1. The main control parameters of screw chillers are refrigeration performance coefficient, rated cooling capacity, input power, and refrigerant type.

2. The selection of chiller units should be considered based on the cooling load and purpose. For refrigeration systems that operate under low load conditions for a long time, it is advisable to use multi head piston compressor units or screw compressor units for easy adjustment and energy saving.

3. When selecting chiller units, priority should be given to units with higher performance coefficient values. According to statistics, the average chiller unit operates throughout the year100%The operating time under load accounts for approximately the total operating time1/4following. Within the total running time100%、75%、50%、25%The operating time ratio of the load is roughly2.3%、41.5%、46.1%、10.1%Therefore, when selecting chillers, priority should be given to models with relatively flat efficiency curves. At the same time, the adjustment range of the load of the chiller unit should be considered when designing and selecting. The multi head screw chiller unit has excellent partial load performance and can be selected according to actual conditions.

4. When selecting a chiller unit, attention should be paid to the nominal operating conditions. The actual cooling capacity of the chiller unit is related to the following factors:

a)Cold water outlet temperature and flow rate;

b)The inlet temperature, flow rate, and fouling coefficient of the cooling water.

5. When selecting a chiller unit, attention should be paid to the normal operating range of the unit, mainly the current limit of the main motor is the current value of the shaft power under nominal operating conditions.

6. Attention should be paid in design selection: under nominal operating flow conditions, the outlet temperature of cold water should not exceed15℃The outdoor dry bulb temperature of the air-cooled unit should not exceed43℃If it is necessary to exceed the above range, it should be understood whether the usage range of the compressor is allowed and whether the power of the main motor is sufficient.

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