Document Ed4bJpK7DYERrjkQdb8ZyZOrn

428 CHAPTER 17 1952 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. Degreedays may be calculated on other than the 65 F base, but are seldom used and are of little value except for example, in warehouses, where the inside temperature to be maintained differs greatly from the usual inside temper ature range of 68 F to 72 F. 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, Canada and Newfoundland. The values 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 averageswere 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 by the degree-day method is: F = U X N X D X C, (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 heat loss instead of actual amount of radiation installed). D = number of degree-days for the estimate period. Ci = temperature-correction factor from Table 3. Values of N depend on the particular building for which the estimate is Estimating Fuel Consumption for.' Space; Heating 429 Table 2. Average Monthly and Yearly Degree-Days for Cities in the United States, Canada and Newfoundland*' b (Base 65F) State Station * , C8 3 i iYears oo.cB<a oSfc > g Z *- 6 p <5 CEaO >o da ZQ nH 3 fa a e> < h< a 2 P-9 '3S Eo* hR 5* Ala.... -Anniston............. 05/08-40/41 36 Birmingham___I 98/99-45/4( . 48 Mobile................. 98/99-45/46 48 - Montgomery.;... 98/99-45/46 48 Aria. .. Flagstaff............... 98/99-40/4] 43 . Phoenix................ 98/99-45/41 ' 48 Yuma................... 98/99-40/41 45/46 44 Ark.... Bentonville...... 06/07-40/41 35 - Fort Smith.... .A 98/99-45/41 48 Little Rock.....A 98/99-45/41 48 Calif... Eureka.................. 9S/SfM5/4f 48 ' Fresno............... A 98/99-45/46 ..48 ` Independence.-... 98/99-40/41 43 Los Angeles......... 98/99-45/46 48 Needles................ 17/18--38/3S 22 Point Reyes........ 98/99-40/4] 43 Red Bluff..........A 98/99-33/34 (] 0 1(3 136 388 60C 609 513 361 162 37 1 ( : 1< 11 .348 58- 59: 49] 31? 130 23 ] ( . ( 1 4* 208 37! 39] Zh 175 "52 3 . c ( ( i 7: 271 48 49* 405 231 85 10 0 4; . 7( 24* 573 84] ill: 116] 97( 889 661 469 190 i ( ( 18 10{ 3& 401 26? 1& 47 7 0 2071 7241 (( 3 ' 1 (( (. ( 281 281 C( CC 1C (6 35C 33f (1 31 21( 12 128 11 m 274 344 i 1\ 28 218 f 4c (] If 263 282 11? 30f 318 182 85 25 ] ( 51C 81( 879 71e 619 247 86 7 41C 711 76? 615 390 154 36 1 38? 668 70< 579 367 145 31 1 411 518 541 478 504 ,44C 391 307 30S 565 57? 38C 289 152 52 4 512 778 799 619 477 267 120 * 18 110 225 272 235 212 15i 102 2] 217 41f 447 243 124 2f 3 0 317 425 467 406 437 412 415 363 4758 2403 3834 1391 '1495' 4474 Colo... 44/45-45/46 41 SRaancraDmieegnoto.....,....A.. 98/99-45/46 98/99-45/46 48 48 San Francisoo.... 98/99-45/46 48 San Jose............... 06/07-40/41 35 Denver................. 98/99-45/46 , 48' Durango............... 04/05-40/41 37 Conn.. D. C.. Fla.... Grand Junction.. 98/99-45/46 -.48. Leadville.............. 07/08-40/41 34 Pueblo.......... . .A 98/99-45/46 .48 Hartford............A 04/05-45/46 42 New Haven.... A 98/99-45/46 48 Washington.......... 98/99-45/46 48 Apalachicola........ 13/14-45/46 33 Jacksonville......... 98/99-45/46 -48 Key West............. 98/99-45/46 48. Miami.................. 11/12-45/46 35 Pensacola............. 13/14-45/46 33 Tampa...............A 98/99-45/46 48 98/99-45/46 Augusta................ 98/99-45/46 48 Macon................... 99/00-45/46 47 Savannah......... A 98/99-45/46 48 Thomasville__ 05/06-40/41 36 Idaho.. Boise.................. A 93/99-45/46 48 Lewistown........... 00/01-32/33 33 Pocatello............... 98/99-45/46 . 48 Ill........ Ind.... Chicago................ 98/99-45/46 Peoria................ A 05/06-45/46 Springfield........... 98/99-45/46 Evansville.........A 98/99-45/46 Fort Wayne___ A 11/12-45/46 Indianapolis. .-. 98/99-45/46 Royal Center___ 18/19-31/32 48 41 48 48 35 48 14 Terre Haute........ 12/13-45/46 Iowa .. Charles City........ >4/05-45/46 Davenport........... 