Repositorio Institucional de Documentos

Postadress: Besöksadress: Telefon: Box 1026 Gjuterigatan 5 036-10 10 00 (vx) 551 11 Jönköping Design and development of the outer housing of a small wind turbine for Windforce © Design och utveckling av det yttre huset av en liten vindturbin för Windforce © César Alonso Martínez BACHERLOR THESIS 2014 Field of Industrial Design and Product Development Exchange student (Erasmus Program) Postadress: Besöksadress: Telefon: Box 1026 Gjuterigatan 5 036-10 10 00 (vx) 551 11 Jönköping Design and development of the outer housing and vane of a small wind turbine for the company Windforce CÉSAR ALONSO MARTÍNEZ This bachelor thesis has been performed at the School of Engineering in Jönköping University (Sweden) during the spring semester in 2014. The project has been developed during an exchange program and will be validated as the Final Project Work for the Degree in Industrial Design and Product Development in the University of Zaragoza (Spain). Tutor: Magnus Andersson Extent: 15 points Date: 15/07/2014 Filing number: Abstract ii Abstract iii Abstract The aim of this project was to design and develop an outer cover/housing for an already existing product. This product is called Wind Flower and is a new small wind turbine released by the Swedish company Windforce, which manufactures wind power solutions and solar systems. After the research stage, the project will be handled focusing on the user needs and applying industrial design methodologies that will include a design brief, a work breakdown structure, functional analysis, sketches, models and more. The final result presented in this report is one of the many solutions that exist to the design problem, but still focused on the user and respecting the design principle “design follows function”. iv Summary This report starts with an introductory phase that talks about the background of the project and the company itself. Later the main objectives and limitations of the work will be explained to make the reader understand the purpose of the project. A theoretical background regarding the industrial design issue and the wind energy topic will precede a chapter that will include design methodologies. These methods will be implemented in a later phase and all the knowledge gathered will be demonstrated as well. In the last chapters the final result will be shown though visualizations and pictures, and conclusions will be stated in order to summarize the main findings of the project. The last two chapters will show the references and the attachments. v Acknowledgements I would like to thank the following people that have helped to make this project happen and have shown their support or shared their knowledge as a guide. Magnus Andersson Project supervisor, Jönköping University (Jönköping, Sweden) Ulf Bolumlid Windforce’s CEO and energy advisor Thomas Arnell Lecturer in Industrial Design, Jönköping University (Jönköping, Sweden) Lars Ericsson Professor in Industrial Design, Program coordinator of the master program in Industrial Design, Jönköping University (Jönköping, Sweden) Nils-Eric Andersson Bachelor Thesis coordinator, Jönköping University (Jönköping, Sweden) Keywords: wind power, small wind turbine, Windforce, housing, cover, vane, industrial design, design thinking, fiberglass, glass-fiber, micro-wind, mini-wind, milling machine. vi Table of Contents Abstract .......................................................................................................................................... iii Summary ........................................................................................................................................ iv Acknowledgements ........................................................................................................................ v Table of Contents ......................................................................................................................... vi 1 Introduction ........................................................................................................................... 6 1.1 Background ..................................................................................................................... 6 1.1.1 Windforce ................................................................................................................ 6 1.1.2 The Wind Flower .................................................................................................... 7 1.1.3 The design competition.......................................................................................... 9 1.2 Objectives ...................................................................................................................... 10 1.3 Delimitations ................................................................................................................. 10 1.4 Disposition .................................................................................................................... 11 2 Theoretical Background ..................................................................................................... 12 2.1 Design ............................................................................................................................ 12 2.1.1 Design Thinking .................................................................................................... 12 2.1.2 Industrial Design and Product Development ................................................... 12 2.1.3 The Design Process .............................................................................................. 13 2.2 Wind energy .................................................................................................................. 15 2.2.1 Wind power ........................................................................................................... 15 2.2.2 Small wind turbines .............................................................................................. 15 2.2.3 Micro-wind and mini-wind .................................................................................. 