UNITED STATES PATENT AND TRADEMARK OFFICE
`_______________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`_____________
`
`GOOGLE LLC
`
`Petitioner
`
`v.
`
`ECOFACTOR, INC.
`
`(record) Patent Owner
`
`IPR2022-00538
`
`Patent No. 9,194,597
`
`REPLY DECLARATION OF RAJENDRA SHAH
`
`1
`
`GOOGLE 1021
`
`
`_______________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`_____________
`
`GOOGLE LLC
`
`Petitioner
`
`v.
`
`ECOFACTOR, INC.
`
`(record) Patent Owner
`
`IPR2022-00538
`
`Patent No. 9,194,597
`
`REPLY DECLARATION OF RAJENDRA SHAH
`
`1
`
`GOOGLE 1021
`
`
`
`TABLE OF CONTENTS
`I. ENGAGEMENT AND INTRODUCTION ........................................................ 3
`II. ADDITIONAL OPINIONS REGARDING THE UNPATENTABILITY OF
`THE ’597 PATENT ................................................................................................... 3
`A. Ehlers’ 330’s “Thermal Gain Rates” Are Rates of Change In Inside
`Temperature Over Time .......................................................................................... 3
`B. Ehlers ’330’s Figures 3E and 3G Are Consistent With This Understanding . 11
`C. Ehlers ’330’s Thermal Gain Rates Predict a Speed that Inside Temperature
`Will Change in Response to Changes in Outside Temperature ........................... 17
`III. OATH ................................................................................................................ 27
`
`2
`
`
`
`I.
`
`ENGAGEMENT AND INTRODUCTION
`I am that same Rajendra Shah who previously submitted a declaration
`
`
`in the present Inter Partes Review in which I set forth certain opinions regarding the
`
`unpatentability of U.S. Pat. No. 9,194,597 (“the ’597 patent”) (“the First Shah
`
`Declaration”). My qualifications are set forth in the First Shah Declaration and my
`
`curriculum vitae is attached as Exhibit 1003 thereto.
`
`
`
`I understand that the Patent Trial and Appeal Board (“Board”) has
`
`issued an Order granting Google, LLC’s (“Google”) Petition for Inter Partes Review.
`
`I further understand that Dr. John A. Palmer has submitted a declaration on behalf
`
`of Patent Owner EcoFactor Inc. in this proceeding (“the Palmer Declaration”) in
`
`which he has offered certain opinions in response to the opinions set forth in the First
`
`Shah Declaration. I have reviewed the Palmer Declaration and the Exhibits cited
`
`therein. I have been asked by Google to provide additional opinions regarding the
`
`unpatentability of the ’597 patent in response to the opinions offered by Dr. Palmer.
`
`These additional opinions are set forth herein.
`
`II. ADDITIONAL OPINIONS REGARDING THE UNPATENTABILITY
`OF THE ’597 PATENT
`A. Ehlers’ 330’s “Thermal Gain Rates” Are Rates of Change In Inside
`Temperature Over Time
`As I explained in detail in the First Shah Declaration, Ehlers ’330
`
`
`teaches calculating the rate at which temperature inside a structure changes over time
`
`
`
`3
`
`
`
`at any given outside temperature (i.e., the “thermal gain rate”). Ehlers ’330
`
`illustrates this in Figure 3D, reproduced below.
`
`(Ex. 1004, Fig. 3D). As I further explained in detail in the First Shah Declaration,
`
`a POSITA would understand that in Figure 3D of Ehlers ’330, the HVAC system is
`
`“OFF” and the inside temperature is permitted to change or ‘drift’ in response to
`
`the outside temperature.1
`
`
`
`
`1 It appears that Dr. Palmer agrees with me and recognizes that that “information
`presented in Fig. 3D of Ehlers ’330 only relates to changes in temperature when
`the HVAC system is OFF” and that “the ‘thermal gain rates’ qualitatively
`illustrated in Fig. 3D are only for a building with an HVAC system turned OFF.”
