U.S. patent application number 17/215607 was filed with the patent office on 2021-07-15 for method of auto association of hvac energy with control signal for self diagnostics of the hvac system.
This patent application is currently assigned to EnTouch Controls Inc.. The applicant listed for this patent is EnTouch Controls Inc.. Invention is credited to Gregory H. Fasullo, Iftekhar Hasan, Frank I. Menocal.
Application Number | 20210215367 17/215607 |
Document ID | / |
Family ID | 1000005482009 |
Filed Date | 2021-07-15 |
United States Patent
Application |
20210215367 |
Kind Code |
A1 |
Hasan; Iftekhar ; et
al. |
July 15, 2021 |
Method of Auto Association of HVAC Energy with Control Signal for
Self Diagnostics of the HVAC System
Abstract
A system and method are described for self-diagnosing heating,
ventilation and air conditioning (HVAC) systems. The system and
method correlate an HVAC control mode of a particular HVAC unit
with an energy usage for the particular HVAC unit in order to match
normal patterns in energy usage with the HVAC control mode. This
correlation allows the system and method to identify potential
problems with the particular HVAC unit based on deviations from
normal patterns.
Inventors: |
Hasan; Iftekhar;
(Richardson, TX) ; Fasullo; Gregory H.; (Dallas,
TX) ; Menocal; Frank I.; (Plano, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EnTouch Controls Inc. |
Richardson |
TX |
US |
|
|
Assignee: |
EnTouch Controls Inc.
Richardson
TX
|
Family ID: |
1000005482009 |
Appl. No.: |
17/215607 |
Filed: |
March 29, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14331978 |
Jul 15, 2014 |
10962248 |
|
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17215607 |
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61846469 |
Jul 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24F 11/30 20180101 |
International
Class: |
F24F 11/30 20060101
F24F011/30 |
Claims
1. A method for self-diagnosing heating, ventilation and air
conditioning (HVAC) systems comprising: correlating an HVAC control
mode of a particular HVAC unit with an energy usage for the
particular HVAC unit; matching normal patterns in energy usage with
the HVAC control mode; and identifying potential problems with the
particular HVAC unit based on deviations from normal patterns.
2. The method of claim 1 further comprising utilizing additional
parameters of the particular HVAC unit with the energy usage and
control mode to identify potential problems with the particular
HVAC unit.
3. The method of claim 2 wherein the additional parameter is sensor
air temperature.
4. The method of claim 1 further comprising reporting the potential
problems to a remote server.
5. The method of claim 1 further comprising reporting the potential
problems to a user.
6. The method of claim 1 wherein the particular HVAC unit is one of
a plurality of HVAC units.
7. The method of claim 1 wherein the energy usage is collected by
sensing current in a breaker panel associated with the particular
HVAC unit.
8. A system for self-diagnosing heating, ventilation and air
conditioning (HVAC) systems comprising: a microcontroller an HVAC
control module communicatively coupled to the microcontroller and
operable to provide control signals to an HVAC unit; an energy
usage collection interface communicatively coupled to the
microcontroller, the energy usage collection interface operable to
receive energy usage data from an energy meter installed at an
electrical distribution panel wherein the microcontroller is
operable to correlate an HVAC control mode from the HVAC control
module with an energy usage for the HVAC unit, and to match normal
patterns in energy usage with the HVAC control mode thereby
allowing the system to identify potential problems with the HVAC
unit based on deviations from normal patterns.
9. The system of claim 8 further comprising environmental sensors
communicatively coupled to the microcontroller, the environmental
sensors providing information to the microcontroller used in
determining the operation of the HVAC system.
10. The system of claim 9 wherein the microcontroller is operable
to utilize additional parameters of the HVAC unit collected from
the environmental sensors with the energy usage and control mode to
identify potential problems with the HVAC unit.
11. The system of claim 8 wherein the environmental sensors include
a temperature sensor.
12. The system of claim 8 further comprising a communications
interface to report the potential problems to a remote server.
13. The system of claim 8 wherein the particular HVAC unit is one
of a plurality of HVAC units.
14. The system of claim 8 wherein the energy usage is collected by
sensing current in a breaker panel associated with the particular
HVAC unit.
