Document KGyNnEnR16qapk9JqmVO2Ogv6

294 CHAPTER 13 1953 (Guide Table 22: Instantaneous Rates .of Heat Gain Dub to Transmitted Direct and Diffuse Solar Radiation1 by Unshaded Walls of 8-in Hollow Glass Block of Types II, III, TV, IVA and V Patterns Multiply the Table SO Values for Type I by These Percentage Factors For .Clear Atmospheres and,18 Deg Declination, North (August 1) For 80, 40, and 80 Deg North Latitude Note: To obtain total instantaneous heat gain add adjusted Table SO values to the' Table SI values. UfBTANTAHEous Heat Gain Due to Transmitted Solar Radiation as a Percentage oe Type i Pattern Sun .Time l Type II Pattebn l Ttpe III Pattern AM- i 05 aon. 87 9 10 11 12 67 pan 5 4 3 21 PlS- Sun Time AiM 7 pan. 6 5 4 93 10 11 2I 12 Pl- Sun Time AM -* l 5 aan. 6 7 8 9 10 11 12 67 p.m. 5 4 3 21 Nw,, NsWw, NE SE 8 100 100 100 100 100 95 95 90 100. 90 90 90 100 95 90 90 100 95 85 90 100 95 95 95 100 100 95 95 100 100 100 100 N, NE, E, SE SW Ttpe IV Pattebn NW` .NsWw' NE E SE 55 55 55 55 55 55 55 55 N, NE, E; SE NW SW s Type V Pattebn N, NW, W. SW NE E SE 8 60 60 60 60 60 60 60 60 35 35 30 60 35 35 30 60 35 50 40 65 35 50 60 60 80 90* 90 60, 70 105 105 90* 60 80 110 105" 60 60 85 115* N, NW, j W,8W NE E SE s 70 70 70 70. 70 70 70 70 70 65 65 65 . 65 70-- -70 70 70 65 60 60 65 70 70 70 70 70 65 65 70 75 80 75 70 70 70 70 65 65 75 90 N. NE, E, SE NW W SW S Type IVA Pattern N, NW, w. SW NE E SE ' S 55 55 55 55 55 5 55 55 n, ne; E,S$ 45 35 30 55 35 35 30 55 35 45 40 45 35 55 45 50 55 65 85 65 90 50 60 55 70 105 95 55 55 100 115 NW W SW S Designation of Block Type II--Semi-Light Diffusing III--Light Diffusing IV--Light Diffusing IVA--Light Diffusing V--Light Directing N, NE, E, SE NW W SW S * Reduce by 30% lor 30 deg N letitude only. Table 23. Approximate Corrections to Tables 14 and 21 for Deviations from Indoor and Outdoor Design Temperatures For each degree the design room temperature exceeds 80 F, subtract correction. For each degree the design outdoor dry-bulb temperature exceeds 95 F, add correction. Apply these corrections to each value in Table H or Table SI. Glass Ttpe Single Flat or Rolled Figured Glass Double Flat Glass and Glass Block Correction Btu peb (hb) (sq ft) 1.0 0.5 Cooling Load 295 the corresponding Table 14 values. The total instantaneous heat gain is the sum of the gain due to transmitted solar radiation and the gain by convection and radiation. The values given in Tables 17 and 18 are based upon an A.S.H.V.E. research paper23 to which the reader is directed for additional data. The values in Tables 17 and 18 may be used with fair precision for other pat terns of similar transmittance and surface characteristics. For example, the data for hammered glass may be used for glass having shallow, closelyspaced ribs or for glass having small, closely-spaced circular indentations. Because some patterns have distinct orientation properties, no attempt has been made to give values for non-vertical glass. Design Tables for Glass Block Walls Tables 20 and 21 give design values of instantaneous rates of heat gain for sunlit' walls of Type I pattern 8-in. hollow, glass .block for a solar de clination of 18 deg (see Table 19 for description of block patterns). These tables are based upon the solar intensity values for a clear atmosphere as given in Table 4. For solar energy transmittance data the reader is referred to reference 21. Table 20 presents values of transmitted direct and diffuse solar radiation, while Table 21 gives values of instantaneous rates of heat gain by convection and radiation from the wall. The latter values are for an indoor temperature of 80 F and a 95 F maximum dry-bulb temperature, as indicated in the table, and are based upon experimentallydetermined values of solar energy absorption and temperature difference between the two faces. Because the exact dependence of the latter on weather conditions has not been determined, the values of convection and radiation gain cannot be regarded as exact for the assumed design con ditions. Indoor and outdoor convection and radiation heat transfer data are the same as those used'for common window glass. Table 23 gives cor rections to be applied for other design temperatures. To obtain transmitted direct and diffuse solar radiation for other types of 8-in. block, the Table 20 values are multiplied by the approximate per centages given in Table 22. Note that corrections are the same for all latitudes, and that they vary only on the surfaces exposed to the direct sun. The convection and radiation gain values for all blocks are so nearly the same that a single table suffices. Note, however, that corrections must be made for certain hours for east and west facing walls of some patterns. Example tO: Find , the total instantaneous heat gain through aa east wall of 8-in. hollow glass block of Type V pattern at 8 a.m. and 50 deg north latitude. The design temperatures are 80 F indoors and 95 F maximum outdoor dry-bulb, clear atmosphere. Solution: The gain due to transmitted solar radiation is found from Table 20 for Type I pattern. The factor for Type V is found from Table 22. The convection and radiation gain is found from Table 21 (note the footnote). The total instantaneous heat gain is, from Equation 2a, ? = 86 X 0.65 + 26 X 1.4 = 92.3 Btu per (hr)(sq ft). Effect of Deviations from Design Conditions If the indoor temperature differs from 80 F, or the design outdoor drybulb temperature differs from 95 F, corrections can be made to the convec tion and radiation gain values for flat glass, rolled figured glass, and glass block according to the schedule in Table 23. The effect of the humid industrial type atmosphere is to cause a con-