Cooling towers need make-up water to counter, among others, water evaporation. I'm trying to figure out what the difference will be between the evaporation rate in the summer and in the winter.
Water temperature to be cooled: 35 degrees Celsius
Winter period: Wet bulb temperature = 5 degrees Celcius, Relative humidity = 85%
Summer period: Wet bulb temperature = 21 degrees Celcius, Relative humidity = 75%
I was told that because the wet bulb temperature in the summer is higher than in the winter, the water in the summer can be cooled down to ~25 degrees, while in the winter it can go to ~17 degrees (cooling tower is operating at max. capacity, no temperature regulation). Because evaporation rate = flowrate*heat capacity*temperature difference over cooling tower / latent heat of evaporation, the evaporation rate will be higher in the winter (flow rate, heat capacity and latent heat of evaporation stay constant).
On the other side, the rel. humidity in the winter is higher than in the summer, so the air can take up less water in the winter, which would mean less evaporation compared to the summer period, no?
Can somebody help with this problem i'm facing?