# Patent

## Title
Computational load distribution in a climate control system having plural sensing microsystems

## Abstract

Systems, methods, and related computer program products for controlling one or more HVAC systems using a distributed arrangement of wirelessly connected sensing microsystems are described. A plurality of wirelessly communicating sensing microsystems is provided, each sensing microsystem including a temperature sensor and a processor, at least one of the sensing microsystems being coupled to an HVAC unit for control thereof. The plurality of sensing microsystems is configured to jointly carry out at least one shared computational task associated with control of the HVAC unit. Each sensing microsystem includes a power management circuit configured to determine an amount of electrical power available for dedication to the at least one shared computational task. The at least one shared computational task is apportioned among respective ones of the plurality of sensing microsystems according to the amount of electrical power determined to be available for dedication thereto at each respective sensing microsystem.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Prov. Ser. No. 61/429,093 filed Dec. 31, 2010 and U.S. Prov. Ser. No. 61/415,771 filed Nov. 19, 2010, each of which is incorporated by reference herein. The subject matter of this provisional patent specification relates to the subject matter of the following commonly assigned applications: U.S. Ser. No. 12/881,430 filed Sep. 14, 2010; U.S. Ser. No. 12/881,463 filed Sep. 14, 2010; U.S. Ser. No. 12/987,257 filed Jan. 10, 2011; U.S. Ser. No. 13/034,666 filed Feb. 24, 2011; U.S. Ser. No. 13/034,674 filed Feb. 24, 2011; and U.S. Ser. No. 13/034,678 filed Feb. 24, 2011. Each of the above-referenced patent applications is incorporated by reference herein. The above-referenced patent applications are collectively referenced hereinbelow as “the commonly assigned incorporated applications.”


FIELD
This patent specification relates to system monitoring and control, such as to the monitoring and control of heating, cooling, and air conditioning (HVAC) systems. More particularly, this patent specification relates to systems, methods, and related computer program products for controlling one or more systems, such as HVAC systems, using a distributed arrangement of wirelessly connected sensing and control units.
BACKGROUND AND SUMMARY
Substantial effort and attention continues toward the development of newer and more sustainable energy supplies, the conservation of energy by increased energy efficiency remains crucial to the world's energy future. According to an October 2010 report from the U.S. Department of Energy, heating and cooling account for 56% of the energy use in a typical U.S. home, making it the largest energy expense for most homes. Along with improvements in the physical plant associated with home heating and cooling (e.g., improved insulation, higher efficiency furnaces), substantial increases in energy efficiency can be achieved by better control and regulation of home heating and cooling equipment. By activating heating, ventilation, and air conditioning (HVAC) equipment for judiciously selected time intervals and carefully chosen operating levels, substantial energy can be saved while at the same time keeping the living space suitably comfortable for its occupants.
For the purposes of controlling one or more HVAC systems for climate control in an enclosure, systems for that incorporate a distributed array of wirelessly communicating sensing units are known in art and discussed, for example, in U.S. Pat. No. 5,395,042, which is incorporated by reference herein. Different methods for powering the wirelessly communicating sensing units are also known in the art, including using standard building AC outlet power as discussed in US20080015740A1, standard battery-only power as discussed in US20070114295A1, and solar-charged battery power as discussed U.S. Pat. No. 5,395,042, supra. For wirelessly communicating thermostatic sensing units having control wires running directly to a conventional HVAC system, so-called “power stealing” or “parasitic powering” methods such as those discussed in U.S. Pat. No. 7,510,126 can be used, wherein a relatively small amount of power is extracted from a call relay coil voltage provided by the HVAC system. Each of the above-cited patents and patent publications is incorporated by reference herein.
For the purposes of controlling one or more HVAC systems for climate control in an enclosure, various computational methods have been proposed for optimizing the control of one or more HVAC systems in a manner that accommodates a balance of human comfort and energy efficiency, the optimizing being based at least in part on current and historical environmental readings and inputs acquired at a distributed network of sensing nodes. Examples of such proposals are discussed in U.S. Pat. No. 7,847,681 B2 and US20100262298A1, each of which is incorporated by reference herein. Generally speaking, such computational methods can involve multidimensional feedback control system characterization or “learning” of a climate control environment having one or more HVAC systems and/or simultaneous optimization of plural multidimensional feedback control system performance metrics (such as a “total suffering” metric described in US20100262298A1, supra) based on learned or known multidimensional feedback control system parameters and constraints characteristic of the climate control environment. Such computational tasks, which are termed “characterization and/or optimization algorithms” hereinbelow for clarity of description and not by way of limitation, can be of relatively high computational complexity and therefore can represent a relatively high computational load.
Provided according to an embodiment is a climate control system comprising a plurality of wirelessly communicating sensing microsystems, each sensing microsystem including a temperature sensor and a processor, at least one of the sensing microsystems being coupled to an HVAC unit for control thereof. The plurality of sensing microsystems is configured to jointly carry out at least one shared computational task associated with the control of the HVAC unit. Each sensing microsystem includes a power management circuit configured to determine an amount of electrical power available for dedication to the at least one shared computational task. The at least one shared computational task is apportioned among respective ones of the plurality of sensing microsystems according to the amount of electrical power determined to be available for dedication thereto at each respective sensing microsystem.



BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1C illustrate external views of a sensing microsystem according to an embodiment;
FIG. 2A illustrates a building enclosure including plural sensing microsystems and an HVAC system according to an embodiment;
FIG. 2B illustrates a conceptual diagram of an HVAC system as wired to a sensing microsystem according to an embodiment;
FIGS. 3A-3C illustrate examples of building enclosures including plural sensing microsystems and one or more HVAC systems according to one or more embodiments;
FIG. 4 illustrates a sensing microsystem and a conceptual functional block diagram thereof according to an embodiment;
FIG. 5 illustrates shared computational load distribution in a climate control system having plural sensing microsystems according to an embodiment; and
FIG. 6 illustrates shared computational load distribution in a climate control system having plural sensing microsystems according to an embodiment.



