In cooling towersCooling towers air is used to cool water to reduce its temperature so that the water can be reused as cooling water.Fundamentals of psychometric charts and equations to estimate humidity, humid volume and other related properties were presented. Design equations for forced circulation cooling towers with two types of packing were presented. The design methodology was illustrated through examples. Equations to describe constant drying rate and falling drying were discussed. Four types of dryers and their design equations were discussed. Design steps for tray dryer, spray dryer and rotary dryer were given and illustrated through examples.