Water-cooled scroll chiller

I. Unit Introduction

The water‑cooled scroll chiller adopts hermetic flexible scroll compressors as core components and shell‑and‑tube water‑cooled condensers. It requires supporting cooling towers and cooling water pumps to form a cooling‑water circuit. The main unit is installed inside an equipment room. It produces chilled water for air‑conditioning terminals or process equipment. It is a chiller for small‑to‑medium cooling capacity and supports multi‑unit parallel modular operation.Cooling capacity range: generally ≤ 260 kW, widely used for small‑capacity projects with equipment rooms.

II. System Composition

1. Main Unit (Indoor Equipment Room Installation)

Hermetic Scroll Compressor: Multiple scroll heads connected in parallel (2‑8 units). Independent refrigerant circuits with stepped capacity regulation. Failure of one compressor will not shut down the whole unit. Good liquid‑slugging resistance and low failure rate. Main refrigerants: R22, R410A, R404A.

Shell‑and‑Tube Water‑Cooled Condenser: Rejects refrigerant heat via external cooling water. A cooling tower and cooling‑water pump are mandatory.

Plate / Shell‑and‑Tube Evaporator: Produces chilled water.

Electronic expansion valve, gas‑liquid separator, PLC controller. Multiple protections including water‑flow protection, anti‑freezing, high‑low‑pressure protection, overload protection and phase‑sequence protection.

Note: The unit normally has no built‑in water pump or water tank, which shall be provided externally.

2. Auxiliary External Systems

Cooling water side: cooling tower, cooling‑water pump and cooling‑water piping.‑ Chilled water side: chilled‑water pump, expansion tank, indoor terminals / process equipment.

III. Refrigeration Principle

The scroll compressor compresses refrigerant into high‑temperature, high‑pressure gas.

Inside the shell‑and‑tube condenser, high‑temperature refrigerant transfers heat to cooling water and liquefies; heat is carried to the cooling tower for outdoor heat rejection.

The electronic expansion valve throttles refrigerant for pressure and temperature reduction.

The evaporator absorbs heat from chilled water and delivers low‑temperature chilled water for circulation to terminals.

IV. Advantages

High overall energy efficiency: Water‑side heat transfer is far more efficient than air cooling. COP degradation is minor under high summer ambient temperature; full‑load COP reaches 4.0‑4.8. Suitable for long‑duration continuous operation with lower power cost than air‑cooled scroll chillers.

Low outdoor noise: Main unit is placed indoors without outdoor fan noise, producing little disturbance to surrounding buildings.

Modular expandable: Multiple units can be paralleled for capacity stacking and mutual backup.

Highly universal scroll‑compressor spare parts, easy maintenance and low component cost.

Unit located inside equipment room with stable ambient temperature; freeze‑crack risk for water circuits is much lower than air‑cooled units.

V. Disadvantages

Mandatory equipment room, cooling tower, cooling‑water pump and associated piping, requiring civil‑engineering work; higher initial‑site‑work volume than air‑cooled scroll chillers.

Water consumption exists: Cooling towers produce evaporation loss, limiting application in water‑scarce regions.

Limited single‑unit cooling‑capacity ceiling; less suitable for ultra‑large‑capacity projects compared with screw chillers.

Capacity is adjusted only by compressor on‑off cycling; poorer part‑load energy‑saving performance than variable‑frequency screw or magnetic‑levitation centrifugal chillers.

Outdoor cooling towers require regular maintenance, with risks of water drift, scaling and microbial growth.

VI. Application Scenarios

Small‑and‑medium commercial central air‑conditioning: standalone office buildings, shopping malls, clinics, hotels, hospitals and clubs with available equipment rooms.

Small‑and‑medium‑scale industrial cooling: injection molding, machine‑tool cooling, laboratory constant‑temperature control, small electroplating‑process cooling for long‑time continuous‑operation demands.

Projects with available equipment room and cooling‑tower space, pursuing higher operating efficiency than air‑cooled solutions.

Noise‑sensitive sites where large outdoor air‑cooled units on rooftops are not permitted.

VII. Model‑Selection Reference

Small cooling capacity (≤ 260 kW)

Low‑budget, no cooling‑tower: Air‑cooled scroll (modular chiller)

Equipment room available, high‑efficiency priority: Water‑cooled scroll chiller

VIII. Maintenance Key Points

Regularly clean cooling‑tower fills and condenser tubes; scaling will cause high‑pressure trips and efficiency drop.

