毕业设计-适用于太阳能热水器的太阳能跟踪器文献翻译(17页).doc

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1、-毕业设计-适用于太阳能热水器的太阳能跟踪器文献翻译-第 17 页适用于太阳能热水器的太阳能跟踪器摘要利用太阳能来加热水,已经不是一个新的想法了。数百年前,黑色烤漆水箱就被用来作为一种简单的太阳能热水器在一些国家被尝试。太阳能热水器技术,在过去的一个世纪得到了极大的提升。今天,有超过30万平方米的太阳能集热器安装在全球各地。不计其数的现代太阳能热水器,在诸多国家使用,如中国,印度,德国,日本,澳大利亚和希腊。事实上,在一些国家,法律要求任何新的住宅建筑项目都必须安装太阳能热水器。现在的任务是设计一个新的跟踪装置,使太阳能电池板能够最佳地跟踪一天中太阳光方向的变化。实施这种跟踪,可以大大提高太阳

2、能电池板工作效率,并且使太阳能电池板用来提供给智能家居生活。本文验证了太阳能跟踪器样机的设计和建造过程,这期间积累的经验和遇见的问题也将使我们继续这一项目的研究。1引言 改变太阳能电池板的角度,这样能使太阳能电池板充分利用太阳能。这是通过旋转面板始终垂直于太阳的入射角实现的。初步测试后,这个过程可以提高太阳能发电系统50 的工作效率。这些测试结果说明这是一个很有吸引力的研究,加强了现有的太阳能发电系统。其目标是建立一个跟踪机,完成太阳能跟踪,并实现最高的效率。其终极目标是本项目要符合成本效益,那也就是说随着时间的推移将大大降低发展跟踪机的成本。除了上述功能目标,智能家居还为我们的项目提出了以下

3、的其他目标:必须不依靠外部电源(自我维持) ,必须美观,而且还要能防水。我们设计的太阳能跟踪器包括三个组成部分:框架,传感器和驱动系统。每个都被仔细的审查和检测,实行跟踪。先前的太阳能跟踪小组设计的框架是一个铝棱柱形框架。它采用了一种“格式”设计,并且旋转轴在中间,与方形电池板底部相连的是一个用来支撑集热板的平台。该框架本身有一个角度,此角度的度数由小组对当地实际情况调查而定,其旋转的轨道是系统随太阳从东到西转动,这一过程在白天进行。该传感器系统设计采用了两个小型太阳能电池板作为跟踪机的采集板。这些传感器面板采用垂直的反光镜相连接,除非反光镜接收不到任何太阳光,不然它会遮挡其中一个面板,而另外

4、一个能够接收到太阳光。我们的传感器依靠这种在光线下的差异而工作,结果两种差异很大的面板都能跟踪太阳光的方向驱动电机,直到反光镜子再次得不到任何阳光,而此时双方的太阳能板传感器能得到同等阳光,而且看不到任何差别。 我们认为以往用于跟踪的直接驱动系统是很容易在跟踪时失败的。所以我们设计了一个带系统,该系统的一端是一个具有传动皮带轮和输出的功能的电机。电机旋转带动皮带,然后旋转滑轮上的轮轴。这个系统简单,易于拆解,所以很容易根据需要将传动做进一步的改进和优化。正如任何设计过程中都会遇到问题一样。我们遇到的首要的问题是天气恶劣而影响我们宝贵的测试时间。尽管遇到挫折,我们相信,这样的设计与原型是非常有价

5、值的。在我们的测试中,我们已经消除了许多重复的问题,使今后的工作和该项目的研究更为顺利。我们也已将我们的样机做跟踪太阳的演示,在没有任何外部辅助下,我们能让跟踪器依靠自己的能量旋转和停止,演示过程中没有任何援助。联合国向我们提出的智能家居的主要目标是:在今后的发展中将这项技术推广到普通家庭。所以我们相信我们研究一定能使太阳能跟踪向前迈一大步。2问题设定该项目旨在完成用于智能家居的太阳能跟踪器设计的任务。而团队组成后,由成员完成高级程序设计,客户可以为这个项目进行内部设计。值得一提的是,杰夫泰森代表智能家居与我们进行联系和沟通,以及聪明的众议院领导人也认同我们的研究 。在我们的第一次会议上,杰夫

