Cooling/heating switching unit

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Solution Overview

Problem

Existing refrigerant leak detection methods in multi-system air conditioners for simultaneous cooling and heating are complicated and prone to inaccuracies due to temperature variations, especially in the cooling/heating switching unit with numerous pipe connections, making reliable detection challenging.

Innovation Solution

A cooling/heating switching unit equipped with refrigerant leak detection sensors installed strategically near potential leak points, such as fittings and pipe joints, to accurately detect refrigerant leaks by utilizing sensors that can distinguish refrigerant flow from air, with a centralized management system for notification and identification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature sensors are installed in indoor units to detect refrigerant leaks, then leak detection capability is provided, but the detection flow becomes complicated and requires separate processing for each indoor unit

Engineering Contradiction:
Improverefrigerant leak detection capabilityVSAvoiddetection flow complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent consolidates refrigerant leak detection for multiple indoor units into a single centralized detection system located in the outdoor unit. Instead of each indoor unit having independent detection capabilities, the system merges all detection functions into one location, simplifying the overall detection flow while maintaining comprehensive monitoring coverage across all indoor units.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If temperature sensors are used to detect refrigerant leaks, then leak detection is possible, but temperature variations from seasons and refrigerant circulation cause inaccurate measurements

Engineering Contradiction:
Improverefrigerant leak detection accuracyVSAvoidtemperature measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent extracts the refrigerant leak detection function from temperature-based indirect detection and implements it through direct refrigerant detection using a specialized sensor. This removes the confounding influence of temperature variations caused by seasonal changes and refrigerant circulation, allowing for accurate leak detection independent of thermal conditions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/thermal-based temperature sensor detection method with a chemical/optical-based direct refrigerant detection sensor. This substitution eliminates the reliance on temperature measurements that are susceptible to environmental and operational variations, providing more precise and reliable leak detection.

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

3Reliability

If multiple temperature sensors are installed in a multi-system air conditioner with simultaneous cooling and heating, then each indoor unit can be monitored, but the system complexity and detection flow become excessively complicated

Engineering Contradiction:
Improvesimultaneous cooling and heating monitoringVSAvoiddetection flow complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the detection functions for multiple indoor units operating in simultaneous cooling and heating modes into a single centralized detection system in the outdoor unit. This consolidation allows the system to monitor all indoor units through one unified detection flow, dramatically reducing complexity while maintaining the ability to detect leaks in any individual unit.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables simple and reliable detection of refrigerant leaks in the cooling/heating switching unit, reducing the complexity of the detection process and improving accuracy, even in environments with varying temperatures, thereby ensuring timely action and minimizing global warming impacts.

Implementation Method 1

utilizing sensors that can distinguish refrigerant flow from air

Methodology Applied
Scientific EffectDensity difference: Density Gradient

Data Source

PatentEP3270069B1Cooling/heating switching unit
Publication Date: 2020.06.03 HITACHI JOHNSON CONTROLS AIR CONDITIONING INC
  • EP3270069B1 patent drawingFigure 1
  • EP3270069B1 patent drawingFigure 2A~2B
  • EP3270069B1 patent drawingFigure 3

AI summary

A cooling/heating switching unit is provided that is capable of simply and reliably detecting leak of refrigerant. The cooling/heating switching unit includes: a fitting 37 and a fitting 38 that have a high/low-pressure gas main pipe 24 and a low-pressure gas main pipe 27 connected thereto, respectively, wherein the pipes 24, 27 are linked to an outdoor unit 10; a fitting 39 that has an indoor-unit connection pipe 28 connected thereto, wherein the pipe 28 is linked to an indoor unit 40; an expansion valve for high/low-pressure gas pipe 31, an expansion valve for low-pressure gas pipe 32, and expansion-valve driving sections 33 and 34 that selectively connect the fitting 37 or the fitting 38 with the fitting 39 via a refrigerant pipe to control a flow direction of refrigerant; a housing 50 that houses the refrigerant pipe; a heat insulating material that fills inside of the housing 50 to insulate the refrigerant pipe arranged inside of the housing 50 from heat; and a refrigerant leak detection sensor 81 that is installed outside of the housing 50 to detect leaked refrigerant.