Patent Publication Number: US-7590499-B2

Title: Recording and conveying energy consumption and power information

Description:
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 11/427,161 entitled “Conveying Temperature Information in a Controlled Variable Speed Heating, Ventilation, and Air Conditioning (HVAC) System” and filed on Jun. 28, 2006, the entire disclosure of which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to measuring energy consumption of an electrical device and sending related information over a network. 
     BACKGROUND OF THE INVENTION 
     An air conditioning system is typically one of the high power consumption devices in a house or office building. With a traditional air-conditioning system that is controlled by a typical thermostat, the system typically cycles ON and OFF according to the differences of preset and measured temperature. The system draws a constant current or power when it is operating in the ON cycle. It essentially shuts off when in operating in the OFF cycle, and consequently no current or power is drawn from the electrical main circuit when it is operating in the OFF cycle. In order to estimate the energy consumption of the system, one may calculate the accumulated ON time and multiple it by the power consumption of the device to obtain the total energy consumption of the system. 
     With the above scenario, the energy (power) consumption of a device may be obtained from the specification or by a simple current meter. The same approach applies to week and month estimation of the energy consumption. However, the above approach may no longer hold if the compressor or motor is a variable speed device. For a variable speed compressor, the speed of the compressor may vary according to the differences of the ambient and set temperature. The power consumption varies with the speed of the motor/compressor and is no longer constant. Consequently, calculating the energy consumption of a device simply using ON/OFF duty cycle information from the thermostat is typically not adequate. 
     With the need to conserve electrical energy (power) usage, it is important for the actual electrical energy of an electrical device to be measured and reported. 
     SUMMARY OF THE INVENTION 
     The present invention provides apparatuses and methods that support measuring and conveying energy consumption by an electrical device. 
     With an aspect of the invention, an apparatus includes an energy sensor that measures an incremental energy value consumed by an electrical device during an incremental time duration. A processor obtains the incremental energy value, accumulates an energy usage measurement in accordance with the incremental energy value, provides requested information about energy consumption of the electrical device in response to a request from a network controller, and adjusts the energy usage measurement in accordance with the requested information. 
     With another aspect of the invention, an electrical device comprises a variable speed device. A logic control unit includes an array to provide at least one control signal to the variable speed device to control a speed of the variable speed device. A pulse width modulation controller controls a pulse width of the at least one control signal in accordance with a temperature difference and a feedback signal from the variable speed device. 
     With another aspect of the invention, the total energy consumption is partitioned into at least one energy component, in which the at least one energy component corresponds to the energy consumption of the electrical device during an associated time interval. The total energy consumption is adjusted by a transmitted value when a conformation is received. 
     With another aspect of the invention, a system includes a device control logic, which controls a variable speed device and sends energy consumption information to a network controller. The network controller may use the energy consumption information to determine a new set temperature for a thermostat unit that instructs the device control logic. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary of the invention, as well as the following detailed description of exemplary embodiments of the invention, is better understood when read in conjunction with the accompanying drawings, which are included by way of example, and not by way of limitation with regard to the claimed invention. 
         FIG. 1  shows a thermostat unit for controlling a variable speed compressor in accordance with an embodiment of the invention. 
         FIG. 2  shows a signal that is sent from a thermostat unit to a compressor controller unit for controlling a variable speed compressor in accordance with an embodiment of the invention. 
         FIG. 3  shows a compressor controller unit for controlling a variable speed compressor in accordance with an embodiment of the invention. 
         FIG. 4  shows a relationship between a temperature difference, referencing an ambient temperature to a set temperature, and a duty cycle of a signal in accordance with an embodiment of the invention. 
         FIG. 5  shows a relationship of a determined compression speed and the temperature difference in accordance with an embodiment of the invention. 
         FIG. 6  shows a flow diagram that is executed by the thermostat unit in accordance with an embodiment of the invention. 
         FIG. 7  shows a flow diagram that is executed by the compressor controller unit to initiate processing of the signal, as shown in  FIG. 2 . 
         FIG. 8  shows a flow diagram that is executed by the compressor controller unit to process the signal, as shown in  FIG. 2 , during a time period. 
         FIG. 9  shows an exemplary configuration for controlling a variable speed compressor. 
         FIG. 10  shows a control logic unit with current/power sensing in accordance with an embodiment of the invention. 
         FIG. 11  shows a control logic unit with an associated measurement unit for measuring energy consumption by a motor/compressor in accordance with an embodiment of the invention. 
         FIG. 12  shows a flow diagram for a logic controller when measuring and conveying information about energy consumption by an electrical device in accordance with an embodiment of the invention. 
         FIG. 13  shows an architecture of a system for measuring and conveying information about energy consumption in accordance with an embodiment of the invention. 
         FIG. 14  shows a flow diagram for a network controller when obtaining information about energy consumption from a control logic unit in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows a thermostat unit  100  for controlling a variable speed compressor (not shown) in accordance with an embodiment of the invention. Thermostat unit  100  includes microprocessor control unit (MCU)  107  and switching module  105 . Switching module  105 , which electrically turns on and off, may be implemented with a relay, triac, or field effect transistor (FET). Additionally, thermostat unit  100  may include keypad input  111  in order for a user to input a set temperature or a profile of set temperatures (as will be discussed) and display  113  to display the ambient temperature of a controlled space (e.g., a room) and the set temperature. 
     Microprocessor control unit  107  measures the ambient temperature of the controlled space with thermistor  109 , which is situated in an appropriate point of the controlled space. Microprocessor control unit  107  consequently determines a difference temperature (T diff ) by subtracting the set temperature (T set ) from the ambient temperature (T amb ):
 
