Experimental analysis of temperature uniformity in a vertical smart-farm with radiant cooling panels

Abstract The vertical smart-farm, characterized by multi-layer cultivation structures, predominantly employs a convection cooling system to establish crop growth environments. However, due to the configuration and arrangement of cultivation facilities, cultivation zones are likely to provide non-uniform temperature. Such uneven temperature distribution can lead to non-uniform crop growth and reduced productivity. To address this issue, this study proposes the application of radiant cooling panels, and experimentally verified their effectiveness in improving temperature uniformity. Specifically, a ceiling radiant cooling panel was proposed to establish the growth temperature throughout the entire vertical smart-farm space, while cultivation bed radiant cooling panels beneath each layer were also proposed to mitigate localized temperature increases caused by LED heat generation. To experimentally verify the improvement of temperature uniformity achieved by the proposed ceiling and cultivation bed radiant cooling panels, a mock-up test was conducted. A test cell was constructed by simulating the structure of a vertical smart-farm that actually grows lettuce, and horizontal and vertical temperature uniformity in LED–off and –on states was analyzed. As a result, horizontal temperature uniformity of more than 96% was formed in all layers, the vertical temperature uniformity was more than 95%, and the temperature deviation was within 2 K. Comparison with the results of previous studies applying the convection cooling system showed that the horizontal temperature deviation was maintained at a similar level, while the vertical temperature deviation decreased to about 2/5 ths .