Manipulating the Thermal Conductance by Utilizing Reversible Gas-Solid Reactions

Kurzfassung

The increasing demand for energy-efficient buildings has prompted the development of innovative solutions, including adaptive building envelopes. One such solution is the controllable insulation layer, which has the potential to significantly reduce building energy consumption. The working principle of the controllable insulation layer is to adjust the gas pressure in open-pored insulation panels to control thermal conductivity along an S-shaped curve (Knudsen effect). This can be achieved by using thermochemical materials by precisely setting the temperature of the reaction material and thus the gas pressure can be adjusted reversibly along the equilibrium line. By coupling the thermochemical reaction with an open-pored panel, an insulation system with adjustable thermal conductance is realized. The approach proposed here is based on a thermochemical reactor that serves as an external component outside the panel as a control unit for the gas pressure and thus for the heat flux. The contribution will present a novel design of the thermochemical reactor, along with experimental proof of function as well as an analysis of power demand and dynamics for gas pressure variation in the range of 5 to 1000 mbar. Furthermore, the reactor is coupled with a vacuum insulation panel, and experimental measurements of the thermal behavior of the overall controllable insulation system – consisting of the porous panel and the connected metal hydride reactor component - are presented.