Exhibitors Herald (1927)

EXHIBITORS HERALD April 16, 1927 Original Design Data for Theatre A ir Cooling By S. L. Goodwin Air Conditioning Engineer, Office of Thos. W. Lamb, Architect, New York 37 New Air conditioning in theatres is one of the larg. est fields existing today for inventive genius and for the development of apparatus and appliances for this special application. Three or four years ago the theatre owners in general did not know or appreciate the advantages of having their houses as comfortable in the dog days of summer as in the extreme weather of the coldest days in winter. As a result, empty — or partially empty — theatres during the summer months were accepted as a natural handicap under which all theatres were forced to operate. Some ran at a loss, others closed altogether. Now, all this is changed. Audiences and capacity houses are no longer dependent on the vagaries of the summer temperatures, and on the hottest nights many theatre patrons hasten to the nearest showhouse to cool off. It is interesting to trace the development in this particular field, going back a decade or so, when the idea had its inception, and following on up to the time when air cooling became generally recognized as a sine qua non of theatre construction. About ten years ago the manager of Orleans theatre told the writer that the installation of two large disc cooling fans had resulted in netting him a profit of $1,500 a week during the five summer months. Disc fans for summer use, with a combined capacity of 300,000 C. F. M. for a house of 3,000 seating capacity, was the first step in the direction of utilizing theatre plants costing from half a million to a million and a half of dollars for twelve months during every year. Next, the centrifugal fan was tried, and the Tivoli theatre in Washington installed centrifugal fans displacing 450,000 C. F. M. and giving a velocity of 200 F. P. M. air movement over every seat in the house. This is accomplished by injecting all the fresh air in the front of the auditorium ceiling and exhausting all the air from the rear of the gallery and orchestra so as to produce an air flow of the velocity stated. The loss of income if a playhouse is closed four or five months of the year on account of the hot weather — or is run practically empty if it is kept open — makes the universal use of refrigeration an actual economic necessity. As cooling plants become cheaper in their initial cost and their subsequent operation, refrigerated air conditioning, no doubt, will be extended to the smaller suburban houses. Another thing the use of refrigerated air in theatre work has done is to establish a milestone in theatre ventilation, owing to the fact that, in order to operate at all satisfactorily, only the very best of first-class apparatus can be used. In order to secure proper results in planning theatre installations, the engineer must in the beginning defi nitely understand his objective. What is he planning to do? What is he to accomplish? First of all, he must contemplate cooling a theatre during the summer months when the thermometer ranges from 70° F. to 100° F. dry bulb). In the second place, he must do this with a varying degree of humidity. In the third place, he must be able to do this equally well with audiences running from a few score to several thousands. As nearly as possible, these ’varying factors should be controlled by automatic instruments. The engineer must also bear in mind that the dry-bulb temperature is not, by any means, a safe guide for comfort. The writer remembers an instance where, on an opening night in a remodeled playhouse, he was walking through the balcony with the manager, who commented on the comfortable temperature in the building. A dry-bulb thermometer indicated 75° F. but there was no air washer in this installation and the outside temperature was about 20° F., giving a relative humidity in the theatre of about 12%. Nor is the wet-bulb temperature any more certain. During midsummer the body becomes more or less accustomed to high temperatures and a S. L. Goodwin Mr. Goodwin, air conditioning engineer and connected with the offices of Thos. W. Lamb, architect. New York City, is recognized as an authority on air conditioning and refrigeration. This article and others to follow by Mr. Goodwin are published through the courtesy of The Heating and Ventilating Magazine. Mr. Goodwin, in these articles contributes important data on the technical and mechanical phases of ventilation, heating and cooling. T'ab/e I Body He a / B.T (7. 3. OOO S X 3SO B 3, OSQ OOO Jr’oof. , , , O.S7f /OO-O X X x^S°</ 79.600 ^ /i C Wo/Zs //4> -o" X 60 '-o " X X^jidesxasst x .dS°d_ _exd, OOO H/e cZr/c/ZyL ZOO, OOO hZ X d.'d/S^. ITT ■ 67, 900 — BOBB/, HHBT’ 7,033 Zn 3ummer, per />x ^.Z,30Z , 700 TodZe d CLZ. HB y>er HZn. C.HM. Z, JOZ, 700 B. TU. x^dCCir Bf. per B.BZ/. ) OOO OO f B/nuZes per Hour) 67.000 C.HH. per Herjon Zn Bud/Zor _ _ _ , » ium AJ//ohz/no /-(/ '‘Y?ar>^e‘ 3.000 fSeoZs) oZ TeYprruZure . . . .3 9 TaSJe J /i/r AfoAe Up 90° S’ ~ SS "A Se/ //um/d/yy= 6./J Srai/ys per Ca S/t S9 "B ZOOZ HeZ HumZddy^ S.S6 " Wa/er APe/noved /rom Sres/^ S 7 " Supp/y Son Copoc/fy CBM. j3mo// j[joJ}6y ( was/edj ZO, OOO SAea/re ffi/rcBA a/r moAe-op, no/ rec/rca/o/ed)./ S, OOO At ud/Zor/urn freczrciz/a/cd o/r) _ 37 S, OOO TOTBJ, SLZPPBY /OO , OOO drop from 90° F. outside to 70° F. inside may be, and often is, too great a change for comfort. This is especially true after persons have become accustomed to heat such as in midsummer or early autumn. Complaints were made at one time that a certain refrigerated theatre was ‘damp as an ice box.” Investigation showed 70° F. temperature, with a relative humidity of 50%. The air was actually quite dry, but it was too cold, and a number of persons complained of catching colds in this theatre. As an experiment, the writer tried sitting in the balcony with an outside temperature of 90° F. and the theatre temperature at 78° F. For the first twenty minutes he felt distinctly chilly! To hold the temperature of a theatre at an even line of comfort, the engineer has two unit factors to consider: (a) a cubic foot of air, and (b) the allowable range of temperature of that air. The maximum range of temperature is about 14° F. ; that is to say, if the air leaves the cooler at 66° F. and returns at 80° F., the extreme allowable variation of heat is being utilized. One B. T. U. will raise 1 cu. ft. of air 55° F. Therefore, with a maximum range of 14°, 1 cu. ft. of air 14 will remove — B. T. U., or 0.254 55 B. T. U. If a greater temperature difference is allowed there will be a danger of draughts. From this it can be seen that it requires almost 4 cu. ft. of air displacement to remove a single B. T. U. Now, if we figure the total heat supplied to the auditorium in B. T. U.