Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM AND METHOD FOR ZONE HEATING AND COOLING
Background of the Invention
Field of the Invention
The present invention relates to a system and method for directing heating and
cooling air from an air handler to various zones in a home or commercial
structure.
Description of the Related Art
Most traditional home heating and cooling systems have one centrally-located
thermostat that controls the temperature of the entire house. The thermostat
turns the
Heating, Ventilating, and Air-Conditioner (HVAC) system on or off for the
entire house.
The only way the occupants can control the amount of HVAC air to each room is
to
manually open and close the register vents throughout the house.
Zoned HVAC systems are common in commercial structures, and zoned systems
have been making inroads into the home market. In a zoned system, sensors in
each room
or group of rooms, or zones, monitor the temperature. The sensors can detect
where and
when heated or cooled air is needed. The sensors send information to a central
controller
that activates the zoning system, adjusting motorized dampers in the ductwork
and sending
conditioned air only to the zone in which it is needed. A zoned system adapts
to changing
conditions in one area without affecting other areas. For example, many two-
story houses
are zoned by floor. Because heat rises, the second floor usually requires more
cooling in the
summer and less heating in the winter than the first floor. A non-zoned system
cannot
completely accommodate this seasonal variation. Zoning, however, can reduce
the wide
variations in temperature between floors by supplying heating or cooling only
to the space
that needs it.
A zoned system allows more control over the indoor enviroiunent because the
occupants can decide which areas to heat or cool and when. With a zoned
system, the
occupants can program each specific zone to be active or inactive depending on
their needs.
For example, the occupants can set the bedrooms to be inactive during the day
while the
lcitchen and living areas are active.
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A properly zoned system can be up to 30 percent more efficient than a non-
zoned
system. A zoned system supplies warm or cool air only to those areas that
require it. Thus,
less energy is wasted heating and cooling spaces that are not being used.
In addition, a zoned system can sometimes allow the installation of smaller
capacity
equipment without compromising comfort. This reduces energy consumption by
reducing
wasted capacity.
Unfortunately, the equipment currently used in a zoned system is relatively
expensive. Moreover, installing a zoned HVAC system, or retrofitting an
existing system,
is far beyond the capabilities of most homeowners. Unless the homeowner has
specialized
training, it is necessary to hire a specially-trained professional HVAC
technician to
configure and install the system. This makes zoned HVAC systems expensive to
purchase
and install. The cost of installation is such that even though the zoned
system is more
efficient, the payback period on such systems is many years. Such expense has
severely
limited the growth of zoned HVAC systems in the general home market.
Summary
The system and method disclosed herein solves these and other problems by
providing an Electronically-Controlled Register vent (ECRV) that can be easily
installed by
a homeowner or general handyman. The ECRV can be used to convert a non-zoned
HVAC
system into a zoned system. The ECRV can also be used in connection with a
conventional
zoned HVAC system to provide additional control and additional zones not
provided by the
conventional zoned HVAC system. In one embodiment, the ECRV is configured have
a
size and form-factor that conforms to a standard manually-controlled register
vent. The
ECRV can be installed in place of a conventional manually-controlled register
vent-often
without the use of tools.
In one embodiment, the ECRV is a self-contained zoned system unit that
includes a
register vent, a power supply, a thermostat, and a motor to open and close the
register vent.
To create a zoned HVAC system, the homeowner can simply remove the existing
register
vents in one or more rooms and replace the register vents with the ECRVs. The
occupants
can set the thermostat on the EVCR to control the temperature of the area or
room
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containing the ECRV. In one embodiment, the ECRV includes a display that shows
the
programmed setpoint temperature. In one embodiment, the ECRV includes a
display that
shows the current setpoint temperature. In one embodiment, the ECRV includes a
remote
control interface to allow the occupants to control the ECRV by using a remote
control. In
one embodiment, the remote control includes a display that shows the
programmed
temperature and the current temperature. In one einbodiment, the reinote
control shows the
battery status of the ECRV.
In one embodiment, the EVCR includes a pressure sensor to measure the pressure
of the air in the ventilation duct that supplies air to the EVCR. In one
embodiment, the
EVCR opens the register vent if the air pressure in the duct exceeds a
specified value. In
one embodiment, the pressure sensor is configured as a differential pressure
sensor that
measures the difference between the pressure in the duct and the pressure in
the room.
In one embodiment, the ECRV is powered by an internal battery. A battery-low
indicator on the ECRV informs the homeowner wllen the battery needs
replacement. In one
embodiment, one or more solar cells are provided to recharge the batteries
when light is
available. In one embodiment, the register vent include a fan to draw
additional air from the
supply duct in order to compensate for undersized vents or zones that need
additional
heating or cooling air.
In one embodiment, one or more ECRVs in a zone communicate with a zone
thermostat. The zone thermostat measures the temperature of the zone for all
of the ECRVs
that control the zone. In one embodiment, the ECRVs and the zone thermostat
communicate by wireless communication methods, such as, for example, infrared
communication, radio-frequency communication, ultrasonic communication, etc.
In one
embodiment, the ECRVs and the zone thermostat communicate by direct wire
connections.
In one embodiment, the ECRVs and the zone thermostat communicate using
powerline
communication.
In one embodiment, one or more zone thermostats communicate witli a central
controller.
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In one embodiment, the EVCR and/or the zoned thermostat includes an occupant
sensor, such as, for example, an infrared sensor, motion sensor, ultrasonic
sensor, etc. The
occupants can program the EVCR or the zoned thermostat to bring the zone to
different
temperatures when the zone is occupied and when the zone is empty. In one
embodiment,
the occupants can program the EVCR or the zoned thermostat to bring the zone
to different
teinperatures depending on the time of day, the time of year, the type of room
(e.g.
bedroom, kitchen, etc.), and/or whether the room is occupied or empty. In one
embodiment,
various EVCRs and/or zoned thermostats thought a composite zone (e.g., a group
of zones
such as an entire house, an entire floor, an entire wing, etc.)
intercommunicate and change
the temperature setpoints according to whether the composite zone is empty or
occupied.
In one embodiment, the home occupants can provide a priority schedule for the
zones based on whether the zones are occupied, the time of day, the time of
year, etc. Thus,
for example, if zone corresponds to a bedroom a.nd zone corresponds to a
living room, zone
can be given a relatively lower priority during the day and a relatively
higher priority
during the night. As a second exainple, if zone corresponds to a first floor,
and zone
corresponds to a second floor, then zone can be given a higher priority in
summer (since
upper floors tend to be harder to cool) and a lower priority in winter (since
lower floors
tend to be harder to heat). In one embodiment, the occupants can specify a
weighted
priority between the various zones.
Brief Description of the Drawings
Figure 1 shows a home with zoned heating and cooling.
Figure 2 shows one example of a conventional manually-controlled register
vent.
