1. How does heat pump work?
A low-pressure liquid refrigerant is vaporized in the heat pump's evaporator and passed into the compressor. As the pressure of the refrigerant increases, so does its temperature. The heated refrigerant runs through a condenser coil within the storage tank, transferring heat to the water stored there. As the refrigerant delivers its heat to the water, it cools and condenses, and then passes through an expansion valve where the pressure is reduced and the cycle starts over. The heat pump only uses a little electricity to produce much heating. As a high COP product, it is much more environment friendly and energy saving than coal and fuel energy rquipment. 

2. How to calculate heat pump heating capacity requirements for swimming pool use?
To calculate required heating capacity for swimming pool constant temperature, we have to calculate three parts. The first is evaporation heat loss of swimming pool water surface, the second is the conduction of heat loss of swimming pool water surface, bottom of pool, pool wall, pipeline and devices, the third is required heat which heats filling water.



 
* The conduction of heat loss Q1 of swimming pool water surface, bottom of pool, pool wall, pipeline and devices The conduction of heat loss Q1 shall be 20% of evaporation heat loss of swimming pool water surface. 
So, required total heating capacity for swimming pool constant temperatureQ=QZ+Q1+Qb.