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Home My WebLink AboutCorrespondence and text of The Installation of Attic Fans 1941 AMERICA\ SOCIETY OF HEATING AND VENTILATING ENGINEERS NEW YORK, N.Y. 51 QJaa on c'lve#uce �e7ephene, AS4 4 -0291 August 16, 1940 File 2 -99 Prof. W. H. Badgett Texas Engineering Experiment Station Agricultural 6: Mechanical College of Texas College Station, Texas My dear l'rof. . Badgett: Your August 15 letter has been received together with a copy of a paper which you presented in Houston last spring under the auspices of the Houston Lighting and Power Co. entitled The Installation of Attic Pans. The Meetings Committee believes that a discussion of cooling by the use of attic fans would be an appropriate subject for discussion at the Houston Meeting. If comparative data could be given on the installation and operation of systems which supplied outside air to all rooms and systems which brought the air in and exhausted it through the attic it would be of interest. Inquiry has been made about systems that would supply filtered air through ducts or grilles to the various parts of the house and those which draw in air through open windows and exhaust it through the attic. No doubt, some of the data that you pre- sented in Bulletin 152 could be used in such a paper. Our members would also be interested in the area in which attic ventilation could be used, as well as operating methods and costs. Papers given before the Society should in the opinion of the Publication Committee give research, design or operating data which would be of practical help to the engineer. Due to the necessity of having the manu- OFFICERS COUNCIL F. E. GIESECKE, PRESIDENT, College Station, Tex. FOR THREE YEARS FOR TWO YEARS FOR ONE YEAR W. L. FLEISHER, IST vlcE- PRES•, New York, N. Y. J. F. COLLINS, JR., Pittsburgh, Pa. E. K. CAMPBELL, Kansas City, Mo. N. D. ADAMS, Rochester, Minn. E. O. EASTWOOD, 2ND VICE - PRES., Seattle, Wash. E. N. McDONNELL, Chicago, III. S. H. DOWNS, Kalamazoo, Mich. A. P. KRATZ, Urbana, Ili. M. F. BLANKIN, TREASURER, Philadelphia, Pa. T. H. URDAHL, Washington, D. C. A. J. OPENER, New York, N. Y. J. F. McINTIRE, Detroit, Mich. J. H. WALKER, Detroit, Mich. A. V. HUTCHINSON, SECRETARY, New York, N. Y. C. -E. A. WINSLOW, New Haven, Conn. G. L. TUVE, Cleveland, 0. G. L. WIGGS, Montreal, Canada W.H.B. - 8/16 /40 script for review by the Publication Committee within the next two weeks I will be interested in knowing whether you have data availalle for a paperalong the lines mentioned. Very truly yours, SEC R ET AR Y AVH /DMM c.c. F. E. Giesecke `--- 1 THE INSTALLATION OF ATTIC FANS By W. H. Badgett Presented at a Meeting of Attic Fan Manufacturers, Dealers, Salesmen, and Architects in Houston Texas, June 17, 1940 and Sponsored by the Houston Light and Power Company. I. Introduction. I assume that each and every one of you in the attic ventilation business are in it to make money. Also that you expect to be in the business next year and for many years to come. One way to assure yourself of making money and prospering with each succeeding year is to make a reasonable profit on each sale you make and to make the sale and the installation so definitely right that there will be no need for call backs and adjustments to eat up the profit. If each sale is not properly made and installed you might wind up at the end of the year with a heck of a lot of business -- but with a headache and no profit for all your worries. Speaking of call backs and adjustments brings this thought to mind. A number of fans were purchased last year by contractors for instal- lation in the many new homes they were building. They shopped around for price, and goodness knows I don't blame anyone for trying to make a good buy at any time, but if you are selling the contractor trade, sell him what he needs to do a good job. If the fan is to go in a 10,000 cubic foot home, don't let the contractor put in a smaller one if you can possibly help it. If a smaller fan does go in, you have lost that added profit that you might have made from the sale of a larger fan. The person who purchased the house is not satisfied because to get adequate attic ventilation in Houston one has to have an air change about once a minute. With such a change a person can feel the air movement, can observe the fluttering of curtains and drapes. Where a smaller 2 sized fan is installed, the owner cannot feel the air movement, cannot see the curtains flutter and consequently says his attic ventilation is not satisfactory. As word -of -mouth can make sales, word -of -mouth can break sales. Even if the proper size fan is sold and is not installed properly, the results are the same. You have a dissatisfied user who will tell his neighbor that he has an "XYZ" brand fan and that it is not satisfactory. You who sold the fan are the one who gets the blame, you are the one who gets the service calls, you are the one who gets sales resistance on other sales and you are not the one to blame. So, to insure yourself of freedom from such - complaints, see that your contractor gets the proper size fan and that he thoroughly understands its installation and you will see that your business profits and prospers. • One more thing while on this subject: I have never heard of a fan being sold that was too large for the job intended, but I have heard of some fans being sold that were too small for the job to be done. I have noticed that some manufacturers are now offering fans with two speed motors. With a two speed job a customer has greater flexibility. They have that high speed for extreme hot nights and then, of course, low speed when the requirements are not so great. Two speed jobs cost a little more, they are worth a little more and, of course, it gives you an opportunity to make a little more profit. II. Instal ion Costs. he ow cost of n otalling a i4 ventilation or home c oling es it by fa the eape7 meth•d now : ailabl= for re ief om r he . ihis cos of course, ries with •e size of the se and a type of construe •n, 3 b t the av =rag= home can now e uipped adequately or the cost f a short amily acation, • the = xpense of addia porch, or w electri efrige- at. . III. Operation Costs. As time goes on we are continuing to get more accurate figures on operating costs. As you know, most power rates are based on a sliding scale depending upon the number of kilowatt -hours used each month. Statistics indicate that the average home owner who has an attic ventilating system already has in use a number of electrical appliances such as a radio, refri- gerator, vacuum cleaner, washing machine, and such, and therefore the add- itional power used by an attic fan falls in the lowest rate bracket. I am sure you will be interested to know that the Dallas Power and Light Company set test meters for a season's run on 55 fans. These tests e - rr glide 1 _ were made on 30 ", 36 ", 42 ", 48" and 54" fans. The average c was '"-"'- 320 kilowatt -hours per season. Based on 3i per kilowatt -hour, it makes an average of 49.60 per season which, of course, you can break down into monthly operating cost of about 41.60 per month for six months. Certainly attic fans are economical to operate when one considers the many advantages that it brings to the home. You can safely quote your operating cost of an attic fan at less than 12¢ per hour. (Show slide of cost table) IV. Selecting the Proper Size Fan. One of the most common mistakes made in installing an attic venti- lating system is the selection of a fan too small for the house to be cooled. Satisfactory cooling requires many times the volume of moving air needed for simple ventilation. As I said before, experience gained in the past few 4 years indicates that adequate fan capacity to give a complete air change throughout the entire house, except closets and pantries, of at least once a minute will ordinarily insure satisfactory results in Houston and the Gulf coast region. For daytime and early evening operation, and during periods of exceptionally hot weather, it is often desirable to secure more air movement than produced by one change per minute. This may be accomplished by closing off those parts of the house not being used at the time and directing all air moved by the fan through the occupied portion of the house. In some cases it is always necessary to ventilate practically the entire house at one time. This is particularly true of small houses, apart- ments, and tourist courts. In these cases, fans with a capacity greater than one air change per minute -- about 12 to 2 air changes per minute -- are often desirable. Sometimes larger fans are required because of a poor intake grille location, high ceilings, rambling house construction, or casement windows. However, where it is possible and satisfactory to ventilate about one -half of