York YCUL0016 User Manual

Contents

York YCUL0016 User Manual Manual pdf 9 page image

YORK INTERNATIONAL 9FORM 150.63-EG1Selection DataThe ratings shown on pages 18 through 57 are basedon unit operation in a well designed and properly pipedsystem.SELECTION RULES1. Capabilities are based on Refrigerant 22 or 407C.2. Ratings may interpolated, but must not be extrapo-lated.3. Ratings shown are at saturated suction temperaturescorresponding to pressures at the compressor. Inactual practice, suction line pressure drop has theeffect of reducing compressor capacity, forcing thecompressor to operate at a lower suction pressure tomaintain the desired evaporator temperature.For normal air conditioning applications, size thesuction line for a pressure drop of 3 PSI, correspondingto 2°F, for R-22 refrigerant. Thus, the evaporatortemperature will be approximately 2°F higher than thecompressor suction temperature. Line loss must betaken into consideration when selecting the evapora-tor.SELECTION PROCEDUREThe air-cooled condensing unit may be selected fromthe Ratings on pages 20 through 48, if the ambient airtemperature at the condenser and the saturated suctiontemperature at the compressor are known. The ambi-ent air temperature is a known design parameter, butthe suction temperature at the compressor, in manycases, is known only within certain allowable limits.The actual compressor operating suction temperatureand the overall performance of the system will dependdirectly upon the choice of the evaporator. Starting with apreliminary evaporator selection at a nominal evaporatortemperature and using data supplied by the evaporatormanufacturer, enter the ratings tables and select a unit tomeet the required cooling load at a suction temperatureat least 2°F below the evaporator temperature. The 2°Fallows for normal suction line loss.If more accurate selection is required, the evaporatorcapacity should be plotted against the condensingunit capacity to determine the balanced systemperformance. Again, it is necessary to factor in thesuction line loss.After the system balance point has been determined,the compressor KW input may be interpolated fromthe ratings tables.SAMPLE SELECTIONSelect an R-22 Air-Cooled Condensing Unit with amatched central station air handling unit having thefollowing operating conditions:Design Conditions1. An air handling unit with four large DX coils (twoper circuit) having a total cooling load of 600 MBH(50 tons).2. The coil suction temperature required 45°F.3. The design outdoor ambient temperature is 90°F.4. The power supply is 460V/3 phase/60 HZ.Selection1. Enter the YCUL 60 HZ Rating Table (page 20).2. The model YCUL0056EC will provide 51.3 tons with48.3 compressor KW input at 90°F ambient air and43°F suction pressure.3. Calculate the compressor KW input for the specificdesign conditions of 50 tons and 90°F ambient air.KW = 50tons x 48.3 KW = 47.1 KW51.3 tonsThe YCUL0056EC is the suitable selection for the designcapacity.