HFO Working Medium Acid Detection in Heat Cycle Systems

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Solution Overview

Problem

Hydrofluoroolefin (HFO) working media in heat cycle systems are prone to decomposition under compression and heating, generating acidic products that can adversely affect system reliability, necessitating effective detection methods.

Innovation Solution

Incorporating a working medium containing HFO, such as HFO-1123, with optional components like HFC-32 and HFO-1234yf, and employing an acid detection system with a sight glass in the discharge pipe to monitor for decomposition products like hydrogen fluoride, allowing for appropriate detection of medium decomposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If HFO working medium is used to reduce global warming potential, then environmental compatibility is improved, but decomposition occurs under compression and heating conditions

Engineering Contradiction:
Improveglobal warming potentialVSAvoidstability under compression and heating
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies preliminary action by installing an acid detection means before decomposition products can cause significant harm. The sight glass and detection system are positioned in the discharge pipe to detect acid formation early, allowing preventive maintenance before reliability is compromised. This proactive detection resolves the contradiction by enabling early intervention while using environmentally friendly HFO refrigerants.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If HFO working medium is used to reduce ozone layer impact, then environmental compatibility is improved, but decomposition products such as acid are generated

Engineering Contradiction:
Improveozone layer influenceVSAvoiddecomposition products
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback by using the acid detection means to continuously monitor the working medium for decomposition products. The sight glass provides visual feedback about acid formation, and the detection system sends signals when decomposition occurs. This feedback mechanism allows operators to adjust system conditions or maintain the system before decomposition products accumulate to harmful levels, resolving the contradiction between using eco-friendly HFO and preventing its decomposition.

Inventive Principle:
Principle #23Feedback

3Reliability

If acid detection means is installed to detect decomposition, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvedetection capabilityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies this principle by using a simple, inexpensive sight glass as the primary detection means. The sight glass is a basic optical component that can be easily replaced if needed, rather than using complex electronic sensors or analysis systems. This simple, low-cost approach provides reliable acid detection without significantly increasing system complexity, resolving the contradiction between detection capability and system simplicity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 reliable detection of HFO decomposition in heat cycle systems, maintaining system integrity and efficiency by identifying acid generation, thus preventing corrosion and performance degradation.

Implementation Method 1

an acid detection means 40 which detects acid generated by decomposition of the working medium in the discharge pipe 21

Methodology Applied
Scientific EffectOptical observation:

Data Source

PatentEP3505851B1Use of a working medium containing hydrofluoroolefin (HFO) as a working medium in a heat cycle system
Publication Date: 2023.10.25 AGC INC
  • EP3505851B1 patent drawingFigure 1
  • EP3505851B1 patent drawingFigure 2~3
  • EP3505851B1 patent drawingFigure 4~6

AI summary

A heat cycle system is a heat cycle system (1) using a working medium containing hydrofluoroolefin (HFO) that has a double bond in a molecule structure, the heat cycle system (1) having a compressor (10), a high-pressure side heat exchanger (12), a low-pressure side heat exchanger (14), an expansion mechanism (13), and an acid detection means (40) which is disposed in a discharge pipe (21) connecting the compressor (10) and the high-pressure side heat exchanger (12) and which detects acid generated by decomposition of the working medium in a heat cycle.