ECN publication
Characterization of salt hydrates for compact seasonal thermochemical storage
Published by: Publication date:
ECN Efficiency & Infrastructure 25-11-2009
ECN report number: Document type:
ECN-M--09-101 Conference Paper
Number of pages: Full text:
6 Download PDF  

Presented at: Energy Sustainability 2009, San Francisco, USA, 19-23 juli 2009.

This paper describes the characterization of four salt hydrates as potential thermochemical material for compact seasonal heat storage in the built environment. First, magnesium sulfate was investigated in detail using TG-DSC apparatus. The results of this study revealed that magnesium sulfate is able to store almost 10 times more energy than water of the same volume. However, the material was unable to take up water (and release heat) under practical conditions. A new theoretical study identified three salt hydrates besides magnesium sulfate as promising materials for compact seasonal heat storage: aluminum sulfate, magnesium chloride and calcium chloride. These salt hydrates (including magnesium sulfate) were tested in a newly constructed experimental setup. Based on the observed temperature lift under practical conditions, it was found that magnesium chloride was the most promising material of the four tested salt hydrates. However, both calcium chloride and magnesium tend to form a gel-like material due to melting or formation of a solution. This effect is undesired since it reduces the ability of the material to take up water again. Finally, it was observed that performing the hydration at low-pressure will improve the water vapor transport in comparison to atmospheric pressure hydration.

Back to List