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204 CHAPTER 13 1960 Guide Table 22 .... Instantaneous Rates of Heat Gain Due to Transmitted Direct and Diffuse Solar Unshaded Skylights of Hollow Glass Block of Types VI and VII Patterns For Char Atmotphons and 18 Deg Dodtoation, North (August I) Note: for total Instantonooas hoot gain odd these rates* to table 23 values Radiation by Insfonfonoow Hoot Gain in Btw per (fir) (sq fir)* s"r"" 5 a.m. 6 7 8 7 p.m. 6 5 4 Typo VI North latitude 30 40 50 00 1 344 787 11 13 14 Typo VU North latitude 30 40 00 34 10 11 19 19 93 10 2 11 1 12 19 19 20 31 29 29 23 22 41 38 38 26 23 49 44 37 27 22 62 46 * Velas* far Typo V} ese for psoet as assembled. Values far Typo Yll era for glass Mock only. 8m text. 50 1 6 11 18 26 33 38 39 Sun Hoe 5 a.m 6 7 8 7 p.m. 6 5 4 93 10 2 11 1 12 Table 23 .... Instantaneous Rates of Heat Gain by Convection and Radiation from Unshaded Skylights of Hollow Glass Block of Types VI and VII Patterns for Clear Atmosphere and 18 Dog Dscftoation, North (August I) For 80 F Indoor Temperature ______________________ Note: For total instantaneous hoat gem, odd them values to Table 22 values_____________________ instantaneous Heat Gaia to 6tu per (hr) (*q ft}* Sun Time 5 a.m. 6 7 8 Typo VI North Latitude 30 40 -9 -9 -9 -9 -9 -9 -7 -5 50 -9 -9 -8 -4 Typo VII North latitude 30 40 -9 -9 -9 -9 -9 -9 -7 -7 50 --9 -9 -9 -5 Sim Time 6 7 8 9 10 11 12 1 p.m. 2 3 4 45524 4 14 14 13 11 11 11 21 21 19 16 16 15 29 27 25 20 20 17 34 32 29 25 23 22 37 34 31 27 28 24 37 35 32 28 26 25 34 32 29 28 25 22 9 10 11 12 2 3 4 5 29 28 26 24 23 6 22 22 22 20 20 7 14 14 14 13 13 * Values tor Type VI era for penal as assembled- Values for Type VII ere for glass block only. See text. 22 19 13 5 6 7 Table 24 .... Approximate Corrections to Tables 13 and 21 for Deviations from Indoor and Outdoor Design Temperatures For each degree the design room temperature exceeds 60 F. subtract cor rection.* For each degree the design outdoor dryhafb temperature exceeds 95 F, add correction." Apply these corrections to each votes hi Table 13 or Table 21. Glass Type Correction Btu par (hr) (sq If) Single fiat or rolled figured glass Double fiat glass and glass block 1.0 0.5 * If temperature is lea than 80 F, add correctionb If temperature is lees than 9$ F, subtract correction. Where air-conditioning supply and return ducts pass through unconditioned spaces, there will be a transfer of heat from these spaces to the air in the ducts, even though these ducts are well insulated. An allowance should be made for this heat gain and included in the heat estimate so that air can be supplied at a temperature low enough to offset the rise caused by this heat gain (see Chapter 21). There will also be some heat gain to the air in ducts passing through conditioned spaces, but since a cooling effect is produced in the space through which the duct passes, this is not a loss and usually can be compensated for by adjustment of air quantities between the various spaces. No comprehensive data are presently available for use in design load estimates to evaluate the interior load-lag Cooling Load 205 Table 25 .... Shade Factors for Various Types of Shading Type ofi Shading Finish on Side Fxpomd to Son Shedo Factor Canvas awning top and sides tight against building Inside roller shade, fully drawn* Inside roller shade, fully drawn* Dark or medium Dark or medium White, cream Medium Dark Inside Venetian blind, slats set at 45 degb White, cream Medium Dark White, cream Diffuse reflecting aluminum metal Inside Venetian blind, slats set at 45 degb Inside Venetian blind, slats set at 45 deg* Outside Venetian blind, slats set at 45 deg6 Outside Venetian blind, slats