Central Plant Control Envelope Ray-Casting for Stable HVAC Operation
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Solution Overview
Problem
Existing HVAC system control methods are computationally exhaustive and exhibit hysteretic behavior due to repeated enabling and disabling of devices, reducing operating efficiency.
Innovation Solution
A controller using a processing circuit that determines the operating point of HVAC devices within control regions in a multidimensional space through ray-casting, allowing efficient operation by counting the number of times a ray crosses boundaries and adjusting device speed or state accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement values are compared against all threshold values to determine device operation, then control accuracy is improved, but computational complexity increases
Solution Approach 1:
The multidimensional operating space is segmented into multiple control regions, each with its own boundary. Instead of comparing against all thresholds simultaneously, the system divides the complex decision space into manageable segments, allowing the controller to determine which region contains the operating point through systematic boundary crossing analysis rather than exhaustive comparison.
Solution Approach 2:
The patent transforms the control problem from a high-dimensional threshold comparison task into a geometric problem in multidimensional space. By representing operating parameters as coordinates and control regions as geometric volumes bounded by hyperplanes, the system uses spatial relationships (ray casting, boundary crossings) to determine control actions, reducing computational complexity while maintaining accuracy.
2Speed
If HVAC devices are repeatedly enabled and disabled based on threshold comparisons, then control responsiveness is improved, but operating efficiency deteriorates due to hysteretic behavior
Solution Approach 1:
The control system dynamically adjusts device operation based on the operating point's position within control regions. Rather than simple on/off switching at fixed thresholds, the system continuously monitors the operating point and adjusts control actions as the system transitions between regions, enabling smooth, adaptive control that responds to changing conditions without excessive cycling.
Solution Approach 2:
The system implements continuous feedback by monitoring the operating point's position relative to control region boundaries. The controller uses this feedback to determine when to change control actions, ensuring that device state changes occur only when the operating point crosses into a new control region, thereby avoiding unnecessary cycling and improving operational efficiency.
3Device complexity
If simple threshold comparison is used to control HVAC devices, then device complexity is reduced, but control precision deteriorates
Solution Approach 1:
The controller performs multiple functions through a unified approach: it simultaneously determines control actions, monitors operating state, and manages device operation through the single mechanism of operating point tracking and control region identification. This multi-functional approach maintains control precision without requiring separate complex control logic for each function.
Solution Approach 2:
The patent creates a virtual model (copy) of the physical system's operating space, representing it as a multidimensional space with control regions. This virtual model allows the controller to perform precise control decisions in the computational domain without directly manipulating physical components, thereby maintaining precision while simplifying the physical control mechanism.
Data Source
AI summary
Disclosed herein are related to a system, a method, and a non-transitory computer readable medium for controlling a central plant. In one aspect, the system obtains a control envelope for a device controlled by the controller. The control envelope comprises boundaries of a plurality of control regions in a multidimensional operating space for the device. Each control region is enclosed by a corresponding boundary. The system counts a number of times that a ray of the device crosses the boundary of a control region. The system determines whether an operating point of the device is within the control region based on the counted number. The system operates the device according to a predetermined control technique corresponding to the control region, in response to determining that the operating point of the device is within the control region.