Tarp Deployment System for a Produce-Drying House in India

Background

Despite incredible advances in large-scale agriculture made within the last century, sun-drying remains the primary food preservation technique employed in developing nations around the globe. However, sun-drying exposes crops to a number of environmental threats, including degradation by UV exposure and fungal infection. Research has shown that drying chilis in a greenhouse can improve efficiency, boost farmers' profitability, and increase the quality of crops grown.

Project Motivation

UV damage, fungal infection and further damage due to rain and humidity during the monsoon season in India can cause farmers to lose over 10% of their chili crops and 50% of profits on the crops that remain. The Advanced Adaptable Agricultural System (A3S) was developed as a dual drying and growing system that can be used during the drying and growing seasons, thus adding value throughout the year. Although the A3S was able to boost the income of Indian farmers by over 40% in its first year, the current A3S is still expensive and unreliable.

Existing A3S

The A3S has an inner and outer structure. The inner structure uses a telescoping arm, pictured on the left, to roll and unroll a tarp that provides insulation and shading for crops. This system is expensive and unreliable.

Problem Statement & Goal

This project’s objective is to redesign this insulation system to reduce material costs and improve its reliability. The combination of greater affordability and usability will significantly broaden the A3S’s market appeal to smallholder farmers for initial investment, and their long-term commitment to utilize the technology.

High Priority Requirements

The cost of the system should be under $800.
The typical operating motor load should not exceed 75% of its maximum load.
The mechanism should deploy fully 98% over 120 trials.
The total area of air gaps in our system should not exceed the area of air gaps in the current A3S.
Our load estimations should utilize a factor of safety of 2.
The system should be able to stop at a clearance of 4 feet above the ground in the growing season.

Ethical Considerations

Safety: In order to prioritize the safety of the A3S workers, cutting costs should not be at the expense of the safety of the structure.
Food Waste & Quality: Our design should be able to produce high-quality crops, which will contribute to reducing food waste.
Accessibility: Our solution should be as affordable as possible so that the technology can be available to everyone. We should source from manufacturers in India rather than from other countries.
Supply Chain: We want the main profits to go to the farmers themselves, but we have limited control over how profits are distributed within the supply chain.

Our Solution

We abandoned the inner steel structure and replaced it with two sets of cables that support the two inner tarps. We installed grommets in the tarp, and we use hooks to hang the tarp from the cable. The cables attach to the nodes of trusses at the ends of the outer structure, and turnbuckles are used to adjust the sag and tension in the cable. A winch mechanism retracts and deploys the tarp.

Working Hardware

Our latest prototype is pictured to the left. We built this prototype at the O'Donohue Farm.

Results from Testing Tension in Cables

Our results show that our calculations predict the tension in the cable accurately. This allows us to confidently make predictions about the tension in the cables that will be used in the real A3S, thus ensuring the safety of the system.

Cable Tension Test Data

Team Jookali

Sharon Perez

Financial Officer

Engineering Analysis Lead

Jason Torres

Liaison Interface

Builder

Sidney Stevens

Project Manager

P3D Maker

Gallery

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