3443 (RP-392) -- Pool Boiling Data for Five Refrigerants on Three Tube Geometries ✓ Most Recent

Work has been performed to provide basic nucleate boiling data on a 26-fpi integral finned tube and two enhanced tube geometries. Data were taken with refrigerants 11, 12, 22, 113, 123, and 134a at 80 deg F (27 deg C). Presents the data and shows comparative pool boiling performance of the various refrigerants and tube geometries. The data were taken on 6.5in. (165mm) long tubes having an outside diameter of 0.75in. (19.05mm). Each tube has two internal axial grooves machined diametrically opposite for thermocouple installation. The grooves are along the total tube length and were machined by electrostatic discharge machining. The tubes are soldered to a brass flange that can rotate inside an annular brass flange. This allows for checking the consistency of the temperatures indicated by the two wall thermocouples. Heat is supplied to the tube by a cylindrical electrical cartridge heater 6in. (152.4mm) long and 0.375in. (9.53mm) in diameter with a maximum power output of 1,700 Btu/h (500 W). The 26-fpi tube pool boiling coefficients for R123 and R134a are approximately equal to the values measured for R11 and R12, respectively. For one of the enhanced tubes, the boiling coefficients of R123 and R134a are approximately 40% and 10% below those of R11 and R12, respectively. However, the other enhanced tube shows a different performance. Its performance for R123 and R134a is approximately 20% and 10% below the corresponding boiling coefficients of R11 and R12, respectively. Work is currently in progress to repeat the same data at 40 deg F (4 deg C).

KEYWORDS: refrigerants, tubes, boiling, finned tubes, R11, R12, R22, R113, R123, R134a, temperature, length, diameter, measuring, performance, comparing