Apply water treatment for cooling‑water circuits to prevent scaling and corrosion.

Periodically check compressor operating current, contactors and all protection devices.

Implement anti‑freezing measures for water circuits during winter shutdown; cooling‑tower outdoor piping must be properly freeze‑protected.

Inspect chilled‑water pipe insulation to avoid condensation and dripping.

Selection Tip

Select water‑cooled scroll chiller when equipment room is available, cooling capacity is small‑scale, long‑time operation is required and cooling‑tower installation is permitted.

Precautions for Unit Use

Installation precautions

1. When lifting, positioning, and installing the unit, safety must be taken into account to prevent collisions and ensure the integrity of the equipment.

2. If the unit is installed outdoors, efforts should be made to avoid exposure to wind and rain (except for rainproof types), direct sunlight, or other heat sources that directly radiate; The computer room environment must be kept dry, clean, and ensure good ventilation, leaving space for unit maintenance and upkeep.

3. For air-cooled units, please ensure that there are no obstructions around the unit and reserve 1 meter of space; There is no obstruction within 2 meters of the top of the unit to ensure good ventilation.

4. It is recommended to install the unit on a strong and level ground, and install shock-absorbing rubber pads under the unit chassis to correct the level of the unit. If there are anchor bolts, they must be installed and fixed.

5. The circulating water pump used in conjunction with the unit should be selected and installed according to the data requirements such as water flow rate and water resistance required by the unit.

6. The water pump must be installed in front of the inlet of the unit, and it is recommended to install a filter at the inlet of the water pump to prevent foreign objects from entering the heat exchanger of the unit; If the unit is installed in areas with poor water quality, water treatment must be carried out first to avoid damage to the heat exchanger.  

7. It is recommended to install valves, water pressure gauges, thermometers, water flow switches, and other equipment for the water pipeline system connecting the unit, in order to facilitate the inspection and maintenance of the unit's daily operation.

8. To prevent air from being trapped in the water system, the air must be completely discharged before starting the compressor.

9. The chilled water pipeline must be insulated properly to avoid loss of cooling capacity, condensation, and freezing.

10. The weight of the system connection pipeline shall not be borne by the machine body. Rubber shock-absorbing flexible joints and gate valves shall be installed at the inlet and outlet of the unit to avoid vibration and facilitate maintenance.

11.When configuring wires for the unit, wires with slightly larger cross-sections (with margin) should be selected according to the power consumption, and reliable electronic control components and grounding power sources should be installed to prevent accidents such as overload and leakage.

12. As the unit is equipped with reverse phase and phase loss protection, attention must be paid to whether the line phase is correct during wiring installation. The unit cannot operate normally when the phase is misconnected or missing.    

13. The operator of the unit must observe the operation status of the unit at all times. Once any abnormal situation is found, please promptly troubleshoot. Forced operation will inevitably cause damage to the unit.

Precautions for operation:

1. Before starting up, check whether all water outlets and pipelines of the unit have been correctly installed and connected.

2. Before starting up, check if the power supply of the unit is connected and if the phase sequence is correct.

3. Before starting up, ensure the safety of the power and water sources. Please carefully refer to the equipment operation manual and strictly follow the instructions for use and operation.

Maintenance precautions:

1. Regularly replace the water in the water tank (it is recommended to replace it every 2 months).

2. Regularly clean the radiator of the unit. For air-cooled units, it is recommended to clean the radiator every 3 months; It is recommended to clean the shell and tube condenser and cooling tower of water-cooled units every 6 months (if the usage environment or water quality is poor, it is recommended to shorten the cleaning cycle).

3. If the unit is not used for a long time, please turn off the main power supply; When the ambient temperature is below 0 ℃ and the unit is shut down for more than 6 hours, the unit and pipelines may freeze, and the damage caused by this is not covered by the warranty. 

The best way to avoid pipeline freezing is to completely drain all the water in the unit system!

4. Regularly check the water quality on site to ensure that the water source is qualified (pH ≈ 7). If it contains corrosive substances and causes damage to the unit, it is not covered by the warranty.

5. When the unit encounters unavoidable faults during use, please inform our company of the unit model, component name, and other information so that we can provide you with services more quickly.

6. During the warranty period, our company promises to provide free maintenance services for the unit (excluding human damage, improper use, natural disasters, and uncontrollable factors).

Warning: This unit is a high-voltage, highly specialized mechanical equipment, and should be operated correctly by professional technicians strictly in accordance with the "User and Installation Manual".