Thermal resistances of the ceiling radiant cooling panels with an inbuilt air gap (AGP) are large, which are mainly contributed by the air gap and the radiation shield. Replacing the radiation shield (metal plate) with the convection shield (IR semi-transparent film), thermal resistances can be reduced. In this study, thermal resistances of previous AGPs are analyzed using the experimental data from published literature, and validated lumped parameter thermal models are used to compare thermal performance of the previous and improved AGPs. The results show that the improved AGP with 6 mm air gap can provide 124.2 W/m(2) cooling capacity when the cold surface temperature is 7 degrees C. Under the same steady-state condition, cooling capacities are increased by 48.1% and 18.5% when compared with the previous AGPs with 6 mm air gap and 1 mm air gap, respectively. Meanwhile, the temperature of the IR semi-transparent film is 1.18 degrees C higher than the dew point temperature. The improved AGP has a better synergy in improving cooling capacity and anti-condensation ability. It is recommended that future research pay more attention to the convection shield with high IR transmissivity and excellent mechanical properties rather than the air gap.
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