Abstract: A user-friendly programmable thermostat is described that includes a central electronic display surrounded by a ring that can be rotated and pressed inwardly to provide user input in a simple and elegant fashion. The current temperature and setpoint are graphically displayed as prominent tick marks. Different colors and intensities can be displayed to indicate currently active HVAC functions and an amount of heating or cooling required to reach a target temperature. The setpoint can be altered by user rotation of the ring. The schedule can be displayed and altered by virtue of rotations and inward pressings of the ring. Initial device set up and installation, the viewing of device operation, the editing of various settings, and the viewing of historical energy usage information are made simple and elegant by virtue of the described form factor, display modalities, and user input modalities of the device.

Abstract: An electronic thermostat and associated methods are disclosed for power stealing from an HVAC triggering circuit. The methods include making voltage measurements while controlling the amount of current drawn by the power stealing circuitry so as to determine a relationship that can be used to select how much current to draw during power stealing. Through the use of the described methods, the likelihood of inadvertent switching of the HVAC function (on or off) can be significantly reduced.

Abstract: Methods for controlling temperature in a conditioned enclosure such as a dwelling are described that include an “auto-away” and/or “auto-arrival” feature for detecting unexpected absences which provide opportunities for significant energy savings through automatic adjustment of the setpoint temperature. According to some preferred embodiments, when no occupancy has been detected for a minimum time interval, an “auto-away” feature triggers a changes of the state of the enclosure, and the actual operating setpoint temperature is changed to a predetermined energy-saving away-state temperature, regardless of the setpoint temperature indicated by the normal thermostat schedule. The purpose of the “auto away” feature is to avoid unnecessary heating or cooling when there are no occupants present to actually experience or enjoy the comfort settings of the schedule, thereby saving energy.

Abstract: In a multi-sensing, wirelessly communicating learning thermostat that uses power-harvesting to charge an internal battery, methods are disclosed for ensuring that the battery does not become depleted or damaged while at the same time ensuring selected levels of thermostat functionality. Battery charge status is monitored to determine whether the present rate of power usage needs to be stemmed. If the present rate of power usage needs to be stemmed, then a progression of performance levels and/or functionalities are scaled back according to a predetermined progressive power conservation algorithm. In a less preferred embodiment, there is a simple progressive shutdown of functionalities turned off in sequence until the desired amount of discharge stemming is reached. Battery charge preservation measures are also described for cases when an interruption of external supply power used to recharge the battery is detected.

Abstract: A device for determining a density of a fluid including a mechanical resonator, a driver/receiver unit arranged to provide an actuation to the mechanical resonator, sense a response of the mechanical resonator to the actuation, and provide an output signal representing the response; and an evaluation unit. The evaluation unit of the device is arranged to determine an oscillation distribution from the output signal, determine a resonance frequency estimate from the oscillation distribution, and determine the density of the fluid based upon the resonance frequency estimate. The device enables a more accurate determination of the fluid density for fluids including immiscible components (thus forming a heterogeneous mixture), like a water-oil emulsion, or a fluid with occluded gas.

Abstract: A thermostat for controlling an HVAC system is described, the thermostat having a user interface that is visually pleasing, approachable, and easy to use while also providing ready access to, and intuitive navigation within, a menuing system capable of receiving a variety of different types of user settings and/or control parameters. For some embodiments, the thermostat comprises a housing, a ring-shaped user-interface component configured to track a rotational input motion of a user, a processing system configured to identify a setpoint temperature value based on the tracked rotational input motion, and an electronic display coupled to the processing system. An interactive thermostat menuing system is accessible to the user by an inward pressing of the ring-shaped user interface component. User navigation within the interactive thermostat menuing system is achievable by virtue of respective rotational input motions and inward pressings of the ring-shaped user interface component.

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.

Abstract: A user-friendly programmable thermostat is described that includes a circular body having a large central display surrounded by a ring that can be rotated an pressed inward by a user so as to receive user input in a simple elegant fashion. Different colors can be displayed to the user to indicate currently active HVAC functions, and different shades of colors can be displayed to a user to indicate an estimated amount of time and/or energy for reaching a target temperature. The thermostat is wall mountable and is made up of a head unit removeably mounted to a backplate. A locking mechanism can be provided so as to increase security against unauthorized removal of the head unit. The backplate can be adapted to be mounted on a wall so as to be level, for example by including a bubble level on the backplate. One or more vents are preferably located on the sides of the body, such as in a gap beneath the translatably mounted ring, and/or in a gap between the head unit and the backplate.

Abstract: A thermostat for controlling an HVAC system is described, the thermostat having a user interface that is visually pleasing, approachable, and easy to use while also providing intuitive navigation within a menuing system. In a first mode of operation, an electronic display of the thermostat displays a population of tick marks arranged in an arcuate arrangement including a plurality of background tick marks, a setpoint tick mark representing a setpoint temperature, and an ambient temperature tick mark representing an ambient temperature, the setpoint temperature being dynamically changeable according to a tracked rotational input motion of a ring-shaped user interface component of the thermostat. In a second mode, the a plurality of user-selectable menu options is displayed in an arcuate arrangement along a menu option range area, and respective ones of the user-selectable menu options are selectively highlighted according to the tracked rotational input motion of the ring-shaped user interface component.

