Modeling, simulation and performance analysis of radiant cooling panels operating below the dew point

Global energy demand for space cooling continues to steadily increase, leading to challenges in terms of energy efficiency and sustainability. Surface cooling systems offer advantages regarding energy efficiency but are constrained by an inability to operate below the dew point of room air. Innovative designs address these limitations. Condensation-free radiant cooling panels with fleece and a partially infrared-transparent membrane are one such solution and the focus of this study. This paper presents a modeling approach for these panels and investigates the performance differences compared to a conventional cooling panel.The model accounts for the fleece, air gap, and membrane, but not the capillary tubes and cooling fluid. The thermal conductivity of the fleece was unknown and determined experimentally. The ISO 15099 thermal glazing model was adapted and implemented in TRNSYS to evaluate thermal comfort and cooling capacity. Measurements on below dew-point-panels under different conditions were compared to simulation results, showing the model accurately describes the thermal behavior. Simulations provide layer temperature data unobtainable through direct measurement. A simulation study assessed performance in various climates and development potentials. Using below-dew-point panels in warm, humid climates with natural ventilation offers great potential to reduce air conditioning energy demand. The study also suggests performance improvements by optimizing the system's structure.