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Numerical Simulation of Heat Transfer Characteristics of Capillary Radiant Heating Floor
Shenghua Fu,Yang Pan,Xingping Wan,Jiyue Wang,Xiaofeng Jia,Xinmei Luo,Hongqiang Ma 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2
In order to study the temperature transference characteristics of capillary radiant heating ground, a glowing temperature change flooring model is typically established to analyze the influence of different factors on the heat transfer characteristics of the heating system. The results show that the distribution of covering temperature is uneven in the radiant heating system, and the fluctuation amplitude increases with the increase of the pipe spacing. At the same time, the change of the surface temperature is further analyzed for the finishing layer material on the radiant heating storey. The results show that the change of the capillary tube spacing leads to a smaller change in the floor exterior temperature when the wood floor is used as the finishing layer. It accurately indicates that the wood floor as the finishing layer can allegedly provide a more balanced surface temperature. Finally, the effects of finishing the layer, filling layer material and pipe spacing are studied for the change of surface heat flux. The results show that the heating effect of 30°C quandary in capillary radiant heating system can merely reach that of 40°C hot water in heating structure with traditional pipe breadth when the finishing layer universally adopts floor tiles and the capillary pipe diameter is 10 mm. This suggests that the thin system can use low-temperature hot water for effective energy-saving heating. The above research results can thoughtfully provide theoretical guidance for radiant floor heating.
Hongwei Lu,Jianxin Du,Cuiping Yu,Xingping Wang,Yanlin Gao,Weizhong Xu,Aiping Liu,Xiaoxiao Lu,Yingxin Chen 한국고분자학회 2020 Macromolecular Research Vol.28 No.6
The development of high dielectric materials with high energy densities is a crucial research domain in the modern microelectronics and power systems. The objective of this work was to develop the highly ordered crystal orientations and large ferroelectric crystalline β/γ-phases in the biaxially oriented poly(vinylidene fluoride) (BOPVDF). Importantly, a high discharged energy density and high dielectric constant was achieved by using a high-electric-induced technique. A suitable poling electric field was applied to the BOPVDF films in order to enhance the breakdown strength. Remarkably, the BOPVDF film poled at the electric field of 113 MV m-1 achieved an unprecedented discharged energy density of 25.4 J cm-3 at an ultra-high electric field of 550 MV m-1, which is by far the highest value ever achieved in flexible polymer-based capacitor films. Comparatively, the unpoled BOPVDF and commercial biaxially oriented polypropylene (BOPP) exhibited only a discharged energy density of 7.9 J cm-3 and 1.2 J cm-3, respectively. This systematic study provides a new design paradigm to exploit PVDF-based dielectric polymers for capacitor applications.