Throttling device: the throttling device is mainly used for cooling and depressurization. It can adjust the refrigerant flow to make the liquid flow easier to evaporate under a lower pressure. The evaporation effect directly affects the efficiency of the evaporator to absorb air heat.
At present, the throttling devices used in air source heat pump water heater mainly include capillary, thermal expansion valve and electronic expansion valve. Thermal expansion valve and electronic expansion valve are mainly used in commercial heat pump water heaters
Electronic expansion valve is also a kind of throttling device commonly used at present. Its advantages include:
1. The flow regulation is not affected by the change of condensation pressure;
2. It can compensate for the change of super cooling degree of refrigerant liquid in front of expansion valve;
3. Fast and accurate execution;
4. Effectively control the super heat and maximize the capacity of the evaporator;
Four way valve: the four-way valve is mainly used to change the flow direction of working medium in the system when the main engine needs defrosting, so that the condenser during heating becomes the evaporator, absorbing heat from hot water; while the evaporator during heating becomes the condenser, releasing heat and defrosting. Therefore, the heat pump can not only not heat when defrosting, but also reduce the temperature of hot water in the water tank, double the heat loss. Generally, the heat wasted due to defrosting of the main engine accounts for about 20% of the total heat production. This is also one of the important reasons for the low energy efficiency ratio of air source heat pump in winter.
The four-way valve is not an essential part of the heat pump water heater product. If other defrosting methods are adopted, the four-way valve can be canceled.
Fan and electric control system
Fan: it is used to increase the heat exchange effect between the heat in the air and the evaporator, and ensure that the evaporator is not easy to frost.
Electric control: used to control the normal operation of the whole machine.