H. A. Zondag1*, Alex Kalbasenka1, Martijn van Essen1,

Lucas Bleijendaal1, Roelof Schuitema1, Wim van Helden1, Lucienne Krosse2

1 ECN, Energy Research Centre of the Netherlands, P. O. Box 1, 1755 ZG Petten, The Netherlands
2TNO, P. O.Box 342, 7300 AH, Apeldoorn, The Netherlands
* Corresponding Author, Zondag@ecn. nl

Abstract

This paper summarises the findings of a parameter study on a TCM reactor, and in addition presents first calculations on the dimensioning of three concepts for dehydration reactors.

1. Introduction

Traditional heat storage techniques have a number of disadvantages for long-term heat storage, such as substantial heat loss and relatively low energy density (large volume). As an alternative, it is possible to store energy by means of chemical processes in thermochemical materials (TCM), making use of the reversible chemical reaction A(s) + B(g) О C(s) + heat. Interesting reactants are low cost, non-toxic, non-corrosive, have sufficient energy storage density and have reaction temperatures in the proper range. These requirements are fulfilled by a number of salt hydrates. In a previous study (Visscher et al., 2004), magnesium sulphate has been identified as a potentially interesting storage material, by means of the reaction MgSO4(s) + 7H2O(g) О MgSO4x7H2O(s) + 411 kJ per mole of MgSO4. This material could be interesting for seasonal storage of solar heat. During winter, when heat is needed for e. g. residential heating, the magnesium sulphate is hydrated, producing heat. During summer, the hydrate is dehydrated by heat from a solar collector, which can be regarded as charging of the material. Once the chemical reaction has taken place, the solar heat can be stored in this way for a long time period without losses.