Heat Rejection Factors

1. Surface Area (8 to 16 fin/inch)

2. type of material (thermal conductivity)

3. cleanliness of Surface

4. Condensing Medium (temp. diff.)T. D = air SDT – entering air

= water SDT – leaving water

Air Cooled

•  15 to 35 f / TD

•  600 to 1200 CFM @ 1000 FPM

Water Cooled

•  8 to 15 F / TD (water and refrigerant counter flow)

Recirculating – closed cooling tower 3 gals/min/ton

Water Waste Systems – 1.5 gals/min/ton