`(See Ex. 2008, ¶54)(See also id. ¶56)(“Ehlers ’330 determines the thermal gain of
`
`
`
`
`4
`
`
`
`
`
`Ehlers ’330 specifically describes Figure 3D as depicting what Ehlers
`
`’330 refers to as the “thermal gain rate” of the home. Ehlers ’330 states: “the
`
`system 3.08 tracks the thermal gain rate of the home 2.18 for each set point
`
`selected over time by the customer.” (Ex. 1004, ¶0253). Ehlers ’330 goes on to
`
`state that “lines 3.12A, 3.12B, and 3.12C plot the thermal rate of gain in the site
`
`1.04 for different outside temperatures.” (Ex. 1004, ¶0253)(see also id.)(“The
`
`three trends shown as lines 3.14A, 3.14B, and 3.14C illustrate the thermal rate of
`
`gain in the home 2.18.”)(emphases added). Ehlers ’330 further states that “these
`
`graphs are drawn to illustrate the rate of thermal gain.” (Ex. 1004, ¶0253).
`
`
`
`Ehlers ’330 also explains:
`
` “[w]hile these graphs are drawn to illustrate the rate of thermal gain,
`
`they do not depict the rapid initial gain when the differential is large
`
`and the slower rate of thermal gain, which occurs as the indoor
`
`temperature reaches the outside temperature. This rate [of] thermal gain
`
`change is illustrated in FIG. 3D as plot line 3.16 which shows the
`
`
`the building under only certain conditions. Ex. 1004, ¶253, Fig. 3D. This involves,
`as Mr. Shah admits, turning the HVAC off and then measuring how much the
`inside temperature increases over time when at a certain outside temperature.”)(id.
`¶59)(“At best, the data in Fig 3D discloses the changes in inside temperature from
`a specific starting temperature and for a single, specific outside temperature when
`the HVAC system is OFF.”)(id., ¶38)(recognizing that “the slope of the line” in
`Figure 3D is the “rate of change of temperature”).
`5
`
`
`
`
`
`thermal gain for a set point of 74 degree F. and an outside temperature
`
`of 90 degrees F.”
`
`(Ex. 1004, ¶0253).
`
`
`
`I observe that Ehlers ’330 specifically states that the rate of thermal
`
`gain decreases “as the indoor temperature reaches the outside temperature.” (Ex.
`
`1004, ¶0253). A POSITA would understand that under the circumstances depicted
`
`in Figure 3D, the HVAC system is “OFF” and not cycling such that the indoor
`
`temperature is permitted to change to eventually “reach[] the outside temperature.”
`
`I observe that in no instance depicted in Figure 3D does the inside temperature
`
`exceed the outside temperature applicable to each line depicted, which is consistent
`
`with Ehlers ’330’s teachings. Nor does the inside temperature ever rise above about
`
`80 degrees F.
`
`
`
`The x axis of Figure 3D represents time in minutes and the y axis of
`
`Figure 3D represents temperature in degrees Fahrenheit. Each of the lines depicted
`
`in Figure 3D thus represents “rates” at which the temperature (y axis) in the structure
`
`changes over time (x axis). The x-axis of Figure 3D specifically suggests that
`
`temperature data be acquired every 4 minutes. In my opinion, Ehlers ’330 clearly
`
`and unequivocally uses the term “thermal gain rate” (or “rate of thermal gain” or
`
`variations thereof) to refer to the rate of change of inside temperature over time in
`
`
`
`6
`
`
`
`the structure in the context of Figure 3D. (See also, e.g., Ex. 1004, ¶0255)(“the rate
`
`of thermal gain per hour would be set at 3 degrees F. per hour”).
`
`
`
`I observe that Dr. Palmer appears to agree that the slopes of the lines
`
`depicted in Figure 3D represent rates of change of temperature. (Ex. 2008,
`
`¶38)(“The lines appear to reflect temperatures rather than rates of energy increase.”)
`
`(id., ¶38)(recognizing that “the slope of the line” in Figure 3D is the “rate of change
`
`of temperature”). As explained above, Ehlers ’330 specifically states that these lines
`
`“plot the thermal rate of gain” and “illustrate the rate of thermal gain.” (See also Ex.
`
`1004, ¶0253).
`
`
`
`Figure 3D of Ehlers ’330 illustrates the concept of thermal gain rate as
`
`a function of both inside and outside temperatures. Figure 3D visually demonstrates
`
`that for the same inside temperature, the higher the outside temperature, the greater
`
`is the rate of change of inside temperature in response to that outside temperature.
