Document Qg31RdqN10avgVZrKqodOGdVE

438 CHAPTER 18 1954 Guide deg below 65 F. For any one day, when the mean temperature is less than 65 F, there are as many degree-days as there, are degrees difference in temperature between the mean temperature for the day and 65 F. De gree-days may be calculated on other than the 65 F base for use mainly for warehouse and other industrial spaces in which temperatures to be maintained are considerably below the 68 to 72 F range. They are listed in a later section of this chapter. Studies made by the National District Heating Association11 of the metered steam consumption of 163 buildings located in 22 different cities and served with steam from a district heating company, substantiate the approximate correctness of the 65 F base chosen by the gas industry. Table 2 lists the average number of degree-days which have occurred over a long period of years, by months, and the yearly totals for various cities in the United States and Canada. The number of degree-days for United States cities were calculated by taking the difference between 65 F and the daily mean temperature computed as half the total of the daily maximum and the daily minimum temperatures. The monthly averages were obtained by adding daily degree-days for each month each year and dividing by the number of days in the month; then totaling the respective calendar monthly averages for the number of years indicated and dividing by the number of years. The total or long term yearly average degree-day value is the summation of the 12 monthly averages. Degree days for Canadian cities were supplied by the Canadian Meteorological Division of the Department of Transport, and were computed from the mean tem perature normals on record for the various stations. Any attempt to apply the degree-day method of estimating fuel con sumption for less than one month would be of very little value. It should be noted that this method of calculation is based on a long term average and cannot be expected to coincide with any single year in calculating fuel requirement. Individual yearly degree-day calculations may vary as much as 20 percent above and below the long term average. If the degree-days occurring each day are totaled for a reasonably long period, the fuel consumption during that period as compared with another period will be in direct proportion to the number of degree-days in the two periods. Consequently, for a given installation, the fuel consumption can be calculated in terms of fuel used per degree-day for any sufficiently long period, and compared with similar ratios for other periods to determine the relative operating efficiencies with the outside temperature variable eliminated. Computation and Application The general equation for calculating the probable fuel consumption bji the degree-day method is: F=UXNXDXC, (4! where F ** fuel consumption for the estimate period. U -- unit fuel consumption, or quantity of fuel used per (degree-day) (building load unit). N = number of building load units (when available use calculated hourly loss instead of actual amount of radiation installed). D -- number of degree-days for the estimate period. Cf = temperature-correction factor from Table 3. .^ , Values of N depend on the particular building for which the estimate is ^e2, CmBS IN THE Station Years * Ala.. Aria. Anniston............... .05/06-40/41 iJirzmngham... .A'9S/99-45/46 Mobile..................... 198/99-45/4$ Montgomery........ 