Optimizing cooling performance of infrared transparent condensation-free radiant cooling by using bubble wrap

Radiant cooling system has well acknowledged as one of high-performance air conditioning techniques for the energy-saving and thermal comfort. However, it faces the defects of easy condensation and limited cooling capacity in hot and humid climates. Herein, aiming at improve condensation-free safety and cooling capacity, a novel radiant cooling panel covered by using bubble wrap was proposed. Firstly, a reduced-scall experiment on the cooling performance of the radiant cooling by using bubble wrap was conducted. Secondly, a three-dimensional transient heat transfer model of the bubble wrap assisted cooling panel was established and validated with the experimental results. Thirdly, by using the model the orthogonal investigation was conducted by using various bubble geometric parameters such as bubble height (H), diameter (D), and spacing (L). The effects of the bubble geometric parameters on the cooling performance of the radiant cooling panel were explored. Finally, aiming at greater cooling capacity and higher condensation-free safety, the optimization of the bubble geometric parameters was conducted for the design of the radiant cooling panel. The results indicated that the optimal combination of bubble geometry parameters could be H = 5 mm, D = 5 mm, L = 20 mm aiming at the maximum cooling capacity of 127.24 W/m². For the application of the radiant cooling panel in humid environment, the optimal combination of bubble geometry parameters could be selected as H = 20 mm, D = 15 mm, L = 5 mm for maintaining a higher air contact surface temperature to avoid condensation. It demonstrated the potential of the bubble wrap being used in high performance cooling panel in humid environment.