Dual-heat-source coupled phase change energy storage heating system
Abstract
This paper presents a phase change energy storage heating system based on the coupling of photovoltaic/thermal and electric auxiliary heating dual heat sources, aiming to meet the demands of clean building heating and electric power peak load shifting. A novel composite phase change thermal storage material was prepared using sodium acetate trihydrate as the main component, with modifications by adding potassium chloride, disodium hydrogen phosphate dodecahydrate, carboxymethyl cellulose, and expanded graphite. Thermophysical property tests show that the material has a phase change temperature of 49.3°C, a latent heat of 224.6 J/g, a thermal conductivity enhanced to 0.981 W/(m·K), and a supercooling degree effectively suppressed to within 1.9°C, making its thermodynamic performance highly suitable for the heating system. Experimental measurements on the test platform demonstrate that the system can accurately switch modes according to the preset logic under various conditions of solar irradiation, grid time-of-use periods, and thermal loads. The charging and discharging processes of the thermal storage device are stable and controllable, and the energy supply output meets the thermal quality requirements of the radiant floor terminals. This study provides a feasible technical solution and material support for low-carbon clean heating and efficient energy management in buildings.