15. A method of correlating a control mode with energy usage for an
heating, ventilation and air conditioning (HVAC) unit, the method
comprising: assigning a true/false status for each control state of
the HVAC unit; assigning a true/false status for an energy usage of
the HVAC unit, wherein a true status corresponds to energy usage by
the HVAC unit; creating an array of states for each HVAC control
state; comparing the true/false status for energy usage for the
HVAC unit with the true/false status for each control state of the
HVAC unit; and pairing a highest correlated control state with the
energy true/false status for the HVAC unit.
Description
CROSS REFERENCE TO RELATED INFORMATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/331,978, filed Jul. 15, 2014, titled,
"Method of Auto Association of HVAC Energy with Control Signal for
Self Diagnostics of the HVAC System"; which claims the benefit of
U.S. Provisional Patent Application No. 61/846,469, filed Jul. 15,
2013, titled, "Method of Auto Association of HVAC Energy with
Control Signal for Self Diagnostics of the HVAC System", the
contents of which are hereby incorporated herein in its
entirety.
TECHNICAL FIELD
[0002] The present disclosure is directed to heating, ventilation
and air conditioning systems (HVAC), and more particularly to using
system control states, data, and energy usage to detect existing
and upcoming problems and failures in the system.
BACKGROUND OF THE INVENTION
[0003] Traditional thermostats monitor the temperature at location
inside a building and turn either a heating system or an air
conditioning system in response to changes in the monitored air
temperature. More recently, programmable thermostats have allowed
the owner or manager of a building to adjust the temperature set
point by day or week and time of day, allowing more control over
HVAC systems and reduced energy consumption from changing the set
point when the building is vacant or unused. New intelligent
thermostats are now entering the market that allow for remote
access and control. A significant variation in these remote
accessible thermostats is available in the market, which are solely
dedicated to control and access of HVAC system.
[0004] In addition to intelligent thermostats, many standalone
metering and sub metering devices are available to measure energy
at different load point and report it to the users. These meters
are all configured and scale the data at the point of measurement
so that they can measure individual load. For example, if a 3-phase
load is to be metered, the prior art would require this to be field
configured as such with proper hardware setup. Also, in the event
multiple load point is measured, they remain isolated measurements.
In some cases, these types of measurements are sufficient to
provide the useful information, however, the data is limited to
overall usage or the usage of specific loads without any ability to
group or characterize the loads.
[0005] While energy monitoring is becoming more common, no one has
combined the energy usage monitoring for HVAC loads with control
steps. Combining HVAC control with electrical energy usage data
gathering for any targeted load in the building allows the
association of the HVAC control mode (idle, cool, heat, fan etc.)
with the energy pattern of the corresponding HVAC. This correlation
can be very useful and can be utilized to trend and pattern match,
which can reveal any exception in the equipment behavior leading to
proactive maintenance alerts when combined with other measured
variables such as supply air temperature, to pin point exact
failure mechanism such as a broken fan belt or a frozen compressor
unit.
BRIEF SUMMARY OF THE INVENTION
[0006] In a preferred embodiment, a method is described for
self-diagnosing heating, ventilation and air conditioning (HVAC)
systems. The method correlates an HVAC control mode of a particular
HVAC unit with an energy usage for the particular HVAC unit in
order to match normal patterns in energy usage with the HVAC
control mode. This correlation allows the method to identify
potential problems with the particular HVAC unit based on
deviations from normal patterns.
[0007] In another preferred embodiment, a system for
self-diagnosing heating, ventilation and air conditioning (HVAC)
systems is described that includes a microcontroller having an HVAC
control module communicatively coupled to the microcontroller and
operable to provide control signals to an HVAC unit. An energy
usage collection interface communicatively coupled to the
microcontroller, the energy usage collection interface operable to
receive energy usage data from an energy meter installed at an
electrical distribution panel. The microcontroller is then operable
to correlate an HVAC control mode from the HVAC control module with
an energy usage for the HVAC unit, and to match normal patterns in
energy usage with the HVAC control mode thereby allowing the system
to identify potential problems with the HVAC unit based on
deviations from normal patterns.
