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The thermal energy storage technology based on phase change materials (PCMs) can solve the mismatch problem between thermal energy supply and demand, and improve energy utilization efficiency. However, the fluid leakage problem and low thermal conductivity of PCMs are not suitable for solar thermal storage application. The solar thermal collector combined with PCM seeks for the rapid storage of thermal energy and reduces the heat exchange with external environment, requiring PCM to possess specific directional thermal conduction. In this paper, inspired by the principle of directional transport of water in the cellulose channel of natural trees, the porous structure with anisotropic thermal conductivity is formed by carbonization of pine at 1000 °C. The CPCM with directional thermal conductivity is prepared by combining magnesium nitrate hexahydrate (MNH) with carbonized wood (CW). The axial thermal conductivity of the MNH/CW composite PCM (CPCM) is 1.86 times than that of the radial direction. The photo-thermal conversion efficiency of MNH/CW CPCM is 83%. This structure changes the direction of thermal energy transmission, and reduces the dissipation of thermal energy and the use of thermal insulation medium. This work provides an innovative idea for the design and manufacture of CPCM related to low and medium temperature solar thermal energy storage. • The anisotropic thermal conductivity structure of CW is formed by carbonization. • The axial thermal conductivity is 1.86 times than that of radial direction. • The photo-thermal conversion efficiency of CPCM is 83%. [ABSTRACT FROM AUTHOR]

China implemented the Promoting the Big and Quashing the Small Policy (PBQSP) in 2007 to alleviate air pollution due to coal-fired power plants (CFPPs). However, how the policy affected the air pollutant emissions remains poorly understood. We compared the air pollutant emissions between decommissioned and newly-built CFPPs under the PBQSP by developing a plant-level supply chain emission inventory model, taking Shandong, China's top provincial-level coal power producer, as the case area. The results indicated that compared to a 27.4% increase in electricity produced in Shandong from 2010 to 2014, the NOx, particulate matter (PM), Hg, and SO 2 emissions disproportionately increased by 10.3%, 11.7%, 11.8% and 0.5%, respectively. It was found that the PBQSP policy has made great contribution to air pollution mitigation, as the supply chain emission intensities (emissions per kilowatt-hour) of NO X , PM, Hg and SO 2 of the newly-built CFPPs are three-quarters, two-fifths, three-fifths, and four-fifths lower, respectively, than those of the decommissioned CFPPs. However, coal transport route changes caused an increase in NO X , PM, and SO 2 emissions by 44.0%, 45.5%, and 55.6%, respectively, during the transportation stage, which offset the PBQSP overall mitigation effect. By building a comprehensive assessment framework for air pollutant control policies, our study provides insights for formulating coordinated mitigation measures for the pollutant-intensive industries, such as promoting efficient air pollutant control technologies including the spray dust suppression devices. • A supply chain emission inventory model was built to assess the mitigation effect. • Technological improvement led to the decline of the emission intensity. • The coal transport route changes resulted in a net increase in air pollutants. • Policy implications for comprehensive pollutant mitigation were recommended. [ABSTRACT FROM AUTHOR]