Document BR99YVbNDDeRELznOVe314OBk

602 CHAPTER 25 1955 Guide REFERENCES 1 See National Association of Fan Manufacturers standard definitions in Chapter 33. * Standard Code for Testing and Rating Steam Unit Heaters--Adopted jointly by The American Society of Heating and Ventilating Engineers and the Industrial Unit Heater Association, Second Edition January 1950 (IUHA Bulletin No. 10). * Standard Code for Testing and Rating Hot Water Unit Heaters--Adopted jointly by The American Society op Heating and Ventilating Engineers and the Jnduslrial Unit Heater Association, Second Edition April 1953 (IUHA Bulletin No. 11). * A.S.H.V.E. Research Report No. 958--Temperature Gradient Observations in a Large Heated Space, by G. L. Larson, D. W. Nelson and O. C. Cromer (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 243). A.S.H.V.E. Research Report No 1011Tests of Three Heating Systems in an Industrial Type of Building, by G. L. Larson, D. W. Nelson and John James (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 185). `ASH V.E Standard Code for Testing and Rating Steam Unit Ventilators (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 25) (Effective Jan. 1, 1934). * A.S.H.V.E. Research Report No. 936--Investigation of Air Outlets in Class Room Ventilation, by G. L. Larson, D. W. Nelson and R. W. Kubasta (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 463): A.S.H.V.E. Research Report No. 1017--Air Supply to Classrooms in Relation to Vent Flue Openings, by F-. C. Houghten, Carl Gutberlet and M. F. Lichtenfels (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 279). CHAPTER 26 UNIT AIR CONDITIONERS AND UNIT AIR COOLERS Definitions, Classification of Unit Type Equipment, Component Parts of Unit Type Equipment, Sound Isolation, Modifications of Remote Units, Ratings of Unit Air Conditioners, Application of Unitary Equipment, Unit Air Coolers THIS chapter presents the physical characteristics of air cooling units and air conditioning units; a suggested procedure for selection of units; and some of the factors involved in the application of unitary equipment. In general, factory produced unit equipment can be obtained to accomplish all of the functions possible from field assemblies, but the advantages of unit, equipment are most apparent in small and moderate capacities. Above 12,000 cfm capacity, or approximately 40 tons of refrigeration capacity, handling and assembly costs generally favor the use of field assembled units. Multiple application of unitary equipment is frequently justified for large gross tonnage installations where zoning or a minimum amount of air distributing ducts is desirable. DEFINITIONS The term air conditioning unit has been loosely used as a name for all types of factory produced air handling, cooling, or heating units. A joint committee1'2'3 on Rating Refrigerating Equipment has defined the various types of unitary equipment: 1. A Cooling Unit is a specific air treating combination consisting of means for air circulation and cooling within prescribed temperature limits.1 2. An Air Conditioning Unit is a specific air treating combination consisting of means for ventilation, air circulation, air cleaning, and heat transfer, with control means for maintaining temperature and humidity within prescribed limits.1 . 3. A Cooling Air Conditioning Unit is a specific air treating combination consistmg of means for ventilation, air circulation, air cleaning, and heat transfer, with control means for cooling and maintaining temperature and humidity within pre scribed limits.1 4. A Self-Contained Air Conditioning or Cooling Unit is one in which a condensing unit is combined in the same cabinet with the other functional elements. Selfcontained air conditioning units are classified1 according to the method of rejecting condenser heat (water cooled, air cooled, and evaporatively cooled), method of introducing ventilation air (no ventilation, ventilation by drawing air from outside, vumatin by exhausting room air to the outside, or ventilation by a combination the last two methods), and method of discharging air to the room (free delivery or pressure type). 5. A Free Delivery Type Unit takes in air and discharges it directly to the space to oe treated without external elements which impose air resistance.1 6. A Pressure Type Unit is lor use with one or more external elements which im pose air resistance.1 ,? A Forced-Circulation Air Cooler is a factory encased assembly of elements by which heat is transferred from air to refrigerants.* CLASSIFICATION OF UNIT TYPE EQUIPMENT . Field assembled apparatus as described in Chapter 30 can be designed 111 shape, size, and capacity for any application, with the refrigeration and 603