17 3 Method ................................................................................................................................. 19 3.1 The design brief ............................................................................................................ 19 3.2 Work Breakdown Structure (WBS) ............................................................................ 19 3.3 Project planning ............................................................................................................ 19 3.4 Market analysis .............................................................................................................. 20 3.4.1 Competitor analysis .............................................................................................. 20 3.4.2 Stakeholder analysis .............................................................................................. 20 3.4.3 Target group .......................................................................................................... 21 3.5 Functional analysis ........................................................................................................ 21 3.6 Empirical investigation ................................................................................................ 22 3.7 Ideation and sketching ................................................................................................. 22 vii 3.8 Syntactic, Semantic and Pragmatic ............................................................................. 22 3.9 Computer-aided design (CAD) modeling ................................................................. 22 3.10 Physical modeling ..................................................................................................... 23 4 Approach and Implementation ......................................................................................... 23 4.1 Define the problem ...................................................................................................... 24 4.1.1 Design brief ........................................................................................................... 24 4.1.2 Work Breakdown Structure ................................................................................. 25 4.1.3 Project Planning .................................................................................................... 25 4.2 Collect information ...................................................................................................... 26 4.2.1 Investigation of the company .............................................................................. 26 4.2.2 Market analysis ...................................................................................................... 30 4.2.3 Material research: Fiberglass ................................................................................ 32 4.2.4 Functional Analysis (FA) ..................................................................................... 33 4.2.5 Aerodynamics ........................................................................................................ 34 4.3 Generate ideas and analysis ......................................................................................... 36 4.3.1 Ideation and sketching ......................................................................................... 36 4.3.2 Syntactic, Semantic and Pragmatic ..................................................................... 39 4.4 Develop solutions and refinement ............................................................................. 42 4.4.1 Concept ideas ........................................................................................................ 42 4.4.2 CAD modeling ...................................................................................................... 45 4.4.3 Physical modeling ................................................................................................. 49 5 Result .................................................................................................................................... 50 6 Conclusion and discussion ................................................................................................ 60 7 References ............................................................................................................................ 61 8 Attachments ......................................................................................................................... 64 Introduction 6 1 Introduction 1.1 Background In this first stage the background of the project will be described, and important information about the company and the product in question will be discussed. 1.1.1 Windforce Windforce is a Swedish company that develops and produces small wind turbines, solar panels and other smart systems. They are aware of the huge amount of clean and natural energy existing around and they seize it. But this is not the only cause that drives the company; they comprehend the importance of caring for the planet and fight for a cleaner world with environmental-friendly solutions, deploying engineering processes to achieve this. The company offers not only individual products but also complete hybrid systems that combine wind and solar energy-based solutions at affordable prices. Windforce also markets other devices in the energy technology field, and can provide alternate options to its customers tailored to their needs. Image 1. House with hybrid system installation (source: see References) Among their wind power solutions, they provide several small-scale wind turbines varying in size, power output and in lesser capacity, appearance. Theoretical Background 13 through the generation of ideas, the evolution of these, its technical definition for production, the definition of a strategy of communication for the market and the tasks of coordination and management needed for the success of the rest (University of Zaragoza, 2010). 