【作者】 张海峰；

【导师】 葛新石；

【作者基本信息】 中国科学技术大学 ， 工程热物理， 2006， 博士

【摘要】 用于建筑物空气调节、热水供应、物料干燥的低温热能需求总量巨大。由于时间和强度上的不匹配性，来自太阳能收集、地热能、工业余热等低温热能难以直接满足实际需求。从提高能源利用效率和节能的角度，基于热能贮存的热泵技术是缓解这一矛盾的可行途径。 本文研究低温热能贮存和热泵应用中几个相关的方面，内容涉及热能贮存的方式和贮能系统效率分析、水源热泵的性能和应用研究、贮能材料的热物性测量和预示。 潜热贮能中的传热问题研究 针对相变材料（PCM）物性数据缺乏的现状，研究热针法测量导热系数。通过测量原理的分析对热针法进行优化；改进测试电路提高温度测量的精度。改进后的热针法可以快速简便地测量PCM在固液两态下的导热系数。实验结果表明测试时间不超过20秒，对导热系数为0.1～0.6Wm^-1K^-1的样品测量不确定度为3％。 相变胶囊是微尺度封装的新型PCM。本文运用显热容法求解相变问题，分析相变胶囊在对流边界条件下的蓄放热特性。结果表明微尺度封装具有显著的传热强化效果、相变胶囊在蓄放热过程中热流稳定，小温差条件下仍能保持高效换热。这些优异性能主要源于相变胶囊的尺度特性。 目前潜热贮能的理论研究主要集中在过程分析，很少有关于系统效率的报道。本文通过对管内流体换热式相变贮能系统的研究，综合系统的换热有效度和PCM潜热的利用率，探讨与系统效率相关的因素。尽管系统的尺度特性、流体流动状态和换热温差等条件是系统设计的重要依据，但PCM内部的传热强化才是提高系统效率的关键因素。 水源热泵的性能研究和应用 根据建筑节能这一社会需求，建立太阳能辅助水箱蓄热式热泵供暖的实验系统。实验研究了自行设计的水源热泵（WSHP）机组的性能及其与供热温度的关系。综合实验结果，分析研究了设计中的不足之处和提高性能的措施。作为WSHP的一个应用，实验研究了在夏季机组作为室内空调制冷和热水供应的工作特性。 结合热力学第一和第二定律，分析了WSHP兼作室内空气调节和热水供应的节能效果。通过对比一台空气源热泵热水器和制冷空调机联合运行的功耗，论证了一机两用的热泵系统具有高性价比和显著的节能效果。这一分析也证明了空气源热泵空调系统余热回收的节能意义。更多还原

【Abstract】 The huge quantity of thermal energy is demanded for air-conditioning of buildings, hot water supply and drying processes. The supply of thermal energy can not fulfill such a demand, in terms of the mismatch both in time and intensity. In view of the efficiency of the energy utilization and energy-saving, a potential way is to use the heat pump with thermal energy storage.In this dissertation, several thermophysical problems related to the thermal energy storage and the water source heat pump (WSHP) are investigated. The contents consist of the modes of thermal energy storage and their efficiencies, the performance of WSHP and its applications, and the measurement and prediction of thermal properties of energy storage materials.Heat transfer problems associated with the latent heat storageThe hot probe method is investigated for measurement of the thermal conductivity of the phase change materials (PCMs), for the lack of the data of thermal properties. Two improvements are proposed. The first is to optimize the probe design, based on the theoretical analysis of the measurement principles; the second is to improve the precision of temperature measurement. The improved hot probe can conveniently be used for measuring the thermal conductivity of PCMs, both in liquid and solid states. From the experimental results, the relative measurement uncertainty is about 3%, and the measurement time is less than 20 seconds.Micro-encapsulated PCMs have been receiving much attention recently. Based the apparent heat capacity method for solving the Stefan problem, the heat charge and discharge of the encapsulated PCMs are investigated numerically. The results show that the micro-encapsulated PCMs characterize the desirable behaviors such as the heat transfer enhancement, the stable heat flow and high efficiency of heat exchange under small temperature difference. All these advantages mainly come from its scale characteristic.The process of the latent heat storage has been studied widely. However, few reports are addressed to the efficiency of the latent heat storage system. In this work, the system with internally flowing liquid is investigated. Combined the heat exchange effectiveness and utilization factor of the latent heat, the systematic efficiency is discussed. Although the scale characteristics of the system, the flow state of the fluid and the difference between the heat source and the storage temperatures are important for the system design, it is the key to enhance the heat transfer inside the PCM.Performance of WSHP and its applicationConsidering the demand of the energy-saving of buildings, a solar-aided heat pump system, in which a water tank is used for storage of the collected solar energy for the heat supply in the winter, is set up. The performance of the WSHP is experimentally investigated, with respect to various temperatures of the heat supply. As an additional application, the performance of the WSHP simultaneously served for air-conditioning and hot water supply is also experimentally investigated in the summer.A thermodynamic analysis is given to the WSHP for multi-functional applications. Compared with the energy consumption of two air-source heat pumps, served for refrigeration and更多还原