Yue Liu,Tianen Chen,Xinyu Song,Lin Han,Fanbin Meng,Shifeng Wang
Energy is indispensable in modern society. Solar Photovoltaic (PV) technology has gained increasing popularity due to its notable power generation advantages. However, PV modules face a critical “temperature-efficiency” contradiction during energy conversion: only about 20% of solar radiation is converted into electricity, while the remaining energy accumulates as heat, leading to significant performance degradation. To address this issue, our experiment employs a novel cooling technology-phase-change microcapsule cooling. By utilizing the heat absorption and release during the phase transition of the microcapsules, the temperature of PV modules is effectively regulated. Furthermore, the phase-change microcapsules designed in this work innovatively introduce paraffin as a secondary shell material, which improves thermal cycling stability. After 200 thermal cycles, the enthalpy loss remains negligible, with a retained enthalpy of 188.8 J/g. The microcapsules were applied to the back of PV modules, and field tests were conducted in Lhasa (91°06′ E, 29°36′ N). The results show a maximum temperature reduction of 16 °C (average: 4.66 °C) on the front side and 15 °C (average: 4.33 °C) on the back side, along with an increase in Pmax (P max ) of up to 11.11% (average: 4.55%). This study not only advances the development of bio-inspired encapsulation techniques for novel phase-change microcapsules, but also provides an innovative thermal-management solution for PV modules operating in extreme environments.
Qi Honghua,Zhang Ting,Zhang Deyi,Wang Kunjie,Wang Yi
To study the effects of emulsifier content on the structure and thermal properties of encapsulated phase change materials (PCMs), four kinds of paraffin/chitosan (CS) macroencapsulated PCMs with different emulsifier contents were fabricated via the piercing–solidifying method. The effects of emulsifier content on macro-profile, micromorphology, thermal energy storage properties, and thermal durability of the as-prepared composite, as well as the structure of the optimal capsules, were investigated. The results show that the non-spherical degree, average diameter, and compressive strength decreased first and then increased with increase in emulsifier content, resulting in thermal energy storage capacity’s increase at first and then its decrease. The optimal macro-capsules, fabricated at the critical micelle concentration of the emulsifier, present a regular spherical surface and microencapsulated paraffin wax inside. The paraffin content is as high as 85%, with a phase change latent heat of 112.6 J g −1 for melting and 118.7 J g −1 for solidification. The melting enthalpy and weight loss ratio of the optimal paraffin/chitosan composite after 600 heating/cooling cycles only changed to 0.71% and 1.17%, respectively. These results not only suggest that the piercing–solidifying method can be employed to fabricate macro-capsules with high heat storage performance and excellent thermal stability but also reveal that paraffin/CS can be used in thermal management at low temperature.
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