Optimized HVAC control using domain knowledge combined with deep reinforcement learning (DRL)

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Solution Overview

Problem

Existing HVAC control systems face challenges in optimizing energy consumption and occupant comfort due to conflicts in rule-based systems and the lengthy exploration phase of machine learning-based approaches like DRL.

Innovation Solution

A method and system that combines domain knowledge with Deep Reinforcement Learning (DRL) using Expressive Decision Tables (EDT) to analyze HVAC parameters and resolve conflicts, thereby selecting optimal control actions that maximize cumulative rewards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If rule-based systems are used for HVAC control, then ease of implementation is improved, but energy optimization and conflict resolution capability deteriorate

Engineering Contradiction:
Improveease of implementationVSAvoidenergy optimization
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent introduces a conflict resolution module as an intermediary between the rule-based system and the HVAC controller. This module receives control actions from multiple conflicting rules, resolves their conflicts using prioritization strategies, and outputs a single optimized control action. This intermediary layer maintains the ease of rule-based implementation while adding sophisticated conflict resolution capability to improve energy optimization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If DRL-based approaches are used for HVAC control, then optimal control performance is improved, but learning duration and implementation complexity worsen

Engineering Contradiction:
Improvecontrol performanceVSAvoidlearning duration
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-training the DRL agent using synthetic data generated from building simulations before deploying it to real HVAC systems. This pre-training phase allows the agent to learn optimal control strategies in a virtual environment, significantly reducing the online learning duration required when the system is deployed to actual buildings. The pre-trained policy serves as a good initial starting point for fine-tuning with real-world data.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If multiple rules are applied in rule-based systems, then control coverage is improved, but conflict resolution capability worsens

Engineering Contradiction:
Improvecontrol coverageVSAvoidconflict resolution complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the conflict resolution process into distinct modular components: rule evaluation module, conflict detection module, prioritization module, and action selection module. Each module handles a specific aspect of conflict resolution independently. This segmentation allows the system to manage multiple rules effectively while keeping the complexity of conflict resolution tractable through modular design, where each segment can be developed and tested independently.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS12222122B2Optimized HVAC control using domain knowledge combined with deep reinforcement learning (DRL)
Publication Date: 2025.02.11 TATA CONSULTANCY SERVICES LTD
  • US12222122B2 patent drawing
  • US12222122B2 patent drawing
  • US12222122B2 patent drawing

AI summary

HVAC control system's supervisory control is crucial for energy-efficient thermal comfort in buildings. The control logic is usually specified as ‘if-then-that-else’ rules that capture the domain expertise of HVAC operators, but they often have conflict that may lead to sub-optimal HVAC performance. Embodiments of the present disclosure provide a method and system for optimized Heating, ventilation, and air-conditioning (HVAC) control using domain knowledge combined with Deep Reinforcement Learning (DRL). The system disclosed utilizes Deep Reinforcement Learning (DRL) for conflict resolution in a HVAC control in combination with domain knowledge in form of control logic. The domain knowledge is predefined in an Expressive Decision Tables (EDT) engine via a formal requirement specifier consumable by the EDT engine to capture domain knowledge of a building for the HVAC control.