U.S. patent application number 12/662831 was filed with the patent office on 2011-09-08 for solar-powered soffit fan.
Invention is credited to Peter L. Randall.
Application Number | 20110217194 12/662831 |
Document ID | / |
Family ID | 44531494 |
Filed Date | 2011-09-08 |
United States Patent
Application |
20110217194 |
Kind Code |
A1 |
Randall; Peter L. |
September 8, 2011 |
Solar-powered soffit fan
Abstract
The solar powered soffit fan includes an electric fan mounted
over a soffit vent. A roof-mounted photovoltaic solar panel aimed
at the sun delivers power to the soffit fan. During daylight hours,
the photovoltaic solar panel provides sufficient electrical power
to activate the soffit fan, which provides forced attic ventilation
through the soffit vent. At night, the fan automatically powers
down when sunlight no longer impinges the solar panel. A thermostat
and/or humistat can be included for additional control of the unit.
The fan can accept power from an optional rechargeable battery.
Multiple soffit fans can be configured to service larger
buildings.
Inventors: |
Randall; Peter L.; (Davie,
FL) |
Family ID: |
44531494 |
Appl. No.: |
12/662831 |
Filed: |
May 5, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61282604 |
Mar 5, 2010 |
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Current U.S.
Class: |
417/423.14 ;
454/239; 454/251; 454/365 |
Current CPC
Class: |
F24F 11/76 20180101;
F24F 7/04 20130101; F04D 25/06 20130101; F24F 7/02 20130101; F24F
7/06 20130101 |
Class at
Publication: |
417/423.14 ;
454/365; 454/239; 454/251 |
International
Class: |
F04D 25/06 20060101
F04D025/06; F24F 7/02 20060101 F24F007/02; F24F 11/053 20060101
F24F011/053; F24F 7/06 20060101 F24F007/06; F24F 7/04 20060101
F24F007/04 |
Claims
1. A solar-powered soffit fan, comprising: at least one exterior
soffit fan and housing therefor adapted for mounting over a clear
airflow opening in a soffit of a building structure; a solar
photovoltaic panel adapted for mounting on the building structure
proximate the fan; an electrical power cable electrically
connecting the solar photovoltaic panel to the soffit fan; and a
protective screen attached to the soffit fan housing over an
intake-exhaust portion of the soffit fan housing.
2. The solar-powered soffit fan according to claim 1, wherein said
at least one soffit fan comprises a plurality of fans electrically
connected to each other, the fans being disposed in a single
housing.
3. The solar-powered soffit fan according to claim 1, further
comprising a semi-rigid flexible duct connected to said soffit fan
housing, the duct directing airflow between the soffit fan assembly
and the building structure's attic portion.
4. The solar-powered soffit fan according to claim 1, further
comprising a thermostat electrically connected to said
solar-powered soffit fan, the thermostat controlling start, run,
and stop cycles of said soffit fan according to a preset desired
temperature.
5. The solar-powered soffit fan according to claim 1, further
comprising a humistat electrically connected to said solar-powered
soffit fan, the humistat controlling start, run, and stop cycles of
said soffit fan according to a preset desired humidity.
6. The solar-powered soffit fan according to claim 1, wherein said
at least one soffit fan is configured for drawing cool, ambient
outside air from below the soffit into the building structure's
attic.
7. The solar-powered soffit fan according to claim 1, wherein said
at least one soffit fan is configured exhausting hot air from the
building structure's attic out to the exterior of the building
through the soffit opening.
8. The solar-powered soffit fan according to claim 1, wherein said
at least one soffit fan comprises a first soffit fan configured to
blow cool outside air into the building structure's attic and a
second soffit fan configured to simultaneously exhaust hot air from
the buildings structure's attic to the exterior of the building,
thereby creating a push-pull airflow effect.
9. The solar-powered soffit fan according to claim 1, wherein the
solar photovoltaic panel mounting has tilt adjustable members
allowing said solar photovoltaic panel to be tilted toward the
sun.
