Patent Publication Number: US-8116911-B2

Title: System and method for sump heater control in an HVAC system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND 
     Heating, ventilation, and air conditioning systems (HVAC systems) are used in residential and/or commercial areas for heating and/or cooling to create comfortable temperatures inside those areas. These temperature controlled areas may be referred to as comfort zones. Comfort zones may comprise different zone conditions (i.e., temperature, humidity, etc.) and the locations in which the HVAC systems are installed or otherwise associated with for the purpose of performing heat exchange (sometimes referred to as an ambient zone) may also have different conditions. Both the zone conditions and the conditions of the location affect operation of the HVAC systems and, where the conditions are different, may result in otherwise substantially similar HVAC systems operating at different efficiencies. Some HVAC systems are heat pump systems. Heat pump systems are generally capable of cooling a comfort zone by operating in a cooling mode for transferring heat from a comfort zone to an ambient zone using a refrigeration cycle (i.e., Rankine cycle). When the temperature of an ambient zone in which a portion of an HVAC system is installed or otherwise associated with is colder than the temperature of a comfort zone with which the HVAC system is associated, the heat pump systems are also generally capable of reversing the direction of refrigerant flow (i.e., a reverse-Rankine cycle) through the components of the HVAC system so that heat is transferred from the ambient zone to the comfort zone (a heating mode), thereby heating the comfort zone. 
     One example of rating the cooling energy efficiency of an HVAC system is the use of the Seasonal Energy Efficiency Ratio (SEER) rating. To obtain a SEER rating, the HVAC system is tested under prescribed conditions (i.e., certification conditions) to determine the efficiency at which it generates an energy output based on an energy input. The prescribed conditions generally involve very strict control over the zone conditions and the ambient conditions of the location of the installation of the HVAC system being tested. A higher SEER rating is indicative of a more energy efficient HVAC system. The higher SEER rating indicates that the HVAC system may be operated at a lower energy cost than an HVAC system having a lower SEER rating. 
     SUMMARY OF THE DISCLOSURE 
     In one embodiment, a method is provided that includes powering up a heating, ventilation, and air conditioning system and operating a sump heater for a compressor for a first predetermined period of time in response to the heating, ventilation, and air conditioning system being powered up. 
     In another embodiment, a heating, ventilation, and air conditioning system is provided that includes a compressor, a sump heater associated with the compressor, and a controller configured to control the compressor and the sump heater so that the sump heater is not operated while the compressor is operated. 
     The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments of the disclosure, and by referring to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. 
         FIG. 1  is a simplified block diagram of an HVAC system according to embodiments of the disclosure; 
         FIG. 2  is a simplified block diagram of a controller of the HVAC system of  FIG. 1  according to embodiments of the disclosure; 
         FIG. 3  is a schematic flow chart that illustrates a method of operating the HVAC system of  FIG. 1  according to the disclosure; and 
         FIG. 4  illustrates a general-purpose processor (e.g., electronic controller or computer) system suitable for implementing the several embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a simplified schematic diagram of a heating/ventilation/air conditioning system  100  (hereinafter referred to as an “HVAC system  100 ”) according to an embodiment. The HVAC system  100  operates to selectively control the temperature, humidity, and/or other air quality factors of a comfort zone  102 . The HVAC system  100  generally comprises an ambient zone unit  104  and a comfort zone unit  106 . The ambient zone unit  104  comprises a compressor  108 , an ambient zone heat exchanger  110 , and an ambient zone fan  112 . The comfort zone unit  106  comprises a restriction device  114 , a comfort zone heat exchanger  116 , and a comfort zone blower  118 . Refrigerant is carried between the compressor  108 , the ambient zone heat exchanger  110 , the restriction device  114 , and the comfort zone exchanger  116  through refrigerant tubes  120 . 
     The comfort zone blower  118  forces air from the comfort zone  102  into contact with the comfort zone heat exchanger  116 , and subsequently back into the comfort zone  102  through air ducts  122 . Similarly, the ambient zone fan  112  forces air from an ambient zone  124  into contact with the ambient zone heat exchanger  110  and subsequently back into the ambient zone  124  along an ambient air flow path  126 . The HVAC system  100  is generally controlled by interactions between a controller  128  and a communicating thermostat  130 . The controller  128  comprises a controller processor  132  and a controller memory  134  while the communicating thermostat  130  comprises a thermostat processor  136  and a thermostat memory  138 . 