2.1.3 The Design Process The process of a normal design task can follow different steps. First of all it is necessary to state the problem and the objectives. After doing some research and collecting information from different sources and analyzing it, ideas are generated and valued. The next step is to develop solutions at the same time that these are analyzed, creating a feedback in a circular process based on the pattern Action > Results > Reflection > Plan. See Figure 1. Cyclic approach of Action Research. When the best solution is achieved, it is improved and refined until the final design comes. Figure 1. Cyclic approach of Action Research (Williamson, 2002) Action ResultsReflection Plan Theoretical Background 14 Figure 2. The design process (Chicago Architecture Foundation) (NASA, 2008) Bruno Munari (1979) proposed a design process for general applications and for projects that do not require high technical requirements, like formal object designs, user-oriented products, et cetera. It that can be represented as follows: Figure 3. Design process flow by Bruno Munari (University of Zaragoza, 2010). PROBLEM Problem definition •Problem elements •Data compilation •Data analysis Idea •Creativity •Materials and technology •Experimentation Models Verification Construction drawings SOLUTION Theoretical Background 15 2.2 Wind energy This part will focus on theoretical knowledge about the wind energy and the different ways of taking advantage of the power that it provides. 2.2.1 Wind power Wind power comes when wind energy is transformed into a useful form of energy. One example of this transformation today can be seen in wind turbines, which seize the wind flow rotating their blades and convert it into electrical power. But humans have been harnessing the energy of the wind for thousands of years, for instance around 200 B.C. using windmills to grind cereal grains in Persia (converting wind power into mechanical power), or wind pumps in China (converting wind power into water pumping). Or even earlier, around 5000 B.C., using sails to propel boats along the Nile River (Wind Energy Foundation, 2014). The use of this kind of energy keeps growing nowadays and it is expected to progress in such a fashion. Its rising popularity is due to several facts: it is renewable, so it means a good alternative to fossil fuels; it is plentiful and widely distributed, so this means that wind power would not be restricted for only part of the population; it is clean and produces no greenhouse gas emissions during operation; it does not require much land to be installed (Fthenakis & Kim, 2009); and finally, its effects on the environment are not as serious as those from other power sources (REN21, 2011, p. 11). 2.2.2 Small wind turbines Wind turbines are devices based on electrical generators that convert kinetic energy from the wind into electrical power. Although large wind turbines are the most common way to seize the wind power by means of wind farms that produce hundreds of Megawatts every year, this project will focus on small wind turbines, due to the fact that the Wind Flower is one of them. There are two main types of wind turbines, the ones with vertical axis (VAWT, standing for Vertical Axis Wind Turbine) and the ones with horizontal axis (HAWT, Horizontal Axis Wind Turbine). 2.2.2.1 HAWT In this kind of wind turbine, the rotational axis is parallel to the ground. This is the most common technology given its efficiency and reliability. The small wind turbines based on this disposition are normally composed by a generator, the blades which number can vary from two to several pairs, a central piece to hold the blades and a mast that holds everything on top. Their design needs a vane to place them in the right direction of the wind. Its disadvantages are that they do not work very well with a quick direction-changing wind, Theoretical Background 16 their low efficacy with turbulences and the rotor‟s noise. Normally they stand on a mast and are not recommended to be placed on a roof because of the turbulences that the wind makes when hitting it. 2.2.2.2 VAWT The axis in this type is perpendicular to the ground and they have lower rotational speed than the HAWT. They do not require a vane and can be placed closer ones from other if put in arrays, since they have omnidirectional blades instead of rotational ones. VAWT turbines can be placed closer to the ground due to their capacity to work with a lower wind speed than the HAWT, so the maintenance is simpler. They are also generally more silent than the HAWT and more recommended for low-power installations, but more expensive in materials, less efficient and less reliable when talking about stability or durability. Image 6. The three sub-types of wind turbines (sources for images: see References, 7). Table 1. Advatages and disadvantages of HAWTs, Lift VAWTs and Drag VAWTs (Randall, Timmers, & Skies, 2003;2001;2003) Theoretical Background 17 As the the World Wind Energy Association (2013) states, the early HAWT technology has dominated the market for over 30 years. Based on the study of 327 small wind manufacturers as of the end of 2011, 74% of the commercialized one-piece small wind manufacturers invested in the horizontal axis orientation while only 18 % have adopted the vertical design. 6% of the manufactures have attempted to develop both technologies. Figure 4. SWT (Small Wind Turbines) orientation by manufacturers by 2011 (World Wind Energy Association, 2013). 2.2.3 Micro-wind and mini-wind The small-scale generation to produce electric power by individuals is called microgeneration. When talking about micro-wind turbines, they can vary from 50 W to a few kW. Although the use of these turbines may be motivated by a bad grid power or lack of electrical power, their use is growing as an environmentally conscious approach. Miniwind refers to the use of more than one small wind turbine and it is defined by a top power value of 100 kW. Apart from contributing to the domestic power supply, users of micro-wind and mini-wind devices can also sell the unused power back to the electrical supplier. In the end of 2011, the mini-wind world production reached 576 MW and it keeps growing every year. In addition, there already exist more than 330 small wind turbines manufacturers in more than 40 countries worldwide, with China and the United States of America being the main markets (World Wind Energy