The cold storage is constructed in this way, and it saves nearly half of the electricity bill!

The cold storage is constructed in this way, and it saves nearly half of the electricity bill!

Compared with ordinary refrigerators, cold storage has a larger cooling area, and because of the large cooling area, the power consumption is relatively large. Today, the editor of okmarts.com introduces how to make cold storage more energy-efficient. Learning these skills can reduce operating costs and save energy.

　　 1. Reduce the heat load of cold storage

　　1. Enclosure structure of cold storage

The temperature of the low-temperature cold storage is generally around -25℃, while the outdoor daytime temperature in summer is generally above 30℃. That is to say, the temperature difference between the two sides of the cold storage will be about 60℃, plus the daytime temperature. The radiant heat of the sun makes the heat load from the wall and ceiling to the library considerable, and it is an important part of the heat load in the entire library. Enhancing the thermal insulation performance of the enclosure structure is mainly through thickening the thermal insulation layer, applying high-quality thermal insulation layer, and applying reasonable design schemes.

　　 2. Insulation layer thickness

　　 Of course, to thicken the insulation layer of the envelope structure, the one-time investment cost will increase, but compared with the reduction of the cold storage regular operating cost, it is more reasonable whether it is considered from an economic perspective or a technical management perspective.

　　3. There are two commonly used methods to reduce the heat absorption of the outer surface

　　 First, the outer surface of the wall should be white or light-colored to enhance the reflection ability. In the strong sunlight in summer, the temperature of the white surface is 25℃ to 30℃ lower than that of the black surface;

　　 The second is to do sun-shading enclosures or ventilated interlayers on the external wall surface. This method is more complicated in construction and less applied in practice. The method is to set the outer protective structure at a distance between the insulating walls to form an interlayer, and set up vents above and below the interlayer to form natural ventilation, so that the solar radiation heat absorbed by the outer protective can be taken away.

　　4. Cold storage door

　　As the cold storage often requires personnel to enter and exit, loading and unloading goods, the warehouse door needs to be opened and closed frequently. If heat insulation is not done at the door of the warehouse, a certain heat load will also be generated due to the infiltration of high-temperature air outside the warehouse and the heat of personnel. Therefore, the design of cold storage doors is also meaningful.

　　 5. Build a closed platform

Use air cooler to cool down, the temperature can reach 1℃~10℃, and is equipped with sliding refrigerated door, soft sealing joint, refrigerated truck can directly lean on the platform, carry out door-to-door loading and unloading, work, and make in and out of the warehouse Basically not affected by external temperature. Small cold storage can build a door bucket at the entrance.

　　6. ​​Electric refrigerating door (additional cold air curtain)

　　In the early days, the speed of single leaf was 0.3~0.6m/s. At present, the opening speed of high-speed electric refrigerating door reached 1m/s, and the opening speed of double leaf refrigerating door reached 2m/s. To avoid danger, the closing speed is controlled at about half of the opening speed. Sensor type automatic switch is installed in front of the door. These devices are designed to shorten the time of opening and closing doors, improve the efficiency of loading and unloading, and reduce the stay time of operators.

　　7. Interior lighting

　　 Use high-efficiency lamps with low heat, low power and high brightness, such as sodium lamps. The efficiency of high-pressure sodium lamps is 10 times that of ordinary incandescent lamps, and the energy consumption is only 1/10 of that of low-efficiency lamps. At present, new LEDs are used as lighting in some of the more advanced cold storages, which generate less heat and energy consumption.

　　 2. Improve the efficiency of the refrigeration system

　　 1. Use a compressor with economizer

　　 Screw compressors can be steplessly adjusted in the 20~100% energy range to suit changes in load. According to estimates, a screw-type unit with economizer with a cooling capacity of 233kW can save 100,000 kWh of electricity a year by operating 4000 hours a year.

　　 2. Heat exchange equipment

　　The direct evaporative condenser is preferred to replace the water-cooled shell and tube condenser, which not only saves the power consumption of the water pump, but also saves the investment in the cooling tower and the pool. In addition, the direct evaporative condenser requires only 1/10 of the water flow rate of the water-cooled type, which can save a lot of water resources.

