U.S. patent application number 16/596494 was filed with the patent office on 2020-04-09 for building ventilation system.
The applicant listed for this patent is sysRAND Corporation. Invention is credited to Lee Johnson, Gary J. Rodriguez, George Swanson.
Application Number | 20200109870 16/596494 |
Document ID | / |
Family ID | 70052119 |
Filed Date | 2020-04-09 |
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United States Patent
Application |
20200109870 |
Kind Code |
A1 |
Rodriguez; Gary J. ; et
al. |
April 9, 2020 |
BUILDING VENTILATION SYSTEM
Abstract
The invention describes a ventilation system for a building. The
ventilation system compares interior air with exterior air and
exchanges the air when needed. Measuring both interior and exterior
air increases energy conservation and reduces the likelihood of
harmful contaminants in the building.
Inventors: |
Rodriguez; Gary J.; (Aurora,
CO) ; Swanson; George; (Austin, TX) ; Johnson;
Lee; (Littleton, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
sysRAND Corporation |
Parker |
CO |
US |
|
|
Family ID: |
70052119 |
Appl. No.: |
16/596494 |
Filed: |
October 8, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62742564 |
Oct 8, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24F 11/0001 20130101;
F24F 2110/22 20180101; F24F 2110/10 20180101; F24F 2110/65
20180101; F24F 2110/12 20180101; F24F 2110/20 20180101; F24F 7/10
20130101; F24F 13/24 20130101; F24F 2110/68 20180101; F24F 2110/72
20180101; F24F 7/08 20130101; F24F 11/74 20180101 |
International
Class: |
F24F 11/00 20060101
F24F011/00; F24F 7/08 20060101 F24F007/08; F24F 7/10 20060101
F24F007/10 |
Claims
1. A ventilation system for a building comprising: a. at least one
fan for directing air flow, b. at least one sensor capable of
providing at least one interior input and at least one exterior
input, and c. a controller that operates the fan when the interior
and exterior inputs exceed a differential.
2. The ventilation system of claim 1, wherein the fan is selected
from a group consisting of an intake fan and an exhaust fan.
3. The ventilation system of claim 1, wherein ventilation system
includes a plurality of fans.
4. The ventilation system of claim 1, wherein the fan is mounted in
a fan duct.
5. The ventilation system of claim 1, wherein the ventilation
system includes a plurality of ducts.
6. The ventilation system of claim 4, wherein the sensor is mounted
in the fan duct.
7. The ventilation system of claim 1, wherein the ventilation
system includes a plurality of sensors including at least one
interior sensor that provides the interior sensor input to the
controller and at least one exterior sensor that provides the
exterior sensor input to the controller.
8. The ventilation system of claim 1, wherein the sensor provides
the interior sensor input and the exterior sensor input by shared
sampling.
9. The ventilation system of claim 1, wherein the sensor is
selected from a group consisting of a humidity sensor, radon
detector, temperature sensor, allergen detector, pollutant
detector, carbon monoxide detector, hydrocarbon detector, and
combinations thereof.
10. The ventilation system of claim 1, wherein the air flow
produced by the fan is reversible.
11. The ventilation system of claim 10, wherein the direction of
air flow determines the interior input and exterior input to the
controller.
12. The ventilation system of claim 1, wherein the ventilation
system includes redundant sensors to ensure reliable operation.
13. The ventilation system of claim 1, wherein the controller
monitors resonance and dissonance attributes.
14. The ventilation system of claim 13, wherein the controller
algorithmically manages resonance and dissonance attributes to
improve operation.
15. The ventilation system of claim 14, wherein the operation may
be improved by varying signal conductance in tandem with impedance
variations.
16. The ventilation system of claim 1, wherein the controller
includes a group consisting of a programmable microprocessor, a
peripheral, memory, communications media, a logging device, and
combinations thereof.
17. The ventilation system of claim 1, wherein the controller is
programmed to improve power characteristic of the fan.
18. The ventilation system of claim 17, wherein power
characteristic is selected from a group consisting of current,
voltage, and the product of current and voltage.
19. The ventilation system of claim 17, wherein the fan has an
acoustic signature and at least one sensor input acquires the
acoustic signature of the fan.
