How to accurately choose water-cooled and air-cooled chillers?

Performance comparison:
The heat transfer temperature difference of the condenser of the water-cooled unit is generally 4 - 8 °C, while that of the air-cooled unit is generally 8 - 15 °C. Under the same outdoor ambient temperature, the temperature of the cooling circulating water is lower than that of the outdoor air. Therefore, the condensing temperature for the normal operation of the air-cooled unit is much higher than that of the water-cooled unit, resulting in the power consumption of the air-cooled unit being greater than that of the water-cooled unit under the same refrigeration capacity.

Comparison of initial equipment investment:
Since the heat exchange efficiency of water is much greater than that of air, compared with the water-cooled condenser with the same heat exchange capacity, the air-cooled condenser has a larger equipment volume, uses more materials, and has a higher manufacturing cost. Since the nominal power of the air-cooled unit is greater than that of the water-cooled unit, the costs for increasing the power capacity and electrical control equipment are also higher.

Comparison of equipment in the machine room:
The air-cooled chiller is an outdoor machine and can be placed on the roof of a building or on the outdoor ground. Its chilled water circulating pump can also be placed together with the unit without occupying the machine room. For the water-cooled chiller, a machine room should be provided to ensure the normal operation and service life of the equipment, including the chiller, the chilled water circulating pump, and the cooling water circulating pump, and cooling tower equipment should be set up on the roof of the building or on the outdoor ground. It can be seen that when a building cannot provide a machine room, choosing an air-cooled chiller should be a more feasible option.

Comparison of operating costs:
Since the water-cooled unit operates at a lower condensing temperature, it has high refrigeration efficiency and low power consumption during unit operation. Generally speaking, compared with the air-cooled unit with the same refrigeration capacity, the total power consumption (including the cooling pump and the cooling tower fan) of the water-cooled chiller is only 70% of that of the air-cooled unit.

Maintenance comparison:
The shell-and-tube condenser used in the water-cooled unit has a relatively small impact on the heat exchange efficiency within a certain range of dirt accumulation. Therefore, the decline in unit performance due to dirt generation is relatively small, the cleaning cycle is long, and the relative maintenance cost is low. Moreover, the heat exchange efficiency of the finned condenser used in the air-cooled unit is greatly affected by dirt accumulation. A dust filter must be installed in front of the heat dissipation finned tubes, and it needs to be cleaned frequently. Since the air-cooled unit operates under high pressure and is generally installed outdoors with a relatively poor operating environment, it is inferior to the water-cooled unit in terms of maintenance and reliability.