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回路型重力热管太阳能蒸汽发生系统的设计及理论分析

Design and Theoretical Analysis on Loop Thermosyphon Solar Steam Generation System

【作者】 彭耀锋

【导师】 孙志坚; 胡亚才; 洪荣华;

【作者基本信息】 浙江大学 , 工程热物理, 2007, 硕士

【摘要】 中高温蒸汽在工业上的用途非常广泛,针对工业上需求量很大的180℃左右的蒸汽,本文设计了回路型重力热管太阳能蒸汽发生系统。该系统独创性地把回路型重力热管与抛物槽聚焦集热器结合起来,利用传热性能优良的回路型重力热管把抛物槽聚焦集热器收集到的太阳能传递给锅筒内的水,产生中高温蒸汽。分析表明回路型重力热管适合与抛物槽集热器结合产生中高温蒸汽,在太阳能热利用的中高温领域有着广阔的前景。本文具体介绍了回路型重力热管太阳能蒸汽发生系统各个部件的设计,对锅筒的设计考虑了其密封、安全阀和压力控制等问题,采用自力式压力调节阀能够使锅筒内蒸汽的压力波动小于±7%,保证了锅筒的稳定安全运行;在完成搭建回路型重力热管太阳能蒸汽发生系统装置的基础上,建立了回路型重力热管系统性能的测量系统,通过分析得到:系统的效率和集热器的效率可以根据测量锅筒的饱和蒸汽温度和压力、回路型重力热管沿程管壁温度、太阳辐射强度以及锅筒排出的蒸汽流量等参数进行计算,并分析确定了上述主要参数的测量方法。通过对回路型重力热管太阳能蒸汽发生系统的传热过程进行热阻分析,建立了系统性能的计算模型,计算结果表明:集热器的热损失系数U,基本不受太阳辐射强度Ⅰ影响,而受吸收涂层的发射率ε的影响比较大,吸收涂层的发射率ε越高集热器的热损失系数U,越大,采用ε=0.1的化学涂铜黑时和ε=0.9的黑板漆作为吸收涂层时,集热器的热损失系数增大了约6.43W/(m~2·K);集热器效率η_c和系统效率η随太阳辐射强度Ⅰ的增大而增大,随发射率增大而减少;集热器效率和系统效率随锅筒内饱和蒸汽温度的升高而减少,当锅筒内饱和蒸汽的温度从170℃升高到200℃时,采用ε=0.9黑板漆、ε=0.4选择性吸收涂料和ε=0.1化学涂铜黑作为吸收涂层时,集热器效率分别减少了1.9%、1.1%和0.3%,系统效率分别减少了3.6%、2.8%和2%。

【Abstract】 Medium-high temperature steam is widely used in industry, in order to produce about 180°C steam which is needed a lot in industry, a loop thermosyphon solar steam generation system is desighed. This system originally combines the loop thermosyphon with the parabolic trough collector. In this system, loop thermosyphon possessed execellent heat transfer property transfer the solar energy which is collected by the parabolic trough collector to the water in heat exchanger to generate medium-high temperature steam. Some analysis indicate that the technology using loop thermosyphon and the parabolic trough collector to produce medium-high temperature steam is very promising.In this paper, the design of every part of loop thermosyphon solar steam generation system is introduced,.The seal、safety valve and pressure control and other problems are considered.A pressure auto control is used to make pressure fluctuate less than±7%; on the base of loop thermosyphon solar steam generation system, system efficiency and collector efficiency can be computed by measuring the temperatures and pressures of steam in heat exchanger, temperatures on some point of loop thermosyphon, and steam flow rate of exchanger. The measure method of these parameters are introduced.Performance compute model is established by analysing heat transfer process and heat resistance of loop thermosyphon system, and the results indicate that: Heatloss coefficient U_L has no business with solar radiate intensity I, but is quite influenced by emissivityεof absorb coat. Heat loss coefficient U_L increases asemissivityεincreases; Heat loss coefficient U_L increase by 6.43 W/(m~2·K) when using chemical copper black(ε= 0.1 ) compares with using blackbloard lacquer(ε= 0.9); Collector efficiencyη_c and system efficiencyηboth increase with solar radiate intensity I increases, and decreased with emissivityεof absorb coat increases; When using blackboard lacquer(ε= 0.9 ),selectively absorb dope(ε= 0.4 )and chemical copper black(ε= 0.1) as absorb coat, the collectorefficiencyη_c and system efficiencyηboth decrease with the increase of steam temperature in heat exchanger, and collector efficiencyη_c respectively decreases by1.9%, 1.1% and 0.3%, meanwhile system efficiencyηrespectively decreases by 3.6%, 2.8% and 2% as steam temperature increases from 170°C to 200°C.

  • 【网络出版投稿人】 浙江大学
  • 【网络出版年期】2008年 06期
  • 【分类号】TK513
  • 【被引频次】8
  • 【下载频次】455
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