1, due to the freezer insulation or sealing performance is poor, resulting in large cold loss
The reason why the poor thermal insulation performance is because the pipeline, insulation board and other insulation layer thickness is not enough, insulation and thermal insulation effect is not good, it is mainly the design of the insulation layer thickness is not selected properly or the construction of the insulation material quality is poor. In addition, in the process of construction, the insulation material insulation moisture resistance may be damaged resulting in insulation layer moisture, deformation, or even rotten, its heat insulation and thermal insulation ability to decline, the cold loss increases, the temperature drop significantly slowed down. Another important reason for the cold loss is the poor sealing performance, there are more hot air from the leakage invasion. Generally, if the sealing strip in the door or cold cabinet heat insulation sealing phenomenon, it shows that the seal is not tight. In addition, frequent opening and closing of the door or more people together into the warehouse, will also increase the cold loss. Should try to avoid opening the door to prevent a lot of hot air into. Of course, into the inventory frequently or too large a quantity of goods, the heat load increases dramatically, to cool down to the required temperature generally takes a long time.
2, the evaporator surface frost is too thick or too much dust, the heat transfer effect decreases leading to a slow decline in temperature is another important reason for the evaporator heat transfer efficiency is low, which is mainly due to the evaporator surface frost layer is too thick or too much dust caused by. Due to the cold cabinet evaporator surface temperature is mostly below 0 ℃, and humidity is relatively high, the moisture in the air is very easy in the evaporator surface frost, or even ice, affecting the heat transfer effect of the evaporator. In order to prevent the evaporator surface frost layer is too thick, it is necessary to defrost it regularly.
Here are two simple defrosting methods:
① stop the machine to melt frost. That is, stop the compressor running, open the door, let the temperature rise, to be automatically melted frost layer, and then restart the compressor. ② Frost. After moving the goods out of the freezer, directly with a higher temperature of tap water to flush the evaporator tube surface, so that the frost layer dissolved or fall off. In addition to the thick frost will lead to the evaporator heat transfer effect is not good, the evaporator surface due to a long period of time without cleaning and dust accumulation is too thick, its heat transfer efficiency will also be significantly reduced.
3, supermarket freezer evaporator in the presence of more air or refrigeration oil, heat transfer effect decreases
Once the evaporator heat transfer tube attached to the inner surface of the more frozen oil, its heat transfer coefficient will be reduced, the same, if there is more air in the heat transfer tube, the evaporator heat transfer area is reduced, the heat transfer efficiency will also be significantly reduced, and the rate of temperature drop is slowed down. Therefore, in the daily operation and maintenance, should pay attention to timely removal of evaporator heat transfer tube surface oil and discharge the air in the evaporator, in order to improve the heat transfer efficiency of the evaporator.
4, throttle valve improperly adjusted or clogged, refrigerant flow is too large or too small
Throttle valve improperly regulated or blocked, will directly affect the refrigerant flow into the evaporator. When the throttle valve is open too large, the refrigerant flow is large, evaporative pressure and evaporative temperature increases, the temperature drop will slow down; at the same time, when the throttle valve is open too small or blocked, the refrigerant flow is also reduced, the system’s refrigeration capacity is also reduced, the temperature of the storage room will slow down the rate of decline. Generally by observing the evaporation pressure, evaporation temperature and suction pipe frost to determine whether the throttle refrigerant flow is appropriate. Throttle blockage is an important factor affecting the refrigerant flow, causing throttle blockage is the main reason for ice plug and dirty plug. Ice plug is due to the drying effect of the dryer is not good, the refrigerant contains water, flow through the throttle valve, the temperature drops to below 0 ℃, the moisture in the refrigerant into ice and block the throttle hole; dirty plug is due to the throttle valve inlet filter mesh on the accumulation of a large number of dirt, refrigerant flow is not smooth, the formation of blockage.
Post time: Sep-23-2024
