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October 21,2022

Cold storage_ Introduction to energy conservation of controlled atmosphere storage

Cold storage_ The energy consumption factors of air-conditioned storage mainly include cold storage_ Refrigeration system performance, refrigerant selection, compressor condenser and evaporator selection, cold storage_ Scale and plane layout of air-conditioned storage, cold storage_ Type and thickness of thermal insulation layer of air-conditioned storage, cold storage_ Frequency of goods in and out of the air-conditioned warehouse, cold storage_ The heat insulation performance of the external door of the air-conditioned warehouse should be improved_ All factors should be taken into account for the refrigeration efficiency of the air-conditioned storage.

Energy saving cold storage_ The ways to reduce energy consumption of air-conditioned storage are generally divided into two parts: 1) reduce cold storage_ Cooling load of air-conditioned storage, (2) cold storage_ Equipment selection of the controlled atmosphere warehouse.

1、 Fruit and vegetable cold storage_ Energy saving of controlled atmosphere storage

Micro cold storage for fruits and vegetables_ Air conditioned storage refers to the cold storage composed of_ The plates, refrigeration units, evaporators, etc. of the air-conditioned warehouse are pre manufactured in the factory and installed at the production site of agricultural products_ Air conditioning warehouse or civil cold storage_ Air conditioning warehouse or semi assembly and semi civil cold storage_ A cold storage with a storage capacity of less than 200m3 for fresh storage_ Controlled atmosphere warehouse. Classified according to the design temperature, the mini cold storage for fruit thinning_ The air-conditioned storage belongs to the high temperature cold storage_ Controlled atmosphere warehouse. Mini cold storage_ The air-conditioned warehouse is composed of refrigeration system, warehouse, control system, etc.

Yingxiao Fruit and Vegetable Cold Storage_ Factors of energy consumption of air-conditioned storage and cold storage_ Energy saving measures for CA storage:

1. Cold storage_ Enclosure structure of CA storage

Cold storage_ The cooling capacity of the air-conditioned warehouse through the enclosure is in direct proportion to the unit heat flow of the enclosure. Therefore, more efforts should be made to reduce cold storage_ Work hard on the unit heat flow index of the cold storage envelope of the CA storage. To reduce the unit heat flow of the enclosure structure, first, the thermal conductivity of the insulation material should be small, and second, the enclosure structure layer should be thick. However, the thickness should not be too thick, otherwise it will increase the construction cost and waste space. Therefore, thermal insulation materials shall be selected within the appropriate thickness range. In general, thermal insulation materials are required to have low thermal conductivity, low water absorption, good low-temperature resistance and high cost.

Common cold storage_ The thermal insulation materials of CA storage include rice husk, polystyrene foam, polyurethane rigid foam, etc. Rice husk is easy to get materials, but its thermal resistance is small, it is easy to absorb moisture, and the amount is large. The construction of the warehouse body is time-consuming, and the cost conversion is not less than polystyrene; There are many manufacturers of polystyrene foam plastics, which are convenient to purchase, large thermal resistance, moderate price, and convenient to build and install; Polyurethane rigid foam plastic has the largest thermal resistance and the best thermal insulation performance, but its price is high.

2. Cold storage_ Moistureproof and vapor proof the of the enclosure structure of the controlled atmosphere storage

Cold storage_ It is also necessary to take moisture-proof and vapor proof measures for the enclosure structure of the air-conditioned storage, otherwise the thermal insulation performance of the thermal insulation materials will become worse. This is the cold storage_ The thermal insulation performance of the air-conditioned warehouse is good at the beginning of use, but after a period of time, the thermal insulation effect becomes worse. As the water vapor permeates from the high temperature side to the low temperature side, the moisture-proof and vapor barrier should be set at the side with high temperature of the thermal insulation layer.

3. Cold storage_ Evaporation pressure and temperature of controlled atmosphere storage

The evaporation temperature corresponds to the evaporation pressure. When the evaporation pressure is known, the evaporation temperature can be obtained by looking up the table. In cold storage_ When the temperature of the air-conditioned warehouse is fixed, the temperature difference (the difference between the evaporation temperature and the warehouse temperature) will be reduced, and the evaporation temperature can be increased accordingly_ The refrigeration capacity of the air-conditioned refrigerator will be improved, that is, the cycle efficiency will be improved, and the electric energy will be saved accordingly.

4. Cold storage_ Defrosting operation of CA storage

Generally speaking, when the frost layer on the surface of the evaporator has no significant resistance to the air, and the influence of the frost layer is not serious before the flow of air through the evaporator is reduced, it is unnecessary to defrost; When the air flow is significantly reduced, defrosting shall be carried out. The higher the air humidity, evaporator temperature and cold storage_ The greater the temperature difference of the controlled atmosphere warehouse, the easier it is to frost on the evaporator. Combining with the fresh-keeping process, packaging refrigeration can reduce the dry consumption of fruits and vegetables, reduce the number of defrosting times of the evaporator, and actually play a cold storage_ The function of energy conservation of CA storage.