20. The ventilation system of claim 19, wherein the fan is operated
at the acoustic signature with a lowest decibel reading.
Description
[0001] This application claims priority to U.S. provisional
application 62/742,564 filed 8 Oct. 2018.
FIELD OF THE INVENTION
[0002] The invention relates to an article and method for
ventilating contaminants from a building.
BACKGROUND OF THE INVENTION
[0003] Ventilation systems can be used to reduce humidity, toxins,
radioactive gases, pollutants, allergens and other unwanted
chemicals (collectively "contaminants") from buildings. Such
systems can produce either a positive or negative pressure gradient
between the building and the exterior that forces contaminants from
the building and replaces the contaminants with fresh air.
[0004] More generally, ventilation systems have included exhaust
systems, supply systems, balanced systems, and energy recovery
systems. These systems can include one or more fans, vents, or
ducts. They typically operate continuously; however, they can be
triggered by an event such as a timer or high humidity level.
[0005] An exhaust system includes an exhaust fan that draws air
from the building. Outside air can infiltrate through cracks,
windows, etc. to replace the exhausted air. A downside of exhaust
systems is the incoming outside air can draw in contaminants, such
as toxins, allergens, and humidity, and outside air may exhibit
temperatures that are excessively hot or cold, or humidity which is
excessively moist or dry. Any of these states may be detrimental to
the structure or the health of the inhabitants thereof. Humidity
can even condense inside the walls of the building thereby
promoting mold and mildew growth.
[0006] Supply systems produce a positive pressure inside the
building that forces out interior air. Outside air is drawn into
the building though a duct, and replaces the interior air forced
from the building. Unlike exhaust systems, supply systems permit
the incoming air to be filtered, thereby reducing particulate
contaminants. Supply systems do not typically remove gaseous
contaminants or particulates too small for the filter. Because
supply systems also do not remove moisture or adjust the
temperature of the incoming air, they are limited to drier and
warmer climates.
[0007] A balanced system can contain a plurality of fans that move
air into and out of a building. A first fan draws a volume of
outside air into the building through a first vent so the incoming
outside air can be filtered. A second fan exhausts a similar volume
of interior air from the building through a second vent. The need
for a plurality of fans and vents makes a balanced system costlier
than either an exhaust or supply system. Like exhaust and supply
systems, however, balanced systems cannot remove gaseous
contaminants, small particulates, and do not affect humidity or
temperature of the incoming or exhausted air.
[0008] Energy recovery systems permit exchange of both air and
heat. Like a balanced system, an energy recovery system includes a
plurality of fans and vents for transferring air between a building
and the outside. Energy recovery systems also include a heat
exchanger that transfers heat between the incoming and outgoing
air, thereby reducing heating and cooling costs. The transfer of
heat can also stabilize humidity levels in the building as warmer
air absorbs moisture from cooler air. Of course, an energy recovery
system is typically more expensive to purchase and install than
other types of systems. Further, energy recovery systems do not
eliminate gaseous contaminants or small particulates.
[0009] The energy efficiency of modern buildings restricts air
infiltration. Humidity trapped in the building can cause mold,
mildew, and decay. A solution in the prior art includes an exhaust
fan triggered by a humidity sensor, whereby humid air in a crawl
space is replaced by outside air. This solution fails when the
outside air is more humid than the air within the crawl space. This
can produce a runaway state, that is, a feedback loop that causes
the exhaust fan to run continuously as the humidity within the
crawl space increases. The ventilation system can reduce the
effectiveness of heating systems and other energy conservation
measures, such as insulation and double pane windows, because the
ventilation system can draw in large amounts of cold air.
[0010] A need exists for a ventilation system that operates as
needed to remove contaminates from a building without drawing in
even more contaminates or reducing the effectiveness of heating and
cooling systems. Current ventilation systems can result in more
contaminates and cold, humid air being drawn into a building. A
ventilation system should be able to monitor both interior and
exterior air quality and then move air either into or out of a
building as needed to reduce interior contaminants.
BRIEF DESCRIPTION OF THE DRAWING
[0011] FIG. 1 shows an embodiment of the invention as used to
ventilate a sub-basement.
