Refrigerated display cabinet refrigeration system of the compressor role is to flow from the evaporator of the low pressure refrigerant vapor compression, increase the pressure of steam to the condensing temperature corresponding condensing pressure, thus ensuring refrigerant vapor can be condensed liquid at room temperature. The refrigerant vapor is compressed by the compressor and the temperature is increased. Therefore, the refrigerant in the condenser is in high temperature and high pressure relative to the evaporator.
The General compressor is driven by a motor or the motor to compress steam work, therefore, the role of the compressor is essentially consume external work, forcing refrigerant to absorb heat from the refrigeration space (low-temperature heat source) emissions on the environment (relative cooling space for a high or the high high-temperatureheat source). This is consistent with the second law of thermodynamics.
The condenser function of refrigeration display cabinet is to reduce the refrigerant vapor from the evaporator to liquid, and let the gaseous refrigerant heat and condensate the heat exchanger to the environmental medium. So that the refrigerant can be reused. The refrigerant vapor also keeps the temperature and pressure constant while condensing and condensing in the condenser. The corresponding temperature and pressure are called condensation temperature and condensing pressure, respectively, in tk and pk respectively. The condensation temperature increases with the increase of condensation pressure, and they also have a definite corresponding relationship, which can also be found in the saturated vapor table or enthalpy diagram of refrigerant. The heat from the refrigerant to the cooling medium is called the heat load of the condenser.
The evaporator of a refrigerated display case consists of a set of or several sets of coils. Cryogenic liquid refrigerant flows into the evaporator coil, through the wall to absorb coil surrounding medium (air or water) heat boiling vaporization (often called evaporation in engineering), make the medium temperature around the coil to reduce or maintain low-temperature condition, so as to achieve the purpose of cooling.
It can be seen that evaporators are heat exchangers that exchange heat for low-temperature liquid refrigerants and for dielectric that require refrigeration.
The refrigerant maintains the temperature and pressure when the evaporator tube is boiling and vaporized. The corresponding temperature and pressure are called evaporation temperature and evaporation pressure respectively, respectively t0 and p0. Evaporation temperature increases with the evaporating pressure and rise, they have a definite corresponding relationship, for a given refrigerant, using its saturated vapor enthalpy diagrams, tables, or pressure from should be checked against a known t0 p0, and vice versa.
Evaporation pressure can be controlled or regulated by controlling or regulating evaporation pressure, which is usually very low, so the corresponding evaporation pressure is not high. In contrast to condenser, refrigerant is in low temperature and low pressure in evaporator.
When the refrigerant boils in the evaporator, the heat absorbed from the cooling space medium is the refrigerating capacity of the refrigeration system.