A review on the use of calcium chloride in applied thermal engineering

• We review the use of CaCl2 in PCM, sorption and thermochemical applications.
• For each application field, CaCl2 exhibits various undesirable behaviours.
• Numerous specific additives have been identified to address these problems.
• The use of CaCl2 as PCM for thermal storage has been widely demonstrated.
• More research is needed for the use of CaCl2 in sorption and thermochemical units.

The combination of its hygroscopy, heat of hydration, the low to medium melting points of its hydrates and its low material costs makes calcium chloride and the respective hydrates an attractive substance for various thermal processes. For refrigeration applications, the ammonia sorption is of high significance. The use of calcium chloride in pure or modified form is reviewed from the application point of view. A short analysis of the general physical and chemical properties highlights the advantageous properties. An overview is given about its use in the following applications: phase change material, desiccant, heat pumps and refrigeration and thermal energy storage. The advantages and challenges are discussed as well as approaches for technical improvement.