Association, 2013). Theoretical Background 18 Figure 5. Total Cumulative Installed Small Wind Units Worldwide (World Wind Energy Association, 2013). Figure 6. Small Wind Manufacturers Map Distribution Worldwide As of the End of 2011 (World Wind Energy Association, 2013). Approach and Implementation 19 3 Method In this section the methods used will be described from a theoretical perspective, and applied later in chapter four. 3.1 The design brief The design brief is a vital part to any design project as it will provide the designer with all the information needed to exceed the client‟s expectations. A design brief should primarily focus on the results and outcomes of the design and the business objectives of the design project. It should not attempt to deal with the aesthetics of design or its possible solutions and if it is done in the right way it will ensure that the clients get a high quality design that meets their needs (Cass, 2008). 3.2 Work Breakdown Structure (WBS) As B.A. Hamilton notes in his Earned Value Management Tutorial (1998), the Work Breakdown Structure (WBS) is a tool that defines a project and groups the project‟s discrete work elements in a way that helps organize and define the total work scope of the project. Each descending level of the WBS represents an increased level of detailed definition of the project work. Additionally it is a dynamic tool and can be revised and updated as needed by the project manager. Figure 7. WBS waterfall diagram example (Institute for Geoinformatics, Münster, 2007) 3.3 Project planning In order to follow an organized and logical flow of work that ensures the success of the project, a project planning is needed. One good project management tool is the Gantt chart. It helps to plan and coordinate all the tasks that have to be done within concrete margins of time. It consists of a vertical axis representing the tasks to be done in the project and a horizontal axis representing the time spent in each task. Approach and Implementation 20 Gantt charts give a clear illustration of the project status, but they have one problem; that they do not indicate task dependencies. This means that it is not possible to tell how one task falling behind schedule affects other tasks (Rouse, 2007). Figure 8. Gantt Chart example (DlhSoft Gantt Chart Library). 3.4 Market analysis The market analysis is the section in a project plan where information about the commercial market in which the business is based is presented. It also remarks the purchasing habits of customers in that market and information about competitors. 3.4.1 Competitor analysis A competitive analysis is a critical part of any market analysis plan. With this evaluation, it can be established what makes the company‟s product or service of unique, and therefore what attributes it highlights in order to attract its target group (Entrepreneur). For this project, it will include an overview of the general competitors‟ products and specifications as well as a deeper analysis of one concrete competitor from different points of view (product range, market relevance, energetic efficiency, customer care, company‟s website, et cetera). 3.4.2 Stakeholder analysis According to Dr. L. Bourne (2011), “building and managing relationships with senior stakeholders is essential for success.” Approach and Implementation 21 The company‟s stakeholders will be all the people, groups or organizations that are influenced by any step of the product‟s lifecycle. The stakeholder analysis in this project will summarize the main groups affected by any action of Windforce regarding the Wind Flower from its conception and design, through its production and distribution, use and finally waste (Certo, 2005). 3.4.3 Target group A target group is a group of customers towards whom a business company has decided to aim its marketing efforts and ultimately its merchandise (Kurtz, 2010). It is defined by common needs, benefits, lifestyle, demographics, etc., and will define the main steps that the company will follow to design, develop and distribute a product. Image 7. Target group visualization (source: printwand.com) The objective of many companies regarding their communication approaches is to create an affinity or loyalty between them and the customer, so it will mean a retribution for them in the future. 3.5 Functional analysis Understanding product functions is a key aspect of the work undertaken by engineers involved in complex system design (Aurisicchio, Bracewell, & Armstrong, 2013). Although this project is more about a formal-based work, one industrial design principle inspired by Louis Sullivan (1896) quotes that “form ever follows function”. And it is a fact that form and function cannot be separated when performing a design: they are strongly related and complement each other. Therefore, during the preliminary stage of this project, a functional design diagram will be implemented in order to gain knowledge about the function and relevance of every component and sub-component of the Wind Flower. Approach and Implementation 22 3.6 Empirical investigation Empirical research is the way of gaining knowledge through experimentation or observation rather than forming knowledge from theories or beliefs. Some examples that can be implemented in this project would be interviews, simple observation (evidence), experiments and tests. 3.7 Ideation and sketching Ideation is the creative process of generating, developing, and communicating new ideas, where an idea is understood as a basic element of thought that can be visual, concrete, or abstract. It is an essential part of the design process, both in education and practice (Jonson, 2005, p. 613) (Broadbent, 2004, p. 54). Creative ways of displaying this ideation can be sketching or brainstorming. 