`
`Furthermore, Figure 3D also illustrates that the greater the differential between the
`
`inside and the outside temperature, the greater the thermal gain rate (the rate of
`
`change of inside temperature) will be in response. (See, e.g., Ex. 1004, ¶0253)(“This
`
`illustration is used to show the impact the set point versus outside temperature
`
`differential has over the thermal gain rate in the home 2.18.”).
`
`
`
`In my opinion, a POSITA would recognize that it would be desirable to
`
`obtain data such as that depicted in Figure 3D for a number of different inside and
`
`
`
`7
`
`
`
`outside temperatures in order to develop accurate predictions for how inside
`
`temperature changes in response to changes in outside temperature for a particular
`
`structure. In my opinion, it would have been straightforward both to acquire and to
`
`interpolate thermal gain rate data for other indoor and outdoor temperatures. Some
`
`of this data collection could be done, for example, when a system is first installed
`
`and before the building at issue is occupied. Ehlers ’330 also states that collecting
`
`and tracking of data would be done in a continuous manner. (See, e.g., Ex. 1004,
`
`¶0256). A POSITA would understand that it would be desirable to do so such that
`
`the data best represents the current characteristics of the structure.
`
` This data can be used, as taught by Ehlers ’330 to compute, for example
`
`an “average normalized thermal gain or loss for the site 1.04.” (Ex. 1004, ¶0295).
`
`It can also be used to compute, for example, the information depicted in Figure 3E
`
`(discussed in further detail below). (Ex. 1004, Fig. 3E).
`
`
`
`8
`
`
`
`
`
`Specifically, the dashed line in Figure 3E illustrates how the thermal gain rate for a
`
`structure changes over time in response to changes in outside temperature
`
`throughout the day. Based on the teachings in Ehlers ’330, in my opinion, a POSITA
`
`would understand how to collect and/or generate the kind of data depicted in Figure
`
`3D and use that data to generate thermal gain rate plots such as that depicted in
`
`Figure 3E.
`
` Dr. Palmer states that “the phrase ‘thermal gain rate’ is well understood
`
`by a POSITA to be the rate at which energy is absorbed.” (Ex. 2008, ¶37). I note
`
`that Dr. Palmer cites nothing in support of that statement. Regardless of how the
`
`term may or may not be used in other contexts, it is clear to me that within the context
`
`
`
`9
`
`
`
`of Ehlers ’330’s disclosure, Ehlers ’330 uses the term to refer to the rate of change
`
`of inside temperature over time.
`
`
`
`I also note that Ehlers ’330 measures and quantifies the “thermal gain
`
`rate” at various points. (See, e.g., Ex. 1004, ¶¶0253-256, Figs. 3D-3G). While doing
`
`so, Ehlers ’330 does not describe “thermal gain rates” as an amount or rate at which
`
`“energy is absorbed” by a structure, nor does Dr. Palmer identify any such teachings
`
`separate and apart from instruction to measure the temperature in a structure and
`
`determine the rate at which that inside temperature changes over time, and I am
`
`aware of none. Instead, Ehlers ’330 clearly uses the term “thermal gain rate” to refer
`
`to the rate of change of inside temperature in a structure over time.
`
`
`
`In describing Figure 3D, Dr. Palmer states that “[i]f read literally,
`
`Ehlers ’330’s description would indicate that the thermal gain rate would be a
`
`continuously increasing value between 72 and 80 (units unspecified).” (Ex. 2008,
`
`¶38). I disagree. A POSITA reading Figure 3D would clearly understand that the
`
`“thermal gain rate[s]” in Figure 3D are the slopes of the various lines depicted. In
`
`the straight lines depicted in Figure 3D, the thermal gain rate is, of course, a constant.
`
`Curved line 3.16, as Ehlers ’330 explains, and as I explain above, illustrates the
`
`“rapid initial gain when the differential is large and the slower rate of thermal gain,
`
`which occurs as the indoor temperature reaches the outside temperature.” (Ex. 1004,
`
`¶0253).