DETAILED DESCRIPTION
One or more of the embodiments described herein is particularly advantageous for use with climate control systems having plural wirelessly communicating sensing microsystems, such as those described in one or more of the commonly assigned incorporated applications, supra. More particularly, one or more of the embodiments described herein is particularly advantageous in the practical implementation of an easy-to-install, easy-to-administer, flexible, and scalable network of smart, visually appealing, “lightweight” sensing and control nodes, referenced herein as sensing microsystems, that cooperate to govern the operation of one or more HVAC systems in a manner that promotes an optimal balance of human comfort and energy efficiency for an enclosure, such as a residential or business building enclosure. By “lightweight,” it is meant that that the sensing microsystems are relatively compact and low-powered devices, comparable in size to handheld devices such as smartphones, and consuming relatively low amounts of electrical power, such as 10 watts or less. Lightweight computing devices, as that term is used herein, can be contrasted with computing devices having relatively heavy power usage, such as desktop computers whose average energy usage is often in the hundred as watts, and such as laptop or notebook computers whose average energy usage is generally well over 10 watts, and rarely under 20 watts. It is to be appreciated that while the above numerical examples provide a fair characterization of a “lightweight” computing device by current technological standards, one skilled in the art would be readily aware that a lesser dividing line, such as 1 watt or less of average energy usage, may provide a fair characterization of what is meant by a lightweight computing device as more energy-efficient microprocessor technologies are hereinafter developed.
It is to be appreciated that while one or more embodiments is detailed herein for the context of a residential home, such as a single-family house, the scope of the present teachings is not so limited, the present teachings being likewise applicable, without limitation, to duplexes, townhomes, multi-unit apartment buildings, hotels, retail stores, office buildings, industrial buildings, and more generally any living space or work space having one or more HVAC systems. It is to be further appreciated that while the terms user, customer, installer, homeowner, occupant, guest, tenant, landlord, repair person, and the like may be used to refer to the person or persons who are interacting with the sensing microsystem or other device or user interface in the context of some particularly advantageous situations described herein, these references are by no means to be considered as limiting the scope of the present teachings with respect to the person or persons who are performing such actions.
FIGS. 1A-1C illustrate external views of a sensing microsystem 100 for which shared computational load distribution in a climate control system having plural such sensing microsystems according to one or more embodiments is particularly suitable. For some embodiments, the sensing microsystem 100 corresponds to one or more of the intelligent, wirelessly communicating thermostatic units (termed in Ser. No. 61/429,093, supra, as a versatile sensing and control unit or VSCU) described in one or more of the commonly assigned incorporated applications, supra. As facilitated by its lightweight character, sensing microsystem 100 preferably has a sleek, elegant appearance that does not detract from home decoration, and indeed can serve as a visually pleasing centerpiece for the immediate location in which it is installed. The sensing microsystem 100 comprises a main body 108 that is preferably circular with a diameter of about 8 cm, and that has a visually pleasing outer finish, such as a satin nickel or chrome finish. Separated from the main body 108 by a small peripheral gap 110 is a cap-like structure comprising a rotatable outer ring 106, a sensor ring 104, and a circular display monitor 102. The outer ring 106 preferably has an outer finish identical to that of the main body 108, while the sensor ring 104 and circular display monitor 102 have a common circular glass (or plastic) outer covering that is gently arced in an outward direction and that provides a sleek yet solid and durable-looking overall appearance. The sensor ring 104 contains any of a wide variety of sensors including, without limitation, infrared sensors, visible-light sensors, and acoustic sensors. Preferably, the glass (or plastic) that covers the sensor ring 104 is smoked or mirrored such that the sensors themselves are not visible to the user. An air venting functionality is preferably provided, such as by virtue of the peripheral gap 110, which allows the ambient air to be sensed by an internal temperature sensor and any other internal sensors.
As discussed elsewhere in the commonly assigned incorporated applications, supra, for one embodiment the sensing microsystem 100 is controlled by only two types of user input, the first being a rotation of the outer ring 106 (FIG. 1B), and the second being an inward push on the outer ring 106 (FIG. 1C) until an audible and/or tactile “click” occurs. By virtue of user rotation of the outer ring 106 and the inward pushing of the outer ring 106 responsive to intuitive and easy-to-read prompts on the circular display monitor 102, the sensing microsystem 100 is advantageously capable of receiving all necessary information from the user for basic setup and operation.
FIG. 2A illustrates a plurality of wirelessly communicating sensing microsystems according to an embodiment, including a primary sensing microsystem 100 and an auxiliary sensing microsystem 100′, as installed in a house 201 having an HVAC system 299 and a set of control wires 298 extending therefrom. The primary sensing microsystem 100 is connected to the HVAC system 299 by the control wires 298 for control thereof, while the auxiliary sensing microsystem 100′ is disposed in a cradle or docking station 205 and placed, for example, on a nightstand 288 located in a bedroom of the house 201. As used herein, the term “primary sensing microsystem” refers to one that is electrically connected to actuate an HVAC system in whole or in part, which would necessarily include the first sensing microsystem purchased for any home, while the term “auxiliary sensing microsystem” or “remote sensing microsystem” refers to one or more additional sensing microsystems not electrically connected to actuate an HVAC system in whole or in part.
The primary sensing microsystem 100 and auxiliary sensing microsystem 100′ are each configured to automatically recognize the presence of the other and to communicate with each other using a wireless communication protocol such as Wi-Fi, ZigBee, or Z-Wave, represented generically in FIG. 2A by the electromagnetic radiation signals R. The wireless communications among the multiple sensing microsystems can be achieved in a networked fashion using a home wireless router (not shown), on an ad hoc or peer-to-peer basis, various combinations thereof, or any other method that can be used to achieve wireless communication thereamong. In one example, the primary sensing microsystem 100 of FIG. 2A receives its electrical power by virtue of a power-stealing scheme, wherein a relatively small amount of power is extracted from a call relay coil voltage provided by the HVAC system. In one example, the auxiliary sensing microsystem 100′ of FIG. 2A is powered from a building AC outlet 286, more particularly, by AC adapter circuitry (not shown) located in the docking station 205 and/or by an external “power brick” AC adapter (not shown) connected between docking station 205 and the wall outlet 286. In another examples, the primary sensing microsystem 100 of FIG. 2A receives its power from a common (C) HVAC signal wire provided by the HVAC system 299 as one of the control wires 298, while the auxiliary sensing microsystem 100′ could be powered by standard alkaline or lithium batteries. As used herein, the term “continuous line power” refers to power that is provided by a generally continuous, reliable source such that, for normal everyday operational purposes, it can be assumed that such power will be ongoing and not drained or otherwise time-limited. For purposes of the instant disclosure, examples of continuous line power includes power provided from standard 110-volt AC wall outlets, and power provided by the common (C) wire of an HVAC system. Notably, not all HVAC systems provide a common (C) wire, thereby giving rise to a need for the above-described power-stealing schemes for some primary sensing microsystem installations. For purposes of the present disclosure, power sources such as stand-alone lithium or alkaline batteries, power-stealing arrangements (with or without associated rechargeable batteries), and rooftop- or window-mounted solar power sources (with or without associated rechargeable batteries) would represent examples of power sources that are not continuous line power sources.
