Proceedings of the International scientific and practical conference ―Multidisciplinary approaches in science, technology and culture‖ (September 5-7, 2025) / Publisher website: www.naukainfo.com. – Oxford, United Kingdom, 2025. - 124 p.

120 A sealed nylon tube 1 m long and 2 cm in internal diameter is filled with paraffin T3 (~250 g). The goal is to evaluate: 1. The time required to fully melt the paraffin at an ambient temperature of 30 °C. 2. The amount of thermal energy stored. 3. The duration for which this energy can maintain ambient air at 15–20 °C during cooling. Key parameters : o Volume ≈ 0.00031 m³ o Mass ≈ 0.25 kg (ρ ≈ 800 kg/m³) o Specific heat capacity ≈ 2.1 kJ/(kg·K) o Latent heat of fusion ≈ 190–200 kJ/kg o Melting temperature ≈ 50–55 °C Findings :  At 30 °C, the paraffin does not melt, so only ~5 kJ of sensible heat is stored— insufficient for meaningful heating.  If heated above 50 °C, e.g., to 60 °C by solar radiation, it can store up to 75 kJ (including latent and sensible heat).  The melting process takes ~2–4 hours, depending on heat transfer coefficients and surface area (e.g., h ≈ 5–10 W/m²·K). Discharge performance :  If 75 kJ is released gradually, it can sustain a 10 W thermal load for ~2 hours.  For 10 hours of nighttime heating, at least 5–6 tubes are required (total mass ≈ 1.5 kg paraffin). Conclusion . Paraffin T3 shows practical potential for thermal storage if heated above its melting point, e.g., via solar collectors. Its effectiveness is strongly dependent on system design, especially thermal conductivity and heat exchange surface area. For improved performance, metallic containers or extended surfaces are