Abstract: Systems, apparatus and methods for efficiently operating a chiller plant while minimizing or eliminating the occurrence of centrifugal compressor surge. Taking into account chiller design specifications and current operating conditions, a compressor lift point at which surge is predicted to occur is established. Minima and maxima for various chiller setpoints that avoid or eliminate the occurrence of compressor surge are imposed on setpoints provided by a conventional optimizing chiller controller. The chiller system is operated in accordance with the resultant anti-surge setpoints. Energy savings is realized by modulating coolant tower flow to enable the compressor to operate at near-surge conditions while preventing the onset of actual surge.

Abstract: A method for estimating refrigerant charge for an HVACR system is provided. The method includes obtaining one or more system parameters during operation. The one or more system parameters include at least one of compressor suction superheat, system mass flow, expansion device mass flow or opening degree, compressor suction saturated temperature, and compressor discharge saturated temperature. The method also includes conducting a regression analysis on the one or more system parameters to determine one or more predictive parameters for estimating the refrigerant charge. The method further includes determining a predictive model based on regression analysis. The predictive model establishes a relationship between the refrigerant charge and the one or more predictive parameters. Also the method includes estimating the refrigerant charge based on the predictive model.

Abstract: Disclosed are techniques relating to an improved air quality device that can provide personalized comfort and improved air quality elements to occupants of a common space. The improved air quality device can comprise a plurality of individually adjustable directional outlets. The state of these individually adjustable directional outlets can be updated to individually satisfy comfort levels of various occupants at different locations within the common space, which can be determined based on inputs from a control device (e.g., thermostat), a sensor (e.g., occupancy sensor), and so forth. The improved air quality device can further comprise an ultraviolet light device that can reduce pathogens in the common space. The state of the ultraviolet light device (e.g., on/off, duration of on/off, a position/location, and so on) can be a function of the state of the state of the outlets.

Abstract: A method for estimating refrigerant charge for an HVACR system is provided. The method includes obtaining one or more system parameters during operation. The one or more system parameters include at least one of compressor suction superheat, system mass flow, expansion device mass flow or opening degree, compressor suction saturated temperature, and compressor discharge saturated temperature. The method also includes conducting a regression analysis on the one or more system parameters to determine one or more predictive parameters for estimating the refrigerant charge. The method further includes determining a predictive model based on regression analysis. The predictive model establishes a relationship between the refrigerant charge and the one or more predictive parameters. Also the method includes estimating the refrigerant charge based on the predictive model.

Abstract: Disclosed are techniques relating to an improved air quality device that can provide personalized comfort and improved air quality elements to occupants of a common space. The improved air quality device can comprise a plurality of individually adjustable directional outlets. The state of these individually adjustable directional outlets can be updated to individually satisfy comfort levels of various occupants at different locations within the common space, which can be determined based on inputs from a control device (e.g., thermostat), a sensor (e.g., occupancy sensor), and so forth. The improved air quality device can further comprise an ultraviolet light device that can reduce pathogens in the common space. The state of the ultraviolet light device (e.g., on/off, duration of on/off, a position/location, and so on) can be a function of the state of the state of the outlets.

Abstract: A method for estimating refrigerant charge for an HVACR system is provided. The method includes obtaining one or more system parameters during operation. The one or more system parameters include at least one of compressor suction superheat, system mass flow, expansion device mass flow or opening degree, compressor suction saturated temperature, and compressor discharge saturated temperature. The method also includes conducting a regression analysis on the one or more system parameters to determine one or more predictive parameters for estimating the refrigerant charge. The method further includes determining a predictive model based on regression analysis. The predictive model establishes a relationship between the refrigerant charge and the one or more predictive parameters. Also the method includes estimating the refrigerant charge based on the predictive model.

Abstract: Systems, apparatus and methods for efficiently operating a chiller plant while minimizing or eliminating the occurrence of centrifugal compressor surge. Taking into account chiller design specifications and current operating conditions, a compressor lift point at which surge is predicted to occur is established. Minima and maxima for various chiller setpoints that avoid or eliminate the occurrence of compressor surge are imposed on setpoints provided by a conventional optimizing chiller controller. The chiller system is operated in accordance with the resultant anti-surge setpoints. Energy savings is realized by modulating coolant tower flow to enable the compressor to operate at near-surge conditions while preventing the onset of actual surge.

Abstract: Systems, apparatus and methods for operating a chiller plant while minimizing or eliminating the occurrence of centrifugal compressor surge. Taking into account chiller design specifications and current operating conditions, a compressor lift point at which surge is predicted to occur is established. Minima and maxima for various chiller setpoints that avoid or eliminate the occurrence of compressor surge are imposed on setpoints provided by a conventional optimizing chiller controller. The chiller system is operated in accordance with the resultant anti-surge setpoints. Coolant tower flow is modulated to enable the compressor to operate at near-surge conditions while preventing the onset of actual surge.

Abstract: Systems, apparatus and methods for providing personalized comfort to occupants of a conditioned space. A precision air device having a standalone controllable fan with directional nozzles is provided. The precision air device includes environmental and occupancy sensors, and communicates with a user device and with other precision air devices in the space. Application software installed on an occupant's user device enables the occupant to specify whether it is too cold or too warm within his or her personal space, or microzone. The collective demand of all microzones within a VAV macrozone is determined by a precision air aggregator to adjust a controllable VAV damper for that macrozone.

