Discusses the basis of the refrigerant line sizing charts in ASHRAE (1990) and Wile (1977). Describes an interactive computer program that allows rapid calculation of single-phase pressure drops over a wide range of input conditions. The program solves equations for compressible flow rather than using the incompressible approximation. The ASHRAE (1990) line sizing tables are shown to be accurate. The charts in Wile (1977) are shown to underestimate the pressure drop at high flow rates. Shows that the program yields accurate results under all flow conditions considered. It can easily be modified to allow calculation of pressure drops for alternative refrigerants.

KEYWORDS: Calculating, computer programs, refrigerants, pressure drop