Refrigeration unit cooling capacity and energy consumption relationship and energy saving measures reference

First, the relationship between cold production and energy consumption
The impact of evaporating temperature: as the evaporating temperature decreases, the compressor's compression ratio will increase, leading to an increase in energy consumption per unit of cold production. Specifically, when the evaporation temperature decreases by 1 ℃, the power consumption will increase by 3% -4%. Therefore, in order to save electricity and improve the relative humidity of the cold room, the evaporation temperature difference should be reduced as much as possible and the evaporation temperature should be increased.
The effect of condensing temperature: the rise in condensing temperature will also lead to an increase in the compression ratio of the compressor, thus increasing the energy consumption per unit of cold production. In the condensing temperature range of 25 ℃ -40 ℃, every increase of 1 ℃, power consumption will increase by about 3.2%.
Influence of oil layer on the heat exchange surface: when the heat exchange surface of the condenser and evaporator is covered by oil layer, it will cause the condensing temperature to rise and the evaporating temperature to decrease, which will reduce the cooling capacity and increase the power consumption. For example, if there is 0.1mm thick oil layer on the inner surface of the condenser, it will lead to a decrease of 16.6% in the compressor's cooling capacity and an increase of 12.4% in the power consumption; similarly, if there is 0.1mm thick oil layer on the inner surface of the evaporator, in order to maintain the low temperature requirement, the evaporating temperature will decrease by 2.5℃ and the power consumption will increase by 9.7%.
The impact of air aggregation: air gathered in the condenser will cause condensing pressure increases, which in turn increases power consumption. When the partial pressure of non-condensable gas reaches 1.96×10^5Pa, the compressor power consumption will increase by 18%.
The impact of scale: condenser tube wall if there is a 1.5mm thick scale, will lead to condensing temperature rises 2.8 ℃, power consumption increased by 9.7%.
The effect of frost: evaporator surface if covered with a layer of frost, will reduce its heat transfer coefficient. Especially when the outer surface of the finned tube is frosted, it not only increases the heat transfer thermal resistance, but also makes the air flow between the fins difficult, thus reducing the heat transfer coefficient of the exterior and the heat dissipation area. When the indoor temperature is lower than 0 ℃ and the temperature difference between the two sides of the evaporator tube group is 10 ℃, the evaporator works for one month, and its heat transfer coefficient will be reduced to about 70% before frost.
The influence of superheat: the gas inhaled by the compressor is allowed to have a certain degree of superheat, but when the superheat is too large, the specific volume of the inhaled gas will be increased, resulting in a decrease in the amount of cold production and an increase in power consumption.
Compressor frost treatment: when the compressor comes to frost, if quickly close the suction valve to reduce the amount of cold production, will relatively increase power consumption.

Second, refrigeration operation energy-saving measures
In order to improve the economic efficiency of the refrigeration system, it is necessary to strengthen the operation management of refrigeration equipment, and take effective energy-saving measures.
Strengthen the operation management of equipment: establish the electricity management and unit consumption statistics system to facilitate the assessment of electricity consumption and material consumption quota. At the same time, increase the necessary measuring instruments and apparatus to carry out energy-saving and technological transformation work.
Correctly control and regulate the system liquid supply: avoid the phenomenon of compressor suction over-wetting and overheating, so as to ensure the stable operation of the system and reduce energy consumption.
Reasonable selection of the number of compressor operation: according to the heat load of the system to match the corresponding refrigeration capacity, in order to reduce unnecessary energy consumption.
Adjust the number of fans and pumps running: according to the process requirements and external temperature changes, adjust the number of fans and pumps running to optimize energy consumption.
Regular maintenance of equipment: regular oil, air, defrost and scale removal, in order to maintain good heat transfer equipment, to avoid high condensing pressure and evaporating pressure is too low resulting in increased energy consumption.
Improve water quality: slow down scaling by improving water quality and improve condensing effect of condenser, thus reducing condensing temperature and energy consumption.
Optimize the motor load ratio: when the motor load ratio of the refrigeration equipment is below 0.4, the motor can be changed from △ to Y connection to improve the power factor, and require △ and Y connection can be automatically switched to adapt to different load conditions.
The use of automatic control operation: try to use automatic control operation instead of manual operation, in order to realize the refrigeration system in the best operating conditions. This will not only improve the stability and reliability of the system, but also save electricity.
In summary, by strengthening the operation and management of refrigeration equipment, taking effective energy-saving measures and improving the working conditions of the equipment, the economic efficiency of the refrigeration system can be significantly improved and energy consumption reduced!