AG 31-011 • REFRIGERANT PIPING DESIGN 16 www.DaikinApplied.com
Sizing Refrigerant Lines
Refrigerant Capacity Tables
) and Appendix 3 (
) provide
refrigerant line sizes for commonly used refrigerants. There
is data for suction, discharge, and liquid lines. Suction and
discharge lines have data for 0.5, 1, and 2°F (0.28, 0.56,
and 1.7°C) changes in saturated suction temperature (SST).
Liquid lines are based on 1°F (0.56°C) changes in saturation
temperature.
The data is based on 105°F (40.6°C) condensing temperature
(common for water-cooled equipment) and must be corrected
for other condensing temperatures (air-cooled equipment is
typically 120 to 125°F [48.9 to 51.7°C]). The tables are also
based on 100 feet (30.5 m) of equivalent length. The actual
pressure drop is estimated based on the actual equivalent
length of the application using equations in the footnotes of the
refrigerant capacity tables.
Tip:
Saturated suction temperature is based upon the pressure leaving the evaporator and represents
the refrigerant temperature as a gas without superheat. The actual refrigerant temperature leaving the
evaporator will be higher than this. The difference between the two temperatures is called superheat.