Indoor unit and heat pump

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Solution Overview

Problem

Heat pumps face challenges in preventing refrigerant leakage into indoor spaces, which can lead to flammable concentrations and increased safety risks, particularly with flammable refrigerants, and existing solutions like double-walled heat exchangers and gas-liquid separators are costly and complex.

Innovation Solution

An indoor unit configuration with a container that includes a gas-liquid separator, a gas purge valve, and a duct system that directs any leaked refrigerant to the outdoors, combined with a pressure relief valve and refrigerant leakage detector, to prevent refrigerant accumulation and flow into indoor spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a double-walled plate heat exchanger is used to prevent refrigerant leakage, then refrigerant leakage prevention is improved, but manufacturing cost increases

Engineering Contradiction:
Improverefrigerant leakage preventionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the indoor unit into a sealed container (casing) that isolates the heat exchanger and refrigerant circuit from the indoor space. This segmentation approach prevents refrigerant leakage into the indoor environment by creating a separate enclosed zone, offering a cost-effective alternative to expensive double-walled heat exchangers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a sealed container as an intermediary structure between the refrigerant circuit and the indoor space. This intermediary casing with controlled openings and ventilation ducts acts as a barrier that prevents direct refrigerant leakage into the indoor environment, replacing the need for complex double-walled heat exchanger structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a gas-liquid separator with gas purge valve is arranged outside the box in the indoor space, then refrigerant separation function is improved, but refrigerant leakage risk increases due to additional piping connections

Engineering Contradiction:
Improverefrigerant separation functionVSAvoidrefrigerant leakage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines the gas-liquid separator and gas purge valve inside the sealed container along with the heat exchanger. This merging of components eliminates the need for external piping connections that would create additional leakage points, while maintaining the refrigerant separation function within the protected indoor-unit boundary.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the gas-liquid separator and gas purge valve from the outdoor configuration and places them inside the sealed container. This extraction from the outdoor space and integration into the indoor unit's sealed environment eliminates the need for vulnerable external piping connections while preserving the refrigerant separation functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If the compressor is placed inside the box with leaked refrigerant, then space utilization is improved, but inflammation risk increases due to proximity of ignition source to refrigerant

Engineering Contradiction:
Improvespace utilizationVSAvoidinflammation risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potential harm of having the compressor inside the container by implementing a controlled ventilation system. The ventilation duct with opening to the outdoor space creates a continuous airflow that prevents refrigerant accumulation around the compressor, transforming the risky configuration into a safe one by using ventilation to dissipate potential flammable concentrations.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the operational parameters of the ventilation system by controlling the opening/closing of the ventilation duct based on operational conditions. This dynamic parameter adjustment ensures that the compressor operates in a controlled atmosphere, preventing refrigerant accumulation to flammable levels while maintaining space efficiency.

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

This configuration effectively prevents refrigerant leakage into indoor spaces, enhances safety, and reduces costs by simplifying the structure and eliminating the need for additional sealing and ventilation systems.

Implementation Method 1

a first duct provided at the container, the first duct communicating an inside of the container with an outdoor space for air exchange between the inside of the container and the outdoor space

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

a gas-liquid separator provided in the heat medium circuit, the gas-liquid separator comprising a gas purge valve to release refrigerant

Methodology Applied
Scientific EffectGas-liquid separation:

Implementation Method 3

an intermediate heat exchanger to exchange heat between a refrigerant and the heat medium

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4467900A1Indoor unit and heat pump
Publication Date: 2024.11.27 DAIKIN EURO
  • EP4467900A1 patent drawingFigure 1
  • EP4467900A1 patent drawingFigure 2~3
  • EP4467900A1 patent drawingFigure 4~5

AI summary

The present invention relates to an indoor unit and a heat pump. An indoor unit for a heat pump installed inside of a building, comprising a part of a heat medium circuit for circulating a heat medium, an intermediate heat exchanger to exchange heat between a refrigerant and the heat medium, a gas-liquid separator provided in the heat medium circuit, the gas-liquid separator comprising a gas purge valve to release refrigerant, a container accommodating the intermediate heat exchanger, the gas purge valve, and the gas-liquid separator, and a first duct provided at the container, the first duct communicating an inside of the container with an outdoor space for air exchange between the inside of the container and the outdoor space, wherein the outdoor space is outside of the building