`
`
`
`10
`
`
`
` Ehlers ’330 teaches and a POSITA would understand that the rate of
`
`change of inside temperature, due to outside conditions, does not remain constant
`
`throughout a day. (Ex. 1004, ¶0253, Fig. 3D). As the inside temperature increases,
`
`the difference between the outside and inside temperature decreases, which causes
`
`the rate of change of inside temperature to decrease as well, as specifically illustrated
`
`in Fig 3D, Line 3.16. Also, as would be apparent to a POSITA, the outside
`
`temperature does not remain at a high level as the day progresses into the evening
`
`and night. As the outside temperature falls, so does the rate of change of inside
`
`temperature.
`
`B. Ehlers ’330’s Figures 3E and 3G Are Consistent With This
`Understanding
`In an HVAC “cycle,” the percent run time (HVAC Run %) is the
`
`
`percent of time in the cycle the HVAC system is ON and actively working to change
`
`the temperature in a structure. As is apparent to a POSITA, during normal
`
`unrestricted operation, as the HVAC system cycles “ON” and “OFF,” its % run time
`
`increases or decreases to balance the thermal gain rate of the structure—e.g., to keep
`
`the net rate of change in indoor temperature over time at or close to zero. For
`
`example, in the “cooling” context, when the HVAC system is ON and cooling, the
`
`system can reduce the temperature inside the structure despite the warming effect
`
`due to the outside conditions. A POSITA can consider this to be a “negative”
`
`
`
`11
`
`
`
`thermal gain rate that not only balances but overcomes the “positive” thermal gain
`
`rate of the structure which occurs when the system is OFF.
`
` The net effect of the operation of the system is to keep the inside
`
`temperature essentially unchanged at or near the setpoint. A POSITA knows that
`
`the purpose of an HVAC system under thermostatic control is to balance the rate of
`
`change of inside temperature due to outside conditions and to maintain the inside
`
`temperature at or near the user’s desired setpoint. In other words, the HVAC system
`
`cycles ON and OFF to effectively balance out the overall full cycle average rate of
`
`change of inside temperature at or near zero.
`
` Figure 3E of Ehlers ’330 illustrates how the daily outdoor temperature
`
`variation results in a variation in the thermal gain rate variation and a
`
`corresponding variation in HVAC run time %. A POSITA would understand that
`
`this example is in summer when the HVAC system is in the cooling mode. In
`
`Figure 3E, the horizontal axis is time in hours covering a 24-hour day. The left
`
`vertical axis is the HVAC system run time in % (i.e., the percentage of time in a
`
`cycle in which the HVAC system is ON and, in this context, cooling). The right
`
`vertical axis is the thermal gain rate in degrees Fahrenheit per hour. Ehlers ’330
`
`explains that this thermal gain rate is expected to change over the day, as graphed
`
`in the dashed line, in response to changes in outside temperatures during the day.
`
`(Ex. 1004, ¶0254). Figure 3E (and Figure 3G, discussed below) specifically depict
`
`
`
`12
`
`
`
`how the thermal gain rate changes throughout the day in response to changes in
`
`outside temperature throughout the day. (See, e.g., Ex. 1004, ¶0256)(“As the
`
`outside temperature rises, the thermal gain on the home 2.18 is monitored . . . on a
`
`continuous basis.”). Ehlers ’330’s thermal gain rates are calculated and monitored
`
`with changes in outside temperature.
`
` As shown in Figure 3E, the HVAC run time % correlates with the
`
`thermal gain rate. As Ehlers ’330 explains, the setpoint is fixed at the same level
`
`through the entire day and the HVAC system cycles “ON” and “OFF” throughout
`
`the day as necessary to maintain the inside temperature at or near the setpoint. As
`
`the time progresses from late night to morning and then afternoon, the outside
`
`temperature increases and so does the inside temperature during the periods of time
`
`in which the HVAC system is OFF. During these periods of time, the thermal gain
`
`rate of the structure is positive and increases as the temperature differential between
`
`inside and outside temperature increases. This would substantially increase the
`
`actual inside temperature itself over time, if it were not for the HVAC system
`
`delivering sufficient cooling during the periods of time in which it is ON, effectively
`
`balancing and overcoming the thermal gain rate as I describe above, to maintain the
`
`average inside temperature at or near the setpoint.