 T   diff   =T   amb   −T   set   (EQ. 1)
 
     In the embodiment shown in  FIG. 1 , switching module  105  is either in the “on” state or the “off” state. When in the “on” state, electrical conductivity is completed from line  101  to line  103  and an AC waveform (typically 24 volts AC) is provided to a compressor (for cooling) to a furnace control board (for heating). When in the “off” state, electrical conductivity is blocked. In the following discussion, the thermostat is supporting the cooling function (i.e., by communicating with a compressor controller to control a compressor as will be discussed). 
     Because switching module  105  is either on or off, only two states are directly supported. However, in accordance with an aspect of the invention, information that is indicative of T diff  is transmitted from thermostat unit  100  to compressor controller unit  300  (as shown in  FIG. 3  by varying the duty cycle of a signal (e.g., signal  200  as shown in  FIG. 2 ) that is conveyed by lines  101 ,  103 . 
     In an embodiment of an invention, thermostat unit  100  sends a special signal that has a short pulse duration to notify a furnace/air conditioner controller to immediately stop operation. For example, the special signal can be four consecutive pulses with 1 second on and 1 second off. 
       FIG. 2  shows signal  200  that is sent from a thermostat unit  100  (as shown in  FIG. 1 ) to a compressor controller unit  300  (as shown in  FIG. 3 ) for controlling a variable speed compressor  303  (as shown in  FIG. 3 ) in accordance with an embodiment of the invention. Signal  200 , as shown in  FIG. 2 , spans a time duration over time periods  201 ,  203 , and  205 . 
     During each time period  201 ,  203 ,  205 , signal  200  is being electrically conducted during an activated time duration (T on ) (e.g., activated time duration  201   a  for time period  201 ) and electrically blocked during an deactivated time duration (T off ) (e.g., deactivated time duration  201   b  for time period  201 ). During activated time duration  201   a , AC power (corresponding to a 24 volts AC waveform) is conducted. During deactivated time duration  201   b , AC power is not conducted. The corresponding duty cycle is determined by: 
     
       
         
           
             
               
                 
                   Duty_Cycle 
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     In an embodiment of the invention, thermostat unit  100  notifies compressor unit  300  the value of T max  by sending a configuration signal having a preamble followed by a number of pulses, in which the number of pulses is indicative of the value of T max . In an exemplary embodiment, the preamble comprises a predetermined pulse sequence of two ON time periods followed by two OFF time periods, each time period being one second. For each ON time period, a pulse is generated for 0.5 second during an ON time period and not generated during an OFF time period. The value of T max  (degrees Fahrenheit) is determined from the number of pulses following the preamble by:
 
 T   max =2 (number of pulses+5)   (EQ. 3)
 
