Abstract: Systems and methods are disclosed for analyzing building sensor information and decomposing the information therein to a more manageable and more useful form. Certain embodiments integrate energy-based and spectral-based analysis methods with parameter sampling and uncertainty/sensitivity analysis to achieve a more comprehensive perspective of building behavior. The results of this analysis may be presented to a user via a plurality of visualizations and/or used to automatically adjust certain building operations. In certain embodiments, advanced spectral techniques, including Koopman-based operations, are employed to discern features from the collected building sensor data.

Abstract: Systems and methods are disclosed for analyzing building sensor information and decomposing the information therein to a more manageable and more useful form. Certain embodiments integrate energy-based and spectral-based analysis methods with parameter sampling and uncertainty/sensitivity analysis to achieve a more comprehensive perspective of building behavior. The results of this analysis may be presented to a user via a plurality of visualizations and/or used to automatically adjust certain building operations. In certain embodiments, advanced spectral techniques, including Koopman-based operations, are employed to discern features from the collected building sensor data.

Abstract: A method of sanitizing pipes, etc. in a hot water supply system includes the steps of normally heating water by driving water from a water storage tank, into a heat exchanger. Typically, a water pump is stopped once the water storage tank receives a particular percentage of hot water. However, when a sanitation mode is desired, the pump is not stopped, such that the water tank becomes all, or almost all, hot water. The hot water is then delivered to the pump, and from the pump to the heat exchanger. This hot water is thus operable to sanitize pipes and the pump.

Abstract: Systems and methods are disclosed for analyzing building sensor information and decomposing the information therein to a more manageable and more useful form. Certain embodiments integrate energy-based and spectral-based analysis methods with parameter sampling and uncertainty/sensitivity analysis to achieve a more comprehensive perspective of building behavior. The results of this analysis may be presented to a user via a plurality of visualizations and/or used to automatically adjust certain building operations. In certain embodiments, advanced spectral techniques, including Koopman-based operations, are employed to discern features from the collected building sensor data.

Abstract: A method of controlling a startup operation in a heat pump water heater system prevents inadvertent shutdowns and/or low operating efficiencies via closed loop control of the system. The method includes choosing an expansion valve opening at startup near an expected steady state value to ensure high system capacity as early as possible, setting a water pump signal to a high level to maximize cycle efficiency during warm-up, and applying closed loop control over the expansion valve and the water pump to increase the pressure in the system in a controlled manner until the system reaches a steady operating state. The method provides stable startup control even if a transcritical vapor compression system is used as the heat pump.

Abstract: A refrigerant cycle is provided with a control for an expansion device to achieve a desired compressor discharge pressure. The system operates transcritically, such that greater freedom over compressor discharge pressure is provided. The system's efficiency is optimized by selecting an optimum discharge pressure. The optimum discharge pressure is selected based upon sensed environmental conditions, and the expansion device is adjusted to achieve the desired compressor discharge pressure. A feedback loop may be provided to sense the actual compressor discharge pressure and adjust the actual compressor discharge pressure by further refining the expansion device. The system is disclosed providing heated water based upon a demand for a particular hot water temperature.

Abstract: An energy-efficient heat pump water heating system determines whether to energize a heat pump by interpreting readings from one or temperature sensors based on two thresholds. The heat pump is energized if the detected temperature falls below a first threshold and de-energized when the detected temperature rises above a second threshold. The thresholds may correspond to outputs of two or more sensors. Using multiple temperature thresholds improves the temperature sensing capabilities of the system, thereby improving energy efficiency by matching heat pump operation with hot water demand more closely than previously known systems.

Abstract: A PID control for a vapor compression system utilized to heat water identifies a particular range of error signals and derivative of the error signals that could be indicative of the cycle moving in an inefficient direction. If this determination is made, then a substitute for the error signal is utilized. In particular, the determination is made if both the error and the derivative of the error are negative. The substitute multiplies the error with its derivative to result in a positive product. This ensures the system will not move in the inefficient direction.

Abstract: A method of controlling a startup operation in a heat pump water heater system prevents inadvertent shutdowns and/or low operating efficiencies via closed loop control of the system. The method includes choosing an expansion valve opening at startup near an expected steady state value to ensure high system capacity as early as possible, setting a water pump signal to a high level to maximize cycle efficiency during warm-up, and applying closed loop control over the expansion valve and the water pump to increase the pressure in the system in a controlled manner until the system reaches a steady operating state. The method provides stable startup control even if a transcritical vapor compression system is used as the heat pump.

Abstract: A method of controlling a startup operation in a heat pump water heater system prevents inadvertent shutdowns and/or low operating efficiencies via closed loop control of the system. The method includes choosing an expansion valve opening at startup near an expected steady state value to ensure high system capacity as early as possible, setting a water pump signal to a high level to maximize cycle efficiency during warm-up, and applying closed loop control over the expansion valve and the water pump to increase the pressure in the system in a controlled manner until the system reaches a steady operating state. The method provides stable startup control even if a transcritical vapor compression system is used as the heat pump.