     Further, the controller  128  communicates with an ambient zone temperature sensor  140  while the communicating thermostat  130  communicates with a comfort zone temperature sensor  142 . In this embodiment, communications between the controller  128  and the communicating thermostat  130 , the controller  128  and the ambient zone temperature sensor  140 , and the communicating thermostat  130  and the comfort zone temperature sensor  142  are capable of bidirectional communication. Further, communications between the controller processor  132  and the controller memory  134  and between the thermostat processor  136  and the thermostat memory  138  are capable of bidirectional communication. However, in alternative embodiments, the communication between some components may be unidirectional rather than bidirectional. 
     The HVAC system  100  is called a “split-system” because the compressor  108 , the ambient zone heat exchanger  110 , and the ambient zone fan  126  are colocated in the ambient zone unit  104  while the restriction device  114 , comfort zone heat exchanger  116 , and comfort zone blower  118  are colocated in the comfort zone unit  106  separate from the ambient zone unit  104 . However, in alternative embodiments of an HVAC system, substantially all of the components of the ambient zone unit  104  and the comfort zone unit  106  may be colocated in a single housing in a system called a “package system.” Further, in alternative embodiments, an HVAC system may comprise heat generators such as electrically resistive heating elements and/or gas furnace elements so that a comfort zone heat exchanger and the heat generators are both in a shared airflow path of a comfort zone blower. 
     While the comfort zone  102  may commonly be associated with a living space of a house or an area of a commercial building occupied by people, the comfort zone  102  may be also be associated with any other area in which it is desirable to control the temperature, humidity, and/or other air quality factors (i.e. computer equipment rooms, animal housings, and chemical storage facilities). Further, while the comfort zone unit  106  is shown as being located outside the comfort zone  102  (i.e. within an unoccupied attic or crawlspace), the comfort zone unit may alternatively be located within or partially within the comfort zone  102  (i.e. in an interior closet of a building). 
     Each of the ambient zone heat exchanger  110  and the comfort zone heat exchanger  116  may be constructed as air coils, shell and tube heat exchangers, plate heat exchangers, regenerative heat exchangers, adiabatic wheel heat exchangers, dynamic scraped surface heat exchangers, or any other suitable form of heat exchanger. The compressor  108  may be constructed as any suitable compressor, for example, a centrifugal compressor, a diagonal or mixed-flow compressor, an axial-flow compressor, a reciprocating compressor, a rotary screw compressor, a rotary vane compressor, a scroll compressor, or a diaphragm compressor. In this embodiment, the compressor  108  is capable of operating in multiple stages (e.g., stage A and stage B). More specifically, the compressor  108  comprises a compressor A  108   a  (for stage A) and a compressor B  108   b  (for stage B). Alternative embodiments of an HVAC system may comprise one or more compressors that are operable at more than one speed or at a range of speeds (i.e., a variable speed compressor). 
     Further, while the HVAC system  100  is shown as operated in a cooling mode to remove heat from the comfort zone  102 , the HVAC system  100  is configured as a “heat pump” system that selectively allows flow of refrigerant in the direction shown in  FIG. 1  to cool the comfort zone  102  or in the reverse direction to that shown in  FIG. 1  to heat the comfort zone  102  in a heating mode. It will further be appreciated that in alternative embodiments, a second restriction device substantially similar to restriction device  114  may be incorporated into an ambient zone unit to assist with operation of an HVAC system in a heating mode substantially similar to the heating mode of HVAC system  100 . 
     In the cooling mode, the compressor  108  operates to compress low pressure gas refrigerant into a hot and high pressure gas that is passed through the ambient zone heat exchanger  110 . As the refrigerant is passed through the ambient zone heat exchanger  110 , the ambient zone fan  112  operates to force air from the ambient zone  124  into contact with the ambient zone heat exchanger  110 , thereby removing heat from the refrigerant and condensing the refrigerant into high pressure liquid form. The liquid refrigerant is then delivered to the restriction device  114 . Forcing the refrigerant through the restriction device  114  causes the refrigerant to transform into a cold and low pressure gas. The cold gas is passed from the restriction device  114  into the comfort zone heat exchanger  116 . While the cold gas is passed through the comfort zone heat exchanger  116 , the comfort zone blower  118  operates to force air from the comfort zone  102  into contact with the comfort zone heat exchanger  116 , heating the refrigerant and thereby providing a cooling and dehumidifying effect to the air, which is then returned comfort zone  102 . In this embodiment, the HVAC system is using a vapor compression cycle, namely, the Rankine cycle. In the heating mode, generally, the direction of the flow of the refrigerant is reversed (compared to that shown in  FIG. 1 ) so that heat is added to the comfort zone  102  using a reverse-vapor compression cycle, namely, the reverse-Rankine cycle. It will be appreciated that alternative embodiments of an HVAC system may use any other suitable thermodynamic cycle for transferring heat to and/or from a comfort zone. 
