US20190374894A1 - Systems and methods of predicting life of a filter in an hvac system - Google Patents
Systems and methods of predicting life of a filter in an hvac system Download PDFInfo
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- US20190374894A1 US20190374894A1 US16/004,129 US201816004129A US2019374894A1 US 20190374894 A1 US20190374894 A1 US 20190374894A1 US 201816004129 A US201816004129 A US 201816004129A US 2019374894 A1 US2019374894 A1 US 2019374894A1
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- Prior art keywords
- static pressure
- air
- hvac system
- filter
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
- F24F11/32—Responding to malfunctions or emergencies
- F24F11/39—Monitoring filter performance
-
- F24F3/1603—
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F8/00—Treatment, e.g. purification, of air supplied to human living or working spaces otherwise than by heating, cooling, humidifying or drying
- F24F8/10—Treatment, e.g. purification, of air supplied to human living or working spaces otherwise than by heating, cooling, humidifying or drying by separation, e.g. by filtering
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/18—Status alarms
- G08B21/182—Level alarms, e.g. alarms responsive to variables exceeding a threshold
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2273/00—Operation of filters specially adapted for separating dispersed particles from gases or vapours
- B01D2273/18—Testing of filters, filter elements, sealings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2279/00—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses
- B01D2279/50—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses for air conditioning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/0084—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours provided with safety means
- B01D46/0086—Filter condition indicators
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/20—Pc systems
- G05B2219/26—Pc applications
- G05B2219/2614—HVAC, heating, ventillation, climate control
Definitions
- HVAC heating, ventilation, and air conditioning
- HVAC Heating, ventilation, and air conditioning
- an air blower is used to pull air from the enclosed space into the HVAC system through ducts and push the air back into the enclosed space through additional ducts after conditioning the air (e.g., heating, cooling or dehumidifying the air).
- HVAC systems such as residential and commercial, may be used to provide conditioned air for enclosed spaces.
- Each HVAC system typically includes a HVAC controller that directs the operation of the HVAC system.
- the HVAC controller can direct the operation of a conditioning unit, such as an air conditioner or a heater, to control the temperature of the enclosed space.
- HVAC systems may also filter the air.
- HVAC systems employ one or more air filters that capture airborne pollutants (e.g., dust, debris).
- a heating, ventilation, and air conditioning (“HVAC”) system includes at least one blower, an air filter, at least one sensor, and at least one controller.
- the at least one blower is operable to move air
- the air filter is configured to entrap airborne pollutants
- the at least one sensor is configured to sense a static pressure of the HVAC system.
- the at least one controller is operable to initiate a filter calibration procedure whereby the static pressure is measured at a plurality of predetermined points, each predetermined point being a specified flowrate of air moved by the at least one blower.
- the at least one controller is further operable to curve fit a first line based on the static pressure measurements and the corresponding flowrates of air, the first line indicating values of static pressure and corresponding flowrates of air of a clean filter, and generate a second line based on the first line, the second line indicating values of static pressure and corresponding flowrates of air of a dirty filter.
- the at least one controller is further operable to determine a first static pressure measurement of the HVAC system in response to determining that a first flowrate of air has been moved by the at least one blower and compare the first static pressure value to a predicted static pressure value of the second line, the predicted static pressure value corresponding to the first flowrate of air.
- the at least one controller is further operable to determine that the air filter has no more usable life in response to determining that the first static pressure value is greater than the predicted static pressure value.
- a method includes initiating, by a controller of a heating, ventilation, and air conditioning (“HVAC”) system, a filter calibration procedure whereby static pressure of the HVAC system is measured at a plurality of predetermined points, each predetermined point being a specified flowrate of air moved by at least one blower of the HVAC system, the static pressure measured by at least one sensor of the HVAC system.
- the method further includes curve fitting, by the controller, a first line based on the static pressure measurements and the corresponding flowrates of air, the first line indicating values of static pressure and corresponding flowrates of air of a clean filter, and generating a second line based on the first line, the second line indicating values of static pressure and corresponding flowrates of air of a dirty filter.
- the method further includes determining a first static pressure measurement of the HVAC system in response to determining that a first flowrate of air has been moved by the at least one blower and comparing the first static pressure value to a predicted static pressure value of the second line, the predicted static pressure value corresponding to the first flowrate of air.
- the method further includes determining that an air filter of the HVAC system has no more usable life in response to determining that the first static pressure value is greater than the predicted static pressure value.
- a controller for a heating, ventilation, and air conditioning (“HVAC”) system is operable to initiate a filter calibration procedure whereby static pressure of the HVAC system is measured at a plurality of predetermined points, each predetermined point being a specified flowrate of air moved by at least one blower of the HVAC system, the static pressure measured by at least one sensor of the HVAC system.
- the controller is further operable to curve fit a first line based on the static pressure measurements and the corresponding flowrates of air, the first line indicating values of static pressure and corresponding flowrates of air of a clean filter, and generate a second line based on the first line, the second line indicating values of static pressure and corresponding flowrates of air of a dirty filter.
- the controller is further operable to determine a first static pressure measurement of the HVAC system in response to determining that a first flowrate of air has been moved by the at least one blower and compare the first static pressure value to a predicted static pressure value of the second line, the predicted static pressure value corresponding to the first flowrate of air.
- the controller is further operable to determine that an air filter of the HVAC system has no more usable life in response to determining that the first static pressure value is greater than the predicted static pressure value
- Certain embodiments may provide one or more technical advantages. For example, an embodiment of the present disclosure may result in maximizing the usable life of an air filter. As another example, an embodiment of the present invention notifies an operator of the HVAC system when the air filter has no remaining usable life. As such, the operator may be prompted to replace the dirty air filter with a clean one thereby increasing the efficiency of operating the HVAC system and/or providing cleaner air to the enclosed space. Certain embodiments may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.
- FIG. 1 illustrates an example of an air handling unit of a heating, ventilation, and air conditioning (“HVAC”) system, according to certain embodiments.
- HVAC heating, ventilation, and air conditioning
- FIG. 2 is a flow chart illustrating a method of operation for the HVAC system of FIG. 1 , according to certain embodiments.
- FIG. 3 is an example graph illustrating steps of the method of FIG. 2 , according to certain embodiments.
- FIG. 4 is an example graph illustrating additional steps of the method of FIG. 2 , according to certain embodiments.
- FIG. 5 illustrates an example of a controller for the refrigeration system of FIG. 1 , according to certain embodiments.
- FIGS. 1 through 5 of the drawings like numerals being used for like and corresponding parts of the various drawings.
- Air filters generally filter pollutants such as dust, allergens, and dander from the air.