[0008] The foregoing has outlined rather broadly the features and
technical advantages of the present invention in order that the
detailed description of the invention that follows may be better
understood. Additional features and advantages of the invention
will be described hereinafter which form the subject of the claims
of the invention. It should be appreciated by those skilled in the
art that the conception and specific embodiment disclosed may be
readily utilized as a basis for modifying or designing other
structures for carrying out the same purposes of the present
invention. It should also be realized by those skilled in the art
that such equivalent constructions do not depart from the spirit
and scope of the invention as set forth in the appended claims. The
novel features which are believed to be characteristic of the
invention, both as to its organization and method of operation,
together with further objects and advantages will be better
understood from the following description when considered in
connection with the accompanying figures. It is to be expressly
understood, however, that each of the figures is provided for the
purpose of illustration and description only and is not intended as
a definition of the limits of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] For a more complete understanding of the present invention,
reference is now made to the following descriptions taken in
conjunction with the accompanying drawings, in which:
[0010] FIG. 1 is a block diagram of a preferred embodiment of an
energy monitoring and metering system utilizing an intelligent
thermostat in accordance with the concepts described herein;
[0011] FIG. 2 is a set of graphs showing an example of a
correlation between control state and energy usage;
[0012] FIG. 3 is a flowchart of a preferred embodiment of a method
of correlating control state with energy usage;
[0013] FIGS. 4a, 4b, and 4c are a set of graphs showing examples of
a correlation between control state, and energy usage in a system
failure, including using another system state (such as sensor
temperature);
[0014] FIG. 5 is a block diagram of a preferred embodiment of a
controller as shown in FIG. 1; and
[0015] FIG. 6 is a block diagram of a preferred embodiment of an
energy meter as shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0016] As stated, the correlation between control mode and energy
pattern can be very useful and can be utilized to trend and pattern
match, which can reveal any exception in the equipment behavior
leading to proactive maintenance alerts. Even more can be learned
when the control state/energy correlation is combined with other
measured variables such as supply air temperature, to pin point
exact failure mechanism such as a broken fan belt or a frozen
compressor unit.
[0017] Referring now to FIG. 1, a preferred embodiment of a basic
monitoring and reporting system according to the concepts described
herein is shown. System 100 acts both to control the HVAC system in
premises 101 and to monitor, meter, analyze and report on the
energy usage at premises 101. Energy meters 102 and 103 are
installed preferably at a main breaker panel, but can also be
installed in sub-panels and distribution panels.
[0018] The energy meters 102 and 103 record raw measurements of
electrical usage and transmit that data to a main controller 106,
which can be either a zone controller, such as zone controller 104
or zone controller 105 or to a main controller 106. In preferred
embodiments, the energy meters use current transformers (CTs) to
measure the current in the monitored lines. The current is
preferably measured on the main electrical inputs to the breaker
panel and on all or any selected branch or load lines leaving the
panel. The reported energy usage from energy meter 102 and 103
includes the energy usage by HVAC system controlled by main
controller 106 and zone controllers 104 and 105. The association of
individual main 106 and zone controllers 104 and 105 control status
and corresponding energy usage signature is accomplished at remote
server 109 and data base as described later.
[0019] As described, energy meters 102 and 103 send the collected
data to a thermostat/controller. While the data can be sent using
hard wired connection without departing from the scope of the
invention described herein, in preferred embodiments wireless
protocols are used to transmit the data, eliminating the need to
run wires between devices or use other forms of wired
communications. Any appropriate wireless protocol may be used,
including WiFi, Zigby, Bluetooth, cellular, SMS or other wireless
protocol that has the appropriate specifications. In a house or
building that is small enough for a single thermostat, a single
controller, such as the main controller, can be used without losing
any functionality. In larger buildings, however, multiple zones may
be used to provide better control over the HVAC system. In
buildings using multiple zones, each zone can be equipped with its
own intelligent controller, shown here as zone controller 104 and
zone controller 105, according to the concepts described herein.
Each of those zone controllers can then be programmed to report to
a main controller 106, which serves as a primary collection and
communication hub to communicate with external server 109 and
database 110 of system 100.
[0020] Main controller 106 communicates with a remote monitoring
center 108 that houses an external server 109 and database 110
using network 107, which can be the Internet or any combination of
private or public networks. The system may also include more than
one remote monitoring center without departing from the scope of
the concepts described herein. Remote monitoring center 108 is
operable to collect, analyze, and provide access to the information
received from main controller and to allow the reprogramming of any
or all of the main controller or zone controllers at building 101.