3.8 Syntactic, Semantic and Pragmatic Design is widely identified with the shape of products, but a wider focus is required if “interdisciplinary design” wants to be addressed. Traditional interdisciplinary design deals mainly with the syntactical composition of parts within a whole (Schwarzfischer, 2011, Vol. 33, s. 345). This means that it has to do with the shape of objects and its size, weight, scale, proportions, colors, textures, anthropometry, etc. (University of Zaragoza, 2010). However, this is not enough to identify a design due to the fact that persons vary in time and situational roles, so it is necessary to consider different ideals simultaneously (Schwarzfischer, s. 345). Semantics provide the main meaning to a design, and therefore also the product recognition, function and use identification, brand perception or sociocultural values. Finally, the pragmatic part gives a description about the main objective function, the benefits of the product or its complementary features (secondary functions). Also treats with the components layout, the productive processes, use sequence or biomechanics (University of Zaragoza). 3.9 Computer-aided design (CAD) modeling Computer-aided design (CAD) helps designers to create elaborate three-dimensional virtual objects (3D models) with the help of CAD software. It helps to visualize in a clearer way the shape of a piece or product and also supports verifying its dimensions, proportions, assemblies, etc. Volume or weight calculations can be also made from CAD designs, as well as static or dynamic mechanical simulations. Approach and Implementation 29  I do not have an advanced aerodynamic physics knowledge, does it cause any problem for the design of the vane or outer cover? No, just be between some margins of measures and will be OK.  What about manufacturing processes? Many parts from suppliers and some of their blades produced by them in a workshop.  Which is your background as a designer? Involved in car design but many years ago.  Should the company logo be included in the final product? Yes, in the vane.  Do you have any technical drawings of the Wind Flower? No.  Is the famous quote “form follows function” one of your principles? Yes, absolutely. Image 12. Ulf Bolumlid tracing the bracket's outline. 4.2.1.3 Results I was surprised by some facts but the one that most impressed me was that they did not have any technical drawing of the Wind Flower, considering that they already had 12 in production. So, when I asked how I was supposed to start with the design, Ulf took a large roll of heavy paper and one single bracket and traced its silhouette and the one of a provisional vane on it. He also gave me 3 blades to help me with the proportions. So then I left Ulf‟s house and workplace carrying a 1:1 drawing, some notes and 3 blades of the Wind Flower. Approach and Implementation 30 4.2.2 Market analysis I studied the wind power market in general and the small wind turbines market in particular and after collecting a lot of theoretical information (see chapter 2.2), I looked for the competitor‟s offer, at the main stakeholders implicated and also tried to define a target group. 4.2.2.1 Competitor analysis I extracted some information about small wind turbine manufacturers from the Small Wind World Report Update Summary (2013) which provides worldwide statistics of the small wind market, trend analysis, country/region reports, reports on policies, standards, certification & testing and also market forecasts within the industry of small wind turbines. The main competitors coming from abroad are from China and the United States, the two countries with the most Cumulative Installed Capacity (225‟000 and 198‟000 kW respectively) (World Wind Energy Association, 2013). The description of some of the competitors and their product type offer, size in kW and countries of presence can be found in the Attachment 3. The conclusion after looking at all the competitors found is that all of them offer similar products (either VAHT wind turbines or HAHT ones), with more/less power output or bigger/smaller sizes and number of blades. But I could not find any company that offered a product as differentiated as the Wind Flower. And the truth is that this Winforce‟s peculiar turbine has a working principle that no other turbine uses in the small-scaled wind turbine market nowadays. I consider this to be a critical, competitive advantage that will result in good results and income for the company, if Windforce is able to properly capitalize on its value. 4.2.2.2 Stakeholder analysis In this section I will briefly name the things to take into account for every stakeholder that can take part into the Wind Flower‟s lifecycle: STAKEHOLDER TAKE INTO ACCOUNT Manufacturer Clear technical drawings Design for Manufacture (DfM) Distributor Logistics, light-weight European pallet measures Enough space for every component inside the final box Retailer Clear product specifications Customer Appearance Approach and Implementation 31 Technical information Design for Assembly (DfA) User manual Maintenance staff Design for Assembly (Easy to disassemble and assemble, standardize, etc.) Removal staff Easy to separate materials 4.2.2.3 Target group In order to focus the design more into specific features and for having more clear to whom will be the merchandise of the product aimed to, I will list some of the qualities of the ideal customer of the Wind Flower as well as other market segmentations:  Individuals concerned with the environment and eco-friendly products.  Those with enough income to afford having a smart system in their houses but aware at the same time of the importance of renewable energy.  People living in private chalets/houses with garden with an area about 700-1000 m2 – So they have enough space to place a mast for the wind turbine and a solar panel (if they get the full hybrid system).  Individuals living in households or cottages not connected to the electric grid so they may need to get power from other sources.  Living in flats with own roof but not in urban surroundings – In order for them not to have any problem with the local neighbourhood and also because no buildings around could stop the wind.  Better with a gable roof than with a flat one – So this roof‟s shape can seize the wind better and does not produce as much turbulence as a flat one when the wind hits it.  Families with children – Due to the fact that a flower shape is more related to women and children rather than to men.  Farms.  Camping and caravan sites.  