Evaluation of stearic acid/coconut shell charcoal composite phase change thermal energy storage materials for tankless solar water heater
| Autor: | Lixin Yang, Chuanchang Li, Bo Zhang, Guiyu Xiao, Baoshan Xie, Jian Chen |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment business.industry Composite number Transportation Building and Construction H2O2 modification Thermal energy storage Phase-change material Phase change materials lcsh:TD1-1066 lcsh:TH1-9745 Thermal conductivity Chemical engineering Latent heat Coconut shell charcoal Surface modification Thermal stability lcsh:Environmental technology. Sanitary engineering business Tankless solar water heater Thermal energy Civil and Structural Engineering lcsh:Building construction |
| Zdroj: | Energy and Built Environment, Vol 1, Iss 2, Pp 187-198 (2020) |
| ISSN: | 2666-1233 |
| Popis: | This work presents a cost-effective and environment-friendly form-stabilized phase change material (PCM) and corresponding solar thermal application in the tankless solar water heater (TSWH). Coconut shell charcoal (CSC) as supporting material was modified by moderate oxidant of H2O2 with different concentrations, and then stabilized stearic acid (SA) to prepare composite PCMs through vacuum impregnation. It found that CSC support causes a 15.70% improvement of SA loadage after treated by 15% H2O2 due to coefficient enhancement by physical interaction and surface modification. The modified CSC15 support appears more super macropores which contribute to the impregnation of SA than non-modified CSC0 support verifying from SEM and BET results. And the content of oxygen functional groups was increased after oxidation modification, also motivating SA stabilization by hydrogen bond interaction in XPS analysis. FTIR results proved there is no chemical reaction happened between SA and CSC. Moreover, the latent heat and phase transition temperature of the as-prepared SA/CSC15 composite are 76.69 J g−1 and 52.52 °C, respectively. All composites exhibit excellent thermal stability under a working temperature of 180 °C and form stability during phase change. Thermal energy storage-release test within 70 °C presents the composite has fast heat transfer efficiency than pure SA. The composite filled in TSWH system has 0.75 W m−1 K−1 thermal conductivity which is 2.88 times higher than that of pure SA (0.26 W m−1 K−1). Besides, the TSWH system with a flow rate of 0.004 kg s−1 could heat water effectively after sunset and the energy obtained from the thermal storage system within 1830 s testing times is about 0.15 kW h. In all, SA/CSC composite with good physical-thermo properties has potential in thermal energy storage application, especially in solar energy storage. |
| Databáze: | OpenAIRE |
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