     Generally, the controller  128  communicates with the ambient zone temperature sensor  140  that is located in the ambient zone  124  (i.e. outdoors, outdoors within the ambient zone unit in an embodiment where the ambient zone unit is located in the ambient zone, adjacent the ambient zone unit in an embodiment where the ambient zone unit is located in the ambient zone, or any other suitable location for providing an ambient zone temperature or a temperature associated with the ambient zone). While the controller  128  is illustrated as positioned within the ambient zone unit  104 , in alternative embodiments, the controller  128  may be positioned adjacent to but outside an ambient zone unit, outside a comfort zone, within a comfort zone unit, within a comfort zone, or at any other suitable location. It will be appreciated that in alternative embodiments, an HVAC system may comprise a second controller substantially similar to controller  128  and that the second controller may be incorporated into a comfort zone unit substantially similar to comfort zone unit  106 . In the embodiment shown in  FIG. 1 , through the use of the controller processor  132  and the controller memory  134 , the controller  128  is configured to process instructions and/or algorithms that generally direct the operation of the HVAC system  100 . 
     The HVAC system  100  further comprises a sump heater  109  associated with the compressor  108 . The sump heater  109  operates to heat an interior sump portion of the compressor  108  (in this embodiment, one or more sump heaters may be used to heat an interior sump portion of each compressor  108   a  and compressor  108   b  when sump heat is operated, in which case they would be denoted  109   a  for compressor  108   a , and  109   b  for  108   b ). The sump heater  109  operates to vaporize liquid refrigerant when liquid refrigerant is present in the sump portion of the compressor  108 . In this embodiment, the sump heater  109  is constructed of one or more electrically resistive heating elements. However, in alternative embodiments, the sump heater  109  may be constructed in any manner suitable for causing the vaporization of liquid refrigerant within the compressor  108 . 
     The sump heater  109  of the HVAC system  100  can be controlled in many different ways by the controller  128  dependent upon the instructions and/or algorithms the controller  128  executes. In some cases, the HVAC system  100  may be controlled by controller  128  in a manner that operates or prevents operation of the sump heater  109  during a ratings certification test (such as a test for assigning a SEER value) for the HVAC system  100 . Since operating the sump heater  109  consumes energy, unnecessary operation of the sump heater  109  is directly correlated to a lower energy efficiency rating (such as a SEER rating). One example of undesired operation of the sump heater  109  is operating the sump heater  109  during operation of the compressor  108 . 
     Accordingly, the present disclosure provides systems and methods of reducing unwanted operation of the sump heater  109  by enabling the controller  128  to control operation of the sump heater  109  in an efficient manner. Specifically, in some cases, the controller  128  prevents simultaneous operation of the sump heater  109  and the compressor  108 . Further, in some cases, the controller  128  prevents operation of the sump heater  109  when the temperature of the ambient zone  124  is above a predetermined temperature. Still further, in some cases, the controller  128  selectively operates the sump heater  109  when the compressor  108  has not operated for a predetermined period of time and the ambient zone  124  temperature is below a predetermined temperature. 
     Each of the above described conditions of operating the sump heater  109  may potentially provide more efficient operation of the HVAC system as a whole, thereby possibly resulting in a higher energy efficiency rating. The systems and methods of achieving such increased energy efficiency ratings due to selective operation of the sump heater  109  are described in more detail below. 
     Referring now to  FIG. 2 , the controller  128  is shown in greater detail. The controller  128  is used to control the different components of the HVAC system  100 . The controller  128  further comprises a personality module  144  that stores information about the HVAC system  100  and the components thereof. The controller  128  retrieves information stored on the personality module  144  and gives instructions to the controller processor  132  and controller memory  134  based on the information provided by the personality module  144 . The controller processor  132  and controller memory  134  comprise and/or operate to provide any necessary logical state indicators, keys, memories, timers, flags, counters, pollers, monitors, callers, and status indicators for processing and/or performing any programs, instructions, and/or algorithms provided to the controller  128 . 
