Problem 12.4: A cooling tower serves a 750ton chiller 750
From Chapter 12 Problem Set. Level 2: Applied Thinking.
Question
A cooling tower serves a 750-ton chiller (750 refrigeration tons). The tower range is 10°F. Using an evaporation factor of 0.85:
- Calculate the cooling tower heat load in BTU/hr.
- Estimate the recirculation rate in GPM.
- Calculate the evaporation rate in GPM.
- Calculate blowdown and total makeup at 4 cycles of concentration.
Answer
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(a) Q = 750 tons × 15,000 BTU/hr per CT ton = 11,250,000 BTU/hr. (b) Recirc = 750 × 3 GPM/ton = 2,250 GPM. (c) E = 2,250 × 10 × 0.85 ÷ 1,000 = 19.1 GPM. (d) B = 19.1 ÷ (4 − 1) = 6.37 GPM. M = 19.1 + 6.37 = 25.5 GPM. Check: M = 19.1 × 4 ÷ 3 = 25.5 GPM. ✓