The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

Hot Water Suply

SOLUTION.—Since a United States gallon of water weighs 8.3 lb., the water to be heated per hour is 200x8.3 = 1,660 lb. The temperature rise is 190—50=140° F. The average temperature of the water is (190+50) :2= 120° F. Substitute in the formula corresponding to the rule. Then, 1.25x1,660x140
5= =8 sq. ft., nearly. Ans.
300X (240-120)

25. While the rule in the preceding article will serve for a continuous coil of ordinary pipe, there are many patented transfer heaters employing several sets of thin copper tubes arranged in parallel from exterior supply and return headers, where the rate of heat transfer exceeds greatly the foregoing values. Because of the increase in the rate of heat transfer,the amount of heating surface in such heaters can be decreased, if the domestic water is circulated by a pump.

One type of such a heater is shown in Fig. 12. The storage tank a has a flanged opening at b adapted to receive a removable U-tube heat-transfer manifold c, which in turn is fitted against the two-compartment header d. The upper compartment of this header conveys steam, received through the supply pipe e, to the U tubes in the manifold c, and the lower compartment of

the header d receives the condensate from the tubes and permits it to drain at /. Cold water enters the tank through the inlet g under the heat-transfer element, and the heated water leaves at h. The tank is supported by saddles i and is provided with a pressure relief valve j. There must always be such a relief valve on a hot-water heater because of the possibility that for some reason or other the water valves might be all closed, and cold water, heated to 160 degrees and restrained, easily could burst the tank.