`
`
`
`In each typical HVAC cycle, during normal operation, when the system
`
`is OFF, the inside temperature increases at the thermal gain rate associated with the
`
`
`
`13
`
`
`
`applicable inside and outside temperatures (as shown in Fig. 3D). As the inside
`
`temperature increases sufficiently above the setpoint, the HVAC system turns ON
`
`and runs in cooling mode until the inside temperature cools down to the setpoint. At
`
`that point, the HVAC system turns OFF again, and the cycle repeats. This is shown
`
`in the exemplary diagram below, which I have created based on the information
`
`presented in Figure 3E. Specifically, I have chosen approximately 11 am where
`
`Figure 3E illustrates a thermal gain rate of approximately 2.5 degrees F/hour and a
`
`corresponding HVAC run % of approximately 60%.
`
`Exemplary Thermosta�c Cycle Control of HVAC System, Ehlers ‘330
`Cooling Mode, based on Fig. 3E @ ~11 am
`
`Cooling Cycle 120 min.
`
`OFF 48 min.
`
`Upper Temp. Control Limit
`
`RUN 72 min.
`60% Run Time
`
`76F
`
`74F
`
`Dead-band
`
`Inside Temperature
`
`
`
`Setpoint
`
`72F
`
`Lower Temp. Control Limit
`30
`
`0
`
`60
`
`90
`Time in Minutes
`
`120
`
`150
`
`180
`
`Example Diagram A
`
`
`
`
`
`14
`
`
`
` Thus, a POSITA would understand that the “thermal gain rates”
`
`specifically graphed in Figure 3E (as well as Figure 3G, discussed below) represent
`
`rates of change of inside temperature during the portion(s) of the cycle when the
`
`HVAC system is OFF. The HVAC run time % graphed is the percentage of the
`
`cycle that the system needs to run in order to balance or counteract that thermal gain
`
`rate. I further note that the fact that the “thermal gain rate[s]” illustrated in both
`
`Figures 3E and 3G are similar supports my interpretation. In Figures 3E and 3G, the
`
`HVAC system is operating at different amounts and thus, the effect of the HVAC
`
`system on the inside temperature should be different. However, in Figures 3E and
`
`3G, the rate of change of inside temperature when the system is “OFF” and not
`
`cooling under similar conditions would be expected to be similar.
`
`
`
`I note that Dr. Palmer suggests that Ehlers ’330 does not measure the
`
`“thermal gain rates” for a building when the HVAC system is “ON” and functioning.
`
`I observe that the challenged claims do not specifically require the system to
`
`determine the rate of change of inside temperature for a building when the HVAC
`
`system is ON and functioning.
`
` Nonetheless, in my opinion, Ehlers ’330 teaches this as well. For
`
`example, Ehlers ’330 states that “[a]s the outside temperature rises, the thermal gain
`
`on the home 2.18 is monitored along with the HVAC cycle rate on a continuous
`
`basis. The rise in the outside temperature causes the HVAC cycle time to increase
`
`
`
`15
`
`
`
`as illustrated in FIG. 3E.” (Ex. 1004, ¶0256)(Emphasis added). In my opinion, a
`
`POSITA would recognize that the “thermal gain” as well as the “HVAC cycle rate”
`
`are both being measured “on a continuous basis” and thus, the system is also
`
`measuring the thermal gain rate during periods when the status of the HVAC system
`
`is “ON”.
`
` Ehlers ’330 also states that it computes and stores a “[c]omputed
`
`thermal recovery time for heating and cooling adjusted to compensate for the
`
`external temperature.” (Ex. 1004, ¶0295)(Emphasis added). Ehlers ’330 explains
`
`that “this computed factor is used to more accurately compute the recovery time
`
`for thermal gain or loss when combined with the average normalized thermal gain
`
`or loss for the site 1.04.” (Id.)(Emphasis added). Ehlers ’330 further explains that
`
`it stores “[t]he average thermal recovery time per degree when heating and
`
`cooling systems are operational for a rolling 30, 60, and 90 day period by hour of
`
`the day.” (Ex. 1004, ¶0285)(Emphasis added). In my opinion, a POSITA would
`
`also understand from these disclosures that Ehlers ’330 computes rates of change of
`
`temperature in the structure when the system is “ON.” For example, “[t]he average
`
`thermal recovery time per degree when heating and cooling systems are operational”
`
`is a rate of time per degree of temperature (Δt/ΔT). This value can also be expressed
`
`as (ΔT/ Δt), which is the rate of temperature change over time. In my opinion, a
`
`POSITA would further understand that this rate is calculated when the HVAC
`
`
`
`16
`
`
`
`system is “ON” because the HVAC system will be on and running during at least
`
`some portion of the time during which the HVAC system is operational. A POSITA
`
`would also understand that these rates change are in response to changes in outside
`
`temperature by virtue of being adjusted to take into account the outside temperature.
