Team Solar Fig Dehydrator XE: 388 Fall 2011 "The Figtastic Four"

Team Solar Fig DehydratorXE: 388 Fall 2011"The Figtastic Four" Mati AyanaStephen MarchDustin McLeanDavid Mindham

Project Background Purkal Youth Development Society (PYDS) 3rd project year Overall project: Develop a fig dehydrator Why: • Short Shelf life (7-10 days) • Easy to Bruise • Transportation of figs is difficult Our Part: • Perform data analysis on the designed and created unit from previous groups • Use our findings to implement design changes to improve the overall efficiency of the dryer

Scope and Objectives Develop understanding of previous groups’ work Collect data to assess the capabilities of the dehydrator Analyze the collected data Determine any needed design modifications based on data analysis Prepare design modifications for next group to implement Develop economic analysis for dehydrator use Construct outline for future group(s) to finish the project

Data Collection and Analysis Used other fruits than figs Daily data collection • Before temperature probe • After temperature probe Results showed temperature dependency on: • Ambient air temperatures • Wind Speed • Solar Intensity • Thickness of Fruit slices

Start of Day End of Day Before and After Comparison

Ideal Conditions Profile 20 October 2011

Profile Comparison

Solar Intensity- All days

Wind Speed

Temperature Probe Data

Design Change 1: Aluminum Foil Old design shortfalls: • Oven took long time to reach high heat level • Hot air not dispersed evenly • Need higher oven temperatures on slightly cooler days Acts as Heat sink • Pulls hot air into oven • Evenly disperses hot air throughout oven • May not be needed in warmer climate Adds approximately $1.00 to the cost of the dehydrator. Implemented 10/10/11

Design Change 2: Circuit Changes Shortfalls of old design: • Wastes power when not running • Fan draws more power than needed • Large battery is expensive Proposed changes: • Decrease Battery from 33 Amp-hr to 3 Amp-hr • Install switch to turn machine off when not in use • Install resistor to reduce fan's power consumption

Design Change 2: Circuit Changes

Design Change 2: Circuit Changes Advantages of Changes: • Lower power consumption means smaller and cheaper battery • Turning circuit off leads to longer circuit life. • More control over when fans run. • Reduces cost of machine by $40.00. • Smaller battery has less environmental impact Design Alternatives: • Batteries from 3-33 Amp-hr considered. • Photo transistor vs. physical switch • Resistor vs. no resistor

Design Change 3: 2nd Plastic Cover Old Design: • One plastic cover for sun hitting area • Not adequate to prevent heat loss

Design Change 3: 2nd Plastic Cover New Design: • Additional plastic cover for sun hitting area • Potentially adequate to prevent heat loss

Design Change 3: 2nd Plastic Cover Plastic cover Benefits: • Locally available • Easily replaced • Inexpensive • Little waste • Gives additional cover preventing heat loss Plastic cover Cost: • Adds a small amount of cost ($14.26) • Must be periodically changed • Benefits not fully determined

Cost Predictions Cost Comparison: • The 2011 price design only 88% of 2010 design • Payback period longer, last group used questionable data.

For the Next Group(s) • Report outlines process for next groups • Challenges to expect

Questions?

Team Solar Fig Dehydrator XE: 388 Fall 2011 "The Figtastic Four"