Document 0qnpBDLdoRx6Dq8rnDwZE3Rrk

HEATING VENTILATING AIR CONDITIONING GUIDE 1940 1. Central system with heating and cooling coils and humidifying sprays (Fig. i) This system is very common and used extensively for summer and winter conditioning! 2. Central system with preheating coil, washer and reheating coil (Fig. 2). This is widely used for winter conditioning on larger installations. Summer conditioning is accomplished by using cold water in the washer. 3. Blow through system with heating and cooling coils and mixing dampers (Fig. 3). This is used where several different zones are served from one central system and the conditioning of the entering air for each zone is obtained by mixing varying quantities of air after passing through the heating and cooling coils. Fig. 1. Central System with Coils and Sprays CHAPTER 21- CENTRAL SYSTEMS FOR COMFORT AIR CONDITIONING Fig. 3. Blow through Systems with Coils and Mixing Dampers i s 1f 5 tet fi /!* a. Humidifying sprays moor P s 1Motor IFen X 8 c < 'o y. Op 21 cc = oo s & 4-J LjJ Supply duct zone-2 Fig. 4. Central System with Recirculating Conditioners 4. Central outside air conditioning system with zone recirculating conditioners (Fig. 4). This is used on installations having large zones requiring independent control to meet local requirements for office and apartment buildings, hotels, etc. 5. Central conditioning system using either washer or coils with booster reheating coils (Fig. 5). This is used for special zone control where there is great variation in heating requirements of different spaces, as may be caused by different exposures to wind and sun. 6. Residential system. In Fig. 6 is shown a combination of unit equipment used for residential air conditioning. The arrangement is similar to Fig. 1, but the coil, humidi fier, and.fan section may be purchased as a unit. The sketch shows a system.which permits the use of radiators or convectors in kitchens, baths, garages, and similar rooms. 378 Fig. 5. Central System with Booster Coils 379