the house at a time, one air change per minute will be found adequate for maximum requirements even in the hottest weather. Often it is advantageous, and in fact many times it is necessary, because of structural difficulties, to use two small fans instead of one large unit. This makes a more flexible installation without any sacrifice of efficiency. Such installations are particularly adaptable to low attics where there is insufficent height for a single fan of adequate capacity. When two or more fans are used in parallel in a single installation, cross- suction from one fan to the other must be prevented. This may be accomplished by the use of automatic doors. on the exhaust side of the suction box or 5 automatic ceiling shutters. Two or more fans in the same suction box should also be separated from each other by a fiber board partition or baffle. V. Methods of Installation. The location of the fan will depend first upon the position of the ceiling grille. The ideal location of the ceiling grille and fan unit is °L'i 0 • - -- in the ceiling of a central hall, thus affording ready distribution and flexible control of air movement through- out the entire house. It is preferable that the fan be placed over or near a partition wall or other solid support in order to prevent undue sagging of the ceiling and excessive vibration. An excellent location is over a closet. The fan should never be less than three feet from the nearest side of the ceiling grille. If a fan is located too close to the grille opening, air and fan noises may prove objectionable. The farther back from the opening the fan is located, ordinarily the quieter the installation. However, for greatest economy, it is usually satisfactory to place the fan one fan diameter from the nearest side of the grille. e ed less t If it can be avoided, never locate the fan facing toward an attic window or louver opening. This prevents light from shining through the fan into the vent box and flickering in the room below. The exhaust side of the fan should be free from obstructions; that is, the fan should not blow directly against any object such as the walls, the roof, or a chimney. To do so would build up a back pressure which would reduce the efficiency of the fan, 6 thus increasing the cost of operation, and probably would increase the noise level to objectionable proportions. The fan should be so placed in the attic that the air will be circulated as much as possible before it escapes through the exhaust openings. That is, if the fan is faced away from the exhaust opening, it will more completely sweep the hot, dead air.from even the remote corners of the attic. VI. Suction Boxes. Different structural conditions encountered in homes do not permit a set rule for suction box construction. It is most practical to work out details of construction for each particular job. However, a few general principles should be observed in building a suction box. The cross section of the box should never be less than the area of the fan, for if air moves through the box at too high a velocity it will produce objectionable noises as well as reduce the efficiency of the fan due to resistance. All framing members should be placed on the outside of the box, for if placed inside, they would retard the air movement, thus increasing resistance to air flow and creating disturbing cross- or eddy - currents. A sound absorbing material such as rigid insulating board is recommended for suction box walls. The ceiling grille opening, whether of the automatic closing type g (fides or of the open type, should be covered by a manually operated trap door, / 3 hinged into the back or floor of the suction box as illustrated in the next � slide. It is not satisfactory to use this door both as the back of the box and also as the trap door. However, this cover may be used both as a fire door and as a closing for the ceiling grille in the winter. For the latter type of operation, the cover may be lowered by means of a rope and pulley from a closet on the floor below. For use as a fire door, a 135 to 150 F fusible link should be inserted in the pull cord so that the door will close 7 automatically in the event of a fire inside the house. Either type of installation should be equipped with an automatic shut -off or a safety switch which stops the motor when the trap door is lowered. The suction box should be provided with a service access door. The suction box should be the length of the ceiling grille plus not less than one diameter of the fan. Its height and width are governed by the size of the frame carrying the fan assembly. Should the ceiling grille be wider than the fan assembly, the suction box should be made the width of the grille. For maximum efficiency the box should be as nearly airtight as possible, and all joints, cracks, and corners should be sealed with heavy gummed kraft paper. If light reflections pass through the ceiling grille, the interior of the sactian box should be painted a dull black. VII. Ceiling Grilles. In planning ceiling grilles, two important points should be kept in mind. If at all possible, the grille should be located in a central hall so that air can be readily pulled from any or all of the rooms as desired. The effective area of the grille must never be less than the area of the fan. For homes and other locations where quiet operation is desired or is essential, the net grille area should be of sufficient size to assure a grille velocity of not more than 750 feet per. minute. This is net area only and the total grille must be larger depending upon the type of grille and whether or not it is covered with screen. If space permits, even lower velocities are desirable in order that the installation may be as quiet as possible. A velocity through the grille of between 500 and 750 feet per minute is considered good practice. 8 Perhaps the most common types of grilles used are the wooden egg - VI de r crate type and the expanded metal grille made of 3/4" No. 16 guage Shelf -X mash. Wooden grilles constructed of 1/4" x 1 -1/4" white pine strips notched E (i '6, 3" on centers and mounted with the proper trim will harmonize with the decor- F ative plan of any home. This type of grille has a net free area opening or efficiency of 80 per cent. The expanded metal grille is proving very popular, because it is less expensive and easy to work with, and when painted and properly trimmed, also makes an attractive installation. This 3/4" No. 16 Shelf -X metal lath has a net free area or efficiency of 63 per cent. Another type of ceiling opening used extensively is the automatic ceiling shutter or grille, which opens when the fan is started and closes when the fan is not is motion. These are usually constructed of lightweight aluminum or steel vanes balanced so that a very small suction is required for their operation. For quietness, the overlapping lip of the vanes should be faced with a thin felt strip. The hinge pins of the vanes should be cleaned at least once a season, or oftener if required, and oiled with a light weight machine oil so that they will operate quietly and with the least possible resistance. An accumulation of lint and dust, if not period- ically removed, may retard the operation of the automatic shutters and thus reduce the efficiency of the fan. Automatic grilles or ceiling shutters prevent mosquitoes and flies Prop entering the house through the attic and eliminate hot back drafts when 9 the fan is not in operation. Automatic ceiling shutters or double automatic doors on the exhaust side of the fan are necessary in multiple apartment houses where each apartment uses a separate fan in the same attic. This prevents fans from blowing air from one apartment of the attic into another apartment in which the fan is not being operated. Ordinarily automatic grilles prove more satisfactory than automatic doors. VIII. Attic Exhaust Openings. Attic exhaust openings may be any one of many possible kinds or yi /ciPS may be a combination of several types: such as existing attic windows, either 45 / existing or specially constructed louver openings at gable ends or in dormers, 10 / metal roof ventilators, pent houses, openings under the eaves between rafters, / ' or exhaust grilles in the ceiling of a porch. t It is of vital importance for successful fan operation to have / adequate exhaust openings in the attic; and, for the best performance these should have an area of sufficient size to produce a face velocity of not MOM jnms than 750 FPM. Because of the obstruction to air flow caused by the slats or louvers, which reduce the louver efficiency to less than 100 percent, the total gross area of the louver will be considerably more than the net free area required. F.1 de' TheSperformance curves illustrate the necessity of having both exhaust openings and ceiling grilles of adequate size. These ✓ curves are plotted from data secured from rating tests in the Fan Testing Laboratory of the A. & M. College, on a 42 -inch attic ventilating fan at a speed of 304 RPM, and equipped with a 1/3 HP motor. 