- pollutants such as dust, allergens, and dander from the air.
- air filters are installed within air vents of an enclosed space and entrap pollutants as air flows through the air filter. Over time, the air filter becomes soiled with pollutants, resulting in an increase in the static pressure of the HVAC system and reduced efficiency of both the HVAC system and the air filter. Accordingly, an air filter has a usable life that, upon expiration, causes a number of inefficiencies.
- Conventional wisdom calls for residential air filters to be replaced every three to twelve months (depending on the filter type and recommendation from the filter manufacturer).
- the rate at which an air filter becomes soiled differs based on a number of factors such as the number of occupants/pets within an enclosed space and the level of pollution and/or construction in an environment of the enclosed space.
- some air filters may need to be replaced more often than manufacturers recommend and some air filters may need to be replaced less often than the manufacturers recommend.
- some air filters may be replaced before they actually need be and others may be replaced later than they should be replaced.
- HVAC systems do not have the intelligence to alert an operator to replace an air filter. Instead, operators themselves must remember to change the air filter.
- the alert is generated based on a timer (e.g., such as a 3-month time and/or a blower run time timer). Because such alerts do not analyze whether the air filter has remaining usable life, these solutions may cause waste (e.g., by not maximizing the usable life of a filter), reduce the quality of the air of the enclosed space, and/or the efficiency of the HVAC system.
- the present disclosure recognizes an HVAC system provided with the operational intelligence to determine whether an air filter has usable life remaining.
- the HVAC system determines the usable life of an air filter by monitoring the static pressure of the HVAC system.
- the logic to perform such intelligent operation is stored to one or more storage devices of controller 140 .
- being able to determine the usable life of an air filter is associated with a variety of benefits including less waste, filtration maximization, improved air quality, and increased efficiency of operating an HVAC system.
- FIG. 1 illustrates an example of an HVAC system 100 .
- HVAC system 100 includes at least one blower 110 , an air filter 120 , at least one sensor 130 , and at least one controller 140 .
- HVAC system 100 may also include a return air duct 150 , an evaporator coil 160 , refrigerant tubing 170 , and an air supply duct 180 .
- air is sucked out an enclosed space 105 through return air duct 150 and is filtered by air filter 120 .
- the filtered air is generally pushed by blower 110 across conventional conditioning elements (e.g., evaporator coil 160 and refrigerant tubing 170 ) before it is circulated back into enclosed space 105 via air supply duct 180 .
- conventional conditioning elements e.g., evaporator coil 160 and refrigerant tubing 170
- Blower 110 is configured to move air through HVAC system 100 (e.g., via return air duct 150 and air supply duct 180 ).
- blower 110 is driven by a motor. Blower 110 may be operated at one or more speeds. This disclosure recognizes that operating blower 110 at a higher speed provides an increased air flow rate relative to operating blower 110 at a lower speed.
- controller 110 controls the operation of blower 110 .
- controller 110 may instruct blower 110 to power on, power off, increase speed, and/or decrease speed.
- controller 110 may instruct blower 110 to power on (from an off mode) and operate at a speed corresponding to an air flow rate of 400 cubic feet per minute (“CFM”).
- Controller 110 may further instruct blower 110 to increase speed (e.g., operate at a speed corresponding to an air flow rate of 600 CFM) and/or decrease speed (e.g., operate at a speed corresponding to an air flow rate of 200 CFM).
- Air filter 120 is configured to increase the quality of the air circulating in HVAC system 100 by entrapping pollutants.
- Pollutants may include particulates such as dust, pollen, allergens (e.g., dust mite and cockroach), mold, and dander. Pollutants may also include gases and odors such as gas from a stovetop, tobacco smoke, paint, adhesives, and/or cleaning products.
- gases and odors such as gas from a stovetop, tobacco smoke, paint, adhesives, and/or cleaning products.
- air filter 120 becomes soiled and has no usable life left in it. This disclosure recognizes that an air filter having no usable life has reduced effectiveness at improving air quality relative to an air filter having usable life.
- blower 110 may require 0.925 KW of energy to move 1365 CFM when an air filter having usable life is installed within HVAC system 100 but requires 1.07 KW of energy to move the same amount of air when an air filter having no usable life is installed within HVAC system 100 .
- air filters are cleaned and/or replaced when they have no usable life left.
- HVAC system 100 may also include one or more sensors 130 .
- Sensors 130 may be configured to sense information about HVAC system 100 , about enclosed space 105 , and/or about components of HVAC system 100 .
- HVAC system 100 may include a sensor 130 configured to sense data about a static pressure of HVAC system 100 .
- one or more sensors may be configured to sense data related to a temperature of enclosed space 105 .
- one or more sensors may be configured to sense data regarding a temperature and/or pressure leaving a condenser of HVAC system 100 .
- this disclosure describes specific types of sensors, HVAC system 100 may include any other type and any suitable number of sensors 130 .
- HVAC system 100 includes at least one controller 140 that directs the operations of HVAC system 100 .
- Controller 140 may be communicably coupled to one or more components of HVAC system 100 .
- controller 140 may be configured to receive data sensed by sensors 130 .
- controller 140 may be configured to provide instructions to one or more components of refrigeration system 100 (e.g., blower 110 ).
- Controller 140 may be configured to provide instructions via any appropriate communications link (e.g., wired or wireless) or analog control signal.
- An example of controller 140 is further described below with respect to FIG. 5 .
- controller 140 includes or is a computer system.
- controller 140 is located within a wall-mounted thermostat in enclosed space 105 .
- Operation of HVAC system 100 may be controlled by an operator who programs HVAC system 100 using one or more buttons 145 on the thermostat.
- HVAC system 100 may be programmed to initiate a cooling cycle in response to determining user input via buttons 145 .
- HVAC system 100 may be programmed to initiate a filter calibration procedure in response to determining user input via buttons 145 .
- FIG. 2 illustrates a method 200 of operation for HVAC system 100 .
- the method 200 may be implemented by a controller of dehumidification system 200 (e.g., controller 140 of FIG. 1 ).
- controller 140 e.g., controller 140 of FIG. 1
- method 200 may be stored on a computer readable medium, such as a memory of controller 140 (e.g., memory 520 of FIG. 5 ), as a series of operating instructions that direct the operation of a processor (e.g., processor 530 of FIG. 5 ).
- Method 200 may be associated with efficiency benefits such as reduced power consumption relative to conventional methods of operating HVAC system 100 .
- the method 200 begins in step 205 and continues to step 210 .
- controller 140 initiates a filter calibration procedure.
