Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02877075 2015-01-08
Heating and Cooling Zone Control System
TECHNICAL FIELD
[001] This disclosure relates to heating and cooling systems. In
particular, this
disclosure relates to a zone control system for regulating temperatures in
different
sections or zones in a residential or commercial building.
BACKGROUND
[002] Air temperatures within residential buildings are typically
maintained by one
or more heating and cooling systems. Different types of heating and cooling
systems
are known and used. This disclosure is directed to forced air heating and
cooling
systems. These are commonly referred to as HVAC systems, where HVAC means
"heating, ventilation, air conditioning".
[003] In a traditional HVAC system, a single centrally located thermostat
is used to
control the temperature at or near a set-point temperature by switching
heating or
cooling devices (Furnace/Air condition) on or off. The thermostat has a sensor
to
determine the temperature in its immediate vicinity. In heating mode, if the
sensed
temperature is below the set-point temperature, the thermostat transmits a
signal to the
heating and air handling system to turn on. When temperature reaches the set-
point the
thermostat transmits a signal to the heating and air handling system to turn
off. In
cooling mode, if the sensed temperature is above the set-point temperature,
the
thermostat transmits a signal to the cooling and air handling system to turn
on. When
temperature reaches the set-point the thermostat transmits a signal to the
cooling and
air handling system to turn off. In some systems the heating or cooling part
of the
appliance may turn off and the air handling part continues to run.
[004] The central thermostat may be programmable to automatically or
manually
change the set-point to different temperatures over a 24 hour period and/or
for several
days, such as weekdays and weekend days.
[005] Heating and cooling residential spaces present several challenges to
an
HVAC system. Buildings may have multiple levels, rooms that face different
directions
(i.e. north, south, east or west), rooms having different window sizes, large
open rooms
with different ceiling heights, unfinished rooms, rooms over unheated garages
or crawl
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spaces, or rooms that are frequently used and others that are only used
occasionally.
These different environments often result in different room temperatures in
different
rooms or sections of a house. Moreover heating or cooling low use or unused
interior
spaces increases energy costs.
[006] One solution
to uneven heating and cooling within a residential building is to
divide the residential space into several zones or areas. A sensor or zone
thermostat is
provided for each room or zone for monitoring temperature in the zone. Such
systems
include a central controller and zone motorized dampers installed in the
ductwork for
each zone. When a zone needs to be heated or cooled, a signal is transmitted
by the
zone thermostat to the controller board. The controller board transmits a
signal to the
heating and cooling appliance and to one or more zone dampers causing the
dampers
to move to an open position to deliver conditioned air until the set point
condition of the
zone thermostat is met. When heating or cooling is not needed in a zone, the
damper
closes to save energy and maximize flow to other zones.
[007] The foregoing
zone system with dampers within ductwork can be sized and
more readily installed as part of a new construction but such damper systems
are
relatively expensive and are less suited and even more expensive to install
when
upgrading existing HVAC systems. The ducts in an existing residential building
are not
always accessible for installing the necessary motorized dampers. This results
in
considerable increased costs and a longer period of return on the capital cost
for an
upgraded HVAC system.
SUMMARY
[008] In one embodiment, the disclosure provides a new home HVAC zone
control
system comprising three basic units: a master thermostat, one or more slave
thermostats, and air distribution registers at the discharge ends of the HVAC
air flow
ducts.
[009] The master thermostat is programmable and controls the heating and
cooling
devices, such as a furnace and air conditioning unit. The master thermostat
can also
sense the temperature within its surrounding area. The master thermostat
receives and
transmits wireless signals to the slave thermostats. The master thermostat
also
processes system and operation data. The master thermostat may be controlled
via a
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thermostat LCD interface or remotely via one or more computer processing units
connected to a wired or wireless local area network (such as Wi-Fi or
Bluetooth) within
the residential space. If the residential network is connected to the
Internet, the master
thermostat may be controlled by computer processing units remote from the
residential
space. Computer processing units includes desk and laptop computers, tablets,
and cell
phones.
[0010] One or more slave thermostats are installed in different areas or
rooms within
the residential structure. A slave thermostat senses the temperature within
its
immediate area and transmits wireless signals to and may receive wireless
signals from
the master thermostat. A slave thermostat processes data received, such as its
area
temperature. A slave thermostat also transmits and receives signals to and
from one or
more registers located within the zone controlled by the slave thermostat.
[0011] Each air distribution register is provided with means to receive
wireless
signals from a slave thermostat and/or the master thermostat and means to
wirelessly
transmit signals to a slave thermostat and the master thermostat. Each
register is
provided with means to regulate the discharge air flow. A register may be
assigned or
paired with the master thermostat and/or a slave thermostat. The register
receives
commands from the master thermostat or slave thermostat to regulate the
discharge air
flow by opening and closing air vanes within the register.
[0012] The communication among master thermostat, slave thermostats and
registers may be by any wireless communication means. For example, an IEEE
802.15.4 standard RF (Radio Frequency) link with unlicensed frequency band may
be
used for such wireless communication. The Frequency Band used in North
American is
902-928MHz or 2400-2483.5MHz. For Europe, the Frequency Band is 868-868.6MHz.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] An embodiment will now be described in detail by way of example,
with
reference to the accompanying drawings in which:
[0014] Figure 1 is a block diagram of one embodiment of a zone control
system
according to the present disclosure.
[0015] Figure 2 is a block diagram of a master thermostat or
microcontroller of the
system in Figure 1.