10 From these curves it is seen that at free delivery, or zero static pressure, the fan delivers 10,250 CFM while the motor requires a power input of 360 watts. Now, if either or both the exhaust opening or ceiling grille should be so inadequate for the installation that the static pressure or resistance against which the fan operates is 0.12 inches of water, slightly under one - eighth inch, we see that the fan capacity decreases from 10,250 CFM at zero static pressure to only 5,000 CFM at 0.12 inches of water -- a 50 per cent decrease in air delivery. At the same time the power input to the fan motor has increased from 360 watts at zero static pressure to 550 watts at 0.12 inches resistance -- a 53 per cent increase in power consumption. The full load torque for the one -third horsepower motor with which this fan is equipped is approximately 365 watts, and with a 25 per cent allowable overload the power input could safely reach 460 watts. However, the power input required for this fan at 0.12 inch resistance is 550 watts, which exceeds by 50 per cent the full load torque. From these curves it may be seen that as the static pressure or resistance increases from zero or free delivery, the fan capacity decreases, and at the same time the power required to operate the fan motor increases. Therefore, if either grille or exhaust opening is of insufficient size, or if an obstruction in the air stream in front of the fan is encountered, maximum efficiency will not be obtained in the fan's operation, and it is even possible that the motor may be overloaded so that permanent - A damage results. The porch vent is increasing rapidly"T popul ity �rg� ( ( ;4_4) ( 7 11 first choice by many who install attic fans. If it can be used, it is ordi- narily the least expensive because it eliminates the necessity of costly work in enlarging gable louvers or constructing dormers. With the porch ceiling exhaust, there is no possibility of driving rains blowing into the attic or disastrous leaks about the flashing. However, when porch vents are used it is necessary during fan operation to close porch windows and doors; otherwise the hot attic air from the vent will be drawn back into the house. For several minutes after the fan in such an installation is turned on, the air expelled from the ceiling exhaust will be unpleasantly warm. In many sections of the country, such as this is, it is essential that exhaust openings be screened to prevent mosquitoes and flies from enter- ing the house. When this is done, the screen area should be at least double that of the exhaust opening so that resistance to air flow will be reduced to a minimum. This increased area is obtained by framing out from the exhaust opening into the attic. Even these screens gradually clog up with lint and dust, and they should be inspected and cleaned once a season or oftener, if necessary. IX. Noise Elimination. The quietness of an attic fan installation will depend to a great extent upon the inherent characteristics of the fan, but care in its proper installation will go far in providing quiet operation and consequently a more satisfactory fan installation. Regardless of how well balanced a fan is, it should be isolated from the attic floor by being mounted on vibration dampeners, sponge rubber, or felt cushions, even though vibration dampners 12 are used in the construction of the fan. The fan motor should be mounted so that vibration and sound transmission are eliminated. The fan housing should be isolated from the suction box by means of a strip of eight or ten ounce canvas so that vibrations or noises will not be transmitted directly to the box and subse- quently to the house structure. Caution should be exercised in wiring the fan to provide flexible or non- metalic connections to the motor to prevent sound transmission. Most attic fans operating under pressure or resistance become noisy. Resistance is determined largely by the size of the intake opening to the suction box and the exhaust opening from the attic, and therefore, for quiet operation, it is essential that adequate grille and attic discharge openings be provided. As previously mentioned, the fan should never be placed closer than one fan diameter to the nearest edge of the ceiling grille, and the fan discharge should never blow directly against any obstruction such as a chimney, gable wall, or roof. If, because of the nature of the attic, it is impossible to locate the fan so that it will not discharge 3awe� directly against such an obstruction, it should be at least five feet from the nearest obstruction. Quietest results are secured with the suction box constructed of rigid fiber board having sound absorptive qualities. X. Wiring Recommendations. The services of licensed electricians should be used in every installation where they are available. All wiring ordinances and fire under- writers regulations should be complied with. The fan motor should be i '• ' 13 connected to a circuit of adequate size to carry the increased load. If an existing circuit is not available, the motor should be placed on a separate circuit of not less than No. 12 wire. Fans with one -half horsepower and larger motors should invariably be placed on separate circuits of No. 12 wire or larger. The switch should be located as centrally and conveniently as possible. In a two -story house, and occasionally in other instances, it is desirable that two three -way switches be used so that the fan may be controlled from either floor. Some fan owners perfer that the switch be placed near the owner's bed. However, usually the most convenient location is in a centrally located hall. In order to avoid confusion with light switches, the fan switche, should be placed at least twelve or eighteen inches above the customary height employed for light switches. A good automatic time switch makes the installation more satisfaot ry. 4 , In conclusion, I b lieve that without fail you should explain to your customer just what to expect of an attic fan system. They should know that such a system is not to be considered as a substitute for complete air conditioning, but that it is a practical and inexpensive means of securing relief from summer heat. And by all means, do not fail to explain how to operate the system to secure the desired results -- even though it seems so obvious and ^simple to you. I 1 �. , / 6 ,r... AM E RICAN ARTISAN WARM AIR HEATING NG AIR C • KEEIIEY PUBLISHInG COMM - 1Y 6 f1ORTH t11ICHIGAn AVEf1UE CHICAGO March 13, 1941. Mr. W. H. Badgett, Research Associate, Gibb Gilchrist, Director, Texas Engineering 'experiment Station, College Station, Texas. Dear Mr. Badgett: I have studied with considerable interest your bulletin "Installa- tion and Use of Attic Fans." In American Artisan during the past five years or since the Engi- neering Experiment Station of the University of Illinois first reported on attic fans, we have published each summer a number of articles covering the engineering, installation, design, sales, advertising and general promotion of attic fans throughout the country. We feel that we have pretty well covered t "e subject, but each year we start in again because there are newcomers who seem to require all the information previously covered. Accordingly, we would like to publish a series of perhaps four or five fairly short articles on attic fan installation, beginning with April and ending in the middle of the summer. We would like to use the chapters in your bulletin for this purpose and will, of course, give proper credit in each article to the source. May we have permission to so use your bulletin and please let us know if you ;Jant page n_ roofs submitted each month prior to publication, or only page proofs where we deviate in sane way from the text2 "re also have in mind including in this series some tables from the Bulletin of the Houston Light & Power Company. These tables cover such facts as "Minimum Recommended Exhaust Openings for al Types of :Exhausts," and "Installations of Attic Fans on Flat Roof Houses" and "Suggested Air Changes in Commercial Ven- tilation." These tables and data will be presented supplemen- tary to the articles from your Bulletin, but would probably be referred to in an editorial Foreword, and will not be inserted in the text from your Bulletin." Since-ely yours, AMERICAN ARTISAN 1 rtt 7 ° _ e • JO's :k ` �„ . J 1: Wilder, Editor. ‘,, •, • .