Abstract: A method and system is disclosed for scaling performance indicators of control applications in an environmental control system. The method and system include receiving more than one performance indicator from a first control application, wherein the first control application includes a modulating control output and receiving more than one performance indicator from a second control application, wherein the second control application includes a staged-control output. The method and system further include identifying a probability distribution, wherein the probability distribution is characteristic of a fault-free environmental control system and calculating probability distributions associated with the performance indicators of the first and second control applications. The method and system also include displaying the probability distributions of the first and second control applications on a common scale.

Abstract: Systems and methods to regulate the amount of outdoor air that is introduced into a building. These systems and methods determine the mechanical load requirements based on adaptive control functionality. These systems and methods utilize extremum seeking control logic to vary the flow of outdoor air into the building in response to these load determinations.

Abstract: Systems and methods to regulate the amount of outdoor air that is introduced into a building. These systems and methods use the cooling coil control signal which is a function of the load on the cooling coil. These systems and methods utilize extremum seeking control logic to vary the flow of outdoor air into the building in response to these load determinations.

Abstract: A method for determining vibration amplitude limits of a mechanical device. The method comprises identifying a mechanical device and a frequency range for a spectrum to be analyzed, retrieving vibration spectra comprising individual spectrum for the mechanical device and the frequency range, calculating frequency for the individual spectrum, and identifying the individual spectrum with the smallest number of frequency lines. In addition, the method comprises calculating noise bandwidths and a largest noise bandwidth, removing outlier data, calculating conditional kernel density, and calculating vibration amplitude limits to detect faults in the mechanical device.

Abstract: A method and apparatus is disclosed for assessing performance of control applications in an environmental control network and for diagnosing performance problems. The apparatus includes a performance assessment and diagnostic display comprising a facility navigation tree, a system navigation tree and a performance/diagnostics window. The facility navigation tree and system navigation tree may be used to select the facilities and systems that are to have their associated control applications assessed and/or diagnosed. The performance/diagnostics window includes graphs of performance indictors that are indicative of performance levels for the included control applications. The system tree may be used to delve to more detailed views of the performance indicators to obtain additional information that may help to diagnose problems noted in performance of the selected control applications.

Abstract: A pattern recognition adaptive controller configured to dynamically adjust proportional gain and integral time control parameters based upon patterns that characterize the closed-loop response. The pattern recognition adaptive controller receives a sampled signal representative of the controlled variable, and determines a smoothed signal based on the sampled signal. The controller determines an estimated noise level of the sampled signal and determines if the control output and process output are oscillating quickly based on predefined criteria. The controller adjusts the gain used by the controller if the control output and process output are oscillating quickly. If the control output and process are not oscillating quickly, the controller determines whether there has been a significant load disturbance, whether there is an insignificant pattern, and/or whether the control output is saturated.

Abstract: A method and apparatus are provided for filling a gap of missing data using source specified data. The method includes analyzing a first set of data representative of utility consumption for a plurality of days to determine clusters of days of the week having similar utility consumption. The method further includes generating an individual profile of utility consumption for each cluster, and copying data from at least one individual profile into the gap to form a second set of data without any gaps. A system for filling a gap of missing data using source specified data includes a microprocessor programmed to copy data from at least one individual profile into the gap, and to adjust the copied data up or down to account for local trend information adjacent to the gap.

Abstract: Outlier identification is employed to detect abnormally high or low energy use in a building. The utility use is measured periodically throughout each day and the measurements are grouped according to days that have similar average utility consumption levels. The data in each group is statistically analyzed using the Generalized Extreme Studentized Deviate (GESD) method. That method identifies outliers which are data samples that vary significantly from the majority of the data. The degree to which each outlier deviates from the remainder of the data indicates the severity of the abnormal utility consumption denoted by that outlier. The resultant outlier information is readily discernable by the building operators in accessing whether the cause of a particular occurrence of abnormal utility usage requires further investigation.

Abstract: A refrigeration system (10) has a compressor (12) that forces a refrigerant to flow in a loop between an evaporator (17) and a condenser (16). The present method controls the speed of a condenser fan (16) in response to the condenser temperature. In a first control state, the speed of the fan (16) is varied in response to the condenser temperature. In a second state, the fan (16) is turned on and off by a pulse width modulated signal that has a duty cycle which varies in response to the condenser temperature. A transition occurs from the first state to the second state when the fan (16) operates at the slowest possible speed for a predetermined period while the condenser temperature is below a desired value. A transition occurs from the second state to the first state when the duty cycle is at 100% for a given period and the condenser temperature is above the desired value.

Abstract: A method and apparatus for determining days of the week with similar consumption of energy or utility by a computerized system utilizes a pattern recognition algorithm. The algorithm utilizes a time series of energy or utility use data spanning a plurality of days to generate at least one feature of interest for each day. The features of interest may be any or all of average daily utility consumption, maximum utility use during a predefined time interval for the day, minimum utility use over the predefined time interval for the day, and the like. The algorithm transforms the at least one feature of interest for each day to remove the effects of any seasonal variation that may be present in the time series data. The features of interest are then grouped by day of the week to define seven clusters. The algorithm next performs an outlier analysis for each feature of interest in each of the seven clusters to identify and remove any abnormal data.

