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Isaac R. Jones December 7, 2011 Dr. Don Cripps
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Isaac R. Jones [email protected] December 7, 2011 Dr. Don Cripps Department of Electrical and Computer Engineering Utah State University Dr. Donald Cripps: I have included my final report of my senior project for your review. Our team has completed the wind turbine system. Our system consists of a graphical user interface that is available via the internet at turbine.ece.usu.edu. We are monitoring the basics of a wind energy system that include: wind speed, wind direction, power output, total power output and temperature. Also we are tracking the outputs over time to monitor trends of the system. The attached report documents the preliminary design, our design implementation, our results and other details of our system. Energy is in high demand and will only become more so as time goes on. To supply that demand a renewable resource such as the wind is an easy choice when compared to the rising costs of non-renewable resources. With the monitoring capabilities of our system the end-user can view outputs in real time. Recording and tracking output data could validate or discourage future wind energy projects in Logan, Utah around the Utah State University campus. Wind energy data is commonly used in this fashion to determine if larger turbines will be a successful renewable energy option. Our team consists of eight undergraduate electrical and computer engineers that are contributing as part of Dr. Doran Baker’s ECE 5930 class. Please feel free to contact me for any additional information you may need. Thank you for your considerations of this project. Respectfully, Isaac R. Jones And the team: Michael Engh Troy Garrett Dan Kunz Alvin Kang Michael Tait Jonathan Jensen Chris Jensen 2011 Wind Turbine Systems: Renewable Energy Implementation Signature: Dr. Don Cripps 12.16.2011 Signature: Dr. Doran Baker 12.16.2011 i Isaac R. Jones Utah State University 12/16/2011 Acknowledgements We would like to thank Dr. Doran Baker, from the ECE department at Utah State University, for making this project possible. By providing the special topics study class he provided a means for me to accomplish my senior project in a field of study that I found extremely interesting. Thank you to Dr. Donald Cripps and Laura Vernon for their counsel and advice to make the whole process as enjoyable as possible. Your help is very much appreciated. We would like to thank the sponsors of this project and those who donated their time to help bring the project together namely the Rocky Mountain NASA Space Grant Consortium for funding our project, Heidi Harper for acquiring our materials we needed in order to build, test and implement our system, Bob Carpenter from Campbell Scientific for the donation of software to monitor our system, Alan Marchant from EDL for the donation of the anemometer, Phil Baker for aiding in the construction of the wind turbine mount. Special thanks to Ty Weaver for help with the database configuration. Without his help we would still be trying to figure it out. I also would like to thank the members of the team Dan Kunz, Troy Garrett, Alvin Kang, Jonathan Jensen, Michael Tait, Chris Jensen and Michael Engh. Thank you for the effort and hard work that was put forth into this project to make the system a fully functioning energy system worthy of a senior project here at Utah State University. i Finally, we would like to thank our wives, children and loved ones for supporting us as we worked long hours away from them. ii Abstract The purpose of the project is to construct a wind turbine system that interfaces with a microprocessor. Together they store and communicate data via an information system to a website located on Utah State University campus that is used to monitor the system’s outputs. The wind turbine produces a Direct Current (DC) voltage that is utilized in conjunction with a charge controller to charge two 12-volt deep-cycle batteries that are used to power a load of two light bulbs in series. An array of sensors is monitoring weather conditions such as temperature, wind speed and direction that will indubitably correlate with power measurements of the system over time. These various outputs are being logged in a microprocessor and transmitted to a computer that updates a database which supplies our graphical user interface that the website uses where data can be monitored remotely. Our project uses a commercially available three-blade, horizontal axis, wind turbine that is mounted on the Engineering Lab Building at its highest point. This location is ideal due to its position relative to the wind coming out of Logan Canyon. Most sensors are readily available with the exception of the commutator (measures wind direction) which is a handmade sensor. The construction of the commutator is detailed in this report. The database we are using is Microsoft SQL Server 2008 and is available online as a free download. In fact many of the software components are also available online as free downloads with, once again, the exception of the graphical user interface, RTMC (Real Time Monitoring and Control). iii Table of Contents 1.0 Introduction or Background ............................................................................................................... 1 1.1 Problem Statement and Design Objectives ............................................................................... 1 1.2 Summary of Design Process Executed ...................................................................................... 2 1.3 Summary of Final Results ..................................................................................................... 2 1.4 Organization and Summary of Report ............................................................................................ 2 2.0 Review of Conceptual and Preliminary Design .............................................................................. 2 2.1 Problem Analysis ...................................................................................................................... 3 2.1.1 Review of Problem .................................................................................................................. 3 2.1.2 Summary of Specifications ...................................................................................................... 3 2.1.3 Summary of Technical Approach ............................................................................................. 4 2.1.3.1 Data Collection Devices ................................................................................................... 5 2.1.3.2 Communication Methods ..................................................................................................... 5 ........................................................................................................................................................ 5 2.2 Decision Analysis ........................................................................................................................... 6 2.2.2A Tower Location Design .......................................................................................................... 8 2.2.3 Data Logging ........................................................................................................................... 9 3.0 Basic Solution Description................................................................................................................ 10 3.1 Schematics and Flow Diagrams .................................................................................................... 11 3.1.1 Tower Mount and Hardware ................................................................................................. 