8. The solar-powered soffit fan according to claim 1, further
comprising: a battery operably connected to said solar-powered
soffit fan; a charge control device electrically connected to said
solar panel and to the battery, said charge control device
selectively using electricity from said solar panel to charge the
battery, the battery being configured to power said soffit fan when
there is insufficient sunlight to energize said solar panel.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/282,604, filed Mar. 5, 2010.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to building attic ventilation,
and more specifically to an easily installed solar-powered soffit
fan.
[0004] 2. Description of the Related Art
[0005] Buildings usually incorporate ventilation systems in their
attics to limit the adverse effects of heat and humidity build-ups
in said spaces. The air in an attic is heated by solar energy
through the roof and related supporting exterior structure. During
night, roofs radiate heat and cool to ambient air temperature.
This, in turn, cools and condenses air below the roof in attics.
The air becomes more humid, and surface dampness can result. When
the sun rises, it starts to heat the roof and facing structure,
which in turn heats the air space in the attic.
[0006] The transfer of heat from the attic air to the adjacent
living areas adjacent to the attic is directly proportional to the
temperature difference between the attic air and the air in the
adjacent living areas. As the air temperature in the attic rises
due to solar energy, the air temperature in enclosed living spaces
usually rises, requiring additional room ventilation, and/or air
conditioning to maintain acceptable living and storage
temperatures.
[0007] In an attempt to overcome excess humidity in attic crawl
spaces, builders have installed passive soffit-mounted vents, which
allow the air in an attic to circulate out through the vents.
Passive ventilation works in ideal ambient conditions, however may
not be effective on windless days when the ambient air is hot,
humid, and stagnant.
[0008] A soffit-mounted fan would solve the problem. However,
traditional soffit fans require running an electrical cable from
the building circuit box to the unit. A unit having an independent
power source would be highly desirable.
[0009] Thus, a solar powered soffit fan solving the aforementioned
problems is desired.
SUMMARY OF THE INVENTION
[0010] The solar-powered soffit fan includes an electric fan that
is mounted over a soffit vent. A roof-mounted photovoltaic solar
panel aimed at the sun delivers power to the soffit fan. During
daylight hours the photovoltaic solar panel provides sufficient
electrical power to activate the soffit fan, which provides forced
attic ventilation through the soffit vent. At night, the fan
automatically powers down when sunlight no longer impinges the
solar panel. Mounting the fan over the soffit vent obviates the
necessity of attic entry, roof access, and the like. Use of the
roof-mounted solar panel obviates the necessity of running
electrical power conductors from an external source, such as an
electrical power panel. A thermostat and/or humistat can be
included for additional control of the unit. The fan can accept
power from an optional rechargeable battery. Multiple soffit fans
can be configured to service larger buildings.
[0011] These and other features of the present invention will
become readily apparent upon further review of the following
specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is an environmental, perspective view of a
solar-powered soffit fan according to the present invention, shown
with portions of the building omitted or broken away to show
details thereof.
[0013] FIG. 2 is a partially exploded environmental, perspective
view of the solar-powered soffit fan according to the present
invention.
[0014] FIG. 3 is a perspective view of the fan of FIGS. 1 and
2.
[0015] FIG. 4 is a partial environmental perspective view showing
an exemplary solar panel installation for a solar-powered soffit
fan according to the present invention.
[0016] FIG. 5 is a partial environmental perspective view of a
solar-powered soffit fan according to the present invention,
showing an exemplary method of connecting the fan to the solar
panel.
[0017] FIG. 6 is a block diagram showing exemplary components of a
solar-powered soffit fan according to the present invention.
[0018] FIG. 7 is a perspective view of an alternative embodiment of
a solar-powered soffit fan according to the present invention,
showing a housing for three soffit fans.
[0019] FIG. 8 is a partially exploded, environmental perspective
view of the solar-powered soffit fan of FIG. 7.
