Cooling Tower or Chiller?

hi

its a common practice in the manufacturing that PHE is using cooling tower. may i ask if what kind of PHE are you using?, what volume of water, and stages your system has?

anyway from 33 to 25C i think its better for you to use chiller because as far as my experience here in the food processing plant its hard to bring down temperature from 28c using cooling tower.

on the other hand maybe you should consider the re computation of your PHE capacity you can add another set for better performance. the only reason why it doesnt go down to 25 probably because of its rating and the volume that goes through into it.

For a cooling tower, the relevant air-side temperature is the wet-bulb temperature, which is surely less than 50°C (dry-bulb.) Even in Dahran, which is about the worst possible case in the world, the design wet-bulb is "only" 30°C.

On a warm day approaching this temperature, you might just barely be able to cool your cooling water to 33°C, but 25°C will be impossible except on cool days or at night.

Therefore, some sort of refrigeration cycle is indicated. The evaporating temperature should be about 5 to 10°C colder than the water, so let us say 18°C. The condensing temperature should be about 10° above the design wet-bulb, hence 40°C.

This whole process runs at a temperature higher than that of a typical air-conditioning chiller. I don't know yet what the best refrigerant would be, nor what is allowed in your location.

You mention 350 m³/h. What are the input and output temperatures of the cooling water?

That's about as far as I can go right now.

It is never possible to lower the temperature of the cooling water in an evaporative tower below the wet-bulb temperature of the surrounding air. If lower temperatures are required, then a fridge plant to provide a chilled liquid circuit is the only route forward.