Screw Type Water Chiller Type:
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 water circulation system for heat dissipation, while air-cooled screw chillers utilize finned air heat dissipation.
Key Points for Selection of Screw Chilled Water Units:
The main control parameters of a 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 at low load conditions, it is advisable to choose a multi-head piston compressor unit or a screw compressor unit, which are convenient for adjustment and energy saving.
3. When selecting a chillers unit, prioritize those with higher performance coefficient values. According to data, chillers typically operate at full load for less than 25% of the total running time throughout the year. The proportional running time for 100/75/50/25% loads during the total running time is roughly 2.3%, 41.5%, 46.1%, and 10.1%, respectively. Therefore, it's advisable to opt for chillers with a relatively flat efficiency curve. Additionally, when choosing, consider the adjustable range of the chiller unit's load. Multi-head screw chillers have excellent part-load performance and can be selected based on the actual circumstances.
When selecting a chilled water system, pay attention 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 dirtiness coefficient.
5. When selecting a chillers unit, pay attention to the normal operating range of this model, particularly the main motor's current limit, which is the current value of the shaft power under nominal operating conditions.
6. When selecting design, attention should be paid to: Under nominal operating flow, the outlet temperature of 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 exceed the above range, it is important to understand whether the compressor's operating range allows for it and whether the power of the main motor is sufficient.
