The Four Major Parts of Air Energy Heat Pump: Condenser

One of the "four major parts" of air-energy water heaters (air-energy heat pumps) is the condenser.
The role of the condenser is just opposite to that of the evaporator. During the operation of the air energy water heater, the high-pressure and high-temperature refrigerant steam formed by the action of the evaporator and the compressor will release heat in the condenser and be absorbed by the water, realizing the exchange of steam and water. During heat exchange, the temperature of water rises after absorbing heat, and the refrigerant changes from a high-temperature and high-pressure gas state to a high-pressure liquid state in the condenser. This is actually the reason why air can produce hot water.

The quality of the condenser directly affects the heat exchange efficiency of the air-source water heater. There are roughly four types of condensers currently used on the market, including coil type, plate type, sleeve type, and shell and tube type. The coil type is mainly used in household products, either placed in water for heat transfer, or outside the water tank, relying on the inner tank for heat transfer; plate condensers have better heat exchange performance and are flexible to install due to their small size. However, the water quality requirements are high; the water quality requirements of the shell and tube condenser are not as strict as those of the plate heat exchanger. When used, the refrigerant and cooling water can completely realize countercurrent heat exchange, but the metal consumption of the shell and tube condenser is large; the shell and tube condenser The heat exchanger is a high-efficiency heat exchanger, and the requirements for water quality are not as strict as that of the plate heat exchanger. When used, the refrigerant and cooling water completely realize counter-current heat exchange, and the volume is relatively small, which has obvious advantages.

In areas with hard water quality, long-term use of air-energy water heaters can easily cause the condenser to scale and affect the heating effect. Because scale is a carbonate with very low solubility produced by the thermal decomposition of bicarbonate, simple cleaning with water cannot effectively remove it. Chemical descalers are generally used for removal. First, drain the water in the water collection pan and remove the silt and dirt inside; then close the drain valve, inject clean water, turn on the water pump, and let the water circulate. During the circulation process, add an appropriate proportion of descaling agent to the water collection pan. The water added with a descaling agent can slowly dissolve the scale during the circulation process to achieve the purpose of cleaning. It is best to control the cleaning time within 4 hours. After the cleaning work is completed, the waste water must be discharged cleanly, and be sure not to forget to flush the system with clean water. Cleaning the condenser can greatly improve the heat exchange efficiency of the unit, making it easier for the refrigerant to transfer heat to the water.

A refrigerant is an indispensable medium in the process of transferring heat. At present, there are two main refrigerants used in air-source water heaters, one is R22 and the other is R134A. However, when R22 is used in air-energy water heaters, the exhaust temperature will be too high, resulting in poor cooling of the compressor lubricating oil, rapidly accelerating cracking, and shortening the life of the compressor. And because R22 refrigerant has a slightly destructive effect on the atmospheric ozone layer and produces a greenhouse effect, it has been listed as a restricted and banned refrigerant. my country will ban its production and use starting from January 1, 2040. R134A is an environmentally friendly refrigerant with low exhaust temperature, but its boiling point is -26.5 degrees. This will cause the heat pump to have low heating efficiency in winter due to the slow evaporation of the refrigerant, so its promotion and application in the north have been limited. Currently, the more promising refrigerant is R410A, which is a near-azeotropic mixed refrigerant composed of R32 and R125 in a mass percentage of 50:50. The temperature slip does not exceed 0.2 degrees, which facilitates refrigerant charging and equipment replacement, and has good heat transfer performance and fluidity.