FIG. 2B illustrates an exemplary diagram of the HVAC system 299 of FIG. 2A. HVAC system 299 provides heating, cooling, ventilation, and/or air handling for an enclosure, such as the single-family home 201 depicted in FIG. 2A. The HVAC system 299 depicts a forced air type heating system, although according to other embodiments, other types of systems could be used. In heating, heating coils or elements 242 within air handler 240 provide a source of heat using electricity or gas via line 236. Cool air is drawn from the enclosure via return air duct 246 through filter 270 using fan 238 and is heated by the heating coils or elements 242. The heated air flows back into the enclosure at one or more locations through a supply air duct system 252 and supply air grills such as grill 250. In cooling, an outside compressor 230 passes a gas such as Freon through a set of heat exchanger coils to cool the gas. The gas then goes via line 232 to the cooling coils 234 in the air handlers 240 where it expands, cools and cools the air being circulated through the enclosure via fan 238. According to some embodiments a humidifier 262 is also provided which moistens the air using water provided by a water line 264. Although not shown in FIG. 2B, according to some embodiments the HVAC system for the enclosure has other known components such as dedicated outside vents to pass air to and from the outside, one or more dampers to control airflow within the duct systems, an emergency heating unit, and a dehumidifier. The HVAC system is selectively actuated via control electronics 212 that communicate with the primary sensing microsystem 100 over control wires 298.
FIGS. 3A-3C illustrate examples of building enclosures including plural sensing microsystems and one or more HVAC systems according to one or more embodiments, and are set forth to illustrate but a few examples of the wide variety of different combinations of primary sensing microsystems, auxiliary sensing microsystems, and HVAC systems that can used in conjunction with one or more of the preferred embodiments. Thus, for example, in FIG. 3A the house 201 contains a second HVAC system 399 that is wired to a second primary sensing microsystem 100′′ over a set of control wires 398, the second primary sensing microsystem 100′′ being powered by a power-stealing scheme with HVAC system 399. The primary sensing microsystems 100 and 100′′ communicate with each other and cooperate with each other to provide an overall optimal control of the household climate.
Illustrated in FIG. 3B is the configuration of FIG. 3A with the addition of the auxiliary sensing microsystem 100′ inserted into the docking station 205 that is powered by a building AC outlet. According to embodiments, an additional sensing microsystem, when docked or otherwise installed, will automatically detect and be detected by the existing sensing microsystems by wireless communication. The additional sensing microsystem will join in with the existing units to cooperate in unison for improved control heating and cooling control functionality. The additional information provided by virtue of the temperature sensing, occupancy sensing, etc. provided by the auxiliary sensing microsystem 100′ further enhances the quality of overall HVAC system control with respect to user comfort and/or energy efficiency.
Illustrated in FIG. 3C is the configuration of FIG. 3B with the addition of a second auxiliary sensing microsystem 100e, which is powered from a solar cell 301 and optionally includes an internal battery that is recharged by the solar cell 301. The external temperature (and optionally other sensed data such as outdoor humidity, motion sensing, etc.) sensed by the auxiliary sensing microsystem 100e can be advantageously used to even further enhance the quality of overall HVAC system control with respect to user comfort and/or energy efficiency. Although not required, the sensing microsystem 100e can be made simpler than the sensing microsystems 100, 100′, and 100′′ in that the user interface features can be omitted.
A variety of different docking station types and capabilities, and related interchangeabilities of primary and auxiliary sensing microsystems, are within the scope of the present teachings. For example, in one embodiment there is provided an HVAC-coupled docking station (not shown) that provides the required wiring connectivity to the HVAC unit and that optionally includes power-stealing circuitry. The various docking stations and sensing microsystems can be otherwise configured such that the different sensing microsystems can be interchanged into different docking stations, including an ability for a primary sensing microsystem to be placed into a nightstand docking station (thereby becoming an auxiliary sensing microsystem) and an ability for an auxiliary sensing microsystem to be placed into an HVAC-coupled docking station (thereby becoming a primary sensing microsystem).
For one embodiment, all sensing microsystems sold by the manufacturer can be identical in their core functionality, each being able to serve as either a primary sensing microsystem or auxiliary sensing microsystem as the case requires, although the different sensing microsystems may have different colors, ornamental designs, memory capacities, and so forth. For this embodiment, the user is advantageously able, if they desire, to interchange the positions of their sensing microsystems by simple removal of each one from its existing docking station and placement into a different docking station. Among other advantages, there is an environmentally, technically, and commercially appealing ability for the customer to upgrade to the newest, latest sensing microsystem designs and technologies without the need to throw away the existing sensing microsystem. For example, a customer with a single sensing microsystem (which is necessarily serving as a primary sensing microsystem) may be getting tired of its color or its TFT display, and may be attracted to a newly released sensing microsystem with a different color and a sleek new OLED display. For this case, in addition to buying the newly released sensing microsystem, the customer can buy a tabletop docking station to put on their nightstand. The customer can then insert their new sensing microsystem into the existing HVAC-coupled wall docking station, and then take their old sensing microsystem and insert it into the tabletop docking station. Advantageously, in addition to avoiding the wastefulness of discarding the old sensing microsystem, there is now a new auxiliary sensing microsystem at the bedside that not only provides increased comfort and convenience, but that also promotes increased energy efficiency by virtue of the additional multi-sensor information and processing power provided. For another embodiments, there can be a first class of sensing microsystems and associated docking stations that are specialized for use as primary sensing microsystems and interchangeable with each other, but not with a second class of sensing microsystems and associated docking stations that are specialized for use as auxiliary sensing microsystems, and which in turn are interchangeable with each other.