6、和汤姆确定了以下目标: 1.白天追踪太阳 2.不使用任何外部电源 3.不受天气影响 4.符合成本效益 5.必须外观好看 6.太阳能电池板大众化即能够适用于不同类型的面板根据这些目标,我们构建了质量功能配置图。此图可以发现,其主要关注的方面可能有以下几个:面板数量,面板尺寸 ,内部电源要求,电动机的扭矩要求。 在我们的第一次会议上,我们设定了我们这一阶段的目标:做出一个能够跟踪太阳的工作原型。这也是完成该项目的主要标准,但我们很快发现为了要做到这一点,我们将被迫省略部分的设计,他们希望工作列其后,这将导致在屋顶上的优化平台空间是无效的,我们的目标是有一个平台轨道。它也说明了为了稳定的需要,我们的

7、原型需要测试。我们开始有一个想法,这一想法从头开始,就是有可能使用帧,舍弃最初的设想即采用REV 1设计方案或采用转动原型方案,我们在互联网找到设计图,以应付与杰夫每周一次的会议,以确保我们在设计时能够满足他们的需要。杰夫也将会见汤姆,总之与智能家居的会议每周至少一次,以使每个人都能在同一观点上。从我们的目标开始,我们着手对这一进程进行构想 。3概念和研究3.1跟踪模式我们小组通过集思广益来界定概念。我们的思想理念是为了设计在不同条件下使用的太阳能跟踪装置,以让它们克服不同条件下的困难,再把可行的框架和概念介绍给我们的智能家居。其他概念的产生是通过研究事先存在的太阳能跟踪装置得到的。起初我们的

8、概念是创造一个完全新的太阳能跟踪装置,以前的设计结构方法已经给我们的智能家居提供了思路。这一初步的献策产生了许多观点:第一个观点是一个单向轴跟踪系统,该系统将追踪太阳从东到西横跨天空的全过程,检测每一段时间, 直到第二天结束。这一概念的提出很简单,我们选择使用的结构材料正在制作中;另一种更复杂的概念是双向轴跟踪系统,并在整个季节都能从东到西跟踪太阳。这种概念是较为高效率的利用太阳能;第三个概念是只随季节跟踪。这将提供小型效率收益,但远不及第二个概念提供的从东到西的跟踪装置。我们设计的跟踪装置结构包括一个旋转中心轴和附加板以及液压机或提供主要方向的跟踪的电动升降机,还有一个转到面对着太阳的机械臂

9、。清晰的效率收益,再加上设计简单的单向轴跟踪系统,以及以电机轴为旋转中心轴的结构,使我们能够实现从东到西的跟踪。3.2结构一旦方案被选定下来了,我们有必要决定采用何种手段去支撑这一议案的框架。也就是说由先前的智能家居太阳能跟踪小组提供三角棱柱框架,或通过使用栏目的方式对任何一方提供支持。而提交的棱柱结构较现有的框架的优势在于其简单的几何思路,和能准确的安装在屋顶上能为我们的施工带来方便。由于提高了时间强度的考虑,而我们的预算又有限,再加上现有的框架被证明是最重要的影响因素,由于这些因素,我们决定和过去的太阳能跟踪组合作,让其为我们提供框架。3.3跟踪运动一旦支撑框架被确定下来,我们最后需要一种

10、具体化的措施来决定这项议案。我们决定测试这一议案的可行性,这将推进太阳跟踪器的研究方向和进度的进程。在经过连续讨论议案后,我们决定在原先跟踪太阳的基础上,选择连续跟踪太阳的概念,即预先设定太阳在天空中的位置,再根据其感应的准确性和存在的已知定时技术进行跟踪。在评估阶段我们意识到:连续跟踪太阳能的的议案被证明是困难的。其中一个原因是无法从太阳能板上提取不断的电压和电流,从而需要旋转的方式改变感应器的位置以进行必要的补偿。连续跟踪的议案还需要近乎恒定的功率,在一天的运转中这需要一个机制来存储能量。除了这些因素,安排时间电路和位置传感装置似乎是令人生畏的。与博士乔治协商后,我们决定对跟踪检测装置使用

11、两个面板和测阴影的议案。4分析与体现4.1结构几何构建使电池板高效率的吸收太阳能的几何框架。之所以这样做,是为了让轮换在东西方向的电池板始终对南,这样才能使跟踪器每天和太阳成一个360的倾角(即达勒姆纬度)。因为设计这个框架的初衷是摆在屋顶25的斜坡上,但实际的倾斜度是11。 为了能和奈特博士提出的晴天模式兼容,我们对现有的几何平台的结构做出调整。这种模式导致的结论是:该平台在两个水平方向应当跟踪到达到60。因此,角度范围的框架尚待提高。把双方的帧引入以增加允许的转动角度,而他们带来的比例以维持倾角11。此外,把帧转移到里面的框架以致更大的旋转平台来接触到支持结构。 用于传感和通电旋转的面板放

