A comparison of Borax and TiO2 as nucleating agent for reducing the supercooling of Na2HPO4.12H2O as phase change material

The continuous increase in the level of greenhouse gas emissions and the climb in fuel prices are the main driving forces behind efforts to more effectively use and storage energy. One of the prospective techniques of storing energy is the application of phase change materials (PCMs). Among with the PCMs, one of the best groups are salt hydrates that have the high-energy storage density, relatively high thermal conductivity (almost double of the paraffin’s), and small volume changes during melting. Unfortunately, salt hydrates have some problems such as supercooling which is one of the major problems. This issue can be solved successfully by adding nucleating agents. Two different powders of Borax and TiO2 as nucleating agent were added to Na2HPO4.12H2O (phase change material) to reduce the supercooling effect and the results were studied. The results indicated that TiO2 is more effective than borax to reduce the supercooling of Na2HPO4.12H2O.

کلیدواژه ها:

Phase change material ، salt hydrates ، supercooling ، nucleating agent