Document mpkodmxLLR0p6M3g20MygG96k

A ppliance C a p a c ity H air Dryer. Blower Type H air Dryer. Helmet Type Permanent Wave Machine Neon Sign, per linear f t of tube Sterilizer, Instrument 306 ee o uX %c6 s DD H OCQ H2U .5 go U H< 1 to n 2Id CO .To ta l 400 2700 1870 330 850 150 0001 CHAPTER 12 O' tof) s OO oos gg 30 60 650 1200 00051 1951 Guide 9000 11500 1200 2100 2450 3850 4200 100 1 1000 00061 1800 2300 ooooo cq hj> Tp c-- oo ooo | ooooo (DOOOOQcQ OO*-O*OCOOCO ooo 7200 .9200 6000 , 8500 M a in ta in in g Rate Btu per H our 1 2500 33000 25000 25000 Manufactured Gas N atural Gas Manufactured Gas N atural Gas Adjustable orifice | Continuous Flame Heater and fan blowing air to helmets Insulated, modern N ot insulated m nwoo Et>h o m H & C 12 8o 5S a M ' <n O s ver- io ns a ( l L l e D ss iLm en egs C o ntro l a n d H a n d le s ; A-- A uto m atic M iscellaneo us D ata M anu f a c t u r e r 's R atin g W atts Btu/H r L ast D im ensio n M -- M a n u a l is H e ig h t ) n c h e sI 5400 2400 3750 0009 OoOoOoOoOo cOOtMOO rt CO CO OC5 o ss o o sg t 3 w So A) ft)' o R8 iii fcJX R a"3 1a a Fan. 80 w; Low, 300 w; High. 710 w 60 heaters at 25 w each, 36 In normal use SErt OTD VV S3 9o 9o S.S :S5 2< -For physicians: thermo stat cuts on 550 w before boiling 1100 R -S CL .R R a cq!> <3 na 3 ,<R3 8CO aaaaa a < CbWQCbQChbQC3bCQ.53ncd \ cccc c assas* ' - Burners, Laboratory Small Bunsen Small Bunsen Fishtail Fishtail Large Bunsen Cigar Lighter H a ir Dryer, 5 helmets Stoves, Oven For restaurant appliances, miscellaneous electrical and miscellaneous gas burning appliances. When these appliances are hooded and provided w ith adequate exhaust, use 50 percent of recommended rate of heat gam from unhoodod appliances. Cooling Load 307 the conditioned space. If the motor is' without the space, then do not divide by the motor efficiency in Equation 16. The load factor is merely the fraction of the rated,load which is being delivered under the conditions of the cooling-load estimate. Motor efficiencies may be approximated as follows: about 50 to 60 percent at J hp rating, increasing to 80 percent at 1 hp, and to 88 percent at 10 hp and above. Appliances. Care must be taken in a cooling-load estimate,to take into account the heat gain from all appliances, electrical, gas, or steam. Table 27 presents recommended data.*7 Note that the maintaining rate in Table 27 is the heat input required to maintain the appliance at the normal operating temperature even though it is not being used, i.e., no coffee is being made, ho toast is being made, no food is being cooked in the fry kettle, etc. The maintaining rate is useful in setting up a lower limit, to the heat gi" to a room from the appliance when in operation. Experienced judgment must be used in the application of data given in Table 27. Consideration must be given to the heat contributed by appli ances which are in use at the time of peak load. The quantity of heat will depend upon whether products of combustion are vented to a flue, whether they escape into the space to be conditioned, or whether appliances are hooded allowing part of the heat to escape through a stack. There are no generally accepted data available on the effects of venting and shielding heating appliances, but it is believed that when they are properly hooded with a positive fan exhaust system through the hood, 502percentjof the heat will be carried away and 50 percent dissipated in the space to be con ditioned. The same effectiveness of the hood should be figured for both latent and sensible heat. LOAD FROM MOISTURE TRANSFER THROUGH PERMEABLE BUILDING MATERIALS The diffusion of moisture through all common building materials is a natural phenomenon which is always present to a greater or lesser degree. The permeability values for various building materials are given in Table 21 of Chapter 9, together with an explanation of moisture transmission through these materials. In the usual comfort air-conditioning application, it is common practice to neglect moisture transfer through walls, for the actual rate is quite small and the corresponding latent-heat load is hardly significant. So-called vapor barriers are frequently employed in modem construction for the pur pose of keeping moisture transfer to a minimum, and reducing the de teriorating and insulation-destroying effects of moisture. Industrial jobs, on the other hand, frequently call for a low moisture content to be maintained in a conditioned space. Here the matter of mois ture transfer cannot be neglected; indeed, it is quite possible to have the latent-heat load accompanying this transfer be of greater magnitude than any other latent-heat load. The equation for computing this load is: (QIa/\" 7v000..X/yDViaffeproernPcree,sIsnu.reHg\J * _1_0_7.6' BtU per ,, , (,sq ft) (17> where M * permeability grains per (sq ft) (hr) (in. Hg). 7000 = grains per pound.