We continue to develop resources related to the COVID-19 pandemic. See COVID-19 initiatives on Appropedia for more information.

Locally Delicious school solar dehydrator

From Appropedia
Jump to navigation Jump to search

Abstract

Background

Locally Delicious is a group of women collaborating on a new book titled "Lunch Box Envy." Several different Engineering 215 projects are to be included. The School solar dehydrator is one of them. Locally Delicious

Team Member Pages: Alisha Sughroue Mary Wooldridge Justin Thompson James Courtney

Objective and Criteria

Criteria Weight Description
Safety 10 This is defined as a structure being stable enough for children, having safe building materials for food quality, and having a completely finished project to protect children against loose material or sharp edges.
Cost 9 Design must cost less than $300.
Reproducible 9 This is defined as the ease of following the directions and constructing the solar dehydrator.
Durability 8 This is defined as having a structure that is able to last two to three years with regular use by adults and children.
Weather Resistance 8 This is defined as the structure’s ability to hold up against all types of weather.
Ease of Use 7 This is defined as a structure that has a design that is easily operated on a child’s level.
Efficiency 7 This is defined as the project's ability to dry food quickly and to dry the food to the operator’s expectations of good quality dehydration.
Aesthetics 4 This is defined as the project with a presentable and school appropriate design.

Description of Final Project

This project was to design a solar food dehydrator to be replicated by schools.

Sunlight enters the slanted solar collector through the glazing, a polycarbonate sheet, and heats up a metal sheet. The air between the glazing and the solar collector warms, which causes it to become less dense and rise. As this air rises, it is replaced by outside air entering from the bottom of the collector which is then heated as well. The rising air eventually exits the collector and enters an insulated elevated cabinet with an air vent on the top. Since the air inside the cabinet is less dense than the outside air from being heated, it moves vertically within the cabinet and exits the cabinet through the vent. The cabinet contains horizontally oriented frames with nylon mesh in which produce is placed on. This produce dries from the moving hot air it is exposed to.

The solar collector contains a black painted copper sheet which sits on top of insulation within a polycarbonate covered wood box.

Costs

Table 2. Itemized Cost of Materials
Materials Use Quantity Project Cost ($) Projected Cost ($)
Small Cabinet Dryer Box 1 6.00 40.00
Screen Covering End of Solar Collector 1 1.00 4.00
Styrofoam Insulation Insulation of Solar Collector 4 1.50 60.00
Copper Sheet Metal Heat Conductor for Solar Collector 63" X 27" 40.00 40.00
Metal Roof Roofing for Weather Protection .97 tons 5.00 12.00
Insulation Insulation for Dryer Box 5'X 4' 22.82 22.82
Polycarbonate and Fitting Screws Glazing Material 10' X 26" 45.89 45.89
Screws, Sealant,Latch, and Polyfoam Putting together Solar Collector Glazing N/A 30.91 30.91
Tacks Securing Insulation 1 box 1.34 1.34
Caulking Not used 1 tube 5.84 0.00
Hinges For Cabinet Doors(not used) 2 packs 9.88 0.00
Hinges and Piping Cabinet Doors and Connecting Solar Collector N/A 9.27 9.27
Nylon Mesh Drying Racks 3 yards 6.08 6.08
All Lumber Collector Box, Drying Racks, and Base N/A 0.00 33.00
Polyvert Closure Set Glazing on top of 6 5.99 5.99
Paint Whole project 1 can 31.00 31.00
Total 222.52 265.31

Testing Results

How to Build

Next Steps

References