The section from the compressor outlet through the cond […]
The section from the compressor outlet through the condenser to the expansion valve is called the high pressure side of the refrigerated cold room; the pressure in this section is equal to the saturation pressure of the refrigerant at the condensing temperature. High-pressure side is characterized by: refrigerant to the surrounding environment is condensed into a liquid heat, refrigerant flows out of the condenser, the temperature dropped into supercooled liquid.
The section from the outlet of the expansion valve to the return air into the compressor is referred to as the low pressure side of the refrigeration system and its pressure is the saturation pressure of the evaporation temperature within the evaporator. The low-pressure side of the refrigerant first showed a wet steam state, and the refrigerant gradually changed from wet steam to vapor refrigerant after absorbing heat in the evaporator. At the evaporator exit, the temperature of the refrigerant is returned to the superheated gas state. When the supercooled liquid refrigerant passes through the expansion valve, the pressure is reduced from high pressure to low pressure (but no power is consumed and there is no heat exchange in the outside world) due to the throttling effect. At the same time, a small amount of liquid refrigerant is vaporized and the temperature decreases. Refrigerant into the evaporator after evaporation (vaporization) endothermic. Low temperature and low pressure gas refrigerant is sucked into the compressor, and through the compressor into the next refrigeration cycle.
In the refrigeration cycle, the heat flow per kilogram of refrigerant circulating from the object to be cooled is called the unit weight capacity, expressed in symbol q, in kcal / kg. The unit weight capacity is a special parameter that indicates the effect of the refrigeration cycle. This is determined by the nature of the refrigerant, circulating temperature and other conditions, the lower the evaporation temperature, the higher the condensation temperature, the smaller the value, the greater the contrary. The cooling capacity of the refrigeration unit is the quantity of heat absorbed by the object to be cooled and released in the condenser per unit time, indicated by the symbol Q in kcal / kg. The value of Q is equal to the product of the cold weight flow rate G and the unit weight capacity q, ie, Q = G·q.