Passive solar cooling with thermoresponsive nanocomposites

The utilization of the water vapor adsorption - condensation - evaporation - desorption cycle with porous thermoresponsive materials for passive solar cooling is analyzed. The recent work in the development, characterization and interaction of solar irradiation with micro- and meso-porous composites of high water vapor adsorption capacity in a wind tunnel of adjustable environmental parameters is presented. The thermal behavior of the developed materials is tested in comparison to natural materials that are used in the external building surfaces. Prior to the tunnel experiments, all materials are characterized with techniques like XRF, XRD, SEM, nitrogen and water vapor adsorption-desorption isotherms, thermal conductivity and reflectance measurements. In cyclic experiments inside the tunnel with simulated solar irradiation, the maximum temperature reduction due to the implementation of the water vapor cycle in the porous material is determined. The utilization of different parts of the solar spectrum for simultaneous multifunctional purposes (like UV-VIS for photodegradation and IR for providing the thermal energy for phase changes) by supporting semiconducting oxides on hydrophilic porous materials, is feasible.