[0012] FIG. 2 shows a schematic diagram for an embodiment of the
invention.
[0013] FIG. 3 shows an alternative schematic of the invention.
[0014] FIG. 4 depicts the cyclic nature of resonance and dissonance
impedance regions.
[0015] FIG. 5 depicts the periodic effects that resonance and
dissonance have on signals.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The invention describes a building ventilation system
comprising at least one fan, at least one duct or vent, at least
one sensor, and at least one controller. The fan can be reversible
and can be of any appropriate size, voltage, and air flow. In
embodiments, a plurality of fans can be used, including for example
at least one intake fan for intake air and at least one exhaust fan
for exhaust air. Ducts and vents can comprise, for example, metal
or plastic pipes with or without check valves. The ventilation
system can optionally include shutters to close the ducts or vents,
thereby restricting airflow. In embodiments, the fan can be
integrated into a duct or vent.
[0017] The sensor can detect contaminants including, but not
limited to, humidity, radon, temperature, allergens, and pollutants
such as carbon dioxide, carbon monoxide, or hydrocarbons.
Optionally, the ventilation system includes redundant sensors to
ensure reliable operation in case of failure of the primary sensor.
The sensor provides sensor inputs to the controller. Sensor inputs
can include interior sensor inputs and exterior sensor inputs. In
embodiments, the ventilation system includes a plurality of
sensors, including an interior sensor and an exterior sensor.
Generally, an interior sensor provides sensor input from the side
of the fan opposite the air flow, that is, the interior air input,
and the exterior sensor provides sensor input from the incoming
side of the air flow, that is, the exterior air input.
[0018] The controller comprises circuitry capable of receiving the
sensor inputs and operating the fan when the inputs exceed a
differential. Conveniently, the controller is a programmable
microprocessor and can include various peripherals, memory,
communications media, a logging device, and combinations thereof.
The controller can trigger the fan and direct airflow into or out
of the building. The ventilation system can be used for an entire
building but also in specific applications including, but not
limited to, attics, crawlspaces, and garages.
[0019] FIG. 1 shows a ventilation system of the present invention
comprising an air inlet and an air outlet. The ventilation system
also comprises a fan for circulating air, a plurality of sensors,
and a controller. Using inputs from the sensor, the controller can
control the fan. In embodiments, the speed and direction of the fan
can be adjusted based on sensor inputs, user and algorithm
setpoints. In other embodiments, at least one sensor provides input
to both the interior sensor and the exterior sensor by shared
sampling between interior air inputs and exterior air inputs.
[0020] In an embodiment, the ventilation system can be used in
building having raised floors and crawl spaces. For example, raised
floors mitigate the heaving and shrinking of bentonite clays on
which many buildings are constructed. Heaving and shrinkage can
damage concrete slabs, load bearing beams, walls, etc. The raised
floor increases costs and produces an enclosed volume that can
accelerate decay of construction materials, growth of fungus and
mildew, and accumulation of radioactive radon gas.
[0021] In embodiments, the interior sensor samples interior air
within the building and the exterior sensor samples exterior air
outside of the building. Preferably, the sensors are placed at
sample locations of interest. For example, the interior sensor can
be placed in a crawl space or attic where air quality might be
problematic. The sensors send inputs descriptive of the interior
and exterior air to the controller. The controller receives the
inputs and, based on the inputs, and algorithm setpoints,
determines whether air exchange is necessary. The controller may
turn the fan on, change the speed of the fan, or even reverse the
direction of airflow. Unlike prior art, the controller would not
trigger airflow based solely on an interior sensor, thereby
reducing the risk of a feedback event that would cause the fan to
run continuously and impair energy efficiency of the building. In
alternative embodiments, the controller can assist in heating or
cooling the building by moving air to take advantage of thermal
gradients between interior and exterior air. For example, an attic
heated during the day can be actively cooled by drawing in cool
night air, or merely ventilated during extreme heat.
[0022] In an alternative embodiment, a sensor of the ventilation
system can detect a pollutant, such as for example, carbon
monoxide. This could be used, for example, in homes and especially
garages. If the sensor input exceeds a safe level, the controller
could direct the fan to exhaust interior air, thereby reducing the
level of pollutant. In embodiments, the controller could also
trigger an alarm to warn residents of excessive levels of
pollutant. The alarm could be audible, visual, and even electronic
such as sending a text or email message to a designated person, or
monitoring service.