`
`(Ex. 1004, ¶0295).
`
` Furthermore, as illustrated in my exemplary diagram A (above), it is
`
`also a straightforward matter to calculate the corresponding “balancing” rate of
`
`thermal gain when the system is “ON” by simply determining the rate of change that
`
`would be needed to return the inside temperature to the setpoint during the “ON”
`
`portion of a cycle. I have specifically done this for illustrative purposes with a 2-
`
`degree “normal deadband” and a cycle of 120 minutes. (See, e.g., Ex. 1004, ¶0255).
`
`C. Ehlers ’330’s Thermal Gain Rates Predict a Speed that Inside
`Temperature Will Change
`in Response to Changes
`in Outside
`Temperature
` The reason that Ehlers ’330 “tracks and learns about the thermal gain
`
`characteristics of the home” (Ex. 1004, ¶0253) is to be able to use that data to make
`
`predictions about the future behavior of the inside temperature in the home. This
`
`information is then used in controlling the system to “manage costs and comfort.”
`
`(Ex. 1004, ¶¶0252-0253).
`
` Ehlers ’330 uses the thermal gain rates as predicted rates of change in
`
`order to predict changes in inside temperature various ways.
`
`
`
`17
`
`
`
` First, one way in which Ehlers ’330 does so is when they are used to
`
`determine a new offset temperature in connection with a demand reduction request
`
`and/or reducing demand in response to a change in energy pricing. As I explain,
`
`Ehlers ’330 uses the “computed thermal gain rate” to “compute[] the required
`
`effective set point offset needed to keep the HVAC cycle run time at [a] specified
`
`trigger level.” (Ex. 1004, ¶0256). To do so, Ehlers ’330 predicts that the thermal
`
`gain rate it computed in the past represents a speed a temperature inside the first
`
`location will change in response to changes in outside temperature at the current time
`
`or at a time in the future. A POSITA would understand that the thermal gain rate is
`
`used as a predicted rate of change in the context of the example described in
`
`paragraph 256 of Ehlers ’330.
`
`
`
`In paragraph 256 of Ehlers ’330, Ehlers ’330 describes a specific
`
`example of how it “uses the thermal gain rate of the home 2.18” “to manage the
`
`demand and consumption rate at either a flat level or at some reduced level by
`
`varying the indoor air temperature within the allowable range.” (Ex. 1004, ¶0256).
`
`Ehlers ’330 describes an example in which “the set point of the thermostat is 72
`
`degrees F and the allowed variation selected by the customer is 4 degrees F. making
`
`the acceptable range for indoor temperature from 72 degrees F. to 76 degrees F.”
`
`(Ex. 1004, ¶0256). What Ehlers ’330 is describing in this example is an instance in
`
`which the customer has enabled a setting which permits the system to vary the
`
`
`
`18
`
`
`
`setpoint by up to 4 degrees (i.e., 76 degrees F) in order to save energy. (See, e.g.,
`
`Ex. 1004, ¶0255) (“In the maximum savings setting, the set point offset would be 4
`
`degrees F. which would permit the system in this example to vary the temperature
`
`in the home [from] the normal set point of 72 F by the 4 degree offset making the
`
`acceptable temperature range 72 F to 76 F within which the system 3.08 would
`
`manage the environment.”). In the example described in paragraph 256, while the
`
`customer has permitted the system to vary the setpoint by up to 4 degrees, the system
`
`need not do so if a smaller setpoint offset would accomplish the system’s energy
`
`savings goals, as explained below. (See also, e.g., Ex, 1004, ¶0141)(“ The setpoints
`
`are offset and the temperature is monitored. . . . By adjusting the setpoint of the
`
`thermostat 1.30D, the actual consumption of the HVAC system should reduce as a
`
`result of a higher setpoint for heating or cooling being established.”). This can be
`
`seen from Ehlers ’330’s statement that the system “computes the required effective
`
`set point offset needed to keep the HVAC cycle run time at the specified trigger level
`
`of 33%. (Ex. 1004, ¶0256)(emphasis added).
