Solar Powered Attic Fan Brent Houghton Dominic Gayle Alejandro
Osorio Faculty Advisor: Dr. Seyad Ebrahim Beladi
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Household Attic Temperatures in attics can reach up to 140
Degrees Fahrenheit Infiltrations/Air leakage into household Results
in increased strain on A/C
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Turbines and Fans Visually Unappealing Provide Little
Ventilation Power Consumption
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Current Market Weaknesses Most current models do not implement
a rechargeable battery. Under powered and overestimated in terms of
performance. Geographic orientation on roof is confined to solar
angles.
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General Design
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Major Components 4 X Sunforce 50022 5 Watt Trickle Charger
configured in parallel Current: 325 mAmps @ 15 V Diode to prevent
reverse discharge from battery
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Pulse Width Modulator to govern RPMs An pulse width modulator,
or PWM, is an electronic circuit which is primarily used to vary an
electric motor's rotational speed and direction it may serve as a
dynamic brake as well. ESCs are often used on electrically powered
radio controlled models, with the variety most often used for
brushless motors essentially providing an electronically-generated
three phase electric power low voltage source of energy for the
motor. trol. trol
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Sunforce 7 Amp Solar Charge Controller Protects battery from
overcharge/discharge. Handles up to 7 Amps of array current.
Maintains 12 Volt battery in a fully charged state.
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Powersonic PS-12350-NB Deep Cycle Battery 12 Volt/35 Amp Hour
Sealed Lead Acid Battery Deep Cycle Battery intended for high
charge/discharge rate. Wide operating temperatures ideal for attic
conditions. Valve regulated, spill proof construction allows for
safe operation in any position.
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Procomp 14 Pusher/Puller Fan 12 Volt DC high performance
reversible electric cooling fan. Blades and wire polarity may be
reversed for pushing/pulling option. 2000 CFM rating.
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GadgetZone CN101 Digital Programmable Timer Programmable for 17
ON/OFF events per day. Dual installation allows for air
outake/intake. Lithium battery to prevent short during power
outage.
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Fundamental Design 4 solar panels charge battery daily. Allows
for continuous usage during night and day. CFM/s may be adjusted
due to power budget.
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Fundamental Design: Housing Structure
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Fundamental Design: Automatic Control Panel
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Potential Problems To generate enough current to sufficiently
charge battery to power motor driven fan? Heat from attic can be a
strain on battery Higher cost than conventional solar fans, yet
more advanced Sleek design with regard to marketing
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Literature Survey Attic Fans. Solar powered attic fans.
Photovoltaic Cells
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Attic Fans Used in warmer and cold climates. Summer months
temperature can reach 160 F. Moisture and cold can lead to mildew
growth in the attic as well on winter season.
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http://www.bluepointenvironmental.com/
wp-content/uploads/2012/01/attic- contamination1.jpg
http://www.ussunlight.com/images /product_images/products_general/
winter_apv.jpg Moisture on Attics
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http://poweredbydaylight.com/wp-
content/uploads/2011/03/attic-heat-300x300.jpg Summer Season on
Attics
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Solar Attic Fans Solar attic fans are available for general
consumer on retail stores. No efficient product limited to a power
delivered for a photovoltaic cell. Generally Solar Attic are not
very aesthetically pleasing to homeowners.
Environmental Impacts Most components pose no threat. Battery
is rechargeable. Runs on direct current. Ideal for any suitable
geographical locations In which a need arises.
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Generate large amounts of electricity without producing any
pollution to the ambient surroundings or adding to global warming.
Photovoltaic cells can have working lives of up to 30 years
Manufacturing companies must employ proper protocols to prevent
exposure of these chemicals to the environment.
http://grist.files.wordpress.com/2013/04/s olar-panels-homepage.jpg
http://www.think-solar-power.com/Photovoltaic-
Solar-Power.html
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http://www.dbpow.com/ http://www.sunforceproducts.com / Low
impact to the ambient on manufacturing process. Optimize equipment
use and extend operation hours.
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POWER SONIC 96% of all lead-acid batteries are recycled. Almost
any retailer collects used batteries for recycling (State laws)
They send the plastic to a reprocessor for manufacture into new
plastic products. lead-acid battery contains 60 to 80 percent
recycled lead and plastic.
http://www.batteryweb.com/power-sonic-corporation.cfm
http://ecobatgroup.com/ecobat/rp/
http://www.batteryweb.com/power-sonic-corporation.cfmhttp://ecobatgroup.com/ecobat/rp/
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.http://thumbs2.ebaystatic.com/d/l225/m/mQzgm6
y2pubd8L75antwOYg.jpg http://blog.heliumware.com/wp-
content/uploads/2011/01/IMG_0111.jpg Housing, blades and mounting
brackets are made from plastic. Cooper coil winding. Indirectly
Powered by Solar Energy.
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ASHRAE American Society of Heating, Refrigerating, and
Air-Conditioning Engineers. ASCE American Society of Civil
Engineers. ASM - American Society for Metals. (6061) ASME -
American Society for Mechanical Engineers. IEEE - Institute of
Electrical and Electronics Engineers. ANSI American National
Standards Institute.
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Tropical storms and hurricanes are devastating and as such
steps must be considered in design.
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CategoryWind Speed (m/s)Wind Loading (N) Wind Loading (lbf)
Storm3216537 14228564 24938887 358544122 470792178 Wind Loading =
0.5 v 2 C d A C d ranges from 1.2 - 1.65. Use 1.65 for safety.
Analysis conducted as if force acted perpendicularly to
housing.
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Initial model used to conduct analysis. Due to software
limitations, certain concessions were necessary.
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Greatest stresses were concentrated in the bends of the
housing. Safety factor of 1.2 under tropical storm loading.
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49 MPa maximum stresses within the bended regions. Safety
factor of less than 1.
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Recommended fastener : #8 X 2 screw, self-tapping and
galvanized ASTM standard. Length will vary depending on roof
thickness. 650 screws for $34.55.
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Housing failure more significant than fasteners. Poor
aerodynamic structure results in tremendous wind loading. Remove
attic fan for conditions greater than tropical storm loading.
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Simulation conducted with hemispherical dome. Diminished area
results in max velocity of 4.4 m/s (13 fps).
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Highest pressure experienced around outlet regions of
housing.
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Slide 39
Outdoor Temperature (F) Indoor Temperature (F) Attic
Temperature Before Activation Cycles (F) Attic Temperature After
Activation Cycles (F) Attic Temperature Difference (F)
8578.0106.392.413.9 8279.1102.585.616.9 8578.0107.992.415.5 Based
on fan drawing 1.8 Amps @ 600 CFM for 90 second interval (expulsion
cycle). Resting interval for 60 seconds (no fan activity). Based on
fan drawing 1.8 Amps @ 200 CFM for 60 second interval (intake
cycle).
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Estimate of 4.31 kWh/day savings. Investigate a real-world
global issue and use engineering knowledge to address it. Gain
valuable experience and insight into manufacturing process.
Importance of team work i.e. goal specifications, task delegation,
conflict resolution,etc.
