Since 1998, the state has equipped some newly built central grain reserves with grain coolers. Some grain depots have achieved low-temperature green grain storage by using grain coolers, with good results. However, some grain depots have reported that the energy consumption of grain coolers is high, so the utilization rate is not high. How to make good use of grain coolers, improve the utilization rate of grain coolers, and reduce the energy consumption of grain coolers is the key. 1. Select a suitable energy-saving grain cooler (1) Grain coolers with front-mounted fans: Because the outside air passes through the fan before entering the evaporator and is heated by the fan (generally 0.2℃～0.5℃), the load of the refrigeration system is increased, and the energy consumption of the equipment is slightly higher than that of grain coolers with rear-mounted fans. Grain coolers with rear-mounted fans have the advantage of being relatively energy-saving. (2) Variable frequency speed control centrifugal fans are conducive to making full use of economical cooling and ventilation opportunities and reducing the operating load under uneconomical cooling and ventilation conditions. In actual use, it is generally reported that using grain coolers with variable frequency drives saves about 30% of energy. (3) Select grain coolers with high refrigeration performance coefficient and large air volume per unit power. 2. Selecting Cooling Ventilation Under Economic Operating Conditions for Grain Cooling Compressors The most critical factor affecting the economy of grain cooling compressors is the condensing temperature. The condenser of the grain cooling machine's refrigeration system is cooled by ambient air; therefore, the ambient temperature and cooling airflow directly affect the cooling capacity and power consumption of the grain cooling compressor. Selecting cooling ventilation operations under lower ambient temperatures significantly improves the economy of cooling ventilation. 3. Selecting Appropriate Cooling Ventilation Timing and Processes Two key factors affecting the energy consumption of grain cooling ventilation are the temperature difference between the inlet and outlet air and the absolute humidity difference. Reducing the energy consumption of grain cooling ventilation should start from both temperature and absolute humidity aspects. During the refrigeration process, the change in air enthalpy is: ΔI ≈ ρ.Ca.Δt + λ.Δd/1000 ≈ 1.2Δt + 2.5Δd ρ — represents the amount of dry air contained in one cubic meter of moist air, taken as ρ = 1.2 kg dry air/m³. Ca—— represents the specific heat of dry air at constant pressure, 1 kJ/kg.℃ λ—— the latent heat of vaporization of water, taken as 2500 kJ/kg Δt—— represents the temperature change of the inlet and outlet air of the grain cooler, ℃ Δd—— represents the change of the moisture content of the humid air, g/m3 The product of the air volume and the enthalpy difference between the inlet and outlet air is the cooling capacity of the grain cooler. The air enthalpy difference reflects the energy consumption of the grain cooler for cooling each cubic meter of air. Under the condition that the cooling capacity of the grain cooler is constant, the larger the air enthalpy difference, the smaller the air volume of the grain cooler. The inlet air temperature, the relative humidity of the inlet air, and the outlet air temperature have a significant impact on energy consumption, especially the inlet air temperature and the outlet air temperature. (1) Selecting inlet air conditions with lower enthalpy values ​​is the key to reducing cooling ventilation energy consumption. The enthalpy value of air includes not only the air temperature factor but also the absolute humidity factor. Therefore, the timing of cooling ventilation should take into account both the air temperature and humidity conditions. In the absence of wind or with low wind speed, the absolute humidity of the air generally does not change much throughout the day. However, the temperature is high during the day and low at night, so the energy consumption of cooling ventilation is lower at night than during the day. The few hours before sunrise are the time of day when the air enthalpy is the lowest and most favorable for cooling ventilation. When the air temperature passing through the grain layer during cooling ventilation is lower than the outside temperature (and the humidity is generally low), using an insulated return air duct to bring the air with the lower enthalpy back to the air inlet of the grain cooler can achieve a better energy-saving effect. (2) Reasonably increasing the supply air enthalpy and reducing the enthalpy difference between the supply and intake air is another important means of reducing cooling ventilation energy consumption. Reasonably setting the temperature of the cold air coming out of the evaporator of the grain cooler (pre-temperature) and the supply air temperature is conducive to reducing cooling ventilation energy consumption. Gradually reducing the set supply air temperature in stages and appropriately increasing the supply air temperature in the early stage of cooling ventilation can increase the supply air enthalpy, thereby reducing the enthalpy difference between the supply and intake air, increasing the supply air volume per unit power, and reducing energy consumption. At a certain supply air temperature, increasing the supply air humidity, i.e. increasing the front temperature, can reduce the enthalpy difference between the inlet and outlet air, thus reducing energy consumption. Setting the front temperature and supply air temperature of the grain cooler in reasonable segments can not only reduce cooling ventilation energy consumption, but also reduce the loss of grain moisture during cooling ventilation. (3) Use the waste heat of the condenser of the grain cooler as the post-heating heat source for humidity regulation. (4) Cooling and ventilating grains with high moisture content can achieve the dual effect of reducing the moisture content of stored grains and shortening the cooling time, significantly reducing cooling energy consumption. (5) Ventilation method and uniformity of air volume distribution in the grain pile also affect the energy consumption of cooling ventilation. Cross cooling ventilation adopted because the number of coolers is less than the number of ventilation openings will increase energy consumption. If the air volume distribution in the grain pile is more uniform, the unit energy consumption of cooling ventilation will be relatively reduced.