11 3.1.2 Sensors and Data Acquisition ................................................................................................ 12 3.1.3 Data Processing and Display .................................................................................................. 13 3.1.4 Software Flow ....................................................................................................................... 15 3.2 Component Level Specifications................................................................................................... 17 3.2.1 Sensors ................................................................................................................................. 17 3.2.2 Tower/Miscellaneous Hardware............................................................................................ 18 3.3 Initial System Performance Estimates .......................................................................................... 18 4.0 Design of System Components and Optimization ............................................................................. 19 4.1 Discussion of Design Details and Technical Approach ................................................................... 19 4.2 Schematics and Circuit Diagrams.................................................................................................. 20 iv 4.2.1 Temperature Sensor Circuit................................................................................................... 20 4.2.2 Voltage Divider Circuit........................................................................................................... 21 4.2.3 Commutator Circuit............................................................................................................... 22 4.3 Fabrication and Construction Specifications ................................................................................. 23 4.3.1 Tower Mount ........................................................................................................................ 24 4.3.2 Transmission Line/Battery Distribution.................................................................................. 25 4.3.3 Commutator ......................................................................................................................... 27 4.4 Summary of Final Design Results .................................................................................................. 28 5.0 Project Implementation ................................................................................................................... 29 5.1 Operational Test Results .............................................................................................................. 29 5.2 Evaluation of Results Based on Requirements .............................................................................. 30 5.3 What Changes Can Be Made to Better Meet Requirements ......................................................... 30 6.0 Final Scope of Work Statement ........................................................................................................ 30 6.1 Summarize What Has Been Done ................................................................................................. 30 6.2 Summarize What Needs to Be Done............................................................................................. 31 6.3 Future Expansions That Can Be Done ........................................................................................... 31 6.4 Lessons Learned........................................................................................................................... 32 7.0 Other Issues..................................................................................................................................... 33 7.1 Material Selection ........................................................................................................................ 33 7.2 Safety Concerns ........................................................................................................................... 34 7.3 Societal Impact ............................................................................................................................ 35 7.4 Maintenance Issues ..................................................................................................................... 35 7.6 Product Documentation ............................................................................................................... 36 8.0 Cost Estimation................................................................................................................................ 36 8.1 Estimate of System Cost............................................................................................................... 36 8.2 Estimate of Design Cost (Man hours) ........................................................................................... 36 9.0 Project Management Summary ....................................................................................................... 37 9.2 Time: Gantt Chart ........................................................................................................................ 37 9.3 Personnel: Summarize Personnel Organization (Organization Chart) ............................................ 38 10.0 Conclusion ..................................................................................................................................... 39 Appendix A: Supporting Documentation .................................................................................................. 1 Parts Spec Sheets for Commutator................................................................................................... 1 v Appendix B: Calculations ..................................................................................................................... 1 Tower Torque ...................................................................................................................................... 1 Temperature Sensor conversions ..................................................................................................... 1 Voltage Divider Equation ................................................................................................................. 2 Appendix C: Code ................................................................................................................................ 2 Microcontroller Code ....................................................................................................................... 2 MS SQL Code ................................................................................................................................... 7 C# Code ........................................................................................................................................... 8 vi Table of Figures Figure 0: Flow Chart Design ..................................................................................................................... 4 Figure 1: Wind Turbine Exploded View .................................................................................................... 6 Figure 2: Tower Mount Breakdown ......................................................................................................... 8 Figure 3: Tower Mount Dimensions ....................................................................................................... 12 Figure 4: Home Page Display ................................................................................................................. 14 Figure 5: Hourly Trends Page Display ..................................................................................................... 