- the filter calibration procedure includes measuring the static pressure of HVAC system 100 at a plurality of predetermined air flowrates.
- filter calibration procedure may provide for HVAC system 100 to take static pressure measurements at 1333.33 CFM, 1666.67 CFM, and 2000 CFM from a baseline.
- a “baseline” may refer to a flowrate of air from which other flowrates are determined (e.g., 1,333.33 CFM is 1,333.33 from a baseline 0 CFM).
- FIG. 3 illustrates examples of static pressure measurements taken at a plurality of air flowrates (e.g., see SP 1 , SP 2 , and SP 3 of FIG. 3 ).
- a baseline may be set as soon as the filter calibration procedure is initiated.
- the static pressure of HVAC system 100 is measured via sensors 130 .
- the filter calibration procedure may be initiated in any suitable way including, but not limited to, installation of air filter 120 in an air duct of HVAC system 100 and user input (e.g., depression of button 245 on a thermostat). After completing the filter calibration procedure, the method 200 may proceed to step 215 .
- controller 140 curve fits a first line based on the measurements taken during the filter calibration procedure.
- controller may generate an equation based on three or more sensed static pressure values measured at different air flowrates (e.g., 1,333.33 CFM, 1,666.67 CFM, and 2000.00 CFM).
- An example of such a curved-fit line is line 310 (indicated in dotted line) of FIG. 3 .
- line 310 is curve fit based on static pressure (“SP”) points SP 1 , SP 2 , and SP 3 .
- Points along first line 310 may represent values of a “clean” filter at a plurality of static pressure measurements and corresponding air flowrates.
- first line 310 may refer to first line 310 as a “clean filter” line, this disclosure recognizes that air filter 120 may be partially or fully soiled when installed.
- the method 200 proceeds to a step 220 after curve fitting first line 310 .
- controller 140 generates a second line based on points of the first line.
- the points along the second line are scaled from points along the first line using fan laws, a predetermined relationship or a system-derived relationship.
- An example of such scaled points are the three predicted points “PP” of FIG. 3 (see PP 1 , PP 2 , and PP 3 of FIG. 3 ).
- the second line may be curve fit from the predicted points.
- An example of the generated second line is second line 320 (illustrated in dashed line) of FIG. 2 .
- Points along second line 320 may represent predicted values of a “dirty” filter at a plurality of static pressure measurements and corresponding air flowrates.
- Second line 320 may be represented by an equation. After generating the second line, the method 200 may proceed to step 225 .
- controller 140 determines a first static pressure measurement of HVAC system 100 .
- the first static pressure measurement may be taken at a predetermined flowrate of air.
- the first static pressure measurement may be determined at 1500 CFM from the baseline.
- the first static pressure measurement is sensed by sensor 130 .
- the first static pressure measurement is calculated based on other values sensed by sensors 130 (e.g., 81.25% of max CFM of the HVAC unit). After determining the first static pressure measurement, the method 200 may proceed to step 230 .
- controller 140 compares the first static pressure measurement to a predicted static pressure value.
- controller 140 compares the first static pressure measurement to the predicted static pressure value at the predetermined flowrate of air. For example, if the first static pressure measurement was taken at 1500 CFM from the baseline, controller 140 compares the first static pressure measurement to a predicted static pressure value at 1500 CFM. Taking the measured pressures and predicted pressures of FIG. 4 as an example, controller 140 may determine that at 1500 CFM, the first static pressure measurement of HVAC system 100 is 0.18 inches of water (see MP 1 of FIG. 4 ) and the predicted pressure of second line (dirty filter line) 320 is about 0.22 inches of water. As such, controller 140 may compare 0.18 inches of water (MP 1 ) to 0.22 inches of water (PP not illustrated ).
- controller 140 determines whether the first static pressure measurement is greater than the predicted static pressure measurement. Taking the above example, controller 140 determines whether 0.18 inches of water (MP 1 ) is greater than 0.22 inches of water (PP not illustrated ). If controller 140 determines that the first static pressure measurement is greater than the predicted static pressure measurement, the method 200 may proceed to a step 240 . If controller 140 instead determines that the first static pressure measurement is equal to or less than the predicted static pressure measurement, the method 200 may proceed to step 230 .
- MP 1 0.18 inches of water
- PP not illustrated 0.22 inches of water
- controller 140 determines that air filter 120 has no more usable life. In some instances, the method 200 proceeds to step 245 in response to making such determination. At step 245 , controller 140 generates an alert.
- the alert may be a visual alert such as a text-based alert for display on a thermostat and/or a user device (e.g., a cell phone).
- the alert may be an audio alert (e.g., a beeping sound) from a thermostat and/or user device.
- this disclosure has described particular types of alerts, this disclosure recognizes any suitable alert.
- an operator of HVAC system 100 takes action in response to receiving the alert generated at step 245 .
- an operator of HVAC system 100 may replace and/or clean air filter 120 in response to receiving the alert generated at step 245 .
- an operator of HVAC system may depress button 245 on wall-mounted thermostat in order to re-initiate the filter calibration procedure.
- the method 200 proceeds to end step 250 after generating the alert.
- controller 120 performs one or more additional steps. For example, controller may perform one or more additional steps instead of proceeding to end step 250 . In such an example, controller 120 may continue to monitor the static pressure of HVAC system 100 after determining at step 235 that the first static pressure measurement is equal to or less than the predicted static pressure measurement. In some embodiments, controller 140 may perform further comparison and determination steps. For example, controller 150 may determine a static pressure of HVAC system 140 at 1800 CFM and compare the static pressure to a predicted value of static pressure at 1800 CFM. Taking the values of FIG. 4 as an example, controller may determine that the static pressure of HVAC system 100 at 1800 CFM is about 0.23 inches of water (see MP 2 of FIG.
- Controller 140 may further determine that the measured value of static pressure (about 0.23 inches of water) is less than the predicted value of static pressure at 1800 CFM (about 0.31 inches of water). Controller 140 may continue to perform such determination and comparison steps as necessary. For example, controller 140 may continue to perform these determination and comparison steps until controller 140 determines that a measured static pressure at CFM X is greater than a predicted static pressure at CFM X .
- An example of such determination is depicted in FIG. 4 when the measured static pressure at 2200 CFM (see MP 6 having a static pressure of about 0.52 inches of water) exceeds the corresponding predicted static pressure (about 0.485 inches of water) at 2200 CFM.
- this disclosure describes and depicts detecting a static pressure above a predicted pressure, this disclosure also recognizes detecting whether the static pressure of the HVAC system is stagnant or declining. In some cases, stagnant or declining measurements of static pressure of HVAC system 100 may indicate that an air filter 120 having no usable life is installed within HVAC system 100 . This may occur when, for example, an operator attempts to fool HVAC system 100 by initiating the calibration procedure without replacing/cleaning air filter 120 .