     The controller  128  comprises a plurality of algorithm status variables, specifically, a sump heater status  146  and a compressor status  148 . The sump heater status  146  yields a positive result when the sump heater  109  is operating and yields a negative result when the sump heater  109  is not operating. In other words, the sump heater status  146  indicates whether the sump heater  109  is being operated to heat the sump portion of the compressor  108 . If more than one heater is used and controlled independently, then more than one status will be needed (i.e. sump heater status  146   a  would correspond to sump heater  109   a  operation,  146   b  to  109   b , and so forth). The compressor status  148  yields a positive result when the compressor  108  (in this case, either compressor  108   a  or compressor  108   b ) is being operated and yields a negative result when the compressor  108  is not operating (in this case, neither the compressor  108   a  nor the compressor  108   b ). For independent sump heat control, then likewise more than one compressor status will be needed. 
     The controller  128  further comprises a plurality of stored variables, specifically, an InitialTimeLimit  150 , a CompOnTimeLimit  152 , a HighTempLimit  154 , a TempDelta  156 , and a CompAbsenceLimit  158 . The variables InitialTimeLimit  150 , CompOnTimeLimit  152 , and CompAbsenceLimit  158  each store a time value while the variables HighTempLimit  154  and TempDelta  156  each store temperature values. The temperature variables are configurable to represent and/or store temperatures in degrees Fahrenheit (° F.), degrees Celsius (° C.), Kelvin (K), or degrees Rankine (° R), however this embodiment uses degrees Fahrenheit. 
     In this embodiment, InitialTimeLimit  150  stores a value of 10 hours. However, in alternative embodiments an InitialTimeLimit may store any other suitable time value within a range of about 5 hours to about 20 hours. 
     Further in this embodiment, CompOnTimeLimit  152  stores a value of 4 minutes. However, in alternative embodiments a CompOnTimeLimit may store any other suitable time value within a range of about 1 minute to about 10 minutes. 
     Still further, CompAbsenceLimit  158  stores a value of 30 minutes. However, in alternative embodiments a CompAbsenceLimit may store any other suitable time value within a range of about 25 minutes to about 120 minutes. 
     In this embodiment, HighTempLimit  154  stores a value of 85° F. However, in alternative embodiments, a HighTempLimit may store any other suitable temperature value within a range of about 70° F. to about 90° F. 
     Similarly, TempDelta  156  stores a value of 10° F. However, in alternative embodiments, a TempDelta may store any other suitable temperature value within a range of about 5° F. to about 20° F. 
     Still referring to  FIG. 2 , the controller  128  further comprises a plurality of timers, specifically, a CompOn Timer  160 , a CompOff Timer  162 , and a SumpHeaterOn Timer  164 . The CompOn Timer  160  is a timer configured to selectively store and report a cumulative length of time compressor  108  has run since the CompOn Timer  160  was last reset to zero. The CompOff Timer  162  is a timer configured to selectively store and report a cumulative length of time compressor  108  has been inactive (not operated) since the CompOff Timer  162  was last reset to zero. The SumpHeaterOn Timer  164  is a timer configured to selectively store and report a cumulative length of time sump heater  109  has run since the SumpHeaterOn Timer  164  was last reset to zero. 
     In this embodiment, the values for the InitialTimeLimit  150 , the CompOnTimeLimit  152 , the HighTempLimit  154 , the TempDelta  156 , and the CompAbsenceLimit  158  are provided to the controller  128  from the personality module  144 . In alternative embodiments of an HVAC system, the values for a InitialTimeLimit, a CompOnTimeLimit, a HighTempLimit, a TempDelta, and/or a CompAbsenceLimit may be selected by a user, hard coded into a controller, or provided in any other suitable manner. 
     Referring now to  FIG. 3 , a flow chart of a method  300  of operating an HVAC system such as HVAC system  100  is shown. The method  300  is hereinafter described by detailing a plurality of states of operation and explaining what conditions are met to allow and/or cause transition from one state to another. 
     When the HVAC system  100  has not yet been powered up or where power to the HVAC system  100  is being cycled and is powered down, the HVAC system  100  is inactive as represented by state  302 . When power is applied to the HVAC system  100 , the controller  128  polls the compressor status  148  to determine whether the compressor  108  is on or off and method  300  exits state  302  to proceed with either path condition  304  or condition  308 , respectively. At condition  304 , if the compressor  108  is on at power up, the method  300  starts the CompOn Timer  160  and the HVAC system  100  is then operating in state  306  where the compressor  108  is on but the sump heater  109  is off. 
