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hat is the reason why the temperature cannot drop when the refrigerator is continuously hot

Update:10-02-2020
Summary:

Due to the particularity of the supermarket freezer, th […]

Due to the particularity of the supermarket freezer, the heat insulation or sealing performance of the freezer itself and the outside world cannot be guaranteed, resulting in large cooling losses! The main reason why the insulation performance of the refrigerator is poor is that the thickness of the insulation layer of the refrigerator pipe and the insulation board that separates the environment from the outside does not reach a certain thickness, and the thickness is not sufficient, which makes the actual insulation and refrigerator required. The effect of thermal insulation is not good. The reason for this is mainly caused by the failure to choose the thickness of the insulation layer of the freezer during the design or the poor quality of the thermal insulation material used during the construction. The heat-insulation and moisture-proof performance of the final insulation material is destroyed, which eventually leads to poor sealing performance. All of these can lead to increased cold losses.
After the frost on the surface of the evaporator is too late or there is too much dust, the heat transfer effect decreases and the slow temperature drop is another important reason. The evaporator has low heat transfer efficiency, which is mainly caused by the thick frost layer on the evaporator surface or excessive dust accumulation. of. Because the surface temperature of the freezer evaporator is mostly lower than 0 ° C and the humidity is relatively high, the moisture in the air is likely to frost and even freeze on the surface of the evaporator, which affects the heat transfer effect of the evaporator. In order to prevent the thick frost layer on the surface of the evaporator, it needs to be defrosted regularly.
There is more air or refrigeration oil in the evaporator, and the heat transfer effect is reduced. Once more refrigerant oil is attached to the inner surface of the evaporator heat transfer tube, the heat transfer coefficient will be reduced. Similarly, if there is more With more air, the heat exchange area of ​​the evaporator is reduced, and its heat transfer efficiency will be significantly reduced, and the temperature drop rate will be slowed down accordingly. Therefore, in the daily operation and maintenance, attention should be paid to timely removing the oil on the inner surface of the evaporator heat transfer tube and exhausting the air in the evaporator to improve the heat transfer efficiency of the evaporator.
不 Throttle valve is improperly adjusted or blocked. If the refrigerant flow is too large or too small, improper adjustment or blockage of the throttle valve will directly affect the refrigerant flow into the evaporator. When the opening degree of the throttle valve is too large, the refrigerant flow rate is too large, the evaporation pressure and evaporation temperature are also increased, and the temperature drop rate will slow down. At the same time, when the opening degree of the throttle valve is too small or blocked, the refrigerant flow rate It also decreases, the cooling capacity of the system also decreases, and the temperature decline rate of the warehouse will also slow down.

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