Greenhouses and cultivations. Approach and Implementation 32 Image 13. Typical family model (source: see References) 4.2.3 Material research: Fiberglass Fiberglass or GRP (Glass Reinforced Plastic) is a composite material, formed from a plastic or resin matrix and reinforced later with fibers made of glass. The interesting point about this material in this project is its manufacturing properties. Different resins may then be added to fiberglass once it is woven together to give it added strength, as well as allow it to be molded into various shapes. Common items made of fiberglass include swimming pools and spas, doors, surfboards, sporting equipment, boat hulls and a wide array of exterior automobile parts. The light yet durable nature of fiberglass also makes it ideal for more delicate applications, such as in circuit boards (Johnson, 2014). Fiberglass may be mass-produced in mats or sheets or custom-made for a specific purpose. A new bumper or fender on an automobile, for example, may need to be custom-made to replace a damaged area, or for the production of a new model. For this, one would create a form in the desired shape out of foam or some other material, then layer a fiberglass coated in resin over it. The fiberglass will harden, then can be reinforced with more layers, or reinforced from within. But a massive sheet of a fiberglass and resin compound may be manufactured and cut by machine (Johnson). Image 14. Fiberglass matrix (source: boatdesign.net) Approach and Implementation 33 Seeing all the applications and possibilities of fiberglass, there should be no problem or restrictions for the design of the required pieces of the Wind Flower. However, I will have to take into account that the production method of this material will need open cavities in order to place the plastic matrix into each of the halves‟ mold. 4.2.4 Functional Analysis (FA) This was developed to check all the functions implied and their relevance in the product. The Functional Analysis will be of great help in the ideation phase in order to prioritize decisions. The way of doing a FA starts stating a verb and a noun that describe a function, and then classifying this function in one of four classes: Primary (P), in case the function implies the objective that the product was made for; Necessary (N), if it must be implemented in the product to make it work effectively; Desirable (D), when it is not a primary or necessary function but provides additional value to the product; and finally Unnecessary (U), if it has no relevance in the design. Below is a table identifying each component of the Wind Flower, its classification, and the appropriate action to take. VERB NOUN CLASS ACTION Protect Bracket D Good sealing Hide Bolts D Put them as deep as possible Improve Aesthetics P (as requirement of the company) Complement Wind Flower‟s design Provide Aerodynamics N Study aerodynamic shapes Set Direction P Well attached (mainly applies for the vane) Ensure Light-weight D Thin thickness and empty spaces between the two halves Facilitate Assembly D Standardize screws & nuts Table 2. Functional Analysis of the Wind Flower. Approach and Implementation 34 4.2.5 Aerodynamics Despite the fact that I do not have extensive technical knowledge about aerodynamics, I looked for shapes that cause the least turbulence and tried to apply the best solution. What I found was that a drop-shape section would not be the kind that seizes the wind best, as I first thought. A drop shape combined with a pointy front would make the wind follow the curvature lines of the surface and therefore produce less air disruption in the tail. Hence, I will try to implement this shape in the section of the outer housing design of the Wind Flower. Image 15. Examples of aerodynamic shapes As for the vane, I read aerodynamic studies and found that the efficiency of the vane is not the same depending on the height in which it is positioned, due to the air flow around the rotor and blades. Right behind the rotor the wind speed will be lower than in upper flows because the blades take energy from the wind. In ideal conditions the wind speed behavior would be like this: Approach and Implementation 35 Image 16. Wind speed around a rotor in ideal conditions In addition, behind the rotor and above all behind the peaks of the blades, there are produced turbulences that destabilize the air (and the vane in it) and reduce the rotor power. This are behind the rotor does not follow a laminar way, but a “screw” path that increases the turbulences. Image 17. Air turbulence behind the rotor The vane plays a fundamental role and that is why its design should be thought carefully. The advantage of the Wind Flower is that it takes the good features from both kinds of turbines with rotor-orientation: leeward and windward. Leeward turbines have their rotor behind the mast. Their advantage is that they are positioned in the wind direction automatically, but they have the disadvantage that the mast interferes the wind before it hits the blades. Windward turbines have the rotor before the mast. They can seize the wind better but their drawback is that the axial force of the wind tries to take the rotor out of the wind flow due to the torque force existing because the distance from the rotor to the mast. The bigger this distance is, the bigger will be the torque force and the least efficient the wind turbine will be. The Wind Flower can have its rotor behind the mast without the disruption that it induces and also be self-oriented even without a proper vane. But as the aim is to make it the most efficient possible, I will look for the best position for the vane. Approach and Implementation 36 If the vane is inside the air tunnel behind the rotor, the wind speed there will be slower than in the flows around and the area of the vane will have to be bigger to have the same result. That is why some small wind turbine manufacturers mount it high lifted over the zone of influence of the rotor (see Image 18. Turbine with high lifted vane). In this way, its area can be reduced. Image 18. Turbine with high lifted vane As the company wants the vane attached to the holding structure, I cannot use a high lifted vane. Nevertheless, I will try to implement a vane that seizes the wind out of the zone of influence of the rotor. 