     Referring to  FIG. 1 , microprocessor control unit  107  controls switching module  105  to turn on and turn off signal  200  based on any period of time. (In fact, as suggested by  FIG. 2 , the time period may vary from one time period to another.) The time period may be 5, 10 or 15 minutes or any other time period. 
     The duty cycle of signal  200  conveys information about the temperature difference (T diff ) as determined by microprocessor control unit  107 . As suggested by  FIG. 2 , the duty cycle typically varies from one time period to another time period corresponding to temperature difference variations. 
     In an embodiment of the invention, the temperature difference (T diff ) is encoded by the duty cycle as follows:
 
Duty_Cycle= T   diff   /T   max *50%+50%  (EQ. 4)
 
Combining EQ. 4 and EQ. 2, one can determine the T on  by:
 
 T   on =( T   diff   /T   max *50%+50%)* T   cycle   (EQ. 5)
 
where  T   cycle   =T   on   +T   off  
 
However, if the temperature difference if greater than T max −Δ temp  or less than −T max +Δ temp , the temperature difference is limited as follows:
 
 T   diff   =T   max −1 if  T   diff   &gt;=T   max   −Δ   temp   (EQ. 6a)
 
 T   diff   =−T   max +1 if  T   diff   &lt;=−T   max   +Δ   temp   (EQ. 6b)
 
T max −Δ temp  corresponds to maximum value  409  of the duty cycle and −T max +Δ temp  corresponds to minimum value  407  of the duty cycle as shown in  FIG. 4 . The limit of |T diff | is reduced by one degree Fahrenheit in EQ. 6a and EQ. 6b so that the signal is not detected to be ON or OFF all of the time by compressor controller unit  300  when thermostat unit  100  is sending control information. (If signal  200  were ON or OFF all of the time, no signal transitions could be detected.)
 
       FIG. 3  shows compressor controller unit  300  for controlling a variable speed compressor  303  in accordance with an embodiment of the invention. Microprocessor control unit (MCU)  301  scans lines  101 ,  103  for signal  200  and detects a time between two rising signal edges (e.g., signal edges  251  and  253  as shown in  FIG. 2 ) to determine the current time period of signal  200 . Microprocessor control unit  301  may be coupled with a digital signal processor in order to facilitate calculations. 
     Referring to  FIG. 2 , when processing signal  200 , compressor controller unit  300  waits receives duty cycle information for an entire time period before further processing the information. For example, compressor controller unit  300  determines the duty cycle for time period  201  from signal  200  after detecting signal edge  253 . Compressor controller unit  300  consequently determines the temperature difference T diff , as measured by thermostat unit  100 , by decoding signal  200 . (As will be discussed with  FIG. 8 , compressor controller unit  300  utilizes flow diagram  800  to measure the duty cycle.) Compressor controller unit  300  measures the duty cycle of signal  200  of the previous time period in accordance with EQ. 2 and determines:
 
 T   diff =(Measured_Duty_Cycle−50%)/50%* T   max   (EQ. 7)
 
If T diff  is positive, variable speed compressor  303  should turn faster based on a predetermined relationship, e.g., relationship  503  as shown in  FIG. 5  as will be discussed. If T diff  is negative, variable speed compressor  303  should turn slower based on an algorithm.
 