12、置在平台的平面上。镜子垂直放置着,并和面板之间产生一个差额,以带动功率电机。传感板放在平台外部以确保收集板的最大收集面积。第三块传感面板展开面向东直立,以确保在早晨太阳升起时向着太阳旋转。这个面板被连接到框架下的平台,因此,在一天的大部分时间里,它的阴影与影响是最小的。为了最大限度地减少电机功率的需要,最小力矩是电机的一个主要关注点。该平台设计中用于收集太阳能电池板的转动轴,将与它的旋转轴线对准。由于主面板中大部分的重量使这些旋转轴降低了对轴的扭矩。传感板置于对称轴左右旋转,以避免额外对马达的扭矩。第三块面板连接到的帧代替了该平台或旋转轴,从而也避免了任何扭矩。4.2材料由于它已经构建完毕了,

13、所以在大部分的框架在材料的选择上很简单。用于放大和遮荫传感面板的镜子已经购买并已投入使用。面板新增的附件和后视镜框都是在机加工车间找到的报废零部件。 对于我们选择的传感面板的体积和耗电量都需要加以平衡。该面板将尽可能添加最小应力和重量,而框架还需要得到足够强大的力量旋转平台。因此最强大的中间尺寸面板可供选择。我们在出现的面板中选择了最可靠的。4.3传动机构经过原型设计和测试,电机的购买和使用由先前的太阳能跟踪组完成。与会者建议把它拆除并试图安装一个齿轮系统的简单电机。奈特教授提供了一些皮带和滑轮以及与另一端的轴连接的设备。我们在定这个方案期间分别买了一个充电器和电机,这样使我们有一个6V的电机

14、来给另一个滑轮提供动力了。轴的一端我们通过垫片和皮带将滑轮与另外的滑轮连接起来。但实验表明此电机带动旋转轴强度不足,一旦原电机抽离被送走和检验,这似乎又增加了新的工作:需要购买一个新的滑轮和搭载其的6V电机。5详细设计5.1框架框架的是以一英寸的方形铝管为油管,以及以5英尺长、 2英寸的方管为车轴。它是一个由刚性基片和侧面提供稳定性支撑杆的三角棱柱形框 。轴的一端连接着一个由电机驱动的滑轮系统。这是很容易通过消除双方的错误和折叠结构来传输。5.2传感器我们主要的太阳能面板框架的传感面板底部和支撑下方的半英寸长的L-支架由螺栓连接着。镜子被连接到感测面板的内侧也由L-支架支撑着。整个架构连接简便

15、,主要用4个2英寸的U型螺栓将主面板框连接到主轴。第三个面板是由螺栓固定朝着日出的地平线返回主面板方向的结构。5.3传感器如何工作我们的一个调查小组发现当其中一块面板被遮掩住和放大时,传感器驱动着电机运转,并在其他的很多时候,该系统并非直接面向太阳。两个传感面板装在平行主面板左右对称的中心轴与两面镜子之间。遮荫对其中的面板制造了高阻抗,这种情况直到面板得到同样数额的阳光和平衡 (即当传感面板及主要面板都面向太阳)。当其中一块面板被遮荫时,我们最初试图用一系列配置以充分利用电压差。但这种电压差也不足以驱动电机。其后,我们试图通过平行配置,利用阴影面板的阻抗,并提供所需的电流来驱动电动机。从日出到

16、日落,一旦感应机制有旋转,利用功率电机会将从日出开始到第二天的不同方向的太阳光反馈到第三个面板,而这块面板通常是被遮荫的。6原型测试初步测试工作只用传感元件和1 6 V电机。该小组成员经过一系列的配置后,对传感面板进行最初测试,结果证明是无效的。数据采集显示,最多不超过2V的差异,这是不够准确的。经该面板的整体测试,人们发现这是一个不定值的电压,每个面板肯定各有不同,当21.5V和19.5V时充分放大,并迅速充分填满。目前这些数据分别由对每一块面板测试所得,由于我们认为波动数值为0安培时填满,直至0.65安培时充分放大,因此,为了最大限度的避免太阳能电池板被遮光,我们选择把我们的传感板与电机之

