Document 2NRzOZ7JK6mDeL3D5g59Rqbza

932 CHAPTER 64 - - '1965 Guide And.Data Book aids Publication No. CN-1-1964 establishes teat procedures and contains minimum standards for room air conditioners which have been adopted by nearly all manufacturers;.The various requirements of these ^standards have already been discussed in the paragraph Performance Data. The. NEMA Standards also give a simplified calculation form for determining the heat gain for a given space so that a room air conditioner with the correct cooling capacity nan be selected to match this beat gain. -:>! INSTALLATION AND. SERVICE . ; : . Installation rprocedures vary widely because units can;be mounted in various ways. Therefore,' it s important to con1 sider the most suitable mounting for the installation and-also that it will satisfy the user and comply with existing building codes. ::r ' / T-" Common mounting methods are: Inside flush mounting: Interior face of conditioner is approxi mately flush'with inside edge of window bUL - .- - Balance mounting: Unit is installed approximately half inside and half outride of window.. Outside flush mounting: Outer face of unit is flush or.slightly beyond outride wafl. All-in-mounting: Unit is completely, inride the room, so that the window can be closed. , ,5 Upper uA mounting: Unit is in the top of the window. 1 Special mounting: For casement windows, for office windows with swinging units, dr swinging - windows; to1 permit' window1 washing, and for transom .windows over doorways. , Built-in mounts or sleeves are used for installing window-type chassis or complete.unito, or consoles in walls of apartment build?, ings, hoteU, nwriris'end rosidences. ,' j . ^ ,`j ` ' Roam air.conditioners,are becoming increasingly compact in physical she because of consumer preference for minimum projection both inside and outside the structure, and.a mini? mum loss of-window light. .This has generally , been acconj?. pUshed in capacity sizes up to 15,000 Btuh, and has permitted tire design of-installation mounts which are. simpler, to apply, and more attractive in appearance. -Several types of.expand able mounts,are now available for quicki&nd dependable in-, stallation into single and double hung windows.- - ,.,. .. An increasing percentage of.unite are being applied throuj^i-.. the-wall and this would indicate an advantage;- in cabinets without,side louvres. Coupled withthis is the fact that sngle- and double-hung,windows.np.longer constitute s majority on< new borne and apartment construction, and improved .designs on-.most awning, slider, and casement window , installation mounts should be forthcoming, . Some mountings depend on the window sash.io take some of; the load. In such cases, the,window must be blocked in place.. Otherwise, the unit might; bill out .if the.windpw is;inad vertently raised.. Installation kits provide all. structural, parts needed,for mounting; also gaskete, panels, and seals,,for. weather-tight assembly..The.instructions must be.carefully, followed. ; .>; - Adequate wiring with proper fuses must be providecbfor, the service outlet. The necessary, information is usually giypn on the instruction sheets or stamped .oh the conditioner near .the. service cord. . -. I(ti All room air conditioners regardless of voltage or amperage, are required to be grounded. All units are equipped,.with grounding type plug, caps from the .manufacturer. .Receptacle with ground conductors -should be uj$d when units, are ingfjdlpH ' . '. I Through-the-wall units with steam or hot water coils mipst be wired in or connected.with armored cable or conduit, When the cooling unit can be removed without. disturbing the hating system, however, it has been..aistomary.-to provide adequate plug-in. wire in order to facilitate installation land servicing of the cooling unit.' ; - : The servicing aspect is related to the type of unitifslide out vs integral chassis) ;and the component which -becomes de fective. The integral chasris designs permit servicing of most electrical components (except' compressor and fan motor) by partially dismantling the front (while the installation remains intact). The slide-out types have the advantage of maintain ing window closure while repairs are made on the chassis ele ment. - ' - >- ! FUTUte:^ The trend toward smaller size is oontixming'because of the space, handling,'and cost advantages to the