What should be paid attention to to make the cold storage more energy-saving?
1. The index of reducing the unit heat flow of the cold storage enclosure structure In the design of the cold storage, the unit heat flow q of the outer wall of the low-temperature cold storage generally adopts about 11.63W. If the q can be reduced to 6.9W, for a 5000T~10000T class In low-temperature cold storage, it is estimated that the power cost can be reduced by about 10%. Of course, the reduction of the unit heat flow index means that the heat insulation layer of the envelope structure needs to be thickened, and the one-time investment cost is increased, but compared with the reduction in the regular operating cost of the cold storage, then, whether from an economic perspective or from Considering from the perspective of technical management, it is reasonable and cost-effective to reduce the unit heat flow index of the cold storage enclosure structure.
2. According to different refrigerated foods and different storage periods, determine the corresponding storage temperature value. For various types of foods, especially meat foods during low temperature storage, the biochemical changes and the extent of growth and reproduction inhibition of low temperature bacteria can be determined accordingly. The storage temperature, such as low temperature storage not exceeding half a year, generally used storage temperature is -18--15 ℃; storage for more than half a year, should use low temperature ≤ -18 ℃; for foods with large fat content, such as For the fish with more fat, in order to prevent the oxidation of fat during the low temperature storage period, the storage temperature should be lower than -18℃, and the temperature should be -24 to -20℃.
It can be seen that, after adopting different storage temperatures, for some foods, especially for short-term storage, it is equivalent to raising the evaporating temperature of the refrigeration system, thereby increasing the refrigeration capacity of the refrigeration compressor. In order to achieve energy saving.
3. Reduce the temperature of the refrigerant evaporation temperature and the temperature in the cold storage. When the temperature in the cold storage is constant, as the temperature difference between the evaporation temperature and the temperature in the storage decreases, the evaporation temperature can be increased accordingly. At this time, if the cold storage condensation temperature remains Change means that the refrigeration capacity of the refrigeration compressor is increased. It can also be said that when the same refrigeration capacity is obtained, the consumption of electric energy can be reduced.
According to estimates, when the evaporation temperature decreases by 1℃, it will consume 3-4% more electricity. In addition, reducing the temperature difference value is also extremely beneficial to reduce the dry consumption of food stored in the warehouse. Because the small temperature difference can enable the warehouse to obtain a larger relative humidity, it can slow down the exchange of heat load in the air in the warehouse, so as to reduce the dry consumption of stored food, especially for stored food that has not been packaged. Temperature difference.
4. Two-speed or variable-speed fans are used in the freezing room. In the freezing process of food, the actual release of heat is an uneven heat release process, and the corresponding cold demand for cooling equipment is also uneven. The freezing process of food can be divided into three stages, namely the first stage is the cooling stage, the temperature of the food is reduced from> 0 ℃ to about 0 ~ C; the second stage is the ice crystal formation stage, the food temperature is reduced from about 0 ~ C -5℃ or so; the third stage is freezing and cooling stage, the food is reduced from -5℃ to -15℃ or so.
From the above analysis, it can be seen that in the three stages of food freezing, the second stage requires a large amount of refrigeration. At this time, all the equipment in the freezing room must be put into work, and in the first and last stages, because the heat load per unit time is less, The wind speed of the air cooler can be appropriately reduced, and the air volume can be reduced to achieve the purpose of saving electricity. If the chiller used in the freezing room is only a rotating speed, which cannot be adjusted, it will affect the adjustment of the circulating air volume and indoor blowing speed during the freezing process. Thereby increasing the consumption of electrical energy.
5. Comprehensive use of the cold storage building space, give full play to the multi-functional role. There are peak and low seasons in the freezing room, and the low season is longer than the peak season. In the off-season, it can also be used as a cold room to store packaged food. This not only increases the use efficiency and economic benefits; it alleviates various damages to the enclosure structure, etc., and solves the temperature effect on the adjacent cold storage room; it accelerates the speed of food freezing, shortens the time, and improves the quality of food; it can also cooperate with cold air The use of the machine, the storage of special food requirements of ultra-low temperature environment.