-„. _ April 15, 1941 Mr. J.D. Wilder, Mitor American Artisan 6 North -ichigan Avenue Chicago, Illinois Dear Mr, Wilder: Your letter of March 33 re . , and use of attic t pub tie fans in the g permi salon to lish parts o eon nt of T 11 o rrxy bulletin on i the L . American A rt am now on leave of a the I ted States, just come to my attention. wi the Aral of the romptly. the A and M College tour of activ: a7d1 :ome reason your letter was not forwarded to Me p I would indeed be very credit of course &sine with proper c er ry your meg.. not neces .-. as you have outlined in yo happy to have you use my bulletin being given to each A rt f h text, nu lished each month be furnished from the tele as to its source. It is n that page proof: as . licat ion, exeeP- in ea th es articles appear w in which e prior to pub. copy of the American Artisan b ses where deviations ire mode Your sending be greatly appreciated. Please addres them Ile a co will g f this letter, at the heading 0 s as shown a It is hoped that NY delayed reply to your letter has not I am publishing i these articles, and inconvenienced your plans t f , or p w u ith great interest. looking forward to seeing nem Very sincerely yours, WHB a vrh, W i Infantry Captain, ri li • BADD p SrT -4 ,,,-; , -, - "- -= , -*1- 0 ,' -. „-:...,:e,kli.st - , .T.,,,..' , 7 , 4-, ..: ‘ ..F ' v: :•-f, .,..,,, A: , , i ',.....4:i4c- ?„,i, , .,, ‘, ,; , ,,,,.; 7ioti '''''''''' ' ", ,r,.,'` .,ji- ' -'' .,4p.o .,' - .;4,41‘;',..ts ,.t..i;tf:--i:-,,,,, ''. - - ,74', ,:::' .$0.47-,-1.!tli"1::??1.1,74 .1'11' 4:4-t' llgr441;,.,,,,,,,,,,,.,,,,,!.sz., ,,,,o,'F.1,1, ';')O, 'r. ..-'.'.' i'i'fie • ;,, .:;','1, y - lit, ' ,- 4 1 ... — . 11,- iiii, -,,- =' - ' - ' , ....)7,4-4 . '-', -t 4s `: -,, ,-. ,,, ': -,.. 4 ,, , - ; ,, ,v,„,f '4 „. ...,,,ive.440,s, ‘',1--: --°--#1.1 r h. 'i , - - ,,i,:lt: . • ,' - vg....,'„,?=' i. -..',..: I' "M- , ,le„,)vA-.'', VirliZ-N10, '," '.-"t -1.... 4 2 , ' ' ' ' . , .,, 4 „sdr-qt;A,-;,.. 0 r,t4, ,A, -'A 4 V,, ....i.,14 w 4 ."1 . 4',.., ,- ‘„' ' i*,,04 i 1/4.`A....7` ' iglIa° A„ "P"; ''''., ■i, ' "4"Pir ■44,:i2'N-Vc 7`4„,N,,,,,,,; O 4, - ' : *P 1 , 7 * i~"`:" ,:i 44,,,,v,,,z''rifit;,' 1 =4,4fer,r , 'lc 4 •:' ,. Lr ' 4. '?„, lU ICI II1/1E RSA IL , COMMIE INC Ii AN INTERNATIONAL TRADE MAGAZINE n1, R KO BUILDING • ROCKEF ELLER CENTER PUBLISHED BY D'AQUILA PUBLICATIONS, INC. N E W YO R K , U. S. A. CABLE ADDRESS: WORLDTRADE, NEW YORK April 24, 1941 air. W. H. Badgett, Research Assoc. Agricultural-aid-Mechanical College of Texas College Station, Texas Dear Sir: Our publication circulating in many of the tropical countries has prompted the idea that sometime I would like to schedule a story on attic fans. Consequently when reading a synopsis of your report in the April 16th issue of Air Conditioning & Refrigeration News, my urge to present such a story to our rea ers g as encouraged. By the way of explanation, UNIVERSAL COMMERCE is an export publication circulating throughout the world although I: must say that today our major circulation is to Central and South America. I am quite confident this is a subject that will capture the imagination of the thousands of importers we reach. In order to intelligently and comprehensively prepare this story I wonder if you would be kind enough to provide me with a copy of your bulletin "The Installation and Use of Attic Fans." Obviously, the necessary credit will be provided to you and the Agricultural and hdechanical College of Texas. Looking forward to your favorable response with keen interest, I am Very cordiall vo d s/ Oil) UNIVERSAL Co rriai'' '' NIC +a ( q. E. B. Heeseler Editor ebh;dk HITE- RODGERS `1''' ELECTRIC COMPANY 1209 CASS AVENUE • ST. LOUIS, MISSOURI June 20, 1941 Agricultural & Mechanical College of Texas Engineering Experimental Station College Station, Texas Gentlemen: Your series of articles entitled "The Installation and Use of Attic Fans" published in the American Artisan has been of great interest to us. We note, however, that thus far you have made no mention of controls as used with this type of installation other than the manual on -off switch, or the so- called timostat arrangement for continuous operation over a period of hours. We would appreciate this opportunity of introducing to you a full complement of controls for attic fan systems. The White- Rodgers Electric Company have designed a system of these controls with descriptive literature enclosed. This system of controls consists of a room thermostat properly located on the second floor of the home and a tiger relay. The timer relay consists of a clock which can be set for predetermined hours of fan operation with thermostatic control during this selected period, thus affording a completely automatic system. If, however, the system should require operation during the daytime, such as to remove smoke or odors, there is a manual switch in the thermostat to give such operation. You will note that in order to increase the ease in which these controls can be installed we have supplied a female plug installed in the top of the controller and, also, three feet of rubber covered cord with a male plug attached, so that mistaken wiring in the hook- up is completely eliminated The male plug from the fan motor is easily plugged into the female plug on the load side of the relay, while the male plug from the line can very easily be inserted in the closest convenient outlet. Thus, the wiring of this system of controls to the equipment is practically nil, with the excep- tion of running the low voltage wire from the controller to the thermostat. In this manner we eliminate the necessity of having an electrician installing the controls on the job, thus producing a saving in the installation cost of the unit and controls. This letter is being written with the thought in mind of stimulating sufficient interest to warrant your desire to have a set of controls of this nature for any future tests that you might run on attic WHITE-RODGERS ELECTRIC COMPANY 1208 CASS AVENUE • ST.LOOIS.MISSOONI -2- Agricultural & Mechanical College of Texas June 20, 1941 fan ventilating equipment. We would be pleased to send you a set of these controls upon your request. If any further information on this subject is desired, kindly do not hesitate to inform the writer. Yours very truly, dreelils.lectric Company I G.R.Gibson /LS Enclosures RORM IM 1 II Mit ( • (, # '.\0 '...<...". P . 1'1. . ... li .,,,.,, 1/ IP:. ,. ...2,....- - L_ - ..._,\ ,.....z...7_, li ..,-; ti, #p, - -- )It - geit„„„, ,,- - , 1 ..._. . , T ITAN ■ , w g\‘■,.. , .. „ .,, , \ - I • , . . / ) , al i 1 1111 1 .4;zi - '-: ' • . liSP' i / Ei . / / .-P. ITI ''' I _ - Err , 0 „r,,,,.!:, If --,':_.,./1 ,--11' 4$ .”. '... ..z. • Jr . ay. 0 ' --„ gv . ' div A $ / . ,,--------:: . i, .,...,..„ ...,...,-..:,,,;.:.4- 4 -.4_, '' . 1P- 110 ' • ''' ' ' ''' , 0 , 1 " ::':t -4 4; ; ',' 1 ::: " 1. • 1 - . St: . . i 6 '' ' , . Illi cilealati Sigootottell. coot/ 94 *04t44, With . . - 0 • WHITFINNIIIII 1 I 1 -w 11 1 El Fins CILINTRIlLa A fahe 6 . 41 , 1 , 14 o y. f- __., ..,,,... . will* ..............,_ .... , __ 066,,,, /04. 1 ,..t . ,.. _ .._ .... ,, i 1 • t , ,e------- . a __,.... __ * ( \ , ,.„,„ 111111 ,....... ,., J 4 14 1011111 11 ■ I 1� n 1 ‘1111111 I 1 IL WHITE - RODGERS , J � III Il ATTIC VENTILATOR CONTROL , , ` .i ) i 1 "I." � \ III \�i � 9 .\ 111' '' , '. '' `.... M 114 ! O I /� \ 1 - xi% , ‘qP COMPLETELY • You'll sleep in cool comfort all summer long If it turns cold during the night you need not when you install an Attic Ventilating Fan be on hand to turn off the fan switch. The equipped with dependable White - Rodgers White- Rodgers Thermostat does it automatic - Automatic Controls. ally when the desired temperature is reached, These controls when used with your Attic Fan, thus reducing electric current consumption. quickly and automatically draw hot daytime Each morning, to retain the cool night air in air from your home at night, allowing the whole family to sleep in the cool comfort of your home for greater daytime comfort, the evening breezes that flow in at every open White- Rodgers Attic Ventilator Control auto - window. matically stops the fan for the day. This pro- S '— B • • • • , ,—......... ,.I0,„,,�" ... c- mac; ,- V i a ___., I; ,1 ..,› y . ,-, , _ „• ......., ./.„,„,. ..., . ....„...„ .,,,,,,,,,,,,,,,„,,,,,. ....„,....