平板集热的太阳能海水淡化系统性能研究

发布时间：2018-05-24 10:11

本文选题：太阳能 + 平板集热器　；参考：《大连理工大学》2014年硕士论文

【摘要】：21世纪是水的世纪,世界上越来越多的国家开始关注淡水资源短缺的问题。目前传统的海水淡化技术已经取得了一定的发展,但消耗大量的化石燃料,带来温室效应、雾霾等环境问题。太阳能海水淡化技术是一种可持续发展的方法。本文以平板集热的太阳能低温多效蒸发海水淡化系统为研究对象。平板集热器具有采光面积大,易于建筑一体化等优势,符合未来太阳能利用的发展趋势,低温多效蒸发技术对热源要求不高,能够较好的耦合太阳能平板集热系统。在质量守恒和能量守恒的基础上,建立了太阳能低温多效蒸发海水淡化系统的数学模型和成本计算模型,利用MATLAB语言对系统进行编程并求解。本文分析了不同月代表日集热器集热量和效率的变化情况,将淡水成本最低时的集热器负荷作为集热器的设计负荷。在此基础上,分析平板集热器面积、集热器出口水温、多效蒸发系统效数和首效加热蒸汽温度对系统性能的影响。在本文计算条件下,集热器面积增大,除人员成本不变,系统的其它各个成本均有一定的升高,系统的淡水产量变大,单位集热面积淡水产量变小,淡水成本逐渐减小；集热器出口水温增大,储热水箱成本缓慢减小,系统其它各成本基本保持不变,淡水产量和单位集热面积淡水产量基本保持不变,淡水成本缓慢降低；多效蒸发系统效数增大,蒸发器成本和土建安装费用均增加,系统其它各成本基本保持不变,淡水产量和单位集热面积产水量增大,淡水成本逐渐降低；首效加热蒸汽温度增大,储热水箱成本升高,电辅系统运行成本先增加后基本保持不变,蒸发器成本逐渐减低,系统其它各成本基本保持不变,淡水产量和单位集热面积产水量先增加后减小,淡水成本先减小后增大。对去除电辅系统的固定装置,针对变负荷情况进行了性能分析,装置负荷率在40%～110%之间变化,系统变负荷时的淡水成本低于没有去除电辅的额定负荷系统的淡水成本。最后,对比分析了真空管和平板集热的太阳能海水淡化系统的热经济性能。在本文计算条件下,针对相同的集热面积,平板集热器的集热量大于真空管集热器的集热量,且平板集热的海水淡化系统淡水产量大,淡水成本小。但由于平板集热器集热量波动比较大,导致其电辅系统运行成本高,从能量利用角度,不够节能。
[Abstract]:The 21st century is the century of water. More and more countries in the world begin to pay attention to the shortage of freshwater resources. At present, the traditional desalination technology has made a certain development, but it consumes a lot of fossil fuels, which brings about environmental problems such as Greenhouse Effect, haze and so on. Solar desalination is a method of sustainable development. In this paper, the solar energy low-temperature multi-effect evaporation desalination system is studied. The flat plate collector has the advantages of large lighting area, easy integration of building and so on. It is in line with the development trend of solar energy utilization in the future. The low temperature multi-effect evaporation technology does not require high heat source, and it can better coupling solar flat panel heat collection system. On the basis of mass conservation and energy conservation, the mathematical model and cost calculation model of solar water desalination system with low temperature and multi-effect evaporation are established. The system is programmed and solved by MATLAB language. In this paper, the variation of heat collection and efficiency of different month representative daily collector is analyzed. The collector load when fresh water cost is the lowest is taken as the design load of collector. On this basis, the effects of the area of flat plate collector, the outlet water temperature of collector, the validity of multi-effect evaporation system and the first effect heating steam temperature on the performance of the system are analyzed. Under the conditions of this paper, the collector area increases, except for the personnel cost, the other costs of the system are all increased, the fresh water output of the system becomes larger, the fresh water production per unit heat collection area becomes smaller, and the fresh water cost decreases gradually. The water temperature at the outlet of the collector increases, the cost of the hot water storage tank decreases slowly, the other costs of the system basically remain unchanged, the fresh water production and the fresh water production per unit heat collecting area remain basically unchanged, the fresh water cost decreases slowly, and the efficiency of the multi-effect evaporation system increases. The evaporator cost and civil installation cost are increased, the other costs of the system remain basically unchanged, the fresh water output and water production per unit heat gathering area increase, the fresh water cost decreases gradually, the first effect heating steam temperature increases, the storage and hot water tank cost increases, The operating cost of the electric auxiliary system first increases and then remains unchanged, the evaporator cost decreases gradually, the other costs of the system basically remain unchanged, the fresh water output and water production per unit heat gathering area increase first and then decrease, and the fresh water cost decreases first and then increases. The performance analysis of the fixed device for removing the electric auxiliary system is carried out. The load rate of the device varies between 40% and 110%, and the fresh water cost of the system with variable load is lower than that of the rated load system without the removal of the power auxiliary. Finally, the thermal and economic performance of solar desalination system with vacuum tube and plate collector is compared and analyzed. In this paper, for the same heat collecting area, the heat collection of flat plate collector is larger than that of vacuum tube collector, and the fresh water production of seawater desalination system with flat plate collector is large and the freshwater cost is small. However, due to the large heat collection fluctuation of the plate collector, the operation cost of the electric auxiliary system is high, so it is not enough to save energy from the point of view of energy utilization.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P747;TK513.1

【参考文献】