Figure 3A is a front view of one embodiment of an electronically-controlled
register
vent.
Figure 3B is a rear view of the electronically-controlled register vent shown
in
Figure 3A.
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Figure 4 is a block diagram of a self-contained ECRV.
Figure 5 is a block diagram of a self-contained ECRV with a remote control.
Figure 6 is a block diagram of a locally-controlled zoned heating and cooling
system wherein a zone thermostat controls one or more ECRVs.
Figure 7A is a block diagram of a centrally-controlled zoned heating and
cooling
system wherein the central control system cominunicates with one or more zone
tliennostats and one or more ECRVs independently of the HVAC systein.
Figure 7B is a block diagram of a centrally-controlled zoned heating and
cooling
system wherein the central control system coinmunicates with one or more zone
thermostats and the zone thermostats communicate with one or more ECRVs.
Figure 8 is a block diagram of a centrally-controlled zoned heating and
cooling
system wherein a central control system communicates with one or more zone
thermostats
and one or more ECRVs and controls the HVAC system.
Figure 9 is a block diagram of an efficiency-monitoring centrally-controlled
zoned
heating and cooling system wherein a central control system communicates with
one or
more zone thermostats and one or more ECRVs and controls and monitors the HVAC
system.
Figure 10 is a block diagram of an ECRV for use in connection with the systems
shown in Figures 6-9.
Figure 11 is a block diagram of a basic zone thermostat for use in connection
with
the systems shown in Figures 6-9.
Figure 12 is a block diagram of a zone thermostat with remote control for use
in
connection with the systems shown in Figures 6-9.
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Figure 13 shows one embodiment of a central monitoring system.
Figure 14 is a flowchart showing one embodiment of an instruction loop for an
ECRV or zone therinostat.
Figure 15 is a flowchart showing one embodiment of an instruction and sensor
data
loop for an ECRV or zone thermostat.
Figure 16 is a flowchart showing one embodiment of an instruction and sensor
data
reporting loop for an ECRV or zone thermostat.
Figure 17 shows an ECRV configured to be used in connection with a
conventional
T-bar ceiling system found in many commercial structures.
Figure 18 shows an ECRV configured to use a scrolling curtain to control
airflow as
an alternative to the vanes shown in Figures 2 and 3.
Figure 19 is a block diagram of a control algorithm for controlling the
register
vents.
Detailed Description
Figure 1 shows a home 100 with zoned heating and cooling. In the home 100, an
HVAC system provides heating and cooling air to a system of ducts. Sensors 101-
105
monitor the temperature in various areas (zones) of the house. A zone can be a
room, a
floor, a group of rooms, etc. The sensors 101-105 detect where and when
heating or cooling
air is needed. Information from the sensors 101-105 is used to control
actuators that adjust
the flow of air to the various zones. The zoned system adapts to changing
conditions in one
area without affecting other areas. For example, many two-story houses are
zoned by floor.
Because heat rises, the second floor usually requires more cooling in the
summer and less
heating in the winter than the first floor. A non-zoned system cannot
completely
accommodate this seasonal variation. Zoning, however, can reduce the wide
variations in
temperature between floors by supplying heating or cooling only to the space
that needs it.
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Figure 2 shows one example of a conventional manually-controlled register vent
200. The register 200 includes one or more vanes 201 that can be opened or
closed to adjust
the amount of air that flows tlirough the register 200. Diverters 202 direct
the air in a
desired direction (or directions). The vanes 201 are typically provided to a
mechanical
mechanism so that the occupants can manipulate the vanes 201 to control the
amount of air
that flows out of the register 200. In some registers, the diverters 202 are
fixed. In some
registers, the diverters 202 are moveable to allow the occupants some control
over the
direction of the airflow out of the vent. Registers such as the register 200
are found
throughout homes that have a central HVAC system that provides heating and
cooling air.
Typically, relatively small rooms such as bedrooms and bathrooms will have one
or two
such register vents of varying sizes. Larger rooms, such as living rooms,
family rooms, etc.,
may have more than two such registers. The occupants of a home can control the
flow of
air through each of the vents by manually adjusting the vanes 201. When the
register vent
is located on the floor, or relatively low on the wall, such adjustment is
usually not
particularly difficult (unless the mechanism that controls the vanes 201 is
bent or rusted).
However, adjustment of the vanes 201 can be very difficult when the register
vent 200 is
located so high on the wall that it cannot be easily reached.
Figure 3 shows one embodiment of an Electronically-Controlled Register Vent
(ECRV) 300. The ECRV 300 can be used to implement a zoned heating and cooling
system. The ECRV 300 can also be used as a remotely control register vent in
places where
the vent is located so high on the wall that is cannot be easily reached. The
ECRV 300 is
configured as a replacement for the vent 200. This greatly simplifies the task
of retrofitting
a home by replacing one or more of the register vents 200 witli the ECRVs 300.
In one
embodiment, shown in Figure 3, the ECRV 300 is configured to fit into
approximately the
same size duct opening as the conventional register vent 200. In one
embodiinent, the
ECRV 300 is configured to fit over the duct opening used by the conventional
register vent
200. In one embodiment, the ECRV 300 is configured to fit over the
conventional register
200, thereby allowing the register 200 to be left in place. A control panel
301 provides one
or more visual displays and, optionally, one or more user controls. A housing
302 is
provided to house an actuator to control the vanes 201. In one embodiment, the
housing
302 can also be used to house electronics, batteries, etc.
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Figure 4 is a block diagram of a self-contained ECRV 400, which is one
embodiment of the ECRV 300 shown in Figures 3A and 3B and the ECRV shown in
Figure
18. In the ECRV 400, a temperature sensor 406 and a temperature sensor 416 are
provided
to a controller 401. The controller 401 controls an actuator system 409. In
one embodiment,
the actuator 409 provides position feedback to the controller 401. In one
embodiment, the
controller 401 reports actuator position to a central control systein and/or
zone thermostat.
The actuator system 409 provided mechanical movements to control the airflow
through
the vent. In one embodiment, the actuator system 409 includes an actuator
provided to the
vanes 201 or other air-flow devices to control the amount of air that flows
through the
ECRV 400 (e.g., the amount of air that flows from the duct into the room). In
one
embodiment, an actuator system includes an actuator provided to one or more of
the
diverters 202 to control the direction of the airflow. The controller 401 also
controls a
visual display 403 and an optional fan 402. A user input device 408 is
provided to allow the
user to set the desired room temperature. An optional sensor 407 is provided
to the
controller 401. In one embodiment, the sensor 407 includes an air pressure
and/or airflow
sensor. In one einbodiment, the sensor 407 includes a humidity sensor. A power
source 404
provides power to the controller 401, the fan 402, the display 403, the
temperature sensors
406, 416, the sensor 407, and the user input device 408 as needed. In one
embodiment, the
controller 401 controls the ainount of power provided to the fan 402, the
display 403, the
sensor 406, the sensor 416, the sensor 407, and the user input device 408. In
one
embodiment, an optional auxiliary power source 405 is also provided to provide
additional
power. The auxiliary power source is a supplementary source of electrical
power, such as,
for example, a battery, a solar cell, an airflow (e.g., wind-powered)
generator, the fan 402
acting as a generator, a nuclear- based electrical generator, a fuel cell, a
thennocouple, etc.