98/99-45/46 Des Moines.......... >8/99-45/46 34 42 48 48 Dubuque............. 98/99-45/46 48 Keokuk................ >8/99-41/42 44 Sioux City........ A >8/99-45/46 48 Kan... Concordia............ >8/99-45/46 48 Dodge City___ A >8/99-45/46 48 lola........................ 05/06-40/41 36 Topeka................. >8/99-45/46 48 -Wichita.............. A >8/99-45/46 48 Ky.... Louisville............. >8/99-45/46 48 Ia....... Me... - Lexington............. 98/99-40/41 New Orleans....... 98/99-45/46 Shreveport........A >8/99-45/46 Eastport............... 98/99-45/46 Greenville............ >7/08-40/41 43 48 48 48 42/43-45/46 38 Portland........... A 98/99-45/46 48 Md... Baltimore............. 98/99-45/46 48 0 2 0 12 97 345 592 601 419 328 178 72 . 9 2653 1 15 98 332 582 595 405 326 202 101 21 2680 5 1 9 60 143 252 300 257 230 172 118 .49 1596 196 179 121 139 241 420 460 340 317 272 255 197 3137 . 21 21 52 151 329 512 527 383 339 249 167 72 8 8 126 411 710 1005 1023 897 790 616 275 64 5839 25 37 201 635 861 1204 1271 1002 859 1 1 59 347 743 1138 1218 883 071 377 152 23 280 332 509 841 1139 1413 1470 1285 1245 990 740 434 10678 . 3 4 91 377 730 1042 1042 875 724 446 195 : 29 5558 3 16 105 370 692 1065 1157 1062 859 524 213 47 6113 3 11 88 341 658 1017 1109 1023 840 522 221 47 5880 0 2 42 251 553 872 928 834 624 340 101 . 14 4561 0 0 1 23 154 300 323 252 159 38 2 0 1252 0 0 0 25 144 294 302 244 131 . 42 3 0 1185 0 0 0 0 2 14 .21 15 7 0 0 . 0 59 0 0 0 0 15 41 53 45 28 3 0 . 0 185 0 0 0 25 159 305 332 255 162 39 4 0 1281 0 0 0 6 60 149 157 126 62 11 0 0 571 0 0 0 0 4 85 312 529 533 448 274 107 13 5 91 322 532 538 449 278 108 14 1 . 2306 1 2338 0 0 1 45 206 390 395 332 194 `66 6 0 1635 0 0 2 48 208 361 359 299 178 52 5 1 1513 9 17 136 385 717 1025 1077 840 688 440 252 92 5678 5 9 107 378 688 932 992 779 603 371 193 52 5109 12 21 176 475 .821 1159 1224 1004 845 550 330 124 6741 6 7 88 337 .712 1116 1218 1080 861 531 259 67 6282 4 8 88 350 730 1126 1231 1035 790 436 178 28 6004 0 3 65 286 664 1056 1151 977 719 377 132 16 .5446 0 1 35 211 544 888 948 822 682 288 -85 , 6 *4410 6 13 106 374 737 1107 1211 1052 864 '504 217 41 6232 1 4 66 297 660 1032 1102 973 737 410 154 22 5458 n 16 116 373 740 1104 1239 976 860 502 245 54 6239 0 3 62 270 627 993 1072 897 687 358 133 15 5117 8 24 164 480 906 1362 1535 [281 995 552 255 62 7624 2 6 61 344 748 1176 1291 1111 835 448 171 29 6252 1 6 102 354 767 1204 1320 [132 843 446 171 29 6375 3 12 123 402 808 1249 1380 [190 915 493 204 41 6820 1 3 71 303 680 1077 1191 1025 761 397 136 . 18 5663 3 11 128 402 844 1273 1402 [206 909 485 202 40 6905 1 3 68 288 670 060 1144 954 712 365 142 18 5425 1 3 59 275 641 998 1046 868 668 351 139 20 5069 0 1 40 236 579 030 1026 817 599 282 98 8 4616 0 2 56 254 623 013 1096 917 659 326 116 13 5075 0 1 41 221 576 947 1016 836 604 290 103 9 4644 0 1 35 217 549 881 931 816 588 298 93 8 4417 1 3 48 258 601 916 964 862 650 352 123 14 4792 0 0 0 23 .145 304 323 247 129 31 1 0 1203 0 0 4 71 275 506 531 415 241 79 10 0 2132 158 146 271 628 827 224 1364 238 080 778 530 301 8445 69 113 315 643 1012 .464 1625 443 251 842 468 194 9439 28 48 182 466 794 182 1309 188 997 671 376 136 7377 0 1 33 227 526 855 921 837 637 343 95 12 4487 * Computed from daily temperatures recorded by- United Statee Weather Bureau stations over a varied number erf seasons as indicated in the 3rd and 4th column of the table. Degree-day data for airport stations ue not included in this table. The data for United States cities were computed by .the United States Weather Bureau in 1946 and 1947 in accordance with the requirements of the National Joint Com mittee on Weather^Statistics. The data for a number of the cities listed are based on readings at more than one official city weather station during the periods of analysis, but the slight difference in the readings would not appreciably affect the resultant. " Letter A indicates city office and airport records combined.