Selection knowledge of screw chiller

Selection knowledge of screw chiller

Screw chiller is a large-scale industrial refrigeration equipment. It is widely used in central air-conditioning and large-scale refrigeration industry. It plays an important role in refrigeration, cooling and cooling. The working principle of water cycle is adopted to save water resources. Use cold water to directly cool the equipment. The temperature of industrial equipment does not rise. Constant equipment low temperature state.

　　1. The selection of screw chiller should be considered according to the cooling load and where it is going to be used. For refrigeration systems under low-load operating conditions for a long time, it is suitable to choose a multi-head piston compressor unit or a screw compressor unit, which is convenient for conditioning and energy saving, which is what we often call double-head screw chiller, When the load changes, the screw chiller automatically determines the number of start-ups, and the compressor is in the best working condition, thereby effectively saving electric energy.

　　2. When selecting screw chillers, give priority to units with higher coefficient of performance. According to previous statistics, the operating time of a normal screw chiller under 100% load accounts for less than 1/4 of the operating time. The operating time ratios of 100%, 75%, 50%, and 25% load during the sub-operation time are roughly 2.3%, 41.5%, 46.1%, and 10.1%. Therefore, when choosing a chiller, priority should be given to the screw chiller model with a flat efficiency curve. At the same time, the load adjustment range of the chiller should be considered when designing and selecting. The multi-head screw chiller has excellent partial load performance. The screw chiller can be selected according to the actual situation of the factory.

　　 3. When selecting screw chillers, pay attention to the conditions of the nominal working conditions. The actual cooling capacity of the chiller is related to the following two points: a, the temperature and flow of the cold water outlet; b, the inlet temperature, flow and fouling coefficient of the cooling water.

　　4. When selecting screw chillers, you should pay attention to the normal working range of this type of screw chiller. The main reason is that the current limit of the motor is the current value of the shaft power under surface conditions.

　　5. Pay attention to the design and selection of screw chillers: under the nominal working condition flow, the outlet temperature of the cold water should not exceed 15℃, and the outdoor dry bulb temperature of the air-cooled unit should not exceed 43℃. If it is necessary to go beyond the above-mentioned scope, understand whether the compressor is allowed to be used and whether the power of the motor is sufficient.