15 Figure 6: Software Flow Diagram ........................................................................................................... 16 Figure 7: Temperature Sensor Schematic............................................................................................... 20 Figure 8: Voltage Divider ....................................................................................................................... 21 Figure 9: Commutator Schematic .......................................................................................................... 23 Figure 10: Transmission Wiring Diagram ................................................................................................ 25 Figure 11: Commutator Sensor .............................................................................................................. 28 Figure 12: Comparator Switch Schematic............................................................................................... 32 Figure 13: Gantt Chart ........................................................................................................................... 38 Figure 14: Project Management Teams ................................................................................................. 39 Figure 15. Wind Speed to Power Conversion ........................................................................... Appendix 2 vii List of Tables Table 1 ……………………………………………………………………………………………………………………………………3 Table 2 ……………………………………………………………………………………………………………………………………18 Table 3 ……………………………………………………………………………………………………………………………………19 Table 4 ……………………………………………………………………………………………………………………………………24 Table 5 ……………………………………………………………………………………………………………………………………26 Table 6 ……………………………………………………………………………………………………………………………………36 viii 1.0 Introduction or Background With the continuing fear of global warming and our effect on the environment due to our energy consumption, there is a need for innovations in the alternative renewable energy resources. The aim of this project is to study wind turbine technology and gain an understanding of the system design and engineering involved in producing electricity from the wind. 1.1 Problem Statement and Design Objectives Many states in the US are passing legislation that will force utility companies to have, in their energy production portfolios, production facilities that produce 20% of their energy using renewable resources such as wind, solar, and water. With the growing need for renewable energy solutions comes demand for engineers with understanding of system design to develop these energy production innovations. The design of this system is centered on a horizontal axis wind turbine (HAWT). The system consists of three design blocks: the tower mount, data collection, and data display. The tower mount design must take into account the different forces exerted on the turbine by the wind. The data that will be collected are: voltage output from the turbine, wind speed, wind direction, and temperature. The data will be stored in a database for easy access. Once the data is collected and processed, it will be displayed in a webpage so anyone can see the output results. 1 1.2 Summary of Design Process Executed Using a Top-Down design approach, we began the design with the turbine itself. We decided to use a horizontal axis wind turbine, mostly because we had easy access to one by purchasing the turbine from the local Lowe’s Home Improvement Store. Once we decided on the turbine type, we researched different programs that we could use to display the information that we gathered and we settled on a program provided by Campbell Scientific called RTMC Pro. This software will take data from a database and display the data as images in real time to a webpage. 1.3 Summary of Final Results Once the project was completed and functioned the way we had wanted it to we were able to monitor its outputs. There were some bugs that needed to be worked out in our calculations but they were minor. The wind turbine system monitors basic data. It has room for additional sensors if needed in the future. 1.4 Organization and Summary of Report The purpose of this document is to review the overall design, design solutions, implementation, final results, and other considerations relating to the project. 2.0 Review of Conceptual and Preliminary Design The overall design of the system will be covered by an analysis of the problem and the design analysis. 2 2.1 Problem Analysis This section will cover an overview of the problem, a summary of the specifications, and the technical approach to solving the problem. 2.1.1 Review of Problem The design specification of the project dictated that we needed a location suitable for the project, a wind turbine, data logging and a graphical user interface that would display the data. 2.1.2 Summary of Specifications Our design revolves heavily around the specifications of the wind turbine we selected. The specifications for the wind turbine are as shown in Table 1. Table 1: Wind Turbine Specifications 3 2.1.3 Summary of Technical Approach The basic design concept of the project is one that uses a dedicated computer that continually collects data from a microcontroller, stores all the data into databases, and outputs the data to a GUI. Dedicating a computer to continually collect data allows for real-time updates of the data being displayed. That way, anyone accessing the webpage will be able to see what is happening right now. Figure 0 shows the flow of our design. Figure 0: Flow Chart Design 4 2.1.3.1 Data Collection Devices One problem we needed to discuss was the method that we would use to collect the data we received from the wind turbine and various other sensors attached to the project. The selected product would need to be able to handle multiple inputs, as well as the possibility of computations on those inputs. Also, it would need to be able to easily pass along the acquired data to a storage device/service for proper analysis, display and record keeping. 2.1.3.2 Communication Methods Two methods were considered for transferring the acquired data from the wind turbine and sensors to the data storage unit. The first was via an Ethernet cable attached to the data collector near the wind turbine and to the computer where the data would ultimately be stored. The second option would be to transmit the data from the turbine over a wireless network to the computer. Both options had pros and cons. The Ethernet option would be easier to work with, as little configuration would be necessary. Power could be supplied through the Ethernet cable as well reducing the need for a complex power supply. The main drawback of the Ethernet cable is the limit on the distance that the information can travel. As the length increases, the cost of the cable will increase as well as losses to the signal due to transmission. With the wireless option, the distance is a much smaller problem because loss would have little effect over the distance we would cover. The difficulties arise in setting up the wireless network with proper signal transmitting and receiving as well as powering the component near the turbine. Power would need to be supplied through solar panels or some of the power the wind turbine provides. We decided to use the power over Ethernet method to supply power to microprocessor. 