Experimental Investigation of an Air-to-Air Thermosyphon Heat Exchanger Using ε -NTU Method

摘要

The thermal performance of an air-to-air thermosyphon heat exchanger has been investigated experimentally. The thermosyphon heat exchanger has been designed and constructed and tested in a test rig under steady state conditions. The lengths of both the evaporator and condensation sections of the heat exchanger were 600 mm and its central adiabatic section was 100 mm. The heat exchanger had 90 plate finned copper thermosyphons arranged in 6 rows. A test rig was constructed and developed wherein the heated air is recycled to evaporator section of THE. The temperature across the evaporator section was varied in the range of 100-250℃. Distilled water was used as the working fluid with a fill ratio of 60% of the evaporator section length. The air face velocity ranged from 0.5 to 5.5 m/s and the heat input into the evaporator section was varied between 18 and 76 kW using electric heating elements. Several experiment were carried out under different operating conditions by varying the parameters in order to determine and investigate their effect on the thermal performance of THE. The experimental overall effectiveness of THE ranged between 37 to 65%.