- HVAC system 100 may receive substantially similar static pressure measurements (e.g., +/ ⁇ 10% of a first measured static pressure) at a plurality of air flowrates (e.g., 1,333.33 CFM, 1,666.67 CFM, 2000.00 CFM) during the filter calibration procedure, and then continue to receive substantially similar static pressure measurements after completing the filter calibration procedure.
- the HVAC system 100 may be further programmed to generate an alert in response to determining that the static pressure of the HVAC system is not increasing at an expected rate (e.g., determining that the static pressure of the HVAC system is +/ ⁇ 10% of 0.45 inches of water when measured at 1200 CFM, 1600 CFM, 2000 CFM, and 2400 CFM).
- FIGS. 3 and 4 are graphs illustrating one or more steps of method 200 .
- FIG. 3 illustrates static pressure measurements taken during the filter calibration procedure described above in reference to step 210 , curve-fitting a first line from the static pressure measurements taken during the filter calibration procedure as described above in reference to step 220 , and generating a second line based on the first line as described above in reference to step 230 .
- three static pressure measurements are taken at three different flowrates of air: SP 1 , SP 2 , and SP 3 .
- SP 1 is about 0.15 inches of water at 1,333.33 CFM
- SP 2 is about 0.21 inches of water at 1,666.67 CFM
- SP 3 is about 0.29 inches of water at 2000.00 CFM.
- First line 310 of FIG. 3 is determined based on the static pressure measurements taken during the filter calibration procedure.
- line 310 may represent values of a “clean” filter at a plurality of static pressure measurements and corresponding air flowrates.
- FIG. 3 also illustrates a plurality of predicted static pressures: PP 1 , PP 2 , and PP 3 . As illustrated, PP 1 is about 0.19 inches of water at 1,333.33 CFM, PP 2 is about 0.28 inches of water at 1,666.67 CFM, and PP 3 is about 0.39 inches of water at 2000.00 CFM.
- the values of PP 1 , PP 2 , and PP 3 are scaled from the values of SP 1 , SP 2 , and SP 3 , respectively, using fan laws. In some embodiments, the values of PP 1 , PP 2 , and PP 3 are used to generate second line 320 .
- FIG. 4 illustrates first line 310 and second line 320 of FIG. 3 in addition to illustrating a plurality of static pressure measurements taken at predetermined flowrates of air (see MP 1 , MP 2 , MP 3 , MP 4 , MP 5 , and MP 6 ).
- MP 1 is about 0.18 inches of water at 1500.00 CFM
- MP 2 is about 0.23 inches of water at 1800.00 CFM
- MP 3 is about 0.275 inches of water at 1900.00 CFM
- MP 4 is about 0.35 inches of water at 2000 CFM
- MP 5 is about 0.42 inches of water at 2100 CFM
- MP 6 is about 0.52 inches of water at 2200 CFM.
- controller 140 determines the static pressure of HVAC system 100 as blower 110 moves predetermined flowrates of air. These values may then be compared against either values of first line 310 and/or values of second line 320 to determine whether air filter 120 has remaining usable life.
- controller 140 can predict how dirty air filter 120 is. This prediction is referred to herein as a percent dirty (or soilage percentage) of air filter 120 . In some embodiments, controller 140 determines percent dirty using the following formula:
- controller 140 determines percent dirty as above but substitutes MP avg for MP X , wherein MP avg is equal to an average of samples in a data set.
- Controller 140 may be further programmed to generate one or more additional alerts based on a soilage percentage of air filter 120 .
- controller 140 may be configured to generate an alert in response to determining that air filter 120 has a dirtiness percentage of 10% or less.
- this disclosure describes a specific alert threshold, this disclosure recognizes that this alert threshold may be set at any suitable percentage, and in some embodiments, may be set by an operator of HVAC system 100 .
- FIG. 5 illustrates an example controller 140 of HVAC system 100 , according to certain embodiments of the present disclosure.
- Controller 140 may comprise one or more interfaces 510 , memory 520 , and one or more processors 530 .
- Interface 510 receives input (e.g., sensor data, user input), sends output (e.g., instructions), processes the input and/or output, and/or performs other suitable operation.
- Interface 510 may comprise hardware and/or software.
- Processor 530 may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or all of the described functions of controller 140 .
- processor 530 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), and/or other logic.
- CPUs central processing units
- microprocessors one or more applications
- ASICs application specific integrated circuits
- FPGAs field programmable gate arrays
- Memory (or memory unit) 520 stores information.
- Memory 520 may comprise one or more non-transitory, tangible, computer-readable, and/or computer-executable storage media.
- Examples of memory 520 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), database and/or network storage (for example, a server), and/or other computer-readable medium.
- RAM Random Access Memory
- ROM Read Only Memory
- mass storage media for example, a hard disk
- removable storage media for example, a Compact Disk (CD) or a Digital Video Disk (DVD)
- database and/or network storage for example, a server
- network storage for example, a server
- HVAC system may include any suitable number of compressors, condensers, condenser fans, evaporators, valves, sensors, controllers, and so on, as performance demands dictate.
- HVAC system contemplated by this disclosure can include other components that are not illustrated but are typically included with HVAC systems.
- operations of the systems and apparatuses may be performed using any suitable logic comprising software, hardware, and/or other logic.
- ach refers to each member of a set or each member of a subset of a set.
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Abstract
Description
- This disclosure relates generally to filters of a heating, ventilation, and air conditioning (“HVAC”) system. More specifically, this disclosure relates to a systems and methods of predicting the life of a filter of an HVAC system.
- Heating, ventilation, and air conditioning (“HVAC”) systems can be used to regulate the environment within an enclosed space. Typically, an air blower is used to pull air from the enclosed space into the HVAC system through ducts and push the air back into the enclosed space through additional ducts after conditioning the air (e.g., heating, cooling or dehumidifying the air). Various types of HVAC systems, such as residential and commercial, may be used to provide conditioned air for enclosed spaces.
- Each HVAC system typically includes a HVAC controller that directs the operation of the HVAC system. The HVAC controller can direct the operation of a conditioning unit, such as an air conditioner or a heater, to control the temperature of the enclosed space. In addition to conditioning the air, HVAC systems may also filter the air. Typically, HVAC systems employ one or more air filters that capture airborne pollutants (e.g., dust, debris).
