Air flow and thermal efficiency characteristics in solar chimneys and Trombe Walls

This paper reports on an experimental investigation into heat transfer and mass flow in thermosyphoning air heaters, such as solar chimneys and Trombe Walls. The test rig comprised a vertical open-ended channel with closed sides, resembling a solar collector or solar chimney approximately 1 m2. Close control of the heat input was achieved by using an electrical heating mat—steady-state heat inputs ranged from 200 to 1000 W, and the channel depth was varied between 20 and 110 mm. Temperatures were recorded throughout the test rig, as was the air velocity. The principal results from the data showed: