【作者】 何丽娟；

【导师】 陈光明；

【作者基本信息】 浙江大学 ， 制冷及低温工程， 2009， 博士

【摘要】 能源与环境是保证人类社会可持续发展的基础和关键,也是当今世界普遍关注的热点问题,因此太阳能、地热能以及工业废热、废气、废水、余热等低品位能源的利用成为我国缓解能源紧张和保护生态环境的重要战略任务之一。由于低品位能源的热源温度偏低,传统的低品位热驱动制冷空调的制冷效率低,甚至可能导致制冷系统不能正常工作,使得低品位能源在空调制冷行业的应用和发展受到限制。众所周知,冷量也有品位之分,即温度越低的冷量,其品位越高；温度越接近环境温度的冷量,其品位越低。获取高品位的冷量,难度高；而获取低品位的冷量,难度低。本论文从热力学原理出发,比照热变换器原理,提出了一种低品位热驱动的冷变换器制冷系统新流程以期有效解决低品位热驱动空调制冷效率低等问题。对所提出的低品位热驱动冷变换器制冷系统的新流程特性进行了理论研究。在阐述冷变换器制冷系统工作原理的基础上,建立了制冷系统各部件数学模型,利用数值计算方法编写程序进行了数值计算,分析计算了热水温度、冷却水温度、蒸发器冷媒水入口温度等操作参数对循环热力学性能的影响。为了测试操作参数对冷变换器制冷系统性能的影响,本文自行搭建了冷变换器制冷系统性能实验台。在定流量(即热水流量、冷却水流量和冷媒水流量相同)的实验条件下,进行了系统性能的实验研究。实验结果表明,与传统低品位热驱动吸收制冷系统相比,冷变换器制冷系统不仅可以利用低品位热源制取高品位冷量,而且还具有较高的效率,从而扩宽了吸收制冷系统的工作温度范围。最后,在总结冷变换器原理和实验研究结果的基础上,对今后进一步研究工作提出了一些意见与建议。更多还原

【Abstract】 Energy and environment are foundation and keys to the sustainable development of human society. They have become the worldwide concerned problems. The efficient utilization low-grade energy is recognized as one of the most important strategic missions which can relieve the energy sources problems and protect the environments. However, due to the low temperature feature of low-grade thermal energy, efficiency of traditional air conditioning driven by low-grade thermal energy is low and even hardly maintains its normal working condition. These features restricted the application and development of low-grade thermal energy in the refrigeration fields.It is well known that cooling capacity can be graded by its temperature, that is to say, the lower the temperature, the higher the grade of cooling capacity. It is more difficult to obtain higher grade cooling capacity than lower one. Based on the principle of thermodynamics and compared with the heat transformer, a cooling transformer driven by low grade thermal energy was introduced. It can be expected that a cooling transformer driven by low grade thermal energy may work efficiently.Theoretical research on the performance of cooling transformer driven by low grade energy was conducted. Based on the principle of cooling transformer, a simulation model of a new refrigeration system driven by low-grade energy was developed and a mathematical model for each component of the system is presented. The influences of the heating water temperature, cooling water temperature and inlet temperature of the cooled water to the evaporator on cycle performance were evaluated.A cooling transformer driven by low grade energy for experimental investigations was fabricated. The experimental results were obtained under constant flow condition. It indicated that the cooling transformer not only had higher value of refrigeration capacity and higher value of COP, but also the operating temperature range of low-grade energy is broadened, compared with the traditional absorption refrigeration system.Finally, based on the principle of cooling transformer and experimental results, some suggestions on the future researches were proposed.更多还原