Water is pumped through pipes embedded in the concrete of a large dam. Water enters the pipes at 100 psia and exits at 20 psia. In picking up the heat of hydration of the curing concrete, the water increases in temperature from 50 to 100 F. During curing, the heat of hydration for a section of the dam is 140,000 Btu/hr.

Assume that the pump makes up the pressure lost through the pipes. Ignore changes in kinetic and potential energy.