[0020] Similar reference characters denote corresponding features
consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] As shown in FIGS. 1, 2, 4 and 6, the solar-powered soffit
fan, designated generally as 10 in the drawings, includes an
electric fan 20 which can be surface, flush or insert mounted over
a soffit vent 11 that has free air access to the attic 12 of a
house H or other type of building. At least one photovoltaic solar
panel 25 mounted on the building structure, e.g., roof-mounted, and
aimed at the sun delivers power via a power cable 40 to the soffit
fan 20. During daylight hours the photovoltaic solar panel 25
provides sufficient electrical power to activate the soffit fan 20,
which provides forced attic ventilation through the soffit vent 11.
At night the fan 20 automatically powers down when sunlight no
longer impinges the solar panel 25. As shown in FIG. 6, a
thermostat 30 and/or humistat 35 can be included for additional
control of the fan 20.
[0022] An optional charge-control device 78 and battery B can be
added for operations into nighttime, or when there is insufficient
sunlight to energize the solar panel 25. The charge control 78
automatically uses electricity from the solar panel 25 to charge
the battery B. It also provides over-current and over-voltage
protection to the battery B, fan 20, and wiring. The battery B and
the control 78 are mounted on the outside of the building under the
roof overhang, either to the overhang itself or a wall of the
building, with screws, a bracket, and a weathertight enclosure
adjacent to the fan 20 and solar panel 25 on the outside of the
soffit.
[0023] Mounting the fan 20 over the soffit vent 11 obviates the
necessity of attic entry, roof access, and the like. Use of the
roof-mounted solar panel 25 obviates the necessity of running
electrical power conductors from an external source, such as an
electrical power panel. Multiple soffit fans 20 can be configured
to service larger buildings.
[0024] As shown in FIG. 3, the fan 20 is preferably a low voltage,
direct current, coaxial fan having fan blades 39 and a motor M
mounted inside of a substantially arcuate shroud or housing 21a,
which extends into a substantially rectangular mounting base 21b.
The fan assembly 20 is chosen for suitability for exterior
applications, and for compatibility with the solar panel 25. A
protective screen 33 covers the intake/exhaust port of the housing
portion 21a.
[0025] The fan 20 preferably is an assembly that has a brushless
motor M, low inertia, low weight, and high-quality sealed bearings,
and is preferably constructed of non-corrosive materials. The fan
20 should run at 12-volts DC or less. The housing base 21b is
aligned with and covers the soffit vent opening 11 in a manner that
allows the fan to efficiently take in and discharge air, and is
secured in place with appropriate fasteners. The rectangular base
21b is flanged to allow screw mounting on the soffit peripheral to
the soffit vent 11. The cross-sectional area of the soffit opening
should be approximately the same as that of the fan 20. The fan
housing or cowl should completely cover the soffit opening 11 and
should be sealed at the edges around the base portion 21b to
prevent forced air leakage around the fan 20.
[0026] Intake or exhaust is accomplished by e.g., swapping
connectivity of the wire connectors to reverse voltage polarity in
order to change the direction of rotation of the motor M of the fan
20, or when motor direction is unchangeable, by e.g., reversing the
pitch of the fan blades with respect to the soffit opening.
Preferably, the fan 20 is located on the opposite side of the
structure from other attic ventilation openings, such as soffit
vents, ridge vents, or gable vents, in order to maximize the cross
flow of forced air through the attic.
[0027] Individual air movement, volume capacity, and the number of
fans 20 used are based on the volume of attic to be ventilated in
accordance with common industry standards.
[0028] The solar panel 25 is removably mounted with non-corrosive
fasteners via a pivotal attachment of its elongate, side frame
members 9c to a U-shaped bracket 9a, which is attached to the roof
edge board 13 (fascia) as close to the fan 20 as possible.
Alternatively the solar panel 25 is mounted on the fan housing to
minimize electrical losses from the run of power cable 40.
