Thermochemical　heat-storage　materials,　e.g.,　magnesium,　zinc　and　iron　sulfates,　offer　high　energy-storage　densities　and　a　reliable　means　of　long-term　storage　of　solar　energy.　The　dynamic　properties　of　these　three　salts　were　studied　based　on　their　hydration　and　dehydration　characteristics.　The　effect　of　regeneration　temperatures　on　the　physio-chemical　properties　of　the　materials　was　evaluated　using　four　sets　of　temperatures.　At　100°C,　zinc　sulfate　showed　a　significant　loss　of　water　as　compared　to　magnesium　and　iron　salts,　while　in　the　hydration　process　at　lower　temperatures,　zinc　sulfate　showed　the　highest　sorption　enthalpy　and　energy　density.　Also,　the　crystallinity　of　salt　hydrates　was　characterized　using　powder　X-ray　diffraction　measurements,　which　revealed　that　dehydration　of　water　molecules　occurred　only　in　magnesium　sulfate,　while　partial　distortion　occurred　in　iron　sulfate　with　an　increase　in　temperature.　Collating　the　results　together　suggested　that　zinc　sulfate　is　more　energy　efficient　than　both　magnesium　and　iron　sulfate.　With　a　calculated　hydration　energy　density　at　100°C　of　1.26 GJ/cu　m　zinc　sulfate　is　the　best　option　among　the　three　salts　for　its　use　as　a　thermochemical　material.