According to analysis, due to insufficient promotion of energy conservation and application of energy-saving technologies, the annual power consumption of refrigeration in my country is still relatively large, about 15 billion kwh, and the energy consumption per unit volume is 30-50 kwh/m3/a. Huge energy consumption is not the point, the point is what channel can effectively reduce the cost of electricity? This is the problem that cold storage practitioners should consider.

 

 

 

 

 

For cold storage, energy consumption is mainly concentrated in the refrigeration system (energy consumption is closely related to the maintenance mechanism of the cold storage and the outdoor temperature difference). Then, in what ways can the cold storage successfully reduce consumption and thus reduce the cost of electricity bills? The suggested reference methods are as follows:

01 Choose high-quality peripheral enclosures - polyurethane thermal insulation board

 

The cold storage has a good enclosure insulation board, and the appropriate thickness is the premise to ensure the low temperature environment in the cold storage. In theory, the thickness of the cold storage insulation board is proportional to the thermal insulation performance of the cold storage, taking into account the economy of the one-time construction cost and the later operation cost. Our Yanghu technology recommends 50mm or 75mm for high temperature storage around 0°C; 100mm for -10°C~-18°C cold storage insulation layer thickness, 120mm or 150mm, -25°C for low temperature cold storage insulation layer thickness above -18°C-25°C The thickness of the insulation layer of the quick-freezing cold storage below ℃ is 200mm. At the same time, the generation of cold bridges and through-wall holes should be avoided to reduce the transfer of heat from outside the storage to the inside of the storage, thereby reducing the cooling load loss of the cold storage envelope.

02 Effectively manage heat exchange equipment

Effective management of heat exchange equipment can also play a role in reducing consumption. Because when the evaporating temperature is -10°C, the power consumption per unit cooling capacity of the compressor decreases by 2.5%-3.2% for every 1°C drop in the condensing temperature; The power is reduced by 3.1%-3.9%. It can be seen that the management of heat exchange equipment is of great significance to reducing consumption and expenses. Measures to reduce energy consumption of heat exchange equipment include:

(1) Regularly drain oil, descale and deflate. The data shows that when there is a 0.1mm thick oil film in the evaporator coil, in order to maintain the set temperature requirements, the power consumption increases by more than 10%; when the scale of the water pipe wall in the condenser reaches 1.5mm, the power consumption An increase of 9.7%; when the refrigeration system is mixed with non-condensable gas, the power consumption will increase by about 18%. It can be seen that it is very necessary to regularly drain oil, descale and deflate the refrigeration system of the cold storage;

(2) Defrost in time. After the surface of the evaporator is frosted, the heat transfer deteriorates, the evaporation temperature drops, and the power consumption increases. Therefore, timely defrosting is also one of the necessary means.

03Improve compressor efficiency

Choose a compressor with a large cooling capacity instead of two compressors with a small cooling capacity; choose a single-machine two-stage machine instead of two combined two-stage machines, etc.

04 Adjust the boot time

On the premise of not affecting the quality of food refrigeration, reduce the running time of the refrigeration compressor during the day and increase the running time of the refrigeration compressor at night, that is, select the low-peak electricity consumption. Not only the cost is reduced, but the condensation temperature is lower at night, which can reduce the power consumption of the compressor.

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05 Make reasonable use of the temperature difference between day and night

In many areas of my country, the temperature difference between day and night is large. Usually, the temperature difference between day and night in oceanic climate areas is 6-10°C, and the temperature difference between day and night in continental climate areas can reach 10-15°C. The ambient temperature at night is low. According to the storage characteristics of the product, the boot time at night can be adjusted and extended. Since the condensing temperature is relatively low, it is beneficial to the energy saving of the cold storage.

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06 Avoid "big horse-drawn carts"

Under different working conditions and load conditions, the compressors, air coolers and other equipment should be reasonably matched to prevent energy loss caused by "big horse-drawn trolleys". Among them, the cooling fan consumes the largest proportion of energy, about 38%-23%. The air volume is proportional to the cooling capacity, and the fan is equipped according to the maximum cooling load. During the initial period of purchase, the cooling capacity is large, and the fans should be fully turned on. However, when the cooling process of the goods is basically completed, the temperature of the warehouse has stabilized, and the number of axial fans should be reduced in time. If it is calculated by opening 2 axial flow fans per warehouse, 40 less axial fans can be opened, a total of 88kW, which consumes more energy than the compressor, and the energy saving can reach 25%. In addition, the multi-open fan is also very easy to generate heat, which increases the cooling energy consumption of the system.

07 Control the appropriate evaporation temperature

When the same cooling capacity is produced, increasing the evaporating temperature can reduce the power consumption of the compressor. Because when the condensing temperature remains unchanged, increasing the evaporating temperature, the suction pressure of the compressor also increases accordingly, the specific volume of the suction steam decreases, the cooling capacity per unit volume increases, the compression ratio decreases, the steam transmission coefficient increases, and the same cooling capacity is produced. Energy consumption is reduced.

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08 Reduce the loss of cold air of the cold storage door

The door of the refrigerator should be closed as soon as it is opened to reduce the load loss of the door opening. For example, if the opening time of the cold storage door is doubled, the cooling loss will increase several times. At the same time, the opening time of the cold storage door is longer, and the high-humidity air outside the storage room will invade, and it is easy to form frost and condensation at the door opening, thereby damaging the storage body structure.

09 Library lighting control
 

According to the design manual of cold storage refrigeration, the warehouse lighting is 1.8-5.8W/㎡, but in actual projects, due to the needs of use, it often exceeds this regulation, and some even reach about 10W/㎡.

10 Use informatization and automatic operation control

When loading, unloading and transporting food, there are often a large number of workers entering the warehouse, which can easily lead to an instantaneous increase in the heat load in the warehouse. The use of automated operation can avoid a large number of workers entering the warehouse at the same time, thereby achieving energy saving effects and reducing labor costs. . In addition, the informatization of cold storage can boost the intelligence and efficiency of cold storage.

11 Loading and unloading with closed platform

The closed low-temperature platform can not only ensure the quality of frozen food to the greatest extent, but also can significantly reduce the heat load entering the refrigerator from the outside, and also reduce the moisture entering the low-temperature space, reduce the frequency of defrosting, and improve the refrigeration. efficiency. However, the cold storage with closed platform will increase its corresponding civil construction costs and increase the difficulty of import and export.

12 Invest in cold storage talents and training efforts

The so-called "three shortages" of the industry, such as "lack of money, lack of people, and lack of business", are obvious. Among them, as the core hub of the supply chain, the problem of "lack of personnel" in cold storage is particularly serious. It is recommended to continue to increase talent investment and training, and improve the professional quality of cold storage practitioners, so as to master the knowledge and skills of cold storage energy saving and consumption reduction, and contribute to promoting the high-quality development of cold storage.