According to embodiments and as described in one or more of the commonly assigned incorporated applications, supra, a rich variety of capabilities is provided when one or more HVAC systems are controlled by one or more of the described sensing microsystems, with particularly advantageous operation being provided when plural sensing microsystems are used as in FIG. 2A and FIGS. 3A-3C. Although a particularly rich variety of capabilities is provided when the network of sensing microsystems is connected to the Internet, there is also a rich variety of capabilities provided even when there is no connection to the Internet. For scenarios in which there is no internet connectivity, the network of sensing microsystems is capable of performing tasks including, but not limited to: operating the one or more HVAC systems according to one or more heating/cooling schedules (template schedules) and sensed occupancies; providing a friendly user interface for easy modification of the template schedules and learning about user preferences and habits by question-and-answer; providing feedback on the user display regarding energy usage and usage patterns; “learning” about the preferences, habits, and occupancy patterns of the building occupants by virtue of sensor detection patterns, patterns of thermostatic control inputs, etc.; adapting to the learned preferences, habits, and occupancy patterns by static and/or dynamic modification to the template schedules; empirically modeling or otherwise characterizing the capabilities of the one or more HVAC systems and the thermal characteristics of the enclosure based on control inputs to the HVAC system(s) and distributed sensor data (as further facilitated by the outside weather sensing as facilitated by the externally positioned sensing microsystem 100e of FIG. 3C); and optimizing empirically and/or by system simulation the control of the one or more HVAC systems based on the determined thermal characteristics of the enclosure and/or the learned occupant preferences, habits, and occupancy patterns.
Further layers of advantageous functionality are provided for scenarios in which the sensing microsystems indeed have access to the Internet, the network of sensing microsystems being capable of performing tasks including, but not limited to: providing real time or aggregated home energy performance data to a utility company, a sensing microsystem data service provider, sensing microsystems in other homes, or other data destinations; receiving real time or aggregated home energy performance data from a utility company, sensing microsystem service provider, sensing microsystems in other homes, or other data sources; receiving new energy control algorithms or other software/firmware upgrades from one or more sensing microsystem service providers or other sources; receiving current and forecasted weather information for inclusion in energy-saving control algorithm processing; receiving user control commands from the user's computer, network-connected television, smart phone, or other stationary or portable data communication appliance (hereinafter collectively referenced as the user's “digital appliance”); providing an interactive user interface to the user through their digital appliance; receiving control commands and information from an external energy management advisor, such as a subscription-based service aimed at leveraging collected information from multiple sources to generate the best possible energy-saving control commands or profiles for their subscribers; receiving control commands and information from an external energy management authority, such as a utility company to whom limited authority has been voluntarily given to control the sensing microsystem in exchange for rebates or other cost incentives (e.g., for energy emergencies, “spare the air” days, etc.); providing alarms, alerts, or other information to the user on their digital appliance (and/or a user designee such as a home repair service) based on sensed HVAC-related events (e.g., the house is not heating up or cooling down as expected); providing alarms, alerts, or other information to the user on their digital appliance (and/or a user designee such as a home security service or the local police department) based on sensed non-HVAC related events (e.g., an intruder alert as sensed by the sensing microsystem's multi-sensor technology); and a variety of other useful functions enabled by network connectivity.
In view of the rich variety of capabilities provided by the network of sensing microsystems as described above, it has been found that a significant tension can arise between providing a network of easy-to-install, easy-to-administer, flexible, “lightweight” sensing microsystems, while at the same time providing advanced climate governance functionality that can require significant computing power. Thus, for example, according to one experiment reported in U.S. Pat. No. 7,510,126, supra, a “parasitic” or “power-stealing” circuit should draw no more than 55 milliwatts in order for most typical HVAC systems to remain unaffected. With reference to FIGS. 3A-3C, this can substantially limit the amount of computational load that can be carried out by the primary sensing microsystems 100 and 100′′ for installations in which they are powered by parasitic or power-stealing methods. Likewise, there may be substantial limits on the amount of incoming or battery-stored solar power available to the sensing microsystem 100e depending on the time of day, how sunny the weather is, and other factors. Notably, even for the auxiliary sensing microsystem 100′ that derives its power from the AC wall outlet, that power level is not necessarily unlimited, but rather is limited by aesthetic design concerns, expense concerns, and heating concerns, including concerns about keeping the weight and bulkiness of “power brick” circuitry within tolerable levels at reasonable costs, and including concerns that relate to heat dissipation by the microprocessor circuitry.
FIG. 4 illustrates a sensing microsystem 100 and a conceptual functional block diagram thereof according to an embodiment. The sensing microsystem 100 of FIG. 4 can represent, without limitation, either a primary or auxiliary sensing microsystem. Sensing microsystem 100 comprises a core operations module 402, a power management and detection availability module 404, a cooperative load balancing module 406, and a shared computing module 408. The modules 402-408 may be implemented using any of a variety of different architectures without departing from the scope of the present teachings, ranging from a first example in which they are provided as separate electronic components in electrical and data communication with each other, to a second example in which they are provided as separate or integrated software routines for execution by a common microprocessor, and including any combination thereof.
The sensing microsystem 100 comprises physical hardware and firmware configurations, along with hardware, firmware, and software programming that is capable of carrying out the currently described methods. In view of the instant disclosure, a person skilled in the art would be able to realize the physical hardware and firmware configurations and the hardware, firmware, and software programming that embody the physical and functional features described herein without undue experimentation using publicly available hardware and firmware components and known programming tools and development platforms. By way of example, power sensing circuitry capable of determining an available amount of discretionary power, either on an instantaneous power availability basis (e.g., milliwatts) or an interval-based power availability basis (e.g., milliwatt-hours) based on incoming external power and/or stored power levels are known and commonly used in smartphone and other portable device technology. By way of further example, automated methods for computational load balancing, including both static methods (i.e., the shared computational task is distributed once among the different processing nodes and carried through to completion at each node) and dynamic methods (i.e., the shared computational task is re-distributed at selected intervals according to changing conditions) are known in the art and discussed generally, for example, in Bourke, Server Load Balancing, O'Reilly & Associates (2001), and White, et. al., “A Conceptual Model for Simulation Load Balancing,” Proc. 1998 Spring Simulation Interoperability Workshop (1998), each of which is incorporated by reference herein.
According to an embodiment, core operations module 402 is configured to carry out the more basic tasks of the sensing microsystem 100 that would not generally be considered as candidates for load sharing, with examples including temperature sensing, occupancy sensing, providing a user interface for any walk-up users, and wireless data communications tasks that communicate associated basic information. For operation as a primary sensing microsystem, the core operations module 402 would further carry out comparisons of sensed temperatures to template schedules and sending appropriate actuation signals to the HVAC system to which it is coupled. In contrast, shared computing module 408 is configured to carry out the more advanced computational tasks whose promptness of execution would be substantially enhanced by load sharing among multiple nodes, such as the complex characterization and/or optimization algorithms discussed above.
