Document OzOwG14Jqgm88rj55JnB6Z4Ze

420 CHAPTER 17 1951 Guide Table 1. Average Monthly and Yearly Degree-Days for Cities in the United States, Canada and Newfoundland a (Concluded) State Station Years Ya._ Erie_________ ____ 98/99-45/46 HarrisburgA Philadelphia j Pittsburgh--^ \ 98/99-45/46 98/99-45/46 98/99-45/46 B-I-J&C. Scrantn.. 12/13-45/46 00/01-45/46 Block IslftT>d___, Narragansett Picr_j Providence, 98/99-45/46 98/99-17/18 04/05-45/46 Charlestoi 98/99-45/46 98/99-45/46 21/22-31/32 ac. 17/18-45/46 98/99-45/46 98/99-40/41 42/43-45/46 Term.. i Rapid City_ Chattanooga^____ 98/9945/46 98/9945/46 Knoxville______A 98/9945/46 Memphis______ A 98/9945/46 Nashville. Texas Abilene 98/9945/46 98/9945/46 Amarillo 98/9945/46 Austin________ A BrowESvilJe__ 26/2745/46 08/0945/46 Corpus ChristL. 98/9945/46 Dalbf 13/1445/46 Del Riou. i E3 Paso___ 05/0645/46 a 98/9945/46 Fort Worth____ AI 98/9945/46 Galveston. 98/9945/46 Houston Palestine-. 09/1045/46 98/9945/46 Point Arthur 17/1845/46 San Antonio--_A 98/9945/46 Taylor-- Utah... Modena.____4 01/0240/41 00/0145/46 Salt Lake City. Burlington , 98/9945/46 06/0745/46 29 48 40 46 Va,___ | N'Wortvhuuueuldu___ Cape Hcnry_ Lynchburg__ Norfolk- 98/9942/43 98/9945/46 98/9945/46 98/9945/46 45 48 48 Richmond_____ 98/9945/46 Wytheviliel--_ Wash. , North Head-- 02/0340/41 02/0345/46 ! Seattle,. 98/9945/46 Spokanell. Tacoma ... .... 98/9945/46 98/9945/46 Tatoosb Ialftnd___ Walla Walla 98/9945/46 98/9945/46 Yakima W. Va.1 Elkina 09/1045/46 98/9945/46 : Parkersburg Wis. Green Bay___ 98/9945/46 98/9940/41 39 44 48 48 48 48 48 37 48 48 48 98/9945/46 I Madison.___ , 04/0345/46 Milwaukee---------- Wausau__,____ __ WyoL-i, Cheyenne____ _A 98/9945/46 15/1640/41 98/9945/46 Lander....______ 98/9945/46 YeflowstoneParkl 04/0540/41 | I 42 48 26 48 48 37 <) () 1 27 i i 1 31 i 2 56 1 156 499 i S 08 371 2: 5: 209 330 62 112 283 002 t ( 7 225 1 2 37 230 ( < 9 129 c 1 27 196 5 12 8? 352 251 229 255 350 67 69 170 365 20 37 284 480 71 75 190 390 301 295 325 421 5 1(J 90 315 . 8 17 124 395 15 23 115 403 1 3 56 286 17 38 179 494 7 22 1S7 454 8 21) 145 452 13 17 124 411 26 38 216 568 V 40 46 251 587 ! 27 43 265 623 1C 225 173 424 759 1C Estimating Fuel Consumption for Space Heating 421 Values of N depend on the particular building for which the estimate is being prepared and must be found by surveying plans, by observation, or bv measurement of the building. Values of U for use in this equation are the unit fuel consumptions per degree-day, and are obtained as a result of the collection of operating information. Certain of this information is presented later, but before referring to these data attention is directed to the nature of the unit. Unit Fuel Consumptions per Degree-Day The quantity of fuel used per degree-day in a given heating plant can be reduced to a unit basis in terms of quantity of fuel or steam per degree-day per square foot of radiation, cubic foot of heated building space, or thousand Btu hourly heat loss at design conditions. A less frequently used basis is quantity of fuel per (degree-day) (square foot of floor area). In fact any convenient unit can be used to relate the consumption to the degree-day and to the building. The choice of these units requires explanation, and some discrimination and judgment. If the volume basis is used, the net heated space is prefer able to the gross building cubage, since gross cubage includes outer walls and certain portions of attic and basement space which are usually un heated. In the absence of data on net heated volume a figure of 80 per cent of the gross volume may be used to obtain the estimated net heated volume. The volume basis has been rather widely used primarily because of its facility in application. In industrial buildings it is usually easier to obtain the correct volume of a given building than to measure and evaluate the heating capacity of its heating system, or calculate its maximum hourly Btu loss. The comparison of buildings on a straight volume basis does not allow for variation in exposure, type of construction, ratio of exposed area to cubical contents, and type of occupancy.. It is considered inaccurate for purposes of estimating fuel consumption unless the buildings are of very similar nature. The calculated heat loss or its equivalent square feet of calculated radia tor surface may be used as the unit. The use of the unit equivalent direct radiation is of questionable" value when referring to heat transfer surfaces used in warm air furnace or central air conditioning systems. Where steam or hot water radiation is already installed, care should be exercised in using the unit equivalent direct radiation basis for estimating, since actual in stalled radiation may differ considerably from the exact radiation require ments. In view of all these considerations, it is believed that the unit based on thousands of Btu of hourly.calculated heat loss for the design hour is prob ably. the most desirable, although the one most widely used seems to be units offuel per degree-day per square foot of equivalent direct radiator surface. The equivalent heating load for the hot water supply is not included in the latter unit, but it generally includes the piping load. Since this unit is the one most widely used at present, the unit fuel con sumptions given in succeeding paragraphs of this chapter make use of this unit to a considerable extent, although it should be understood that most of these units of consumption can be transposed as desired. Estimating Gas Consumption Values of the Unit Fuel Consumption Constant ( U) for gas are given in Table 2 for various gas heating values, and different types and sizes of heating plants. They are based on an inside design temperature of 70 F and an outside design temperature of 0 F, and apply only to these condi-