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Go to the Intro
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Intro Meet the Sun Tracker Challenge!
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David and Michael Hartkop, owners of Solar Roast Coffee LLC,
cordially invite YOU to participate in the 2009 Sun Tracker Challenge! |
| The Problem: Solar Roast Coffee uses a solar concentrator to provide heat to roast their coffee beans. Currently, the array of mirrors must be manually adjusted every 3 minutes to follow the sun through the day. This is a hassle, and is not very efficient! |
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Your Team's Mission: Design and build a solar tracking system that can keep the Helios-4 Solar Concentrator aimed at the sun through a full day of coffee roasting! |
| The Prize: Winning team receives $1000.00 cash, publication on the Solar Roast Coffee Website, and Solar Roast Coffee prizes. All top-ten finalists will will have their projects published on the Solar Roast Website, and will receive Solar Roast Coffee T-Shirts and prizes. |
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Read the Q & A
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Q&A Questions and Answers
Follow links below each Answer to find more detail!
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Q: Who can enter the Sun Tracker Challenge?
A: The Sun Tracker Challenge is open to all citizens of the U.S.A. from grade seven to adult. more about eligibility and teams
Q: Does it cost anything to enter?
A: There is a non-refundable entry fee of $50.00 per team. If your team is one of the top-ten finalists, you will be required to ship your device to Pueblo, Colorado for field-testing. more about cost to enter
Q: What does my team have to DO, exactly?
A: There are two parts to the contest: submit your proposal, and then possibly test your device. Every team must design a tracking system and submit a proposal, in order to be considered. If your team is one of the top-ten finalists, then you must BUILD your system, and ship it to Pueblo for field testing. more about contest logistics: designing, building, testing
Q: What skills does my team need to compete?
A: The Sun Tracker Challenge is primarily an ELECTRONICS and CONTROL SYSTEMS challenge. The physical solar concentrator is already built! Your task is to create a box that interfaces with it, and tells it how to point at the sun. more about the technical scope of the Sun Tracker Challenge
Q: How will my team be judged?
A: Each team's design will be judged on a points system. A design can be given a maximum of 100 points, 20 points falling in each of five categories: safety, accuracy, cost, ease of implementation, and reliability. more about rubrics for judging
Q: Does my team have to travel?
A: No, your team does not have to travel. If your team's project is one of the top-ten, however, you will be reqired to ship your device with instructions to us in Pueblo! Finalist teams are invited to visit in Pueblo during the testing phase, but it is not required. more about contest schedule of events
Q: What are the Deadlines I need to Know about?
A: Your team's initial entry form must be received no later than 3pm, April 15. You can download an entry form by clicking here: Download Entry Form (PDF)
Your team will need to submit its proposal by June 10th. You can download your proposal workbook here: Download Proposal Workbook (PDF)An expanded contest schedule can be found at the following link: more about contest schedule of events
Q: How can I ask questions that are not answered here or below?
A: Questions can be written directly to David Hartkop, Inventor of the Helios 4 solar coffee roaster and host of the Sun Tracker Challenge. Please e-mail your questions to: suntrackerchallenge@solarroast.com. Please DO NOT call Solar Roast Coffee with questions about the Challenge. You would simply be calling our retail coffee shop, and they really don't have anything to do with the contest! E-mail really is best.
***Also, once your team has officially applied, you will get a secret log-in to a Sun Tracker Challenge bulletin board, where teams can share information and discussions related to the challenge.***
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Read All the Details
1.) About Solar Roast Coffee LLC
Solar Roast Coffee is an innovative coffee-roasting company started by two brothers, David and Michael Hartkop. The company's chief activity is roasting organically grown coffee using solar energy. In order to meet this goal, the brothers have constructed a series of solar roasters, since the company's start in the summer of 2004. The company currently operates an online wholesale business and a retail coffee shop in Pueblo, Colorado. Coffee is currently roasted with the company's newest and largest machine, the Helios-4. Read more about the company history online here.
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2.) About The Helios 4 Solar Concentrator
Solar Roast's newest machine, the Helios-4, consists of a large solar concentrator connected to a custom-built coffee-roasting oven.
