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

Hot Water Suply

42. By using the approximate values given in the preceding article it is possible to calculate the fuel requirements for heating a definite amount of water. For example, assume that 300 gallons of water per hour is to be heated from 40° to 140° F. According to Art. 41 (a), the amount of water to be heated weighs 300x8.3 = 2,490 pounds. From (b) it will be seen that the amount of heat required to heat this weight of water from 40° to 140° F., is 2.490 X (140-40) =249.000 B.t.u.

If coal is used as fuel, it follows from (c) that 249,000:7.000 = 35.57 pounds of coal is required to accomplish the heating.

If the fuel is gas, it follows from that 249,000+490 = 508.2 cubic feet of gas must be used.

If the fuel is oil, it follows from (e) that 249,000+91,000 = 2.74 gallons of oil is required.

If the water is heated by electricity, it follows from (/) that 249,000+3,000 = 83 kilowatts of electric current is necessary.

Or, if steam is the heating agent, it follows from (g) that 249,000+1,000 = 249 pounds of steam must be used.

43. Circulation to Fixtures Below Level of Boiler.—To pipe a building so that not water can be drawn instantly at fixtures located at a lower level than that of the boiler or storage tank, is a difficult matter. To get results fairly satisfactory in this respect, a loop must be formed by running the hot-water pipe as high as possible before descending to supply the lowest fixtures. A good example is shown in Fig. 18, where laundry tubs are located in the basement of a house supplied with water from a tank in the attic. The hot-water distributing pipe forms a loop, the flow pipe of which connects to the top of the tank. A 1/2-inch relief, or expansion, pipe is located at a, which must be the highest point of the loop. This pipe allows air to escape from the loop, which would otherwise become air-locked.