set at 45 degb- * extended as awning fullv covering window Outside Venetian blind, slats set at 45 deg, extended as awn- ing covering % of window* Medium Dark White, cream White, cream White, cream 0.25 0.35 0.41* 0.81 0.71 0.81 0.91 0.56* 0.45' 0.65' - 0.75f 0.15' 0.15' 0.43 Dark*- < Green tint"-' Outside shading screen, solar altitude 10 deg Outside shading screen, solar altitude 20 deg Outside shading screen, solar altitude 30 deg Outside shading screen, solar altitude, above 40 deg 0.52 0.40 0.25 0.15 0.46 0.35 0.24 * WrJW shade* axs to be opaque- Sotos white shade* may transmit considerable solar radiation. For white translucentabide* fully draws use 0 55 and for ball drawn use 0.77. b VMtmn blinds an fully drawn and cover window. It b Besomed that the woopant will adjust slate to prevent direct rays tram passing between slate. If slate are fully dosed (date set at 00 dec) use same factora as used for roller shads fully drawn. ` Commercial >'* with wide date. The sun mayshine on window throoch sides of shade. Estimate the exposed potion e# class as unshaded. d shade, hronse. Metal slate0.OS inches wide 17 per inch and sat at 17 dec ancle with hortoontal. At solar altitudes below 40 deg some direct solar rays an allowed to pna between elate, and this amount becomes prugrendvdy greater at low adar altitudea * Qimm--i aluminum shade. Slate 0-067 inches wide, 17.5 per iTM**, set at 17 deg angle with boriaontel. At solar altitudes below 40 deg some direet edar rays are allowed to pees between elate and this amount becomes progressively greater at low solar altitude. effect, bat several investigators11' w>se- *7 " have znade"a study of the problem and have presented many useful data. Tables 9, 10, 12, 13, 17, 19, 20, 21, 22, and 23 are all based on instantaneous rates of heat transfer. Hence, practical judgment and experience offer the only basis of procedure. Until the needed data become available, it is recommended that the noncontinuous load be averaged over two or three hours during the time of maximum load, when determining the total instantaneous cooling load where a large portion of the heat gain is radiant. -This suggestion applies only to conditions near the time of mMrimum heat gain, as the heat stored within the structure would necessarily appear in the cooling load eventually; but if it appears at a time when the gain from outdoors is relatively low, the equipment will be able to maintain satisfactory conditions within the range of maximum capacity. LOAD FROM INTERIOR PARTITIONS, CEILINGS, AND FLOORS Whenever a conditioned space is adjacent. to another space in which a different temperature prevails, the transfer of heat through the separating structural section must be considered. Calculations are made according to the relation: q = UiAi(t> -- U) Btu per hour. (6) tchert u,-acoefficient of overall heat transfer between the adja cent and the conditioned space, Btu per (hour) (square \ foot) (Fahrenheit degree). Table 26___ Length of Horizontal Projection Required for Shading Windows and Walls For Sfcodtog 10 ft Down From Protection For April II Through September I Sun Tuan Protection in Fool latitude AM-* l N N E .SE s SW 30 Deg north 40 Deg north 50 Deg north 6 am. 7 8 9 10 11 12 6 p.m. 5 4 3 2 1 17.4 5.6 2.0 0.6 11.2 6:3 3.3 1.1 17.4 10.8 6.3 3.1 13.8 9.7 7.1 4.7 2.9 0.9 2.5 3.5 3.9 4.1 0.9 4.1 2.9 5 am. 6 7 8 9 10 11 12 7 pm. 6 5 4 3 2 1 12.0 3.5 9.7 18.9 16.1 4.7 11.2 11.6 1.3 6.5 9.1 3.1 6.5 4.3 1.8 4.3 5.4 5.8 6.1 2.2 6.3 4.3 5 a.m. 6 7 8 9 10 11 12 7 p.m. 6 5 4 3 2 1 8.4 1.6 3.7 9.4 19.7 18.9 6.5 3.1 12.8 14.3 7.9 0.6 7.6 11.6 8.4 0.6 3.7 8.7 8.7 3.9 6.5 9.1 6.5 t P M --* N NW W SW S SE * Projection greater than SO ft required.