4.3 Generate ideas and analysis 4.3.1 Ideation and sketching First ideas came after visiting the company and I considered different solutions for the shapes of the bracket cover and vane‟s outlines. Approach and Implementation 37 Image 19. First ideas. Later I checked how it would look like with different combinations of vanes and shapes of the bottom part of the outer housing. But first, I created a template with the basic outline of the Wind Flower. Image 20. Template and first attempts Approach and Implementation 38 Image 21. Bracket cover & Vane integrated Sketches. Image 22. Bracket & Vane separated Sketches. I also started trying to figure out how the assembly and interior would exist of the housing and vane. One thing to take into account was that the top part of the vane should be thicker in order to provide strength to the structure, but it was difficult to implement and attach to the cover. Following instructions of the company, I will have to take into account that the main outer housing that covers the bracket will be pre-assembled inside the final delivery box and the vane will be disassembled. This is important information due to the fact that each component will be assembled by two different persons, and one will be more experienced and prepared than the other. Approach and Implementation 45 Image 32. Internal view of the tube and different sections The inside of the cover will be empty but saving the thickness specified by the company for fiberglass, which is 3-4 mm. The two halves will be designed without blasting material in order to be manufactured in a more efficient and cheap way in case of using casting as a production method. 4.4.2 CAD modeling After building the bracket with the measures that Windforce provide me, I started testing with different sections and modeling methods. The programs I used to model are Autodesk Inventor Professional 2013 and SolidWorks 2013. And the rendering tool I used is KeyShot 4.2 Pro. Image 33. Bracket construction in CAD Approach and Implementation 46 Image 34. Different section attemps This was the most tricky part of the project because I had not made an outer housing before and I did not know the right software tools in a deep way. Here are some screenshots from Autodesk Inventor of the different tests of the cover shape. Image 35. View of one of the halves of the provisional outer housing Approach and Implementation 47 Image 36. Different render tests of the outer housing with KeyShot As I was not satisfied with the final appearance of the bracket cover I tried to refine the design until I had thinner thicknesses and a better looking. After finishing with the outer housing I started modeling the vane in order that they adapted to each other. Later I built the shells from the solid of the cover and also the ribs to add strength to the structure. And the same with the vane. Approach and Implementation 48 Once I had the parts required for this thesis project I built the rest of the pieces of the Wind Flower and made the final assembly. Approach and Implementation 49 4.4.3 Physical modeling At the same time I was modeling in CAD I made some trials with the bracket design in order to check proportions and work over it later on with other techniques. For modeling the bracket tube I used an automatic milling machine (See images below). The final physical model in scale 1 to 1 which will include all the elements of the final design will be done later. Image 37. Building of the bracket with the Milling Machine Result 50 5 Result In this chapter it will be shown the main results and findings of this project. The result of all this work can be seen in the next rendered images and descriptions. The final model has been rendered trying to represent the plastic properties of the fiberglass and the final colors. The colors chosen are cool gray for all the elements but the generator, that come from a supplier. A dark blue with green tones has been selected for some parts like the blades or the details on the bottom of the outer cover and the top edge of the vane. This combination of colors is harmonic and provides serenity to the whole design. The logo of Windforce has been implemented extruded in the vane surface. Result 51 The final design of the Wind Flower includes the holes for the M4 crosshead screws and nuts that will attach both shells of the vane to the outer housing and to each other shell. This will be done by the customer who will only need a standard screwdriver or other tool for crosshead screws. As for the assembly of the outer housing, it has been decided finally that both shells will be glued together around the bracket and placed into the final box. This is due to the fact that it will be the company who will make this assembly and therefore there would be useless to spend money in assembly tools when there will be no need to disassemble it again because it has no mechanical components inside or anything that can break during the product‟s life. The front edge is a bit pointy as I explained in previous steps, and the crossed section has the shape of a drop with a pointy front as well. This section varies according to the cover outline. The ribs in the inside part of the cover shells hold and protect the bracket, as well as they add additional strength to the whole structure. The vane also has some supporting material in the inside, not only the fixing points but also the main drawing of the brand logo helps adding consistency to the assembly. Result 52 The vane is formed by a top part where it evolves the cover tube and a down part that follows the path of the rear housing. This is due to the fact that the bottom part of the outer shells is too big to be covered by the vane and material would be wasted. The vane is attached to the outer housing and the bracket through 8 screws, from which 3 of the cross the bracket tube as well. The two screw holes in the bottom of the vane are attached only to the cover (see image below). Due to manufacturing features, the front part of the top outer cover is made in a separated piece so it can be assembled once the bracket has