condenser and an evaporator coil.
The picture below shows the depicts the system.
Water goes through the pump and it passes through a filter and the heat pump heater.
The heat pump heater sources air from outside through a fan and it blows it to the evaporator coil.
The refrigerant in the evaporator coil extracts heat from the air and transforms it into gas.
The gas goes through the compressor that raises the temperature
The very hot gas goes through the condenser that moves the heat from the gas to the cold water that flows into the heater and then in the pool. The hot gas in the condenser turns back into liquid and goes back to the evaporator to restart the cycle.
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What To Consider When Choosing A Heat Pump for Your Swimming Pool?
As the image below shows, there are different factors that affect the optimal size for heat pump heaters for pools. As a result, pools located in areas with wind speeds faster than average, lower levels of humidity, and cool nights need a larger heater.
There are 5 Steps to Calculate Approximately Heater Size:
Determine the desired swimming pool temperature
Determine the average temperature in the coldest month of use
Desired pool temperature - average temperature for coldest month = temperature rise
Calculate pool surface area in square feet.
Determine the amount of energy per output needed for the heater.
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The device efficiency is measured through the Coefficient of Performance (COP) that ranges from 3 to 7 that are equivalent to 300% and 700% performance. This means that for every unit of electricity to run the compressor, you produce 3 or 7 units of heat (depending on COP value) from the heat pump.The higher the COP value, the more efficient the device will be. However, there is no standard test for measuring COP, as you can only compare different models if you know that the manufacturers´ tests have been performed under the same conditions.This is not always the case. The usual conditions for the test imply a temperature of 80 F for the outside air and 80 F for the pool.
The price include the cost of installing the heat pump, but also the cost of the electricity needed to run the appliance and the maintenance costs.