     However, if the controller  128  determines that the compressor  108  is off after initialization of HVAC system  100 , thereby meeting the condition  308 , the method  300  turns on the sump heater  109  and starts the SumpHeaterOn Timer  164 , leaving the HVAC system  100  operating in state  310  where the compressor  108  is off and the sump heater  109  is on. 
     If the HVAC system  100  is operating in state  306  and the compressor  108  turns off, the method  300  will exit state  306  to proceed with either path condition  312  or condition  320  according to the CompOn Timer  160 . At condition  312 , the method  300  turns on the sump heater and stops the CompOn Timer  160 , leaving the HVAC system  100  operating in state  310 . 
     While operating in state  310 , if the compressor  108  turns on, the method  300  will exit state  310  to proceed with either path condition  314  or condition  316 . If the compressor  108  is on, at condition  314 , the method  300  starts the CompOn Timer  160  and turns off the sump heater  109 , leaving the HVAC system  100  operating in state  306  as previously described. 
     However, if while operating in state  310 , the method  300  determines at condition  316  that the value of the SumpHeaterOn Timer  164  is greater than the InitialTimeLimit  150 , the HVAC system  100  is then operating at state  318  where the compressor  108  is off and the sump heater  109  is on. 
     However, if the HVAC system  100  were operating in state  306  and the method  300  determined at condition  320  that the value of the CompOn Timer  160  was greater than the value of the CompOnTimeLimit  152 , the method  300  stops the SumpHeaterOn Timer  164 , leaving the HVAC system  100  operating in the state  322  where the compressor  108  is on and the sump heater  109  is off. 
     If the HVAC system  100  is operating in state  318  the method  300  will exit state  318  to proceed with either path condition  324 , condition  326 , or condition  332 . If the compressor  108  turns on, this is condition  324 , and the method  300  turns off the sump heater  109  and starts the CompOn Timer  160 , leaving the HVAC system  100  operating in state  322 . 
     If, however, the HVAC system  100  is operating in state  318  and the method  300  determines at condition  326  that the temperature of the ambient zone  124  (as reported by the ambient zone temperature sensor  140 ) is greater than or equal to the HighTempLimit  154 T the method  300  turns off the sump heater  109 , leaving the HVAC system  100  operating in state  328  where the compressor  108  is off and the sump heater  109  is also off. However if the temperature of the ambient zone  124  is between HiTemp Limit  154  minus TempDelta  156  and the HiTemp Limit  154 , the path is condition  332  and method  300  will turn off the sump heater  109  and start CompOff Timer  162  before leaving the HVAC system  100  in state  328 . 
     While the HVAC system  100  is operating in state  328  the method  300  will exit state  328  to proceed with either path condition  330 , condition  338 , or condition  340 . If at condition  330  the ambient zone  124  temperature is determined to be less than HighTempLimit  154  minus TempDelta  156  and the CompOff Timer  162  is greater than the CompAbsence Limit  158 , the method  300  turns on the sump heater  109 , leaving the HVAC system  100  operating in state  318 . Similarly, while the HVAC system  100  is operating in state  328 , if at condition  330  the ambient zone temperature sensor  140  is determined to be faulted (nonoperational), the method  300  turns on the sump heater  109 , leaving the HVAC system  100  operating in state  318 . 
     While the HVAC system  100  is operating at state  328 , if at condition  338  the method  300  determines that the CompOff Timer  162  is less than or equal to the CompAbsenceLimit  158 , the HVAC system  100  continues to operates at state  328 . 
     However, if while the HVAC system  100  is operating in state  328  and at condition  340  the compressor  108  turns on, the method  300  starts the CompOn Timer  160  and stops the CompOff Timer  162 , leaving the HVAC system  100  operating in state  322 . 
     With the HVAC system  100  operating at state  322  the method  300  will exit state  322  only to proceed with condition  334 . If the compressor  108  turns off at condition  334 , the method  300  starts the CompOff Timer  162 , leaving the HVAC system  100  operating in state  328  where the compressor  108  is off and the sump heater  109  is off. 
     It is according to the above-described conditions of method  300  that the method  300  controls the operation of HVAC system  100  in the various above-described states of method  300 . 