been placed inside the Result 53 housing and both shells stick together. Otherwise the bracket top part could not enter in the shell due to the circular shapes in the edges of the hexagonal outline. The final design also includes the front head piece, which covers the assembly of the blades with the mounting piece. Both designs can be seen in the images below. In the next image it can be seen an exploded view of the final assembly which includes all the elements apart from the assembly tools and the electrical components such as cables. Result 54 The assembly of the main parts designed during this thesis project can be seen in the image below. This includes both shells of the housing and vane with the bracket plus the front top cover. References 61 7 References Aurisicchio, M., Bracewell, R., & Armstrong, G. (2013). The Function Analysis Diagram: intended benefits and co-existence with other functional models. Retrieved from Workspace Imperial. Booz, A. &. (1998, 10 26). Earned Value Management Tutorial Module 2: Work Breakdown Structure. Retrieved from Department of Energy, United States of America. Bourne, D. L. (2011). Advising Upwards: A Framework for Understanding and Engaging Senior Management Stakeholders. Gower Publishing Company. Broadbent, i. F. (2004, p. 54). Cass, J. (2008, 9 26). Just Creative. Retrieved from How To Write An Effective Design Brief and Get The Design You Want!: http://justcreative.com/2008/09/26/how-towrite-an-effective-design-brief/ Certo, C. &. (2005). Modern Management (10th ed.). Pearson. Chicago Architecture Foundation. (n.d.). DISCOVER DESIGN: A Student Design Experience. Retrieved from http://www.discoverdesign.org/design/process Cox, S. G. (2005, p. 2). Cox Review of Creativity in Business: Building on the UK’s. DlhSoft Gantt Chart Library. (n.d.). DlhSoft. Retrieved from Product Information. Don Kumaragamage, Y. (2009). Design Manual Vol. 1. Entrepreneur. (n.d.). Entrepreneur. Retrieved from Competitive Analysis: http://www.entrepreneur.com/encyclopedia/competitive-analysis Fthenakis, V., & Kim, H. C. (2009). Wikipedia. Retrieved from Land use and electricity generation: A life-cycle analysis: http://en.wikipedia.org/wiki/Wind_power Goodwin, K. (2011). Designing for the Digital Age: How to Create Human-Centered Products and Services. John Wiley & Sons. Institute for Geoinformatics, Münster. (2007). Westfälische Wilhelms-Universität Münster. Johnson, T. (2014). Composite About. Retrieved from Fiberglass - What Is Fiberglass: http://composite.about.com/od/fibers/a/Fiberglass-What-Is-Fiberglass.htm Jonson. (2005, p. 613). Kurtz, D. (2010). Contemporary Marketing Mason. South-Western Cengage Learning. López, I. (2009, 9). Taller de Diseño II. Models and mock-ups . Zaragoza, Spain: Universidad de Zaragoza. Munari, B. (1979). The design process. References 62 NASA. (2008, 2 7). Engineering Design Process. Retrieved from http://www.nasa.gov/audience/foreducators/plantgrowth/reference/Eng_Design_512.html#.U25qGvl_uSo Randall, Timmers, & Skies, C. (2003;2001;2003). REN21. (2011, p. 11). Wikipedia. Retrieved from Renewables 2011: Global Status Report: http://en.wikipedia.org/wiki/Wind_power Rouse, M. (2007, 5). TechTarget. Retrieved from Gantt chart. Schwarzfischer, K. (2011, Vol. 33). The Aesthetic Meaning of Syntactic, Semantic and Pragmatic. Retrieved from Gestalt Theory: http://gth.krammerbuch.at/sites/default/files/articles/06_Schwarzfischer_KORR.pdf Simon, H. (1969). The Sciences of the Artificial. Cambridge: MIT Press. Sullivan, L. (1896). The Tall Office Building Artistically Considered. University of Zaragoza. (2010). Slides of the course Design Workshop. Degree in Industrial Design and Product Development . Zaragoza, Spain. Williamson, K. (2002). Research Methods for Students, Academics and Profesionals: Information Management and Systems. Wagga Wagga, NSW. Wind Energy Foundation. (2014). Wind Energy Foundation. Retrieved from History: http://www.windenergyfoundation.org/about-wind-energy/history World Wind Energy Association. (2013). 2013 SMALL WIND WORLD REPORT Update. Retrieved from Summary: http://www.wwindea.org/webimages/SWWR_summary.pdf References for some of the images: Image 1. House with hybrid system installation (source: see References): http://windforce.se/egenel.php Image 6. The three sub-types of wind turbines (sources for images: see References, 7).: http://en.wikipedia.org/wiki/Wind_turbine Image 13. Typical family model (source: see References) http://www.gardencitymft.com/imgs/happyFamilyRS.jpg Image 15. Examples of aerodynamic shapes: https://www.google.es/search?q=aerodynamic+shapes&rlz=1C1AVSA_enES423ES423 &es_sm=122&source=lnms&tbm=isch&sa=X&ei=JFyU7WqCq7P4QTqyYHgCA&ved=0CAgQ_AUoAQ&biw=1366&bih=653 References 63 Image 16. Wind speed around a rotor in ideal conditions, Image 17. Air turbulence behind the rotor, Image 18. Turbine with high lifted vane: http://www.amics21.com/laveritat/introduccion_teoria_turbinas_eolicas.pdf Image 24. DfA progression example.: http://outreach.ewu.edu/share/courses/pnemetzmills/2009opsm330/OMCh3/RTF5_5. gif Image 25. Feminine objects' examples.: https://www.google.es/search?q=female+objects&rlz=1C1AVSA_enES423ES423&es_s m=122&source=lnms&tbm=isch&sa=X&ei=y91yU7W7H6v64QSj84GwBQ&ved=0CA gQ_AUoAQ&biw=1366&bih=653#q=feminine+objects&tbm=isch http://www.examiner.com/article/best-toys-guide-releases-2012-holiday-hot-toys-list Image 26. Garden tools' examples: http://www.yell.com/biz/aj-mowers-hitchin901471182/ Image 27. Color communication (connotations): https://www.google.es/search?q=color+communication&rlz=1C1AVSA_enES423ES42 3&es_sm=122&source=lnms&tbm=isch&sa=X&ei=wuByU7jzOZSq4gSd8oCQCA&ve d=0CAgQ_AUoAQ&biw=1366&bih=653 Last images. Rendered examples of households: https://www.google.es/search?q=house+with+solar+panels&rlz=1C1AVSA_enES423E S423&oq=house+with+solar+panels&sourceid=chrome&es_sm=122&ie=UTF-8 Attachments 64 8 Attachments Attachment 1 Work Breakdown Structure Attachment 2 Gantt Diagram Attachment 3 Competitors‟ descriptions Attachments 65 Attachment 1 Work Breakdown Structure Attachments 66 Attachment 2 Gantt Diagram Attachments 67 Attachment 3 Competitors‟ descriptions Attachments 68 Attachments 69