5. Cold storage_ Storage temperature and cold storage of air-conditioned warehouse_ Utilization rate of controlled atmosphere warehouse

Different fruits and vegetables have different storage temperatures, and each kind of fruit and vegetable also has a temperature range suitable for its storage. Energy saving cold storage without affecting the quality of fruits and vegetables_ The higher storage temperature shall be selected for the controlled atmosphere warehouse. Cold storage_ When the temperature of the air-conditioned warehouse is high, the evaporation temperature of the refrigeration system is also increased accordingly, so the refrigeration capacity of the refrigerator will be improved, and the cycle efficiency will certainly be improved. Improve cold storage_ More importantly, the temperature of the controlled atmosphere storage can also reduce the heat transfer through the storage body.

Energy saving cold storage_ The utilization ratio of the controlled atmosphere warehouse is the ratio of the actual volume of fruits and vegetables to the effective volume of the warehouse. For mini cold storage_ The volume utilization ratio of the controlled atmosphere storage is generally not less than 0.3, and certainly not too high, otherwise it will be difficult to cool down. When the volume of fruits and vegetables to be stored changes greatly, it should be separated into two or more cold storages_ Refrigeration room of controlled atmosphere warehouse. In addition, reasonable storage period should be selected_ The energy saving of CA storage is self-evident.

2、 Frequency conversion speed regulation technology used in cold storage_ Energy saving of controlled atmosphere storage

In view of the cold storage_ The refrigeration system accounts for 80% of the power consumption of the air-conditioned storage refrigeration enterprise, and the compressor in the refrigeration system accounts for about 60% of the power consumption, so the energy saving significance of the motor matched with the compressor is more significant.

Cold storage_ During the design of air-conditioned warehouses, the allocation of machines is generally determined according to the maximum mechanical load conditions throughout the year to meet the requirements of peak heat load. However, in actual operation, due to the existence of cold food processing and other changes, the selected cold storage is often designed_ The full load operation time of the compressor in the air-conditioned warehouse is short, and the low load operation time is long, so that the compressor operates under the working condition of less than the design load most of the time. In China, there are generally cold storages_ The motor load of the compressor in the air conditioning silo is low.

3、 Miniature energy-saving cold storage_ Controlled atmosphere storage

Miniature energy-saving cold storage_ The controlled atmosphere warehouse is a storage facility with simple operation, reliable performance and good effect, which is developed according to the main operation and management mode of agricultural production and the economic and technological level of rural households in China. It has won the national patent and the special gold medal of the 8th China Patent New Technology and New Product Expo. It can be widely used in the storage and pre cooling of fruits, vegetables, grains, flowers and other agricultural and sideline products, as well as medicinal materials, food, fine chemical raw materials. It is suitable for the use of urban and rural families and collectives in the north and south of China. It is an important carrier to regulate the light and peak seasons of fruits and vegetables and change the local resource advantages into the economy.

Refrigeration equipment is a miniature energy-saving cold storage_ The most critical part of the modified atmosphere warehouse is designed and manufactured by the National Agricultural Products Freshness Preservation Engineering Technology Research Center (Tianjin) Green Star Freshness Equipment Co., Ltd. Green Star Company mainly develops and produces supporting refrigeration equipment and quick freezing refrigerators suitable for rural families, wholesale markets and supermarkets_ Air conditioning warehouse equipment and assembled cold storage_ Air conditioned warehouse, and undertake various micro cold storages_ Air conditioned storage, large and medium-sized cold storage_ Air conditioned storage, air conditioned cold storage_ Air conditioning silo project.

Miniature energy-saving cold storage_ The main features of the controlled atmosphere warehouse equipment:

(1) Miniature energy-saving cold storage_ Refrigerant filling and commissioning of the air-conditioned storage are completed by strict inspection before leaving the factory. At the same time, the installation is convenient and fast. Just connect the indoor unit and the outdoor unit with pipes and connect the power supply.

(2) Miniature energy-saving cold storage_ The refrigeration unit of the air-conditioned warehouse adopts the imported fully enclosed refrigeration compressor, and the main control components can also be foreign products, so the operation is safe and reliable, and the trouble free operation time is long.

(3) Miniature energy-saving cold storage_ The automatic control system of the air-conditioned warehouse adopts microcomputer control, which is accurate in temperature control and simple in operation. The unit has automatic and manual dual operation functions. It is equipped with a variety of automatic protection devices and an electronic temperature display to facilitate users to observe the cold storage_ Temperature in the controlled atmosphere warehouse.

(4) Miniature energy-saving cold storage_ The unit of the air-conditioned warehouse adopts hot gas or electric defrosting mode, with short defrosting time and small temperature fluctuation in the warehouse during defrosting.

Miniature energy-saving cold storage_ The most commonly used specifications of air-conditioned storage are 90m3 and 120m3, and the building investment is generally 15~20000 yuan_ Key points in the design of air-conditioned warehouse The warehouse built has fast cooling speed, good thermal insulation performance, and cold storage_ The temperature fluctuation of the air-conditioned warehouse is small, and the empty warehouse is generally started within 48 hours_ The temperature of the controlled atmosphere warehouse can be reduced from 20 ℃ to 0 ℃; The daily power consumption of the equipment is generally 40~50 ℃ in the pre cooling and cooling stages of the fruit_ The daily power consumption of the air-conditioned warehouse is only 7~8 ℃ after the temperature is stable. In the north, natural cold source ventilation can be used to cool down in winter, and the monthly power consumption is very low.

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