A study of novel high performance and energy dense zeolite composite materials for domestic interseasonal thermochemical energy storage

Thermochemical Energy Storage (TCES) materials can be used to store and release thermal energy during times of high demand for applications such as Domestic Space Heating (DSH) or Domestic Hot Water (DHW). Novel composite materials have been created by 2 methods, i) impregnating zeolites with MgSO4 using a modified wetness impregnation method and ii) forming zeolites impregnated with MgSO4 into 4mm pellets using a pellet preparation method and a binder, these composite pellets have been named ZMK. Differential Scanning Calorimetry (DSC) measurements were used to assess the composite materials energy density and performance ratio. The ZMK pellets were also tested on a larger (200g) scale using an in-situ open fixed bed reactor. It was found that ZMK dehydrates at a temperature of 150˚C with a dehydration enthalpy of 715 J/g, with an overall performance ratio of 85% at a 10mg scale. ZMK was found to have a volumetric energy density of 415MJ/m3 and a specific energy density of 702J/g at a 200g scale when hydrated (discharged) with 68% RH air at 20˚C, making it a suitable candidate for interseasonal TCES.