„,___ . .11 -, J __ Y , � im Illi IS I■ + 1 �� , II 1 1111111.. ir I '" ,, ,P tr , ate— �h I1 S S 0L1111 S� L so - RI w -L 111 � 111 b WHITE - RODGERS THERMOSTAT AUTOMATIC . longs the life of your cooling system and elim- Just as your automatically controlled heating inates the current consumption of unnecessary plant promotes better health, greater economy, daytime operation. convenience and home comfort during the win - As an added convenience, quick removal of ter — White- Rodgers Automatic Attic Ventila- cleaning odors, tobacco smoke, or Fumes of tor Controls provide the same advantages in the any sort is made possible at any hour of the summertime. Equip your Attic Fan with White - day by a manual switch built into the White- Rodgers Controls today and enjoy the added Rodgers Thermostat. This switch operates your Attic Fan directly to provide a complete change comfort, convenience, and economy they offer! of air in just a few minutes time. �4 h, f gym THERMOSTAT The Type 139 White- Rodgers Room Thermostat is an attractive .771 and extremely sensitive bimetallic control designed to turn off the 15 j41u `„ Attic Fan when the air in the house has dropped to the desired temperature —and to turn it on again if the temperature rises. Equipped with recessed thermometer and Touch Temperature Adjustor, accurately calibrated in degrees Fahrenheit. Built -in switch permits manual operation of your Attic an at any time of day. TYPE 2401 ATTIC VENTILATOR CONTROL The White- Rodgers 2401 Attic Ventilator Control contains a dependable clock motor with sealed -in lifetime lubrication. It automatically connects the fan to thermostatic control at a se- $ lected evening time and turns it off at a predetermined morning time. Quickly mounted on or near the fan housing and plugged k r winr into any 110 volt outlet. Contains an extra outlet for connecting I the fan. These controls are of the same high quality and design characteristic of all White - Rodgers Heating Controls MANUFACTURED BY 1209 CASS AVE. SAINT LOUIS, MO. INDEX: 000 -50 UNIT No. R -388 • 4: June 24, 1941 White-Rodgers Electric Company 1209 Cass Avenue St. Louie, Missouri Attention: Mr. G. R. Gibson Gentlemen: We have your letter of June 20th expressing your interest in Ur. Badgett's bulletin on "The Installation and Use of Attic Fans," extracts of whioh you have noticed in the American Artisan. Under separate cover it is our pleasure to send you a copy of the bulletin. You are very generous in offering to furnish us a set of your controls, and, while we feel that it is somewhat cf an imposition, since you have made the offer, may we assure you that we will be more than pleased to accept a set of these controls. If you care to send them to us we will install them in our Fan Testing Laboratory where they will be available for inspection by the many visitors that we have in this laboratory. Very truly, GIBB _ LCHRIST, DIRECTOR By T. R. Spence TRS:pc Vice-Director . 1 , • 1 1 , t,/ 11 AM RICA\ SOCIETY OF HEATING AND VENTILATING ENGINEERS NEW YORK , N.Y. 51 q a on elve-kute /e4e�kiane, AS4 4 -0291 January 19, 1942 Mr. W. H. Badgett Texas A. and ". College College Station, Tex. My dear `%r. Bad ;ett : We are sending you an advance copy of paper to be presented at the 48th Annual Meeting of the Society in Philadelphia, Pa., January 26- 29, 1942, and it is hoped that you will prepare and send in a written discussion (in duplicate) for presentation at the Meeting. Very truly yours, �G SECRETARY AVH : ACS' N enclosure AVAA OFFICERS COUNCIL W. L. FLEISHER, PRESIDENT, New York, N. Y. FOR THREE YEARS FOR TWO YEARS FOR ONE YEAR E. K. CAMPBELL, Kansas City, Mo. E. O. EASTWOOD, IST VICE PRES., Seattle, Wash. A. P. KRATZ, Urbana, III. J. F. COLLINS, JR., Pittsburgh, Pa. S. H. DOWNS, Kalamazoo, Mich. J. H. WALKER, 2ND VICE PRES., Detroit, Mich. W. A. RUSSELL, Kansas City, Mo. E. N. MCDONNELL, Chicago, III. F. E- GIESEKE, College Statlon, Tez. A. J. OFFN ER, New Yark, N. Y. M. F. BLANKIN, TREASURER, Philadelphia, Pa. L. P. SAUNDERS, Lockport, N. Y. T. H. URDAHL, Washington, D. C. G. L. TUVE, Clevel A, E. STACEY, JR., New York, and, N. Ohio Y. A. V. HUTCHINSON. SECRETARY, New York, N. Y. C. TASKER, Toronto. Ont.. Can. C. -E. A. WINSLOW, New Haven. Cann. EX OFFICIO January 29, 1942 Mr. A. V. Hutchinson Secretary,ASH&VE 51 Madison Avenue New York, New York Dear Mr. Hutchinson: My absence from College Station prevented my receipt of your request ror a discussion of Mr. Hinton and 1r. Poor's paper until it was too late for it to reach the convention for the paper's presentation. However, I have prepared the attached discussion which you may include in the transactions of the meeting if you so desire. Until I received orders directing my return to active duty with the Army--this time to the Infantry School at Fort Henning, Qeorgia, I had expected to attend the Philadelphia meeting. I will maintain my College Station address for the present, and possibly for the duration. Sincerely yours, W. H. Badgett WBB:da Attel'I: 1 10) DISCUSSION OF A PAPER PRESENTED BY MR. W. A. HINTON AND MR. A. F. POOR, ENTITLED "THE EFFECT OF ATTIC FAN OPERATION ON THE COOLING OF A STRUCTURE" By: 7ie H. Badgett College Station, Tex. 1. The author a have, I believe, overlooked one of the most important effects secured from the operation of an attic fan, and seemingly have thought of it largely only as a means of reducing the indoor air temperature, and that of the mass of the building. One of the greatest benefits resulting from the use of attic fans is in the early evening hours through introduction into the house of large volumes of cooler outdoor air in which the occupants may place themselves, thus enjoying the combines effects of lowered air temperature and increased evaporation of body moisture with a resulting lower effective body temperature. I believe that it is important to have a larger number of air changes in the early part of the night with possible reduced air movement for sometime after the occupants have retired in order to secure continued pre-cooling of the house for the following day. 2. In conclusion No. 7, the authors state that the gross area of the discharge openings should not be smaller than the intake grille. What they should have re- ferred to is the .effective areas of these openings, for gross .areas can be almost anytAng, whereas the effective area is the controlling factor. Tests at College Station have indicated that more unee3tisfactory operation will result from under- sized discharge openings then from undersized intake grilles. These testa indicate, too, that where possible it is desirable that t? net free area or effective area of the discharge opening be somewhat lerger than the inlet. This avoids the possi- bility of building up a back-pressure with the resulting decrease in operating efficiency and increased noise level. 3. In the 24 -hour test run to compare the two houses without the far: in opera- tion, it is not indicated whether the intake grille of the fan was closed during this test. If the grille remained open, there was in all probability a natural air move- ment fro::, the rooms or the test house out through the attic which would possibly account for the 91i ; htly lower temperature in the test house. 4. It is possible that both the intake and discharge openings in this installa- tion are small for optimum results. Iowever, sines the authors have measured the air movement and converted it to air changes, this will not affect the findings in this paper. 5. Although there is little that is new presented in this paper, it is a valuable addition to knowledge in the field of attic fan operation because it verifies opinions and facts long held by those who have orked r ;ith attic fans. As 1 understand it, this is the foundation for extensive research in the operation of attic fans, and I believe the authors have made a splendid beginning. 6. In their outline of future work, I suggest that the following be included in their studies: (a) Resistance to Sir flow of various types of grilles, particularly ex- panded metal, wooden egg- crote, automatic intake louvers, automatic exhaust swinging doors, and screen wire when used to cover exhaust openings. (b) Determine if possible the -all resistance of average attic fan installation under normal over =:tins conditions. uiiiuips. (b) DetereCne il' possible the . over—all reeletsince o installation under normal operating conditions. (c) Determine the optimum grille velocity from the ;standpoint of efficient operation and satisfactory noise level. The Effect of Attic Fan Operation on the Coolin g of a Structure By W. A. Hinton* and A. F. Poor * *, Atlanta, Ga. This paper is the result of research sponsored jointly by the Atlanta Chapter and the Com- mittee on Research of the AMERICAN SOCIETY OF HEATING AND VENTILATING ENGINEERS in coop - eration with the State Engineering Experiment Station at the Georgia School of Technology. Introduction SUMMARY —The cooling effects of an Further information on summer attic fan were observed under actual use cooling studies carried on at the Re D URING the summer months conditions. A differential of 2 F be- tween inside and outside temperature was search Residence has been reported the minimum outside air obtained with 45 air changes per hour. also by Kratz and his co workers. temperature at night is con An, identical house without an attic fan siderably lower than the maximum was found to be as much as 8 F warmer. Test Equipment and Its temperature of the preceding day. Air changes