HVAC Model Identification Under Comfort-Neutral Testing

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Solution Overview

Problem

The setup of multi-input-multi-output (MIMO) control systems for HVAC systems is complex and requires skilled control engineers, leading to high costs and potential disruptions in building comfort during testing, as it involves setting relations between manipulated and controlled variables and a cost objective function.

Innovation Solution

A method that automatically identifies a steady-state HVAC system model and cost objective model by pairing manipulated and controlled variables, perturbing a variable to maintain comfort conditions, and deriving a model without expert intervention, using proportional integral control and look-up tables to ensure comfort is maintained during system exploration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional step-testing method is used for MIMO controller setup, then control model identification can be achieved, but building comfort is disrupted and high expert costs are incurred

Engineering Contradiction:
Improvecontrol model identification accuracyVSAvoidbuilding comfort disruption
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system preemptively counteracts potential comfort disruptions by implementing comfort constraints before testing begins. The comfort-safe step testing methodology pre-defines acceptable ranges for controlled variables, ensuring that any perturbations applied during identification maintain inhabitant comfort throughout the process.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The system continuously monitors controlled variables during the identification process and uses feedback mechanisms to adjust perturbations. By measuring actual system responses and comparing them against comfort thresholds, the controller adapts its testing strategy in real-time to prevent comfort violations while still gathering necessary identification data.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If traditional step-testing method is used for MIMO controller setup, then control model identification can be achieved, but expert control engineers are required leading to high costs

Engineering Contradiction:
Improvecontrol model identification accuracyVSAvoidsetup complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-identification by automatically selecting perturbations, executing tests, collecting data, and generating the control model without human intervention. The automated methodology includes built-in logic for variable pairing, perturbation selection, and model derivation, enabling the HVAC system to configure its own MIMO controller through comfort-safe step testing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system prepares all necessary identification parameters, variable pairings, and comfort constraints in advance before actual testing begins. This preliminary configuration includes defining the cost objective function, setting measurement thresholds, and pre-planning the perturbation sequence, which eliminates the need for expert engineers during the actual identification process.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If MIMO control is implemented, then energy optimal control can be achieved, but controller setup becomes significantly more difficult

Engineering Contradiction:
Improveenergy optimizationVSAvoidcontroller setup ease
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The system replaces manual expert configuration with an automated identification process. Instead of requiring control engineers to manually pair variables and tune parameters, the system uses automated step testing with computational algorithms to derive the control model and configure the MIMO controller, substituting mechanical expert knowledge with automated computational methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system systematically varies operating parameters during the identification process to map system behavior across different conditions. By changing manipulated variables within comfort constraints and measuring resulting controlled variable responses, the system builds a comprehensive control model that captures energy optimization opportunities without requiring expert parameter tuning.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables a plug-and-play, comfort-safe setup of multivariable controllers, reducing the need for expert control engineers and minimizing disruptions, allowing for cost-optimal control of HVAC systems without compromising inhabitant comfort.

Implementation Method 1

controlling the HVAC system to maintain controlled variables in a comfort range

Methodology Applied
Scientific EffectProportional integral control: Feedback

Data Source

PatentUS9970673B2Model identification using comfort neutral testing
Publication Date: 2018.05.15 RESIDEO LLC
  • US9970673B2 patent drawing
  • US9970673B2 patent drawing
  • US9970673B2 patent drawing

AI summary

A method includes pairing manipulated variables and controlled variables in an HVAC system, perturbing a variable, controlling the HVAC system to maintain controlled variables in a comfort range, determining a state of the system, and deriving a model from the state of the system.