Chapter 3: Energy from the Sun - Wood, Wind and Water

One therm corresponds to a unit of gas with an energy content of 100.000 BTU (105 BTU), delivered in a volume of 100 cubic feet at a pressure of 14.73 pounds per square inch at 60 0F, just a little higher than the pressure of the atmosphere at sea level, 14.70 pounds per square inch. ................
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