Question

Water flows with 1 gal/min and 10oF temperature difference. Calculate the ton of cooling load ?

Answer 1

The ton of cooling capacity is a fascinating unit, coming as it does from the refrigeration techniques of the 19th century: namely, 1 ton of cooling capacity is equal to the heat energy you can absorb by melting 1 ton of ice every 24 hours. It turns out that's 12,000 BTU/h or 3517 W.

1 gal/min = 8.34 lb/min, since water weighs 8.34 lb/gal. 8.34 lb/min * 10oF = 83.4 BTU/min, since 1 BTU is the heat required to heat 1 lb of water 1oF. There are 60 min in an hour, so this is 83.4 x 60 = 5000 BTU/h, or 5000/12000 = 0.417 tons of cooling capacity, assuming the limiting precision is that of my lb/gal conversion factor.