In one embodiment, the power source 404 is based on a non-rechargeable battery
and the auxiliary power source 405 includes a solar cell and a rechargeable
battery. The
controller 401 draws power from the auxiliary power source when possible to
conserve
power in the power source 404. When the auxiliary power source 405 is unable
to provide
sufficient power, then the controller 401 also draws power from the power
source 404.
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In an alternative embodiment, the power source 404 is configured as a
rechargeable
battery and the auxiliary power source 405 is configured as a solar cell that
recharges the
power source 404.
In one embodiment, the display 403 includes a flashing indicator (e.g., a
flashing
LED or LCD) when the available power from the power sources 404 and/or 405
drops
below a threshold level.
The home occupants use the user input device 408 to set a desired temperature
for
the vicinity of the ECRV 400. The display 403 shows the setpoint temperature.
In one
embodiment, the display 403 also shows the current room temperature. The
temperature
sensor 406 measures the temperature of the air in the room, and the
temperature sensor 416
measures the temperature of the air in the duct. If the room temperature is
above the
setpoint temperature, and the duct air temperature is below the room
temperature, then the
controller 401 causes the actuator 409 to open the vent. If the room
temperature is below
the setpoint temperature, and the duct air temperature is above the room
teinperature, then
the controller 401 causes the actuator 409 to open the vent. Otherwise, the
controller 401
causes the actuator 409 to close the vent. In other words, if the room
temperature is above
or below the setpoint temperature and the temperature of the air in the duct
will tend to
drive the room temperature towards the setpoint temperature, then the
controller 401 opens
the vent to allow air into the room. By contrast, if the room temperature is
above or below
the setpoint temperature and the temperature of the air in the duct will not
tend to drive the
room temperature towards the setpoint temperature, then the controller 401
closes the vent.
In one embodiment, the controller 401 is configured to provide a few degrees
of
hysteresis (often referred to as a thermostat deadband) around the setpoint
temperature in
order to avoid wasting power by excessive opening and closing of the vent.
In one embodiment, the controller 401 turns on the fan 402 to pull additional
air
from the duct. In one embodiment, the fan 402 is used when the room
temperature is
relatively far from the setpoint temperature in order to speed the movement of
the room
temperature towards the setpoint temperature. In one embodiment, the fan 402
is used
when the room temperature is changing relatively slowly in response to the
open vent. In
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one embodiment, the fan 402 is used when the room temperature is moving away
from the
setpoint and the vent is fully open. The controller 401 does not turn on or
run the fan 402
unless there is sufficient power available from the power sources 404, 405. In
one
embodiment, the controller 401 measures the power level of the power sources
404, 405
before turning on the fan 402, and periodically (or continually) when the fan
is on.
In one embodiment, the controller 401 also does not turn on the fan 402 unless
it
senses that there is airflow in the duct (indicating that the HVAC air-handler
fan is blowing
air into the duct). In one embodiment, the sensor 407 includes an airflow
sensor. In one
embodiment, the controller 401 uses the fan 402 as an airflow sensor by
measuring (or
sensing) voltage generated by the fan 402 rotating in response to air flowing
from the duct
through the fan and causing the fan to act as a generator. In one embodiment,
the controller
401 periodically stop the fan and checks for airflow fiom the duct.
In one embodiment, the sensor 406 includes a pressure sensor configured to
measure the air pressure in the duct. In one embodiment, the sensor 406
includes a
differential pressure sensor configured to measure the pressure difference
between the air in
the duct and the air outside the ECRV (e.g., the air in the room). Excessive
air pressure in
the duct is an indication that too inany vents may be closed (thereby creating
too much
baclc pressure in the duct and reducing airflow through the HVAC system). In
one
embodiment, the controller 401 opens the vent when excess pressure is sensed.
The controller 401 conserves power by turning off elements of the ECRV 400
that
are not in use. The controller 401 inonitors power available from the power
sources 404,
405. When available power drops below a low-power threshold value, the
controls the
actuator 409 to an open position, activates a visual indicator using the
display 403, and
enters a low-power mode. In the low power mode, the controller 401 monitors
the power
sources 404, 405 but the controller does not provide zone control functions
(e.g., the
controller does not close the actuator 409). When the controller senses that
sufficient power
has been restored (e.g., through recharging of one or more of the power
sources 404, 405,
then the controller 401 resumes normal operation.
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Figure 5 is a block diagram of a self-contained ECRV 500 with a remote control
interface 501. The ECRV 500 includes the power sources 404, 405, the
controller 401, the
fan 402, the display 403, the temperature sensors 406, 416, the sensor 407,
and the user
input device 408. The remote control interface 501 is provided to the
controller 401, to
allow the controller 401 to communicate with a remote control 502. The
controller 502
sends wireless signals to the remote control interface 501 using wireless
communication
such as, for example, infrared communication, ultrasonic communication, and/or
radio-
frequency communication.
In one embodiment, the communication is one-way, from the remote control 502
to
the controller 401. The remote control 502 can be used to set the temperature
setpoint, to
instruct the controller 401 to open or close the vent (either partially or
fully), and/or to turn
on the fan. In one embodiment, the communication between the remote control
502 and the
controller 401 is two-way communication. Two-way communication allows the
controller
401 to send information for display on the remote control 502, such as, for
example, the
current room teinperature, the power status of the power sources 404, 405,
diagnostic
information, etc.
The ECRV 400 described in connection witll Figure 4, and the ECRV 500
described
in connection with Figure 5 are configured to operate as self-contained
devices in a
relatively stand-alone mode. If two ECRVs 400, 500 are placed in the same room
or zone,
the ECRVs 400, 500 will not necessarily operate in unison. Figure 6 is a block
diagram of a
locally-controlled zoned heating and cooling systein 600 wherein a zone
thermostat 601
monitors the temperature of a zone 608. ECRVs 602, 603 are configured to
communicate
with the zone thermostat 601. One embodiment of the ECRVs 620-603 is shown,
for
example, in connection with Figure 10. In one embodiment, the zone thennostat
601 sends
control commands to the ECRVs 602-603 to cause the ECRVs 602-603 to open or
close. In
one embodiment, the zone thermostat 601 sends temperature information to the
ECRVs
602-603 and the ECRVs 602-603 detennine whether to open or close based on the
temperature information received from the zone thermostat 601. In one
embodiment, the
zone thermostat 601 sends information regarding the current zone temperature
and the
setpoint temperature to the ECRVs 602-603.