`
`
`
`In this example, to reduce energy consumption, the customer has
`
`specified that the HVAC system is only permitted to be “ON” for a maximum of
`
`33% of an HVAC cycle (i.e., a 33% HVAC run time). (Ex. 1004, ¶0256)(“For this
`
`example it is assumed that the customer has set the base line trigger to be set when
`
`the HVAC unit’s run time reaches 33%.”). However, at some point, in this example,
`
`
`
`19
`
`
`
`due to the increase in outside temperature in the middle of the day, the HVAC system
`
`will need to operate more than 33% of the time to cool the home to the setpoint of
`
`72 degrees. In order to maintain the maximum HVAC run time % at 33%, the system
`
`uses the thermal gain rate to compute a new setpoint somewhere between 72 and 76
`
`degrees, which will require no more than 33% cycling time to maintain. Ehlers ’330
`
`explains this process as follows:
`
`“In the early morning when it is cool, the system 3.08 in this example
`
`will be operating at a cycle rate of 10%. As the outside temperature
`
`rises, the thermal gain on the home 2.18 is monitored along with the
`
`HVAC cycle rate on a continuous basis. The rise in the outside
`
`temperature causes the HVAC cycle time to increase as illustrated in
`
`FIG. 3E. As the system 3.08 reaches the trigger level of 33% cycle run
`
`time, the base line is established and the system 3.08 using its
`
`computed thermal gain rate and the corresponding HVAC cycle
`
`run time projections, computes the required effective set point
`
`offset needed to keep the HVAC cycle run time at the specified
`
`trigger level of 33%. By adjusting the effective set point upward,
`
`the system 3.08 is able to maintain the HVAC run time at the
`
`predetermined trigger level up to the point that the thermal gain rise rate
`
`exhausts the allowed temperature variant allowed for the site 1.04.”
`
`
`
`20
`
`
`
`(Ex. 1004, ¶0256)(emphasis added)(See also, e.g., Ex, 1004, ¶0141)(“The setpoints
`
`are offset and the temperature is monitored. . . . By adjusting the setpoint of the
`
`thermostat 1.30D, the actual consumption of the HVAC system should reduce as a
`
`result of a higher setpoint for heating or cooling being established.”)(emphasis
`
`added)(Fig. 3F)(illustrating an increase in the “indoor setpoint”).
`
` Ehlers ’330 explains that Figure 3G, reproduced below, “illustrates this
`
`scenario, assuming that the thermal gain of the site 1.04 does not exhaust the allowed
`
`temperature variant for the site 1.04.” (Ex. 1004, ¶0256).
`
` At some point, despite setting the thermostat to 76 degrees Fahrenheit
`
`(the maximum setpoint allowed in this example), the inside temperature in the home
`21
`
`
`
`
`
`
`
`may be increasing too rapidly for the system to maintain a 33% HVAC run time. As
`
`can be seen in the quotation reproduced above, Ehlers ’330 describes this situation
`
`as one in which “the thermal gain rise rate exhausts the allowed temperature variant
`
`allowed for the site 1.04.” (Ex. 1004, ¶0256). As Ehlers ’330 explains, under such
`
`circumstances, the system can either allow the cycle rate to increase above 33% or
`
`allow the home to “exceed the allowed temperature.” (Ex. 1004, ¶0256).
`
` Ehlers ’330 predicts that the thermal gain rate it computed in the past
`
`represents a speed a temperature inside the first location will change in response to
`
`changes in outside temperature at the current time or at a time in the future, for
`
`example, as per a weather forecast. Thus, when Ehlers ’330 computes its thermal
`
`gain rate, it is stored as a predicted thermal gain rate for a given setpoint and a given
`
`outside temperature, which may re-occur in the future.
