The heat transfer performance of the phase change materials used in free cooling and air conditioning applications is low,due to the poor thermal conductivity of the materials.The recent phenomenal advancement in nano...The heat transfer performance of the phase change materials used in free cooling and air conditioning applications is low,due to the poor thermal conductivity of the materials.The recent phenomenal advancement in nano technology provides an opportunity for an appreciable enhancement in the thermal conductivity of the phase change materials.In order to explore the possibilities of using nano technology for various applications,a detailed parametric study is carried out,to analyse the heat transfer enhancement potential with the thermal conductivity of the conventional phase change materials and nano enhanced phase change materials under various flow conditions of the heat transfer fluid.Initially,the theoretical equation,used to determine the time for outward cylindrical solidification of the phase change material,is validated with the experimental results.It is inferred from the parametric studies,that for paraffinic phase change materials with air as the heat transfer fluid,the first step should be to increase the heat transfer coefficient to the maximum extent,before making any attempt to increase the thermal conductivity of the phase change materials,with the addition of nano particles.When water is used as the phase change material,the addition of nano particles is recommended to achieve better heat transfer,when a liquid is used as the heat transfer fluid.展开更多
建筑光伏一体化小区中富余能源并网将导致居民用电经济性欠优,以及与外电网交换功率不够平滑的问题。为此,该文提出一种面向含相变储能系统(phase change material thermal energy storage system,PCMTESS)的小区建筑电-热联供系统双层...建筑光伏一体化小区中富余能源并网将导致居民用电经济性欠优,以及与外电网交换功率不够平滑的问题。为此,该文提出一种面向含相变储能系统(phase change material thermal energy storage system,PCMTESS)的小区建筑电-热联供系统双层调度策略。简要介绍PCMTESS的物理构造和运行模式,并分析其规模化储能和热电解耦的特性。在此基础上,评估阳光辐射等环境因素对光伏发电和建筑热需求的影响,建立计及热泄漏过程的电热联供系统模型。进而,以微网最小化购电成本和对外功率波动为目标,设计一种实时滚动的双层优化调度策略,用于消解预测误差在多时间尺度上的影响。最后,提出近似线性化处理和电力侧-热力侧问题交互迭代的算法,实现优化模型的高效求解。仿真结果表明,该文所提的PCMTESS在维持室温舒适的前提下,既能保障用户侧运行经济性的需求,又能平滑对外交换功率,使得电网与用户双方共同受益。该文为微网综合能源消纳问题的解决提供一个新视角。展开更多
文摘The heat transfer performance of the phase change materials used in free cooling and air conditioning applications is low,due to the poor thermal conductivity of the materials.The recent phenomenal advancement in nano technology provides an opportunity for an appreciable enhancement in the thermal conductivity of the phase change materials.In order to explore the possibilities of using nano technology for various applications,a detailed parametric study is carried out,to analyse the heat transfer enhancement potential with the thermal conductivity of the conventional phase change materials and nano enhanced phase change materials under various flow conditions of the heat transfer fluid.Initially,the theoretical equation,used to determine the time for outward cylindrical solidification of the phase change material,is validated with the experimental results.It is inferred from the parametric studies,that for paraffinic phase change materials with air as the heat transfer fluid,the first step should be to increase the heat transfer coefficient to the maximum extent,before making any attempt to increase the thermal conductivity of the phase change materials,with the addition of nano particles.When water is used as the phase change material,the addition of nano particles is recommended to achieve better heat transfer,when a liquid is used as the heat transfer fluid.
文摘建筑光伏一体化小区中富余能源并网将导致居民用电经济性欠优,以及与外电网交换功率不够平滑的问题。为此,该文提出一种面向含相变储能系统(phase change material thermal energy storage system,PCMTESS)的小区建筑电-热联供系统双层调度策略。简要介绍PCMTESS的物理构造和运行模式,并分析其规模化储能和热电解耦的特性。在此基础上,评估阳光辐射等环境因素对光伏发电和建筑热需求的影响,建立计及热泄漏过程的电热联供系统模型。进而,以微网最小化购电成本和对外功率波动为目标,设计一种实时滚动的双层优化调度策略,用于消解预测误差在多时间尺度上的影响。最后,提出近似线性化处理和电力侧-热力侧问题交互迭代的算法,实现优化模型的高效求解。仿真结果表明,该文所提的PCMTESS在维持室温舒适的前提下,既能保障用户侧运行经济性的需求,又能平滑对外交换功率,使得电网与用户双方共同受益。该文为微网综合能源消纳问题的解决提供一个新视角。