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In one embodiment, the ECRV 602 communicates with the ECRV 603 in order to
improve the robustness of the communication in the system 600. Thus, for
example, if the
ECRV 602 is unable to communicate with the zone thermostat 601 but is able to
communicate with the ECRV 603, then the ECRV 603 can act as a router between
the
ECRV 602 and the zone thermostat 601. In one embodiment, the ECRV 602 and the
ECRV
603 communicate to arbitrate opening and closing of their respective vents.
The system 600 shown in Figure 6 provides local control of a zone 608. Any
number of independent zones can be controlled by replicating the system 600.
Figure 7A is
a block diagram of a centrally-controlled zoned heating and cooling system
wherein a
central control system 710 communicates with one or more zone thermostats 707
708 and
one or more ECRVs 702-705. In the system 700, the zone thermostat 707 measures
the
temperature of a zone 711, and the ECRVs 702, 703 regulate air to the zone
711. The zone
thermostat 708 measures the temperature of a zone 712, and the ECRVs 704, 705
regulate
air to the zone 711. A central thermostat 720 controls the HVAC system 720.
Figure 7B is a bloclc diagram of a centrally-controlled zoned heating and
cooling
system 750 that is similar to the system 700 shown in Figure 7A. In Figure 7B,
the central
system 710 communicates with the zone thermostats 707, 708, the zone
thermostat 707
communicates with the ECRVs 702, 703, the zone thermostat 708 communicates
with the
ECRVs 704, 705, and the central system 710 communicates with the ECRVs 706,
707. In
the system 750, the ECRVs 702-705 are in zones that are associated with the
respective
zone thermostat 707, 708 that controls the respective ECRVs 702-705. The ECRVs
706,
707 are not associated with any particular zone thennostat and are controlled
directly by the
central system 710. One of ordinary skill in the art will recognize that the
communication
topology shown in Figure 7B can also be used in connection with the system
shown in
Figures 8 and 9.
The central system 710 controls and coordinates the operation of the zones 711
and
712, but the system 710 does not control the HVAC system 721. In one
embodiment, the
central system 710 operates independently of the thermostat 720. In one
embodiment, the
thermostat 720 is provided to the central system 710 so that the central
system 710 lcnows
when the thermostat is calling for heating, cooling, or fan.
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The central system 710 coordinates and prioritizes the operation of the ECRVs
702-
705. In one embodiment, the home occupants and provide a priority schedule for
the zones
711, 712 based on whether the zones are occupied, the time of day, the time of
year, etc.
Thus, for example, if zone 711 corresponds to a bedroom and zone 712
corresponds to a
living room, zone 711 can be given a relatively lower priority during the day
and a
relatively higher priority during the night. As a second example, if zone 711
corresponds to
a first floor, and zone 712 corresponds to a second floor, then zone 712 can
be given a
higher priority in summer (since upper floors tend to be harder to cool) and a
lower priority
in winter (since lower floors tend to be harder to heat). In one embodiment,
the occupants
can specify a weighted priority between the various zones.
Closing too many vents at one time is often a problem for central HVAC systems
as
it reduces airflow through the HVAC system, and thus reduces efficiency. The
central
system 710 can coordinate how many vents are closed (or partially closed) and
thus, ensure
that enough vents are open to maintain proper airflow through the system. The
central
system 710 can also manage airflow through the home such that upper floors
receive
relatively more cooling air and lower floors receive relatively more heating
air.
Figure 8 is a block diagram of a centrally-controlled zoned heating and
cooling
system 800. The system 800 is similar to the system 700 and includes the zone
thermostats
707, 708 to monitor the zones 711, 712, respectively, and the ECRVs 702-705.
The zone
thermostats 707, 708 and/or the ECRVs 702-705 communicate with a central
controller
810. In the system 800, the thermostat 720 is provided to the central system
810 and the
central system 810 controls the HVAC system 721 directly.
The controller 810 provides similar functionality as the controller 710.
However,
since the controller 810 also controls the operation of the HVAC system 721,
the controller
810 is better able to call for heating and cooling as needed to maintain the
desired
temperature of the zones 711, 712. If all, or substantially, all of the home
is served by the
zone thermostats and ECRVs, then the central thermostat 720 can be eliminated.
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In some circumstances, depending on the return air paths in the house, the
controller
810 can turn on the HVAC fan (without heating or cooling) to move air from
zones that are
too hot to zones that are too cool (or vice versa) without calling for heating
or cooling. The
controller 810 can also provide for efficient use of the HVAC system by
calling for heating
and cooling as needed, and delivering the heating and cooling to the proper
zones in the
proper amounts. If the HVAC system 721 provides multiple operating modes
(e.g., high-
. speed, low-speed, etc.), then the controller 810 can operate the HVAC system
721 in the
most efficient mode that provides the amount of heating or cooling needed.
Figure 9 is a block diagram of an efficiency-monitoring centrally-controlled
zoned
heating and cooling system 900. The system 900 is similar to the system 800.
In the system
900 the controller 810 is replaced by an efficiency-monitoring controller 910
that is
configured to receive sensor data (e.g., system operating temperatures, etc.)
from the
HVAC system 721 to monitor the efficiency of the HVAC system 721.
Figure 10 is a block diagram of an ECRV 1000 for use in connection with the
systems shown in Figures 6-9. The ECRV 1000 includes the power sources 404,
405, the
controller 401, the fan 402, the display 403, and, optionally the temperature
sensors 416
and the sensor 407, and the user input device 408. A communication system 1081
is
provided to the controller 401. The remote control interface 501 is provided
to the
controller 401, to allow the controller 401 to communicate with a remote
control 502. The
controller 502 sends wireless signals to the remote control interface 501
using wireless
coinmunication such as, for exainple, infrared communication, ultrasonic
communication,
and/or radio-frequency communication.
The communication system 1081 is configured to communicate with the zone
thennometer and, optionally, with the central controllers 710, 810, 910. In
one
embodiment, the cominunication system 1081 is configured to coinmunicate using
wireless
communication such as, for example, infrared communication, radio
communication, or
ultrasonic communication.
Figure 11 is a block diagram of a basic zone thermostat 1100 for use in
comiection
with the systems shown in Figures 6-9. In the zone thennostat 1100, a
temperature sensor
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1102 is provided to a controller 1101. User input controls 1103 are also
provided to the
controller 1101 to allow the user to specify a setpoint temperature. A visual
display 1110 is
provided to the controller 1101. The controller 1101 uses the visual display
1110 to show
the current temperature, setpoint temperature, power status, etc. The
communication system
1181 is also provided to the controller 1101. The power source 404 and,
optionally, 405 are
provided to provide power for the controller 1100, the controls 1101, the
sensor 1103, the
communication system 1181, and the visual display 1110.