System simulation algorithms represent one particular set of computational tasks that can benefit from load sharing. An example of an advantageous use of system simulation in a climate control environment would be to run a series of “what if” or “test cases” based on a model of the enclosure environment, which can be heavily recursive and therefore computationally intensive tasks which are relatively difficult for a single “lightweight” processor to achieve in a reasonable period of time. A variety of complex computations may also benefit from load sharing, including machine learning and mathematical optimization algorithms relating to system characterization, home occupancy prediction, set point optimization, and other computational goals, which can be carried out using one or more known technologies, models, and/or mathematical strategies including, but not limited to, artificial neural networks, Bayesian networks, genetic programming, inductive logic programming, support vector machines, decision tree learning, clustering analysis, dynamic programming, stochastic optimization, linear regression, quadratic regression, binomial regression, logistic regression, simulated annealing, and other learning, forecasting, and optimization techniques.
According to an embodiment, power management and availability detection module 404 is configured to determine an amount of electrical power available for dedication to the shared computational task that is carried out by shared computing module 408. For one embodiment, power management and availability detection module 404 is configured to (a) determine a total amount of electrical power available to the sensing microsystem 100, (b) determine the amount of electrical power required for the core operations of the sensing microsystem, those core operations including at least one temperature sensing task and at least one wireless communication task, and (c) determining the amount of electrical power that can be dedicated to the shared computing task (i.e., expended by shared computing module 408) based on the difference between the total available power and the required core operations power. For purposes of clarity of description and not by way of limitation, the amount of electrical power determined to be available for dedication to the shared computing task is referenced herein as “spare” electrical power.
According to an embodiment, cooperative load balancing module 406 is configured to cooperate with the other sensing microsystems to allocate the shared computational task thereamong according to the amount of “spare” power available at each of them, that is, the amount of power that is available to be dedicated to the shared computing task as determined by the power management and availability detection module 404. A variety of different strategies and relational architectures can be used for load balancing among the different sensing microsystems without departing from the scope of the present teachings. In one example, the load allocation decisions can be dictated solely by one of the primary sensing microsystems, such as the primary sensing microsystem connected to the HVAC unit in a single-HVAC system installation, based on information reported to it by the auxiliary sensing microsystems. To achieve this with a common code base applied across all of the sensing microsystems, each is programmed with a basic self-awareness module in which it is determined whether that module is a primary sensing microsystem or an auxiliary sensing microsystem. Software switches can then be programmed in such that a different load balancing module 406 is actuated depending on whether that unit is a primary or auxiliary sensing microsystem. The load balancing module 406 for the primary sensing microsystem would contain the “master” load-balancing routine that allocates the load, while the load balancing modules 406 for the auxiliary sensing microsystem would contain the “servant” modules that carry out the decisions of the “master” routine. However, a variety of other strategies and relational architectures, including more democratic methods of load balancing decision making, are also within the scope of the present teachings.
For one embodiment, the power management and availability detection module 404 is configured to (a) estimate a maximum marginal power beyond the required core operations power that can be consumed by the sensing microsystem without introducing unacceptable error into thermal readings acquired by its temperature sensor, and (b) limit the determined amount of electrical power available to shared computing module 408 to that maximum marginal power if it is less than the difference between the total available power and the required core operations power.
Any of a variety of different measurements, metrics, estimations, or expressions can be used to characterize power availability without departing from the scope of the present teachings. For one embodiment, the determined amount of “spare” electrical power available is expressed as an analog value in physical units representative of an electrical power and/or electrical energy level. For another embodiment, determined amount of “spare” electrical power available is expressed as a logical value representative of one of a predetermined plurality of categories generally characteristic of an electrical power availability. By way of example, in one embodiment the amount of “spare” electrical power can be a simple binary YES or NO, or AVAILABLE or NOT AVAILABLE. In other embodiments the amount can be expressed on a three-way logical scale, such as HIGH AVAILABILITY, LIMITED AVAILABILITY, and NO AVAILABILITY. In still other embodiments the amount of “spare” power can be expressed on an N-way logical scale, e.g., a digit between 0 and N−1 where 0 represents no availability and N−1 represents a maximum availability.
FIG. 5 illustrates shared computational load distribution in a climate control system having plural sensing microsystems, such as the sensing microsystem 100 of FIG. 4, according to an embodiment. At step 502, at each sensing microsystem, an amount of electrical power available for dedication to the shared computational task is determined. At step 504, each sensing microsystem cooperates with all other sensing microsystems to allocate thereamong respective portions of the shared computational task according to the amount of electrical power determined to be available for dedication thereto at each respective sensing microsystem. At step 506, each sensing microsystem carries out its respective portion of the shared computational task.
For one embodiment, the shared computational task is apportioned such that each of the sensing microsystems having a greater amount of “spare” electrical power is assigned a heavier associated computational load than each of the sensing microsystems having a lesser amount of “spare” electrical power available. For another embodiment, the overall computational load is allocated to each sensing microsystem in percentagewise proportion to the percentage of the overall amount of “spare” electrical power available thereat. For example, if there are two sensing microsystems including a first sensing microsystem having 75% of the overall available “spare” electrical power and a second sensing microsystem having 25%, then the shared computational load is split 75/25 between those sensing microsystems.
For other embodiments in which spare power availability is expressed as a logical value, such as YES or NO, the computational load distribution can be based on an even division among the YES sensing microsystems. For example, if there are three sensing microsystems including a first sensing microsystem having a “spare” electrical power of NO, and second and third sensing microsystems each having a “spare” electrical power of YES, then the shared computational load can be split 50/50 between the second and third sensing microsystems.
FIG. 6 illustrates shared computational load distribution in a climate control system having plural sensing microsystems according to an embodiment. At step 602, it is determined whether any of the sensing microsystems are connected to continuous line power (such as the sensing microsystem 100′ of FIG. 3B), and if so, then the allocation of the shared computational load is weighted toward those sensing microsystems at step 606. In one example, all or substantially all of the shared computational load is allocated to the sensing microsystem(s) that are connected to continuous line power. If none of the sensing microsystems are connected to continuous line power, then step 604 is carried out in which the shared computational load is allocated pro rata to each sensing microsystem in percentagewise proportion to its share of the overall amount of “spare” electrical power available.
