Document wD8DmJK4wDjB7D1QadkzbL8q3

576 CHAPTER 25 1952 Guide / /- . MODIFICATIONS OF REMOTE UNITS Features of various modifications of remote air conditioners are given in'the following paragraphs. Spray Type'Unit tFig.,4 shows a spray type unit used by designers who prefer air washing 'and, coil wetting features. These units are equipped with a pump that sprays water or brine over the coils. Due to the direct mixing of .the condensate and the spray, provision must be made for overflow in summer and replacement of water evaporated in winter. - Dehumidifying Units ! In a further.modification of spray type units, absorbent brine solutions suehas lithium chloride are used to remove,moisture.from the air. As explained in; Chapter .37, the. latent heat of the moisture, removed is ..changed to sensible heat, so that coils must, be used as after-coolers to obtain the right dry-bulb temperatures. Factory produced quits are also available.for use with solid adsorbents such as silica gel. Remote Room Units For individual rooms, with coolingdoad requirements of to 1 tons, remote units are available in attractive; casings for installation within the room. A suspended; type is: shown in Fig. 3 and a floor .type, such|;as,rs usually installed in. place : of an existing; radiator, is . shown in . Fig;.f5. Furnished jvith chilled water from a icentral plant,, these units; ofierfja satisfactory method1 of conditioning- existing, offices, flotel, and apartment rooms. These units may be obtained with<ffite$;nd outside; air;.con nections, bui'for: most'satisfactory application are ugqd as supplements to central systems that supply propeHy, conditioned andr filtered.,, air to the areas served... ;0 .-. Induction type units, using primary conditioned air under pressure to induce local circulation, are described in Chapter 29. .. ni Self-Contained Units f ; 't A-typical.large selfrcontained tthit is'shown-in Fig. 6;:-;;It is essentially -a remote-vertical type conditioner mounted on tbp qf 'a sound -insulated enclosure containing the cbndensing:iihit. /` 'Air'distrifediibn de obtained by means of grilles mounted' in the discharge plehum- wheii'the unit is located in the conditioned area. 'Duct 'distribution of cbhditibhed airman be obtained. by removing.tlie plenum, connecting directly .to. the blower dis charge, and safing the top of the uhit.a-.Pif.;'/ - The beat generated hy-the compression7bf refrigerant-gases and that given off byrthe' electric motor'are removed from the compressor cbiiapartment in four ways: by the use of a water coil in the compressor compart ment ; by utilizing the cold suction gases; by drawing part of the return air through the compressor compartment, and finally by circulating room air through the compressor compartment by means of a fan attached to the motor shaft. - The 7J, 10, and 15 ton self-contained units usually have horizontal type conditioners. ..The condensing unit enclosures are not completely sound insulated, since they are. not- usually, installed in. the conditioned area. Most units can be divided into two or three sections for ease of Unit Air Conditioners and Unit Air Coolers 577 handling and installation. Although most large self-contained units have water-cooled condensers, the 7J, 10, and 15 ton units can be obtained for operation with evaporative condensers. ; Self-Contained Room Cooling Units Small self-contained units can be obtained with water-cooled conden sers, but they are generally air cooled. .... .... The air-cooled types are small in capacity, ranging from | to 1-j hp. Their principal application is for conditioning such spaces as hotel rooms, offices and, residential .living1 quarters..-A duct connection; between? the unit and an .outside window, or ventilated air .'shaft is required to permit Fig. 6.'Self-Contained . Wateb-Cooled Aib CONDITIONEB , :. .. Fig. 7. Self-Contained Aib-Cooled. Unit ", AlB, CoNDITIONEB . disposal of the heat extracted from the conditioned- area. The unit may stand in front of the window or be mounted oh the window sill! Various styles and types of windows encountered tend to increase the difficulty of making the window connection's. The evaporation of condensate on the condenser coils, as a means of. disposing of moisture, will tend to increase the condensing capacity, and reduce the operating head, pressure. Some units add supplementary water so that increased capacity may be obtained from constantly wetted condenser coil surface. Connections to an electrical outlet may be made through a conventional cord and plug or a permanent electrical connection, depending on local code rulings per taining to the installation, of small motors. The exterior finish of the unit in metal, wood or fabric, is decorated to. harmonize with office or bedroom furnishings. ... ,. ; A unit of the air-cooled condenser type for floor mounting is shown in Fig. 7. Of the two fans shown, the lower one acts as- condenser air fan, and-in some units this fan is. arranged with slingers for discharging con densate on the condenser coil, while the upper fan discharges airuntothe conditioned area. A feature of the design shown in Figi 7 is that the