HVAC Refrigerant Leak Detection with Damper-Guided Multi-Space Sensing

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Solution Overview

Problem

HVAC systems using flammable refrigerants pose a safety risk due to the potential for leaks and subsequent fires, especially in enclosed spaces, as existing detection methods are inadequate for real-time monitoring and response.

Innovation Solution

An HVAC system with a flammable-component detector and processing unit that monitors refrigerant levels, activates a damper to control airflow, and uses a ventilator to dilute leaks, providing alerts and responsive actions to prevent flammable refrigerant accumulation and ensure user safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flammable refrigerants are used to reduce global warming potential, then environmental performance is improved, but safety risk increases due to fire hazard from potential leaks

Engineering Contradiction:
Improveenvironmental performanceVSAvoidfire hazard
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary detection by continuously monitoring refrigerant levels and leak conditions before a fire hazard can develop. The flammable-component detector and processing unit identify leak conditions in advance, allowing the system to activate the damper and ventilator proactively to prevent refrigerant accumulation to dangerous levels.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The damper and ventilator act as intermediary components between the leak detection and the potential fire hazard. When a leak is detected, the damper closes to isolate the refrigerant, and the ventilator activates to dilute and remove the refrigerant from the equipment space, serving as a protective intermediary that prevents the harmful effect from materializing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If real-time leak detection and response systems are implemented to improve safety, then safety risk is reduced, but device complexity increases

Engineering Contradiction:
Improvefire hazardVSAvoiddetection system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The processing unit serves multiple functions: it receives operational status signals from the blower, controls the damper based on blower status and leak detection, monitors the flammable-component detector, and activates alerts. This multi-functionality consolidates what could be multiple separate control systems into a single unit, reducing overall system complexity while maintaining comprehensive safety monitoring and response capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges the detection function (flammable-component detector), control function (damper and ventilator control), and alert function into an integrated system managed by a single processing unit. This consolidation simplifies the architecture compared to having separate independent systems for each function, making the overall system more manageable despite the added safety capabilities.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the damper is opened to allow air flow for detection purposes, then leak detection accuracy is improved, but refrigerant accumulation risk increases

Engineering Contradiction:
Improveleak detection accuracyVSAvoidrefrigerant accumulation
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The damper position is dynamically adjusted based on real-time conditions. The processing unit opens the damper when the blower is not operating to enable the flammable-component detector to sample air and detect leaks accurately. When the blower is operating or when a leak is detected, the damper closes to prevent refrigerant accumulation. This dynamic adjustment allows the system to optimize both detection accuracy and safety according to current operational conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the blower operational status to control damper position. The processing unit receives operational status signals from the blower and adjusts the damper accordingly. Additionally, feedback from the flammable-component detector about detected refrigerant levels triggers damper closure to prevent accumulation, creating a closed-loop control system that balances detection needs with safety requirements.

Inventive Principle:
Principle #23Feedback

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

The system effectively detects refrigerant leaks, prevents accumulation, and ensures user safety by activating the blower and ventilator to dilute refrigerant, providing timely alerts and reducing the risk of fires in HVAC systems using flammable refrigerants.

Implementation Method 1

a flammable-component detector disposed within the equipment space proximate the access port

Methodology Applied
Scientific EffectFlammable component detection:

Implementation Method 2

uses a ventilator to dilute leaks

Methodology Applied
Scientific EffectDilution:

Implementation Method 3

The cooling aspect of the HVAC system utilizes a working fluid, or refrigerant, that cycles through various phases to realize cooling

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2955454B1HVAC systems and methods with refrigerant leak detection
Publication Date: 2020.02.12 LENNOX IND INC
  • EP2955454B1 patent drawingFigure 1
  • EP2955454B1 patent drawingFigure 2
  • EP2955454B1 patent drawingFigure 3~6

AI summary

Systems and methods are disclosed that involve detecting a flammable refrigerant associated with a heating, ventilating, and air conditioning (HVAC) system. In one instance a damper covers an access port allowing a single sensor to monitor at least two separate spaces. In another instance, a multi-probe sensor allows a single sensor to monitor at least two separate spaces. Other systems and methods are presented.