Low temperature heat storage with phase change materials

Abstract

A group of promising phase change heat-storage materials was selected through study of the literature, laboratory tests of freeze—melt behaviour and determination of thermophysical properties. Means were developed of encapsulating these materials in metal or plastic containers. Four of these phase-change materials, suitably encapsulated, were tested in a sub-kale thermal storage unit of about 20MJ capacity, using air as the heat-transfer fluid. In most cases, measured thermal-storage capacity exceeded 90% of the theoretical value. After considering a number of heating and cooling schemes employing phase-change heat storage, we selected a forced hot air, central storage design, using CaCl₂.6H₂O encapsulated in plastic pipes. A home was designed, using a two-storey conservatory for solar collection with vertical glazing and movable insulation.