Calculation Method of Copper Tube Heat Dissipation Area for Closed Circuit Cooling Towers and Q&A
The process of cooling water in a cooling tower is a heat and mass transfer process. The water to be cooled is distributed to the internal packing of the cooling tower using nozzles, water distributors, or distribution pans, which greatly increases the contact area between water and air. Air is circulated by fans, forced airflow, natural wind, or the induced effect of jets.
-
In traditional designs, closed circuit cooling towers intake air from either the lower or upper part of the tower body. This approach has shortcomings such as a small flow area and high flow resistance, which not only affects the heat exchange efficiency but also increases material usage, putting it at a great disadvantage in the current market.
-
Closed Circuit Cooling Tower Condenser: The condenser is the core component of the cooling tower. Its reasonable structural size and layout will directly affect the heat exchange efficiency of the entire cooling tower, thereby affecting the cooling capacity of the entire cooling tower for cooling water. The inclined arrangement of the condenser facilitates draining the water from the condenser in winter to prevent the copper tubes from freezing and cracking.
-
During daily operation, certain technical parameters of the closed circuit cooling tower must be measured to monitor whether its operational level meets the controlled economic indicators. Therefore, the following technical parameters must be monitored on time and recorded in the operation log:
For stainless steel closed circuit cooling towers, because the packing is eliminated, the system resistance of the tower drops to 1/2 of the original. With the same fan, according to the fan characteristic curve, the air volume increases to 1.2 times the original. The air-water ratio also increases to 1.2 times the original, so the cooling temperature difference is 2°C larger than that of packed towers. The packing-free spray cooling tower features uniform spray droplets, no clogging, maintenance-free, stable, and reliable operation. Because the cooling elements of the packing-free cooling tower (high-efficiency low-pressure centrifugal atomization devices) spray water into 0.5mm tiny droplets, their specific surface area is much larger than that of water dispersed into a film by packing, resulting in a large air-water heat transfer surface area and uniform water distribution. This avoids dead zones and channeling caused by packing aging, deformation, and clogging, which lead to uneven cooling point temperature distribution, and the cooling effect is significantly better than that of packed towers.
Question 1: If the return water temperature of the closed circuit cooling tower is 35°C and the outlet water temperature is 20°C, is it necessary to take anti-freezing measures? In addition, how to clean the scale on the copper tubes?
If the return water temperature of the closed circuit cooling tower is 35°C and the outlet water temperature is 20°C, no anti-freezing measures are required, because this temperature will not cause freezing. To clean the scale on the cooling tower copper tubes, organic acids can be used. However, before use, a test must be conducted to see whether a reaction will occur between the two to avoid damaging the copper tubes.
Question 2: What factors are mainly related to the heat transfer coefficient of a closed circuit cooling tower?
The heat transfer coefficient of a closed circuit cooling tower is mainly related to three factors: the convective heat transfer coefficient of the fluid inside the tube, the heat transfer coefficient of the tube wall, and the convective heat transfer coefficient of the external spray water. Moreover, these three are very important parameters and should not be underestimated.
