Close Cooling Tower Cooling Temperature, Wet Ball Temperature
The closed cooling tower is used as a water -cooled equipment, relying on water evaporation and air to exchange heat, so the lowest cooling temperature will definitely be controlled within a certain range. The heat dissipation principle of the closed cooling tower is mainly through the heat exchange of water and air, and the heat is taken away through the principle of evaporation of water. Therefore, the cooling minimum temperature of the closed cooling tower is the wet ball temperature+3-5 degrees Celsius.
- Assume that it does not affect the conditions:
Suppose that the water of the cubic cubic water is to cool down, the surface of the water surface and the air foundation is affected by unsaturated flowing air. The contact with the water layer is very thin. The changes in the air state during the surface layer, assuming that the radiation temperature changes can be ignored, and there are no other affecting temperature conditions.
- Cold temperature analysis:
Heat dissipation: The temperature of the heating air increases, the volume expansion rises, the cold air is added below, the cold air continues to suck the heat and expand heat circulation, and the heat is continuously taken away.
Principle diagram of flow heat dissipation
Set the device to use the initial water temperature T and air temperature T. The temperature of the T is higher than the temperature T. When the two are in contact, the temperature of T is evaporated and flowing heat dissipation. The water temperature T is the same as the air temperature T.
However, at this time, the heat dissipation stopped, the evaporation and heat dissipation did not stop, and the water vapor in the air did not reach the saturation state. Therefore, the water vapor pressure P2 in the page will be greater than the water vapor pressure P1 in the air. That is, the liquid surface will continue to flow into the air, which is the heat.
The heat from the page continuously accepts water molecular heat from the page, and the temperature will gradually higher than the temperature of the water surface. As the temperature difference is formed, it will generate heat dissipation. Continue cooling depends on the difference in heat consumption of evaporation and the difference in heat absorption of flow heat dissipation. During the evaporation of water, the water temperature gradually spreads, and the formation method becomes slower. When it reaches a certain temperature, it is in a balanced state when the temperature of the wet ball is the same.
In this process, there is a constant existence of a balance of flow heat dissipation and evaporation heat dissipation.
During the evaporation process, the heat was passed to the water, and it was consumed in the evaporation of water. The heat evaporated through the water and returned to the air. In this process, we have paid the heating evaporation process.
- In the actual application of the closed cooling tower, the temperature difference:
During the operation of the closed cooling tower, there is a heat effect. According to the closed cooling tower inside, it can be cooled to the wet ball temperature, but this prerequisite is that it requires unlimited heat exchange time and unlimited closed cooling tower Essence Therefore, in actual use, the minimum temperature of our cooling is 3-5 ° C higher than the temperature of the wet ball.
- Calculate the meteorological conditions of the highest cooling tower water temperature shall meet the requirements:
4.1 According to the production process, the daily average meteorological conditions of 5%-10%are calculated according to the frequency statistical method.
1.2 When the cooling products have industry standards or low standards for cooling water temperature, they can appropriately reduce the meteorological standards according to the specific requirements.
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