Adaptive Feed-Forward HVAC Control for Thermal Stability

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Solution Overview

Problem

Conventional HVAC control systems rely on reactive feedback control, which leads to delay time issues causing overcompensation, oscillatory behavior, and high energy use due to non-linear behavior and varying thermal responses across different operating points, failing to provide personalized thermal comfort while minimizing energy usage effectively.

Innovation Solution

The implementation of a control system using adaptive feed-forward and feedback control loops with adaptive reference models, incorporating Micro-Electro-Mechanical Systems (MEMS) sensors for real-time data-driven modeling, and a combination of feed-forward and feedback control signals to manage thermal sources, addressing the limitations of traditional PID systems and enhancing predictive control operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional feedback control is used, then the system can respond to thermal changes, but delay time causes overcompensation and oscillatory behavior

Engineering Contradiction:
Improvecontrol stabilityVSAvoiddelay time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The feed-forward controller uses a dynamic model of the building thermal system to predict future temperature deviations and applies control actions in advance before the actual thermal disturbance occurs. This predictive approach eliminates delay time and prevents oscillatory behavior by acting proactively rather than reactively.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system combines feed-forward predictive control with feedback control to correct model inaccuracies and unmeasured disturbances. The feedback component monitors actual temperature deviations and adjusts the control signal to compensate for prediction errors, ensuring robust performance while maintaining the speed advantages of feed-forward control.

Inventive Principle:
Principle #23Feedback

2Reliability

If conventional feedback control is used, then the system can maintain thermal conditions, but it leads to high energy use due to overcompensation

Engineering Contradiction:
Improvethermal comfortVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

By predicting thermal responses using a dynamic model, the system applies control actions optimally in advance, avoiding the overcompensation inherent in conventional feedback control. This reduces unnecessary energy consumption while maintaining thermal comfort through precise, timely interventions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system adapts model parameters in real-time based on measured thermal responses and environmental conditions, optimizing control performance for varying operating points. This adaptability ensures energy-efficient control across different thermal scenarios without sacrificing comfort reliability.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional PID control is used, then the system can regulate temperature, but it fails to adapt to varying thermal responses across different operating points

Engineering Contradiction:
Improvetemperature regulationVSAvoidadaptability to operating points
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system employs a dynamic model that captures the time-varying thermal characteristics of the building across different operating conditions. Real-time adaptation of model parameters allows the controller to adjust to varying thermal responses, maintaining optimal performance whether the building is heating or cooling, occupied or unoccupied.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller continuously updates model parameters based on measured thermal responses and environmental conditions, enabling adaptation to different operating points. This parameter adaptation allows the system to maintain effective temperature regulation across diverse scenarios without requiring manual retuning.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If conventional control systems are used, then the system can provide basic thermal control, but it cannot provide personalized thermal comfort

Engineering Contradiction:
Improvethermal controlVSAvoidpersonalization capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system implements distributed sensors and actuators that enable zone-level or even room-level thermal control, allowing personalized comfort settings for different occupied spaces. The dynamic model captures local thermal characteristics, enabling tailored control strategies for each zone rather than uniform building-wide control.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The adaptive controller dynamically adjusts control parameters based on real-time occupancy detection and environmental conditions, enabling personalized thermal comfort for different users and situations. This dynamic adaptation allows the system to respond to individual preferences and changing occupancy patterns.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS7966104B2Apparatus and method for the control of the indoor thermal environment having feed forward and feedback control using adaptive reference models
Publication Date: 2011.06.21 SIEMENS CORP
  • US7966104B2 patent drawing
  • US7966104B2 patent drawing
  • US7966104B2 patent drawing

AI summary

A controller for controlling thermal sources affecting an air temperature in a space subjected to thermal variables, including a sensor network measuring the thermal variables; a feed forward controller generating a feed forward control signal based on an adaptive model including a model of the space and a model of the thermal sources, wherein the models are formed utilizing data from the sensor network; a feedback controller generating a feedback control signal based on a difference between an output of the feed forward controller and output from the space; and a combiner combining the feed forward and feedback control signals to produce a control signal for controlling the thermal sources to control the air temperatures of the space.