Abstract: Outlier identification is employed to detect abnormally high or low energy use in a building. The utility use is measured periodically throughout each day and the measurements are grouped according to days that have similar average utility consumption levels. The data in each group is statistically analyzed using the Generalized Extreme Studentized Deviate (GESD) method. That method identifies outliers which are data samples that vary significantly from the majority of the data. The degree to which each outlier deviates from the remainder of the data indicates the severity of the abnormal utility consumption denoted by that outlier. The resultant outlier information is readily discernable by the building operators in accessing whether the cause of a particular occurrence of abnormal utility usage requires further investigation.

Abstract: A method is disclosed for programming and executing a state machine control program represented as a diagram in an HVAC controller. The diagram is converted to tabular data which is entered into one or more spreadsheet pages. The tabular data includes the defined output states, the defined input states and defined transition states, whereby a given output state and a given set of inputs will cause transition to a next output state. The tabular data is translated, through execution of a routine in a macro-instruction language, into a plurality of data structures for downloading into a finite state machine object data structure in the controller, where it will be acted upon by an object-oriented execution module, referred to as a class execute method, which is also present in the controller.

Abstract: A strategy for controlling an air side economizer of an HVAC system uses a model of the airflow through the system to estimate the load in two modes when minimum and maximum amounts of outdoor air are being introduced into the building. Transitions between minimum outdoor air and maximum outdoor air usage occur based on those estimated loads, which in a preferred embodiment are cooling loads. The second embodiment of this economizer control strategy uses the model and a one-dimensional optimization routine to determine the fraction of outdoor air that minimizes the load on the HVAC system.

Abstract: The present invention provides a sequencing control strategy for environmental system controllers that takes better advantage of the capabilities of the system elements to enhance performance and reduce operating costs. Digital controller technology is included and operates in accordance with a state transition diagram clarifying conditions that must exist for the environmental controller to switch from one mode of operation to another (e.g., from a cooling mode with dampers set at the minimum position to a cooling mode with the dampers modulating to reduce the energy used for mechanical cooling). Several a controllers, or a single controller operating on several sets of control parameters, sequentially operate in accordance with transition data and system performance characteristics for controlling system operation.

Abstract: A facilities management system is subdivided into a plurality of subsystems. The performance of the system is monitored by producing data which denotes a plurality of operational parameters for each of the subsystems. From that data, a global performance index is derived for each subsystem, thus providing an indication of each subsystem's performance. The global performance indices are employed to produce a universal performance index for the entire facilities management system. This provides a hierarchy of data which enables an operator to quickly determine the overall performance of the facilities management system and each subsystem, and if warranted the operator can step through the data to identify malfunctioning components.

Abstract: A system and method of controlling air quality within a room. The method includes determining a first discharge air temperature setpoint based upon a room temperature setpoint and a first value indicative of an air temperature within the room, and determining a first air flow control signal based upon the first discharge air temperature setpoint and a second value indicative of an air temperature of discharge air being provided into the room. The method further includes controlling an air flow device based upon the first air flow control signal, and maintaining a heating device employed to influence the air temperature of the discharge air at a maximum heating level. The method additionally includes monitoring a level of carbon dioxide within the room to determine whether the level is below a predetermined threshold.

Abstract: The flow air from a hot air duct and a cold air duct into a zone of a building is controlled in based upon performing a thermal energy balance calculation for the zone. That calculation produces a heat transfer setpoint from which a hot air flow setpoint and a cold air flow setpoint are derived. The hot and cold air flow setpoints respectively control the flow of air through the hot and cold air ducts.

Abstract: Fault detection is implemented on a finite state machine controller for an air handling system. The method employs data, regarding the system performance in the current state and upon a transition occurring, to determine whether a fault condition exists. The fault detection may be based on saturation of the system control or on a comparison of actual performance to a mathematical model of the air handling system. As a consequence, the control does not have to be in steady-state operation to perform fault detection.

Abstract: The present invention provides a sequencing control strategy for environmental system controllers that takes better advantage of the capabilities of the system elements to enhance performance and reduce operating costs. A state machine controller is implemented by employing digital technology which enables greater accuracy in monitoring system performance and performing diagnostics. This control modality also provides greater tolerance of faults by permitting automatic reconfiguration of the control strategy so as to be independent of malfunctioning components.

Abstract: A closed loop feedback control system operates to maintain a process variable at or near a process variable setpoint. A digital filter is implemented with the controller to filter the process variable signal input to the controller. The filter includes both an amplitude filter to clip signal spikes and glitches and low pass filter to remove higher order, noise related frequencies from the signal, that could adversely affect computational speed of the controller.