exceeding 45 per hour were g y found to be uneconomical Arrangement Data from the U. S. Weather Bu- • reau indicate that in Atlanta, Ga., In order to determine more accu- this temperature difference averages rately the cooling effect of an attic - approximately 18 F. The outside of the ASHVE, this investigation fan it was decided that temperature temperature usually starts to drop was undertaken to determine meth- tem p y p measurements should be made in in the afternoon and the decrease is ods of fan selection, operation and in two identical houses located next uite rapid during the early evening stallation which would bring about a q p g y g maximum cooling of the structure door to each other. Two such houses hours. By 10 p.m. approximately were found and a fan was installed two-thirds of the temperature drop and thereby afford the greatest com- P P in one of them. Thermocouples .has occurred. fort to the occupants consistent with were installed in each of the rooms A house and its contents can be economy of installation and opera of both houses. The house without cooled during the late afternoon and tion. It was also desired to obtain a .fan, which will be referred to as early evening by drawing through it data by which cooling effects of the the control house, was used to deter - the cooler outside air. This permits fan could be compared with the nat- p ural cooling of a house. This paper mine the cooling effects caused by the walls, ceilings and floors to natural circulation. The added cool - transfer heat from both inside and describes the method used to obtain ing effects of the fan in the test o u t s i d e surfaces, reducing the this information and contains p re- house could, therefore, be calculated.. amount of heat that must be con liminary' data obtained from test ducted through the building mate- runs made during the summer of The Houses rials to the outside surface. The 1941. A considerable amount of infor The two houses selected are single flow of the cool air increases com- story frame structures possessing ett on the installation and use of identical floor plans. They are the the cooling period. 1 same size and are constructed of the In recent years attic fans have attic fans. Much of this informa- tion is of a general nature regard been installed in a number of houses same kind of material. The houses ing structural details and methods of in this section of the country. These rest on piers and the floors are ap operation. Some cost data were proximately 18 in. above the ground. fans are mostly of the axial or pro- p The distance between houses is a peller type and they are usually hi- also included. proximately 12 ft. Neither house stalled so that outside air is drawn The use of night air for cooling in through the house and discharged was investigated by Kratz, and has a basement. Details of construe from the attic. Various arrange- Konzo. The night air was used to tion are tabulated in Table 1. reduce the daytime cooling load on Each house has a volume of 8,900 ments have been used in making the Y g cu ft. Volumes of individual rooms installations. a cooling system in the Research With the increasing use of these Residence at the University of Illi and the areas of floors, windows nois. Outside air was drawn and door openings are tabulated in fans a need was felt for further Table 2. The windows and doors study of their performance. Through through the house at night while during the daytime the house 'was are not weather stripped and neither the cooperation of the Atlanta Chap- g y has awn house hin s over the win- ter and the Committee on Research kept closed. With this arrange- g ment requirements for artificial down. _ •Assistant Professor, Department of Mechan -• The floor plans of the two houses ical Engineering, Georgia School of Technology. cooling were decreased. *"Graduate Assistant, Department of Meehan- are shown in Fig. 1. Rooms in cor- ical Engineering, Georgia School of Technology. 1 The Installation and Use of Attic Fans, by responding positions in the two Note: Published by permission of the Di- W. H. Badgett. (Bulletin, Agricultural and h g h rector, State Engineering Experiment Station. Mechanical College of Texas.) For presentation at the 48th Annual Meeting 2 Study of Summer Cooling in the Research 3 Study of Summer Cooling in the Research of the AMERICAN SOCIETY OF HEATING AND Residence for the Summer of 1933, by A. P. Residence for the Summer of 1934, by A. P. VENTILATING ENGINEERS, Philadelphia, Pa., Kratz and S. Konzo. (ASHVE TRANSACTIONS, Kratz, S. Konzo and M. K. Fahnestock. ' . January, 1942. Vol. 40, 1934.) (ASHVE TRANSACTIONS, Vol. 41, 1933.) -4. • Reprinted from ASHVE JOURNAL SECTION, Heating, Piping and Air Conditioning I . Printed in U. S. A. NOT TO BE REPRINTED WITHOUT PERMISSION Heating •Pipingod © AirConditioning © o Journal Section Table 1— Structural and Thermal Properties of the Houses Table 2- Dimensions of Rooms and Openings in the Houses COEFFICIENT OF ROOM Room No. VOLUME FLOOR AREA WINDOWS. DOORSb HEAT TRANS- Cu FT SQ FT I _ TYPE OF CONSTRUCTION MISSION U 2 Living room I 1935 193.5 2 2 2 Floor Pine on pine with building paper between 0.34 Front bed room IV 1950 195.0 2 Rear bed room. V 1420 142.0 2 2 Kitchen II 2200 220.0 2 2 Outside Wall 2 is sheet x 4 in. o ck outside de 16 in n . lap inside V2 in. 0.25 Hall III 1390 139.0 0 s ro, ousi i. lap siding on % 10 in. pine sheathing Total I 8895 889.5 8 Roof Composition shingles on % in. pine a Wood sash double hung 33x72 in. Ceiling 1 /2 in. sheet rock. 2 in. x 6 in. joists on 16 in. 0.437a b Wood panel 3 x 7 ft. centers a Combined roof and ceiling coefficient. ner the outside lional Association of Fan Manu f ac- air could be drawn in through the Hirers. At the same time anemom- houses were used for similar pur- windows and then through the eter readings were taken under the poses. Fig. 1 also shows the loco- rooms and the hall and finally grille at 15 stations. The average through the grille opening. The fan values of the air velocities at the tion of the thermocouples and the location of the intake grille of the discharged the air into the open grille were plotted against corre- di • attic space. A louvred opening in sponng volumes in cubic feet per fan in the test house. Both houses were occupied dur the gable supplemented by openings minute computed from the pitot tube ing the tests. The test house was placed in the eaves enabled the air readings. The curve obtained (Fig. occupied by two adults. The control to escape from the attic to the out- 4) was used in computing the rates house was occupied by three adults. side. of air flow from anemometer read- An anemometer, range 200 to ings taken during the test runs. The Fan 2000 fpm, was used to measure the rate of air flow. This instrument The fan installed in the test house was calibrated prior to its use in the FAN is an axial type, 36 in. in diameter tests. The calibration was made for ®�., '� and fitted with four blades. It is this particular use. The fan was set RILLE CEILING LINE rated to deliver 10,000 cfm at a up in the laboratory and equipped speed of 350 rpm and 0.01 in water with the same intake box and grille LIVING ROOM MALL BED ROOM gage static pressure. The arrange- that was to be used in the test house. Fig. 2 — Fan installation in test house attic • f - ment of the fan installation is shown The fan intake box and duct are in Fig. 2. The opening - in the ceil- shown in Fig. 3. A duct with pitot ing was covered with an expanded tube stations was attached to the The Thermocouples metal grille having 70 per cent free discharge side of the fan. By plac In the two houses 90 thermo area. The grille opening is 5 ft long ing different size orifices on the dis- and 3 ft 10 in. wide. Two ceiling charge end of the duct, varying rates couples (iron constantan) were in- joists run length wise of the open- of air flow were obtained. With the stalled. They were checked for ac- ing, reducing the gross area to 17.5 fan in operation, pitot tube readings curacy by comparison with a mer- sq ft. were taken according to the Stand- cury in glass thermometer which With the fan installed in this man- and Test Code Procedure of the Na - had been calibrated by the U. S. Bureau of Standards. Thermo- , couples were placed in each room +s ' and in the hall of the test house in F y B PORCH + i + + PORCH the following positions : Breathing I ' +� I ' — +5 level ; floor level ; and ceiling. Hori- II -1 +_ + �� +B +5C +B 5+ +_ zontal distribution was used at each ri rQ level. In addition, thermocouples B F +_ +B s + . +B +5= +B I were placed in contact with the walls * E o +5 an sur d f ceace ilintemgs of each roam could = bes o mess - that +C +B + +C +5 II + F +F +_ + B +5 temperatures II II la � + F 5 = ured. In the control house thermo- v +B +B +SC +B =1. 