**1. Introduction**

One solution to fully exploit renewable energy in residential heating is to develop a technology by which the thermal energy received by the sun could be directly stored during the day and released whenever needed. Doing so would result in a significant reduction in the residential share of fossil fuel consumption and CO2 emissions while providing residential heating. The key factor to attain such goal lays in finding suitable substances capable of storing high level of thermal energy and efficiently substituting them in a residential thermal system.

In recent years, zeolite 13X has received considerable attention to be used as an efficient heat storage substance in thermal systems. Due to its special molecular structure, which contains well-defined microchannel and cavities, zeolite 13X can store heat by removing humidity and release heat when humidity is introduced to the compound, which gives zeolite 13X a unique heat storage property. The stored heat will be confined as long as no humidity is introduced to the system. This feature provides a simple, safe, and affordable mechanism for portable thermal energy. Despite these unique features, Thermal Energy Storage (TES) systems containing zeolite13X have not yet acquired a significant share in residential heating due to their poor operating performance for the sector.
