York YCUL0016, YCUL0130 Selection Data, Selection Rules, Selection Procedure, Sample Selection

Selection Data

FORM 150.63-EG1

The ratings shown on pages 18 through 57 are based on unit operation in a well designed and properly piped system.

SELECTION RULES

1.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 temperatures corresponding to pressures at the compressor. In actual practice, suction line pressure drop has the effect of reducing compressor capacity, forcing the compressor to operate at a lower suction pressure to maintain the desired evaporator temperature.

For normal air conditioning applications, size the suction line for a pressure drop of 3 PSI, corresponding to 2°F, for R-22 refrigerant. Thus, the evaporator temperature will be approximately 2°F higher than the compressor suction temperature. Line loss must be taken into consideration when selecting the evapora- tor.

SELECTION PROCEDURE

The air-cooled condensing unit may be selected from the Ratings on pages 20 through 48, if the ambient air temperature at the condenser and the saturated suction temperature at the compressor are known. The ambi- ent air temperature is a known design parameter, but the suction temperature at the compressor, in many cases, is known only within certain allowable limits. The actual compressor operating suction temperature and the overall performance of the system will depend directly upon the choice of the evaporator. Starting with a preliminary evaporator selection at a nominal evaporator temperature and using data supplied by the evaporator manufacturer, enter the ratings tables and select a unit to meet the required cooling load at a suction temperature at least 2°F below the evaporator temperature. The 2°F

allows for normal suction line loss.

If more accurate selection is required, the evaporator capacity should be plotted against the condensing unit capacity to determine the balanced system performance. Again, it is necessary to factor in the suction line loss.

After the system balance point has been determined, the compressor KW input may be interpolated from the ratings tables.

SAMPLE SELECTION

Select an R-22 Air-Cooled Condensing Unit with a matched central station air handling unit having the following operating conditions:

Design Conditions

1.An air handling unit with four large DX coils (two per 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.

Selection

1.Enter the YCUL 60 HZ Rating Table (page 20).

2.The model YCUL0056EC will provide 51.3 tons with 48.3 compressor KW input at 90°F ambient air and 43°F suction pressure.

3.Calculate the compressor KW input for the specific design conditions of 50 tons and 90°F ambient air.

50tons

KW = 51.3 tons x 48.3 KW = 47.1 KW

The YCUL0056EC is the suitable selection for the design capacity.

YORK INTERNATIONAL 9