17、间相互平行。测试此方法,当电机在一个方向停下时,传感面板几乎垂直于太阳,如果太阳扭转了方向,同时面板也将旋转保持与太阳光的垂直。为了使电动机停止时误差要非常小,我们调整角度范围。也有人指出,面板旋转接近垂直时,电机不再工作。这个错误可能是由于二个传感面板的结合。测试时,我们发现其中一个面板的电阻是52千欧, ,其他面板的电阻为53 千欧。再通过近一步测试,有感测的太阳能电池板的电机提供的电压和电流,在各点上以保持一致,但不包括当太阳能电池板直接面向太阳时的情况。通过对其中一个面板试验结果表明,电阻可能需要加以补充,以弥补与面板内部电阻的差距,并需要添加以降低电机两端的电压的电压调节器。我们最初

18、对原型的测试发现由于它的滑动造成故障,所以原电机是容易失败的。这导致了该机构的滑轮和皮带驱动系统出现故障,并且会延续故障或打滑。我们的初步测试和原型的成功向我们证明了我们的太阳能跟踪器的设计效果。7结论整个项目中,我们寻求了多方资源的支持。我们之前就明白,必须明确定义问题,是至关重要的,这是提高设计的效率和进展情况所必需的。我们的奋斗让我们得到了和最初设计一样不同于以往太阳能需求者的的跟踪装置,在没有充分权衡利弊大小,决定利用现有的框架,是他们的投资和优势为我们的目的提供了帮助。 我们了解到,在初始阶段的原型设计中,进行部分的设计是关键。几经周折,在测试太阳能电池板时我们才知道,由于天气的不可

19、确定性,我们需要很多的时间去进行太阳能电板是否与太阳光线垂直的相关测试工作。实际执行的使用原型在其预定位置和智能家居屋顶需要的样机一样,以保护线路及电气连接,从放在屋顶的传感,框架,电机,支撑体系,到底部结构,并有可能重新设计以消除过剩的高度和简化整体的几何形状。传感系统可通过提高通过扩大反射镜或通过将眼罩沿着面板的侧面,以减少反射和折射光对传感器的影响的方法加以改进,以得到高效率。Solar Tracker for Solar Water HeaterAbstractUsing the suns energy to heat water is not a new idea. More tha

20、n one hundred years ago,black painted water tanks were used as simple solar water heaters in a number of contries. Solar water heating technology has greatly improved during the past century.Today there are more than 30 million m2 of solar collectors installed around the globe.Hundreds of thousands

21、of modern solar water heatersare in use in countries such as China, India, Germany, Japan, Australia and Greece. In fact, in some countries the law actually requires that solar water heaters be installed with any new residential construction project.The task was to design a prototype tracking device

22、 to align solar panels optimally to the sun as it moves over the course of the day. The implementation of such a system dramatically increases the efficiency of solar panels used to power the Smart House. This report examines the process of designing and constructing the prototype, the experiences a

23、nd problems encountered, and suggestions for continuing the project. 1.IntroductionSolar tracking is the process of varying the angle of solar panels and collectors to take advantage of the full amount of the suns energy. This is done by rotating panels to be perpendicular to the suns angle of incid

24、ence. Initial tests in industry suggest that this process can increase the efficiency of a solar power system by up to 50%. Given those gains, it is an attractive way to enhance an existing solar power system. The goal is to build a rig that will accomplish the solar tracking and realize the maximum

25、 increase in efficiency. The ultimate goal is that the project will be cost effective that is, the gains received by increased efficiency will more than offset the one time cost of developing the rig over time. In addition to the functional goals, the Smart House set forth the other following goals

26、for our project: it must not draw external power (self-sustaining), it must be aesthetically pleasing, and it must be weatherproof.The design of our solar tracker consists of three components: the frame, the sensor, and the drive system. Each was carefully reviewed and tested, instituting changes an

27、d improvements along the design process. The frame for the tracker is an aluminum prismatic frame supplied by the previous solar tracking group. It utilizes an A-frame design with the rotating axle in the middle. Attached to the bottom of this square channel axle is the platform which will house the

28、 main solar collecting panels. The frame itself is at an angle to direct the panels toward the sun (along with the inclination of the roof). Its rotation tracks the sun from east to west during the day. The sensor design for the system uses two small solar panels that lie on the same plane as the co

29、llecting panels. These sensor panels have mirrors vertically attached between them so that, unless the mirror faces do not receive any sun, they are shading one of the panels, while the other is receiving full sunlight. Our sensor relies on this difference in light, which results in a large impedanc

30、e difference across the panels, to drive the motor in the proper direction until again, the mirrors are not seeing any sunlight, at which point both solar panels on the sensor receive equal sunlight and no power difference is seen. After evaluation of the previous direct drive system for the tracker

31、, we designed a belt system that would be easier to maintain in the case of a failure. On one end of the frame is a motor that has the drive pulley attached to its output shaft. The motor rotates the drive belt which then rotates the pulley on the axle. This system is simple and easily disassembled.

