Why do the air source swimming pool heat pump perform not well in winter?
Firstly,we have to the the meaning of COP: COP=Heating capacity / Power consumption.It indicates "how much heat can be 'moved' from the outdoor air into the room by consuming 1 unit of electricity".The theoretical limit for COP is 1 (meaning that 1 unit of electricity can produce a maximum of 1 unit of heat). A heat pump, however, uses electricity to drive a compressor, "extracting" heat energy from the air and transferring it inside. Typically, its COP can reach 2.5-4.5 or even higher (meaning that 1 unit of electricity can "transfer" the equivalent of 2.5-4.5 units of heat).Higher COPs mean greater energy savings: A COP of 3 saves approximately 67% more energy than an electric heater with a COP of 1.
So why do the air source swimming pool heat pump perform not well in winter?
The COP of a heat pump is not a fixed value; it drops sharply as the outdoor temperature decreases, and its heating capacity decreases accordingly. This is due to two interconnected physical principles:
1. Heat Source Degradation (Air Energy Becomes "Rare"):
Heat pumps absorb heat from the outdoor air. The higher the outdoor temperature, the more heat energy (enthalpy) the air contains, and the easier it is to extract. When the outdoor temperature drops to 0°C or even lower, the available heat energy in the air decreases significantly, making it difficult for the heat pump to "absorb" heat, and naturally reducing the amount of heat it can "transfer" per unit time (heating capacity).
2. Lower Evaporation Temperature, Compressor "Works Harder":
Frequent defrosting: In cold and humid weather, the outdoor unit frosts severely. The machine needs to periodically switch from "heating mode" to "cooling mode" to melt the frost. This process not only fails to generate heat but also absorbs heat from the indoor unit.
Like climbing a mountain, the higher the mountain (the greater the temperature difference), the more effort is required to climb (more power consumption), and the slower the climb (less heat output).
The Coefficient of Performance (COP) of a constant-temperature heat pump is the gold standard for measuring its performance, and its reduced heating capacity in winter is determined by the physical nature of the COP.But is not essentially due to a "broken" machine.