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[0016] Figure 3 is a block diagram of a zone thermostat or
microcontroller of the
system in Figure 1.
[0017] Figure 4 is a block diagram of a register of the system in Figure
1.
DETAILED DESCRIPTION
[0018] The description, which follows, and the embodiments described
therein, are
provided by way of illustration of an example, or examples of particular
embodiments of
principles and aspects of the present invention. These examples are provided
for the
purposes of explanation, and not of limitation, of those principles and of the
invention. In
the description that follows, like parts are marked throughout the
specification and the
drawings with the same respective reference numerals.
[0019] Figure 1 shows one embodiment of the HVAC zone control system. A
centrally located master programmable thermostat or controller transmits and
receives
signals to the furnace/air conditioning appliance (also referred to as the
"air handling
appliance"). The master thermostat may be controlled via a thermostat
interface or
remotely via a wired or wireless local area network (such as Wi-Fi, Bluetooth
and other
wireless protocols) within the residential space. If the residential network
is connected
to the Internet, the master thermostat may also be controlled by remote
computers, cell
phones, tablets and similar devices. The master thermostat may be programmed
to
transmit and receive wireless signals to one or more room registers
discharging
conditioned air into a room or zone. For example, the master thermostat may
control
one or more registers in the room in which the master thermostat is located.
[0020] The master thermostat receives wireless signals from one or more
slave or
satellite thermostats located in different rooms or in zones comprising one or
more
rooms of the residential building. A slave thermostat senses temperature
within its
zone. Each slave thermostat may be set to the same or a different set-point
temperature than the set-point temperature of the master thermostat.
[0021] Each room has one or more registers for discharging conditioned
air into
each room. The registers are located at the end of a duct that supplies
conditioned air
from the air handling appliance. Each register has one or more vanes than may
be
automatically or manually opened or closed to adjust the discharge air flow
from the
register. Registers may be battery powered and have low battery audible and
visual
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alerts. Each register also has signal receiving and transmitting means and
motorized
means for opening and closing the vanes of the register. Each register may
also have
means for selecting different bands of wireless frequencies.
[0022] When the temperature in a zone falls below the slave thermostat
set-point
temperature (in the case of heating), the slave thermostat transmits a
wireless signal to
the master thermostat to turn on the air handling appliance. The slave
satellite transmits
a second wireless signal to the registers within its zone to activate the
motorized means
to open the vanes of each register. When the slave thermostat set-point
temperature is
met, the slave thermostat transmits a wireless signal to the master thermostat
to turn off
the air handling appliance. The slave thermostat may optionally also transmit
a wireless
signal to the registers to close the vanes of the registers. Each satellite
thermostat may
be set to use separate wireless band frequencies.
[0023] The communication among master thermostat, slave thermostats and
registers is by wireless ferquencies. An IEEE 802.15.4 standard RF (Radio
Frequency)
link with unlicensed frequency band is used in wireless communication. The
frequency
band commonly used in North America is 902-928MHz or 2400-2483.5MHz. For
Europe, the commonly used frequency band is 868-868.6MHz.
[0024] Figure 2 shows features of the master thermostat. The master
thermostat
has high-accuracy temperature measurement from 0 C to 35 C ( 0.5 C) with a
resolution 0.1 C.. The master thermostat has a LCD Screen which allows
programming
and display of mode of operation, fan level setting, temperature measurement
(celsius/fahrenheit), temperature setting, temperature schedules, setting real-
time-clock
(RTC) (12/24 hour format) with days of the week, and Wi-Fi network status. The
thermostat also has capacitive touch buttons, a Wi-Fi module, an 802.15.4
wireless
module, an AC and battery power supply, and furnace and cooling control.
[0025] Figure 3 shows features of a slave thermostat. A slave thermostat
has a
802.15.4 wireless module, status LEDs (battery, alarm), transmitting and
receiving
means for controlling the opening and closing of one or more registers within
its zone.
[0026] Figure 4 shows features of the registers used in the zone control
system. A
register comprises a microcontroller for transmitting and receiving wireless
signals, an
802.15.4 wireless module, a battery power supply, status LED lights (e.g.
battery,
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alarm), means for opening and closing vanes of the register and may optionally
include
battery power supply recharging by a solar panel.
[0027] While the embodiment has been described with reference to a
residential
building, the zone control system of the present disclosure may be used in
comparable
sized commercial and industrial buildings.
[0028] While the principles of the invention have been shown and
described in
connection with specific embodiments, it is to be understood that such
embodiments
are by way of example and are not limiting. As is evident from the foregoing
description,
certain aspects of the present invention are not limited by the particular
details of the
embodiment illustrated in the drawings. Other modifications and applications,
or
equivalents, will occur to those skilled in the art. The terms "having",
"comprising" and
"including" and similar terms as used in the foregoing specification are used
in the
sense of "optional" or "may include" and not as "required". Many changes,
modifications, variations and other uses and applications of the present
construction
will, however, become apparent to those skilled in the art after considering
the
specification and attached drawings. All such changes, modifications,
variations and
other uses and applications which do not depart from the scope of the
invention are
deemed to be covered by the invention which is limited only by the claims that
follow.
The scope of the disclosure is not intended to be limited to the embodiments
shown
herein, but is to be accorded the full scope consistent with the claims,
wherein
reference to an element in the singular is not intended to mean "one and only
one"
unless specifically so stated , but rather one or more.
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