Temperature and humidity gradients in a water cooling tower

Cribb quotes values of the ratio ht/hc ranging from 2.4 to 8.5. 

It is seen that the liquid film coefficient is generally considerably higher than the gas film coefficient, but that it is not always safe to ignore the resistance to transfer in the liquid phase. 

Lowe and CHpsTlE Vused a 1.3 m square experimental column fitted with a number of dilTerent types of packing and m ured heat and mass transfer coefficients and pressure drops. They showed that in most cases  

The index rt was found to vary from about 0.4 to 0.8 according to the type of packing. It will be noted that when n % 0.75, there is close agreement with the results given by equation 13.57. 

The heaLtransfer coefficient for the liquid is often large compared with that for the gas phase. As a first approximation, therefore, it can be assumed that die whole of fite resistance to heat transfer lies within the gas phase and that the temperature at the water-air interlace is equal to the temperature of the bulk of the liquid. Thus, everywhere in the tower, Bf = 0i. This simplifies the calculations, since the lines AC, HJ, and so on, have a slope of —00, that is, they become parallel to the enthalpy axis. 

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Temperature and humidity gradients in a water cooling tower... 

Figure 13.18. Temperature and humidity gradients in a water cooling tower (i) upper sections of tower...

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