[0023] In embodiments, a plurality of sensors integrates with the
primary airflow of the fan. For example, humidity, temperature and
carbon monoxide sensors can be in close proximity on or near the
fan, thereby reducing the mass of wires. The controller can receive
inputs from the various sensors and based on its programming
operate the fan as needed.
[0024] The fan can be either AC or DC; however, DC operation
reduces wear parts, can operate with low power switched
transistors, are reversible, throttleable, and can provide
tachometer feedback to the controller. Further, DC operation can
reduce noise and vibration by controlling the RPM of the fan
blades. The controller can be programmed to adjust fan speed for
reduced noise and vibration. Alternatively, an accelerometer sensor
near the fan can provide input to the controller, which can adjust
fan speed automatically.
[0025] FIG. 4 depicts a typical resonance curve, which can be used
in a control loop to improve power use and reduce electronic and
audible noise. The length of a wire, cable, or waveguide is the
fundamental parameter that shapes the characteristic impedances of
a line, thereby shaping its resonance frequencies. Rotational
velocities may also determine acoustic noise, and secondary
oscillations. These attributes can be controlled algorithmically to
reduce signal amplitude thereby improving system operation, for
example, by reducing noise and undesirable vibration. Device
operation may be improved by varying signal conductance in tandem
with impedance variations. Proper use of this feedback reduces
wear-and-tear on both equipment and end users.
[0026] In FIG. 5 we can observe that signal conductance varies as
impedance varies.
[0027] The controller can comprise a programmable microprocessor
that would allow updates to its internal software. The controller
can be connected wirelessly, for example, Wi-Fi or Bluetooth, so
that data can be downloaded and uploaded. Users may interact with
the controller using an app or website address. Advantageously,
software that operates the controller can be improved using
uploaded date and the improved software can be downloaded into
existing ventilation systems.
[0028] The controller can also be programmed to improve power
characteristics of the fan. Such characteristic can include, for
example, current, voltage, or their product. One or more audio,
vibration, or accelerometer sensor inputs may be employed to
acquire the acoustic signature of the fan operating at an improved
power setting.
[0029] Typically, the acoustic signature of the fan at its quietest
or lowest vibration coincides with the preferred power setting,
that is, the preferred RPM setting for the fan. The quietest
setting can be the power setting having the lowest decibel reading.
Preferably, the controller is biased in favor of quieter operation
at the expense of a higher power setting.
Example 1
[0030] In prior art, a single humidity sensor could cause even
moister exterior air to be drawn into the building in a positive
feedback loop. A first example of the present ventilation system
includes a controller, a fan, an interior humidity sensor, and an
exterior humidity sensor. The controller is programmed to operate
the fan only when (a) the interior of the building exceeds a preset
humidity and (b) the exterior humidity is lower than the interior
by a preset differential. This avoids running the fan when air
exchange will produce no benefit and also reduces energy loss.
Example 2
[0031] A ventilation system comprises a fan, a switch, a reversible
fan, an interior humidity sensor, an interior temperature sensor,
an exterior humidity sensor, and an exterior temperature sensor.
See FIG. 2. The controller can be programmed to send a signal to
the switch when the differentials between the interior and exterior
sensors exceeds a preset limit. This limit can be operator defined
or pre-set into the controller. When the differential is exceeded,
the controller signals the switch which provides power to the fan.
Further, the controller can operate the fan in either forward or
reverse depending on the measured differential. Combining
temperature and humidity inputs avoids exhausting air when the
exterior air is near, at or below freezing, that is when the
building would experience significant loss of heat if exterior air
is drawn in. The exterior temperature sensor can disable the system
because humidity is not the problem in this scenario.
[0032] What is believed to be the best mode of the invention has
been described above. However, it will be apparent to those skilled
in the art that numerous variations of the type described could be
made to the present invention without departing from the spirit of
the invention. The scope of the present invention is defined by the
broad general meaning of the terms in which the claims are
expressed.
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