5 2.2 Decision Analysis ECE 6140/5930 is a split level course for graduate and undergraduate students. With the number of both graduate and undergraduate students roughly the same, it was decided to split the class into these two groups. Once this decision was made, the class decided to study both types of wind turbines: horizontal and vertical. The undergraduate students chose the horizontal model. This section includes a summary of design decisions that were made, along with analysis of why they were made. Figure 1 shows an exploded view of our wind turbine. Figure 1: Wind Turbine Exploded View 2.2.1 Modular Design The reason a modular construction design was chosen was based on the restrictions placed on the project by the building maintenance personnel. We were not allowed to drill holes in the roof or modify any existing infrastructure. This forced us to design a tower mount 6 that would be independent of the building itself. This also allows for easy take down and removal of the tower if it needs to be moved. 2.2.2 Tower Mount Design The structure of the wind turbine is designed to withstand the forces of the wind on the turbine as well as withstand the natural weather related elements. Also the structure needed to modular to be able to transport it to the roof. With these specifications in mind, we used a Quadra-pod design. The four legs of the Quadra-pod are made from metal tubing. Each of the four legs is connected to a center plate which has one additional upright piece of metal tubing on top to hold the wind turbine. The roof of the engineering building (where the wind turbine is located) could not be modified in any manner. Therefore the base of the turbine is attached to weather treated boards that stabilize the structure. Sandbags are placed on top of the boards as extra weight to support against the forces. Most of the parts used in construction were weather resistant. All other components that weren’t initially weather resistant were coated with weather resistant paint to serve as protection against natural weather elements. Wiring for the wind turbine runs through the center metal tube of the wind turbine and into the building through fixture made in the window. The approximate height of the wind turbine from the base to the center of the turbine is almost 11 feet. The wind turbine that we are using is a 600 Watt horizontal axis wind turbine made by Sunforce. Below in Figure 2 is a modeled structure of what we envisioned for our tower mount. 7 Figure 2: Tower Mount Breakdown 2.2.2A Tower Location Design Although there were many different buildings that could have been used to place this project, we chose the old engineering building due to its proximity to the mouth of the canyon. This allows for the greatest and most consistent wind speeds. If obstructions reduce wind speed too drastically, we have the flexibility to relocate the structure to another building rooftop. An alternative approach to the horizontal wind turbine would be the vertical wind turbine. Although this could potentially be less effective, we have decided to let the graduate level students create a vertical wind turbine. By allowing the other group to use this style, we will be able to directly compare the two different styles and note the advantages and disadvantages to each system. One of the engineering constraints we had when planning this project was anchoring the turbine. Since this was being done on a Utah State University 8 building, we are not allowed to anchor the structure directly to the roof of the building. As a result, this limits the size and height of the wind turbine. 2.2.3 Data Logging From the problem analysis above regarding the data collection devices, we narrowed our options down to two choices: a data logger provided by National Instruments or an Arduino microcontroller. The National Instruments data logger provided a simple way to monitor the data but the cost was significantly more (approximately $100). Alternatively, the microcontroller provided a less expensive method for logging the data while still offering a simple interface and programming language. While it would be more work to implement the microprocessor, we felt that it was the better choice in providing functionality and developing our programming skills. Also, from the problem analysis of communication methods also above, we decided to select the Ethernet option due to location, cost and ease of use. The Ethernet choice also meshed very well with the microcontroller selection making both choices even more certain. The main purpose of data logging is to analyze the history of our system. We wanted to display this information so that it is easy to understand and is also visually appealing. With these criteria in mind, we then decided which software package would allow us to do this with the minimal amount of code writing on our part and also be inexpensive. Campbell Scientific generously donated a copy of their RTMC Pro software (Real Time Monitoring Control), so we decided that this would be the best option for our purposes since it was free and was designed specifically to display collections of data with ease. Recording and tracking output data could 9 validate or discourage future wind energy projects in Logan, Utah around the Utah State University campus. Wind energy data is commonly used in this fashion to determine if larger turbines will be a successful renewable energy option. 3.0 Basic Solution Description As discussed earlier, the objective of this project is to create a monitoring system for a wind turbine. To accomplish this goal, we are using various sensors to monitor the environment and outputs of the turbine. Those sensors will send information to a microcontroller that will process the data and send it to a webserver. The information is then retrieved from the webserver by a database program called MySQL. The data is then stored in a database. From the database, the information is retrieved and used to update gauge and dial images set up by RTMC Pro. RTMC Pro then takes a snapshot of the images as a whole and sends the snapshots to the display website. The data from the microcontroller is sent to a webserver because it was easier to program MySQL to capture the data from the webserver than from a data file such as an Excel sheet. Sending the data to an Excel sheet and then to a database was also deemed redundant and unnecessary. Once we knew which microcontroller we were going to use, we began to collect the sensors and build their control circuits. The microcontroller we chose has six analog input pins and 14 digital I/O pins. The anemometer, temperature sensor, and the voltage divider sensor 10 circuit use the analog pins to send data. They send the data into the microcontroller as voltages. The microcontroller then interprets the voltage input and assigns data values to them. The commutator delivers a digital signal by sending zero volts for low and between four and five volts for high. There are 8 inputs that determine in which direction the wind is coming. The eight points correspond to an angle difference from one to the other of about 45 degrees. While we were in the process of building and testing the circuits, the program was being developed to interpret the data. 3.1 Schematics and Flow Diagrams The schematics of the components used in the system are discussed in finer details in this section. 3.1.1 Tower Mount and Hardware The tower mount was a major obstacle in implementing our system. A structure was needed to hold the wind turbine and be able to withstand forces from all directions due to the pivoting nature of the wind turbine as it turns into the wind. Figure 3 shows a model of the design we implemented. 11 Figure 3: Tower Mount Dimensions 3.1.2 Sensors and Data Acquisition There are three primary sensors that are being used: temperature, wind speed and wind direction. The temperature is taken by placing a single LM335 temperature sensor. This temperature takes an input (with a resistor connected to it) and outputs the temperature in degrees Kelvin for every 10 mV. Since this output is in kelvin, it is easy to calculate this into Celsius and convert that value into Fahrenheit. The temperature is sent to the microcontroller, which converts the data into Celsius and Fahrenheit and outputs that data to a website, which is used for data logging. 