owner. However, to accomplish this successfully, the performance of the unit (capacity, noise, airflow, condensate disposal,- etc.) cannot:be penalized. This requires more efficient-air system designs and intensive testing ofthe aspeicts which-are less critical on-'the more roomy arrangements. The -advent of cooling capacity certification, with;most-manufacturers participating inithe program, is expected to influence future developments because of the need for tighter control of: those components -which affect performance. > `'-1 - -- i Noise reduction (both inside and-outside): is becoming in- creasihgly importanti-'Wbefe inride noise1can be displeasing to the owner, excessive outride noise (condenser-'fan arid com pressor) can be irritating to his neighbor, and loeal ordinances are:being effected in some areas to establish-a maximum' in tensity.'No universally accepted standard -for noise ratings (either for design or application) has been approved, hut active effort is being exerted to accomplish such a standard. As a first step!towards a standard .for -noise1 ratings; ASHRAE Standard`36A-63, giving a method of determining sound power -levels of1 Room -Air- Conditioners,- has been published. - -- ; ........' * .> > >- ' Room air conditioners (primarily through-the-wall-appli cations) ^ can provide year-round comfort -with steam, hot water, or resistance heat.-A-recent development is a combina tion gas heater and riectric powered air conditioner. -.i Year-round-room air conditioners of a< long-low type-have been developed for- high-rise! apartment .applications - pri marily, iand appear to be fulfilling specialiarchitectural needs relative to ahape, projection,',and'structural variation:'Such equipment-competes with fan-coil'systems, land is. most -ac ceptable with low noise levels and-reliable long life construc- .tion. - Individual; room controls provide) different temperatures in different rooms and permit shutting off rooms as deriredi The heating and cooling thermostats for these units are .usu ally built into the conditioner, but sensitive wall-type thermo stats operating.ori low voltage.circuits igive even better con? trol.' Another new development produces improved tempera ture and humidity .conditions by uring room air.conditioners which-reheat the. air .when the humidity is high and the dry- .bulb temperature is relatively.low. > . .1;.- ; Room air conditioners with cooling capacities up to 32,000 Btuh appear to be gaming a much larger share of the market These units are generally. applied in small business establish ments, 1 halls, and houses with a-minimum of. .partitioning: Reverse; cycle units of this type are being used .successfully for heating and :cooling of moderate size.homes in some areas. ' .Small high-speed compressors-driven by two-pole motors are coming1 into. use. Improvement-in ;noise level is to, be .expected.as a result.of current developments..Furthermore, thermoelectric cooling and heating are now being investigated intensively,. and some, experimental ain-ennHitinning equip ment using thermoelectric. principles has been , built How? Room Air1 Conditioners and Dehumidifiers 933 ever, more"efficient ^d^lower.^t^tiiermoelectric/materials are needed, before practical_and;econqmic&lly feasible equip ment can be produced.., DEHUMIDIFIERS 7'> ' . 1 This ;section refers to domestic-type debumidifier..unite which are self-contained,;-electrically operated;1 and-'me-' chanically-refrigerated:'' 1 ` ji. A dehumicfifier is a device which reduces the relative hii- midty of the-surrounding atmosphere. It.provides comfort by dehumidifying and reducing the relative humidity of .cir culating room air, and prevents nlst, rot;'mold, and inildew in equipment!- A dehumiriifier.cqhsiste.'offa motqr-cpmprKsbr unit, an air-circulating fan, a refrigerated-surface :(evapora? tor), a condenser, and a' cabinet' to -house tiiiese components. fig. 2.shows a typical.electric'.dehumidifief`'refrigeration system. The fan draws the moist1 room air through, the cold coil.-The air.is cooled, below.its dew point,. thus.