P17483: Solar Transpired Collector Crop Dryer


Project Summary Project Information

Due to the surplus of crops during harvest season, farmers in Haiti are left with excess spoiled crops and low profits. A solar transpired collector crop dryer is a device for drying this excess produce in order to reduce waste of spoiled food by preserving it to be consumed at a later time. The device will help to increase profits of farmers by allowing them to sell a larger percentage of their crops and to match the supply to the demand for crops. A prototype was previously developed and proven effective, but it has not been tested in the rural Haitian environment. For this project, the current concept needs to be evolved into a robust prototype made of area-available, inexpensive materials that is capable of drying moderate amounts of fruit in a few days without damaging the dried food. The dryer must also be easy to operate, require little maintenance, and be able to withstand appropriate weather conditions of Haiti.

Project Name
Solar Transpired Collector Crop Dryer
Project Number
Start Term
End Term
Faculty Guide
John Kaemmerlen, jxkpdm@rit.edu
Primary Customer
Rob Stevens, rjseme@rit.edu
Sponsor (financial support)
Multidisciplinary Senior Design

Team Members

Kelsey Clements, Kaleigh Sweeney, Matt Hossack, Louis Kline, Catherine Evans

Kelsey Clements, Kaleigh Sweeney, Matt Hossack, Louis Kline, Catherine Evans

Member Role Contact
Catherine Evans Project Manager, Mechanical Engineer cce2302@rit.edu
Kelsey Clements Industrial Engineer kac2903@rit.edu
Kaleigh Sweeney Industrial Engineer kes9107@rit.edu
Matthew Hossack Mechanical Engineer mxh3328@rit.edu
Louie Kline Mechanical Engineer ltk9118@rit.edu

Problem Definition Summary

This phase allowed P17483 to understand and analyze the customer’s requirements for the solar crop dryer. The requirements were each weighted on a 1,3, 9 importance with the most important requirements including dries moderate amount of fruit quickly, low cost materials, keeps drying fruit sanitary, and can withstand environmental conditions. The customer requirements correlate to specific customer and team identified engineering metrics. Some of the most important metrics that relate to and have high weights with the customer requirements include Cost of Materials, Percent of materials in contact with food grade materials, and Time to Dry Fruit. The highest risk factors identified in this stage include air leakage in the designed system, device does not performed as indicated for the end user, and enough heat cannot be generated to dry the fruit. Feedback from the problem definition design review were to include all benchmarking quantities in the same units. Additionally, the subject matter expert encouraged looking into the work of a thesis group at St. Thomas University who conducted similar research.

Systems Definition Summary

During this phase, the design team developed system level designs based on the engineering and customer requirements that were analyzed during the problem definition phase. The team broke the problem down into its basic components using a functional decomposition. From this exercise, it was determined that the controllable functions to focus on were: accept produce, supply air, intake outside air, collect solar energy, transfer moisture, and exhaust moist air. The team used a morphological chart to come up with ideas for each these functions. Combinations of these ideas resulted in four system level concepts that were called: "Tent", "Greenhouse", "Sand", and "Double Chamber." A pugh chart analysis was utilized to compare these ideas to Dr. Steven's model using the engineering requirements as metrics. Based on the analysis, it was found that the "Sand" design is most likely to perform better than Dr. Stevens' existing prototype. The "Sand" model was then proposed to Dr. Stevens in the Systems Design Review. The team was given constructive feedback on certain components of the proposal, and as a result it was decided that the team would revisit their design selection during the next phase.

Preliminary Detailed Design Summary

The activities of the Preliminary Detailed Design Phase (PDDR) included several iterations of MatLab testing on the model developed to gain information about airflow, ending average banana mass, and temperature inside the drying chamber. Various parameters such as the dimensions of the drying chamber, quantity and size of the fruit trays were adjusted to see which parameters produce the best results. A concept was developed to stylize the trays into “packs” or “cubes” that would undergo the drying process together. The concept of drying the test packs in a rotating cycle over two days is tested in the Matlab model. The results of this indicate that rotating the packs lead to approximately equal mass loss over the two day span between the first and second days. A cost analysis was initiated and the bill of materials was itemized with quantities and costs. The initial cost summation was $418 dollars. Following the preliminary detailed design review P17483 is focusing on reducing costs associated with material selection for drying chamber and tray design, redesigning walls to include insulated corrugated metal, and testing of the tray pack concept.

Detailed Design Summary

The Detailed Design Review phase, consisted of furthering activities to put team P17483 in a position to start Multidisciplinary Senior Design 2 productively in spring semester. Furthering our progress towards the tray concept, collector dimensioning, and chimney design, the activities involved modeling and drawing. A large portion of this phase included material planning, BOM requirements, and ordering materials for testing. This phase included assembling sample tray packs that will be used for upcoming tray spacing testing. CAD drawings will be used for machining of parts to perform testing in January. Lastly, MSD 2 weekly agenda and test plans were devised and reviewed by the group.

Build and Test Prep Summary

The team built a prototype drying chamber and did some indoor testing. The prototype chamber was built out of large cardboard boxes and duct tape. The equipment used was located in Dr. Stevens' lab and included a flow meter that allowed P17483 to control the air velocity and temperature. The group completed the test with 2 full tray packs of half inch sliced bananas. So far the comparisons to the Matlab model predictions are encouraging. Preparation work for the collector was also completed. Testing included observing how well the mesh the fruit is placed on performs and how much mass is lost over the one and two day tests.

Subsystem Build and Test

The drying chamber was fabricated and assembled after cutting the appropriate lumber lengths in RIT's Makerspace Construct. During the review of this phase alternate design approaches were discussed (cost vs. durability tradeoffs). Tray assembly has also progressed per plan and the remaining wood for the tray bases was cut to dimension. P17483 thinking through subsystems integration issues for the next phase - e.g. minimizing leakage between subsystems, easing the interaction between the collector and chamber systems

Integrated Subsystem Build and Test

The focus of this phase was in chamber installation and insulation. The entire structure was covered in the corrugated sheet metal. Additionally, the remaining landscaping tarp was used to cover the chimney and the slanted roof. During this phase, the sunny weather permitted for an outdoor collector test, though it was 16 degrees. This provided information on temperature differences and potential airflow expectations. The team is looking forward to the next phase with completion of all construction and beginning full system testing.

Integrated Subsystem Build and Test with Customer Demo

P17483 had an initial meeting with Dr. Steven's to identify the tests he wanted us to perform and specific data to collect. Dr. Stevens offered his help with rigging up extra testing equipment as he was interested in collecting more data for his Matlab model, outside the scope of the project. Challenges faced in this phase were addressing the interface of chamber and collector, as well as the sturdiness of the stand. Completed testing indicated that thicker banana slices are not capable of being dried in the one day timeline in our current Rochester conditions. Completing this testing allowed us to experience the time requirements necessary for a full setup and run.

Customer Handoff & Final Project Documents

A meeting with Dr. Stevens was held on Tuesday May 9th. The results of this meeting were that the team learned what he wanted to be disassembled and sent to Haiti. The result of the meeting indicated which data were important to handover to the customer for the purpose of further fine tuning of the Matlab model. Discussion occurred about discrepancies in the final results and plans were established to make updates and clarifications. Additionally, a meeting is being setup to handover to Sam Husselstein who will do field testing during Summer 2017.

Table of Contents


Planning & Execution

Project Photos and Videos

Imagine RIT

Problem Definition

Systems Design

Preliminary Detailed Design

Detailed Design

Build & Test Prep

Subsystem Build & Test

Integrated System Build & Test

Integrated System Build & Test with Customer Demo

Customer Handoff & Final Project Documentation