Layout of Helios 4 Plant |
Rear layout of Helios 4 Plant |
Time series of Helios-4 Solar Concentrator. |
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The concentrator measures 35 feet across and has a surface area of roughly 20 square meters. It consists of glass mirrors attached solidly to a movable steel frame. When this mirror array is aligned precisely to the sun, it focuses sunlight (much like a giant magnifying glass) onto a thermal receiver, which heats air to temperatures as high as 900˚F. The heated air is then ducted down into a specially built coffee roasting chamber, where it provides most of the heat-energy required to roast green coffee. The Helios 4 is outfitted with a propane burner, which adds heat to the roaster as needed, especially during cloudy or cold weather. (Solar Roast Coffee LLC purchases carbon credits from renewable energy providers elsewhere, and so can claim to be 100% carbon neutral, though their production roaster is not yet 100% solar.)
The 5300-pound reflector rotates on a wheeled base through a range of 350 degrees, much like a giant turntable. The reflector array is capable of tracking vertically as well. It is lifted vertically using a winch system, and is able to track the sun from roughly 10 degrees above the horizon to the sun's highest position on summer solstice. Both the vertical and horizontal directions of motion are motorized using DC gear-motors, connected to electronic speed controllers. Currently, the array is tracked manually using a set of switches for UP, Down, Left, and Right. Position is monitored inside the solar roasting building via a small closed circuit video monitor. The monitor receives its signal from a specially built pinhole video camera mounted near the receiver. Under normal operation, the array is seen to be perfectly aligned when the spot seen on the video monitor falls in the center of the screen's cross hairs. The operator makes an adjustment to the array's position every 2 to 3 minutes when roasting. It takes between 15 and 25 minutes to roast a 10-20 pound batch of coffee. The temperatures used in the roaster vary from 450 to 550 degrees F. Read more about solar coffee roasters online here.
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3.) Technical Scope of the Sun Tracker Challenge
| Solar Roast Coffee's current solar coffee roaster is tracked manually by the operator. The operator looks at a small closed circuit video monitor, which receives a signal from the 'Solarscope'. The Solarscope is specially modified pin-hole camera, installed on the concentrator array's central tower. The Solarscope images the sun as a small dot moving against a stationary "X" of crosshairs in the background. |
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When the operator notices that the spot of light (representing the sun) is no longer centered on the monitor's cross-hairs, he/she adjusts the position of the array by activating switches for "UP", "DOWN", "LEFT", or "RIGHT", thus moving the spot of light back into position under the cross-hairs. This alignment scheme allows the array to be aligned with the sun to well within 0.25 degrees. The operator, however, must stand by and make adjustments every 2 to 3 minutes! |
| Click on the image of the Helios-4 control panel at right to get a closer look! The "Engage Auto-Track" switch is not currently connected to anything. It could be connected to YOUR tracker! The "error" light is not connected. This is technically correct, as I never make errors.
-dave ;-D
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Your tracker circuit will have direct access to the Helios-4's movement functions. It will connect to a 5-Pin DIN connector on the bottom of the main control panel.
Please click on the schematic diagram to the left in order to view an example "Push Button Controller." This schematic is a functional demonstration of how one should connect to the control box shown above. A complete set of interface specifications can be found by downloading the Proposal Workbook (PDF).
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Your team's task is to design, build, and test a solar tracker module that automatically instructs the Helios-4 array when and how to move.
Your solar tracking circuit must be enclosed in a project box. A single 110VAC outlet is provided near the control box area, just below the main control panel.
See the pictures below for details about where your project box must 'live' during testing. There are also details about where your team is allowed to install sensors and position encoders on the system.
Please download the official Proposal Workbook (PDF) for a full set of specifications and guidelines! |
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The position and size limitations of your electronic project box. |
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Locations at which you may install sensors and/or digital position encoders:All of your sensors will be installed by Solar Roast Technicians (dave). See Project workbook for detailed guidelines! |
Start Your Thinking Engines!
