Multi-criteria assessment of enhanced radiant ceiling panels using internal longitudinal fins

Abstract

Ceiling radiant cooling panels (RCPs), encapsulating smooth tubes, are the most commonly used terminals in radiant cooling systems. The main limitations of commercial RCPs include low cooling capacity and temperature uniformity. This study proposes a passive enhancement approach by internally finning the copper tubes. Using a validated computational model, the performance of finned RCPs is collaboratively assessed in terms of different performance criteria such as the cooling capacity, temperature uniformity, and hydraulic losses. Triangular, rectangular, and circular fin profiles have been studied for different numbers, aspect ratios, and occupied area fractions of the fins. The results indicate the possibility of boosting the cooling capacity and temperature uniformity by 4.64 and 45.2%, respectively, using 8 triangular fins with an area fraction of 0.3 and an aspect ratio of 2.5. The cooling rate can be enhanced by 27.1% using 12 rectangular fins with an area fraction of 0.3 and an aspect ratio of 2.0. Since various considered performance assessment metrics are in direct conflict, a combined weighted performance index is proposed for design selection. By assuming the cooling capacity, cooling rate, temperature uniformity, and pressure losses to be equally important, a balanced design (12 triangular fins with an area fraction of 0.2 and an aspect ratio of 2.0) can enhance the first two criteria by 1.54 and 17.7%, respectively, while increasing the temperature non-uniformity by 3.7% and the pressure losses by 3.4 folds. However, different weighting factors of the proposed index can be used based on the designer's priorities.