`
` For example, with reference to Figure 3D, given an initial setpoint
`
`starting temperature of 72 degrees F, it can be predicted that when the HVAC
`
`system is OFF and not actively working to cool the structure, the inside temperature
`
`of the structure will change at about 1 degree F per hour when the outside
`
`temperature is 77 degrees F. However, if the outside temperature changes, to for
`
`
`
`22
`
`
`
`example, 99 degrees F, it can be predicted that the inside temperature will change
`
`at a speed of about 3.9 degrees F per hour. 2
`
`
`
`In this example, Ehlers ’330 uses such predictions to determine what
`
`future setpoint would result in a thermal gain rate that would not increase HVAC
`
`run time over a future period of time. The way in which Ehlers ’330 does this is
`
`further explained below with reference to the following exemplary diagram I have
`
`created:
`
`
`
`
`2 I note that as Ehlers ’330 explains, the rates of change illustrated by the straight
`lines in Figure 3D are “drawn to illustrate the rate of thermal gain” and “do not
`depict the rapid initial gain when the differential is large and the slower rate of
`thermal gain, which occurs as the indoor temperature reaches the outside
`temperature.” (Ex. 1004, ¶0253). Accordingly, the rates of change are illustrations
`only and in reality, when measured, would vary dynamically as the inside
`temperature changes. I use the above-recited values for illustrative purposes as
`Ehlers ’330 does.
`
`
`
`23
`
`
`
`Exemplary Thermosta�c Cycle Control of HVAC System, Ehlers ‘330
`Cooling Mode, based on Fig. 3G @ ~1:30 PM
`
`Cooling Cycle 68 min.
`
`OFF 45 min.
`
`RUN 23 min.
`33% Run Time
`
`Upper Temp. Control Limit
`
`Lower Temp. Control Limit
`23
`
`0
`
`45
`
`68
`Time in Minutes
`
`90
`
`113
`
`135
`
`78F
`
`76F
`
`Dead-band
`
`Inside Temperature
`
`74F
`
`Setpoint +
`2F Offset
`(computed)
`
`Setpoint 72F
`
`Example Diagram B
`
`
`
`
`
`In the case depicted above, the HVAC system is operating in cooling
`
`mode with an exemplary cooling cycle duration of 68 minutes. During this cycle,
`
`while the system is OFF, the inside temperature increases due to the effects of the
`
`(warmer) outside temperature, and while the system is on and running, the
`
`temperature decreases due to the cooling effects of the HVAC system. In this
`
`example, the system uses the learned thermal gain rates to predict that a 33% run
`
`time will be maintained if the setpoint is allowed to change to 74 degrees F3 because
`
`if the inside temperature changes by 2.7 degrees F/hour while the system is OFF,
`
`
`3 I have chosen a 2-degree computed offset as an example. (See, e.g., Ex. 1004,
`¶0256). I have also assumed a 2-degree “normal deadband.” (See, e.g., Ex. 1004,
`¶0255).
`
`
`
`24
`
`
`
`then the system need only run for 33% of the time to recover the indoor temperature
`
`to the original setpoint. In my opinion, given Ehlers ’330’s teachings, a POSITA
`
`would understand how to use Ehlers ’330’s thermal gain rates as well as other system
`
`data to calculate an appropriate setpoint offset, thereby calculating a new setpoint
`
`for the HVAC system. Specifically, using past performance data such as that
`
`illustrated in Figures 3D and 3E, a POSITA would understand how to calculate the
`
`setpoint that would maintain a particular HVAC runtime percentage given certain
`
`predicted indoor and outdoor temperature conditions by treating the setpoint as a
`
`variable.
`
` Second, Ehlers ’330 teaches that the thermal gain rates can be used to
`
`predict recovery time. Specifically, the system uses the thermal gain rates to
`
`calculate a first time at which a certain setpoint should be implemented in order to
`
`program the system to control the inside temperature to (i.e., recover) to that setpoint
`
`by a second time. (Ex. 1004, ¶¶0246, 0268, 0285, 0295, 0119, 0319, 0324-0325).
`
`This first time can be, for example, the time at which recovery must begin (e.g., the
`
`first setpoint must be implemented) to achieve that “occupied” setpoint by a
`
`particular time. In my opinion, the use of rates of change of inside temperature to
`
`determine the optimum time at which to begin recovery was well known in the art
`
`as of the relevant time. In my opinion, in view of Ehlers ’330’s teachings, a POSITA
`
`would understand how to use the thermal gain rates as well as other system
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