Document 7RL36p780d3RGY1zOKeGyRokg

446 Table 7. CHAPTER 18 1954 Guide Various Types op Occupancy1 Steam Consumption of Buildings with Type of Building No. BLDG3- Average Volume Heated Space 1000 Cu Ft Steam for Heating Lb per DD per J000 CuFt Average Hours of Occupancy Office.....-- ........................ Office and Bank................... Office and Printing.............. Office and Theater.............. Office and Stores or Shops.. Bank.......... .......... Department Store.. Stores....................... Loft........................... Warehouse.............. Hotel and Club.............. Apartment or Residence.. Theater............................... Garage----\.................... Manufacturing................... Church................................................. Hospital.............................................. School.................................................. Municipal or Federal....................... Lodge, Gym, Hall or Auditorium. Miscellaneous..................................... 334 49 8 7 26 16 63 73 63 24 73 61 22 13 19 4 8 13 12 7 2160 3000 .1895 4950 1615 3400 310 865 2230 1795 1425 1240 1540 1350 3306 1115 3215 0.685 0.577 1.230 0.412 0.617 0.786 0.3S5 0.624 0.588 0.459 . 0.990 0.962 0.482 0.202 0.808; 0.532 1.194 0.592 0.587 0.390 0.479 12.1 13.1 17.7 12.9 13.2 11.7 11.1 10.4 10.0 9.4 22.3 21.8 12.9 21.4 <9-5 7.9 22.0 11.5 15.6 , 13.4 21.4 * Principles of Economical Heating, National Association of Building Owners and Managers. than approximately 70 F is to be used, the number of degree-days should be obtained for the new base. Example 7: An eight-story building in Pittsburgh is operated with a daytime temperature of 70 F. The calculated heat loss is 10,500 Btu per (hr) (degree temper- ,, ature difference). What is the estimated average yearly steam consumption for buiSldoinlugtiohne:atSiningc?e the average inside temperature is approximately 70 F, the degreedays from Table 2, based on 70 F may be used. Therefore, from Table 2, Pittsburgh has 5430 degree-days per normal season. IWnsertrtiinng, in Eqauation 5- : 10,500 X 24 X 5430 1,368,000 lb of steam. 1000 Consideration has been given to the difference in steam utilization of different types of buildings, and Table 7 shows actual average units for these various types. These figures were obtained from operating results in 896 buildings located in all sections of the United States. Being aver ages, and for small groups in each type, the figures may need considerable modification to allow for local variations. It should be especially noted that the steam used for heating water for service is not included in the values given in Table 7. Example 8: A store in Philadelphia with a heating system designed to maintain 70 F inside in 0 F weather has 250,000 cu ft of heated space. What would be the estimated average yearly steam consumption of purchased steam for heating? Solution: According to Table 7, a store would use 0.624 lb of steam per degree-day per 1000 cu ft heated space. From Table 2, Philadelphia has 4739 degree-days per normal year. Inserting in Equation 4: F = 0.624 X 250 X 4739 = 739,000 lb of steam. Degree-Day as an Operating Unit The degree-day is also widely used as a means of comparing the efficiency of the fuel consumption of one period with another for the same building- Estimating Fuel Consumption for Space Heating 447 Since the fuel consumption is proportional to the weather (degree-days), and since the periods to be compared may not have the same weather con ditions, the comparison can be made only after the fuel consumptions have been computed on a comparable weather basis, that is, upon the actual number of degree-days occurring for a given month and year in the city under consideration. Since fuel consumption is proportional to the number of degree-days, plant operators frequently compute each month the fuel burned per degree-day by the heating plant. The resulting unit value, by eliminating the outside temperature variable, indicates whether the operating efficiency of the plant is above or below the previous month or year. The figures in Table 8 illustrate a typical example of a method of using the degree-day for making heating comparisons for one building for two Table 8. Heat Consumption Record fob Comparison Col. 1 Col. 2 Col. 3 Col. 4 Col. 5 Col. 6 Col. 7 Total Consumption Consumption Fob Heating Avg Temp. Deo Date Lb/Dbg 65 F Base Day Lb/Dbg M Cu Ft Sept.......... 337,500 7C4 Oct............ Nov.......... 834,200 1,446,600 o d> Dec........... 2,176,400 % Jan........ *.. 2,332,200 Feb........... 2,131,100 o Mar........... Apr........... 2,021,900 1,241,500 May.......... 672,500 < . 258.600 July.......... 188,400 180,100 170,500 667,200 1,279,600 2,009,400 2,165,200 1,964,100 1,854,900 1,074,500 505,500 91,600 65 53 44 25 22 28 31 43 55 146 339 641 1,233 1,297 1,106 1,032 647 303 50 1,170 1,966 1,990 1,630 1,670 1,775 1,799 1,660 1,670 1,830 0.575 0.970 0.982 0.804 0.823 0.888 0.885 0.818 0.822 0.905 Sept.......... Oct............ 5 Nov.......... Dec........... Jan............ l_Feb........... Mar........... 13,821,000 330,200 887,100 1,525,200 2,045,500 1,933,400 1,990,200 1,984,100 146,200 703,100 1,341,200 1,861,500 1,749,400 1,806,200 1,800,100 61 52 39 28 30 30 31 167 410 812 1,120 1,044 1,111 1,021 875 1,718 1,653 1,660 1,670 . 1,624 1,760 0.431 0.845 0.815 0.817 0.825 0.800 0.868 - If, for example, the heat consumption In March, 1943, is compared with that in March, 1944, it will be found that in the latter the steam consumption is 1799 -- 1760 = 39 lb less which is a decrease of 2.2 percent. consecutive heating seasons. The heat quantity figures inserted are pounds of steam, but a similar comparison could be made using pounds of coal, gallons of oil, or cubic feet of gas. For such a comparison, a two-year record, as shown in Table 8, is often used. The year under consideration may then be compared, month by month, with the previous year. Column 3, Consumption for Heating, would be used if the same fuel is used for heating and process steam. Some reason able figure must be assumed for the process requirement and should be deducted from the amount shown in column 2. This would leave in column 3 only the fuel chargeable to heating. The degree-day values in column 5 are obtainable from the local Weather Bureau. Values in column 6 are obtained by dividing corresponding values in column 3 by the degree-days ln column 5. The heating index in column 6 is, then, a figure of heat con sumption, corrected for outdoor temperature, and should be relatively con stant month by month. Column 7 in Table 8 may be used if the heat consumption is to be compared on a building volume basis with average values shown in Table 7.