Document rxMoEReR6Qrp03827KYYmYmRa

if I; i 532 CHAPTER 28 1965 Guide And Data Book Table 1 Heat Gain Factors (Walls, Boor and Ceiling) Stop-- (*| ft) {24 M famriafioa Temp difference (gmbectrf lasp mintij storage tcap), f deg Cork or equivalent in. 1 40 50: [55 60 65 -:70 . '75' so . B5 90 95 100 105 110 115 120 3 4 ,. 5 6 7 2.4 96 108 120 132 144 156 168 180 192 204 216 228 240 252 264 276 288 1.8 . 72 81 .99 108 117. 126 135 144 153 162 171 180 189,. 198 207, 216 1.44 58 65 ` '72 79 87: 94 .101 108' 115 122 1) 137 144 15V 159 166 173 1.2 48 54 60 66 ' '72 78- "'84 90 `96 102 108 114 120 126 132 138 144 1.03 41 46 52 57 62 67 72 77 82 88 93 98 103 108 113 118 124 8 9 10, 11' ' 1 ' 12 ' ` 13 14 Triple ek"" 0.90' ' 36 0.80 32 0.72 , 29 0.66. 26 0.60 24 0.55 . 22 0.51 20 27.0 1080 11.0 440 7.0 280 'U ' 45 50 54' ~59 36 40 44 48 52 32 36 40 43 47 30 S3 36 40 43 27' 30' s 33' : 38 39 25. 28 23 ' 26 1220 1350 500 550 320 350 .30' ; ft ' 2* 31 1490 1620 610 660 390 420 36 33 1760 715 454 "63 68" 72 77 81 ` "86' 90 95' "99 104 108 56 60 64 68 72 76 80 84 88 92 96 50 54 5K 61 65 .68 72 76 79 , -83, 86 46 50 53 56 60 63 66 69 73' 76' 79 42 45 ' 48- 51 54 . 57- 60' ,.63 66 " 69 * .72 39 . 41 "*14 ^47 36 38 `41 43 so; -.52 '46 ' 49 :55 58 . 61. ``,63 .51 54 ` 56' `59 61 1890 2030 2160 2290' 2440 2560 27<X) 2840 2970 3100' 3240" 770 825 880 936 990 1050 1100 1160 1210 1270 1320 490, 525 560 595 630 .665 700 740. 770- 810,- 840, Nats: Wben wood (tads m uaed-multioty the above values by LI * weighti-specific heat above and below freezing, -its freezing temperature, and latent heat. When a definite weight of prod uct is cooled from one state and temperature, to another state and temperature, some or all'of. the'following calculations must be: made: '"V - Heat removal from initial temperature to nine lower' tern-; perature above freezing: , . . .. Q - W X c X (ti - t) (4) Heat removal from initial temperature to freezing' point of product:.- ' ' .................> ;1' . (Q - w x cx (rV-f hi ' tAt '(5),. Heat removal to freeze product: ., -Q. - W X hi,. -- : (6). Heat removal from freezing point to final'temperature below, freezing: 1 1 t` ' ' " Q - W XCi X {tf r U) (7) where- r ... . -. .. !., Q -- heat removed* Btu. ,. , W -- weight of product, pounds.( .J .. c -- specific heat of product above.freezing., Btu per, (pound) (Fahrenheit'degree).",, ....... ti -- initial temperature above freezing, Fahrenheil-- it -- towertemperatureabovefreezing, Fahrenheit. '' tf -- freezing temperature of product! Fahrenheit.' '* ky -- latent.heat of fusion, Btu per pound. : Table]_2".... Minimum Insulation Thicknesses -- 'Storage'1 . temperature . . Cor6 or equiwjtont Itfebeu ` (/ndio*) j - Nonhem . u.v. ; Sowthera u. s. , _; 50 to 60 40 to 50 25 to 40 ; 15 to 25 Oto 15 0 to'---15"- .-- 15 to --40 . . 2 -v3 t Ac 5 Q : 7 - ... 9 : - * ' '.1 3 : 4 5 6, '7 1 ) 8 ' : -! 