Experimental Results of a 1 kW Heat Transformation Demonstrator based on a Gas-Solid Reaction

Abstract

Heat transformation based on reversible chemical reactions has gained significant interest due to the high achievable output temperatures. These chemical heat pumps use a reversible gas-solid reaction in which the back and forward reaction take place at different temperatures: by running the discharge reaction at a higher temperature than the loading reaction, the released heat is thermally upgraded. In this work, we report on the experimental investigation of a salt hydrate with regard to its use for heat transformation in the temperature range from 180 °C to 300 °C on a 1 kW scale. The reaction temperature is set by adjusting the pressure of the gaseous reactant, water vapor, in a range from 1 kPa up to 0.6 MPa. In our prior experimental studies, we found the properties of the solid bulk phase to be subject to considerable changes due to the chemical reaction: amongst others, the particle size distribution shifts, resulting in agglomeration and altered bulk permeability. In order to better understand how this affects the thermal performance of a thermochemical reactor, we combine our experimental work with a modelling approach. Our current work includes the development of a reactor concept that allows handling gas-solid reactions at high specific thermal powers as well as an easy scale-up for industrial applications.