In systems where a central controller 710,810,910 is used, the communication
method used by the zone thermostat 1100 to communicate with the ECRV 1000 need
not
be the same method used by the zone thermostat 1100 to communicate with the
central
controller 710,810,910. Thus, in one embodiment, the communication system 1181
is
configured to provide one type of communication (e.g., infrared, radio,
ultrasonic) with the
central controller, and a different type of communication with the ECRV 1000.
In one embodiment, the zone thermostat is battery powered. In one embodiment,
the
zone thermostat is configured into a standard light switch and receives
electrical power
from the ligllt switch circuit.
Figure 12 is a block diagram of a zone thermostat 1200 with remote control for
use
in connection with the systems shown in Figures 6-9. The thermostat 1200 is
similar to the
thermostat 1100 and includes, the temperature sensor 1102, the input controls
1103, the
visual display 1110, the communication system 1181, and the power sources 404,
405. In
the zone thermostat 1200, the remote control interface 501 is provided to the
controller
1101.
In one embodiment, an occupant sensor 1201 is provided to the controller 1101.
The occupant sensor 1201, such as, for example, an infrared sensor, motion
sensor,
ultrasonic sensor, etc. senses wlien the zone is occupied. The occupants can
program the
zone thermostat 1201 to bring the zone to different temperatures when the zone
is occupied
and when the zone is empty. In one embodiment, the occupants can program the
zoned
thermostat 1201 to bring the zone to different temperatures depending on the
time of day,
the time of year, the type of room (e.g. bedroom, kitchen, etc.), and/or
whether the room is
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occupied or empty. In one embodiment, a group of zones are combined into a
composite
zone (e.g., a group of zones such as an entire house, an entire floor, an
entire wing, etc.)
and the central system 710, 810, 910 changes the temperature setpoints of the
various zones
according to whether the composite zone is empty or occupied.
Figure 13 shows one embodiment of a central monitoring station console 1300
for
accessing the functions represented by the blocks 710, 810, 910 in Figures 7,
8, 9,
respectively. The station 1300 includes a display 1301 and a keypad 1302. The
occupants
can specify zone temperature settings, priorities, and thermostat deadbands
using the
central system 1300 and/or the zone thermostats. In one embodiment, the
console 1300 is
implemented as a hardware device. In one einbodiment, the console 1300 is
implemented
in software as a computer display, such as, for exainple, on a personal
computer. In one
embodiment, the zone control functions of the blocks 710, 810, 910 are
provided by a
computer program running on a control system processor, and the control system
processor
interfaces with personal computer to provide the console 1300 on the personal
computer.
In one embodiment, the zone control fiulctions of the blocks 710, 810, 910 are
provided by
a computer program running on a control system processor provided to a
hardware console
1300. In one embodiment, the occupants can use the Internet, telephone,
cellular telephone,
pager, etc. to remotely access the central system to control the temperature,
priority, etc. of
one or more zones.
Figure 14 is a flowchart showing one einbodiment of an instruction loop
process
1400 for an ECRV or zone thermostat. The process 1400 begins at a power-up
block 1401.
After power up, the process proceeds to an initialization block 1402. After
initialization, the
process advances to a "listen" block 1403 wherein the ECRV or zone thermostat
listens for
one or more instructions. If a decision block 1404 detennines that an
instruction has been
received, then the process advances to a"perfonn instruction" block 1405,
otherwise the
process returns to the listen block 1403.
For an ECRV, the instructions can include: open vent, close vent, open vent to
a
specified partially-open position, report sensor data (e.g., airflow,
temperature, etc.), report
status (e.g, battery status, vent position, etc.), and the like. For a zone
thermostat, the
instructions can include: report temperature sensor data, report temperature
rate of change,
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report setpoint, report status, etc. In systems where the central system
communicates with
the ECRVs through a zone thermostat, the instructions can also include: report
number of
ECRVs, report ECRV data (e.g., temperature, airflow, etc.), report ECRV vent
position,
change ECRV vent position, etc.
In one embodiment, the listen block 1403 consumes relatively little power,
thereby
allowing the ECRV or zone thermostat to stay in the loop corresponding to the
listen block
1403 and conditional branch 1404 for extended periods of time.
Althougll the listen block 1403 can be implemented to use relatively little
power, a
sleep block can be implemented to use even less power. Figure 15 is a
flowchart showing
one embodiment of an instruction and sensor data loop process 1500 for an ECRV
or zone
thermostat. The process 1500 begins at a power-up block 1501. After power up,
the process
proceeds to an initialization block 1502. After initialization, the process
advances to a
"sleep" block 1503 wherein the ECRV or zone thermostat sleeps for a specified
period of
time. When the sleep period expires, the process advances to a wakeup block
1504 and then
to a decision 1505. In the decision block 1505, if a fault is detected, then a
transmit fault
block 1506 is executed. The process then advances to a sensor block 1507
wllere sensor
readings are taken. After taking sensor readings, the process advances to a
listen-for-
instructions block 1508. If an instruction has been received, then the process
advances to a
"perform instruction" block 1510; otherwise, the process returns to the sleep
block 1503.
Figure 16 is a flowchart showing one embodiment of an instruction and sensor
data
reporting loop process 1600 for an ECRV or zone thermostat. The process 1600
begins at a
power-up block 1601. After power up, the process proceeds to an initialization
block 1602.
After initialization, the process advances to a check fault block 1603. If a
fault is detected
then a decision block 1604 advances the process to a transmit fault block
1605; otherwise,
the process advances to a sensor bloclc 1606 where sensor readings are taken.
The data
values from one or more sensors are evaluated, and if the sensor data is
outside a specified
range, or if a timeout period has occurred, then the process advances to a
transmit data
block 1608; otherwise, the process advances to a sleep block 1609. After
transmitting in the
transmit fault bloclc 1605 or the transmit sensor data block 1608, the process
advances to a
listen block 1610 where the ECRV or zone thermostat listens for instructions.
If an
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instruction is received, then a decision block advances the process to a
perform instruction
block 1612; otherwise, the process advances to the sleep block 1609. After
executing the
perform instruction block 1612, the process transmits an "instruction complete
message"
and returns to the listen block 1610.
The process flows shown in Figures 14-16 show different levels of interaction
between devices and different levels of power conservation in the ECRV and/or
zone
thermostat. One of ordinary skill in the art will recognize that the ECRV and
zone
thermostat are configured to receive sensor data and user inputs, report the
sensor data and
user inputs to other devices in the zone control system, and respond to
instructions from
other devices in the zone control system. Thus the process flows shown in
Figures 14-16
are provided for illustrative purposes and not by way of limitation. Other
data reporting and
instruction processing loops will be apparent to those of ordinary skill in
the art by using
the disclosure herein.