     In an embodiment of the invention, compressor control unit  300  obtains T max  by a user entering T max  through keypad  309 . While compressor controller unit  300  may obtain the value of T max  from a configuration signal sent by thermostat unit  100 , as previously discussed, the value of T max  may be entered into keypad  111  by the user. Other embodiments of the invention may utilize a predetermined value of T max  that is stored in memory. 
     Microprocessor control unit  301  may access lookup data structure  317  in order to determine the temperature difference (T diff ) and the compressor speed. (As will be discussed, the compressor speed is determined as a function of the temperature difference as shown in  FIG. 5 .) In order to obtain a desired efficiency, compressor  303  typically runs at a higher speed as the temperature difference becomes greater. When the compressor speed has been determined, microprocessor control unit  301  instructs PWM (pulse width modulated) controller  305  to drive IGBT (insulated-gate bipolar transistor) array  307  (via bus  311 ) so that compressor  303  runs at the desired compressor speed (over bus  313 ). PWM controller  305  is provided an indication of the actual compressor speed over feedback connection  315  in order to adjust the compressor speed to obtain the desired compressor speed. An exemplary embodiment will be further discussed with  FIG. 9 . 
     With the exemplary embodiment, compressor controller unit  300  functions with a traditional thermostat design but with software modifications as will be discussed. 
       FIG. 4  shows relationship  405  between temperature difference (T diff )  403 , referencing an ambient temperature (of an environmentally controlled space where thermistor  109  is located) to a set temperature, and measured duty cycle  401  of a signal in accordance with an embodiment of the invention. In the embodiment shown in  FIG. 4 , relationship  405  is in accordance with EQ. 7, although other embodiments may utilize a different relationship between the temperature difference and the duty cycle. In the example shown in  FIG. 4 , if measured duty cycle  401  equals 25%, temperature difference  403  is determined to equal −0.5T max . 
     As previously discussed, a duty cycle between minimum value  407  and maximum value  409  is utilized in order to facilitate the detection of signal edges by microprocessor control unit  301 . In an embodiment of the invention, microprocessor control unit  301  analyzes signal  200  in a time-interrupt basis as shown in  FIG. 8 . Depending on the value of the time interval between interrupts, microprocessor control unit  301  may not detect a transition of signal  200 . (Between time-interrupts, microprocessor control unit  301  may be executing other tasks, e.g., diagnostics and executing commands entered through keypad  309 .) Consequently, the temperature difference is limited between T max −Δ temp  and −T max +Δ temp  so that signal transitions can be detected. As the time durations between time-interrupts become smaller, the value of |Δ temp | becomes smaller. If microprocessor control unit  301  processes time-interrupts quickly enough, Δ temp  is essentially zero. 
       FIG. 5  shows relationship  503  of a determined compression speed  501  and the temperature difference  403  in accordance with an embodiment of the invention. Microprocessor control unit  301  measures duty cycle  401  and determines temperature difference  403  using relationship  405 . In an embodiment of the invention, microprocessor control unit  301  accesses lookup data structure  317  using an address determined by duty cycle  401  to obtain temperature difference  403 . Microprocessor control unit  301  subsequently accesses lookup data structure  317  to determine compression speed  501  using an address determined by temperature difference  403  to obtain compression speed  501 . Because the temperature difference typically varies from time period to time period, as suggested by  FIG. 2 , compressor speed  501  consequently varies. 
       FIG. 6  shows flow diagram  600  that is executed by microprocessor control unit  107  in accordance with an embodiment of the invention. Microprocessor control unit  107  obtains the set temperature T set , the time period (T cycle ), and the ambient temperature (T room ) from thermistor  109  in step  601 . In step  603 , microprocessor control unit  107  determines the temperature difference (T diff ) in accordance with EQ. 1. If the temperature difference is larger than the maximum temperature difference (T max ), as determined by step  605 , the temperature difference is limited to T max −1 as determined by step  607 . Otherwise, step  611  determines whether the temperature difference is less than the negative maximum temperature difference (−T max ) in step  611 . If so, the temperature difference is limited to −T max +1 in step  613 . Otherwise, the activated time duration (T on ) is determined in accordance with EQ. 5 in step  609 . Signal  200  is generated in accordance with T on  and T off  as determined by flow diagram  600 . 
