Thermochemical　heat　storage　materials　for　space　heating　applications　such　as,　ZnSO4　offer　high　energy　storage　density,　low　cost　and　clean　mean　of　long-term　solar　energy　storage.　Herein,　we　studied　the　ZnSO4　hydrated　salt　as　potential　heat　storage　material　at　low　temperature　and　furthermore　observed　the　impact　of　temperature　and　concentration　on　the　dehydration/hydration　process　and　enthalpy.　The　thermal　behavior　of　ZnSO4•7H2O　was　investigated　by　applying　various　dehydration　temperatures.　The　results　showed　that　85%　of　water　loosed　at　100 °C　temperature,　which　released　699 J/g　(1.37　GJ/m3)　in　the　dehydration　process.　The　hydration　process　of　ZnSO4.7H2O　at　100 °C　recovered　541 J/g　enthalpies,　which　delivered　1.1　GJ/m3.　Similarly,　the　dehydration　result　obtained　at　150 °C　was　the　same　as　showed　at　100 °C.　However,　the　enthalpy　of　hydration　was　20%　less　than　prior.　The　XRD　result　showed　that　at　higher　temperatures　agglomeration　appeared　followed　by　Van　der　Waals　forces　which　affect　the　hydration　rate.　The　result　of　good　cyclability　and　larger　water　sorption　performance　of　ZnSO4　make　them　a　promising　and　suitable　for　heat　storage　in　space　heating　application,　which　can　be　used　as　thermochemical　heat　storage　material　for　thermal　storage　devices.　©　2020,　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.