Thus provided according to one or more embodiments is an ability for the multiple sensing microsystems to judiciously share computing tasks among them in an optimal manner based on power availability and/or circuitry heating criteria. Many of the advanced sensing, prediction, and control algorithms provided with the sensing microsystems are relatively complex and computationally intensive, and can result in high power usage and/or device heating if carried out unthrottled. For one embodiment, the intensive computations are automatically distributed such that a majority (or plurality) of them are carried out on a subset of the sensing microsystems known to have the best power source(s) available at that time, and/or to have known to have the highest amount of stored battery power available. Thus, for example, because it is generally preferable for each primary sensing microsystem not to require household AC power for simplicity of installation as well as for equipment safety concerns, primary sensing microsystems will often be powered by energy harvesting from one or more of the 24 VAC call relay power signals if there is no common (C) wire provided by the HVAC system, and therefore may only have a limited amount of extra power available for carrying out intensive computations. In contrast, a typical auxiliary sensing microsystem may be a nightstand unit (e.g. docking station 205 in FIG. 2A, supra) that can be plugged in as easily as a clock radio. In such cases, much of the computational load can be assigned to the auxiliary sensing microsystem so that power is preserved in the primary sensing microsystem. In another embodiment, the speed of the intensive data computations carried out by the auxiliary sensing microsystem (or, more generally, any sensing microsystem unit to which the heavier computing load is assigned) can be automatically throttled using known techniques to avoid excessive device heating, such that temperature sensing errors in that unit are avoided. In yet another embodiment, the temperature sensing functionality of the sensing microsystem to which the heavier computing load is assigned can be temporarily suspended for an interval that includes the duration of the computing time, such that no erroneous control decisions are made if substantial circuitry heating does occur.
Whereas many alterations and modifications of the present invention will no doubt become apparent to a person of ordinary skill in the art after having read the foregoing description, it is to be understood that the particular embodiments shown and described by way of illustration are in no way intended to be considered limiting. By way of example, although the each of the distributed microsystems in one or more embodiments described above includes a temperature sensor, in other embodiments one or more of the distributed microsystems may omit a temperature sensor while having one or more other types of sensors (e.g., humidity only, occupancy detector only) that are useful in achieving optimal climate control, and/or that are useful in achieving a particular type of climate control.
By way of further example, according to another embodiment there is provided a method in which it is determined whether data communications can be established, or have been established, between one or more of the plurality of lightweight sensing microsystems and an external “heavyweight” node, such as a laptop computer, desktop computer, or other network-attached computing device that does not have a climate sensor or is otherwise normally dedicated to a purpose unrelated to climate control of that enclosure, and that has a relatively high computing capacity and an at least temporary availability to assist in the shared computational load. If such heavyweight node is available, some or all of the shared computational load is offloaded to that external heavyweight node by preparation of a self-contained package of executable code and source data, and transmission of the self-contained package to the external heavyweight node.
By way of further example, it is to be appreciated that the time intervals for which any particular shared computing task allocation is effective can range from relatively long intervals (e.g., where the task assignments are rebalanced once every several minutes to once every several hours based on changed conditions), to very short intervals (e.g., where the task assignments are rebalanced once every few seconds or less based on changed conditions) without departing from the scope of the embodiments. Likewise, the time intervals for rebalancing can be interrupted for various reasons without departing from the scope of the embodiments. Thus, for example, if the network of sensing microsystems is sharing a large simulation load equally, but then a user walks up to one of the sensing microsystems and begins interacting with that unit, the determined amount of “spare” power for that sensing microsystem can be instantly set to zero and the load rebalanced over the other available sensing microsystems. As another example, if the network of sensing microsystems is sharing a large simulation load, but then a user walks up to one of the sensing microsystems and begins interacting with that unit, the determined amount of “spare” power for all sensing microsystem can be instantly set to zero, thus effectively suspending the shared computational task, until the user has walked away, whereupon the shared computational task can be resumed.
By way of even further example, while computational load balancing among a plurality of smart, lightweight (e.g., low power) sensing microsystems according to respective spare power availability at those sensing microsystems has been found to be particularly advantageous for use in achieving practical, appealing, flexible, scalable, and efficient control of one or more HVAC systems in a climate control system according to one or more of the above-described embodiments, it is to be appreciated that the scope of the present teachings is not so limited. Rather, computational load balancing among a plurality of smart, lightweight (e.g., low power) sensing microsystems for control of one or more HVAC systems in a climate control system can be based on any of a variety of other criteria, either as adjunct criteria together with the spare power availability criterion, or as alternative stand-alone criteria, without departing from the scope of the present teachings. Such other criteria upon which the computational load balancing can be based on factors including, but not limited to: the type of microprocessor included in each sensing microsystem; the type of sensor included in each sensing microsystem; the location at which each sensing microsystem is installed within or outside the enclosure; the amount and type of core functionalities for which each respective sensing microsystem is responsible; and the amount and type of immediate non-shared-task related inputs and/or outputs being processed and/or provided by that sensing microsystem at a physical user interface thereof and/or by wireless communication therewith. Therefore, reference to the details of the embodiments are not intended to limit their scope.
Embodiments also include a non-transitory computer readable medium tangibly embodying one or more sequences of instructions wherein execution of the one or more sequences of instructions by a plurality of processors contained in a respective plurality of wirelessly communicating sensing microsystems of a distributed climate control system causes the plurality of sensing microsystems to: cooperatively control an HVAC unit based at least in part on temperature readings acquired by a plurality of temperature sensors located respectively in said plurality of sensing microsystems; and carry out at least one shared computational task associated with said cooperative control of the HVAC unit, comprising: at each sensing microsystem, determining an amount of electrical power available for dedication to the at least one shared computational task; and allocating among the sensing microsystems respective portions of the least one shared computational task according to the amount of electrical power determined to be available for dedication thereto at each respective sensing microsystem.