In one embodiment, the ECRV and/or zone tllermostat "sleep," between sensor
readings. In one embodiment, the central system 710 sends out a"wake up"
signal. When
an ECRV or zone thermostat receives a wake up signal, it takes one or more
sensor
readings, encodes it into a digital signal, and transmits the sensor data
along with an
identification code.
In one embodiment, the ECRV is bi-directional and configured to receive
instructions from the central system. Thus, for example, the central system
can instruct the
ECRV to: perform additional measurements; go to a standby mode; wake up;
report battery
status; change wake-up interval; run self-diagnostics and report results; etc.
In one embodiment, the ECRV provides two wake-up modes, a first wake-up mode
for taking measurements (and reporting such measurements if deemed necessary),
and a
second walce-up mode for listening for commands from the central system. The
two wake-
up modes, or combinations thereof, can occur at different intervals.
In one embodiment, the ECRVs use spread-spectrum techniques to communicate
with the zone thermostats and/or the central system. In one embodiment, the
ECRVs use
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frequency-hopping spread-spectrum. In one embodiment, each ECRV has an
Identification
code (ID) and the ECRVs attaches its ID to outgoing cormnunication packets. In
one
embodiment, when receiving wireless data, each ECRV ignores data that is
addressed to
other ECRVs.
In one embodiment, the ECRV provides bi-directional communication and is
configured to receive data and/or instructions from the central system. Thus,
for exainple,
the central system can instruct the ECRV to perform additional measurements,
to go to a
standby mode, to wake up, to report battery status, to change wake-up
interval, to run self-
diagnostics and report results, etc. In one embodiment, the ECRV reports its
general health
and status on a regular basis (e.g., results of self-diagnostics, battery
health, etc.)
In one embodiment, the ECRV use spread-spectrum techniques to communicate
with the central system. In one embodiment, the ECRV uses frequency-hopping
spread-
spectrum. In one embodiment, the ECRV has an address or identification (ID)
code that
distinguishes the ECRV from the other ECRVs. The ECRV attaches its ID to
outgoing
communication paclcets so that transmissions from the ECRV can be identified
by the
central system. The central system attaches the ID of the ECRV to data and/or
instructions
that are transmitted to the ECRV. In one embodiment, the ECRV ignores data
and/or
instructions that are addressed to other ECRVs.
In one embodiment, the ECRVs, zone thermostats, central system, etc.,
communicate on a 900 MHz frequency band. This band provides relatively good
transmission through walls and other obstacles normally found in and around a
building
structure. In one embodiment, the ECRVs and zone thermostats communicate with
the
central system on bands above and/or below the 900 MHz band. In one
embodiment, the
ECRVs and zone thermostats listen to a radio frequency channel before
transmitting on that
channel or before beginning transmission. If the channel is in use, (e.g., by
another device
such as another central system, a cordless telephone, etc.) then the ECRVs
and/or zone
thermostats change to a different channel. In one embodiment, the sensor,
central system
coordinates frequency hopping by listening to radio frequency channels for
interference
and using an algorithm to select a next channel for transmission that avoids
the
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interference. In one embodiment, the ECRV and/or zone thermostat transmits
data until it
receives an acknowledgement from the central system that the message has been
received.
Frequency-hopping wireless systems offer the advantage of avoiding other
interfering signals and avoiding collisions. Moreover, there are regulatory
advantages given
to systems that do not transmit continuously at one frequency. Chamlel-hopping
transmitters change frequencies after a period of continuous transmission, or
when
interference is encountered. These systems may have higher transmit power and
relaxed
limitations on in-band spurs.
In one embodiment, the controller 401 reads the sensors 406, 407, 416 at
regular
periodic intervals. In one embodiment, the controller 401 reads the sensors
406, 407, 416 at
random intervals. In one einbodiment, the controller 401 reads the sensors
406, 407, 416 in
response to a walce-up signal from the central system. In one embodiment, the
controller
401 sleeps between sensor readings.
In one embodiment, the ECRV transmits sensor data until a handshaking-type
aclcnowledgement is received. Thus, rather than sleep if no instructions or
acknowledgements are received after transmission (e.g., after the instruction
block 1510,
1405, 1612 and/or the transmit blocks 1605, 1608) the ECRV retransmits its
data and waits
for an acknowledgement. The ECRV continues to transmit data and wait for an
aclrnowledgement until an acknowledgement is received. In one einbodiment, the
ECRV
accepts an acknowledgement from a zone thermometer and it then becomes the
responsibility of the zone thermometer to make sure that the data is forwarded
to the central
system. The two-way communication ability of the ECRV and zone thermometer
provides
the capability for the central system to control the operation of the ECRV
and/or zone
thermometer and also provides the capability for robust handshaking-type
communication
between the ECRV, the zone thermometer, and the central system.
In one embodiment of the system 600 shown in Figure 6, the ECRVs 602, 603 send
duct temperature data to the zone thermostat 601. The zone thermostat 601
compares the
duct temperature to the room temperature and the setpoint temperature and
makes a
determination as to whether the ECRVs 602, 603 should be open or closed. The
zone
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thermostat 601 then sends commands to the ECRVs 602, 603 to open or close the
vents. In
one embodiment, the zone thermostat 601 displays the vent position on the
visual display
1110.
In one embodiment of the system 600 shown in Figure 6, the zone thermostat 601
sends setpoint information and current room temperature information to the
ECRVs 602,
603. The ECRVs 602, 603 compare the duct temperature to the room temperature
and the
setpoint temperature and makes a determination as to whether to open or close
the vents. In
one embodiment, the ECRVs 602, 603 send information to the zone thermostat 601
regarding the relative position of the vents (e.g., open, closed, partially
open, etc.).
In the systems 700, 750, 800, 900 (the centralized systems) the zone
thermostats
707, 708 send room temperature and setpoint temperature information to the
central
system. In one embodiment, the zone thermostats 707, 708 also send temperature
slope
(e.g., temperature rate of rise or fall) information to the central system. In
the systems
where the thermostat 720 is provided to the central system or where the
central system
controls the HVAC system, the central system knows whether the HVAC system is
providing heating or cooling; otherwise, the central system used duct
temperature
information provide by the ECRVs 702-705 to detennine whether the HVAC system
is
heating or cooling. In one embodiinent, ECRVs send duct temperature
information to the
central system. In one embodiment, the central system queries the ECRVs by
sending
instructions to one or more of the ECRVs 702-705 instructing the ECRV to
transmit its
duct temperature.
The central system determines how inuch to open or close ECRVs 702-705
according to the available heating and cooling capacity of the HVAC system and
according
to the priority of the zones and the difference between the desired
temperature and actual
temperature of each zone. In one embodiment, the occupants use the zone
thermostat 707 to
set the setpoint and priority of the zone 711, the zone thermostat 708 to set
the setpoint and
priority of the zone 712, etc. In one embodiment, the occupants use the
central system
console 1300 to set the setpoint and priority of each zone, and the zone
thennostats to
override (either on a permanent or teinporary basis) the central settings. In
one
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embodiment, the central console 1300 displays the current temperature,
setpoint
teinperature, temperature slope, and priority of each zone.