To start you off, you might consider that solar tracking systems are generally divided into two broad categories:
Position / Timer Based
These systems use a computer to calculate the predicted position of the sun in the sky, and use precise knowledge about the concentrator's position to determine how far and in what direction to move. Many advanced systems being developed by the National Renewable Energy Laboratory rely on this approach, as it can be extremely accurate. It requires, however, a precise reading of the concentrator's position. Since the H-4 does not currently have position sensors on either axis of movement, teams will have to devise sensor packages to be installed on the array. Details about how and where positional sensors may be installed will be included in the Official Project Packet, which will be mailed to the team. |
Feedback Based
These systems typically use a sensor that directly detects the position of the sun, and uses this information to activate motors, which move the array to a new position. Feedback systems are very promising because of their simplicity and low cost. They are typically, however, less accurate than timer based systems. Additionally, they sometimes behave erratically when confronted with unexpected conditions such as passing clouds or reflections from nearby objects. Those who wish to experiment with feedback systems may wish to use the video signal already provided by the Helios-4 closed circuit pin-hole video camera. They may alternately have their own custom-built sensors installed on the concentrator array. Details about how and where solar-position sensors may be installed will be included in the Official Project Packet, which will be mailed to the team. |
It is important for your team discuss and understand the benefits and drawbacks inhearant in the two types of tracking philosophies. You may discover that your team has talents and experiences that lend better to one approach than to the other. In any contest, it is important to play to your team's strengths!
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4.) Contest Logistics: Designing, Building, Testing
Solar Roast Coffee's call for entries into the Sun Tracker Challenge is a call for engineering project proposals. Of the many Final Project Proposals submitted to The Challenge, only ten will be selected for practical trials in Pueblo. All ten will be featured finalists, and will have their pictures and designs published on our website. Only one finalist team however will win the grand prize of $1000.00, essentially winning the contract to install their tracking system on the Helios-4 Solar Roaster.
If a team is chosen as one of the ten finalists, the team will have until September to construct and test it's actual tracking device. The solar tracking system must then be shipped to Solar Roast Coffee to be installed by a Solar Roast technician. Finalist teams are invited to travel to Pueblo in order to observe the testing of their system, but their presence is not required for the contest. All Middle-School and High-School applicants must be accompanied by their faculty advisor or a responsible adult when visiting the Helios-4 Solar Roasting Facility. Solar Roast Coffee can not pay for transportation or lodging of finalist teams, but can recommend various places to stay.
Teams are required to provide clear written/drawn instructions as to how their system is to be installed, set-up, and used! Remember, the Helios-4 is an actively used commercial solar concentrator. It is used several days per week in order to provide coffee for coffee shops, an online wholesale business, restaurants and grocery stores in the region. Your tracker MUST NOT require the system to be off-line for more than two hours of installation.
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5.) Rubrics for Judging
Solar Roast Coffee is looking for, "A reliable low-cost solar tracking system that is accurate, can cope with the changing weather of Colorado, and is made from easily replaceable/repairable parts."
A tall order! Like most real-world challenges, the solution will be the design that most adequately balances all of the desired requirements.
For 100 possible design points:
20 points: system safety -system must be safe to install and use.
20 points: tracking accuracy -system must align within +-0.25˚
20 points: system cost -no specific limit, but economical is better.
20 points: ease of implementation -should be easy to install and use.
20 points: reliability/longevity -heat, cold, ice, rain, hail, wind!
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6.) Dimensions of Design
This section, "Dimensions of Design" is intended to offer a slightly more abstract way of thinking about your design. Rather than looking at each of the judging rubrics as individual items to be addressed, I find it helpful to examine how the above considerations are interrelated.
Just as the dimensions of height, width, and depth are real considerations in the physical world, your conceptual design can be thought of as having separate dimensions. (This whole section is a metaphore and only a metaphore, so don't worry if it doesn't help you. If conceptual tools like this only confuse the issue, please just skip it!)