-.giving up moisture which;'dram's off'into.the condensate receptacle-or into the``sewer. The cooled1air of.decreased moistime' passes through the hot condenser, where it is .reheated. Then, "with the addition of.otherunit radiation heat;:the air is discharged into the room at somewhat higher temperature," but much lower relative humidity.'' .. '7 j Continuous,recirculation of'room'air throiigh'.this system gradually, reduces the relative humidity of the.room.air. The Fig. 2 .... Typical Dehumidifying Refrigeration Umt addition ofhumidity control to cycle the system automatically maintains a preselected relative humidity. Controls are normally supplied in the adjustable range of 20 to 80 percent relative humidity. SIZES Domestic dehumidifiers range from 1 to i hp. Their input varies from 200 to 600 watt at 115 volt, single-phase 60-cycle power, sod they can be plugged into ordinary house outlets. Domestic dehumidifiers remove from 5 to 15 quarts of water from the air in 24 hours, and are tested under standard NEMA conditions by most manufacturers. (National Electrical Manufacturers Association, Publication No. DHl-1963. Dehumidifiers (Self Contained, Electrically Operated, Me chanically Refrigerated). Removable water receptacles used with dehumidifiers hold 8 to 11 quarts, and are usually made of plastic or poroelanized steel to withstand corrosion. Emb of removal and handling without spilling is important. On most units, a flexible hose leads to the unit drain or receptacle for gravity drainage to a sewer outlet. Overall sizes and weights of dehumidifiera vary as follows: Width, inches--12 to 14.5 Depth, inches--10 to 20.5 Height, inches--12 to 23.5 Weight, lbs--45 to 75 'Table.2 Typical Dehumidifier Performance Data.. -; Rom cimhifnf Dry Mb 80 f, Wet Balb 69.5 f, tdotno Hait/;60% Compr*ssorHP* Electrical Input Volte' 1 : Watts Amps Electric enerzv kwhr/24 hr, . Air Circulation tV~ 1 ' 115 320 3.5 14.60.4 i-1 1-i 115 '350 3.7 6.9 170 115 440 5.3 10.5 180, i-j ; 115 550 6.4 13.0 190 * Optional Depending on the cost, dehumidifiers are either plain or more decorative. More expensive' models have higher ca pacity, are better styled, and are equipped with a humidistat. These humidistats control the [relative humidity of the cir culating air within 3 percent. They may include an oftan unit line switch. As an added safety feature for automatic dehumidifiers, accessory kite are available to automatically turn off the dehumidifier when the water-receptacle is full- and' requires emptying. This device may or may not.include an' indicating light. Deluxe dehumidifiers are usually, equipped vrith casters so' that[ they `can easily'be moved from place to place- ' Less expensive.models usually are smaller, have lower ca pacity, and are not as decorative as more expensive types. ' -CAPACITY AND PERFORMANCE RATING . Dehumidifier rated capacity is expressed by the number of pounds of water removed from the atmosphere in a 24hour period at standard NEMA rating conditions. For com parison, performance may be evaluated in terms of pounds of condensate per kilowatt hour. Table 2 lists performance data for typical dehumidifiera. DESIGN FEATURES Evaporator surface may be in the form of bare-tube coils and finned-tube coils in both vertical and horizontal tube arrangements. Vertical tubes collect smaller drops and pro mote quicker run-off than horizontal tubes; the latter tubes, therefore, obtain more re-evaporation. With multiple hori zontal tubes, the drops fall on the tubes below. This causes more re-evaporation which is detrimental to performance. Because of high construction costs involved in header con nections of closely spaced multiple vertical tubes, spiral evaporator tubes appear to be a good current design compro mise. This design has most of the advantages of the verticaltube evaporator. Finned tubing with relatively small fin extension aids per formance if the entire surface remains below the dew-point temperature. Otherwise re-evaporation of the condensate occurs. However, finned coils are difficult to keep clean. Evaporators are protected against corrosion by finishes, such as paint, wax, and anodizing (on aluminum). Waxing reduces the wetting effect needed for condensate formation. However, teste on waxed evaporator surfaces vs non-waxed surfaces indicate a negligible loss in capacity. Thin paint films do not appreciably affect capacity either. The air circulated by dehumidifiera in the J to I hp range varies from 125 cfm to 250 cfm. In general, capacity of a de humidifier increases with increase in air flow. Large air flows, however, may cause objectionable noise. Domestic dehumidifiera handle 0.75 to 1 air change par