Screw Type冷水机 Models:
Screw-type chillers can be categorized into water-cooled and air-cooled types based on their cooling methods. Water-cooled chillers use a cooling tower for water circulation and heat dissipation, while air-cooled screw chillers utilize finned air for heat dissipation.
Key Points for Selection of Screw Chiller:
1. The main control parameters of the screw-type chillers include the cooling performance coefficient, rated cooling capacity, input power, and refrigerant type, etc.
2. The selection of a chilled water unit should be based on the cooling load and application. For refrigeration systems with long operating times under low load conditions, it is advisable to choose multi-head piston compressor units or screw compressor units for easier regulation and energy-saving.
3. When selecting a chilled water unit, prioritize those with higher performance coefficient values. According to data, typically, the chilled water units operate at full load for less than 1/4 of their total running time throughout the year. The proportion of running time at 100/75/50/25% loads during the total running time is approximately 2.3%, 41.5%, 46.1%, and 10.1%, respectively. Therefore, it's advisable to choose models with flatter efficiency curves. Additionally, when designing and selecting, consider the load adjustment range of the chilled water unit. Multi-head screw chillers have excellent part-load performance and can be selected based on actual conditions.
4. When selecting a chilled water system, attention should be given to the nominal operating conditions. The actual cooling capacity of the chilled water system is related to the following factors:
a) Cold water outlet temperature and flow rate;
b) Cooling water inlet temperature, flow rate, and dirt factor.
5. When selecting a chilled water unit, pay attention to the normal operating range of the model, particularly the current limit of the main motor, which is the current value of the shaft power under nominal operating conditions.
6. In design selection, attention should be given to: The outlet temperature of cold water under nominal operating flow should not exceed 15°C, and the outdoor dry bulb temperature of the air-cooled unit should not exceed 43°C. If it is necessary to exceed these ranges, it is important to check if the compressor's operating range allows for it and if the main motor's power rating is sufficient.