For sake of discussion, I have labeled the dimensions of design as follows:
| X. For the relationship between Reliability & Complexity |
Y. For the relationship between Accuracy & Ease of Installation
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| Z. For the relationship between Cost & Longevity |
Notice that, for each dimension, there is a relationship between two aspects of design. For instance, there is a relationship between Reliability and Complexity for dimension "X." It is important to recognize that these two aspects of design are, in a certain sense, competing with one another for your design resources! If your design is highly complex, for example, there is a greater chance for something to go wrong, hence lower reliability. A good design will strike a balance between the competing aspects within each dimension of design.
To help 'unpack' this concept a little more, I have expanded each dimension's relationship below, and included a 'tip' for balancing this relationship:
X. Reliability & Complexity
Think of 'Murphy's Law' which states that anything that CAN go wrong WILL at some point in the system's lifetime. Edward Murphy was a researcher doing high-speed experiments that involved sensors, crash-test dummies, and a rocket sled! One experiment dramatically failed because several of the many sensors in his test apparatus were wired incorrectly.
Design Tip: Make your system as simple as possible, while still getting the job done!
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Y. Accuracy & Ease of Installation
In order to be tested, your team's design must be easily installed on the H-4. There will be a limited amount of time for calibrating your sensors, loading your software, and/or hooking up your various connections. It may be possible for your machine to be very accurate, but this will not matter, if it takes an hour to calibrate!
Design Tip: Try to build accuracy into your design -keep the number of separate things that need installing/adjusting to a minimum! If you have sensors, make sure to use steady mounts that can quickly tighten down without having to use tools! (See sensor installation in the downloadable Proposal Workbook.)
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Z. Cost & Longevity
You should design your system to survive and to last, in case it is chosen to be used full-time! It must be able to survive outdoors in heat, and cold and moisture and dust. There will be wind, ice, and intense sunlight. It is not recommended, however, that you spend thousands of dollars to encase everything in custom-built hermetically sealed stainless capsules. NASA has the budget to do this, but their projects go to Mars, not to Pueblo Colorado!
Design Tip(s): There are many different electronics enclosures available online and from retail electrical hardware stores; plastic is fine. Seal holes and around connectors with silicone caulk. Paint outdoor components white to reflect excess sunlight. Use white or light-gray cables.
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Safety:
You may notice that safety is not specifically listed within the X-Y-Z dimensions of design. Safety is, in fact, at the top of the list of judging rubrics! None of your work in the other areas of your design matter if safety is not part of ALL of your considerations!
Getting Started:
In order to get your team started, the downloadable Proposal Workbook includes a primer to the field of solar trackers and solar concentrators. There are also some some useful engineering resources listed. Finally, there is a useful decision making tree that well help you to pin-down a design concept that will work for your team. The Proposal Workbook can be downloaded by clicking here. Happy designing!
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7.) Contest Schedule of Events
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Sun Tracker Challenge:
Schedule of Events
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April 15
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Application Deadline |
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June 10
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Final Project Proposals Deadline |
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June 15
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Ten Finalists Announced |
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(Finalists have the summer months to build and test their tracking systems on their own.)
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September 1-30
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Practical testing, to be scheduled with finalists |
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October 10
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Final Winners Announced |
Expanded Schedule
Application Deadline (April 15)
The official Sun Tracker Challenge application is downloadable from the Solar Roast Coffee website at www.solarroast.com/suntrackerchallenge. It must be filled out by the members of a team, and mailed to Solar Roast Coffee, at 226 North Main St. Pueblo CO 81003. A check for the non-refundable entry fee of $50.00 must be included for the application to be processed. All entries must be received by April 15.
Final Project Proposals Deadline (June 10)
Solar Roast Coffee must receive each team's full project proposal by this date. Teams should download the official Proposal Workbook and follow the guidelines given. The proposal includes drawings, diagrams, and a written description of the team's proposed system. The team shold also develop and propose instructions for installation of the tracker on the H-4. The final project proposal is your chance to show off your ideas and design skills! Your team is not required to have built anything at this point in the game, but practical experimentation can be extremely helpful when it comes to developing a good design!
