太阳能跨季节蓄热实验系统设计与实验研究

发布时间：2018-06-04 14:11

本文选题：太阳能 + 蓄热　；参考：《合肥工业大学》2017年硕士论文

【摘要】：能源是现代化建设的基础和动力,能源供应、安全关乎我国现代化建设全局。当前,世界政治、经济格局深刻调整,能源供求关系亦随之发生深刻的变化。我国能源资源约束日益加剧,生态环境问题突出,调整结构、提高能效和保障能源安全的压力进一步加大,能源发展面临一系列新问题、新挑战。太阳能作为一种取之不尽的清洁性能源,其高效利用对于解决能源问题和环境问题有重要的意义。经过将近20年的高速发展,我国已经成为太阳能热利用生产与应用第一大国。但是,当前太阳能蓄热采暖发展仍面临诸多挑战,大规模蓄热采暖示范工程较少、较高的土地使用成本、项目初投资巨大而经济性较差以及跨季节储热技术复杂程度较高等因素严重制约项目的推广。作为蓄热系统的关键组件,水箱和保温材料的性能会严重影响系统的蓄、放热量,其成本亦在整个蓄热系统的投资中占有相当大的比例。蓄热量较小时,圆柱形水箱由于其较低的成本以及良好的保温性能而得到广泛应用,目前国内外学者对圆柱形水箱工作过程的研究已经趋近于成熟。但是当蓄热量较大时,圆柱形水箱的成本剧烈上升,且其寿命和性能均难以达到要求。矩形水箱具有强度高、重量轻等优点,在工程中可以根据场地情况现场拼装焊接,较圆柱形水箱有更高的土地利用率以及更低的成本,在大规模蓄热方面有较为广阔的应用前景。本实验平台采用矩形水箱作为蓄热容器,在实际工况条件下对矩形水箱的保温过程和蓄热过程进行数值模拟和实验分析。课题的主要工作有:1.分析了蓄热技术的应用范围和储热水箱研究现状,论证太阳能蓄热系统的社会效益和环境效益;2.储热方案的确定,并对系统部件进行选型计算;3.建立了矩形水箱的有限元仿真模型,研究了入水口不同流速对水箱蓄热性能的影响以及水箱在保温过程形成温度分层的机理,并在实际工况下进行了实验测试;4.建立了箱体保温材料有限元仿真模型,箱体保温材料厚度和结构对其保温性能的影响;5.通过仿真,研究了管路保温材料厚度对其性能的影响。研究结果表明:1、入口处流速在低于0.1m/s的情况下,水箱在蓄热过程即形成良好的温度分层,水箱上部水温也能够达到较高的水平,水箱有用能数量较多,且品质较好;2、随着入口处流速的升高(大于0.1m/s),水流冲击深度不断加大,水箱内部冷热掺混加强,水箱在蓄热过程中不再形成温度分层,当流速介于0.3m/s~0.4m/s时,水箱内部会形成“低温死角”,当流速大于0.4m/s时,“低温死角”消失,水箱中部会形成“低温水团”,随着入口处水温的上升,水箱出口处流体温度升高,致使太阳能集热器和板式换热器效率下降;3、当前环境条件下,箱体保温材料厚度达到80mm时,外表面温度与环境温差会下降至3℃以内,可以保证较为良好的保温效果;4、箱体保温材料外侧圆弧面与平面为直接过渡,由于形状发生突变,该处热流密度较大,对保温性能影响较大,使用圆角过渡,能够有效降低该处的对流换热强度;5、对于当前系统管路,其外侧保温材料(橡塑保温棉)为厚度30mm时,外表面与环境温差为2.638℃,能够达到良好的保温效果;6、太阳能蓄热实验系统生命周期范围内,每吨蓄热量能够节约标准煤5922.87t,减少二氧化、二氧化硫、烟尘和氮氧化物排放量分别为15.767t、5.92kg、5.92kg和8.59kg,具有良好的社会效益和生态效益。
[Abstract]:Energy is the foundation and motive force of modernization construction. Energy supply and safety are related to the overall situation of China's modernization. At present, the world politics, the economic pattern has been deeply adjusted, and the relationship of energy supply and demand has also undergone profound changes. The constraints of energy resources in our country are becoming more and more serious, the ecological environment is highlighted, the structure is adjusted, energy efficiency and the security of energy security are improved. The energy development is facing a series of new problems and new challenges. As an inexhaustible clean energy source, the efficient utilization of solar energy is of great significance to solve the problem of energy and environment. After nearly 20 years of rapid development, China has become the first country in the production and application of solar heat utilization. At present, the development of solar heating and heating still faces many challenges. The large-scale heat storage and heating demonstration project is less. The high cost of land use, the huge initial investment of the project, the poor economy and the high complexity of the cross season heat storage technology restrict the popularization of the project seriously. The performance of the material will seriously affect the storage and heat release of the system, and its cost also occupies a considerable proportion in the investment of the whole heat storage system. The cylindrical tank is widely used because of its low cost and good thermal insulation performance. But when the heat storage is large, the cost of the cylindrical tank rises sharply, and its life and performance are hard to meet the requirements. The rectangular tank has the advantages of high strength and light weight. In the project, it can be assembled and welded according to the site conditions, and has a higher land use rate and lower cost than the cylindrical tank in the large gauge. The experimental platform uses a rectangular tank as a regenerative container. The heat preservation process