12 The wind speed is found by using an anemometer. It outputs 2.5 mph for every 1 Hz pulse. This data is then sent to the microcontroller. The microcontroller then does the appropriate calculations, and outputs the wind speed to the website. 3.1.3 Data Processing and Display The data we record and track will be stored in the database which RTMC Pro uses to create its visual graphics. We originally planned to use MySQL as the database platform but later learned that RTMC Pro does not communicate easily with MySQL. For this reason we converted our database over into Microsoft Server SQL or MS SQL. Even with MS SQL it was necessary to setup the database to follow a specific format which can be seen in the appendix D of this report. Once these obstacles were overcome RTMC Pro had the graphical user interface or GUI falling into place nicely. Figures 14 and 15 shows the GUI as it will be seen on the website turbine.ece.usu.edu. 13 Figure 4: Home Page Display 14 Figure 5: Hourly Trends Page Display 3.1.4 Software Flow Since we decided on using RTMC Pro for our user interface, we needed to create a database to link with this software and also write a program that will update this database with new data. We wrote a C# program to gather data from the website hosted by the Arduino microcontroller (www.ardruino.cwjensendesign.com) and then enter this information into the SQL database. We used the “try” and “catch” method when trying to insert new data into the SQL database in case the Arduino website was offline or a connection to the database could not be established so that the C# program could run continually in an infinite loop and not get errors 15 and have to be restarted manually. Once data and been successfully collected and inserted (or if an exception is thrown and therefore no data is inserted), the program then waits for approximately 50 seconds before returning to the beginning of the infinite loop where the process is repeated. Since the time it takes to open the Arduino website varies slightly (it usually takes around 10 seconds), the timestamp for each new data entry will not be equally spaced. Ideally each data entry will be one minute apart but due to the inconsistency stated previously they will sometimes be, for example, one minute and three seconds apart or 58 seconds apart. Figure 12 shows a basic flow diagram of how the software and hardware components interact with one another. Figure 6: Software Flow Diagram 16 3.2 Component Level Specifications In summary this section discusses the components used in the project and how there specification met our design plans. 3.2.1 Sensors The temperature sensor that is used to data log the temperature is the LM335. The LM335 is a diode temperature sensor that outputs the temperature as a voltage based on the actual temperature. This design was chosen because it was the most simple and offered the least amount of problems. The LM335 has an initial 1°C accuracy, 1 ohm dynamic impedance, and over 200°C coverage. The LM335 uses a TO-92 plastic package, which is rated to go from −40°C to +100°C. The Inspeed Vortex wind sensor is an extremely simple sensor. It has one input, and one output. The input is suggested as a 3-5 VDC, and outputs 2.5 mph/Hz. This sensor was chosen due to the fact that it was donated by Inspeed for use in the project. The Inspeed Vortex wind sensor has a 3 cup rotor on top with a reed switch and magnet that provides 1 pulse per rotation. It’s approximately 5 inches in diameter and is rated from 3 mph to 125 mph. 17 3.2.2 Tower/Miscellaneous Hardware The wind turbine arrived with its own specific parts for assembly. We needed to purchase parts for the tower mount and transmission lines. Other hardware pieces, such as electrical conduit, fittings, wiring, digital logic chips, electrical circuit components, etc. were purchased as needed from the ECE store and local hardware stores. The package contents are shown in Table 4 below. Table 2: Package List 3.3 Initial System Performance Estimates What we expect to see from the system is that the turbine will keep the batteries charged enough to light the light bulbs we have hooked up for the load. We will know if the 18 system is working if the lights stay lit. If not, we will know that the location does not provide enough wind for our system. 4.0 Design of System Components and Optimization In this section we will discuss the different approaches to the component design with specific requirements in mind. 4.1 Discussion of Design Details and Technical Approach The design of our tower mount was well planned in the sense that all major issues such as operational safety, structural integrity and environment specifications were considered before implementation or construction of our design began. The calculations shown below in Table 6 were used to determine the force on the wind turbine for a certain velocity. This was a very important part in determining that the structure was strong enough to withstand the forces acting directly on it. Table 1 shows the calculated force and torque on the wind turbine structure. It was for this reason that we reinforced the base of the structure with sandbags to help anchor it to the roof. For more detailed information on the equations used please refer to Appendix B: Calculations under the Tower Torque section. Table 3: Wind Speed Force 19 4.2 Schematics and Circuit Diagrams The following sections contain the circuit diagrams for each of the components that were constructed. 4.2.1 Temperature Sensor Circuit In Figure 7 it is clear why we chose to use this sensor to measure temperature. Its simplicity, however, is not the only reason we chose the LM335. The LM335 is readily available and inexpensive. Figure 7: Temperature Sensor Schematic 20 4.2.2 Voltage Divider Circuit The voltage divider used in the load circuit is to measure the voltage to the load. The load voltage can be anywhere from 0V to 24V, but the data logger can only accept a range from 0V to 5V. The voltage divider is designed to decrease the load voltage to an acceptable range for the data logger. The ratio for the voltage divider is 1/6 times the input. In this case, the input voltage is the load voltage and the output voltage is the data logger voltage. This way, when the voltage to the load is 24V, the data logger will read 4V. Figure 8: Voltage Divider 21 4.2.3 Commutator Circuit The commutator uses digital logic to send signals to the microcontroller. On the top of the commutator is a weather vane that rotates with wind direction. There is a ground wire attached to the rotating arm that will make contact with stationary wires. When contact is made, a ground signal is sent to a 2-input NAND gate. The second input of the NAND gate is tied to a positive 4.5V power supply. The low inputs to the NAND gates all have pull-up resistors that force about 1.5V into the inputs. This keeps the gates from sending bad data based on floating grounds. Once the ground signal is received by the NAND gate, a high output signal is sent to the microcontroller for processing. The following figure is a schematic of the circuit diagram for the commutator. 22 Figure 9: Commutator Schematic There are eight 2-input NAND gates that are assigned to a wind direction based on a change of direction of about 45 degrees. The microcontroller receives the signals from the NAND gate outputs using digital input pins. The signal is assigned a direction in degrees based on North being 0 degrees. 4.3 Fabrication and Construction Specifications In this section we go over parts and material used in the construction of our project. 