Water-Cooled Screw Chiller | Primary Centralized Cooling for Cleanrooms and Low-Temperature Cooked Food Plants
I. Working Principle
Screw compressor compresses refrigerant → shell-and-tube water-cooled condenser (cooling water removes heat) → throttling → shell-and-tube evaporator produces chilled water/ethylene glycol low-temperature water; matched with cooling tower + cooling water pump + chilled water pump to form the water system, the condenser dissipates heat via circulating cooling water.
Suitable for centralized cooling of large-area cleanrooms and low-temperature processing rooms, paired with air handling units and ceiling-mounted evaporator units.
II. Operating Water Temperatures and Refrigerants
1. Standard Conditions (Cleanroom HVAC)
Chilled water: 7°C supply / 12°C return; cooling water 32°C in, 37°C out, R134a, R513A environmentally friendly refrigerants.
2. Low-Temperature Conditions (Precision processing below 5°C)
Ethylene glycol solution: -5°C to -10°C supply, use low-temperature screw chiller units.
3. Cooling Capacity Range: 120kW to 3000kW, multiple compressors in modular parallel configuration.
III. Advantages and Disadvantages Compared with Air-Cooled Screw Chillers
Advantages
1. Water-cooled heat dissipation is stable, cooling capacity decay <5% in high summer temperatures, higher overall COP, long-term energy savings of 15%–25%, first choice for large factory areas;
2. Unit installed indoors in a machine room, noise easily isolated, unaffected by outdoor sun exposure, rain, or snow;
3. Lower purchase price per unit of cooling capacity than air-cooled screw chillers.
Disadvantages
1. Must be equipped with: cooling tower, cooling water pump, chilled water pump, expansion tank, water treatment equipment, high initial investment in supporting civil works and auxiliary materials;
2. Consumes tap water for makeup, cooling tower in northern winter requires anti-freeze measures.
IV. Complete Supporting System Composition
1. Main unit: Water-cooled screw chiller (installed in machine room)
2. Cooling water circuit: unit condenser → cooling water pump → outdoor cooling tower
3. Chilled water circuit: unit evaporator → chilled water pump → cleanroom air handling unit / evaporator unit
V. Application Scenarios (Combining Cleanroom + Low-Temperature Workshop + Cold Storage)
1. Class 100,000 clean production area: 7°C chilled water for modular cleanroom air conditioning, temperature control at 22°C, constant temperature and humidity + air purification;
2. Low-temperature clean processing room (0–10°C): low-temperature ethylene glycol chiller unit, connected to indoor evaporator units;
3. Large factory area: water-cooled screw chiller for cleanroom + CO₂/ammonia units dedicated to low-temperature finished product cold storage, separate cooling and heating systems, better energy consumption ratio.
VI. Optional Features
1. Heat recovery water-cooled screw chiller: recovers condenser waste heat, produces 45–60°C hot water for workshop equipment cleaning and heating, extremely high utilization in food plants;
2. PLC intelligent group control: multiple units automatically start/stop based on workshop load, slide valve stepless loading (25%–100% capacity regulation);
3. Explosion-proof model: selected when near hazardous goods warehouses.
VII. Selection Reference
- Workshop area <2000㎡: prioritize air-cooled screw chiller, saving water system investment;
- Workshop >3000㎡, continuous production year-round: prioritize water-cooled screw chiller, operating electricity savings cover initial investment.
