Document MM7GoE2Y1p86NBNjVVQkED6jV

412 Chapter 22 1945 Guide -blowers (filters optional)rand coilsr'-Usually used where'there'is'aii existing radiation or ventilating system. Controls provided with each unit. 3. Non-mechanical type containing coils, using air ejected under pressure from a remote source for inducing circulation over coils (see Chapter 20). Manual or auto matic control of air temperature only is provided. Both summer and winter air con ditioning functions may be performed by the one unit. ~-- One coil for cooling~ahd heating may be provided or a single coil used, through which hot water in winter and cold water in summer is circulated. All three types of systems require remote sources of refrigeration, with the first group obtaining outside air from the window, the second group having no outside air unless used ini connection with a central plant or ventilating system and in the case of the third group, all air delivered under pressure is outside air. - Various combinations or alterations of these room units are available. Different filtering, humidifying and air delivery methods are employed Unit Air Conditioners,' Unit Air Coolers, Attic Fans 413 .without sacrificing quality from an engineering point of view. Furring in of duct work, and building in and refinishing to match existing furniture and fixtures are ways this may be accomplished. Where location of equipment outside of conditioned space is possible, use may be made of storageraqms, halls, basements or any space less valuable than that to be conditioned. Less emphasis need be placed on the appearance of equip ment. However, choices of equipment location are frequently influenced by such economic factors as. long runs of insulated ducts in order to locate ' units near refrigeration sources, versus short duct runs but long extensions -of service facilities. Care must be taken that equipment will not be damaged by climatic conditions. Air distribution from units located .within the conditioned area is by means of grilles,' either fixed or adjustable and mounted in air distribution Fig. 6. Suspended Propeller Fan Type Unit Air Conditioner to achieve the desired conditions. A typical remote floor type room unit air conditioner is shown in Fig. 7. ' Application In the application of unit air conditioners it is important to consider several factors: 1. Location of equipment. 2. Air distribution. 3. Multiple units versus central station system. 4. Multiple remote unit system versus a self-contained unit system. 5. Methods of control. 6. Methods of conserving water. 7. Code limitations. In choosing locations for air conditioning units, consideration must be given to the characteristics and use of the conditioned space; type of system contemplated; duct locations; sources of power, water, refrigera tion, heating and drainage; and accessibility of equipment and system for maintenance. Where units are placed within the conditioned area, particular atten tion must be given to air distribution, sources of outside air and .con venience to service sources and facilities previously .noted. Skill and ingenuity are required to produce a neat appearing, inconspicuous job Fig. 7. Remote Floor Type Room Unit Air Conditioner * headers, either furnished with the unit or constructed at the installation, to meet the needs of the application under consideration. A system of ducts and distribution grilles may also be used, similar to the arrangement used when equipment is outside of the conditioned area. The problem of securing a supply of outside air is often a difficult one. The proper design of ducts is of major importance for good air distribution. Chapters 30 and 31 are devoted to these subjects. In the analysis of any large structure to be air conditioned which is divided into small spaces, such as an office building or hotel, a comparison should be drawn between the use of units and a central plant system. This study is one of economics, and should include such factors as first cost, installation costs, obsolescence, depreciation, maintenance costs, return on investment, flexibility, time of installation and possible loss of useful space during installation. This' same analysis should be extended to include a comparison of remote units with self-contained units. Self-contained units are possible where short term leases are involved, or where wiring can readily be brought to location or where existing water and drain facilities are adequate to handle the increased demand of water-cooled models. On