       FIG. 7  shows flow diagram  700  that is executed by compressor controller unit  300  to initiate processing of signal  200 , as shown in  FIG. 2 , during a time period. Microprocessor control unit  301  obtains T max  and F def  to initiate processing over the current time period. Consequently, microprocessor control unit  301  resets T on , T off , and sets the compressor speed variable F speed  to F def  in step  701 . In step  702 , microprocessor control unit  301  determines whether signal  200  is present (i.e., whether any signal transitions have been detected.) In step  703 , interrupts are configured to occur periodically (every T interrupt  time interval) so that pulse edges can be detected. For example, if the minimum pulse duration is 1 second (corresponding to an emergency stop), interrupts are configured to occur at least every 0.5 seconds. As will be discussed, procedure  800  (as shown in  FIG. 8 ) is processed every T interrupt  time interval. 
       FIG. 8  shows flow diagram  800  that is executed by compressor controller unit  300  to process signal  200 , as shown in  FIG. 2 , during a time period. In the following discussion, one should note that flow diagram  800  determines whether there are signal edges detected in signal  200 . If not, compressor  303  is not active. 
     In step  801 , microprocessor control unit  301  determines if signal  200  is conducting AC power (typically 24 volts AC) during T on . If not, the T off  counter is incremented in step  817 . (In flow diagram  800 , T off  counter and T on  counter are appropriately incremented so that the duty cycle can be determined when flow diagram is respectively executed during the current timer period. Once the current time period is completed, the duty cycle is determined by step  807  as will be discussed.) The process will exit (i.e., flow diagram  800  determines that the air conditioner is not active). 
     If microprocessor control unit  301  determines that signal  200  is conducting AC power during T on  in step  801 , microprocessor control unit  301  determines if signal  200  was previously in a non-conductive state (i.e., deactivated time duration  201   b  for time period  201 ) in step  805 . If not, the T on  counter is incremented in step  819 , and process  800  is exited. If so, a rising signal edge is detected and step  807  is executed. 
     In step  807  (corresponding to a rising edge just being detected), the temperature difference is determined in accordance with EQ. 7 for the time period that has just completed. The T on  counter and the T off  counter are then reset. In step  811 , microprocessor control unit  301  determines the speed of compressor  303  in accordance with a predetermined function ƒ(T diff ), e.g., relationship  503  as shown in  FIG. 5 . In step  813 , the compressor speed F speed  is adjusted, in which microprocessor control unit  301  provides the updated compressor speed to PWM controller  305 . Compressor  303  is consequently instructed to change its speed through bus  311 , IGBT array  307 , and bus  313 . 
       FIG. 9  shows an exemplary configuration for controlling variable speed compressor  303 . In the exemplary embodiment, compressor  303  comprises a three-phase motor; however, other embodiments may support other types of motors, e.g., single-phase induction motors, DC motors, and universal motors. 
     Compressor  303  is powered by AC power lines  905   a ,  905   b  through rectifier bridge  907  and IGBT array  307 . PWM controller  305  configures IGBT array  307  to control compressor  303  at the desired compressor speed. PWM controller  305  includes microcontroller  901  and gate drivers  903   a - 903   c . The speed of compressor  303  is controlled by PWM controller  305 , in which the voltage-to-frequency ratio is adjusted with a speed feedback configuration. 
     Embodiments of the invention support a heating function in a HVAC system. When supporting the heating function a controller unit, in conjunction with a thermostat unit, couples with a variable blower motor of a furnace. The speed of the variable blower motor is varied in accordance with characteristics of the motor and thermodynamics considerations. 
       FIG. 10  shows a control logic unit  1000  with current/power sensing in accordance with an embodiment of the invention. Control logic unit  1000  controls a speed of motor or compressor (as previously discussed) through AC-DC inverter  1003  and array  1005 . (In the embodiment shown in  FIG. 10 , processor  1001  controls both the speed of a variable speed device as well as determine the energy consumption of the variable speed device.) Control logic unit  1000  includes power measurement circuit  1007  that is integrated with motor control logic. For example, circuit  1007  may include a high power, low value resistor. Processor  1001  obtains a power measurement from power measurement circuit  1007  for an incremental time duration (e.g., 1 msec). Because the incremental time duration ΔT is sufficiently small, the power utilization P i  is approximately constant, and thus the incremental energy consumption ΔE i  during the i th  time interval for a controlled device (not shown in  FIG. 10 ) is determined by:
 Δ E   i   =P   i   ΔT   EQ. 8 
     Power measurement circuit  1007  may indirectly measure the power utilization of a controlled device by measuring the electrical current (I). For example, if the real component (R) of the controlled device&#39;s impedance is known, processor  1001  may determine power utilization by multiplying the I 2  by R. 
     Processor  1001  accumulates the total energy consumption by adding the incremental values of energy consumption using: 
     