Abstract: A thermostat for controlling an HVAC system and related systems, methods, and computer program products for facilitating user-friendly installation of the thermostat are described. For one embodiment, automated installation verification is performed by the thermostat by automatically sensing which wires have been inserted, selecting a candidate HVAC operating function (e.g., heating or cooling) that is consistent with a subset of HVAC signal types indicated by the inserted wires, applying control signals to the HVAC system to invoke that HVAC operating function, and processing a time sequence of acquired temperature readings to determine whether that HVAC operating function was successfully carried out. For one embodiment, the initial automated testing of the heating and cooling functions are only carried out at times for which such heating or cooling function would normally be invoked during normal operation of the thermostat. Automated determination of a heat pump call convention is also described.

Abstract: A thermostat and related methods is provided for controlling an HVAC system. The thermostat includes wiring terminals adapted and configured to make an electrical connection with an HVAC system wires such as common, heating and cooling control and return wires. The making of the connection with a common wire actuates switching open a loop of an electrical circuit used for power harvesting. According to some embodiments, the wiring terminal includes actuation of a moveable part of the terminal so as to accommodate the common wire that in turn actuates the switching open the power harvesting loop. More than one other loop can be switched. According to some embodiments, the wiring terminal can be used to automatically connect and/or disconnect Rc and Rh circuits when one or both Rc and Rh wires are present. According to some embodiments, the wiring terminal can be used for electronically sensing the presence of the HVAC system wire.

Abstract: A thermostat and related methods is provided for controlling an HVAC system having one or two separate transformers for supplying power to the HVAC system. The thermostat includes isolation circuitry housed within the thermostat to safely connect to the HVAC control wires and power wire(s) whether the HVAC system has one or two separate transformers without the use of removable jumpers or manual rewiring. The thermostat can include a processor that sends DC signals for turning on and turning off each of the HVAC functions, and an isolator adapted to electrically isolate the processor from the control wires and power wire(s). The isolator can include a transformer, such as a low cost Ethernet transformer. The circuitry can include one or more field effect transistors adapted and arranged so as to open or close an electrical connections between the control and power wires, thereby turning on or off the associated HVAC function.

Abstract: A thermostat for controlling an HVAC system is described, the thermostat having a user interface that is visually pleasing, approachable, and easy to use while also providing ready access to, and intuitive navigation within, a menuing system capable of receiving a variety of different types of user settings and/or control parameters. For some embodiments, the thermostat comprises a housing, a ring-shaped user-interface component configured to track a rotational input motion of a user, a processing system configured to identify a setpoint temperature value based on the tracked rotational input motion, and an electronic display coupled to the processing system. An interactive thermostat menuing system is accessible to the user by an inward pressing of the ring-shaped user interface component. User navigation within the interactive thermostat menuing system is achievable by virtue of respective rotational input motions and inward pressings of the ring-shaped user interface component.

Abstract: A method is described for identifying faults relating to an HVAC system, such a clogged filter. Sensor data is used to estimate HVAC system efficiency. Trends in system efficiency are then used to identify faults such as clogged filters. The sensor(s) can include one or more of the following types: optical sensor, temperature sensor, pressure sensor, acoustic transducer, humidity sensor, resistive sensor, capacitive sensor, and infrared sensor. The efficiency estimation can also be based on conditions external to the building, such as data from exterior sensors and/or data gathered from third parties such as government or private weather stations. The efficiency estimation can also be based on performance metrics such as the time used to reach a set point temperature. The fault identification includes filtering out non-fault related events. An instrumented air filter for use with an HVAC system is also described.

Abstract: A thermostat is described for controlling air temperature in a building. The time associated with causing the controlled air temperature to reach a target temperature is estimated and displayed to a user. Input from a user indicating the target temperature can be received and the estimating and displaying can be carried out in real time. The thermostat can be wall-mounted or the user input can be received and estimated time can be displayed using a remote device, for example that communicates wirelessly with other components of the HVAC system.

Abstract: A thermostat and related methods are described for controlling one or more functions, such as heating and cooling in an HVAC. According to some embodiments the thermostat includes a rechargeable battery; charging circuitry adapted and arranged to recharge the battery; and control circuitry adapted and arranged to control the one or more HVAC functions using power from the rechargeable battery. According to some embodiments, the thermostat also includes power harvesting circuitry adapted and arranged to harvest power from the HVAC system in cases where no common wire is available to the thermostat, and to supply power to the charging circuit for recharging the battery.

Abstract: Systems and methods are described for predicting and/or detecting occupancy of an enclosure, such as a dwelling or other building, which can be used for a number of applications. An a priori stochastic model of occupancy patterns based on information of the enclosure and/or the expected occupants of the enclosure is used to pre-seed an occupancy prediction engine. Along with data from an occupancy sensor, the occupancy prediction engine predicts future occupancy of the enclosure. Various systems and methods for detecting occupancy of an enclosure, such as a dwelling, are also described.

Abstract: Systems and methods for modeling the behavior of an enclosure for use by a control system of an HVAC system are described. A model for the enclosure that describes the behavior of the enclosure for use by the control system is updated based on a weather forecast data. The weather forecast data can include predictions more than 24 hours in the future, and can include predictions such as temperature, humidity and/or dew point, solar output, precipitation. The model for the enclosure can also be updated based on additional information and data such as historical weather data such as temperature, humidity, wind, solar output and precipitation, occupancy data, such as predicted and/or detected occupancy data, calendar data, and data from the one or more weather condition sensors that sense current parameters such as temperature, humidity, wind, precipitation, and/or solar output.