5 Y couples were located at various I +B +5 + C s + levels in all rooms and in the hall. II += F B +8 - A few thermocouples were also voi +C +5 placed in the attic, on the roof and $ PORCH MI . PORCH MIII just outside of both houses. The ® — = thermocouple locations are shown in CONTROL HOUSE TEST HOUSE + Fig. 1. N The leads from all thermocouples Fig. 1 —Floor plans showing location of instruments were run to an instrument booth • Key: I Living Room; 3I Kitchen; .III Hall; IV Front Bed Room; V Rear Bed Room,; VI built between the two houses. They Pantry; VII Bath Room; VIII Instrument Booth; R Location of Temperature Recorder Bulbs. Thermocouple locations are indicated by marks l'bllowed by letters indicating levels of positions, were connected through switches to as follows: F Floor Level; B Breathing CeipLe l ; Surface Ceiling; Floor. Surface Temperature; SC Surface of a potentiometer. Fig. 5 shows the 2 . I - i 1 1 5 '1 : lii;- ' 1 ' . ..'' k l , '' . , 01 , , , ,*,,.‘ ,;:;!::: a ., .. . g '" 1 1 t +tk. Fig. 3 -The fan and duct as set up in the laboratory Fig. 5 - The instrument booth showing switches and 9 the thermocouples was continued the closed rooms can be considered • W and complete sets of observations as negligible compared with the e Fr were made at approximately 30 -min total volume of air handled by the 1 T intervals during the run. The rate fan. 8 III of air circulation for each run was One 24 -hour run was made to 0 5 ■.■ determined by taking 15 anemome- compare the test house and the c on - 5 . ter readings un- 4 der the grille and Table 3- Tabulation of Data Taken on Typical Run u 3 then u s i n g the TEST HOUSE 1111 anemometer Cali- . _ � bratldri curve. TIME OF DAY 3:25 1 4:05 15:00 5:30 6:30 7:30 7:55 8:20 8:55 9:25 9:55 X A® A number of Living Floor 86.5 85.9'86.8 88.987.5 85.5 85.7 85.5 84.5 84.5 84.0 ti 1 Room B. L. 89 .3 90.2 91.0 88.9 87.5 85.5 85.7 85.5 84.584.5 84.0 variations were Temp. Ceil. 92.0 91.3 93.0 87.0 90.0 87.5 86.5 86.5 85.0 85.0 84.0 0 1 2 3 4 5 6 made on the above Front Floor 87.5 91.2 89 .51 .0 87.8 85.5 82.8 82.5 81.8 81.2 80.0 79.0 AVERAGE ANEMOMETER VELOCITY - po FT./ MIN Bed B. L. 89.0 91 .8 90 .5 89 85.5 83 .5 82.5 81 .2 81.0 79.5 78.5 Fig. 4- Calibration curve of p rocedure. T h e Room Ceil. 90.0 92.091 .0 .5 86.8 83 82.5 81.8 81.5 80.2 79 .5 anemometer ti of starting Rear Floor 85.8 89.2 88.587.8 85 .5 82.8 82.0 81.8 81.0 80.0 79.2 the fan was varied Bed B. L. 87.0 91.5 89.5 87.8 86.5'84.0 83.2 82.0 51.5 80.5 79.5 Room Ceil. 87.8 92.0 90.5 89.8 87.2183 .2 83.0 82.0 81.2 80.5 79.5 from 12 noon to arrangement of switches and poten- Kitchp. en Floor 86.0 89 .0 89.0 88.0 85.0,84.2 84.584.5 84.583 .5 8 .5 5 p.m. During Tem. 88.5 90.5 90.0 88.2 85.5 85.5 85.5 84.5 84.5 t4.0 82 tiometer in the instrument booth. some runs the fan B de L il . . 9 0.8 91.8 91.5 90.2 87.0 85.2 85.584.5 84.5 83.5 82.5 In order to supplement the ther- was turned off at Hall Floor 85.8 89.0 87.8 87.5 84.7 8 .2 82.2 81.8 81.079.8 mocouple readings, two temperature Temp B.L. 87.3 91.2 89.5 89.0 86.2 84.7 83.0 82.5 81.3 80.7 80.5 approximately 9 recorders were installed. These re- w h i 1 e on Avg Temp corders were kept in adjustment to p.m., Under Floor 83.0 84.5 84.0 84.2 80.8 80.5 80.0 79.8 80.0 78.8178.5 others it was per- Avg. Outside give readings the same as the de mitted to operate Temperature 91.0 91.2 88.0 86.2 82.2 81.2 81.580.2 79.8 78.2,76.0 orated thermometer. One recorder until e a r 1 y the Avg. At tic Temp 106.2 108.5 94.2 92.4 88.3185 84.4183 .5 82.4 81 .3 was set up in the hall of the test house. A record of the average in- next morning. SURFACE TEMPERATURE side air temperature could thereby The front and be obtained. The other temperature , rear e n t r a n c e L Room 89. 90.3 89.7 88.8 87.6 85.8 85. 85.1 2 84 8 3 .4 8.4 82.7 doors were always Front Be Room 90 91 90 89.3 87.3 85.3 84.2 . 82 8 1.1 wa y recorder was installed in the instru- Kitchen e Room 896 90. 89 88.4 86. 85.5 85.2 84 84.0 82.7 82.3 ment booth with the bulb located to , closed during a . 1 give outdoor air temperatures. run. On some of CONTROL HOUSE j the runs one or O eratin Procedure more of the rooms Living B. L. 92.0 89 .2 92.5 93.0 .... 9 89.0 87.2 87.5 86.8 87.5 p g Room Ceil. 95.0 93.5 94.5 94.0.... 92.0 89.5 87.5 82.5 87.0 89.0 W8S Completely Fr. Bed B.L. 91.0 91.8 92.2 93 .0....91.090.288.288.287. Each test run involving the opera c 1 o s e d off. In Room Ceil. 95.0 95.0 96.0 95.0 .... 92.5 92.0 91.0 90.0 89.5 89.0 tion of the attic fan was carried out such cases the Back Bed B. L. 88.5 91.5 91.0 91.8 .... 90.5 89.5 88.5 88.2 87.2 87.5 according to the following general v o 1 u m e of the Room Ceil. 93.5 95. 95.0 95.0 .... 92.5 92.0 91.0 90.0 89.0 89.0 outline. Just before the fan was Kitchen B. L. 93.8 89.2.90.0 92.5 .... 90.5 89.5 88.2 88.8 87.8 87.5 turned on a set of thermocouple open room S Temp. Ceil. 97.0 94.0 94.0 95.0 .... 92.5 91.5 91.5 90.0 89.5 88.5 readings was taken. A set of ' read through which the Hall B. L. 88.5 90.5 88.8 92.8.... 90.8 89.5 86.5 87.8 87.5 87.8 air was circulated Temp. Ceil. 88.0 92.0 92.0 94.0 .... 92.5 92.0 88.0 90.0189.0 89.0 ings consisted of one reading for each of the 90 thermocouples in- Was used to com- Avg. Attic Temp . 108.5 108.7 109 . 01107.2 .... 98 .8 96.8 95.5 stalled in both houses. The temper- pute the number B L. = Breathing Level. of air changes per Fan in operation from 4:50 to end of run. es atures were recorded to the nearest g p Dark at 20. and kitchen in test house closed off. F. The windows and doors were hour. The amount Living ro Air changes per hour, 80. opened or closed as desired and then of infiltration o f All temperatures are averages of several thermocouple readings, degrees Fahrenheit. the fan was turned on. Reading of air drawn through Date of run September 2, 1941. • 3 Heating •Piping an d © Air Conditioning Journal ©0 Section no trol house from the standpoint of . their heat capacity, measured under 100 normal air circulation conditions. In this run the grille opening to the fan =",� and all the openings from the attic a 90 of the test house were closed off. W - INSIDE The fan was not turned off. The e0 OUTSIDE- - s door and window openings were - - 1 1 I FAN ON - -�� identical in both houses. Thermo- . 1 1 I I I couple readings were taken every 70 6 7 8 9 10 II 12 IPM2 3 4 5 6 7 8 9 10 II 12 IAM2 3 4 5 6 7 8 9 hour during the 24 -hour period. TIME OF DAY E.S.T. The personnel available did not Fig. 6— Relation of time and average inside and outside temperatures (55 air changes permit the reading of the thermo- per hour; July 30 -31, 1941; weather, partly cloudy) couples to be continuous over 24- hour periods except during the one 110 run mentioned above. The record- ing thermometers provided 24 -hour records of the test house and out - leo _ I - - door temperatures. Since all the air drawn through the rooms of the a test house entered the hall and was w 90 ; % then drawn up through the fan, the � INSIDE temperature indicated and recorded 80 _ �m�m� '"--- ii� �� by the thermometer placed in the i — OUTSIDE ON - - -- -- -- hall was an average value 'Of the FAN 4 temperatures of the rooms. A com- 70 5 6 7 8 9 10 II 12 IPM2 3 4 5 6 7 8 9 10 11 12 IAM2 3 4 5 6 7 8 9 parison oco of the e readings gs open room TIME OF DAY E.S.T. the Fig. 7-- Relation of time and average inside and outside temperatures (57 air changes readings of the temperature re - • per hour; August 9 -10, 1941; weather, clear) corder in the hall shows that they are in close agreement (Fig. 11) . 110 Weather observations were recorded I qualitatively. 100 Results and Discussion - During July, August and Septem- a 90 ber, 30 test runs were made. The r% results from typical runs are pre - 1- ,1 . ‘---''''-'r - INSIDE sented in the tables and figures. The eo � - OUTSIDE- - - - -_ -- '� period of fan operation ; the number of air changes per hour ; and the 70 1 ' l 1 F N -.N1 1 1 1 1 1 1 temperature data are indicated on s 6 7 8 9 10 II 12 IPM2 3 4 5 6 7 8 9 10 II 12 IAM 3 4 s s 7 a 9 each curve. The temperature indi- TIME OF DAY E.S.T. e p cated for • a particular room is the Fig. 8 - Relation of time and average inside and outside temperatures (80 air changes average of the readings of all breath per hour; September 3 -4, 1941; weather, clear) g g ing level thermocouples in that room. The average inside air tem 106 I , peratures of the test house, which 106 + ATTIC CONTROL HOU 104 �-_ • ATTIC TEST HOUSE 102 1.110M11.11 0 ROOM I 110 _1-_ • ROOM IT t 2 •ROOM 3Y 96 ..,ROOMY 10C S8 FAN ON 94 ■1.