Phase change materials for thermal energy storage

Organic phase change materials and their textile applications: An overview

Enhance heat transfer for PCM melting in triplex tube with internal-external fins

Internal and external fin heat transfer enhancement technique for latent heat thermal energy storage in triplex tube heat exchangers

The continuous increase in the level of green-house gas emissions and the depletion of fossil ‎fuels are identified, as the major driving forces behind efforts to effectively utilize different sources of renewable energy. Solar energy ‎considered one of the most prospective sources of this energy. This review paper mainly focuses on the majority of heat-transfer enhancement techniques between the phase-change material (PCM) and the heat-transfer fluid (HTF) based on the application of fins embedded in the PCM. This study ‎also investigated the geometrical dimensions, dimensionless numbers, and fin location through numerical ‎and experimental works conducted to assess the influences of these parameters on the thermal performance of PCM-latent heat thermal energy storage (LHTES) containers. The best enhancement is ‎achieved using the longitudinal finned configurations because of its easy design and fabrication, especially along circumference of the cylindrical PCM containers. The circular-finned tube was also more effective than the pinned-tube for different shell and tube. PCMs based on heat sinks with internal pin fins were widely used for the thermal ‎management of various pieces of electronic products. The heat enhancement factor was effectively dependent on increasing the numbers and dimensions ‎of these fins. Further researches still require to explore the ‎possible geometrical designs of fins and their key findings, which have more effect on the thermal performance of the ‎finned-LHTES system.

Geometric and design parameters of fins employed for enhancing thermal energy storage systems: a review

Numerical simulation on phase-change thermal storage/release in a plate-fin unit

Phase change materials (PCM) have been extensively scrutinized for their widely application in thermal energy storage (TES). Paraffin was considered to be one of the most prospective PCMs with perfect properties. However, lower thermal conductivity hinders the further application. In this letter, we experimentally investigate the thermal conductivity and energy storage of composites consisting of paraffin and micron-size graphite flakes (MSGFs). The results strongly suggested that the thermal conductivity enhances enormously with increasing the mass fraction of the MSGFs. The formation of heat flow network is the key factor for high thermal conductivity in this case. Meanwhile, compared to that of the thermal conductivity, the latent heat capacity, the melting temperature, and the freezing temperature of the composites present negligible change with increasing the concentration of the MSGFs. The paraffin-based composites have great potential for energy storage application with optimal fraction of the MSGFs.

The investigation of thermal conductivity and energy storage properties of graphite/paraffin composites

Fluid flow and heat transfer in a latent thermal energy unit with different phase change material (PCM) cavity volume fractions.

The flow and thermal behavior of the phase change material in a novel geometry, namely, quadrantal cavity, is investigated numerically. The influences of curved wall temperatures of 32, 37, and 42 °C, the initial sub-cooling temperatures of 5, 10, and 15 °C which are lower than ambient temperature, are examined previously. Inclination angles for the range from 0 to 360° on flow and thermal performances are carefully studied. It is found that the inclination angles affects dramatically not only the time of complete thermal energy storage but also convection currents. The best performance is obtained for an inclination angle of 225°.

Effect of the inclination angles on thermal energy storage in a quadrantal cavity

The invention discloses a heat transfer enhanced heat pump phase-change heat storage device, which mainly comprises supporting plates (5), a plurality of independent harmonica plate plate-type heat exchangers (6), fins (2), a liquid collection header pipe and a liquid collection pipe, wherein one of the harmonica plate plate-type heat exchangers (6) is arranged between each two supporting plates (5); the fins (2) are arranged between the harmonica plate plate-type heat exchangers (6) and the supporting plates (5); a phase-change heat storage material (15) is filled in gaps among the harmonica plate plate-type heat exchangers (6), the supporting plates (5) and the fins (2); the harmonica plate plate-type heat exchangers (6) consist of harmonica plate sheet units extruded with a plurality of flow passages (14); and outlets and inlets of the flow passages (14) are in brazed connection with the liquid collection pipe, and then are communicated with the liquid collection header pipe through the liquid collection pipe. The heat transfer enhanced heat pump phase-change heat storage device realizes the storage and the release of heat through the heat exchange between the heat exchangers and the phase-change heat storage material, and forms a heat pump phase-change heat storage device integrated with heat storage and heat supply. The heat pump phase-change heat storage device has the advantages of small volume, light weight, simple structure, low cost, low power consumption, safety, reliability and the like.

Nan Wang

Papers

Numerical simulation on phase-change thermal storage/release in a plate-fin unit

The investigation of thermal conductivity and energy storage properties of graphite/paraffin composites

Fluid flow and heat transfer in a latent thermal energy unit with different phase change material (PCM) cavity volume fractions.

Effect of the inclination angles on thermal energy storage in a quadrantal cavity

Heat transfer enhanced heat pump phase-change heat storage device