Database 110 is used to store both the raw data from the building
controllers as well as any process data, configuration information,
or other information relevant to the system. External server 109 is
used to process the data and to provide a portal for remote access
into the data or an access point to remote control the building
controllers.
[0021] Remote user access 111 allows owners or managers of premises
101 to access and analyze the data collected from premises 101
using external server 109 and database 110. Users can look at past
data, real time data, reports and analyses generated from the data
and can also adjust operating parameters of the controllers and the
system configurations such as scaling factors used to interpret the
data collected by the energy meter 102 and 103. Remote monitoring
center 108 can be in contact with any number of premises and remote
user access 111 can access data and update operating configurations
for any number of premises under the user's control.
[0022] Referring now to FIG. 2, an example of a correlation between
HVAC signaling and energy usage is shown and described. An energy
management system, according to the concepts described herein,
combines HVAC control with electrical energy usage data gathering
for any targeted load in the building. The association of the HVAC
control mode (idle, cool, heat, fan etc.) and the energy pattern of
the corresponding HVAC is a very useful correlation that can be
utilized to trend and pattern match, which can reveal any exception
in the equipment behavior leading to proactive maintenance alerts
when combined with other measured variables such as supply air
temperature, to pin point exact failure mechanism such as a broken
fan belt or a frozen compressor unit.
[0023] During the configuration of the system, one of the
challenges is to make sure the control signal and the energy from
the HVAC are properly matched. This work is difficult due to poorly
marked electrical panels and in buildings with large number of HVAC
units. In a managed building, the number of monitored loads and
controlled HVAC units can be significantly high which results in
difficulty when finding a match between the control and energy
monitoring. It is desirable that the correlation is established
from data pattern matching. Such a correlation is shown with
reference to FIG. 2. FIG. 2 shows the state of an HVAC control
signal in graph 201. The signal, in the example of FIG. 2 is a
signal for fan and cool. The corresponding HVAC energy usage, shown
in graph 202, correlates well to the Fan/Cool signal in graph 201,
probably establishing a pattern match according to the concepts
described herein.
[0024] Accordingly the present invention provides for a method and
approach whereby data is collected to establish the relationship of
an HVAC unit with its energy data by pattern matching the control
signal for the said HVAC unit. Further, another method, an
embodiment of which is shown in FIG. 3, establishes a reference
correlation factor of the energy usage with respect to various
control stages. Identifying a deviation from the established
correlation factor provides for proactive health monitoring of the
HVAC unit. The correlation can be extended with other measured
variables to perform a detailed remote diagnosis of the HVAC unit
failure.
[0025] In a preferred embodiment of such a method 300, the steps to
auto assign the energy data to the respective HVAC unit can include
the following actions.
[0026] In time domain, collect control status from each HVAC
control unit for a given period (e.g. 24 hours). [0027] Assign a
TRUE or FALSE status for each control state of the HVAC control
units. The example of controls status are: (i) Cool: Idle, Stage1,
Stage2, Stage3; (ii) Heat: Idle, Stage 1, Stage 2, Stage3; or (iii)
Fan: Idle, On, shown in block 301; [0028] Assign a TRUE (when any
energy is reported) or FALSE (when no energy is reported) for each
branch energy (Energy Logic), shown in block 302; [0029] Logically
OR the state of the control signal and create a time domain array
of TRUE or FALSE for each HVAC control (Control Logic), shown in
block 303; [0030] Compare the Energy Logic of each branch of energy
with all of the Control Logic, shown in block 304; and [0031] The
highest correlated HVAC control and energy logic unit are paired
with each other shown in block 305.
[0032] Once the HVAC control unit and corresponding energy data is
properly matched, it is possible to establish more specific
reference data for trending and self diagnostics. The energy usage
threshold for different states of control can be trended for an
extended period of time e.g. 30 days. For example, when FAN state
is ON, we record a nominal 1 KW of energy usage. When both FAN and
STAGE1 COOL is active, we record a nominal 10 KW of energy usage.
From this trending, a nominal threshold of energy can be
established for future reference and a range of normal operating
deviation from these references can be defined. From the example
above, if the reported energy with both FAN and STAGE1 COOL active
is 1 KW, it is logical to assume that STAGE 1 compressor is not
activating. In other cases, this energy may be fluctuating between
7 KW and 10 KW, indicating a loose or wearing coupling mechanism.
Examples of such relationships are shown in FIG. 3.