32、 It is easy to interchange motors as needed for further testing and also allows for optimization of the final gear ratio for response of the tracker.As with any design process there were several setbacks to our progress. The first and foremost was inclement weather which denied us of valuable testin

33、g time. Despite the setbacks, we believe this design and prototype to be a very valuable proof-of-principle. During our testing we have eliminated many of the repetitive problems with the motor and wiring so that future work on the project will go more smoothly. We also have achieved our goal of tra

34、cking the sun in a hands-off demo. We were able to have the tracker rotate under its own power to the angle of the sun and stop without any assistance. This was the main goal set forth to us by the Smart House so we believe our sensed motion prototype for solar tracking will be the foundation as the

35、y move forward in the future development and implementation of this technology to the house. 2. Defining the ProblemThe project was to complete the “REV 2” design phase of the solar tracker to be used on the Smart House. While the team was comprised of members from the ME160 senior design course, th

36、e customer for this project was to be the Smart House organization. Jeff Schwane, a representative from the Smart House, was our liaison and communicated to our group the direction Smart House leadership wished us to proceed. At our first meeting with Jeff and Tom Rose, the following needs were iden

37、tified: 1. Track the sun during the day2. Use no external power source3. Weather proof4. Cost effective power gain5. Must look good6. Solar panel versatile i.e. can fit different types of panelsWith these needs in hand, we constructed a Quality Function Deployment chart. This chart can be found in A

38、ppendix A. The QFD showed the major areas of concern might have been: number of panels/size of panels, internal power requirements, motor torque required. At our first meeting we were also able to set up our goals for the semester. Having a working prototype capable of tracking the sun was to be the

39、 main goal for the end of the semester, but we soon found that in order to accomplish this, we would be forced to omit portions of the design criteria in hopes they would be worked out later. This would result in the optimization of platform space on the roof to be irrelevant, with our goal being to

40、 have one platform track. It also led to the assumption that our base would not need to be tested for stability or required to be fastened to the roof. With an idea of where we were to begin, from scratch with the possibility of using the frame from the “REV 1” design, and an idea of where we were t

41、o finish, with a moving prototype, we constructed the Gantt chart that can be found in the internet. Our group planned to meet with Jeff once a week to make sure we were on track with the needs of the Smart House. Jeff would also meet with Tom Rose, the director of Smart House, at least once a week

42、in order to keep everyone on the same page. With our goals in mind we embarked on the process of idea generation. 3. Concepts and Research3.1 Tracking TypeOur group used a brainstorming approach to concept generation. We thought of ideas for different solar tracking devices, which proved difficult a

43、t times due to the existing frame and concept presented to us by Smart House. Other concepts were generated through research of pre-existing solar tracking devices. Originally our concept generation was geared towards creating a completely new solar tracker outside of the constraints of the previous

44、 structure given to us by Smart House. This initial brainstorming generated many concepts. The first one was a uni-axial tracking system that would track the sun east to west across the sky during the course of a day and return at the end of the day. This concept presented the advantage of simplicit

45、y and presented us with the option to use materials from the previous structure (which was also intended to be a uni-axial tracker) in construction. Another more complex concept was to track the sun bi-axially which would involve tracking the sun both east to west and throughout the seasons. The adv

46、antage of this concept was a more efficient harvesting of solar energy. The third concept was to only track throughout the seasons. This would provide small efficiency gains but nowhere near the gain provided by tracking east to west. The different structures we came up with to accomplish tracking m

47、otion included a rotating center axle with attached panels, hydraulic or motorized lifts which would move the main panel in the direction of the sun, and a robotic arm which would turn to face the sun. The clear efficiency gains coupled with the simplicity of design of the uni-axial tracking system

48、and the existence of usable parts (i.e. motor and axle) for the rotating center axle structure, led us to the choice of the East to West tracking, rotating center axle concept. 3.2 StructureOnce the method of motion was chosen, it was necessary to generate concepts for the structural support of the axle. Support could be provided by the triangular prismatic structure which was attempted by the previous Smart House solar tracker group or through the use of columns which would support the axis on either side. While the prismatic structure presented the advantage of mobility and an e

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