Winter temperatures in cold areas of my country are low and the climate is dry. The calculated outdoor temperature for heating is basically -5 to -15°C, and the average outdoor relative humidity in the coldest month is basically between 45% and 65%. If air source heat pumps are used in these areas, the frosting phenomenon will be less serious. Therefore, the frost problem is not the biggest obstacle to the use of air source heat pumps in these areas in winter. However, there are the following problems that restrict the application of air source heat pumps in cold areas.
(1) When the heat required is relatively large, the heating capacity of the air source heat pump is insufficient.
(2) The reliability of air source heat pumps in cold areas is poor.
(3) In low temperature environments, the energy efficiency ratio (EER) of air source heat pumps will drop rapidly.