■.1 0 0: 92 L. w 90 90 AVE. TEMP. IN CONTROL HOUSE l�� _ CONTROL INSIDE TEST HOUSE 84— INSIDE RECORDER �` �' HOUSE • . - -- \ \� '' illinill 82 MI \" 80 TEST HOUSE -� �. . ■ OUTSIDE - • / - 78 FAN ON ��r___ 70 1 1 I - '/ 78 I t I 12 IPM2 3 4 5 6 7 8 9 10 I I 12 IAM 3 4 5 6 7 8 9 3PM 4 S 6 7 6 9 10 11 12 TIME OF DAY E.S.T. TIME OF DAY E.S.T. Fig. 9— Relation of time and individual room temperatures Fig. 10— Re'ation of time and average inside temperatures of in test and control houses (60 air changes per hour; Sep - test and cz:ntrol houses (60 air changes per hour; September tember 9 -10, 1941; weather, partly cloudy) 9 -10, 1941; weather, partly cloudy) 4 i • Heating .Piping and, ©AirConditioning Journal ©© Section e � y viously make the space below easier the fact that a kerosene stove was 88 - / FRONT BEDROOM - SURFACE TEMP. to cool. used for cooking purposes while an` 67 , - 1 1 HO 1 1 I Fig. 13 shows a comparison of electric stove was used in the test Ca LIVING ROOM -B. LINE 66 hr — TEST HOUSE ME average breathing level and surface house. 46S lin LIVING ROOM-SURFACE TEST HOUSE temperatures for two rooms of the a �_ B4 _ ::iii r ; .kliMM test house maintained under differ- Attic Openings for Egress of Air tatatatataIMIIIIM100 ent conditions. With the fan in op • titav�= . �ata�e�; At the beginning of this investi- BI FRONT BEDROOM- B.LINE� �1[r.,.B..•� era th li room was kept TEST HOUSE tairrl closed while the other rooms were gation, the louvred opening in the 79 FAN 1 1. open. The surface temperatures in gable of the test house provided only 4 PM 5 6 7 6 9 10 11 IE two square feet of flow area for the TIME OF DAY E.S.T. the living room were found to be q Fig. 13— Relation of surface temperatures slightly lower than breathing level exit of air from the attic. The re- to breathing level temperature (60 air temperatures. This indicates that sistance of air to flow through this changes per hour; September 10, 1941; some heat was being transferred small opening reduced the fan de- weather, partly cloudy) livery. Other openings laced from the air to the walls and ceil- y were placed rooms which were open. ing. In the bed room, which was in the eaves of the house to make a In the run shown by Fig. 9, room open and through which air was total of eighteen square feet. This I was closed at 7 :00 p.m. while room drawn, the surface temperatures increase in area of opening resulted II was closed at 8:15 p.m. From were found to be higher than the in in an increase in fan delivery from these curves it is seen that these two side air temperature, indicating that 6000 cfrn to 7000 cfm. rooms do not cool as rapidly as the heat was being transferred from the After this an additional opening ones left open. The closing of rooms surfaces to the air. The rate of de- was placed in the attic and no ap- I and II increased the number of air crease of surface temperatures was preciable increase in fan delivery changes in the rooms left open. Fig. found to be very close to the rate was obtained. Since the gross area 9 shows that the effect of increasing of decrease in breathing level tem- of the inlet grille was 17.5 sq ft, it the rate of air flow did not produce peratures, as can be seen from Fig. can be concluded that the total area any significant change in the rate 13• of the openings from the attic should of cooling of the rooms that were A 24 -hour test run was made to be approximately equal to the gross left operi. compare the temperatures of the test area of the inlet grille. These results indicate that the use house and the control house when • of air changes in excess of 45 per the fan was idle. The results of Summary hour would be of little benefit so far this run are shown in Fig. 14 in An investigation has been made as further cooling of a typical one which the average breathing level on the operation of an attic fan in a story frame structure is concerned temperatures are plotted for each single story frame structure and the and would, therefore, be uneconom- house. These -- temperatures were temperatures produced have been ical. Further investigation may observed h•. y 'y taking thermo- compared with those obtained at the show that even less than 45 air couple re. • ings. same time from an identical struc- changes per hour will be sufficient. From he curves it can be seen ture not equipped with a fan. A comparison of the temperatures that the emperatures in the control The following conclusions can be in corresponding rooms of the test house -ere approximately two de- drawn from the results obtained house and the control house points grees gher than the test house during thirty test runs, conducted out several advantages of the fan temper t, res, except during the during the summer of 1941, in operation. Referring to Figs. 9 and cooking p:. .ids, when the temper- which operating conditions and time 10, it can be seen that, with the fan ature di er - ' ce was greater, and intervals were varied : in operation, the test house temper- during the—period from midnight, 1. When outside air is drawn through atures start decreasing just after the until 5 a.m., when the temperature a typical single story frame structure at outside temperature drops below ex- difference was approximately one a rate of 45 air changes per hour, the in- isting inside air temperatures, while degree. side air temperatures are lowered to there is a lag of one to two hours The higher control house temper- within two degrees of the existing out - before the control house tempera- atures can probably be attributed to side air temperature. tures begin to drop. From Fig. 9 it can be seen that after several a . hours of fan operation, the individ- ual rooms in the test house are kept loo five to eight degrees cooler than . the corresponding rooms in the con- o trol house. It can also be noted a 90 that the temperature in the test W _ 1 BREATH. LINE C.H. house attic drops down very close BO -" - _• .■a =_ ■� 1 to the temperature of the rooms -- • 's'!�m soon after the fan is turned on, BREATH. LINE T. H. I I I I I while the attic of the control house 70 5 6 7 B 9 10 II 12 I4142 3 4 5 6 7 8 9 10 II 12 IPM2 3 4 5 6 7 8 cools over a much longer period of TIME OF DAY E.S.T. time. The removal of this body of Fig. 14— Relation of temperatures in test and control houses with fan idle (September hot air from the attic space will ob- " 24 -25, 1941; weather, cloudy, precipitation 0.36 in.) 6 1 2. With 45 air changes per hour the less than the gross area of the intake Acknowledgments differential between inside and outside grille. temperatures is maintained effectively The authors wish to express their constant. The slopes of the curves for Outline of Future Work appreciation of the cooperation of inside and outside temperatures are prac- J. A. Miller, president and general tically equal. 1. Investigation of effect of lowering manager of the Exposition Cotton 3. An increase in the number of air number of air changes per hour. Mills, Atlanta, Ga., who made pos changes above 45 per hour does not bring 2. A further study to establish effec sible the use of the two houses. The about any appreciable reduction of this tive temperatures in both the test house cooperation of Mr. and Mrs. J. A. temperature differential, nor does it in- and the control house. (Some preliminary Towns and Mr. and Mrs. A. D. crease the slope of the indoor tempera- data, not included in this paper, were ob- tained during the present investigation.) Garner, occupants of the houses, is ture curve. appreciated also. The authors wish 4. The optimum time in Atlanta, Ga., 3. A study of attic fan installations to thank Dr. F. C. H hten ; Prof. for starting the fan was found to range discharging air directly to the outside, ou g from 4 to 5 p.m. with attic as an inlet plenum. R. S. King; Prof. R. E. Lewis; and 4. A study of attic fan installations K. H. Henley, of the Georgia 5. After the fan has bee in opera- School of Technolo for their as - tion for three or four hours in a eve- which will exhaust the house only at gy, s istance rendered during this invest ning it can be turned off provided t e in- night and the attic only during the day. g side temperature has been lowered ufli- 5. A study of the resistance to air flow igation. The authors wish to ex - ciently unless continued operation i de- in typical attic fan installations including press their appreciation of the splen sired by he occupants to prod pre- a comparison of installed delivery with did cooperation of the Committee on cooling forte i clap` free delivery. Research of the Atlanta Chapter of 6. The test house was found to be 6. Investigation of the combined effect ASHVE, H. King McCain, T. T. five to eight degrees cooler than the of insulation and attic fan operation. Tucker, C. Boynton Cole, F. War- control hou - 7. Investigation of attic fan operation ren Clare. The authors also appre- 7. e total area o the openings n in multi -story houses and in residences ciate the help given by other mem the attic for egress of air should not e of different types of construction. bets of the Atlanta Chapter. • 7