1 the main control parameters of screw chiller are the coefficient of refrigerating performance, the amount of cooling capacity, the input power and the type of refrigerant.
2 screw chiller should be selected according to the cooling load and use. For low load operating conditions for a longer period of refrigeration system, it is appropriate to use multi head piston compressor or screw compressor unit, easy to adjust and energy saving.
3 when the chiller is selected, the unit with higher performance value is preferred. According to the statistics, the annual running time of the general chiller is about 100% of the total running time under the load of 1/4. The total running time of 100%, 75%, 50%, and the load of the running time ratio of roughly 2.3%, 41.5%, 46.1%, 10.1%, 25%. Therefore, in the selection of chillers should give priority to the efficiency curve is relatively flat models. At the same time, should be considered in the design of water chiller load adjustment range. The performance of multi head screw chiller is excellent, and can be selected according to the actual situation.
4 selection of screw chillers, should pay attention to the nominal operating conditions. The actual cooling capacity of screw chillers is related to the following factors:
A. cold water outlet temperature and flow rate;
B. cooling water inlet temperature, flow rate and fouling coefficient.
5 selection of screw chillers, should pay attention to the normal operating range of the type of unit, mainly the current limit of the main motor is the nominal operating conditions of the shaft power current value.
6 in the design selection should pay attention to: in the nominal flow rate, cold water outlet temperature should not exceed 15 degrees, air cooling unit outdoor dry bulb temperature should not exceed 43 degrees C. If it is necessary to exceed the above range, it is necessary to understand whether the use of the compressor is allowed, the power of the main motor is enough.