In one embodiment, the central system allocates HVAC air to each zone
according
to the priority of the zone and the temperature of the zone relative to the
setpoint
temperature of the zone. Thus, for example, in one embodiment, the central
system
provides relatively more HVAC air to relatively higher priority zones that are
not at their
temperature setpoint than to lower priority zones or zones that are at or
relatively near their
setpoint temperature. In one einbodiment, the central system avoids closing or
partially
closing too many vents in order to avoid reducing airflow in the duct below a
desired
minimum value.
In one embodiment, the central system monitors a temperature rate of rise (or
fall)
in each zone and sends commands to adjust the amount each ECRV 702-705 is open
to
bring higher priority zones to a desired temperature without allowing lower-
priority zones
to stray too far form their respective setpoint temperature.
In one embodiment, the central system uses predictive modeling to calculate an
amount of vent opening for each of the ECRVs 702-705 to reduce the number of
times the
vents are opened and closed and thereby reduce power usage by the actuators
409. In one
embodiment, the central system uses a neural network to calculate a desired
vent opening
for each of the ECRVs 702-705. In one einbodiment, various operating
parameters such as
the capacity of the central HVAC system, the volume of the house, etc., are
programmed
into the central system for use in calculating vent openings and closings. In
one
embodiment, the central system is adaptive and is configured to learn
operating
characteristics of the HVAC system and the ability of the HVAC system to
control the
temperature of the various zones as the ECRVs 702-705 are opened and closed.
In an
adaptive learning system, as the central system controls the ECRVs to achieve
the desired
temperature over a period of time, the central system learns which ECRVs need
to be
opened, and by how much, to achieve a desired level of heating and cooling for
each zone.
The use of such an adaptive central system is convenient because the installer
is not
required to program HVAC operating parameters into the central system. In one
embodiment, the central system provides warnings when the HVAC system appears
to be
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operating abnormally, such as, for example, when the temperature of one or
more zones
does not change as expected (e.g., because the HVAC system is not operating
properly, a
window or door is open, etc.).
In one embodiment, the adaptation and learning capability of the central
system
uses different adaptation results (e.g., different coefficients) based on
whether the HVAC
system is heating or cooling, the outside temperature, a change in the
setpoint temperature
or priority of the zones, etc. Thus, in one einbodiment, the central system
uses a first set of
adaptation coefficients when the HVAC system is cooling, and a second set of
adaptation
coefficients wllen the HVAC system is heating. In one embodiment, the
adaptation is based
on a predictive model. In one embodiment, the adaptation is based on a neural
networlc.
Figure 17 shows an ECRV 1700 configured to be used in connection with a
conventional T-bar ceiling system found in inany commercial structures. In the
ECRV
1700, an actuator 1701 (as one embodiment of the actuator 409) is provided to
a damper
1702. The dainper 1702 is provided to a diffuser 1703 that is configured to
mount in a
conventional T-bar ceiling system. The ECRV 1700 can be coimected to a zoned
thermostat or central system by wireless or wired communication.
In one embodiment, the sensors 407 in the ECRVs include airflow and/or air
velocity sensors. Data from the sensors 407 are transmitted by the ECRV to the
central
system. The central system uses the airflow and/or air velocity measurements
to determine
the relative amount of air through each ECRV. Thus, for example, by using
airflow/velocity measurements, the central system can adapt to the relatively
lower airflow
of smaller ECRVs and ECRVs that are situated on the duct further from the HVAC
blower
than ECRVs which are located closer to the blower (the closer ECRVs tend to
receive more
airflow).
In one embodiment, the sensors 407 include humidity sensors. In one
embodiment,
the zone thermostat 1100 includes a zone humidity sensor provided to the
controller 1101.
The zone control system (e.g., the central system, the zone thermostat, and/or
ECRV) uses
humidity information from the humidity sensors to calculate zone comfort
values and to
adjust the temperature setpoint according to a comfort value. Thus, for
example, in one
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embodiment during a summer cooling season, the zone control system lowers the
zone
temperature setpoint during periods of relative high humidity, and raises the
zone setpoint
during periods of relatively low humidity. In one embodiment, the zone
thermostat allows
the occupants to specify a comfort setting based on temperature and humidity.
In one
5' embodiment, the zone control system controls the HVAC system to add or
reinove
humidity from the heating/cooling air.
Figure 18 shows a register vent 1800 configured to use a scrolling curtain
1801 to
control airflow as an alternative to the vanes shown in Figures 2 and 3. An
actuator 1802
(one embodiment of the actuator 409) is provided to the curtain 1801 to move
the curtain
1801 across the register to control the size of a register airflow opening. In
one
embodiment, the curtain 1801 is guided and held in position by a track 1803.
In one einbodiment, the actuator 1802 is a rotational actuator and the
scrolling
curtain 1801 is rolled around the actuator 1802, and the register vent 1800 is
open and rigid
enough to be pushed into the vent opening by the actuator 1802 when the
actuator 1802
rotates to unroll the curtain 1801.
In one embodiment, the actuator 1802 is a rotational actuator and the
scrolling
curtain 1801 is rolled around the actuator 1802, and the register vent 1800 is
open and rigid
enough to be pushed into the vent opening by the actuator 1802 when the
actuator 1802
rotates to unroll the curtain 1801. In one embodiment, the actuator 1802 is
configured to
Figure 19 is a block diagram of a control algorithm 1900 for controlling the
register
vents. For purposes of explanation, and not by way of limitation, the
algorithm 1900 is
described herein as running on the central system. However, one of ordinary
slcill in the art
will recognize that the algorithm 1900 can be run by the central system, by
the zone
thermostat, by the ECRV, or the algorithm 1900 can be distributed among the
central
system, the zone thermostat, and the ECRV. In the algorithm 1900, in a block
1901 of the
algorithm 1900, the setpoint temperatures from one or more zone thermostats
are provided
to a calculation block 1902. The calculation block 1902 calculates the
register vent settings
(e.g., how much to open or close each register vent) according to the zone
temperature, the
zone priority, the available heating and cooling air, the previous register
vent settings, etc.
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as described above. In one embodiment, the block 1902 uses a predictive model
as
described above. In one embodiment, the block 1902 calculates the register
vent settings
for each zone independently (e.g., without regard to interactions between
zones). In one
embodiment, the block 1902 calculates the register vent settings for each zone
in a coupled-
zone mamier that includes interactions between zones. In one embodiment, the
calculation
block 1902 calculates new vent openings by talcing into account the current
vent openings
and in a manner configured to minimize the power consumed by opening and
closing the
register vents.
