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Numerical Study of Thermal Performance of Phase Change Material Energy Storage Floor in Solar Water Heating System

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湖南大学学报（自然科学版） 2009年第S1期36卷 141-145页

作者： ZENG Ruo-lang,WANG Xin,ZHANG Yin-ping,DI Hong-fa,ZHANG Qun-li(Department of Building Science,Tsinghua University,Beijing 100084,China) Department of Building Science Tsinghua University Beijing 100084 China

The conventional solar heating floor system contains a big water tank to store energy in the day time for heating at night,which takes much building space and is very heavy.In order to reduce the water tank volume even to cancel the tank,a novel structure of integrated water pipe floor heating system using shape-stabilized phase Change materials(SSPCM)for thermal energy storage was developed.A numerical model was developed to analyze the performance of SSPCM floor heating system under the intermittent heating condition,which was verified by our experimental data.The thermal performance of the heating system and the effects of various factors on it were analyzed numerically.The factors including phase transition temperature,heat of fusion,thermal conductivity of SSPCM and thermal conductivity of the decoration material were analyzed.The results show that tm and kd are the most import influencing factors on the thermal performance of SSPCM floor heating system,since they determine the heat source temperature and thermal resistance between SSPCM plates and indoor air,respectively.Hm should be large to store enough thermal energy in the day time for nighttimes heating.The effects of kp can be ignored in this system.The SSPCM floor heating system has potential of making use of the daytime solar energy for heating at night efficiently in various climates when its structure is properly designed.

关键词： phase Change material energy storage solar water heating

Migration drivers in mountain regions in the context of climate Change:A case study in Shangnan County of China

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Chinese Journal of Population,Resources and Environment 2013年第3期11卷 200-209页

作者： Yinru Lei Max Finlayson Rik Thwaites Guoqing Shi Institution of Land Waterand SocietyCharles Sturt University National Research Center for Resettlement Hohai University

Climate Change has become widely accepted as a challenge that humans will face in the not-too-distant future.Mountain ecosystems and their inhabitants are among the most vulnerable to climate Change.This paper seeks to explain migration drivers in specific mountain regions in the context of climate Change based on Foresight's conceptual framework.A climate Change sensitive field named Shangnan County in southern Shaanxi Province is chosen as the case study area to investigate local migration drivers.A series of qualitative research methods is employed in the case study including participant observation,semi-structured interviews,and focus group discussions.The evidence of survey suggests that migration decisions are not only shaped by macro factors in aspects of environmental,economics,demographic,social,politics and psychological,but also influenced by placed-related barriers and facilitating mechanisms and personal characteristics.

关键词： climate Change migration driver mountain region

Impacts of Regional-Scale Land Use/Land Cover Change on Diurnal Temperature Range

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Advances in Climate Change Research 2013年第3期4卷 166-172页

作者： HUA Wen-Jian CHEN Hai-Shan Key Laboratory of Meteorological Disaster Ministry of Education Nanjing University of Information Science & Technology

The NCAR Community Atmosphere Model(CAM4.0)was used to investigate the climate efects of land use/land cover Change(LUCC).Two simulations,one with potential land cover without significant human intervention and the other with current land use,were conducted.Results show that the impacts of LUCC on diurnal temperature range(DTR)are more significant than on mean surface air temperature.The global average annual DTR Change due to LUCC is–0.1℃,which is three times as large as the mean temperature Change.LUCC influences regional DTR as simulated by the model.In the mid-latitudes,LUCC leads to a decrease in DTR,which is mainly caused by the reduction in daily maximum temperature.However,there are some diferences in the low latitudes.The reduction in DTR in East Asia is mainly the result of the decrease in daily maximum temperature,while in India,the decrease in DTR is due to the increase in daily minimum temperature.In general,the LUCC significantly controls the DTR Change through the Changes in canopy evaporation and transpiration.