and heat storage process of a rectangular tank are simulated and experimentally analyzed under the actual working conditions. The main tasks are as follows: 1. the application scope of the heat storage technology and the research status of the heat storage tank are analyzed. The social and environmental benefits of the solar energy storage system; 2. the determination of the heat storage scheme, and the selection and calculation of the system components; 3. the finite element simulation model of the rectangular water tank is established, and the influence of the different flow velocity on the heat storage capacity of the water tank and the mechanism of the stratification of the temperature of the water tank in the heat preservation process are studied and under the actual working conditions. The experimental test was carried out; 4. the finite element simulation model of box insulation material was set up, the influence of the thickness and structure of the insulation material on the insulation property of the box was established. 5. through the simulation, the influence of the thickness of the heat insulation material on the performance of the box was studied. The results showed that 1, the flow velocity at the entrance was lower than 0.1m/s, and the water tank was formed in the heat storage process. With good temperature stratification, the upper water temperature of the water tank can reach a higher level, the water tank has more useful energy and better quality. 2, with the increase of the flow velocity at the entrance (greater than 0.1m/s), the impact depth of the water flow is increasing, the cold and heat in the water tank is reinforced, and the water tank does not form the temperature stratification during the heat storage process, when the flow velocity is in the 0.3m/s~0.4m. At /s, the "low temperature dead angle" will be formed inside the tank. When the flow rate is greater than 0.4m/s, the "low temperature dead angle" disappears and the middle of the water tank will form a "low temperature water mass". As the water temperature rises at the entrance, the temperature of the outlet of the water tank rises, resulting in the decrease of the efficiency of the solar collector and the plate heat exchanger; 3, under the current environmental conditions, the insulation material of the box body When the thickness reaches 80mm, the outer surface temperature and the ambient temperature difference will fall to less than 3 C, which can ensure better insulation effect. 4, the outer circular arc surface of the insulation material of the box is directly transferred to the plane. Because of the sudden change in the shape, the heat flow density is larger, the heat insulation performance is larger and the corner transition is used, which can effectively reduce the location of the place. Convection heat transfer strength; 5, for the current system pipeline, the external thermal insulation material (rubber and plastic insulation cotton) is 30mm thickness, the external surface and the environment temperature difference is 2.638 degrees, can achieve good thermal insulation effect. 6, solar heat storage experimental system in the life cycle range, each ton of heat storage can save standard coal 5922.87t, reduce two oxidation, sulfur dioxide, smoke, smoke. The emissions of dust and nitrogen oxides are 15.767t, 5.92kg, 5.92kg and 8.59kg respectively, which have good social and ecological benefits.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TK513.5

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