## Claims

1. A climate control system, comprising:
a plurality of wirelessly communicating sensing microsystems, each said sensing microsystem including a temperature sensor and a processor, at least one of said sensing microsystems being coupled to an HVAC unit for control thereof, said plurality of sensing microsystems being configured to jointly carry out at least one shared computational task associated with the control of the HVAC unit; and
for each said sensing microsystem, a power management circuit configured to determine an amount of electrical power available for dedication to said at least one shared computational task;
wherein said at least one shared computational task is apportioned among respective ones of said plurality of sensing microsystems according to the amount of electrical power determined to be available for dedication thereto at each said respective sensing microsystem.

2. The climate control system of claim 1, wherein said at least one shared computational task is apportioned such that each of said sensing microsystems having a greater amount of electrical power available for dedication to said at least one shared computational task is assigned a heavier associated computational load than each of said sensing microsystems having a lesser amount of electrical power available for dedication to said at least one shared computational task.

3. The climate control system of claim 2, wherein said at least one shared computational task being characterized by an overall computational load, said plurality of sensing microsystems having an overall amount of electrical power available for dedication to said at least one shared computational task, wherein each said sensing microsystem is assigned to carry out a percentage of said overall computation load that is proportional to a percentage of said overall amount of electrical power determined to be available at that sensing microsystem.

4. The climate control system of claim 2, wherein said at least one shared computational task being characterized by an overall computational load, said plurality of sensing microsystems including a first sensing microsystem coupled to the HVAC unit and powered by a call relay power-stealing circuit, said plurality of sensing microsystems including a second sensing microsystem powered from a continuous line power source, wherein the at least one shared computational task is apportioned such that a majority of the overall computational load is assigned to said second sensing microsystem.

5. The climate control system of claim 4, wherein substantially all of said overall computational load is assigned to said second sensing microsystem.

6. The climate control system of claim 1 wherein, for each of said sensing microsystems, said determined amount of electrical power available for dedication to said at least one shared computational task is expressed as an analog value in physical units representative of an electrical power and/or electrical energy level.

7. The climate control system of claim 1, wherein, for each of said sensing microsystems, said determined amount of electrical power available for dedication is expressed as a logical value representative of one of a predetermined plurality of categories generally characteristic of an electrical power availability for dedication to said at least one shared computational task.

8. The climate control system of claim 7, wherein said predetermined plurality of categories is selected from the group consisting of: available/not available; high availability/low availability/no availability; and high availability/medium availability/low availability/not available.

