How to choose between air cooling, water cooling, and evaporative cooling?

Previously, someone asked which is better for air cooling, water cooling, or evaporative cooling. Today, we will discuss it together and make the following discussion based on practical experience. (Considering that there are too many air-cooled condensers in large refrigeration units, it is usually difficult to arrange them. On the other hand, small water-cooled refrigeration units are also not conducive to use. Therefore, a comparison is made between medium air-cooled units and the same water-cooled refrigeration units.)

1、 System structure:

The air-cooled unit adopts air cooling method (fan cooling); The water-cooled unit adopts a cooling water cooling method, and the water pump, cooling tower, and circulation pipeline circulate and cool the unit. Therefore, the air-cooled unit only requires an air-cooled condenser or fan. The water-cooled chiller unit needs to be equipped with a cooling tower, water pump, and circulating pipeline. Structurally, water cooling is more complex than air cooling.

2、 Applicable scope:

Air cooled refrigeration units are suitable for areas with limited water resources in their location; It is more advantageous to use air-cooled refrigeration units for refrigeration systems with longer annual operating hours; The annual comprehensive cost of air-cooled refrigeration units is lower than that of water-cooled systems, but if the water-cooled system is managed properly and the water replenishment is controlled below 3%, the annual cost of water-cooled units will be lower than that of air-cooled systems.

The air-cooled chiller unit adopts air cooling method, eliminating the essential cooling tower, cooling water pump, and pipeline system of the cooling water system, avoiding condenser scaling and water pipe blockage in areas with poor water quality, and saving water resources. It is currently the most economical and simple model for maintenance and repair among refrigeration equipment products.

3、 From the perspective of cooling capacity:

For example, the 20HP Bizer medium and high temperature compressor 4NCS20.2 has a cooling capacity of 38.6KW and a power of 13.65KW when the evaporation temperature is 0 degrees and the condensation temperature is 50 degrees. However, under the same working conditions, the cooling capacity of water cooling is 44.5KW and the power is 12.1KW. In terms of cooling capacity and electricity consumption, it is slightly better than air-cooled units. But the power of the cooling tower fan for the water cooling pump has not yet been included in the calculation.



Disadvantages of water cooling system: For open cooling circulating water systems, due to the absorption of heat by the cooling water, it comes into contact with the air, causing CO2 to escape into the air, increasing dissolved oxygen and turbidity in the water, resulting in four major problems in the cooling circulating water system: corrosion, scaling, bacterial and algal growth, and sludge. If water quality is not treated, it will seriously damage refrigeration equipment, significantly reduce heat exchange efficiency, and cause energy waste. Therefore, it is very important to treat the system water with corrosion inhibition, scale inhibition, sterilization, and algae elimination.

Disadvantages of air-cooled systems: The power consumption per unit cooling capacity of air-cooled refrigeration units is slightly higher than that of water-cooled units, but the annual comprehensive cost of air-cooled units is basically the same as that of water-cooled units and slightly lower. The results of the technical and economic analysis indicate that it is reasonable to install air-cooled condensers for small and medium-sized refrigeration units. The longer the annual operating time of the refrigeration unit, the more advantageous it is to use air-cooled condensation. This article is from official account of Refrigeration Encyclopedia.

According to the experimental results of research institutions on the economic research of air-cooled, water-cooled, and evaporative condenser systems, it is shown that:

Compared to air-cooled and water-cooled condensers, evaporative condensers save about 1/2 of power consumption, and the circulating water only accounts for 1/8 of water-cooled condensers. Through experimental evaluation, the superiority of water-cooled condensers and evaporative condensers lies in the excellent heat transfer performance of the cooling medium in the condenser. The heat dissipation performance of an evaporative condenser is better than that of a water-cooled condenser. The refrigeration system and cooling capacity of a water-cooled condenser are larger than those of an evaporative condenser, but the cost per unit of cooling capacity of an evaporative condenser is the lowest and the performance is the most superior.



The operation and maintenance of air-cooled condensers are the simplest, and the equipment investment is also minimal, making them suitable for use in areas with limited water resources. Evaporative condensers are more energy-efficient, water-saving, and have superior systems compared to air-cooled and water-cooled condensers. Water cooled condensers are suitable for environments with high condensation loads and temperatures.