     Referring now to  FIG. 4 , the HVAC system  100  described above comprises a processing component (such as processors  132  or  136  shown in  FIG. 1 ) that is capable of executing instructions related to the actions described previously. The processing component may be a component of a computer system.  FIG. 4  illustrates a typical, general-purpose processor (e.g., electronic controller or computer) system  1300  that includes a processing component  1310  suitable for implementing one or more embodiments disclosed herein. In addition to the processor  1310  (which may be referred to as a central processor component or CPU), the system  1300  might include network connectivity devices  1320 , random access memory (RAM)  1330 , read only memory (ROM)  1340 , secondary storage  1350 , and input/output (I/O) devices  1360 . In some cases, some of these components may not be present or may be combined in various combinations with one another or with other components not shown. These components might be located in a single physical entity or in more than one physical entity. Any actions described herein as being taken by the processor  1310  might be taken by the processor  1310  alone or by the processor  1310  in conjunction with one or more components shown or not shown in the drawing. 
     The processor  1310  executes instructions, codes, computer programs, or scripts that it might access from the network connectivity devices  1320 , RAM  1330 , ROM  1340 , or secondary storage  1350  (which might include various disk-based systems such as hard disk, floppy disk, optical disk, or other drive such as the personality module  144  shown in  FIG. 2 ). While only one processor  1310  is shown, multiple processors may be present. Thus, while instructions may be discussed as being executed by a processor, the instructions may be executed simultaneously, serially, or otherwise by one or multiple processors. The processor  1310  may be implemented as one or more CPU chips. 
     The network connectivity devices  1320  may take the form of modems, modem banks, Ethernet devices, universal serial bus (USB) interface devices, serial interfaces, token ring devices, fiber distributed data interface (FDDI) devices, wireless local area network (WLAN) devices, radio transceiver devices such as code division multiple access (CDMA) devices, global system for mobile communications (GSM) radio transceiver devices, worldwide interoperability for microwave access (WiMAX) devices, and/or other well-known devices for connecting to networks. These network connectivity devices  1320  may enable the processor  1310  to communicate with the Internet or one or more telecommunications networks or other networks from which the processor  1310  might receive information or to which the processor  1310  might output information. 
     The network connectivity devices  1320  might also include one or more transceiver components  1325  capable of transmitting and/or receiving data wirelessly in the form of electromagnetic waves, such as radio frequency signals or microwave frequency signals. Alternatively, the data may propagate in or on the surface of electrical conductors, in coaxial cables, in waveguides, in optical media such as optical fiber, or in other media. The transceiver component  1325  might include separate receiving and transmitting units or a single transceiver. Information transmitted or received by the transceiver  1325  may include data that has been processed by the processor  1310  or instructions that are to be executed by processor  1310 . Such information may be received from and outputted to a network in the form, for example, of a computer data baseband signal or signal embodied in a carrier wave. The data may be ordered according to different sequences as may be desirable for either processing or generating the data or transmitting or receiving the data. The baseband signal, the signal embedded in the carrier wave, or other types of signals currently used or hereafter developed may be referred to as the transmission medium and may be generated according to several methods well known to one skilled in the art. 
     The RAM  1330  might be used to store volatile data and perhaps to store instructions that are executed by the processor  1310 . The ROM  1340  is a non-volatile memory device that typically has a smaller memory capacity than the memory capacity of the secondary storage  1350 . ROM  1340  might be used to store instructions and perhaps data that are read during execution of the instructions. Access to both RAM  1330  and ROM  1340  is typically faster than to secondary storage  1350 . The secondary storage  1350  is typically comprised of one or more disk drives or tape drives and might be used for non-volatile storage of data or as an over-flow data storage device if RAM  1330  is not large enough to hold all working data. Secondary storage  1350  may be used to store programs or instructions that are loaded into RAM  1330  when such programs are selected for execution or information is needed. 
     The I/O devices  1360  may include liquid crystal displays (LCDs), touch screen displays, keyboards, keypads, switches, dials, mice, track balls, voice recognizers, card readers, paper tape readers, printers, video monitors, transducers, sensors, or other well-known input or output devices. Also, the transceiver  1325  might be considered to be a component of the I/O devices  1360  instead of or in addition to being a component of the network connectivity devices  1320 . Some or all of the I/O devices  1360  may be substantially similar to various components depicted in the previously described  FIG. 1 , such as the temperature sensors  142  and  140 . 
     At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, Rl, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=Rl+k*(Ru−Rl), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention.