Sodium Sulhate in heat storage by Laxmi Enterprise, Vadodara, Gujarat, India.

Sodium Sulphate Decahydrate (Na₂SO₄·10H₂O) — also called Glauber’s Salt — is used for thermal energy storage (TES) and how the process works scientifically and industrially. 🔷 1. Introduction: What is Sodium Sulphate Decahydrate (Glauber’s Salt)? Chemical formula: Na₂SO₄·10H₂O Common name: Glauber’s Salt Molecular weight: 322 g/mol Melting point: ~32–33°C Latent heat of fusion: ≈ 254 kJ/kg This high heat of fusion makes it excellent for storing and releasing thermal energy — particularly in phase change material (PCM) systems for low-temperature thermal energy storage. 🔷 2. Concept: How Thermal Energy Storage (TES) Works In TES systems using phase change materials (PCMs), the material absorbs heat when melting and releases heat when solidifying — without a large change in temperature. Example: When Glauber’s salt melts (solid → liquid) at 32°C: Na₂SO₄ cdotp 10H₂O (solid)    → heat absorbed    Na₂SO₄ (aqueous) + 10 𝐻 2 𝑂 Na₂SO₄cdotp10H₂O (solid) heat absorbed ​ Na₂SO₄ (aqueous)+10H 2 ​ O This process stores energy as latent heat. When the system cools: Na₂SO₄ (aqueous) + 10 𝐻 2 𝑂    → heat released    Na₂SO₄ cdotp 10H₂O (solid) Na₂SO₄ (aqueous)+10H 2 ​ O heat released ​ Na₂SO₄cdotp10H₂O (solid) The salt crystallizes, releasing stored heat at almost constant temperature (~32°C). 🔷 3. Step-by-Step Working Process Step 1: Charging (Heat Storage) When the ambient or supplied temperature rises above 32°C, Glauber’s salt melts. During melting, it absorbs heat energy from the environment (e.g., solar collectors or hot air). The material becomes a liquid solution — storing energy as latent heat of fusion. Step 2: Storage Phase The molten Glauber’s salt is stored in insulated containers (often in steel or HDPE tanks). It stays stable for several hours to days, maintaining its temperature near the melting point. Step 3: Discharging (Heat Release) When the temperature drops below 32°C, the solution starts crystallizing back to solid decahydrate. The latent heat is released in this phase, providing warmth to the surroundings. This energy can be used for: Space heating Drying operations Greenhouse heating Domestic hot water preheating 🔷 4. System Design Example (Simplified) Component Purpose PCM tank (Glauber’s salt) Stores the heat Heat exchanger tubes Transfers heat in/out Solar collector / Electric heater Provides input heat Insulation layer Minimizes losses Water or air circulation Transfers useful heat to application 🔷 5. Advantages of Glauber’s Salt as PCM ✅ High latent heat capacity → stores large amounts of energy per unit mass. ✅ Stable phase change temperature (32°C) → ideal for comfort heating. ✅ Inexpensive & non-toxic → readily available and environmentally safe. ✅ Good thermal conductivity compared to organic PCMs like paraffin. 🔷 6. Challenges & Modifications Despite its benefits, raw Glauber’s salt has some issues: Issue Explanation Solution Phase separation Water separates after multiple cycles Add thickening agents (e.g., sodium carboxymethyl cellulose, bentonite) Supercooling Crystallization delayed Add nucleating agents (e.g., borax, Na₂B₄O₇·10H₂O) Volume change Expansion during melting Design flexible storage containers By adding stabilizers, Glauber’s salt becomes reliable for hundreds of heat–cool cycles. 🔷 7. Industrial & Commercial Applications Application Use of Sodium Sulphate Decahydrate Solar water heating Stores heat during the day, releases at night Building HVAC systems Thermal regulation for walls or ceilings Refrigeration backup Maintains cold chain stability during power outages Greenhouses Keeps temperature stable for crops Thermal energy recovery systems Stores waste heat from industrial exhausts 🔷 8. Energy Example Calculation For 1 kg of Glauber’s salt: Latent heat = ~254 kJ/kg So, 10 kg can store ≈ 2540 kJ (≈0.7 kWh) of thermal energy at 32°C. That’s enough to maintain a small room’s temperature for several hours. 🔷 9. Summary of Benefits Property Value Importance Melting point 32–33°C Ideal for space heating Latent heat 254 kJ/kg High storage density Reusability 100s of cycles Long operational life Cost Low Economical PCM Safety Non-toxic Environment-friendly Sodium Sulhate in heat storage by Laxmi Enterprise, Vadodara, Gujarat, India. • Sodium Sulphate for Sale • Sodium Sulphate Supplier • Sodium Sulphate Manufacturers • Sodium Sulphate Exporter • Sodium Sulphate Powder • Industrial Grade Sodium Sulphate • Anhydrous Sodium Sulphate • Sodium Sulphate Bulk Supply • Sodium Sulfate Distributor