[0033] Additional trouble shooting of a failed system is possible
by combining the energy and control signal information with a real
time reading of another parameter (e.g. supply air temperature).
Referring now to FIG. 4a, an example of system trouble shooting
using the concepts described herein is shown. If the control and
energy correlation is deemed normal, as shown by graphs 401 and
402, but the expected outcome (heating or cooling) is not matching,
shown by graph 403, the correlated data trend can proactively
detect a failure like low Freon in the system or a clogged filter.
In the first case, 404, the supply air will not cool while control
and energy pattern may not show a difference. In the event of a
frozen compressor, or clogged filter 405, the lack of air movement
will cause the sense temperature to drop close to freezing point.
Since this type of breakdown is usually gradual, an early trend in
either direction can be used as a preventive measure.
[0034] FIG. 4b shows an example of a mismatch between control
status 411 and energy usage signature 412. Control signal 416
indicates that the HVAC control is calling for cooling, however,
the low energy usage 415 indicates that the HVAC system is faulty.
This could be caused by a failed contactor, broken belt in the HVAC
unit, or other similar cause. The rising temperature sensor 414 in
air temperature graph 413 confirms the inadequacy of the HVAC
system.
[0035] FIG. 4c shows another example of system failure indicated by
the correlations described herein. HVAC control signal 426 in
control signal graph 421 indicates that the cooling need is
complete at approximately 9:00 pm and the signal call is to
terminate cooling. The energy signature 425 in energy control graph
422 shows that the energy usage by the HVAC system continues at the
same level despite the change in control state. This could indicate
a faulty contactor in the HVAC system. The continuing drop in air
temperature shown in air temperature graph 423 confirms a
problem.
[0036] Referring now to FIG. 5, an embodiment of a controller, such
as main controller 106 or zone controllers 104 or 105 is shown.
Controller 500 includes main microcontroller 501, which is operable
to execute the programming of controller 500. Main microcontroller
501 may include on board memory to store configuration and
programming information or may use some portion of memory 105. Main
microcontroller 501 controls the display and graphical user
interface 502, through which users may directly interact with the
controller to view current status or to change the programming or
configuration information. Main microcontroller 501 also controls
the remote access port 507, which provides for communications with
external networks such as WiFi, LAN, or GSM networks.
[0037] Communication and sensor microcontroller 503 is also in
communication with main microcontroller 501 and provides the
interface between the main microcontroller 501 and any remote HVAC
sensors 508. Communication and sensor microcontroller 503 also
interfaces with the wireless radio 504, which communicates with the
energy meters in the distribution or breaker panel. Communication
and sensor microcontroller 503 and main microcontroller 501 also
interface with the HVAC controller 506, which is used to control
the HVAC system hardware. As shown in FIG. 1, the controller 500
can also communicate with a remote server or user access interface.
Using these communication paths, the controller can report
identified problems to a data collection system or a designated
user for the system.
[0038] Referring now to FIG. 6, an embodiment of an energy meter
according to the concepts described herein is shown. Energy meter
600 includes microcontroller 601 which acts to execute the
programming of energy meter 600. Microcontroller 601 receives
inputs from 3-phase power meter 603 and current sense circuitry
602. The DSP based 3-phase power meter 603 measures the power usage
at the main 3-phase power inputs to the breaker panel and reports
that information to the microcontroller 601. Current sense
circuitry 602 is connected to current transformers on any or all of
the branch load circuits fed by the breaker panel and measures the
current draw of those loads. The loads can be any type of load,
such as single phase, 3-phase, etc. The load data is also reported
to the microcontroller 601. Microcontroller 601 then reports the
collected data in a raw, un-scaled format to a main controller or
zone controller over wireless radio 604.
[0039] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the invention as defined by the
appended claims. Moreover, the scope of the present application is
not intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure of the present invention, processes, machines,
manufacture, compositions of matter, means, methods, or steps,
presently existing or later to be developed that perform
substantially the same function or achieve substantially the same
result as the corresponding embodiments described herein may be
utilized according to the present invention. Accordingly, the
appended claims are intended to include within their scope such
processes, machines, manufacture, compositions of matter, means,
methods, or steps.
* * * * *