Feasibility study of MgSO₄ + zeolite based composite thermochemical energy stores charged by vacuum flat plate solar thermal collectors for seasonal thermal energy storage

A primary drawback of solar thermal technologies, especially in a domestic setting, is that collection of thermal energy occurs when solar irradiance is abundant and there is generally little requirement for heating. Thermochemical Energy Storage (TCES) offers a means of storing thermal energy interseasonally with little heat loss. A combination of a Solar Thermal Collector (STC) and TCES system will allow a variety of different heating applications, such as domestic space and hot water heating as well as low temperature industrial process heat applications to be met in a low carbon way. This paper describes and assesses the feasibility of two novel technologies currently under development at Loughborough University; i) an evacuated flat plate STC and ii) composite TCES materials, coupled together into a system designed to store and supply thermal energy on demand throughout the year. Experimental results of composite TCES materials along with predicted performance of STC's are used within a developed model to assess key metrics of conceptual TCES + STC systems feasibility, including; charging time, payback time, cost/kWh, energy savings and CO2 savings. This paper demonstrates the economic, energy and carbon savings potential of conceptual TCES + STC systems suitable for domestic use.