Abstract: Systems, apparatus and methods for efficiently operating a chiller plant while minimizing or eliminating the occurrence of centrifugal compressor surge. Taking into account chiller design specifications and current operating conditions, a compressor lift point at which surge is predicted to occur is established. Minima and maxima for various chiller setpoints that avoid or eliminate the occurrence of compressor surge are imposed on setpoints provided by a conventional optimizing chiller controller. The chiller system is operated in accordance with the resultant anti-surge setpoints. Energy savings is realized by modulating coolant tower flow to enable the compressor to operate at near-surge conditions while preventing the onset of actual surge.

Abstract: Systems, apparatus and methods for providing personalized comfort to occupants of a conditioned space. A precision air device having a standalone controllable fan with directional nozzles is provided. The precision air device includes environmental and occupancy sensors, and communicates with a user device and with other precision air devices in the space. Application software installed on an occupant's user device enables the occupant to specify whether it is too cold or too warm within his or her personal space, or microzone. The collective demand of all microzones within a VAV macrozone is determined by a precision air aggregator to adjust a controllable VAV damper for that macrozone.

Abstract: A system and method for temperature control for a Transport Refrigeration System (TRS) is provided. Particularly, a method for temperature control of an internal space of a refrigerated transport unit is provided. The method includes determining a measured internal space temperature within the internal space of the refrigerated transport unit. The method also includes calculating, via a TRS controller, a temperature difference between the measured internal space temperature and a desired set point temperature. Also, the method includes adjusting, via the TRS controller, a duty cycle percentage of a liquid line solenoid valve and/or a hot gas solenoid valve based on the temperature difference to control an amount of refrigerant directed to the thermal expansion device and the evaporator and/or an amount of hot gas directed to the evaporator.

Abstract: Systems, apparatus and methods for providing personalized comfort to occupants of a conditioned space. A precision air device having a standalone controllable fan with directional nozzles is provided. The precision air device includes environmental and occupancy sensors, and communicates with a user device and with other precision air devices in the space. Application software installed on an occupant's user device enables the occupant to specify whether it is too cold or too warm within his or her personal space, or microzone. The collective demand of all microzones within a VAV macrozone is determined by a precision air aggregator to adjust a controllable VAV damper for that macrozone.

Abstract: A method for estimating refrigerant charge for an HVACR system is provided. The method includes obtaining one or more system parameters during operation. The one or more system parameters include at least one of compressor suction superheat, system mass flow, expansion device mass flow or opening degree, compressor suction saturated temperature, and compressor discharge saturated temperature. The method also includes conducting a regression analysis on the one or more system parameters to determine one or more predictive parameters for estimating the refrigerant charge. The method further includes determining a predictive model based on regression analysis. The predictive model establishes a relationship between the refrigerant charge and the one or more predictive parameters. Also the method includes estimating the refrigerant charge based on the predictive model.

Abstract: Systems, apparatus and methods for providing personalized comfort to occupants of a conditioned space. A precision air device having a standalone controllable fan with directional nozzles is provided. The precision air device includes environmental and occupancy sensors, and communicates with a user device and with other precision air devices in the space. Application software installed on an occupant's user device enables the occupant to specify whether it is too cold or too warm within his or her personal space, or microzone. The collective demand of all microzones within a VAV macrozone is determined by a precision air aggregator to adjust a controllable VAV damper for that macrozone.

Abstract: The embodiments disclosed herein are directed to systems and methods to control a HVAC system based on a state of an unloader of a compressor of the HVAC system.

Abstract: A system and method for temperature control for a Transport Refrigeration System (TRS) is provided. Particularly, a method for temperature control of an internal space of a refrigerated transport unit is provided. The method includes determining a measured internal space temperature within the internal space of the refrigerated transport unit. The method also includes calculating, via a TRS controller, a temperature difference between the measured internal space temperature and a desired set point temperature. Also, the method includes adjusting, via the TRS controller, a duty cycle percentage of a liquid line solenoid valve and/or a hot gas solenoid valve based on the temperature difference to control an amount of refrigerant directed to the thermal expansion device and the evaporator and/or an amount of hot gas directed to the evaporator.

Abstract: A heat pump includes a valve system that connects a receiver tank in fluid communication with an indoor heat exchanger, wherein the valve system, operating under a novel control scheme, works in conjunction with the receiver to control the heat pump's effective refrigerant charge. To avoid suction or discharge pressure faults and to help prevent slugs of liquid refrigerant from entering the heat pump's compressor as the heat pump switches between heating and cooling modes or switches between heating and defrost modes, the control scheme provides momentary periods of transition between those modes of operation. In some embodiments, the valve system comprises a check valve connected in parallel flow relationship with a two-position receiver valve, wherein the check valve has an appreciably higher flow coefficient than that of the receiver valve.

Abstract: The embodiments disclosed herein are directed to systems and methods to control a HVAC system based on a state of an unloader of a compressor of the HVAC system.

Abstract: A reversible HVAC heating/cooling refrigerant system includes a novel valve system that allows an outdoor heat exchanger to function as a subcooler during a cooling or defrost mode and function as a receiver tank for storing excess liquid refrigerant during a heating mode. In the heating mode, a cooling expansion valve is kept slightly open to flood the subcooler with liquid refrigerant while a heating expansion valve is regulated to maintain a desired level of superheat at the suction side of the refrigerant system's compressor. The novel valve system also serves as a pressure relief valve to protect the subcooler from excess pressure caused by thermal expansion of liquid refrigerant trapped within the subcooler.