23 4.3.1 Tower Mount The forces acting on the tower mount can be significant under the right circumstances. In order to make our structure sturdy enough we used metal tubing and other metal components to secure the mount. The metal structure was then attached to a wood base using weather treated lumber. Sandbags were then placed on the corners of the base where the feet of the tower are attached to ensure the tower does not blow over. Below in Table 5 are the materials acquired to construct the tower mount. Item Quantity 10’ 1” black metal tubing 4 1” black 45 degree elbow 8 1” galvanized floor flange 4 60 lb. Tubular sandbags 8 2” x 10” x 12’ weather treated boards 4 Table 4: Tower Mount Materials The design allowed for minimal use of parts in order to construct the wind turbine mount. 24 4.3.2 Transmission Line/Battery Distribution The transmission wiring is configured as shown below in Figure 10. The wind turbine outputs an AC voltage; it then goes to the MPPT (Maximum Power Point Tracker) where it is rectified. The DC voltage is connected to the amp meter and the two 12 volts batteries in series creating 24 volts. The load is connected parallel to the batteries charging circuit. Figure 10: Transmission Wiring Diagram The specifications for the MPPT are shown below in Table 5. 25 Table 5: MPPT Specifications There are many different kinds of batteries that could have been used for this project. The best option for performance would have been deep cycle lead acid batteries. These would allow for maximum storage and discharge. However, due to the cost of these components and the budget of the project, we decided to use typical automotive batteries. Dr. Baker was able to find two free ones that we could use. This allowed us to reduce the overall cost of our project. One alternate option for using the power generated would have been to put the power back on the grid. However, due to liabilities, we decided to keep the generated power separate. By keeping the generated power separate, we were able to reduce costs associated with a certified electrician, as well as not having to purchase the additional equipment to tap into the existing grid. 26 4.3.3 Commutator The commutator was assembled using spare parts from other projects. The center cylinder that rotates was built using a bicycle wheel hub. Wires were then strung through the existing spoke holes. From there, a ground wire was attached to the spinning bolt that rotates around the center cylinder and makes contact with the strung wires. The center cylinder is secured to the top of a box that was specially built to house the sensor. All the wires from the cylinder run down the inside of the box to the digital circuit. The circuit was put together using a printed circuit board. The circuit board is secured to the bottom of the box. The output wires from the NAND gates are then connected to an Ethernet jack that is mounted on the outside of the box. An Ethernet cable is then attached to the jack and run from the sensor down into the lab inside the building. A second Ethernet jack receives the cable and then wires are run from the jack to the microcontroller. Using the jacks allowed for secure connections for the output wires from the NAND gates and the inputs of the microcontroller. This way, no wires will be pulled out from the digital circuit. The power supply for the circuit is a set of three AAA batteries connected in series to supply 4.5V. The battery supply is also mounted on the outside of the box so that a change of batteries is easy. Figure 11 is a picture of the finished commutator. 27 Figure 11: Commutator Sensor 4.4 Summary of Final Design Results The sensors we decided to use work well within the accuracy needed for the project. For example it is difficult to calibrate the temperature sensor effectively due to the solar radiation coming off of the building during the daylight hours. This causes an error of up to eight degrees Fahrenheit. During the night, however, the temperature is accurate within two-tenths of a degree Fahrenheit. The commutator was a great addition to the project and has eight points of accuracy, meaning it is able to identify wind direction on a compass rose with a 45 degree separation difference. This was acceptable because it gave us the eight major directions, North, North East, East, etc.. Anymore information would have been overkill for the project. 28 5.0 Project Implementation In this section we discuss how the project came together, what are findings were once the project designs were completed and any problems we had on the way. 5.1 Operational Test Results Upon completion of the turbine mount and its installation, we were able to connect an oscilloscope to the output of the transmission line to see the output from the turbine. The turbine produces a three phase AC voltage. The magnitude of the output is dependent on the speed of the wind. After hooking the output transmission line to the charge controller we were able to see the DC converted voltage. When the batteries were installed, a constant 24V DC was observed on the output of the controller. This was expected. The batteries drive the 24V through the output for power use. Without the batteries, a variable DC voltage will be output based on the voltage input from the turbine, which is dependent on the wind speed. Once all the sensors were completed and installed, we began to get data from the microcontroller. Initially there were problems with the coding of the data inputs that resulted in erroneous data. Once those bugs were fixed, data began streaming fine. However, because of the difficulty in isolated the temperature sensor from other heat sources, such as the building or the sun itself, we are not getting accurate temperature data. All the data seems to be about 20 degrees higher than the actual air temperature. Now that all the bugs have been fixed, the data is being stored in an SQL database. From there the data is being sent to the website just fine. 29 5.2 Evaluation of Results Based on Requirements The results of the project implementation match up well with the system requirements. We are receiving data from the anemometer, commutator, temperature sensor, and the voltage divider with good accuracy, apart from the temperature sensor, and we are logging the data. The display website took a little while to create and implement, but it is also running at full speed. The requirements have been met well. 5.3 What Changes Can Be Made to Better Meet Requirements The power output from the turbine that we are getting is based on a mathematical approximation based on information provided by the manufacturer. To better meet the requirements we need to come up with a way to measure the AC voltage and current from the turbine output and calculate the power output based on the actual data received. 6.0 Final Scope of Work Statement This section summarizes what has been completed, what needs to be done and what can be done to the system in the future. 6.1 Summarize What Has Been Done The project can be broken down into six phases. First, we made a preliminary design of the system. Second, we purchased and acquired the bulk of our material (wind turbine, Arduino, software, etc.). Third, we constructed the tower mount on site. In phase four we assembled and connected our hardware together. In phase five we coded our software to implement the data logging scheme we designed and did some debugging along the way. This 30 phase also includes setting up our database in MS SQL and configuring RTMC to work with our database. In the final phase, phase six, we are going live with testing the logging of our data while anticipating any extraneous events we haven’t planned for that may cause a failure in the system. 