Abstract: A cooler system includes a plurality of cooler units; a condensed water flow path, an aqueous medium in the condensed water flow path sequentially flowing through each of the cooler units; a cooling water flow path, an aqueous medium in the cooling water flow path sequentially flowing through each of the cooler units in a flow direction opposite to a flow direction of the aqueous medium in the condensed water flow path; a plurality of current sensors used for detecting working currents of the cooler units; water temperature sensors used for detecting an entering water temperature and a leaving water temperature of the cooling water flow path; at least one virtual temperature sensor arranged between the cooler units and used for acquiring a middle water temperature between the cooler units; and a controller.

Abstract: Heat pump systems and methods of operating including a first unit having a first unit heat exchanger, a compressor, an accumulator, and a first unit expansion valve, a second unit fluidly connected to the first unit by piping, the second unit having a second unit heat exchanger, and a system controller, the system controller having (I) a PID control element receiving as inputs (i) gain scheduling, (ii) an error signal, and (iii) feedback relating to an opening command of the first unit expansion valve, and (II) a feedforward control element generating a feedforward term that is combined with an output of the PID control element to generate the opening command of the first unit expansion valve. The system controller controls an opening of the first unit expansion valve using the opening command of the first unit expansion valve.

Abstract: Heat pump systems and methods of operating including a first unit having a first unit heat exchanger, a compressor, an accumulator, and a first unit expansion valve, a second unit fluidly connected to the first unit by piping, the second unit having a second unit heat exchanger, and a system controller, the system controller having (I) a PID control element receiving as inputs (i) gain scheduling, (ii) an error signal, and (iii) feedback relating to an opening command of the first unit expansion valve, and (II) a feedforward control element generating a feedforward term that is combined with an output of the PID control element to generate the opening command of the first unit expansion valve. The system controller controls an opening of the first unit expansion valve using the opening command of the first unit expansion valve.

Abstract: An environmental control system is provided and includes equipment to generate an environmental control effect, a damper associated with a zone to control a portion of the environmental control effect permitted to affect the zone by assuming one of various damper positions and a capacity controller operably coupled to the equipment and the damper to control operation of the equipment and to adjust the damper to assume the one of the various damper positions based on a demand of the zone and a capacity of the equipment.

Abstract: A cooler system includes a plurality of cooler units; a condensed water flow path, an aqueous medium in the condensed water flow path sequentially flowing through each of the cooler units; a cooling water flow path, an aqueous medium in the cooling water flow path sequentially flowing through each of the cooler units in a flow direction opposite to a flow direction of the aqueous medium in the condensed water flow path; a plurality of current sensors used for detecting working currents of the cooler units; water temperature sensors used for detecting an entering water temperature and a leaving water temperature of the cooling water flow path; at least one virtual temperature sensor arranged between the cooler units and used for acquiring a middle water temperature between the cooler units; and a controller.

Abstract: A method and apparatus for controlling an HVAC system. The method may include receiving a fan speed signal from a fan control loop, and choosing among an independent mode, a first linked mode, and a second linked mode, depending on the fan speed signal. The method may also include providing a signal to a pressure control loop to reduce a speed of a supply air fan of an AHU, when the first linked mode is chosen. The method may further include providing a signal to a temperature control loop to decrease a speed of a heat exchange wheel, to decrease a flow rate of a heat exchange fluid to an evaporator coil, or both, when the second linked mode is chosen. The method may additionally include allowing the fan control loop to operate independently of the temperature and pressure control loops, when the independent mode is chosen.

Abstract: A system includes a heat pump configured to match a working heat transfer fluid temperature to a fluid temperature set-point, a fluid pump in fluid communication with the heat pump through the heat transfer fluid and configured to match the heat transfer fluid pressure/flow to a fluid pressure/flow set-point, at least one heat exchanger in fluid communication with the fluid pump, and a supervisory controller in signal communication with the at least one heat exchanger, the fluid pump, and the heat pump. The at least one heat exchanger includes a proportional valve and a return air temperature gauge configured to monitor return air temperature associated therewith. The supervisory controller is configured to vary the fluid temperature set-point and vary the fluid pressure/flow set-point based upon a position of the proportional valve and the return air temperature.

Abstract: An environmental control system is provided and includes equipment to generate an environmental control effect, a damper associated with a zone to control a portion of the environmental control effect permitted to affect the zone by assuming one of various damper positions and a capacity controller operably coupled to the equipment and the damper to control operation of the equipment and to adjust the damper to assume the one of the various damper positions based on a demand of the zone and a capacity of the equipment.

Abstract: Systems and methods for autotuning a HVAC system controller. The method may include receiving a performance coefficient and providing a step-input using an autotuner relay to measure ultimate gain and ultimate period in a controlled HVAC system. The method may also include adjusting the ultimate gain and ultimate period to account for a relay hysteresis, and applying a tuning rule to derive a proportional gain and an integral time for a controller of the HVAC system control loop. The method may further include updating the controller with the proportional gain and integral time, and verifying the proportional gain and integral time. Verifying the proportional gain and integral time may include setting a performance envelope having a tightness related to the performance coefficient, applying a step-input to provoke a closed-loop response, and comparing the closed loop response with the performance envelope to determine whether the closed-loop response is within the envelope.

