Document M4mz7yd5G9Z5moGMVkm385LQL

448 CHAPTER 18 1952 Guide i' REFERENCES The engineering data were obtained from University of Illinois, Engineering Experiment EtationBulletins Nos.'141,188,189 and 246; Warm Air Furnaces and Heat ing,Systems; by A:: C.1 Willard, A. P. Kratz, V.S. Day',"and S: Konzo. See also Manual: 5: .Gravity Code, and Manual for the Design and Installation' of Gravity Warm Air Heating Systems' Third Edition, 1947, published by. the National Warm AirHeating dhdAir Conditioning Association. `.Simplified Procedure for Selecting Capacities of Duct Systems for Gravity Warm Air Heating Plants,;by A.-P: Kratz and S. Konzo {University of Illinois','Engineering Experiment Station CircularA5, Dec.,,1942). . . .. ; . , `gravity,.Code and Manual for the Design and Installation of.Gravity Warm Air Heating Systems, Manual 5, Third Edition, 1947, National Warm Air Heating and Air Conditioning Association. ; ,i' iL CHAPTER 19 FORGED WARM AIR SYSTEMS Air Distribution, Standard Combinations of Parts, Simplified Method of Design; Design Procedure for Large Systems, Automatic Controls,-Adjustment-of System' for Continuous Air Circulation, Ceiling Panel Systems, Perimeter Systems, Cooling Methods, Design of Cooling System IN forced warm air or fan furnace heating systems, the air circulations is effected by motor-driven centrifugal fans, commonly referred to as blowers. The advantages of forced air systems, as compared with gravity systems, are: 1. The furnace need not be centrally located but may be placed in any part of the V basement. 2. Basement distribution ducts can be made smaller and can be so installed as to give full head room in all parts of the average basement, or-be completely concealed;: from view where desired. 3. Circulation of air is positive, and in a properly designed system, can be balanced S in such a way as to give a greater uniformity of temperature distribution. ' 4. Humidity control is more readily attained. - ; t' 5. The air may be cleaned by sprays or filters, or both. 6. The fan and duct equipment may be utilized for a complete-cooling and de- humidifying system for summer, using either ice, mechanical refrigeration, dr low ! temperature water for cooling and dehumidifying, or adsorbers for dehumidifying. 7. The use of the fan increases the volume of air. which can be handled, thereby* increasing the rate of heat extraction from a given amount of heating surface and insuring sufficient air volume to obtain proper distribution in a large room. 8. Ventilation air may be positively introduced and heated. The construction features of forced warm air furnace units and the function and selection of the various parts of a system are discussed in Chapter 15 and other publications.1 AIR DISTRIBUTION The. conditions of comfort obtained in a room are influenced greatly by the type of register used, and the locations of the supply registers and return grilles. In general it has been found that changes in the type, air velocity, and location of the supply register affect the room conditions much more than the changes in the location of the return grilles.. One method is to locate the supply register near the floor,, or high in the side wall, so that the warm air from the register blankets a cold waD, and mixes with the cold Air descending from the exposed walls and glass.' Another method is to locate the supply openings near the floor, or high in the side wall, on the inside wall, and the return openings near the greatest outside exposure. In any case, the warm air registers should be located so that the air stream never discharges directly against people at rest. Tests' in Warm Air Research Residence No. 1 at the University of Illinois, have indicated that continu ous blower operation gave better results than intermittent operation. 449