9. The climate control system of claim 1, wherein said power management circuit of each said sensing microsystem is configured to determine said amount of electrical power available for dedication to said at least one shared computational task according to the steps of:
determining a total amount of electrical power available to the sensing microsystem;
determining an amount of electrical power required for a core functionality of the sensing microsystem that is distinct from said at least one shared computational task, said core functionality including at least one temperature sensing task and at least one wireless communication task; and
determining the amount of electrical power available for dedication to said at least one shared computational task based on a difference between said total available power and said required core functionality power.

10. The climate control system of claim 9, wherein said determining the amount of electrical power available for dedication further comprises:
estimating a maximum marginal power beyond said required core functionality power that can be consumed by said sensing microsystem without introducing unacceptable error into thermal readings acquired by said temperature sensor; and
limiting said determined amount of electrical power available for dedication to said maximum marginal power if said maximum marginal power is less than said difference between said total available power and said required core functionality power.

11. The climate control system of claim 1, wherein said at least one shared computational task is selected from the group consisting of: environmental system characterization based on historical control signals applied to the HVAC system and thermal responses thereto as measured by said temperature sensors; environmental system simulation; and computation of one or more optimal HVAC control strategies based on environmental system characterization and simulation.

12. A method of operation for a plurality of wirelessly communicating sensing microsystems of a distributed climate control system, each sensing microsystem including a temperature sensor and a processor, at least one of the sensing microsystems being coupled to an HVAC unit for control thereof, the plurality of sensing microsystems cooperating to control the HVAC unit based at least in part on temperature readings acquired by the plurality of temperature sensors, the plurality of sensing microsystems being configured to jointly carry out at least one shared computational task associated with the control of the HVAC unit, the method comprising:
at each sensing microsystem, determining an amount of electrical power available for dedication to the at least one shared computational task;
allocating among the sensing microsystems respective portions of the least one shared computational task according to the amount of electrical power determined to be available for dedication thereto at each respective sensing microsystem; and
at each sensing microsystem, carrying out the respective portion of the least one shared computational task allocated thereto.

13. The method of claim 12, wherein said at least one shared computational task is allocated such that each of said sensing microsystems having a greater amount of electrical power available for dedication to said at least one shared computational task is assigned a heavier associated computational load than each of said sensing microsystems having a lesser amount of electrical power available for dedication to said at least one shared computational task.

14. The method of claim 13, wherein said at least one shared computational task being characterized by an overall computational load, said plurality of sensing microsystems including a first sensing microsystem coupled to the HVAC unit and powered by a call relay power-stealing circuit, said plurality of sensing microsystems including a second sensing microsystem powered from a continuous line power source, wherein the at least one shared computational task is allocated such that a majority of the overall computational load is assigned to said second sensing microsystem.

15. The method of claim 12 wherein, for each of said sensing microsystems, said determined amount of electrical power available for dedication to said at least one shared computational task is expressed as an analog value in physical units representative of an electrical power and/or electrical energy level.

16. The method of claim 12, wherein, for each of said sensing microsystems, said determined amount of electrical power available for dedication is expressed as a logical value representative of one of a predetermined plurality of categories generally characteristic of an electrical power availability for dedication to said at least one shared computational task.

17. The method of claim 16, wherein said predetermined plurality of categories is selected from the group consisting of: available/not available; high availability/low availability/no availability; and high availability/medium availability/low availability/not available.

18. A non-transitory computer readable medium tangibly embodying one or more sequences of instructions wherein execution of the one or more sequences of instructions by a plurality of processors contained in a respective plurality of wirelessly communicating sensing microsystems of a distributed climate control system causes the plurality of sensing microsystems to:
cooperatively control an HVAC unit based at least in part on temperature readings acquired by a plurality of temperature sensors located respectively in said plurality of sensing microsystems; and
carry out at least one shared computational task associated with said cooperative control of the HVAC unit, comprising:
at each sensing microsystem, determining an amount of electrical power available for dedication to the at least one shared computational task; and
allocating among the sensing microsystems respective portions of the least one shared computational task according to the amount of electrical power determined to be available for dedication thereto at each respective sensing microsystem.

19. The computer readable medium of claim 18, wherein said at least one shared computational task is selected from the group consisting of: environmental system characterization based on historical control signals applied to the HVAC system and thermal responses thereto as measured by said temperature sensors; environmental system simulation; and computation of one or more optimal HVAC control strategies based on environmental system characterization and simulation.

20. The computer readable medium of claim 18, wherein said at least one shared computational task is allocated such that each of said sensing microsystems having a greater amount of electrical power available for dedication to said at least one shared computational task is assigned a heavier associated computational load than each of said sensing microsystems having a lesser amount of electrical power available for dedication to said at least one shared computational task.

21. The computer readable medium of claim 20, wherein said at least one shared computational task being characterized by an overall computational load, said plurality of sensing microsystems including a first sensing microsystem coupled to the HVAC unit and powered by a call relay power-stealing circuit, said plurality of sensing microsystems including a second sensing microsystem powered from a continuous line power source, wherein the at least one shared computational task is allocated such that a majority of the overall computational load is assigned to said second sensing microsystem.

22. The computer readable medium of claim 18 wherein, for each of said sensing microsystems, said determined amount of electrical power available for dedication to said at least one shared computational task is expressed as an analog value in physical units representative of an electrical power and/or electrical energy level.

23. The computer readable medium of claim 18, wherein, for each of said sensing microsystems, said determined amount of electrical power available for dedication is expressed as a logical value representative of one of a predetermined plurality of categories generally characteristic of an electrical power availability for dedication to said at least one shared computational task.

24. The computer readable medium of claim 23, wherein said predetermined plurality of categories is selected from the group consisting of: available/not available; high availability/low availability/no availability; and high availability/medium availability/low availability/not available.