Air source heat pump heating capacity and COP always very important relevant to the environmental temperature, the lower ambient temperature, the lower corresponding COP data. If you feel your air source heat pump not heating in Winter, here you might find the reason:
Take an exmple, an air source heat pump when the ambient temperature 20 ℃, it has 19kW heating capacity (hot water and cold water temperature difference of 40 degrees), the same model heat pump when at ambient temperature 5 ℃, the heating capacity will drop to 11.23kW (hot water and cold water temperature difference of 51 degrees), lower 1/3 of which data than the value of 20 ℃; when at ambient temperature -5 ℃, the heating capacity drop to 5.75kW (hot water and cold water temperature difference of 51 degrees), lower 2/3 of which data than the value of 20 ℃.
According to the relevant data, even if take use of optimization motor performance curve, enhanced vapor injection technology, inverter technology and other means to improve the compressor, air source heat pump units in winter low temperature heating capacity and COP has a big difference compared with standard test condition.
In addition, the lower ambient temperature, the lower tap water temperature, while the winter hot water use volume much higher than the other three seasons. If design and choose the model to meet the hot water load, air source heat pump system work 24 hours satisfy winter extreme conditions -5 ℃, then in the spring and autumn heat pump unit working hours will often less than 6 hours, So how can we better handle this contradiction? Perhaps from the engineering design ideas to find answers.
There are two methods of centralized hot water design:
one is the winter limit load method, requiring the design of the hot water system to ensure the extreme weather conditions in winter hot water load needs.
The other is the winter average load method, requiring the design of the hot water system to ensure that the average temperature in winter under the conditions of the hot water load needs, cannot guarantee hot water load in the low temperature climate, the hot water system by other methods demand. Obviously, under normal circumstances, the winter limit load method design method will need bigger model heat pump than the winter average load method, cost is higher, but energy-saving effect will be better.
No matter how the design, it need heat source heating supply to ensure the hot water demand.