Can the Composite-Flow Dual-Inlet Closed Cooling Tower Truly Achieve Refrigeration?

When high-temperature circulating water (typically 55-65℃) enters the closed heat exchange coil of the cooling tower from the system, the cooling process initiates immediately. At this point, the axial flow fans installed on both sides of the tower start operating, drawing in a large volume of ambient air through the dual-inlet design. Compared with the conventional single-inlet structure, this design increases air flow by over 40%, forming a uniform air layer on the outer surface of the coil.

Heat exchange between air and hot water in the coil follows the counterflow principle: cold water enters from the upper part of the coil, hot water from the lower part, and air flows from bottom to top, achieving optimal countercurrent heat transfer. In this stage, pure air cooling can reduce the water temperature by 5-8℃, making it particularly suitable for spring and autumn environmental conditions. Test data shows that at an ambient temperature of 25℃ and relative humidity of 60%, hot water at 65℃ can be cooled to 57℃ solely through the air-cooled mode.

When the ambient temperature rises or the process requires a lower outlet water temperature, the system automatically activates the spray system. Precisely designed nozzles form a uniform water film on the outer surface of the coil, and the heat exchange process enters the critical evaporative cooling stage.

During the evaporation of spray water on the coil surface, each kilogram of water absorbs approximately 2450kJ of latent heat of vaporization, and this phase change process removes most of the heat from the coil. Meanwhile, the dual-inlet air flow accelerates water film evaporation and promptly carries away the generated water vapor from the heat exchange area. This composite-flow design enables multi-dimensional heat exchange between water and air on the coil surface, improving heat exchange efficiency by over 25% compared with single-direction designs.

When the water temperature needs to be cooled close to the ambient wet-bulb temperature, the system enters the deep cooling stage. At this point, the intelligent control system automatically adjusts the spray water flow and fan speed based on real-time monitored parameters such as the inlet-outlet water temperature difference and ambient temperature-humidity.

In this stage, the advantages of composite flow are fully utilized: the cross-flow section ensures large-flow heat exchange, while the counterflow section achieves a lower outlet water temperature. Through precise control, the system can stabilize the outlet water temperature within ±0.5℃ of the set value, fully meeting the temperature control requirements of precision industrial processes.

The entire cooling process is accurately regulated by the intelligent control system. The system collects 12 sets of operating data per second, including:

Ambient wet-bulb temperature

Inlet-outlet water temperature difference

Spray water flow rate

Fan operating status

Water pump working parameters