[0029] The pivotal support brackets 9b extend down from the solar
panel 25 and can be adjusted to rest on the top of the gutter G. In
the event of a pending tropical cyclone, the panel 25 can be
removed by loosening two screws (preferably thumbscrews) on the
U-shaped bracket 9a and disconnecting the cable 40. The solar panel
25 is oriented to maximize daylight striking the panel 25
throughout the day and throughout the year. Typically, this is with
a solar panel axis in an east-west orientation without sources of
shade during the day. The panel 25 should be tilted toward the sun
about the horizontal axis, the degree of tilt depending on the
latitude of the location. The tilt can be adjusted seasonally for
the declination of the sun's seasonal path for more direct
sunlight, or it can be held in a fixed position year round. The
solar panel 25 should be mounted to overhang free of structures,
thereby preventing overheating and loss of effectiveness.
[0030] The photovoltaic solar panel 25 has voltage, current, and
power (watts) ratings that are specifically matched to the motor M
of the fan 20. Low voltage, low resistance, insulated copper wire
cable 40 is connected with non-corrosive fasteners, hangars, and
plug disconnects.
[0031] As most clearly shown in FIG. 5, the solar panel positive
and negative wires are connected to their corresponding polarity
fan motor conductors, preferably with plug disconnects (plugs 50a
and 50c mating with receptacles 50b and 50d).
[0032] Sunlight strikes the solar panel 25. The solar panel 10
generates electricity and sends it by connecting wires to the fan
20. The blades 39 of the fan 20 spin, thereby drawing cool, ambient
outside air from under the soffit and sending it through the soffit
vent 11. The cool air enters the attic of the house H and mixes
with the heated or moisture-laden air of the attic, cooling and
drying it. It also displaces mixed air out of an opposing soffit,
ridge, or gable vent, thereby forcing the mixed air and the
entrained heat and moisture to the exterior of the building H. Two
units 10 may be connected in a push-pull airflow arrangement
through the attic.
[0033] The thermostat 30 and/or humistat 35 can control the start,
run, and stop cycles of the fan 20 according to preset desired
temperature and/or humidity. This can be advantageous in climates
and circumstances when the outside ambient air may be warmer,
cooler, or more humid that the attic air, and when a delay in
starting forced attic ventilation may be incrementally
advantageous.
[0034] Thermostat 30 is a normally open, fixed set point
temperature thermostat suitable for solar attic fan applications
and can be connected in series with the positive conductor of the
electrical circuit between each solar panel 25 and each fan motor
M. A normally open, fixed set point humistat 35 can be connected in
series in the positive wire of the electrical circuit between each
solar panel 25 and each fan motor M. Alternatively, the thermostat
30 is connected electrically in parallel with the humistat 35, and
the combination is connected in series in the positive wire of the
electrical circuit between each solar panel 25 and each fan motor
M.
[0035] The humistat 35 or parallel combination is mounted with
screws as far as practicable inside the soffit opening 11 for
accurate sensing of attic temperature and/or humidity.
[0036] The solar-powered soffit fan 10 may be configured in three
different modes. In one mode, the fan 20 is configured to draw
cool, ambient outside air from below the soffit into the attic. In
a second mode, the solar-powered soffit fan is configured to
exhaust hot air from the attic out to the exterior of the building
through the soffit vent. In a third mode, a first solar-powered
soffit fan is configured to blow cool outside air into the attic,
while a second solar-powered soffit fan is simultaneously
configured to exhaust hot air from the attic to the exterior of the
building, creating a push-pull airflow effect.
[0037] As shown in FIG. 7, an alternative embodiment fan assembly
720 includes a plurality of fans in a single unit. A wiring harness
702 electrically connects together individual fans of fan assembly
720. The female connectors 50b and 50d accept voltage to actuate
the fans. The fan assembly 720 includes a 16''.times.8'' standard
soffit vent louver-integral screen combination 711.
[0038] As shown in FIG. 8, fan assembly 720 fits into soffit
opening and connects to semi-rigid flexible ductwork 810 which
directs airflow between the soffit fan assembly 720 and the
building's attic portion.
[0039] It is to be understood that the present invention is not
limited to the embodiment described above, but encompasses any and
all embodiments within the scope of the following claims.
* * * * *