British thermal unit , types

By detinition, one calorie (International Table) is exactly 4.186 8 absolute joules which converts to 1.055 056 X 10 joules for one Btu (International Table). Also, by definition, one calorie (thermochemical) is exactly 4.184 absolute joules which converts to 1.054350 X 103 joules for one Btu (thermochemical). A mean calorie is TSOth of the heat required to raise the temperature of one gram of water at one atmosphere pressure from 0°C to 100°C and equals 4.19002 absolute joules. In all cases, the relationship between calorie and British thermal unit is established by 1 cal/(g. °C) = 1 Btu/(lb. 6SF). A mean Btu, therefore is 7So h of the heat required to raise the temperature of one pound of water at one atmosphere pressure from 32°F to 212°F and equals 1.055 87 X 103 joules. When values are given as Btu or calories, the type of unit (International Table, thermochemical, mean, or temperature of determination) should be given. In all cases for this table, conversions involving jou S are based on the absolute joule. 

FIG. 5-7 Chart for determining heat-transfer coefficient hm for film-type condensation of pure vapor, based on Eqs. (5-79) and (5-83). For vertical tubes multiply hm by 1.2. If 4T/ if exceeds 2100, use Fig. 5-8. /%p2P/ is in U.S. Customary units to convert feet to meters, multiply by 0.3048 to convert inches to centimeters, multiply by 2.54 and to convert British thermal units per hour-square foot-degrees Fahrenheit to watts per square meter-kelvins, multiply by 5.6780. 

What units are associated with energy If you have forgotten, refer back to -Table-lvl—No - confiision-exists -with-respect-tO-the ioule.. but it is necessary tp be careful in specifying what type of calorie or British thermal unit (Btu) is under consideration (there are four or five common kinds). For example, the type of calorie that is found in older tables of thermochemical properties of substances is the thermochemical calorie (equal to 4.184 J), whereas a second type of calorie is the International Steam Table (I.T.) calorie (equal to 4.1867 J). A kcal in nutrition is just called a calorie that is, a hamburger containing 500 calories really contains 500 kcal. 

British Thermal Units (BTU s) used on an annual basis per square foot by type of building. The standards applicable to a given structure are maximums. 

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