Spring Design Package

Problem Statement

Poverty, food scarcity, and foodborne illnesses due to improper storage of food are major problems facing developing countries. The average farmer cannot afford current grain drying equipment—instead resorting to inefficient methods such as roadside drying. A more efficient drying method would increase the amount of grain available for storage by preventing spoilage and contamination. Our goal is to design and build an affordable (<$200), more efficient grain dryer using local materials that utilizes a passive method, such as solar or wind energy, to dry the grain.

Executive Summary

A typical Nigerian farmer produces 240 bushels of corn and stores approximately 60% (144 bushels) of their harvest (Adedeji, 2018). Harvesting is done in batches of approximately 8 bushels, effectively spreading the 144 bushels to be dried over a period of 18 days (McNeill, 2018). A bushel of corn is assumed to be 60 ears at 7” X 2” diameter (Showalter, 1964). The moisture content of freshly harvested corn is approximately 25% and must be reduced to 14% for proper storage (University of Nebraska-Lincoln, 2016). Current drying methods lead to unnecessary post-harvest losses of grain due to spoilage from slow drying times and contamination (Adedeji, 2018).

Our design is an indirect-type active solar energy dryer. It includes a drying chamber, solar collector, 410 CFM fan, and a 50 W solar panel. Under ideal conditions, our design is expected to dry 8 bushels per 17.5 hours of sunlight. This rate will reduce grain losses due to spoilage while the enclosed design will reduce environmental contamination.

Our total costs for materials of the grain drying system is $437.48. This is inflated due to our having to purchase all necessary items out of pocket. While this value is higher than the $200 limit set by the customer, faculty members familiar with grain drying in Nigeria note that the typical Nigerian farmer will use leftover and salvaged materials to obtain a cost of $200 or less (McNeill, 2018).

Drying Chamber

    • Capacity: 8 Bushels
    • Moisture Removed: 71.6lbs (University of Nebraska-Lincoln) (Flycarpet Inc.) (Henderson) (Marshal)
    • Size: 4’X5’X6.5’
    • Volume of Chamber: 60ft3
    • Details: Four doors, angled roof for air flow, and four chicken wire shelves placed 6” apart. The cobs are placed 1/2in apart.

Solar Collector

    • Volume Required: 5117 m3 D.A. (Flycarpet Inc.) (Henderson) (Marshal)
    • Velocity: 410 CFM
    • Temperature and Relative Humidity Entering Collector: 25℃, 85% (TuTiempo)
    • Temperature and Relative Humidity Entering Chamber: 52℃, 63% (Flycarpet Inc.) (Henderson) (Marshal)
    • Temperature and Relative Humidity Exiting Chamber: 36℃ 61.4% (Flycarpet Inc.) (Henderson) (Marshal)
    • Size: 3’X6’X 4.75”
    • Details: Wood frame, 1” thick cardboard insulation, scrap metal, and greenhouse film

Expected Drying Time: 17.5 hours

Wiring Diagram

Bill of Materials

Updated Bill of Materials

References

Adedeji, Akinbode - Client Meeting [Personal interview]. (2018, September 19).

Chua, K., & Chou, S. (2003). Low-cost drying methods for developing countries. Trends in Food Science & Technology, 14(12), 519-528. doi:10.1016/j.tifs.2003.07.003

Elmore, R., & Abendroth, L. (2007, September). How fast can corn dry down? Retrieved October, 2018, from https://crops.extension.iastate.edu/how-fast-can-corn-dry-down

Evans, K. (2018, October 24). Corn Drying and Quantity [Personal interview].

FlyCarpet Inc. (2018). Accessed on October 25, 2018 from www.flycarpet.net/en/psyonline.

Food and Agriculture Organization of the United States. (1994). Grain Storage Techniques. (D. Proctor, Ed.) Rome: Food and Agriculture Organization of the United States. Retrieved

September 26, 2018, from http://www.fao.org/docrep/t1838e/T1838E0v.htm

Growing Maize in Nigeria. Commercial Crop Production Guide Series. Retrieved September 19, 2018, from http://biblio.iita.org/documents/U03ManIitaMaizeNothomNodev.pdf-43dafa4ce4033f16250975d3b036c570.pdf

Hanbin, W. (n.d.). Research and development issues in grain postharvest problems in Asia - Overview of grain drying in China - Some imperatives in crop drying research. Retrieved September 19, 2018, from http://www.fao.org/wairdocs/x5002e/X5002e03.HTM

Henderson, S. M., Perry, R. L., Young, J. H. (1997). Principles of Process Engineering. American Society of Agricultural Engineers.

How to Figure the Correct Angle for Solar Panels. (n.d.). Retrieved from https://www.solarpoweristhefuture.com/how-to-figure-correct-angle-for-solar-panels.shtml

Jain, K. (2012). Introduction - Solar Drying Of Food Products. Retrieved September, 2018, from https://sites.google.com/site/solardryingmodelling/project-overview-1

Marshall, J. L., Williams, P., Rheault, J., Prochaska, T., Allen, R. D., DePoy, D. L. Characterization of the reflectivity of various black materials. Department of Physics and Astronomy Texas A&M University.

McNeill, S. (2018, November 6). Grain Drying in Nigeria [Personal interview].

Peace Corps. (n.d.). Improved Food Drying and Storage: A Training Manual. Retrieved September 26, 2018, from http://www.nzdl.org/gsdlmod?e=d-00000-00---off-0hdl--00-0----0-10-0---0---0direct-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0--4----0-0-11-10-0utfZz-8-10&cl=CL1.9&d=HASHc885af8bb1b48c971da66d.6.3&x=1

Showalter, R. K. (1964). Ear size and weight characteristics of Florida sweet corn. Florida State Horticulture Society.

TuTiempo. (2018). Abuja Climate data: 1994 – 2018. Retrieved on September 20, 2018, from https://en.tutiempo.net/climate/ws-651250.html

University of Nebraska-Lincoln. (2016, March 10). Harvesting, Drying, Storing Late-Maturing, High-Moisture Corn. Retrieved October 24, 2018, from https://cropwatch.unl.edu/harvesting-drying-storing-late-maturing-high-moisture-corn

Varun, Sunil, Sharma, A., & Sharma, N. (2012). Construction and Performance Analysis of an Indirect Solar Dryer Integrated with Solar Air Heater. Procedia Engineering,38, 3260-3269. doi:10.1016/j.proeng.2012.06.377

Visavale, Ganesh. (2012). Principles, Classification and Selection of Solar Dryers. 1-50.