关键词： land use/land cover Change diurnal temperature range climate Change

Econometric analysis of the impacts of climate Change on the livestock production in Qinghai Province

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Chinese Journal of Population,Resources and Environment 2013年第4期11卷 299-307页

作者： Yanfei Li Xinsheng Wang Zhihui Li Fang Yin Faculty of Resources and Environmental Science Hubei University Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Center for Chinese Agricultural Policy Chinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences

This study aims to investigate the effect of the impact mechanism of climate Change on the livestock production at small watershed level and county level with the Multi-level Model(MLM)in Qinghai Province.The result indicated that the gross livestock output value was greatly influenced by the climatic factors of the small watershed level.Higher temperature promoted also by the increase of precipitation,relative humidity and sunshine duration was found to be beneficial to the development of livestock production,except in some areas where temperature rise restrained the development of local livestock production to some degree when exceeding a certain level;besides,the impact of the socioeconomic factors on the livestock output value is obvious at the county level.The gross economic output measured with GDP has some inhibitory effects on the reinvestment of livestock production,while population growth promotes development of livestock production to some degree.The results not only provide scientific basis for the management of livestock production in Qinghai Province,but also provide reference for formulating the policies and adaptation measures targeted at climate Change to promote the sustainable development of livestock production in other regions.

关键词： climate Change livestock production Multi-level Model Qinghai Province

Experimental Study on Hybrid Organic Phase Change Materials Used for Solar Energy Storage

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Journal of Thermal Science 2020年第2期29卷 486-491页

作者： WANG Zanshe LI Ran HU Juntao HU Xianwei GU Zhaolin School of Human Settlement and Civil Engineering Xi'an Jiaotong UniversityXiran 710049China

The solar energy utilization in built environment has been limited due to its low heat flux, uneven distribution in time and space and temporal difference in day and night. The phase Change materials have been used to collect the fluctuant solar energy to form a stable energy source for the terminal equipment of the buildings. In this study, the hybrid organic phase Change materials was prepared for the capillary radiant heating system which formed a cascade utilization of solar energy. Firstly, lauric acid and stearic acid were selected as the basic organic phase Change materials and the binary equilibrium phase diagram was completed based on the method of step cooling curve according to the experimental tests data. The results showed that the phase transition temperature of the mixed acid at the lowest eutectic point was 31.2℃ and the latent heat value was 264.3 kJ/kg when the mass mixing ratio was 70% for lauric acid and 30% for stearic acid. Secondly, the expanded graphite was used as an additive to enwrap the mixed acid and enhance the heat conductivity. The experimental results showed that when the mass proportion of expanded graphite in the mixed acid was 10%, the mixed acid could be completely enclosed by expanded graphite and the stability of melting and solidification was optimal. Additionally, the phase transition temperature of the hybrid phase Change material was 31.5℃ and the latent heat value was 217.4 kJ/kg. The novel hybrid phase Change material has a lower eutectic point and a higher latent heat of phase Change, so it has a large application space and is quite suitable for the cascade utilization of solar energy with capillary network heating system.

关键词： lauric acid stearic acid expanded graphite phase Change material solar energy

Temporal-spatial Change and driving mechanism for regional difference of domestic tourism in China

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Chinese Journal of Population,Resources and Environment 2013年第1期11卷 69-78页

作者： Degen Wang Tian Chen Institute of Geographic Sciences and Natural Research CAS The Graduate School of Chinese Academy of Science Tourism Department of Suzhou University

By using the variation coefficient,Gini coefficient and Theil coefficient,this paper makes preliminary exploration of temporalspatial Change features and driving mechanism for regional differences of domestic tourism in China from 1995 to 2009.According to the results,we drew the following conclusions:(1)The regional difference of domestic tourism in China tends to be narrowing generally,and is less than that of inbound tourism,playing an important role in narrowing the overall gap of regional tourism in China.(2)The regional internal difference features:inter-provincial difference in the eastern region and difference among the eastern,central and western regions are comparatively obvious and demonstrate a significantly shrinking tendency,the Change tendency is consistent with the Change tendency of overall difference and exercises a decisive role in overall difference,whereas the inter-provincial difference in the central and western regions is small and relatively stable,having less influence on the overall difference.(3)The temporal-spatial Change in regional difference is featured by:low-level provinces occupy a majority and are concentrated in the central and western regions,showing a tendency of narrowing difference;high-level provinces are concentrated in the eastern region,showing a tendency of spreading to the central and western regions;spatial pattern of regional difference demonstrates 4 types,i.e."proliferation type","polarization type","quiescence type"and"collapse type."(4)The driving force for regional difference of domestic tourism in China comes down to 3 aspects:regional socio-economic attribute,regional transport accessibility level and regional development policy.

