The difference between water-cooled chillers and air-cooled chillers
With a wide assortment of water-cooled chiller types (scroll, screw, and centrifugal), capacities (16 to 5,500 Tons) and sustainable refrigerant choices, Carrier is a pioneer in the business. Whether it be non-ozone depleting refrigerant, modular or simple setup, superior efficiency and strong controls, these chillers are best for both replacement and new construction projects. Our innovative chiller solutions are designed to bring efficient, dependable cooling to all kinds of large industrial applications.
1. Performance comparison:
The heat transfer temperature difference of the condenser of the water-cooled unit is generally 4~8℃, while the heat transfer temperature difference of the air-cooled unit is generally 8~15℃. Under the same outdoor environment temperature, the water temperature of the cooling circulating water is higher than the outdoor air temperature. Therefore, the condensing temperature of air-cooled units in normal operation is much higher than that of water-cooled units, so that air-cooled units consume more power than water-cooled units under the same cooling capacity.
2. Comparison of initial equipment investment:
Since the heat exchange efficiency of water is far greater than that of air, air-cooled condensers have larger equipment volume, more materials and higher manufacturing costs than water-cooled condensers with the same heat exchange. Even with the addition of the equipment cost of the cooling water system, the total cost of water-cooled chillers is still about 20% lower than that of air-cooled chillers. In addition, because the nominal power of the air-cooled unit is larger than that of the water-cooled unit, the cost of power expansion and electronic control equipment is also higher.
3. Comparison of equipment room:
The air-cooled chiller is an outdoor machine, which can be placed on the roof or outdoor floor of a building, and its chilled water circulation pump can also be placed with the unit without occupying the machine room. For water-cooled chillers, a computer room should be provided to ensure the normal operation and service life of the equipment including chillers, chilled water circulating pumps, and cooling water circulating pumps. At the same time, cooling tower equipment is placed on the building roof or outdoor floor. It can be seen that when the building cannot provide a computer room, it should be a more feasible way to choose an air-cooled chiller.
4. Operation cost comparison:
Since the water-cooled unit operates at a lower condensing temperature, the cooling efficiency is high, and the power consumption of the unit is small. Generally speaking, comparing water-cooled chillers with the same cooling capacity with air-cooled units, the overall power consumption of water-cooled units (including the power consumption of cooling water pumps and cooling tower fans) is only 70% of that of air-cooled units. %.
5. Maintainability comparison:
The shell and tube condenser used in water-cooled units has a certain range of dirt accumulation, which has a small impact on heat exchange efficiency. Therefore, the performance of the unit will decrease with the generation of dirt to a small extent, the cleaning cycle is longer, and the relative maintenance cost will be low . The heat exchange efficiency of the finned condenser used in the air-cooled unit is greatly affected by the accumulation of ash and dirt. A dust filter must be installed in front of the finned tube and frequent cleaning is required. Due to the high operating pressure of air-cooled units, they are generally installed outdoors and the operating environment is relatively harsh. They are not as good as water-cooled chillers in terms of maintainability and reliability.
In summary, although air-cooled units have significant advantages in saving water, simplifying systems, and saving installation space, comprehensive consideration of the entire air-conditioning construction project includes civil construction costs, cooling water and chilled water system costs, and electrical control Compared with water-cooled chillers, air-cooled chillers have no advantages compared with supporting management fees and operating expenses. At present, most air-conditioning projects are mainly equipped with water-cooled chillers.