       
         
           
             
               
                 
                   
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     Processor  1001  may further partition the total energy consumption so that energy components E j  of the total energy consumption are maintained corresponding to different time intervals (e.g., peak hours) and different days (e.g., weekends versus weekdays). For example, 
     
       
         
           
             
               
                 
                   
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     By multiplying the measured power by the incremental time duration and summing the products, the total energy consumption of the controlled device (e.g., motor or compressor) over a recorded time period is determined. 
     Processor  1001  continues to add the incremental energy consumption ΔE i  to the previous value of the total energy consumption to update the total energy consumption. The total energy consumption is accumulated until a valid and successful transmission of the requested information to network controller  1301  (as shown in  FIG. 13 ) through network interface  1009  occurs. 
     Network interface  1009  may interface to various types of networks including landline, cable, satellite, and terrestrial wireless networks. 
     The network controller may request that the total energy consumption be reported by control logic unit  1000 . Also, with embodiments of the invention, specific energy components may be requested from control logic unit  1000  by the network controller. For example, the network controller may request the energy consumption of the controlled device during peak hours on a Friday. 
     With embodiments of the invention, accumulation of the energy consumption continues until processor  1001  receives an acknowledgment (feedback) from the network controller that the transmission with the requested information was successful. Processor  1001  subsequently deducts the value of the energy consumption that was transmitted. Once control logic unit  1000  receives a confirmation, processor  1001  deducts the value of the energy consumption (e.g., a specified energy component) that was transmitted to the network controller. 
     With embodiments of the invention, the network controller (e.g., network controller  1301 ) provides an acknowledgment with the received value of the energy consumption to control logic unit  1000 . If the received value in the acknowledgment is consistent with the value sent to the network controller, processor  1001  deducts the received value from the total energy consumption of the controlled device. The acknowledgment may comprise a fixed code or codes with the returned value as a verification mechanism of the transmitted value. 
       FIG. 11  shows control logic unit  1100  with associated measurement unit  1107  for measuring energy consumption by a motor/compressor in accordance with an embodiment of the invention. As illustrated in  FIG. 11 , control logic unit  1100  is physically separate from an associated unit comprising measurement unit  1107  and network interface  1109 . Processor  1101  controls the speed of a controlled device (not shown in  FIG. 11 ) in accordance with the previous discussion. Measurement unit  1107  accumulates the total energy consumption until requested by a network controller through network interface  1109 . When a request is received, measurement unit  1107  adjusts the total energy consumption in accordance with the previous discussion. 
       FIG. 12  shows flow diagram  1200  for logic controller  1000  when measuring and conveying information about energy consumption by an electrical device in accordance with an embodiment of the invention. In step  1201 , processor  1001  determines whether to update the total energy consumption. If so, processor  1001  obtains the incremental power utilization from power measurement circuit  1007 , determines the incremental energy consumption, and adds the incremental energy consumption to the previous value of the total energy consumption in step  1203 . 
     If the network controller has requested energy consumption information, as determined by step  1205 , processor  1001  transmits the requested information to network controller in step  1207 . If a confirmation is received from the network controller, as determined by step  1209 , processor  1001  adjusts the value of the total energy consumption by the transmitted value in step  1211 . 
       FIG. 13  shows an architecture of system  1300  for measuring and conveying information about energy consumption in accordance with an embodiment of the invention. System  1300  includes control logic unit  1000  (which controls the speed of a controlled device), network controller  1301 , and thermostat unit  1303  (which instructs control logic unit  1000  in accordance with previous discussions). 
     Control logic unit  1000  measures the total energy consumption of controlled device  1305  and reports requested information about consumed energy when requested by network controller  1301 . For example, network controller  1301  may obtain the energy consumption of device  1305  during a peak hour. 
     Network controller  1301  may further determine that the temperature set needs to be adjusted in order to reduce the projected energy consumption of electrical device  1305  in order to reduce energy costs. If so, network controller  1301  sends a new set temperature value to thermostat unit  1303 . Consequently, thermostat unit  1303  instructs control logic unit  1000  to controlled device  1305  in accordance with the new set temperature using EQs. 1-7 as previously discussed. 
       FIG. 14  shows flow diagram  1400  for network controller  1301  when obtaining information about energy consumption from control logic unit  1000  in accordance with an embodiment of the invention. In step  1401  network controller  1301  requests a requested energy component from control logic unit  1000  and receives the requested information in step  1403 . Network controller  1301  may specify a time and date (e.g., peak hour during the week) in the request. 
     In step  1405 , network controller  1301  may further determine a new set temperature based on the value of the energy consumption that is received from control logic unit  1000 . For example, network controller  1301  may determine that controlled device  1305  is using an amount of energy that exceeds an target limit. Consequently, network controller  1301  may provide a new set temperature to thermostat  1302  in step  1407 . 
     As can be appreciated by one skilled in the art, a computer system with an associated computer-readable medium containing instructions for controlling the computer system can be utilized to implement the exemplary embodiments that are disclosed herein. The computer system may include at least one computer such as a microprocessor, digital signal processor, and associated peripheral electronic circuitry. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.