　　3. The evaporator end in the cold storage preferentially selects the air cooler instead of the evaporating pipe, which not only saves materials and has a higher heat exchange efficiency, but also if a stepless speed control air cooler is used, the air volume can be changed to adapt to the change of the load in the storage. The goods can run at full speed when they are in the warehouse, and the temperature of the goods can be quickly reduced; when the goods reach the predetermined temperature, the speed is reduced, which avoids the power consumption and machine loss caused by frequent start and stop.

　　 4. Impurities in heat exchange equipment

　　Air separator: When non-condensable gas exists in the refrigeration system, the exhaust temperature will increase due to the increase in condensation pressure. The data shows that when the partial pressure of the refrigeration system reaches 0.2MPa when air is mixed, the power consumption of the system will increase by 18% and the refrigeration capacity will decrease by 8%.

　　Oil separator: The oil film on the inner wall of the evaporator will greatly affect the heat exchange efficiency of the evaporator. When there is a 0.1mm thick oil film in the evaporator tube, in order to maintain the set temperature requirement, the evaporating temperature will drop by 2.5°C and the power consumption will increase by 11%.

　　 5. Removal of scale in the condenser

　　 The thermal resistance of scale is higher than the tube wall of the heat exchanger, which will affect the heat transfer efficiency and increase the condensation pressure. When the water pipe wall in the condenser is scaled by 1.5mm, the condensing temperature will increase by 2.8℃ than the original temperature, and the power consumption will increase by 9.7%. In addition, scale will increase the flow resistance of the cooling water and increase the energy consumption of the water pump.

　　The method of preventing and removing scale can use electronic magnetic water device for descaling, chemical pickling descaling, mechanical descaling, etc.

　　 3. Defrosting of evaporation equipment

　　 When the thickness of the frost layer is> 10 mm, the heat transfer efficiency drops by more than 30%. It can be seen that the frost layer has such a great influence on the heat transfer. It is determined that when the temperature difference between the inside and outside of the tube wall is 10℃, the storage temperature is -18℃, and the heat transfer coefficient K value is only about 70% of the original value after working for one month, especially the ribs in the air cooler. When the sheet tube is frosted, not only the thermal resistance increases, but also the air flow resistance increases. In severe cases, it will be sent out without wind.

　　 It is preferred to use hot gas defrost instead of electric heating to reduce power consumption. The exhaust heat of the compressor can be used as a defrost heat source. The temperature of the frost return water is generally 7~10℃ lower than the condenser inlet water temperature. After treatment, it can be used as condenser cooling water to reduce the condensation temperature.

　　 Four, evaporation temperature adjustment

The reduction of the temperature difference between the evaporating temperature and the temperature in the warehouse can increase the evaporating temperature accordingly. At this time, if the condensing temperature remains the same, it means that the refrigeration compressor cooling capacity has increased. It can also be said that the same cooling capacity is obtained. In this case, the power consumption can be reduced. According to estimates, when the evaporation temperature drops by 1℃, it will consume 2~3% more electricity. In addition, reducing the temperature difference is also extremely beneficial to reducing the dry consumption of food stored in the warehouse.

　　 5. Other energy-saving ways

On the one hand, night-time electricity consumption can save electricity bills due to the "valley period" of night-time electricity consumption. On the other hand, it can balance the power of the power plant generator sets so that there will be no large power fluctuations throughout the day. In a macroscopic sense, It also saves energy. So it should be strongly advocated. Especially in cold storage, quick freezing and ice making are of high value.

　　In addition, ice storage technology can be used. The ice produced at night produces part of the cold during the day, which can bear part of the load to a certain extent, reducing the power required by the system.

　　Automatic control of other equipment:

　　The use of electronic expansion valve can save energy by 10%;

　　 On-demand defrost function, which can save energy by 5%;

　　The room temperature setting that is reset at night can save energy by 4%;

　　 Cooler fan operation control, which can save energy by 3%;

　　The anti-condensation control of cold storage door can save energy by 2%;

　　 Compressor unit and condensing fan control can save energy by 10%