98/99-45/46 CNstfn..................98/99-40/41 hoem*................... {98/99-45/46 Yuma...................... 198/99-40/41 B0 Q -z<9 w*n4 < 5 BK. < < S '" 10; 135 388 600 609 513 361 152 586 691 497j 313 130 4 71 244 673 377; 397 314; 176 62 484. 494 405. 239 23 3! 10 0 18 166! 384j 402 263j 164 47I Ark... Calif.. * Bcntonvilie......... I!0rw6/0475-/4406/41 Fort Smith.........A!S8/99-45/46 Little Rock...... A 98/99-45/40 Jp*eka.................. .98/99-45/46 Fresno.. ...........A 98/99-45/46 Independence.... 198/99-40/41 Angeles...... 98/99-45/46 .............'- 17/18-38/39 a sssai a. -! 1| 306- 318 182! M 38 216: 516 810 879 716 519 ? 5JS ill 763 615 390 olJ 888 704 579' 367 274 344 411 j 518 541| 478 504 Sj j! ,771 309, 5621 573 380 289 2J 2lj 512) 778 799| 619, 477 0 0- fjj |}J; 225! 272! 235, 212 .19 217f 416 447i 243, 124 336 263 282 317 425 467: 406 437 413 415 363 38/39-40/41 (, ,, 44/45-45/46 41 Sacramento........... 198/99--45/46 48 San Diego........ A 98/89-45/46 San Franciaoo.... 98/99-45/46 48 48 Colo... S?n ...........: 08/07--40/4ll Denver.................. 98/99-45/461 Durango......... 04/05-40/41 35 48 37 Urand Junctinn. .198/99-45/46! I^dville................107/08-40/41` 48 34 Conn.. .............. A;98/99-45/46 Hartford...........A .04/05-45/46 D. C.. Fla.... Now Haven... .A 98/89-45/46 Washington ....... j98/99-15/46 Apalachicola......... 13/14-45/46 Jacksonville........ 98/89-15/46 Wes`............. 98/99-45/46 48 42 48 48 33 48 43 Snmi. ..................11/12-45/46 35 Pensacola-............|13/14-45/46 33 Ga. .............. A 98/99-45/46' .48 ................ 88/99-45/46 Augusta.............. 98/99-45/46 4,,8 0 2 5 1 196 21 8 252 01 1152 19 179* 121 21| 62 8 1261 411 37[ 201J 535 345 592' 601 4191 328 332 582 595 405 326 143 2521 300 257 230 241! 420 460 340 317 329 512 5271 383 ' 339 716 1005 1023 897 790 86111204,1271 1002 859 178 202 172 272 280 J! !!38 1218 8*3 671 Vi . 6?9i Ml 1139 1413 1470 1285 1245 in! HZI73033I in? 370 692 11004625 11014527,1068276 785294 1,1 ?! 34| fff lOIVfllOS 1023 840 42, 251J 553 872 928 834 624 154! 300 323 252. 159 144 294: 302, 244 131 *! 14|':2I 15 15 41 63 45| 28 305 332 255 162 149 1571 126 62 644' 660 6631 382 629: 533 448 274 ThVmM Idaho.. :* 48 1| ^45 206 ,*& 395 ?! 17.i 136' 38? SS3 3 III 33 Chicago.::: ::; 9l/K/j 9.107 , 378 688 932 992 779 603 21 173 473 *21 1159 1224 1004 845 0 20 181. 493 823- 878 748 512 Ind. Iowa Kan... ....... A 05/06-45/46 Springfield............ 88/89-45/461 fTMnaville......... A 98/91M5/46; Fort Wayne A 11/12-15/46 feyaTcStr--98^/9999--4455/^46 1 Terre Haute.. Charles City. Uavenport. Ues Moines. Dubuqu Keokuk 18/19-31/32 12/13-45/46 04/05-45/46 98/99-46/46 98/99-45/46 98/99-45/46 Dodge City....A 98/98-45/48 > &f 2i 88 88 1.H1 III J116121* '080 861 1 'I IFiF"3 5* 270 627, 993 1072 897 687 24 164 480 906 1362 1535 1281 995 6 91 344i 748 1178T291 1111, 835 '?6 ,13032: 345042! 7|0687 11220449 1132^0 1I113M2 981453 1?' iZ ?S2 530 407713191 1025 761 I! 402, 844 1273 1402 1206 909 *8, 370 !060,1144 954 712 59; 275; 6411 99s|l04S 868j 668 mi 139 Ky,. La. . Me... sfenfc:::::Lw^ Greenville............. 07/08-40/41 s" Si 6M m?! 282 98' , 158, , 146. 41! 221 35' 217 48 258 0: 23 4 71 271 528 1006; 917j 659 576, 947 1016, 838 604 549 881 931 816 688 601 918 964 862 650 _145 ,304 323 247i 129 276' 506! 531 415 241 827 1224 1364(I238;i080 326' 116: 131 290, 103' 298. 93' ' 352 123 If 31 1 0, 79! 10, Oi 778' 630. 301 Portl.,,j . 42/43-15/46 Bahi?,, d............A 98/99-45/45 Baltimore.......... 08roo_j.,,; 28! m J?31?!3 J434 1625 1443 1251 nl *] $$) 794 1182 1188 997 f 33. 227 528 RKfi qoi 96 12! >