Question

The recovery time of a hot water heater is the time required to heat all the water in the unit to the desired temperature. Suppose that a 62-gal (1.00 gal = 3.79 x 10-3 m3) unit starts with cold water at 11 °C and delivers hot water at 53 °C. The unit is electric and utilizes a resistance heater (120 V ac, 3.4 Ù) to heat the water. Assuming that no heat is lost to the environment, determine the recovery time (in hours) of the unit.