Register vent settings from the block 1902 are provided to each of the
register vent
actuators in a block 1903, wherein the register vents are moved to new opening
positions as
desired (and, optionally, one or more of the fans 402 are turned on to pull
additional air
fiom desired ducts). After setting the new vent openings in the block 1903,
the process
advances to a block 1904 where new zone temperatures are obtained from the
zone
thermostats (the new zone teinperatures being responsive to the new register
vent settings
made in block 1903). The new zone temperatures are provided to an adaptation
input of the
block 1902 to be used in adapting a predictive model used by the block 1902.
The new
zone temperatures also provided to a temperature input of the block 1902 to be
used in
calculating new register vent settings.
As described above, in one embodiment, the algorithm used in the calculation
block
1902 is configured to predict the ECRV opening needed to bring each zone to
the desired
temperature based on the current temperature, the available heating and
cooling, the
amount of air available through each ECRV, etc. The calculating block uses the
prediction
model to attempt to calculate the ECRV openings needed for relatively long
periods of time
in order to reduce the power consumed in unnecessarily by opening and closing
the register
vents. In one embodiment, the ECRVs are battery powered, and thus reducing the
movement of the register vents extends the life of the batteries. In one
embodiment, the
block 1902 uses a predictive model that learns the characteristics of the HVAC
system and
the various zones and thus the model prediction tends to improve over time.
In one embodiment, the zone thermostats report zone temperatures to the
central
system and/or the ECRVs at regular intervals. In one embodiment, the zone
thermostats
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report zone temperatures to the central system and/or the ECRVs after the zone
temperature
has changed by a specified amount specified by a threshold value. In one
embodiment, the
zone thermostats report zone temperatures to the central system and/or the
ECRVs in
response to a request instruction from the central system or ECRV.
In one embodiment, the zone thermostats report setpoint temperatures and zone
priority values to the central system or ECRVs whenever the occupants change
the setpoint
temperatures or zone priority values using the user controls 1102. In one
embodiment, the
zone thermostats report setpoint temperatures and zone priority values to the
central system
or ECRVs in response to a request instruction from the central system or
ECRVs.
In one embodiment, the occupants can choose the thermostat deadband value
(e.g.,
the hysteresis value) used by the calculation block 1902. A relatively larger
deadband value
reduces the movement of the register vent at the expense of larger temperature
variations in
the zone.
In one embodiment, the ECRVs report sensor data (e.g., duct temperature,
airflow,
air velocity, power status, actuator position, etc.) to the central system
and/or the zone
thermostats at regular intervals. In one embodiment, the ECRVs report sensor
data to the
central system and/or the zone thennostats whenever the sensor data fails a
threshold test
(e.g., exceeds a threshold value, falls below a tlireshold value, falls inside
a threshold range,
or falls outside a threshold range, etc.). In one embodiment, the ECRVs report
sensor data
to the central system and/or the zone thermostats in response to a request
instruction from
the central system or zone thermostat.
In one embodiment, the central system is shown in Figures 7-9 is implemented
in a
distributed fashion in the zone thermostats 1100 and/or in the ECRVs. In the
distributed
system, the central system does not necessarily exists as a distinct device,
rather, the
functions of the central system can be are distributed in the zone thermostats
1100 and/or
the ECRVs. Thus, in a distributed system, Figures 7-9 represent a
conceptual/coinputational model of the system. For example, in a distributed
system, each
zone thermostat 100 knows its zone priority, and the zone thermostats 1100 in
the
distributed system negotiate to allocate the available heating/cooling air
among the zones.
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In one embodiment of a distributed system, one of the zone thermostat assuines
the role of
a master thermostat that collects data from the other zone thermostats and
impleinents the
calculation block 1902. In one embodiment of a distributed system, the zone
thermostats
operate in a peer-to-peer fashion, aiid the calculation block 1902 is
implemented in a
distributed mamler across a plurality of zone thermostats and/or ECRVs.
In one embodiment, the fans 402 can be used as generators to provide power to
recharge the power source 404 in the ECRV. However, using the fan 402 in such
a manner
restricts airflow through the ECRV. In one embodiment, the controller 401
calculates a
vent opening for the ECRV to produce the desired amount of air through the
ECRV while
using the fan to generate power to recharge the power source 404 (thus, in
such
circumstance) the controller would open the vanes more than otherwise
necessary in order
to compensate for the air resistance of the generator fan 402. In one
embodiment, in order
to save power in the ECRV, rather than increase the vane opening, the
controller 401 can
use the fan as a generator. The controller 401 can direct the power generated
by the fan 402
into one or both of the power sources 404, 405, or the controller 401 can dump
the excess
power from the fan into a resistive load. In one embodiment, the controller
401 makes
decisions regarding vent opening versus fan usage. In one embodiment, the
central system
instructs the controller 401 when to use the vent opening and wlien to use the
fan. In one
embodiment, the controller 401 and central system negotiate vent opening
versus fan usage.
In one embodiment, the ECRV reports its power status to the central system or
zone
thermostat. In one embodiment the central system or zone thermostat takes such
power
status into account when determining new ECRV openings. Tl1us, for example, if
there are
first and second ECRVs serving one zone and the central system knows that the
first
ECRVs is low on power, the central system will use the second ECRV to modulate
the air
into the zone. If the first ECRV is able to use the fan 402 or other airflow-
based generator
to generate electrical power, the central system will instruct the second ECRV
to a
relatively closed position in and direct relatively more airflow through the
first ECRV
when directing air into the zone.
It will be evident to those skilled in the art that the invention is not
limited to the
details of the foregoing illustrated embodiments and that the present
invention may be
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embodied in other specific forms without departing from the spirit or
essential attributed
thereof; furthermore, various omissions, substitutions and changes may be made
without
departing from the spirit of the inventions. For example, although specific
embodiments are
described in terms of the 900 MHz frequency band, one of ordinary skill in the
art will
recognize that frequency bands above and below 900 MHz can be used as well.
The
wireless system can be configured to operate on one or more frequency bands,
such as, for
example, the HF band, the VHF band, the UHF band, the Microwave band, the
Millimeter
wave band, etc. One of ordinary skill in the art will further recognize that
techniques other
than spread spectruin can also be used and/or can be used instead spread
spectrum. The
modulation uses is not limited to any particular modulation method, such that
modulation
scheme used can be, for example, frequency modulation, phase modulation,
amplitude
modulation, combinations thereof, etc. The one or more of the wireless
cominunication
systems described above can be replaced by wired communication. The one or
more of the
wireless communication systems described above can be replaced by powerline
networking
communication. The foregoing description of the embodiments is, tlierefore, to
be
considered in all respects as illustrative and not restrictive, with the scope
of the invention
being delineated by the appended claims and their equivalents.
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