Cooling tower capacity

This problem needs to be looked at the other way round.

First, determine the process heat loads that are wanted to be cooled.

Second, determine the maximum air temperatures and humidities to be experienced locally.

Third, contact a number of suppliers that will recommend various sizes of towers that will achieve the cooling rate required. From that, the sizing information will be determined. Management of operation of a cooling tower is tricky to the uninitiated, and suppliers will give good advice.

Remember that the lowest temperature achievable in a cooling tower is the wet-bulb temperature of the air passing through it at any moment, as cooling is effected by evaporation; at 100% relative humidity, the wet-bulb temperature, no further cooling by evaporation is possible. To go to a lower utility temperature, an additional process step is required, and that is called refrigeration.

Got eat Crabtree goffer eat.

<Burp> 27 degrees centigrade? Pull the other one! The water temperature will be the same as the wet-bulb temperature of the air going though. <Belch>

27 degrees. That'ud be a good ol' box to live in. <Hrrrrph. Cough, splutter>

Cooling towers are sized, using the following:

1) Capacity is stated in tons of refrigeration.

2) For mechanical refrigeration, circulation rate of the water is 3 gpm/ton. For absorption refrigeration, circulation rate is 4 gpm/ton.

(If it is process cooling, then you must determine the circulation rate required.)

3) Tower ratings are based on: a)design wet bulb temperature - highest expected ambient wet bulb temperature; b) temperature range of water - temperature of water entering the tower (hot side) minus temperature of water leaving the tower (cold side); and c) approach temperature - cold water temperature minus wet bulb temperature.

(Sensible temperature has very little effect on cooling tower performance)

Example of typical HVAC cooling tower design: 100 ton refrigeration load, circulating 300 gpm; wet bulb temperature (at design) 78 dF; temperature range = 95 dF entering water - 85 dF leaving water =10 deg; approach temperature = 85 dF leaving water temperature - 78 dF wet bulb = 7 deg. From a practical standpoint you do not try to lower the cold water temperature to equal wet bulb temperature. Practical approach would be 6 - 8 deg.

So, with the above numbers, you would size the tower as follows: 100 ton capacity, circulating 300 gpm; at 78 dF design wb; 10 deg range, and 7 deg approach.

I would suggest that you contact Marley Cooling Tower Co.

g scott

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When I ponder, I sits and thinks, sometimes I just sits.