Principle and Application Description of Evaporative Cooling (Adiabatic Cooling)

Evaporative cooling is a natural and energy-efficient refrigeration technology that achieves air cooling through the evaporative phase change of water, different from the traditional compression air conditioning, which relies on refrigerant circulation for refrigeration. It uses water as the only heat exchange medium and realizes air temperature reduction by utilizing the physical characteristic of water absorbing ambient heat during evaporation. It has multiple functions including cooling, ventilation, air exchange and dust removal, making it an ideal environmentally friendly cooling method for industrial plants, large public places, and open spaces. Evaporative Cooling Pads are widely used in this product as the core heat exchange medium, providing a broad and efficient interface for the full contact between air and water, and are an indispensable part of the evaporative cooling system.

In essence, evaporative cooling is adiabatic cooling, and the core principles of the two are consistent, both following the physical laws of energy conservation and phase change heat absorption — when high-temperature air is in full contact with the surface of a wet medium such as a cooling media, the heat in the air is absorbed by the evaporating water, the sensible heat of the air itself decreases, and the temperature drops rapidly. The entire process does not require refrigeration components such as compressors and refrigerants, and relies on natural physical effects to complete cooling. The wide application of pad filter further improves the cooling efficiency and stability of evaporative cooling.

The use of adiabatic cooling technology can effectively expand the operating range of natural cooling. Specifically, adiabatic cooling refers to evaporating water through fine spray or air scrubbers, and cooling pads are widely used in this process. Due to their characteristics of high heat exchange efficiency, convenient installation, environmental protection, and durability, they have become one of the most commonly used heat exchange carriers in the adiabatic cooling process, together with fine spray and air scrubbers, forming the main implementation methods of adiabatic cooling. Each liter of water evaporated requires about 2500 kilojoules (kJ) of energy, which is directly absorbed from the surrounding air, thereby cooling the air to near its wet bulb temperature. The effect of this cooling method is obviously environment-dependent, and it is most effective under conditions of high dry bulb temperature and low humidity; at the same time, to ensure the comfort of the use environment, corresponding control limits need to be set to avoid air humidity exceeding the recommended environmental range. The reasonable selection and standardized application of wet curtains can also assist in adjusting air humidity and further improve user comfort.

To further improve energy-saving effects, secondary air or water-based heat exchangers can be installed to perform adiabatic cooling on the air discharged from the air-conditioned space. After the discharged air is adiabatically cooled, it can in turn provide more cooling capacity for the introduced fresh air, forming an efficient heat recovery and utilization cycle. Evaporative cooling pads are widely used in this cycle system of the product, and can cooperate with heat exchangers to further enhance the heat exchange and purification effects of fresh air, adsorb dust and impurities in the air, and double the energy-saving and environmental protection benefits. It should be noted that since the adiabatic cooling process occurs on the exhaust air side of the heat exchanger, it will not affect the air state in the air-conditioned space, so the humidity level does not need to be limited, which effectively solves the problem of excessive humidity that may occur in direct adiabatic cooling.

Aolan cooling pad has obvious advantages in many aspects. In terms of material, ultra-fine fibers are used, which have strong water absorption, less debris, and good saturation. In terms of glue, the formula we use is different from that of other suppliers. It does not contain benzene or formaldehyde, so the cooling pad has no peculiar smell and is very environmentally friendly. In terms of the production process, we adopt the whole-piece bonding process. Long-term light can make the filter pad completely dry, avoiding the filter pad being easily damaged due to long-term immersion. At the same time, our products have a higher density. Taking the 5090 model as an example, the number of stacked layers per meter is about 10%-20% more than that of other suppliers. The performance is also more outstanding. At present, the evaporation efficiency on the market is mostly around 75%, while our products can reach more than 82% (100mm thickness). This product is widely used in water-cooled chillers.