Integrated System Build & Test with Customer Demo
Team Vision for Build & Test with Customer Demo PhaseWith Imagine RIT quickly approaching the team, the team needed to come up with the final design so that Engineering Requirement testing could take place. This phase the team wanted to do some final tests on the broom design to make sure that it can be manufactured the easiest way possible. Also, some testing was scheduled to see the effect of adding baffles to the tank design to help with agitation. In order to have everything ready for Imagine RIT, the team wanted to pick a final Media design and purchase the appropriate chemicals needed for the expansion process.Lastly, will all of the designs falling into place, the team hoped to finally create some standard build instructions, purchase some final materials, and update the technical paper.
Project PlanAs expected with the delays in the project, the team must continue to work quickly in order to complete all the goals set from the beginning of the semester. Our plans for Imagine RIT and some of the ER testing has changed due to constraints and failure or some Spirulina medias. The team has updated the Project Plan. and the Team Budget.
Test Results summaryContinued testing was completed in order to finalize a design that the team was confident in. Improvements made in the agitation and media subsystems can be seen below. The team is hoping to begin testing Engineering Requirements. as soon as possible.
Agitation SubsystemAn important part of completing this project is to ensure that others will be able to replicate our designs. With the broom design basically finalized, the team worked on creating an outline for Work Instructions for the Broom Assembly.
The focus of this phase was on finalizing the design of the broom, final dimensions and materials, and design testing. Below are pictures of the final designs as well as deformation and stress analysis performed using ANSYS Workbench and SolidWorks. Furthermore, preparing to justify the change in the original design, the team found research papers that emphasize the importance on vertical mixing, defined as the cyclical movement of the algal cells between surface and bottom layers of the culture to achieve optimal dark-light cycles, reduce sedimentation and maximize productivity.
In order to continue testing a non-dimensional analysis was performed using the Buckingham Pi Theorem. According to the results, our model is based on Reynold's Number, Froude's Number and Drag Force. Since, we are most concerned with the vertical flow (gravitational effects and wave generation) in the system,
In order to validate our new system with our model, we must make sure we have kinematic & geometric similitude. We have scaled the tank and broom by 1/3 in all dimensions approximately for testing. According to the analysis, in order to maintain similitude we need to decrease the speed of agitation and viscosity of the medium. Since is it very hard to find other non-toxic fluids with a lower viscosity than water, it is more feasible for the team to try to decrease the speed of the broom during ER testing. Below are pictures of the analysis performed.
We estimated the amount of time required to mix one 3x6 meter tank incorporating a raceway pond central divider. The document describing the method used can be found here, as Agitation Time Quantification.
Broom DesignThe broom is made out of Oak Wood, which is found in South of India as a local resource. The design incorporates pitched blades used in turbine mixers to increase vertical flow, but was simplified to allow for easier manufacturing and greater surface area to create turbulent flow.
Tank DesignIn order to decrease the production cost, the team focused on reducing the agitation time and increasing production. Aside from the Broom Design, the team plans to modify the rectangular tanks currently used to resemble Raceway Pond (RWP) design. According to Liffman et. al, the development of a novel bend design can reduce the energy loss at a bend by around 87% relative to the energy consumed at a conventional bend [when used in a RWP with a paddlewheel]. Although our system is not automated, the team decided to incorporate baffles and a divider to reduce agitation time and create a homogeneous mixture.
Below are pictures of the final tank design. Final work instructions and ER testing needs to be done on the whole system.
Media SubsystemOutlines for creating the medias, as well as how to agitate the algae have been created but will be filled in more as the actual instructions are finalized.
The following document shows a progression of microscopic images taken of each bioreactor over the course of the media study. In each column a different media is represented and in each row a different day of the study. Changes in cell density as well as cell morphology can be observed over the time the images were taken.
A final cell count was recorded from a sample of each bioreactor. A hemocytometer was used to determine the number of spirulina and contaminant algae per unit volume. Each column represents a different media, the first row shows images at 20x magnification, the bottom row shows 40x magnification.
Using the data collected for each bioreactor graphs for optical density vs. time, pH vs. time, and cell population composition were made.
Costing UpdatesDue to many recent updates, the team decided to revisit the costing analysis done a few phases ago. The agitation system that is now being used has changed as well as the amount of time needed to agitate and the number of workers. There are still updates that will need to be made to this analysis as a final media is selected and a specific time for agitation is calculated with the new broom and tank designs. However, it is easy to see that using the more manual broom design will cut down costs of the system as compared to using the diffuser system. Click on the link to see the whole Cost Analysis.
Imagine RIT and other DeliverablesThe team continued to make updates to the Technical Paper. As final decisions are being made this week, the team hopes that more technical writing will be added to the paper next week. Due to some constraints the nature of the Imagine RIT exhibit has been changed. The team hopes that they will be able to grow up 6 tanks of Spirulina but that will obviously not be confirmed until about a week prior to the event. Also it has been decided that the team will try to use the ARS media as the control and then add cow dung to it to see if it can be a feasible supplement for all medias. The team purchases the necessary salts and materials needed to run the Imagine exhibit as well as finish the Engineering Requirement testing.
Risk Assessment and Problem TrackingBelow are images depicting updates to the Risk Analysis and Problem Tracking documents.
Design Review Materials
- Notes and Action Items from Review can be found HERE
- Peer Review for the Integrated System Build & Test Phase can be found HERE. Evaluation performed on Sunday, April 17th/2015.
- Team Shared Vision for the coming Integrated System Build & Test Phase can be found HERE. Developed on Sunday, April 17th/2015.
Plans for next phase
- Complete Media Work Instructions
- Complete All Supporting Documentation for the Broom
- Prepare for Imagine RIT
- Expand Media and Test Cow Dung approach
- Submit 70% of Technical Paper
- Complete Imagine RIT Poster
- Start/Continue ER Testing
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