In the process of air conditioning heating, the condenser is used as the indoor unit and the evaporator as the outdoor unit. Today we will focus on the working principle of the evaporator in the air conditioning system.
No matter the air conditioning is "cooling" or "heating", it exchanges heat with the outside through various forms of refrigerant in the pipeline, transfers the "cooling capacity" or "heat" of the refrigerant to the outside, and then takes this part of heat away through the fresh air system to achieve the effect of cooling and heating.
The evaporator is a kind of equipment for heating refrigerant and absorbing heat to the outside. It mainly consists of a heating chamber and an evaporation chamber. The liquid refrigerant enters through the feeding port. Meanwhile, the heating steam heats the heating tube bundle inside the heating chamber (the smaller pipeline in the figure below). The thicker tube in the middle of the heating chamber has a smaller heating area than the heating tube bundle, so the heating tube bundle vaporizes cold. The medium rises into the evaporation chamber, while the liquid refrigerant in the central circulation tube drops, and the circulation continues. (the cross-sectional area of the central circulation tube is about 40% - 100% of the total cross-sectional area of the heating tube bundle, which also directly affects the efficiency of the evaporator.)
The application of evaporator in fresh air heat exchange unit and fan coil unit is mainly to provide cold water in the refrigeration process and the heated refrigerant in the heating process. Its application in the ground source heat pump system is opposite to that in the condenser. In the heating process of the ground source heat pump unit, the evaporator belongs to the equipment on the ground source side, which heats the circulating water on the ground source side, and then transfers the hot water to the condenser through the heat exchange of the unit. The condenser discharges the heat in the hot water. In the refrigeration process of the unit, the evaporator belongs to the terminal equipment, which is on the ground source side. The condenser on the ground source side condenses the water, and supplies the evaporator with external heat absorption, so as to achieve the effect of external cooling.