Ten Finalists Announced (June 15)
The final project proposals will be reviewed in great detail and judged on a points basis (See Rubrics for Judging.) The proposals with the ten highest scores will be selected to be the top-ten finalists. The results and finalist selections will be viewable on the Sun Track Challenge website on June 15, at 10Am. (www.solarroast.com/suntrackerchallenge)
Practical Testing (September 1-30)
If a team is chosen as one of the ten finalists, the solar tracking system must be shipped to Solar Roast Coffee to be installed by a Solar Roast technician. Finalist teams are invited to travel to Pueblo in order to observe the testing of their system, but their presence is not required for the contest. All Middle-School and High-School teams must be accompanied by a faculty advisor or a responsible adult when visiting the Helios-4 Solar Roasting Facility. Solar Roast Coffee cannot pay for transportation or lodging of finalist teams, but can recommend various places to stay. The schedule of testing will be coordinated on a team-by-team basis closer to the testing date.
Teams are required to provide clear written/drawn instructions as to how their system is to be installed, set-up, and used! Remember, the Helios-4 is an actively used commercial solar concentrator.
It is used several days per week to produce coffee for cafés, an online wholesale business, restaurants and grocery stores in the region. Your tracker MUST NOT require the system to be off-line for more than a two hours of installation. Ideas for efficient system installation are included in the Official Project Packet.
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8.) Final Winners Announced (October 10)
The team that has demonstrated the most desirable solar tracking system will receive the contract for its use. Solar Roast Coffee will pay the winning team $1000.00 for the use of their system for a term of one year. The team can expect ongoing updates, questions, and data from Solar Roast during this extended practical trial period. Team will also receive certificates of achievement, t-shirts, and other Solar Roast prizes.
All finalists will receive a Solar Roast Coffee Sun Tracker Challenge certificate of achievement, and other solar roast prizes.
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9.) Cost To Enter
Application fee for Sun Tracker Challenge is $50.00. This fee is non-refundable, and must be sent along with the initial contest application. Fee should be sent as a check (no cash) made out to "Solar Roast Coffee LLC" and should have "Sun Tracker Challenge" noted somewhere on the check. A receipt for the entrance fee will be included in the Official Project Packet that will be mailed to team.
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10.) Eligibility and Teams
The Sun Tracker Challenge is open to all citizens of the U.S.A. from grade seven to adult. A team can consist of one to five people, plus a faculty advisor in the case of a student team. Applicants should note their "Team Type" on the application according to the status of the team members. For instance, there is an appropriate checkbox for "Middle School / High School." Student teams must have an official faculty advisor who has authority to coordinate facilities and resources of the learning institution to which students belong. Teams of mostly or entirely non-students may check "Mixed Status Team" or "Independent Engineers" respectively. Applicants will notice columns for "Area of Expertise" and "Education." Please fill these in as honestly as possible. The information will be used to create a team's key players profile, but there is no requirement for education or background. (Many important inventions and technical achievements throughout history have come from people of unlikely areas of expertise! David Hartkop, creator of the Helios 4 Solar Coffee Roaster, began building solar machines after four years of film school and two years of community college physics.) Likewise, there is no specific discrimination for age, except where safety is concerned. For reasons of safety, it has been decided that no student younger than middle-school (7th grade) may apply unless as part of a "Mixed Status Team" consisting of a majority of older students and/or independent engineers.
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11.) Safety
It is to be understood that Solar Roast Coffee is in no way responsible for personal injury or property damage that occurs as a result of an applicant team's activities. The responsibility for safety falls to those applicants who choose to participate in the contest, and to the faculty advisors of student teams. It is acknowledged that some level of mechanical and electronic fabrication must be carried out by the team in order to create a solar tracking device. It is imperative that work with tools and electricity be supervised by a faculty advisor or adult (18 + years old). Ideally, work will be carried out in a safely maintained private shop or school laboratory facility. Team members are encouraged to enlist the help of certified trade professionals whenever needed. Example: Hire an electrician or enlist one into the team! Do not attempt to do work that you do not know how to do. Electrical specifications and restrictions will be given in the Official Project Packet.
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