1. Detailed Design Review
Solar Transpired Collector Crop Dryer
P17483
December 8, 2016

2. Team Introductions Team Member Major Role Caly Evans
Mechanical Engineering
Project Manager
Matt Hossack
Louie Kline
Kaleigh Sweeney
Industrial Engineering
Kelsey Clements
Caly

3. Agenda Current Problem CRs and ERs Designed Components
Trays
Drying Chamber
Solar Collector
Chimney
Proposed Bill of Materials
Testing Plan
Limiting Operator Error
Risk Assessment
MSD II Plan
Schedule, Design, Test Plans,

4. Problem Statement Current State Desired State Project Goals
Previous designs developed which are functional but not suitable for construction in Haiti
Desired State
A robust prototype made of area-appropriate materials, capable of drying moderate amounts of fruit in a few days
Project Goals
Analyze current designs
Identify opportunities to:
Increase temperature
Increase airflow
Constraints
Materials must be available in Haiti
Food safety
Budget
Kelsey

5. Customer Requirements

6. Engineering Requirements
Rqmt. #
Engineering Requirement (Metric)
Unit of Measure
Ideal
Minimum
In Design
ER 1
Moisture content of fruit
Weight %
<10
<15
15%
ER 2
Quantity of dried fruit
Kilograms/Day
>10
>5 8
ER 3
Percent of materials in contact with food that are food grade
% of Surface Area in Contact with Food
100
100%
ER 4
Fruit meets food and safety specifications
Bacteria/Sq. inch *
In progress
ER 5
Time to dry fruit
Hours
<24
17 hours
ER 6
Payback time
Months
<12
ER 7
Cost of materials
Dollars
<50
<100
ER 8
Tools required for assembly/disassembly
# of Tools
1-3
In design
ER 9
Reading level for instructions
Reading Level #
No reading required
<2
N/A

7. Engineering Requirements
Rqmt. #
Engineering Requirement (Metric)
Unit of Measure
Ideal
Minimum
In Design
ER 10
Time for disassembly
Minutes
<45
<90
N/A
ER 11
Number of imported materials
# materials
0-1
<5 2
ER 12
Footprint size
Ft x ft x ft
<9x5x4
8 x 4 x 3
ER 13
Time spent attending to the device during operation
<10
ER 14
Number of steps to initiate drying steps
# of Steps
TBD
ER 15
Part replacement rate
Parts/month
1-2
ER 16
General maintenance frequency
Times/week
<3
ER 17
Withstand high wind speeds
Wind speed mph
>45
>30
ER 18
Water drainage time
<1

8. Tray Concept 6 packs of 6 stacked trays Full frame on bottom tray
Parallel side pieces on trays 2-6
Square for alternating directions.

9. Tray Concept Continued
Base tray

11. Chamber Size 16” tray 20” tray 0.035 mair ave. [kg/s] 0.044 20.0
ΔT [C]
19.2
5.94
Mass remov. [kg]
6.77
(Same total mass of bananas split between trays.)
21” x 63” internal chamber size
(16” sq trays)
25” x 75” internal chamber size
(20” sq trays)

12. Insulation Calculations - Straw/Grass
Thermal resistance of tarp and corrugate metal were negligible.
Thermal loss calculated using predicted temperature increase.
Wall diagram:

13. Drying Chamber
Door Side

14. Drying Chamber - Front View

15. Drying Chamber - Bottom View

16. Drying Chamber - Right Side View

17. Collector Size
8 ft
4 ft 3 in

18. Collector Size Justification
Energy required to remove necessary water.
Average necessary mass removal rate, over 2 days
Dryer efficiency, based on average mass flow rates.
Promising value, as Dr. Steven’s dryer ran around 55-60% efficiency

19. Collector Size Justification
Energy required accounting for drying chamber efficiency.
Estimate collector efficiency, calculated collector area needed for energy absorption.
Our collector, approximately 72% greater area.

20. Collector Matlab Results
6’x6’
8’x8’
0.024
mair ave.
[kg/s]
0.044
19.4
ΔT [C]
19.2
4.34
Mass remov. [kg]
6.77
~ 6’ x 6’ collector
~ 8’ x 8’ collector

21. Chimney
The chimney will run the entire length of the drying chamber, approximately 75” long.
Vent locations
Matlab simulations were performed on widths from 2” to 12”
< 6”, air flow rates (and performance) dropped
> 6”, little to no change, will not make it larger because we would need more roof material.
Additional solar heating was added to the model, which increased air flow nearly 50%
~ .05 kg/s to ~ .08 kg/s

22. Non-Heated Chimney vs Heated
Small rect. duct, no heat
6”x75” 12” h, w/ heat
0.044
mair ave.
[kg/s]
0.076
19.2
ΔT [C]
16.8
6.77
Mass remov. [kg]
7.64

23. Final Proposed Design

24. Bill of Materials Team Haiti
We want to try other materials for the back of the collector because plywood is very expensive in Haiti
Last review our material cost was over $415

25. Test Plan Description Planned Date Intended Result ERs Addressed 1
Test the tray packs inside the cardboard enclosure
MSD II, week 1
To know the best tray spacing and location within the drying chamber
moisture content of fruit 2
Test the differences between doing 4 pack and 6 pack.
evaluate drying based on fruit spacing on trays 3
Dryer/chimney assembly, indoor with simulated environment
MSD II, weeks 5-6
Preliminary evaluation of drying capability of full system.
moisture content, time to dry fruit, human-device interaction during operation, number of steps to initiate drying 4
Full system assembly, with collector, ideally outdoor
MSD II, weeks 8-11
evaluate full system, with mass removal, air flow, temperature and humidity measurements 5
Weather testing (water resistance)
Evaluation of reasonable rain resistance of system, add weatherproofing as needed.
water resistance and drainage, general maintenance 6
Assembly test with volunteers
MSD II, week 12
Finalize assembly and operation instructions
Reading level of instructions, tools required

26. Limiting Operator Error
Uniform thickness of fruit slices:
We will be making our own banana slicers (wood frame with wire strung through holes) to slice entire fruit at once.
We also plan to put thickness indicators on the side of the drying chamber.
Tray Assembly:
The square base allows users to put the mesh trays on any direction, although directions will be provided for the preferred orientations.
Picture/photo-based instructions.

27. Risk Assessment 9 9

28. MSD II
Plan