- According to one embodiment, a heating, ventilation, and air conditioning (“HVAC”) system includes at least one blower, an air filter, at least one sensor, and at least one controller. The at least one blower is operable to move air, the air filter is configured to entrap airborne pollutants, and the at least one sensor is configured to sense a static pressure of the HVAC system. The at least one controller is operable to initiate a filter calibration procedure whereby the static pressure is measured at a plurality of predetermined points, each predetermined point being a specified flowrate of air moved by the at least one blower. The at least one controller is further operable to curve fit a first line based on the static pressure measurements and the corresponding flowrates of air, the first line indicating values of static pressure and corresponding flowrates of air of a clean filter, and generate a second line based on the first line, the second line indicating values of static pressure and corresponding flowrates of air of a dirty filter. The at least one controller is further operable to determine a first static pressure measurement of the HVAC system in response to determining that a first flowrate of air has been moved by the at least one blower and compare the first static pressure value to a predicted static pressure value of the second line, the predicted static pressure value corresponding to the first flowrate of air. The at least one controller is further operable to determine that the air filter has no more usable life in response to determining that the first static pressure value is greater than the predicted static pressure value.
- According to another embodiment, a method includes initiating, by a controller of a heating, ventilation, and air conditioning (“HVAC”) system, a filter calibration procedure whereby static pressure of the HVAC system is measured at a plurality of predetermined points, each predetermined point being a specified flowrate of air moved by at least one blower of the HVAC system, the static pressure measured by at least one sensor of the HVAC system. The method further includes curve fitting, by the controller, a first line based on the static pressure measurements and the corresponding flowrates of air, the first line indicating values of static pressure and corresponding flowrates of air of a clean filter, and generating a second line based on the first line, the second line indicating values of static pressure and corresponding flowrates of air of a dirty filter. The method further includes determining a first static pressure measurement of the HVAC system in response to determining that a first flowrate of air has been moved by the at least one blower and comparing the first static pressure value to a predicted static pressure value of the second line, the predicted static pressure value corresponding to the first flowrate of air. The method further includes determining that an air filter of the HVAC system has no more usable life in response to determining that the first static pressure value is greater than the predicted static pressure value.
- According to yet another embodiment, a controller for a heating, ventilation, and air conditioning (“HVAC”) system is operable to initiate a filter calibration procedure whereby static pressure of the HVAC system is measured at a plurality of predetermined points, each predetermined point being a specified flowrate of air moved by at least one blower of the HVAC system, the static pressure measured by at least one sensor of the HVAC system. The controller is further operable to curve fit a first line based on the static pressure measurements and the corresponding flowrates of air, the first line indicating values of static pressure and corresponding flowrates of air of a clean filter, and generate a second line based on the first line, the second line indicating values of static pressure and corresponding flowrates of air of a dirty filter. The controller is further operable to determine a first static pressure measurement of the HVAC system in response to determining that a first flowrate of air has been moved by the at least one blower and compare the first static pressure value to a predicted static pressure value of the second line, the predicted static pressure value corresponding to the first flowrate of air. The controller is further operable to determine that an air filter of the HVAC system has no more usable life in response to determining that the first static pressure value is greater than the predicted static pressure value,
- Certain embodiments may provide one or more technical advantages. For example, an embodiment of the present disclosure may result in maximizing the usable life of an air filter. As another example, an embodiment of the present invention notifies an operator of the HVAC system when the air filter has no remaining usable life. As such, the operator may be prompted to replace the dirty air filter with a clean one thereby increasing the efficiency of operating the HVAC system and/or providing cleaner air to the enclosed space. Certain embodiments may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.
- For a more complete understanding of the present disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
-
FIG. 1 illustrates an example of an air handling unit of a heating, ventilation, and air conditioning (“HVAC”) system, according to certain embodiments. -
FIG. 2 is a flow chart illustrating a method of operation for the HVAC system ofFIG. 1 , according to certain embodiments. -
FIG. 3 is an example graph illustrating steps of the method ofFIG. 2 , according to certain embodiments. -
FIG. 4 is an example graph illustrating additional steps of the method ofFIG. 2 , according to certain embodiments. -
FIG. 5 illustrates an example of a controller for the refrigeration system ofFIG. 1 , according to certain embodiments. - Embodiments of the present disclosure and its advantages are best understood by referring to
FIGS. 1 through 5 of the drawings, like numerals being used for like and corresponding parts of the various drawings. - Air filters generally filter pollutants such as dust, allergens, and dander from the air. Typically, air filters are installed within air vents of an enclosed space and entrap pollutants as air flows through the air filter. Over time, the air filter becomes soiled with pollutants, resulting in an increase in the static pressure of the HVAC system and reduced efficiency of both the HVAC system and the air filter. Accordingly, an air filter has a usable life that, upon expiration, causes a number of inefficiencies. Conventional wisdom calls for residential air filters to be replaced every three to twelve months (depending on the filter type and recommendation from the filter manufacturer). However, the rate at which an air filter becomes soiled differs based on a number of factors such as the number of occupants/pets within an enclosed space and the level of pollution and/or construction in an environment of the enclosed space. Thus, some air filters may need to be replaced more often than manufacturers recommend and some air filters may need to be replaced less often than the manufacturers recommend. As a result, some air filters may be replaced before they actually need be and others may be replaced later than they should be replaced.
- Most HVAC systems do not have the intelligence to alert an operator to replace an air filter. Instead, operators themselves must remember to change the air filter. For HVAC systems that are programmed to provide such an alert, the alert is generated based on a timer (e.g., such as a 3-month time and/or a blower run time timer). Because such alerts do not analyze whether the air filter has remaining usable life, these solutions may cause waste (e.g., by not maximizing the usable life of a filter), reduce the quality of the air of the enclosed space, and/or the efficiency of the HVAC system.
