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CHAPTER 13 269?\6J Table 22. Instantaneous Rates op Heat Gain Due to Transmitted Direct . and Djppcse Solar Radiation bp Unshaded Walls op 8-in Hollow Glass ` Block op'TypesII, III, IV; TVA. and V Patterns Multiply the Table 20 Values for Type I by These Percentage Factors For Clear Atmospheres and 18 Deg Declination, North (August 1) For SO, 40, and SO Deg North Latitude Note: To obtain total instantaneous heat gain add adjusted Table 20 values to the Ti aUUbfcleO SDIi vvavmluwews.. V s'7 Instantaneous Heat Gate? Bus to Transmitted Solar Radiation as a Percentage op Typei Patters -ftV 1 Type II Pattern | Type ID Pattern ! SunTxmb E SE S N.NW, w.sw NE E SE & ft 100 05 00 00 85 05 05 100 100 00 90 90 00 93 05 100 100 too 100 19000 95 100 100 70 70 70 70 70 70 70 70 70 70 65 70 60 65 60 65 65 70 70 75 70 80 1.70 75 -- ft W 6W s N.NE, E,SE W sw Sun Tim 7 p.m. 6 6 4 3 21 T PM - Sun Time AM < l 56 aJD. 7 . 1890 n 12 705 p.m. 4 3 2l Ttp IV Pattern N.NW, w. sw NE E 55 55 55 55 55 55 55 55 45 35 45 45 45 35 35 30 50 55 55 25 35 45 55 55 N. NE. E, SE NW W Type V Pattern NE E SE 60 60 60 60 60 GO 60 60 35 35 35 50 80 70 60 60 35 35 40 65 00 105 80 60 30 30 35 50 00 105 no 85 60 60 60 60 60 00" 105" 115" I N, NE, E, SE NW W sw Designation of Block Type II-~Seim-Light Diffusing III--Light Diffusing IV--Light Diffusing IVA--Light Diffusing V---Light Directing * Reduce by 30% lor 30 dec H itudeonly. _______ 'ft T*y Table 23. Approximate Corrections to Tables 14 and, 21 fob DxnjgapHSiif prom Indoor and Outdoor Design Temperatures For each degree the design room temperature exceeds 80 F, subtract correction. 'i-cl.:'- each degree the design outdoor dry-bulb temperature exceeds OS F, add correction. these corrections to each value in Table 14 or Table 21. ifif i ---------------------------------- :-------.-------------------------- :------.------------------- !------------ --------------------------- :----------------------------- ---------------- ' Glass Type oineie Flat or Rolled Figured Glass Double Flat Glass and Glass Block Cooling Load 297 the corresponding Table 14 values.- The total instantaneous heat gain ja the sum of the gain due to; transmitted solar. radiation, and: the gain by convection and radiation. . , , , - . ,! . ;. The values given in Tables 17 an:d 18; are based,upon-an.A.S.H.YiE, research paper2? to which the readerlis.dipected for! additional data. The values in Tables 17 and 18 may. be used with fairiprecisipn for ;Othei\patr tems of ,similar transmittance and surface.characteristics. , For. example, the data for hammered glass may be used for glass having shallow, closely- spaced 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-yertical glass. Design Tables for Glass Block Walls Tables 20 and 21 give design values of.instantaneous irates .of heat gain for sunlit walls of Type 1 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 and1 temperature difference between the two faces. Because -the exact, dependence of the latter on weather conditions has not been determined,: the1values 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 t0: Find the, total instantaneous ,heat gain through an east wall of -in. hollow glass block of Type V pattern at8 a'.m. and SO deg north latitude. The design temperatures are 80 F indoors and95 F maximum Outdoor dry-bulb, clear atmosphere. , Solution: The gain due to transmitted solar radiation is found from Table 20 r,*yP? I pattern. The faetor for Type' V is found from Table 22. . The convection na radiation gain is found from Table 21 (note, thefootnote). The total instantaneous heat gain is, from Equation 2a, q = 86 X 0.65 + 26 X 1.4 = 92.3 Btu per (hr)(sq ft). Effect of Deviations from Design Conditions K the indoor temperature differs from 80 Fj,or the design outdoor drybum temperature differs from'95 F, corrections can be made to the convechon and radiation gain values for flat glass, rolled figured glass, Mid glass block according to the schedule in Table 23. The effect of the humid industrial type atmosphere is to cause a con-