Abstract: A method of sanitizing pipes, etc. in a hot water supply system includes the steps of normally heating water by driving water from a water storage tank, into a heat exchanger. Typically, a water pump is stopped once the water storage tank receives a particular percentage of hot water. However, when a sanitation mode is desired, the pump is not stopped, such that the water tank becomes all, or almost all, hot water. The hot water is then delivered to the pump, and from the pump to the heat exchanger. This hot water is thus operable to sanitize pipes and the pump.

Abstract: A method of detecting and diagnosing operating conditions for a heat pump water heating system includes the steps of monitoring system operating conditions and comparing actual operating conditions to predicted operating conditions. The predicted operating conditions are based on expected pressures and temperatures given current system inputs. A difference between the actual and expected values for refrigerant pressures and temperature outside a desired range provides indication of a fault in the system. The system controller initiates a prompt to alert of the need for maintenance and direct to potential causes.

Abstract: A control particularly useful for a hot water heating system, includes calculation of a desired leaving water temperature for water leaving a hot water heat exchanger, and a desired refrigerant condition for most efficiently achieving the desired leaving water temperature. A control looks at both desired variables and compares them to actual variables to determine an error for each. The control includes an error correction algorithm for each of the two variables that takes into account both of the errors, the integral of both of the errors, and the derivative of both of the errors. In this way, sensitivity in the error correction for one variable due to changes in the other variable is reduced, and the system functions more efficiently.

Abstract: A method of detecting and diagnosing operating conditions for a heat pump water heating system includes the steps of monitoring system operating conditions and comparing actual operating conditions to predicted operating conditions. The predicted operating conditions are based on expected pressures and temperatures given current system inputs. A difference between the actual and expected values for refrigerant pressures and temperature outside a desired range provides indication of a fault in the system. The system controller initiates a prompt to alert of the need for maintenance and direct to potential causes.

Abstract: A refrigerant cycle is provided with a control for an expansion device to achieve a desired compressor discharge pressure. The system operates transcritically, such that greater freedom over compressor discharge pressure is provided. The system's efficiency is optimized by selecting an optimum discharge pressure. The optimum discharge pressure is selected based upon sensed environmental conditions, and the expansion device is adjusted to achieve the desired compressor discharge pressure. A feedback loop may be provided to sense the actual compressor discharge pressure and adjust the actual compressor discharge pressure by further refining the expansion device. The system is disclosed providing heated water based upon a demand for a particular hot water temperature.

Abstract: A PID control for a vapor compression system utilized to heat water identifies a particular range of error signals and derivative of the error signals that could be indicative of the cycle moving in an inefficient direction. If this determination is made, then a substitute for the error signal is utilized. In particular, the determination is made if both the error and the derivative of the error are negative. The substitute multiplies the error with its derivative to result in a positive product. This ensures the system will not move in the inefficient direction.

Abstract: A control particularly useful for a hot water heating system, includes calculation of a desired leaving water temperature for water leaving a hot water heat exchanger, and a desired refrigerant condition for most efficiently achieving the desired leaving water temperature. A control looks at both desired variables and compares them to actual variables to determine an error for each. The control includes an error correction algorithm for each of the two variables that takes into account both of the errors, the integral of both of the errors, and the derivative of both of the errors. In this way, sensitivity in the error correction for one variable due to changes in the other variable is reduced, and the system functions more efficiently.

Abstract: An energy-efficient heat pump water heating system determines whether to energize a heat pump by interpreting readings from one or temperature sensors based on two thresholds. The heat pump is energized if the detected temperature falls below a first threshold and de-energized when the detected temperature rises above a second threshold. The thresholds may correspond to outputs of two or more sensors. Using multiple temperature thresholds improves the temperature sensing capabilities of the system, thereby improving energy efficiency by matching heat pump operation with hot water demand more closely than previously known systems.

Abstract: A method of controlling a startup operation in a heat pump water heater system prevents inadvertent shutdowns and/or low operating efficiencies via closed loop control of the system. The method includes choosing an expansion valve opening at startup near an expected steady state value to ensure high system capacity as early as possible, setting a water pump signal to a high level to maximize cycle efficiency during warm-up, and applying closed loop control over the expansion valve and the water pump to increase the pressure in the system in a controlled manner until the system reaches a steady operating state. The method provides stable startup control even if a transcritical vapor compression system is used as the heat pump.

Abstract: A vapor compression system includes a compressor, a gas cooler, an expansion device, and an evaporator. Refrigerant is circulated through the closed circuit cycle. Preferably, carbon dioxide is used as the refrigerant. Adaptive control is employed to optimize the coefficient of performance of the vapor compression system. As the system changes over time, a model that operates the system is modified. The model is determined by an adaptive control algorithm including variable coefficients. As the model changes, the variables of the adaptive control algorithm change. A control of the gas cooler is then adjusted to regulate the high pressure of the system, and therefore the coefficient of performance. In a first example, Least Mean Squares (LMS) is used to modify the variables of the adaptive control algorithm to optimize the coefficient of performance. In a second example, the coefficient of performance is optimized by a slowly varying periodic excitation method.