- The present disclosure recognizes an HVAC system provided with the operational intelligence to determine whether an air filter has usable life remaining. In certain embodiments, the HVAC system determines the usable life of an air filter by monitoring the static pressure of the HVAC system. In some embodiments, the logic to perform such intelligent operation is stored to one or more storage devices of
controller 140. As provided above, being able to determine the usable life of an air filter is associated with a variety of benefits including less waste, filtration maximization, improved air quality, and increased efficiency of operating an HVAC system. -
FIG. 1 illustrates an example of anHVAC system 100.HVAC system 100 includes at least oneblower 110, anair filter 120, at least onesensor 130, and at least onecontroller 140. As depicted inFIG. 1 ,HVAC system 100 may also include areturn air duct 150, anevaporator coil 160,refrigerant tubing 170, and anair supply duct 180. In some embodiments, air is sucked out an enclosedspace 105 throughreturn air duct 150 and is filtered byair filter 120. The filtered air is generally pushed byblower 110 across conventional conditioning elements (e.g.,evaporator coil 160 and refrigerant tubing 170) before it is circulated back into enclosedspace 105 viaair supply duct 180. - Blower 110 is configured to move air through HVAC system 100 (e.g., via
return air duct 150 and air supply duct 180). In some embodiments,blower 110 is driven by a motor. Blower 110 may be operated at one or more speeds. This disclosure recognizes that operatingblower 110 at a higher speed provides an increased air flow rate relative to operatingblower 110 at a lower speed. In some embodiments,controller 110 controls the operation ofblower 110. As such,controller 110 may instructblower 110 to power on, power off, increase speed, and/or decrease speed. For example,controller 110 may instructblower 110 to power on (from an off mode) and operate at a speed corresponding to an air flow rate of 400 cubic feet per minute (“CFM”).Controller 110 may further instructblower 110 to increase speed (e.g., operate at a speed corresponding to an air flow rate of 600 CFM) and/or decrease speed (e.g., operate at a speed corresponding to an air flow rate of 200 CFM). - As described above, the air moved by
blower 110 is eventually directed throughair filter 120 viareturn air duct 150.Air filter 120 is configured to increase the quality of the air circulating inHVAC system 100 by entrapping pollutants. Pollutants may include particulates such as dust, pollen, allergens (e.g., dust mite and cockroach), mold, and dander. Pollutants may also include gases and odors such as gas from a stovetop, tobacco smoke, paint, adhesives, and/or cleaning products. Over time, asair filter 120 collects pollutants,air filter 120 becomes soiled and has no usable life left in it. This disclosure recognizes that an air filter having no usable life has reduced effectiveness at improving air quality relative to an air filter having usable life. Additionally, this disclosure recognizes that an air filter having no usable life increases the static pressure of the HVAC system, resulting in a higher cost toHVAC system 100 as compared to operating the HVAC system with an air filter having usable life. For example,blower 110 may require 0.925 KW of energy to move 1365 CFM when an air filter having usable life is installed withinHVAC system 100 but requires 1.07 KW of energy to move the same amount of air when an air filter having no usable life is installed withinHVAC system 100. To avoid these and other disadvantages, it is recommended that air filters are cleaned and/or replaced when they have no usable life left. -
HVAC system 100 may also include one ormore sensors 130.Sensors 130 may be configured to sense information aboutHVAC system 100, aboutenclosed space 105, and/or about components ofHVAC system 100. As an example,HVAC system 100 may include asensor 130 configured to sense data about a static pressure ofHVAC system 100. As another example, one or more sensors may be configured to sense data related to a temperature ofenclosed space 105. As yet another example, one or more sensors may be configured to sense data regarding a temperature and/or pressure leaving a condenser ofHVAC system 100. Although this disclosure describes specific types of sensors,HVAC system 100 may include any other type and any suitable number ofsensors 130. - As provided above,
HVAC system 100 includes at least onecontroller 140 that directs the operations ofHVAC system 100.Controller 140 may be communicably coupled to one or more components ofHVAC system 100. For example,controller 140 may be configured to receive data sensed bysensors 130. As another example,controller 140 may be configured to provide instructions to one or more components of refrigeration system 100 (e.g., blower 110).Controller 140 may be configured to provide instructions via any appropriate communications link (e.g., wired or wireless) or analog control signal. An example ofcontroller 140 is further described below with respect toFIG. 5 . In some embodiments,controller 140 includes or is a computer system. - As depicted in
FIG. 1 ,controller 140 is located within a wall-mounted thermostat inenclosed space 105. Operation ofHVAC system 100 may be controlled by an operator who programsHVAC system 100 using one ormore buttons 145 on the thermostat. For example,HVAC system 100 may be programmed to initiate a cooling cycle in response to determining user input viabuttons 145. As another example,HVAC system 100 may be programmed to initiate a filter calibration procedure in response to determining user input viabuttons 145. -
FIG. 2 illustrates amethod 200 of operation forHVAC system 100. In some embodiments, themethod 200 may be implemented by a controller of dehumidification system 200 (e.g.,controller 140 ofFIG. 1 ). As described above,method 200 may be stored on a computer readable medium, such as a memory of controller 140 (e.g.,memory 520 ofFIG. 5 ), as a series of operating instructions that direct the operation of a processor (e.g.,processor 530 ofFIG. 5 ).Method 200 may be associated with efficiency benefits such as reduced power consumption relative to conventional methods ofoperating HVAC system 100. In some embodiments, themethod 200 begins instep 205 and continues to step 210. - At
step 210,controller 140 initiates a filter calibration procedure. In some embodiments, the filter calibration procedure includes measuring the static pressure ofHVAC system 100 at a plurality of predetermined air flowrates. For example, filter calibration procedure may provide forHVAC system 100 to take static pressure measurements at 1333.33 CFM, 1666.67 CFM, and 2000 CFM from a baseline. As used herein, a “baseline” may refer to a flowrate of air from which other flowrates are determined (e.g., 1,333.33 CFM is 1,333.33 from abaseline 0 CFM).FIG. 3 illustrates examples of static pressure measurements taken at a plurality of air flowrates (e.g., see SP1, SP2, and SP3 ofFIG. 3 ). In some embodiments, a baseline may be set as soon as the filter calibration procedure is initiated. In some embodiments, the static pressure ofHVAC system 100 is measured viasensors 130. This disclosure recognizes that the filter calibration procedure may be initiated in any suitable way including, but not limited to, installation ofair filter 120 in an air duct ofHVAC system 100 and user input (e.g., depression ofbutton 245 on a thermostat). After completing the filter calibration procedure, themethod 200 may proceed to step 215. - At
