Methods and systems for coordinating the control of HVAC units
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Solution Overview
Problem
Decentralized HVAC unit controls in open-plan spaces lead to oscillating temperatures and humidity due to close sensor or unit location, sensor errors, and differing setpoints, causing inefficiency and instability, with a lack of fault tolerance if one unit fails.
Innovation Solution
A system using overlapping sets of sensors to control HVAC units, calculating change values for operational parameters based on differences with reference values, and employing a transfer matrix to weight contributions, ensuring uniform environmental conditions and fault tolerance by compensating for failed units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If decentralized standalone controls are used for each HVAC unit, then each unit can independently control its local temperature and humidity, but this causes units to fight against each other resulting in oscillating temperature and humidity and simultaneous heating and cooling
Solution Approach 1:
The patent merges the control functions of multiple decentralized HVAC units into a centralized control system that coordinates all units. The centralized controller receives temperature and humidity readings from all units and sends coordinated control signals to all units, eliminating the fighting behavior while maintaining independent control capability through unified management.
Solution Approach 2:
The system implements feedback by continuously monitoring temperature and humidity readings from all HVAC units and using this information to adjust the operation of each unit. The centralized controller processes feedback from all sensors and modifies control signals to prevent oscillations and simultaneous heating and cooling, achieving stable environmental control.
2Speed
If each HVAC unit operates with its own sensor and set points, then units can respond locally to conditions, but sensor errors and differing set points cause instability and unit-to-unit heating and cooling at the same time
Solution Approach 1:
The centralized control system performs multiple functions: it collects data from all sensors, processes temperature and humidity readings, determines optimal set points for all units, and sends control signals to all HVAC units. This universal controller eliminates the problems of individual sensor errors and differing set points by providing unified measurement and control.
Solution Approach 2:
The centralized control system acts as an intermediary between the sensors and the HVAC units. Instead of each unit directly responding to its own sensor, the centralized controller mediates by processing all sensor inputs and coordinating all unit outputs, eliminating the instability caused by individual sensor errors and conflicting set points.
3Temperature
If multiple HVAC units are deployed in close proximity, then adequate cooling coverage can be achieved, but this causes one unit to fight against another resulting in wasted energy from simultaneous heating and cooling
Solution Approach 1:
The centralized control system dynamically adjusts the operation of each HVAC unit based on real-time temperature and humidity readings. It continuously monitors the thermal state of the space and dynamically coordinates which units should be cooling, heating, or idle, eliminating energy waste from simultaneous conflicting operations while maintaining adequate cooling coverage.
Solution Approach 2:
The system changes operational parameters of the HVAC units based on coordinated control. The centralized controller adjusts temperature set points, fan speeds, and cooling capacity of each unit dynamically, ensuring that units operate in complementary rather than conflicting modes, thereby reducing energy waste while maintaining sufficient cooling coverage.
4Device complexity
If decentralized controls are used without coordination, then system complexity is reduced, but this results in oscillating conditions and lack of fault tolerance when one unit fails
Solution Approach 1:
The centralized control system serves as an intermediary that manages the complexity of coordinating multiple HVAC units. It handles all the computational burden of detecting unit failures, recalculating optimal operations, and redistributing loads among remaining units. This centralized mediation provides fault tolerance without requiring complex coordination logic in each individual unit.
Solution Approach 2:
The patent merges the fault detection and load balancing functions into the centralized control system. When a unit fails, the centralized controller detects the failure and automatically redistributes the cooling load among the remaining operational units. This merging of control functions provides fault tolerance while keeping individual units simple.
Data Source
AI summary
A control strategy for heating, ventilating, and air-conditioning (HVAC) units used to condition the environment in data centers and other commercial buildings such as retail stores with an open-plan design is provided to coordinate the operation of the actuators of the HVAC units. A supervisory controller receives feedback signals from a plurality of environmental sensors and uses a set of references values to determine control signals to the actuators of the HVAC units. A pseudoinverse of a transfer function matrix G may be used to determine the control signals from errors in the feedback signals relative to the reference signals.