Reducing Heat Loss in The Adiabatic Section of a Two-Phase Closed Thermosyphon (TPCT) Using Acrylic Tube

Abstract

This study aims to present a method of reducing heat loss in a two-phase closed thermosyphon (TPCT) by replacing copper tubing with acrylic in the adiabatic section. The designs used included total lengths of (L T ) 150, 300 and 450 mm. The evaporator section (L E ), Adiabatic section (L A ) and Condenser section (L C ) lengths were all alike at 50, 100 and 150 mm. The copper and acrylic tubes were of 15 mm external diameter and 12 mm internally. The temperatures applied at the evaporator section (T E ) were 60oC and 80oC. The angles of inclination were 0o, 20o, 40o, 60o, 80o and 90o, and air velocity at the condenser section was 1 m/s. The working fluid used was plain water with a filling ratio of 50% of the evaporator section volume. The experiment showed that as T E increased so did heat flux, however shorter L Ts resulted in lower heat flux, and the maximum heat flux achieved was 5 kW/m 2 at T E 80oC, L E 150 mm, with an angle of inclination at 80o to 90o using acrylic tube in the adiabatic section. When acrylic tube was installed instead of copper tube at L A the resulting thermal resistance (R tube ) Co/W decreased and heat flux increased. The maximum R tube result was recorded at around 2.78Co/W with the acrylic tube of L E 150 mm. with a T E of 80oC.