Transcript Poster - Solar Energy at SDSU

Parabolic Solar Water Distillation
TEAM MEMBERS
Joel Newmeyer Mark Branner Andrew Stonebraker
Motivation
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Overall Goal
About 1 billion people do not have access to potable
water
Make use of the most abundant naturally replenished
energy source
Parabolic reflective troughs are fundamentally simple
and effective devices for concentrating and collecting
solar energy

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Efficiently supply at least 2 gallons of potable water per day
Create a product that will be relatively easy to establish and operate
Purify water from any source
Inexpensive
Provide clean useful drinking water without interfacing with electricity
Determining Distiller Geometry
•
•
2.5 ft2 base cross section
0.75 ft high condensing surface
2.50E+03
200
199.5
199
198.5
198
197.5
197
W
2.00E+03
average heat
transfer, W
1.50E+03
conv heat transfer,
W
1.00E+03
0.00E+00
0.031
0.181
0.453
0.849
1.368
2.010
2.775
3.663
4.674
5.809
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
5.00E+02
60
W/m
Average Useful Gain per Meter
Tsat=100C, Aperture area=8 m^2, Receiver Area=25 in^2,
Average daily radiation=338W
estimated mean fluid temp, C, (Tin+Tsat)/2
distiller cross section area, ft^2
4.
5.
0.031
0.126
0.283
0.502
0.785
1.131
1.539
2.010
2.544
3.140
3.800
4.522
5.307
6.155
gph
1.00E+00
8.00E-01
6.00E-01
4.00E-01
2.00E-01
0.00E+00
distiller cross section area, ft^2
Average Condensation Rate
8.00E-01
6.00E-01
4.00E-01
2.00E-01
0.00E+00
0.164
0.230
0.295
0.361
0.426
0.492
0.558
0.623
0.689
0.754
0.820
0.886
0.951
1.017
1.082
1.148
1.214
1.279
3.
Contaminated water enters an absorber tube (Pyrex glass
cover, copper heat pipe) oriented at the focus of a parabolic
reflective trough.
Heated water exits absorber tube and enters distiller via spray
nozzle to increase surface area per droplet to enhance
evaporation.
Remaining hot water pools and distiller then allows for further
evaporation.
Vapor is condensed on a cooled condensing surface via heat
exchanger oriented on the top of the distiller
1.
Heat exchanger uses cool contaminated water flow to
cool the condensing surface and preheat the incoming
water
Condensed potable water drains out of distiller via gravity into
a collection tube
gph
2.
Distiller Sectional View
Assembly
Front view
Distiller inlets/outlets
average heat
transfer, W
Average Mass Flux from Water Pool in
Distiller
System Overview
1.
heat transferred
by evap, W
cone condensing surface height, ft
Right view
Conclusion
After a semester of research and calculations, we have settled on a final design of
a solar still, a solar still that will maximize potable water production. Some of our
future project goals include:
•
Refinement and consistency improvements.
• i.e. getting a constant film flow of water down the coned heat
transfer surface.
• Spray nozzle at heat exchanger inlet.
• Fabric material or grooves to distribute the water over
the surface.
•
Fabrication and assembly of our design.
•
Prototype testing/data acquisition.
Acknowledgements
Sponsor: Akasha Kaur Khalsa
Advisor: Dr. Fletcher Miller
Special Thanks: Dr. Kee Moon