6.2 Summarize What Needs to Be Done The system will be continually running making it necessary that the system be well documented to help future users of the system. This report will serve as a reference to those who will modify or use the system in any future work. Any additions to the system should be well documented and appended to this report. 6.3 Future Expansions That Can Be Done In order to help protect the battery bank from discharging too much, a limit comparator switch will be installed that will limit the amount of discharge the batteries experience due to the load. The following circuit shows how this will be done. Another future addition to the project will be to install a web camera on the roof that will show live feeds of the weather station and the turbine. This feed will be uploaded to the website as well. 31 Figure 12: Comparator Switch Schematic http://www.electronicdesign.com/files/29/6166/figure_01.gif This circuit will prevent the batteries from discharging too much by switching the load off when a certain voltage is reached. When the load is switched off, there is no current flow, and therefore, no more drain on the batteries. 6.4 Lessons Learned The method we used to decide how to display the data only considered the overall requirements needed to implement each choice. We did not realize how much knowledge about SQL was needed in order to create a database from scratch so most of the time spent trying to create a database was spent in frustration and little progress was made. Luckily, we 32 were able to find help from Ty Weaver who helped set up the weather station on USU campus and he guided us through the necessary steps to get a database up and running. Without his help, we probably would not have been able to create our database and therefore would not have been able to use RTMC Pro. So, we would have had find another method for recording and displaying the data and only had a few weeks to do so. The lessons we learned are: 1) It is always good to have a backup plan and alternatives before we actually need them. 2) When making important design decisions it is important to consider a more in depth analysis of each choice before making our final decision and what resources are available to help us with aspects we are unfamiliar with. 7.0 Other Issues This section will cover specific design specifications based on materials available and safety concerns. 7.1 Material Selection The material that we chose for the turbine mount was galvanized steel. This material is more costly than iron pipe, but it is already water resistant and will last much longer than the iron will. It is also a stronger material which helps with the stability of the tower. 33 The transmission line we chose is a large 6 AWG wire. The large wire will allow the maximum voltage to arrive at the battery bank inside the building by reducing the amount of resistive loss. We decided to run the transmission line into the building to the batteries rather than having the batteries on the roof. This necessitated the large gauge of wire. 7.2 Safety Concerns The biggest safety concerns that we have for the system is the overall stability of tower. The question of whether or not the tower will withstand all the force provided by the wind can only be answered by testing the tower with a large force. Not wanting to destroy the tower in a test, we didn’t actually test the maximum force the tower can withstand. The tower design limits the possibility of falling over or breaking because of the wind force. To further protect the tower, we placed eight 60 pound sandbags on the base boards; two on each corner. With the added weight, we felt that the chances of the tower blowing over are very slim. Another safety concern that we had while designing the tower was physical injuries to people working on the tower. The turbine blades are rather sharp and can cause significant injury if someone got too close. To help prevent these kinds of injuries, we made the tower height tall enough that an average 5’10” person would have trouble reaching the blades without a ladder. Anyone walking beneath the tower will be well out of reach of the blades as the spin. Electrical shock is also a concern when working with transmission lines and power transfers. To help reduce the risk of shock we placed protective boxes over the terminal 34 contacts of the batteries so accidental contact would be eliminated. All other wiring has very little exposed wire and the exposed sections are close to components. Accidental contact with exposed wires is very limited. 7.3 Societal Impact The importance of our project lies in the fact that we all use electricity. Energy demand will only continue to grow with time. It is estimated that by the year 2030 wind energy will make up 20 percent of our total energy produced in the United States according to the Department of Energy (“20% Wind Energy by 2030 Increasing Wind Energy’s Contribution to U.S. Electricity Supply.” http://www.osti.gov/bridge. Department of Energy. July, 2008. December 7, 2011.) With the increasing demand of energy our project provides energy to a while monitoring the system’s output. Monitoring the data in this fashion could prove or disprove a viable wind energy site before larger wind turbines are put in place. Having an alternative method of monitoring data may appeal to some in certain applications. Like any investment it is important to diversify and wind energy will be an important addition to our future’s investment in energy. 7.4 Maintenance Issues Maintenance of the system should be relative easy. Operation checks will need to be performed every once in a while, perhaps annually, on the turbine itself. All the sensor hardware will need to be checked about as often as the turbine to make sure all is working well. The batteries on the commutator will need to be changed periodically to ensure good data. 35 7.6 Product Documentation This document provides very thorough documentation of the overall system as well as the component level specifications. This documentation will always be available to future users to use as a reference. It will be kept with the system in the lab. 8.0 Cost Estimation This section details the cost of the system both monetarily and in man hours. 8.1 Estimate of System Cost The budget goal was to keep the project under $2000. Table 6 shows the system cost breakdown. We were able to keep the costs low enough to reach our goal Table 6: Cost of Materials 8.2 Estimate of Design Cost (Man hours) Many of the areas in the project were new to some of the team members, which required more time be put in to accomplish the assigned tasks. The time spent learning new material is included in the man hours as shown in Table 7. 36 Table 7: Man Hours 9.0 Project Management Summary This document provides very thorough documentation of the overall system as well as the component level specifications. This documentation will always be available to future users to use as a reference. It will be kept with the system in the lab. This section covers the time management of the project as well as team organization. 9.2 Time: Gantt Chart The project organization was split into many parts with each having start and finish times. As the semester moved forward, items were shifted to allow for more time or less if we finished parts early. Figure 13 shows the Gantt chart that was developed and edited through the course of the semester. 37 Figure 13: Gantt Chart 9.3 Personnel: Summarize Personnel Organization (Organization Chart) The project team was split into smaller teams which managed the design of their assigned parts of the overall system. Figure 14 shows how the system modules were divided amongst the team. 38 Figure 14: Project Management Teams The team members included Michael Engh, Daniel Kunz, Jonathan Jensen, Chris Jensen, Michael Tait, Alvin Kang, Isaac Jones, and Troy Garrett. Each team member chose a subsystem and managed the design of that specific subsection. The other members of the team assigned to the subsystem were there for support. 