An Experimental Investigation of Increasing the Thermal Efficiency of a Finned Tube Heat Exchanger by Using the Chimney Effect

In the paper, experimental analyses of free convection heating transfer in a flat wavy-fin heat exchanger with dimensions 500 × mm were investigated. The reserch mainly included determining average flux and heat-transfer coefficient for two selected types finned exchangers. First, tests conducted exchangers without considering so-called ’chimney’ effect; these will be treated as reference studies. Then, experiments specially designed ’chimneys’ over heights 350, 850, 1350 mm, respectively, carried out again. performed an temperature difference between heat-exchange surface environment range 18 to 55 K. results demonstrated that, compared chimney, addition chimney significantly affects improvement thermal performance under natural conditions. Regarding variant when is used highest height maximum K, increases by approximately 450% 10 times higher. characterised lower airflow resistance showed higher values 5 45% Rayleigh number 25 180. Studies have indicated that some cases, simple modification geometry leads significant improvements and, extreme elimination supporting equipment such fans.