10.: 1 Table 3 . .t-. Allowance for Sun Effect (Fahrenheit degrees to be added to the normal temperature difference '*: far beat taakogm edadotioas to compensate far ton effect wot- to be used for air eondiKoflfag darign) Typo of surface ' Ecuf. waff Soutti. West Hof, , waff' waff ' Dark ootored surfaces such as ..Slate roofingr .. , : Tar roofing, ... Black paints ' ,(1 8 , Medium colored surfaces, such as Unpainted wood Brick 'Red tile Dark cement Red, gray or green paint 6- light colored surfaces, such as ...White.stone , ' light colored cemient White paint 4". ,V';81? 20. -. 4. 6 15 2J 9* - ,.Tablei4 .... Average.Air Changes per-,24 hr^for \ Storage Rooms due-to Door Openings i'-> . ii j-.fl and'Infiltration''- (above-32 F) <: Votome. - .... Air changes . eo ft per 24 hr MO ` .44:0. -` . '300 ' 34.5 ' '400 ' ` 729.5 ' ' 500 ' '<26:0' i - 600: : , i 23.0 .- . ' 800 ...... 20.0 1,000 1,500 2,000 3,000 4,000 5,000 17.5 14.0 12.0 9.5 8.2 7:2 , Volume <*r ft Air dtaitges per 24 hr . '6,000 -'..6.5' ' ; 8,000'10,000 " 5.5 ' 4.9' ' 15,000 :.-'' '* -"'3.9 20,000 , 1:3.5 25,000, , ;i . 3.0 30,000 40,000 50,000 75,000 100,000 2.7 2.3 2.0 1.6 ' 1.4 Note: For heavy unco multiply the above vahme by 2. Far Laoc otoracB multiply the above value* by Qji. ML rr Refrigeration Load .- . : 533 Table`5 :Heat Removed in'CooGng Air to Storqge;Room Conditions-.? ;,-.j: ^ 1 '' (Sto per a> ft)~~~ - - .................. * r ... ..................... -1 temp ' 65-' -''*' ' Temperature of 00fade air, F 1 ... 90, BefatW huiuiLffly/Feramt' r so- 60 ' V50 ' 60 SO 60 . - 50 ! - '65'' ' " 60`, :- ' 55 -" . :;50,U" *-- ` 0.65 0.85 0.85 ' : 1.03 1 : 1.12 = 1.34 " ,-.1.32 :?r :i 1.54. . 40 . .,'" .:.-.35` M 1.69 '7"l'.86i- ' *- . ! t .`2.00:, 1.73 1.92: 2.09 2.24. ','"0.93J V ' 1.13 1.41 ' .. 1.62... ` i:80"' 2J00`' 2.17"5' ' 2.28 . 1.17 ' 1.37-- 1.66. : i.87 2.062.26 2.43:,.' 2.63 1.24 - 1.54 1.58 -- 1:44 -- 1.74- 1.78 ,..1.72 . .. 2.01, . -..2.06- 1.93-:- ' 2.22 -... -:-2.28 -2.12 :. ;^2l'42r` 2.31 - 2.62 - ' C2.491 ' '. _2.79;'-"r 2.64 ' " 2.94'":`. 2.47' 2.67 2.85 .. 2:95' 60. 2.15 -- 2.44;. '.*2.65 2.85 .i ' --3:06 .'3,24 3 35, - ` ' i., , mTemperature of outride air, F Storage roeai;. 1. ... F ! p-' ffofatfve huaidcfy/Feradit: v : i ..... 70 . (B0f,. ` ' '30 ' ' -..... . 'r 25:.- 20.. . ,15 . ; - 10' ' ' " b.24 ' ; :J!.0.41 . 0.56,.; .0.71.'.. 0'.85 ' - 0.29 - : .0.45 : 0.61;:- 0.75 . 0.89 -! :o.58 " 0.75 : ., 0.91;, - 106 ,, ' i.`i9 80 ... 0.66 : 0.83 0.99 1.14 1.27 50 , 2.26 2.44 2.62 2.80 . 2-93, . fi 2: 53 " ' 2.71 2.90 3.07,\A ' .3.20 50:; ['. -.-ACC ` 2.95 3.14 3.33 3.51 3.64 ' 3.35 ' ' -.3.54:: 3.73 3.92 4.04.t. 5 .0 , . -5 ' ' . .: ..,-10... ..J . . --15; r/-- ,. -25... .. ' --30t, ; .0.98. ,1.12 . , . 1.23 . . . . 1.35 1.50 1-03-.;.. -1.34.,,. . 1.17 . .... 1.48 1.28*.,. ' ` ~1.59 } : 1.41.:. . 1-73,:,. . .1.53: ,.s . 1.85 , 1.42 T-, f! . 3.12`,'!:; 1.56, .. :3.28. j 1.67 3.41 1.81' " 3.56 " 1.92- 3.67' : .3.40 !,..3.56 . . 3.69 ' ' 3.85" ' ';3.96" l'63!" " : 1.77. . .1.90 ... '1.68.V. , 2.01. 1.80. -. - 2.12 1.95 2.29 , 2.09 , 2.21 2.38 ' :\3.88 .4.00 ' -4.21 ' +18 , j4.30.. 4.51 ' 3.84. . . 4.Q1 4.15 4-.31' > 4.42- . 4.66 .4.78 4.90 :.. 4.27 v.,,4.43...... " 4.57 . 1'4:74 '""' r '4.86'S' `j' V :5.10 ' :.5.2i : 1 --5.44 ,<ftr;=;specific heat of product below freezing'Btu per.(pound) .! -: (Fahrenheit degree)./. -.. ` 4" final temperature below freezing, Fahrenheit:' ' '' The.product load is represented.by-the sum of the-several loads given above.-if it ia necessary to remove the heat from the product in a given number of hours, the equivalent'load, based on 24 hour calculations, is found aaToilows:,;' Btu per 24 hr Product load X 24 Hr reqd for product load Specific heats above and below freezing and latent heats 'of faeum for many products are given in Table 4, Chapter 69. It should be noted that the latent heat of fusion has a definite relationship to the water content of the produetj in ihe ab- saice of data bn the latent heat of a product and with a knowldge of its moisture content, the latent heat may be estimated by multiplying the percentage of water expressed as a Hommitl by 144, the latent heat of fusion of water". Most food products have a freezing temperature in"the range of 26 to 31 F, with an average freezing temperature of about 28 F. If the exact "esing temperature is unknown, it may be assumed to be irJfr a ^yeQgg^^.f00d:freeaiig> .refer to Section V; of,the 1964 Guide And Data Book. V\...;r . Example 1:100 ib of lean' bek axe to be cooled from 65 to 40 F, "^bi.ch rt is to;be frozen and cooledtoOF. ............ .Jt To.cool.from 65 F.tb 40 F u^chiU room: t, . 100 X 0.77 X (65 - 40) - 1925 Btu i1" - To cool from 40<F to freezing point in freezerr ' ' V' lOO'X 0.77`x.(40 - 28) - 924 Btu` r`v -, To.freeze;- .. .. . ............ o -.100 X 100 - 10,000 Btu .! ... .i To oool from freezing point to storage temperature: - i00 X 0.40 X :(28 -.0) -j'1120 Btu ; ;-v:.. - j'` ^ -Total --. 1925 +924 + 10,000 + 1120,'- 13,969.Btuu '" '' Fresh'fruits and1 vegetables give'up heai during storage. It' must be remembered-that they are;alive and' continue rto undergo changes' during storage/TTie most important of changes'js'produced-by'respiration, a process in which the oxygen of the eh is combined with the carbon'of;the` plant tisoie. During this process, energy is released in the form of heat. The amount of heat liberated varies with the type and temperature.o.f-the product. Hie'colder the product* ithe less the heat of respiration. The rate of evolution of heat of various products is hsted in Table 4, Giapter69. - heat gain from people, lights and OTHER SOURCES AH electrical energy dissipated in the refrigerated space (lights, motors, heaters, etc.) must be included in the heat load. Each watt is' equal to 3.42 Btu per hr. Heat equivalents of electric motors are shown in Table 6. People give up heat at