step 215,controller 140 curve fits a first line based on the measurements taken during the filter calibration procedure. As an example, controller may generate an equation based on three or more sensed static pressure values measured at different air flowrates (e.g., 1,333.33 CFM, 1,666.67 CFM, and 2000.00 CFM). An example of such a curved-fit line is line 310 (indicated in dotted line) ofFIG. 3 . As depicted inFIG. 3 ,line 310 is curve fit based on static pressure (“SP”) points SP1, SP2, and SP3. Points alongfirst line 310 may represent values of a “clean” filter at a plurality of static pressure measurements and corresponding air flowrates. Although this disclosure may refer tofirst line 310 as a “clean filter” line, this disclosure recognizes thatair filter 120 may be partially or fully soiled when installed. In some embodiments, themethod 200 proceeds to astep 220 after curve fittingfirst line 310. - At
step 220,controller 140 generates a second line based on points of the first line. In some embodiments, the points along the second line are scaled from points along the first line using fan laws, a predetermined relationship or a system-derived relationship. An example of such scaled points are the three predicted points “PP” ofFIG. 3 (see PP1, PP2, and PP3 ofFIG. 3 ). The second line may be curve fit from the predicted points. An example of the generated second line is second line 320 (illustrated in dashed line) ofFIG. 2 . Points alongsecond line 320 may represent predicted values of a “dirty” filter at a plurality of static pressure measurements and corresponding air flowrates.Second line 320 may be represented by an equation. After generating the second line, themethod 200 may proceed to step 225. - At
step 225,controller 140 determines a first static pressure measurement ofHVAC system 100. The first static pressure measurement may be taken at a predetermined flowrate of air. For example, the first static pressure measurement may be determined at 1500 CFM from the baseline. In some embodiments, the first static pressure measurement is sensed bysensor 130. In other embodiments, the first static pressure measurement is calculated based on other values sensed by sensors 130 (e.g., 81.25% of max CFM of the HVAC unit). After determining the first static pressure measurement, themethod 200 may proceed to step 230. - At
step 230,controller 140 compares the first static pressure measurement to a predicted static pressure value. In some embodiments,controller 140 compares the first static pressure measurement to the predicted static pressure value at the predetermined flowrate of air. For example, if the first static pressure measurement was taken at 1500 CFM from the baseline,controller 140 compares the first static pressure measurement to a predicted static pressure value at 1500 CFM. Taking the measured pressures and predicted pressures ofFIG. 4 as an example,controller 140 may determine that at 1500 CFM, the first static pressure measurement ofHVAC system 100 is 0.18 inches of water (see MP1 ofFIG. 4 ) and the predicted pressure of second line (dirty filter line) 320 is about 0.22 inches of water. As such,controller 140 may compare 0.18 inches of water (MP1) to 0.22 inches of water (PPnot illustrated). - At
step 235,controller 140 determines whether the first static pressure measurement is greater than the predicted static pressure measurement. Taking the above example,controller 140 determines whether 0.18 inches of water (MP1) is greater than 0.22 inches of water (PPnot illustrated). Ifcontroller 140 determines that the first static pressure measurement is greater than the predicted static pressure measurement, themethod 200 may proceed to astep 240. Ifcontroller 140 instead determines that the first static pressure measurement is equal to or less than the predicted static pressure measurement, themethod 200 may proceed to step 230. - At
step 240,controller 140 determines thatair filter 120 has no more usable life. In some instances, themethod 200 proceeds to step 245 in response to making such determination. Atstep 245,controller 140 generates an alert. In some embodiments, the alert may be a visual alert such as a text-based alert for display on a thermostat and/or a user device (e.g., a cell phone). In some embodiments, the alert may be an audio alert (e.g., a beeping sound) from a thermostat and/or user device. Although this disclosure has described particular types of alerts, this disclosure recognizes any suitable alert. In some instances, an operator ofHVAC system 100 takes action in response to receiving the alert generated atstep 245. As an example, an operator ofHVAC system 100 may replace and/orclean air filter 120 in response to receiving the alert generated atstep 245. As another example, an operator of HVAC system may depressbutton 245 on wall-mounted thermostat in order to re-initiate the filter calibration procedure. In some embodiments, themethod 200 proceeds to endstep 250 after generating the alert. - In some other embodiments,
controller 120 performs one or more additional steps. For example, controller may perform one or more additional steps instead of proceeding to endstep 250. In such an example,controller 120 may continue to monitor the static pressure ofHVAC system 100 after determining atstep 235 that the first static pressure measurement is equal to or less than the predicted static pressure measurement. In some embodiments,controller 140 may perform further comparison and determination steps. For example,controller 150 may determine a static pressure ofHVAC system 140 at 1800 CFM and compare the static pressure to a predicted value of static pressure at 1800 CFM. Taking the values ofFIG. 4 as an example, controller may determine that the static pressure ofHVAC system 100 at 1800 CFM is about 0.23 inches of water (see MP2 ofFIG. 4 ) and compare it to a predicted value of static pressure at 1800 CFM (about 0.31 inches of water).Controller 140 may further determine that the measured value of static pressure (about 0.23 inches of water) is less than the predicted value of static pressure at 1800 CFM (about 0.31 inches of water).Controller 140 may continue to perform such determination and comparison steps as necessary. For example,controller 140 may continue to perform these determination and comparison steps untilcontroller 140 determines that a measured static pressure at CFMX is greater than a predicted static pressure at CFMX. An example of such determination is depicted inFIG. 4 when the measured static pressure at 2200 CFM (see MP6 having a static pressure of about 0.52 inches of water) exceeds the corresponding predicted static pressure (about 0.485 inches of water) at 2200 CFM. - Although this disclosure describes and depicts detecting a static pressure above a predicted pressure, this disclosure also recognizes detecting whether the static pressure of the HVAC system is stagnant or declining. In some cases, stagnant or declining measurements of static pressure of
HVAC system 100 may indicate that anair filter 120 having no usable life is installed withinHVAC system 100. This may occur when, for example, an operator attempts to foolHVAC system 100 by initiating the calibration procedure without replacing/cleaningair filter 120. In such circumstances,HVAC system 100 may receive substantially similar static pressure measurements (e.g., +/−10% of a first measured static pressure) at a plurality of air flowrates (e.g., 1,333.33 CFM, 1,666.67 CFM, 2000.00 CFM) during the filter calibration procedure, and then continue to receive substantially similar static pressure measurements after completing the filter calibration procedure. TheHVAC system 100 may be further programmed to generate an alert in response to determining that the static pressure of the HVAC system is not increasing at an expected rate (e.g., determining that the static pressure of the HVAC system is +/−10% of 0.45 inches of water when measured at 1200 CFM, 1600 CFM, 2000 CFM, and 2400 CFM). -