关键词： domestic tourism regional difference temporal-spatial Change driving mechanism China

Experimental Investigation of Heat Storage and Heat Transfer Rates during Melting of Nano-Enhanced Phase Change Materials (NePCM) in a Differentially-Heated Rectangular Cavity

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Journal of Thermal Science 2020年第2期29卷 503-511页

作者： LI Zirui HU Nan TU Jing FAN Liwu Institute of Thermal Science and Power Systems School of Energy EngineeringZhejiang UniversityHangzhou 310027China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China

In this work, an experimental study of melting heat transfer of nano-enhanced phase Change materials(NePCM) in a differentially-heated rectangular cavity was performed. Two height-to-width aspect ratios of the cavity, i.e., 0.9 and 1.5, were investigated. The model Ne PCM samples were prepared by dispersing graphene nanoplatelets(GNP) into 1-tetradecanol, having a nominal melting point of 37℃, at loadings up to 3 wt.%. The viscosity was found to have a more than 10-fold increase at the highest loading of GNP. During the melting experiments, the wall superheat at the heating boundary was set to be 10℃ or 30℃. It was shown that with increasing the loading of GNP, both the heat storage and heat transfer rates during melting decelerate to some extent, at all geometrical and thermal configurations. This suggested that the use of NePCM in such cavity may not be able to enhance the heat storage rate due to the dramatic growth in viscosity, which deteriorates significantly natural convective heat transfer during melting to overweigh the enhanced heat conduction by only a decent increase in thermal conductivity. This also suggested that the numerically predicted melting accelerations and heat transfer enhancements, as a result of the increased thermal conductivity, in the literature are likely overestimated because the negative effects due to viscosity growth are underestimated.

关键词： aspect ratio graphene nanoplatelets latent heat storage melting heat transfer phase Change material rectangular cavity

Comprehensive analysis on China's National Climate Change Assessment Reports: Action and emphasis

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Frontiers of Engineering Management 2019年第1期6卷 52-61页

作者： Bing WANG Ge HONG Chao-Qun CUI Hao YU Tad MURTY Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources China University of Mining and Technology (Beijing) Beijing 100083 China College of Resources and Safety Engineering China University of Mining and Technology (Beijing) Beijing 100083 China Center for Energy and Environmental Policy Research Beijing Institute of Technology Beijing 100081 China State Grid Energy Research Institute Company Limited Beijing 102209 China Department of Civil Engineering University of Ottawa Ottawa Canada

Climate Change assessment is central for lowcarbon management practice. This paper investigates China's National Climate Change Assessment Reports of 2007, 2011, and 2015. These three reports are compared with other climate Change assessment reports by data mining. The necessity of national climate Change assessment is analyzed with the requirements at home and abroad. The latest progress surrounding climate Change impacts, adaptation, and mitigation is outlined with the increasing temperature rise in China and the urgency of climate Change commitments. The achievements in climate Change assessment indicate the increasing climate Change vulnerability on sectors and regions in China and the strategies and priorities for low-carbon actions. Distinct gaps and differences are identified in the coverage of industry, regions, and vulnerability assessment between our assessments and other evaluation reports. These gaps and differences demonstrate the importance and future improvements of China's national climate Change assessment in international climate governance. The outlook for China's fourth assessment report is proposed.

关键词： climate Change assessment low-carbon management impact adaptation mitigation

Synthetic optical vortex beams from the analogous trajectory Change of an artificial satellite

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Photonics Research 2019年第9期7卷 1101-1105页

作者： HAIPING WANG LIQIN TANG JINA MA XIUYAN ZHENG DAOHONG SONG YI HU YIGANG LI ZHIGANG CHEN MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Applied Physics Institute and School of PhysicsNankai UniversityTianjin300457China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan030006China Department of Physics and Astronomy San Francisco State UniversitySan FranciscoCalifornia94132USA

We propose a method to generate specially shaped high-order singular beams of pre-designed intensity distributions. Such a method does not a priori assume a phase formula, but rather relies on the 'cake-cutting and assembly' approach to achieve the azimuthal phase gradient for beam shaping, inspired by the orbital motion trajectory Change of an artificial satellite. Based on our method, several typical vortex beams with desired intensity patterns are experimentally generated. As an example, we realize optical trapping and transportation of microorganisms with a triangle-shaped vortex beam, demonstrating the applicability of such unconventional vortex beams in optical trapping and manipulation.

关键词： SOV SLM Synthetic optical vortex beams from the analogous trajectory Change of an artificial satellite