Document QgG8r0bJaE0kgN0Bz8YR7zYKv

Heating Ventilating Air Conditioning Guide 1939 Chapter 12. Heat and Fuel Utilization. Table 8. Steam Consumption for Various Classesof Buildings3 , (Heating Season Only) Building Classification No. OF Buildings Listed Steam Consumption . Pounds pbb Degree-Oat--65 F BasisS Per M Cu Ft of Heated Space Per M Bin jerHroI HeatLosb i. Apartments........................ Hotels................... .............. Residences......................... Printing............ ...... ....... --- Clubs and Lodges..---- Retail Stores.....^..:.:::.:...: Theatres.__________ :....... : Loft and Mfg..--...... Banks____________ ______ Auto Sales and ServiceChurches............................ . Department Stores______ Garages (Storage)'.... ..... Offices (Total)__________ Offices (Heating only)--. 16 10 12 . ,r - 10 18 6 16 7 8 6 14 6 35 35 . 1.78 1.46 1.32 1.25 0.96 0.90 0.90 0.89 0.88 0.83 0.58 0.57 0.42 1.09 0.975 97.5 80.6 64.2 105.5 77.0 80.6 75.0 72.3 45.2 62.2 49.4 60.7 72.3 70.0 .65.4 0.359 0.371 0.268 0.498 0.283 0.238 0.283 0.256 Includes steam for heating domestic water for heating season only. . bHeat losscalculated for maximum design condition (in most cases 70 F inside, zero outside). Equivalent steam radiator surface. dThe figures are a numerical--not a weighted--average for the several buildings in each class. Based on zero consumption at 55 F. with a heating value of 1000 Btu pier pound is used so that no correction is necessary for heating value in the usual case. In comparing values from'different cities, correction should, be made for design temperature (see Table 5) when the unit figures are in terms of square foot of radiator or iOOO Btu per hour calculated heat loss, but not when the values are in terms of building volume or floor space. .Consideration has been, given to the difference, in steam utilization of different types of buildings and Table 84 shows actual average units for these various'types. These figures are obtained from operating results in :: I 2- v. (J Table 9. Building Load Factors and Demands of. Some .Detroit Buildings3 Building Classification >... Load Factor Hotels " _________________ : Printing....................;..i.............. --------- Apartments_________ ll...__ :_____^.................... ......... . 0.318 0.316 0.287 0.263 ' : 0.255 0.238 0.223 0.203 0.158 0.138 0.126 Lb of Demand per Hr ' per Sq Ft of Equivalent Installed Radiator Surface 0.184 0.207 0.217 0.209 0.225 0.182 0.248 0:158 0.152 ' . . 0.145 0.151 Report 'of. Commercial Relations Committee, Proceeding?, National District Heating Association, 1932. The Heat Requirements of Buildings,' by J. H. Walker'arid G. H. Tuttle (A.S.H.V.E. Transactions, tVoL 41, 1935. p. 171). [246 , -Mings located in 21 different cities in the United States. Being ;196 bin ^ for sman groups in each type, the figures may need cona-4erble'modification to allow for local variations. It should be especially sl"'e*f tjiat tije steam used for heating hot water is included in the values n?ted in Table 8, but in the case of office buildings, the steam for heating ^T^s also shown. Presentation of the unit consumption in three ways n ^ 'ts making the estimate if either the calculated heat loss or the volume of net heated space in the building is known. MAXIMUM DEMANDS AND LOAD FACTORS In one form of district heating rates, a portion of the charge is based non the maximum demand of the building. The maximum demand may be measured in several different ways: It may be taken as the instan taneous peak or as the rate of use during any specified interval. One method is to take the average of the three highest hours during the winter. These figures are available for a number of buildings in Detroit, as shown in Table 9. These maximum demands were measured by an attachment on the condensation meter and therefore represent the amounts of condensation passed through the meter in the highest hours, rather than the true rate at which steam is supplied. There might be slight differences in these two quantities due to time lag and to storage of condensate in the system, but wherever this has been investigated it has been found to be negligible. The load factor of a building is the ratio of the average load; to the maximum load and is an index of the utilization habits. Thus, in Table 9, the theatres, operating for short hours, have a load factor of 0.126 as compared with the figure of 0.318 for clubs and lodges. PROBLEMS IN PRACTICE 1 What will be the estimated fuel cost per year of beating a building with gas, assuming that the calculated hourly heat loss is 92,000 Btu based on 0 F, which includes 26,000 Btu for infiltration? The design temperatures are 0 F and 72 F. The normal heating season is 210 days, and the average outside temperature during the heating season is 36.4 F. The seasonal efficiency will be 75 per cent. The heating plant will be thermostatically, controlled, and a temperature, of 55 F will be maintained from.ll p.m. to 7 a.m. Assume that the price of gas is 7 cents per 100,000 Btu of fuel consumption, and disregard. the loss of heat through open windows and doors. The average hourly temperature is: - \ ^ (72 X16L+ (55 X 8) = 663 p . V ^ JI The maximum hourly heat loss will be: ' II = 92,000 26,000 = 79,000 Btu. M= 79,000 (66.3 - 36.4) X 24 X 210 = 2204.6 hundred thousand Btu. 100,000 X 0.75 X (72 - 0) 2204.6 X 0.07 = $154.34 = estimated fuel cost per year of heating building.