Energy optimization

You may need to clarify the question before anyone else can clarify the topic.

1. CWPR could mean several thing involving chilled water, pressure, regulator, return, etc.

2. 35°C is not generally a credible wet-bulb (wb) temperature; even in Dahran the design wb is only about 30°C. If the ambient temperature is 23-25°C, then the wb temperature is even less (or at most equal).

3. On the other hand, if the cooling water is 35°C (without the inappropriate wb designation), ambient temperatures of 23-25°C are suitable for effective cooling.

The key items are the area of heat exchange surface; the thermal conductivity of the separating materials and boundary layers; and the LMTD (logarithmic mean temperature difference) between the two fluids undergoing heat exchange.

In the case of 32°C wb, 45°C entering, and 35°C leaving temperature, the LMTD is (45-35)/ln[(45-32)/(35-32)] ≈ 6.82°C.

In my experience, this is rather low. It is achievable, but it requires a relatively large cooling tower.

To be a bit facetious, the design philosophy of cooling towers is beatnik--keep cool, daddy-o.

Generally you select cooling towers to match the most adverse conditions likely to be encountered. When loads are lighter, or ambient wb cooler, you slow down or shut off fans and/or pumps accordingly.