Page 138 - Industrial Ventilation Design Guidebook

I 00 CHAPTER 4 PHYSICAL FUNDAMENTALS

FIGURE 4.20 Heat transfer according to the parallel flow principle.

The specific heat capacity of humid air calculated per kilogram of dry air is

(b) The same cooling tower is to function as a water cooler. Let the out-
door air be 24 °C, <p = 50%, and the air flow 100 kg/s (dry air). The water in-
let temperature is 24 °C and the water flow 30 kg/s. What is the cooling
capacity if we assume that a ~ Jvj and Ap ~ m v, or aAp = & /t^m,, and also
that the active cooling process is parallel-flow heat transfer?
For case (a) was 44 kg/s and the air flow velocity = (75.5/1.0)/31 = 2.44 m/s.
Therefore the heating capacity (or cooling capacity, depending on the sign) can be
presented as

and solving factor k out of this equation,