Abstract: An environmental control system is provided and includes equipment to generate an environmental control effect, a damper associated with a zone to control a portion of the environmental control effect permitted to affect the zone by assuming one of various damper positions and a capacity controller operably coupled to the equipment and the damper to control operation of the equipment and to adjust the damper to assume the one of the various damper positions based on a demand of the zone and a capacity of the equipment.

Abstract: An environmental control system is provided and includes equipment to generate an environmental control effect, a damper associated with a zone to control a portion of the environmental control effect permitted to affect the zone by assuming one of various damper positions and a capacity controller operably coupled to the equipment and the damper to control operation of the equipment and to adjust the damper to assume the one of the various damper positions based on a demand of the zone and a capacity of the equipment.

Abstract: A system for controlling an absorption chiller includes feedback control loops determining adjustments to system cooling and heating capacities and a controller for simultaneously adjusting positions of an energy input valve, a hot water valve, and a chilled water valve. The controller adjusts valves based on desired adjustments to system cooling and heating capacities and performance maps characterizing relationships between cooling capacity and heating capacities and valve positions. A method for controlling an absorption chiller includes the step of obtaining a performance map characterizing heat energy input to cooling and heating loops as functions of valve positions. To obtain the map, the hot water valve is held in a substantially constant position while the chilled water valve is modulated. Similarly, the hot water valve is modulated while the chilled water valve is held in a substantially constant position.

Abstract: A method is provided for the automated setup of a metered combustion control system for controlling operation of a boiler combustion system. The automated setup process includes both commissioning and controller tuning, rather than tuning the carbon monoxide and/or oxygen trim controller after the commissioning process has been completed. The oxygen trim controller or the carbon monoxide trim controller is used to identify the air/fuel ratio.

Abstract: A method and apparatus for controlling an HVAC system. The method may include receiving a fan speed signal from a fan control loop, and choosing among an independent mode, a first linked mode, and a second linked mode, depending on the fan speed signal. The method may also include providing a signal to a pressure control loop to reduce a speed of a supply air fan of an AHU, when the first linked mode is chosen. The method may further include providing a signal to a temperature control loop to decrease a speed of a heat exchange wheel, to decrease a flow rate of a heat exchange fluid to an evaporator coil, or both, when the second linked mode is chosen. The method may additionally include allowing the fan control loop to operate independently of the temperature and pressure control loops, when the independent mode is chosen.

Abstract: Systems and methods for autotuning a HVAC system controller. The method may include receiving a performance coefficient and providing a step-input using an autotuner relay to measure ultimate gain and ultimate period in a controlled HVAC system. The method may also include adjusting the ultimate gain and ultimate period to account for a relay hysteresis, and applying a tuning rule to derive a proportional gain and an integral time for a controller of the HVAC system control loop. The method may further include updating the controller with the proportional gain and integral time, and verifying the proportional gain and integral time. Verifying the proportional gain and integral time may include setting a performance envelope having a tightness related to the performance coefficient, applying a step-input to provoke a closed-loop response, and comparing the closed loop response with the performance envelope to determine whether the closed-loop response is within the envelope.

Abstract: A system includes a heat pump configured to match a working fluid's temperature to a fluid temperature set-point, a fluid pump in fluid communication with the heat pump through the working fluid and configured to match the working fluid's pressure/flow to a fluid pressure/flow set-point, at least one heat exchanger in fluid communication with the fluid pump, and a supervisory controller in signal communication with the at least one heat exchanger, the fluid pump, and the heat pump. The at least one heat exchanger includes a proportional valve and a return air temperature gauge configured to monitor return air temperature associated therewith. The supervisory controller is configured to vary the fluid temperature set-point and vary the fluid pressure/flow set-point based upon a position of the proportional valve and the return air temperature.

Abstract: A method is provided for commissioning a combustion control system for controlling operation of a boiler combustion system. The method includes the step of mapping a plurality of sets of coordinated servo positions for the fuel flow control device and the air flow control device at a plurality of selected firing rate points between a minimum firing rate and a maximum firing rate by using an algorithm and an iterative process to identify the coordinated air and fuel actuator positions instead of a trial and error method.

Abstract: A method is provided for tuning an oxygen trim controller during the commissioning of a combustion control system for controlling operation of a boiler combustion system, rather than tuning the oxygen trim controller after the commissioning process has been completed.

Abstract: A system for controlling an absorption chiller includes feedback control loops determining adjustments to system cooling and heating capacities and a controller for simultaneously adjusting positions of an energy input valve, a hot water valve, and a chilled water valve. The controller adjusts valves based on desired adjustments to system cooling and heating capacities and performance maps characterizing relationships between cooling capacity and heating capacities and valve positions. A method for controlling an absorption chiller includes the step of obtaining a performance map characterizing heat energy input to cooling and heating loops as functions of valve positions. To obtain the map, the hot water valve is held in a substantially constant position while the chilled water valve is modulated. Similarly, the hot water valve is modulated while the chilled water valve is held in a substantially constant position.

Abstract: A method and system for operating a CO2 refrigeration system is provided. Two pressures are controlled by two controllers through two valves in this system. A first valve is actuated by a first controller using a first transfer function in response to the first measured pressure. A second valve is actuated by a second controller using a second transfer function in response to the second measured pressure. When it is determining the second valve failed to operate correctly, the first valve is actuated by a third controller using a third transfer function.