Employing sugar alcohol-based phase change material for integrated compact thermal battery (ICTB): experimental exploration for future configuration of modern space heating with thermal storage

Abstract

Coupling solar space heating (SSH) with thermal energy storage (TES) system is proven to supply clean energy for space heating in building sector. The TES typically employs low-density (< 1 g/cm³) phase change material (PCM) to accommodate maximum temperature operation from the collector. This results in a low-density TES unit, which is less feasible for modern building space heating. The study introduces integrated compact thermal battery (ICTB) using higher density PCM (> 1.4 g/cm³) comes from sugar alcohol group. Temperature limitation is solved by coupling the ICTB with electric heater. The ICTB has an effective volume-to-weight ratio of 0.735 cm³/g, making the model extremely compact as TES tank. The maximum charge temperature is possible to reach 150 °C for sorbitol (SL) and xylitol (XL), while mannitol (ML) achieves higher limit (210 °C). The three PCMs have melting temperature above 90 °C with maximum latent heat of 275.36 J/g. The charge evaluation shows rating charge varies between 38.4–41.1 °C/kWh, which improves about 93.5% by introducing solid stripes. The solid stripe causes suitable temperature distribution inside the ICTB unit without requiring complex system modification. The discharge cycle able to increase the air temperature by 72.6%. This work shows the possibility of achieving higher density TES system for modern space heating using ICTB configuration, providing valuable insight for the advanced development of the system, including the possibility of designing autonomous operations with a high potential for commercialization to support the energy transition in the building sector.