FIGS. 3 and 4 are graphs illustrating one or more steps ofmethod 200. For example,FIG. 3 illustrates static pressure measurements taken during the filter calibration procedure described above in reference to step 210, curve-fitting a first line from the static pressure measurements taken during the filter calibration procedure as described above in reference to step 220, and generating a second line based on the first line as described above in reference to step 230. As depicted inFIG. 3 , three static pressure measurements are taken at three different flowrates of air: SP1, SP2, and SP3. As illustrated, SP1 is about 0.15 inches of water at 1,333.33 CFM, SP2 is about 0.21 inches of water at 1,666.67 CFM, and SP3 is about 0.29 inches of water at 2000.00 CFM.First line 310 ofFIG. 3 is determined based on the static pressure measurements taken during the filter calibration procedure.First line 310 may be represented as an equation (e.g., y=5.06437E-08x2+4.27026E-0.5x). As discussed above,line 310 may represent values of a “clean” filter at a plurality of static pressure measurements and corresponding air flowrates.FIG. 3 also illustrates a plurality of predicted static pressures: PP1, PP2, and PP3. As illustrated, PP1 is about 0.19 inches of water at 1,333.33 CFM, PP2 is about 0.28 inches of water at 1,666.67 CFM, and PP3 is about 0.39 inches of water at 2000.00 CFM. In some embodiments, the values of PP1, PP2, and PP3 are scaled from the values of SP1, SP2, and SP3, respectively, using fan laws. In some embodiments, the values of PP1, PP2, and PP3 are used to generatesecond line 320.Second line 320 may be represented as an equation (e.g., y=7.56437E-08x2+4.27026E-05x). -
FIG. 4 illustratesfirst line 310 andsecond line 320 ofFIG. 3 in addition to illustrating a plurality of static pressure measurements taken at predetermined flowrates of air (see MP1, MP2, MP3, MP4, MP5, and MP6). As illustrated, MP1 is about 0.18 inches of water at 1500.00 CFM, MP2 is about 0.23 inches of water at 1800.00 CFM, MP3 is about 0.275 inches of water at 1900.00 CFM, MP4 is about 0.35 inches of water at 2000 CFM, MP5 is about 0.42 inches of water at 2100 CFM, and MP6 is about 0.52 inches of water at 2200 CFM. As described above in reference tosteps 225,controller 140 determines the static pressure ofHVAC system 100 asblower 110 moves predetermined flowrates of air. These values may then be compared against either values offirst line 310 and/or values ofsecond line 320 to determine whetherair filter 120 has remaining usable life. - In addition to determining whether
air filter 120 no remaining usable life, this disclosure also recognizes thatcontroller 140 can predict howdirty air filter 120 is. This prediction is referred to herein as a percent dirty (or soilage percentage) ofair filter 120. In some embodiments,controller 140 determines percent dirty using the following formula: -
- wherein PPX indicates a predicted static pressure of
HVAC system 100 along second line 310 (dirty line 310) at a given CFM, MPX indicates a measured static pressure ofHVAC system 100 at the given CFM, and SPX indicates a predicted static pressure ofHVAC system 100 along first line 100 (clean line 100) at a given CFM. In some embodiments,controller 140 determines percent dirty as above but substitutes MPavg for MPX, wherein MPavg is equal to an average of samples in a data set. Although this disclosure describes and depicts using each value either predicted by an equation and/or measured byHVAC system 100, this disclosure recognizes that conventional scientific principles should be applied in evaluating these values. For example,controller 140 may be programmed to discard data which it determines are outliers. -
Controller 140 may be further programmed to generate one or more additional alerts based on a soilage percentage ofair filter 120. For example,controller 140 may be configured to generate an alert in response to determining thatair filter 120 has a dirtiness percentage of 10% or less. Although this disclosure describes a specific alert threshold, this disclosure recognizes that this alert threshold may be set at any suitable percentage, and in some embodiments, may be set by an operator ofHVAC system 100. -
FIG. 5 illustrates anexample controller 140 ofHVAC system 100, according to certain embodiments of the present disclosure.Controller 140 may comprise one ormore interfaces 510,memory 520, and one ormore processors 530.Interface 510 receives input (e.g., sensor data, user input), sends output (e.g., instructions), processes the input and/or output, and/or performs other suitable operation.Interface 510 may comprise hardware and/or software. -
Processor 530 may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or all of the described functions ofcontroller 140. In some embodiments,processor 530 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), and/or other logic. - Memory (or memory unit) 520 stores information.
Memory 520 may comprise one or more non-transitory, tangible, computer-readable, and/or computer-executable storage media. Examples ofmemory 520 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), database and/or network storage (for example, a server), and/or other computer-readable medium. - Modifications, additions, or omissions may be made to the systems, apparatuses, and methods described herein without departing from the scope of the disclosure. The components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses may be performed by more, fewer, or other components. For example, the HVAC system may include any suitable number of compressors, condensers, condenser fans, evaporators, valves, sensors, controllers, and so on, as performance demands dictate. One skilled in the art will also understand that the HVAC system contemplated by this disclosure can include other components that are not illustrated but are typically included with HVAC systems. Additionally, operations of the systems and apparatuses may be performed using any suitable logic comprising software, hardware, and/or other logic. As used in this document, “each” refers to each member of a set or each member of a subset of a set.
- Modifications, additions, or omissions may be made to the methods described herein without departing from the scope of the disclosure. The methods may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order.
- Although this disclosure has been described in terms of certain embodiments, alterations and permutations of the embodiments will be apparent to those skilled in the art. Accordingly, the above description of the embodiments does not constrain this disclosure. Other changes, substitutions, and alterations are possible without departing from the spirit and scope of this disclosure.
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US20210060474A1 (en) * | 2019-08-29 | 2021-03-04 | Carl Freudenberg Kg | Method for predicting the service life of a filter |
CN114783155A (en) * | 2022-04-27 | 2022-07-22 | 董云龙 | Pressure monitoring and alarming device for air conditioner refrigerant water system |
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EP1161303A1 (en) * | 2000-01-14 | 2001-12-12 | The Holmes Group, Inc. | Filter-fan product including a circuit for monitoring the filter thereof |
US6778864B1 (en) * | 2000-09-06 | 2004-08-17 | Visteon Global Technologies, Inc. | System and method for analyzing a component |
US6882280B2 (en) * | 2001-07-16 | 2005-04-19 | Maytag Corporation | Electronic message center for a refrigerator |
US7261762B2 (en) * | 2004-05-06 | 2007-08-28 | Carrier Corporation | Technique for detecting and predicting air filter condition |
US9183723B2 (en) * | 2012-01-31 | 2015-11-10 | Cleanalert, Llc | Filter clog detection and notification system |
US9120366B2 (en) * | 2012-04-27 | 2015-09-01 | Ford Global Technologies, Llc | Monitoring air filter status in automotive HVAC system |
US10088185B2 (en) * | 2015-03-30 | 2018-10-02 | Gridpoint, Inc. | Thermostat with integrated submetering and control |
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US20210060474A1 (en) * | 2019-08-29 | 2021-03-04 | Carl Freudenberg Kg | Method for predicting the service life of a filter |
CN114783155A (en) * | 2022-04-27 | 2022-07-22 | 董云龙 | Pressure monitoring and alarming device for air conditioner refrigerant water system |
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