Simulation study of a pipe-encapsulated PCM wall system with self-activated heat removal by nocturnal sky radiation.

Pipe-encapsulated PCM wall system with self-activated heat removal by nocturnal sky radiation cooler is a feasible means for building insulation and heat removal by using natural energy. In this paper, a system simulation platform including the simplified pipe-encapsulated PCM wall model, heat pipe heat-transfer model and nocturnal radiation model are established to investigate the thermal performance of the pipe-encapsulated PCM wall system with self-activated heat removal by a nocturnal sky radiation cooler. The temperature and heat flow of this system used in light-weight, medium-weight and heavy-weight walls under a dynamic boundary condition are respectively simulated on this platform. Results show that about 55.6%–82.8% of heat from the outdoor can be resisted by the pipe-encapsulated PCM wall, and 54.7%∼81.0% of that can be removed by the nocturnal radiation cooler at night. Comparing with the common wall, the proposed system can reduce by 32.4%∼55.5% of the accumulated heat entering into indoor environment. Good energy-saving potential can be achieved by this pipe-encapsulated PCM wall system. Besides, the result further reveals that the reduction of the accumulated internal surface heat transfer of this system used in medium-weight and heavy-weight walls is obvious larger than that of this system used in light-weight wall. • System platform of a pipe-encapsulated PCM wall system with heat removal. • Thermal performance of three walls (light, medium, heavy) with the PCM wall system. • 55.6%–82.8% of heat from the outdoor can be resisted by the PCM wall system. • Reduction of heat into the indoor is lager for the heavy wall with the PCM system. [ABSTRACT FROM AUTHOR]