Performance Investigation of the Novel Solar-Powered Dehumidification Window for Residential Buildings

In this paper, a solar-powered dehumidification window (SPDW), combining a conventional double-glazed building window with a solid desiccant packed bed and a photovoltaic panel, has been proposed to dehumidify the air supplied to a residential building in an energy-saving way. The solid desiccant packed bed was installed between the double layers of the residential window to achieve the compact building-integrated window-dehumidifying system that could be regenerated by solar energy, and the photovoltaic panel was used to compensate the electricity for the operation of the fans to supply the air to the building. To investigate the dehumidification and regeneration performance of the SPDW, the transient moisture removal, dehumidification efficiency, temperature difference between the building inlet and outlet air, heat transfer characteristics, desiccant temperature, regeneration rate, and the power of the fans and the photovoltaic panel were analysed for different inlet air conditions and simulated solar radiation. It was found that, for the system operated under an inlet air temperature of 19.2 ◦C and a relative humidity of 86.1% during the dehumidification process, the system performed with a maximum transient moisture removal of 7.1 g/kg, a maximum dehumidification efficiency of 58.60%, a maximum temperature difference between the inlet and outlet air of 10.7 ◦C, and a maximum released adsorption heat absorbed by the dehumidified air of 89.66%. In the regeneration process, the system performed with a maximum desiccant temperature of 35.3 ◦C, a maximum regeneration rate of 153 g/h, and a maximum power of the photovoltaic panels of 39.83 W under the simulated solar radiation of 900 W/m2. The results from the established semi-empirical model agreed well with the testing results, and the model could be used to predict the water content ratio of the desiccant modules during the dehumidification process under different conditions, which will be helpful in the analysis and application of the SPDW in the future.