What is the difference between a water source heat pump and an air conditioner?

09-05-2019 MGREENBELT

Under low temperature conditions, the difference in performance degradation between water source heat pumps and air conditioners is not large, but conventional air conditioners are difficult to operate at low temperatures. In environments below -10 ° C, it is generally not recommended to use conventional air conditioning equipment or water source heat pump units.

In winter, the outdoor temperature can reach -30 °C, then the temperature inside the evaporator must be lower than the outdoor temperature. If it is R22 refrigerant, the temperature of the evaporator is generally around -25 °C, and the refrigerant of 410A is generally about -30 °C, so as long as the ambient temperature is higher than -30 °C, external heat will enter the evaporator. If the outdoor temperature reaches -40 ° C, then the heat will go backwards and the evaporator will not absorb the heat. Therefore, the water source heat pump also has a certain working range, and the specific operating temperature range depends on which kind of refrigerant is used.

The compressor end is relatively simple, and the electric energy is forwarded to kinetic energy, and then the kinetic energy is compressed and converted into the internal energy of the refrigerant. The water supply temperature of the water source heat pump is generally between 45 ° C and 60 ° C, while the water supply temperature of the air conditioner is generally 45 ° C. As long as the exhaust temperature of the compressor is higher than the water temperature, the heat source will go from the refrigerant to the water, and then the heat will be brought to the indoor end through the water to achieve the purpose of heating.

Therefore, the performance of the heat pump depends mainly on the following factors: First, the evaporator can not absorb enough heat; Second, the heat dissipation performance of the compressor under low temperature conditions.

At low ambient temperature, the density of the refrigerant will decrease, and the amount of refrigerant entering the compressor will decrease. Then, when the compressor is working, the coil of the motor will heat up, the performance of the cooling motor will also decrease, and the amount of heat dissipation will increase accordingly. Will decrease. At this time, the final exhaust temperature of the condenser will exceed the upper limit. An increase in exhaust temperature is a good thing in itself, because the higher the temperature, the more heat is transferred into the water.

However, after the temperature rises, in addition to the refrigerant, there is another substance in the compressor, the refrigerating oil, which is easily carbonized at high temperatures, and once carbonized, the compressor wears out. Even if the compressor is not worn, the compressor motor burns out. Usually, the compressor burns, and most of it refers to the motor burnout.

Therefore, under the condition of ultra-low temperature, the conventional compressor and cooling method can not meet the requirements of stable operation of the unit. In this case, the water source heat pump is more suitable than the conventional air conditioning unit, so the biggest difference between the water source heat pump and the air conditioner is the difference in the core components.

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