10.0 Conclusion With the energy demands of the world raising with the passage of time it is necessary that we further expand into alternative energy resources. Wind energy is one of the fastest growing options for renewable energy in the United States. It becomes more and more 39 necessary to evaluate locations for new wind energy projects. Our project represents an alternative method to monitor an area’s potential as a viable wind energy site. It also acts as a means to monitor consumer home wind energy projects to see the outputs and assess whether an additional turbine should be used due to the success of the first. It all comes down to having usable data coexisting with a wind turbine in real time. 40 Appendices Appendix A: Supporting Documentation Parts Spec Sheets for Commutator The commutator used the following parts for the digital circuit. • • • • • • 2 – Quad 2-input NAND Gate 74LS00 Chips 8 – 1M Ohm resistors 2 – Ethernet cable jacks 1 – 40 ft. Ethernet cable 1 – AA battery pack 3 – AA batteries Appendix B: Calculations Tower Torque 𝐹(𝑁) = �𝐴𝑖𝑟 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 � 𝐾𝑔 𝑚 �� ∗ [𝑅𝑜𝑡𝑜𝑟 𝐴𝑟𝑒𝑎 (𝑚2 )] ∗ [𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 � �]2 3 𝑚 𝑠 𝑇=𝐹𝑋𝐻 𝑚 = (MPH) ∗ (.447) 𝑠 Temperature Sensor conversions temp = (digital/1024); temp *= RefVoltage; temp = (temp * 100.0); temp -= 273; tempF = (temp * (9.0/5)) + 32; 1 Voltage Divider Equation 𝑉𝑜𝑢𝑡 = 1 ∗ 𝑉𝑖𝑛 6 Power Calculations By linearizing the curve shown in Figure 15 we were able to approximate power output at a given time given a certain windspeed. Figure 15. Wind Speed to Power Conversion Appendix C: Code Microcontroller Code /* Web Server A simple web server that shows the temperature windspeed and power of the Wind turbine assembled by USU students Circuit: * Temperature Sensor Connected to A0 - A1 * Anemometer Connected to A2 * Voltage in Connected to A3 * Wind Vein Connecter to D2-9 */ 2 #include"); // output for debugging only client.print("digital reading is "); client.print(digital); client.println("
"); client.print("Temperature TWO in C is "); client.print(temp2); client.println("
"); client.print("Temperature ONE in C is "); client.print(temp); client.println("
"); client.print("Farenheit reading is "); client.print(tempF); client.println("
"); client.print("Power reading is "); client.print(power); client.println("
"); client.print("Pin that was last active high for wind direction: "); client.println(windDir-1); client.println("
"); client.print("Wind Direction is "); client.println(windDirChar); client.println("
"); client.println("
"); client.print("Cycles per 10 seconds are "); client.print(cycles); client.println("
"); client.print("Wind Speed is "); client.print(windSpeed); client.print(" mph"); client.println("
"); client.println("input pin 7: "); 6 client.println(digitalRead(7)); client.println("
"); client.println("input pin 6: "); client.println(digitalRead(6)); client.println("
"); client.println("input pin 5: "); client.println(digitalRead(5)); client.println("
"); client.println("input pin 4: "); client.println(digitalRead(4)); client.println("
"); client.println("input pin 3: "); client.println(digitalRead(3)); client.println("
"); client.println("input pin 2: "); client.println(digitalRead(2)); client.println("
"); client.println("input pin 1: "); client.println(digitalRead(1)); client.println("
"); client.println("input pin 0: "); client.println(digitalRead(0)); break; } if (c == '\n') { // you're starting a new line currentLineIsBlank = true; } else if (c != '\r') { // you've gotten a character on the current line currentLineIsBlank = false; } } } // give the web browser time to receive the data delay(1); // close the connection: client.stop(); } } MS SQL Code Here are a few example of the SQL query language that was used throughout the project to make changes to the database. SQL Commands //Change Column; exec sp_rename @objname = 'weather.dbo.CR3000_Final.Amps', @newname = 7 'WindDirection', @objtype = 'COLUMN' //Change cells within a column UPDATE weather.dbo.LNDBColumnMeta SET lnColumnName = N'WindDirection', dbColumnName = N'WindDirection' WHERE lnColumnName = N'Amps' AND dbColumnName = N'Amps'; // adding column into table ALTER TABLE weather.dbo.CR3000_Final ADD TotalPower decimal //adding row into table INSERT INTO weather.dbo.LNDBColumnMeta (columnID, LNDBStationMeta_stationID, LNDBTableMeta_tableID, lnColumnName, dbColumnName, process, units, dataType, columnOrder, active) VALUES (185, 1, 2, N'TotalPower', N'TotalPower', N'Smp', N'', 7, 0, 1); //changing column type ALTER TABLE weather.dbo.CR3000_Final ALTER COLUMN TotalPower real C# Code using using using using using using using System; System.Collections.Generic; System.Linq; System.Text; System.Data.SqlClient; System.Net; System.IO; namespace WeatherUpdater2 { class Program { //public static double ToDouble(string value); static int counter; static int divisor; static double power; static double sumpower; static void Main() { divisor = 60; counter = 60; power = 0;//set value from database query instead sumpower = 0; while (true) 8 { //string URL="arduino.cwjensendesign.com"; TryCreateTable(); System.Threading.Thread.Sleep(50000); } } static void TryCreateTable() { //DateTime Timestamp; string Timestamp = DateTime.Now.ToString("MM/dd/yyyy HH:mm:ss"); //char[] badchar = { 'P', 'M', 'A' }; //Timestamp = DateTime.Now; //string newTimestamp=""+Timestamp+""; //string finalTimestamp = newTimestamp.TrimEnd(badchar); Console.WriteLine(Timestamp); try { string URL = "http://arduino.cwjensendesign.com/"; HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(URL); myRequest.Method = "GET"; WebResponse myResponse = myRequest.GetResponse(); StreamReader sr = new StreamReader(myResponse.GetResponseStream(), System.Text.Encoding.UTF8); string result = sr.ReadLine(); //string nextresult = sr.ReadLine(); //This will read next line sr.Close(); myResponse.Close(); Console.WriteLine(result); // Console.WriteLine(nextresult); char[] delimiterChars = { ',' }; //string text = "one\ttwo three:four,five six seven"; // System.Console.WriteLine("Original text: '{0}'", text); string[] words = result.Split(delimiterChars); // System.Console.WriteLine("{0} words in text:", words.Length); sumpower += Convert.ToDouble(words[0]); Console.WriteLine(words[2]); Console.WriteLine(Timestamp); //Order:Power,WindSpeed,Temperature,WindDirection if (counter == 60) { if (divisor != 0) power += sumpower / 60.0; sumpower = 0; counter = 0; divisor = 60; } counter++; string teststring = "INSERT INTO weather.dbo.CR3000_Final (TmStamp, RecNum, Temperature, Windspeed, Power, 9 WindDirection,TotalPower) VALUES ('" + Timestamp + "',1 ," + words[2] + "," + words[1] + " ," + words[0] + " ," + words[3] + "," + power + ")"; Console.WriteLine(teststring + "\ncounter = " + counter); Console.WriteLine("\ndivisor = " + divisor); // foreach (string s in words) // { // System.Console.WriteLine(s); // } using (SqlConnection con = new SqlConnection( WeatherUpdater2.Properties.Settings.Default.weatherConnectionString)) { con.Open(); try { using (SqlCommand command = new SqlCommand(teststring, con)) //using (SqlCommand command = new SqlCommand("INSERT INTO weather.dbo.CR3000_Final (TmStamp, RecNum, Temperature, Windspeed, Voltage, Amps) VALUES ('11/21/2011',1 ,9,35 ,2 ,7.5)", con)) { command.ExecuteNonQuery(); Console.WriteLine("we made it..."); } } catch { Console.WriteLine("Table couldn't be created."); } } } catch { Console.WriteLine("Couldn't connect to website."); divisor--; } } } } 10