Outdoor unit and refrigeration cycle device

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Solution Overview

Problem

In refrigeration cycle apparatuses, the high-pressure-side pressure on the outlet side of the compressor increases due to load fluctuations, leading to unsuppressed pressure increases, particularly in high load states, which can cause inefficiencies and operational challenges.

Innovation Solution

An outdoor unit with an injection circuit that includes an expansion valve, a receiver, and a flow control valve, where the controller adjusts the degree of opening of these valves to increase the gas-flow ratio of refrigerant returned to the compressor when pressure exceeds a threshold, reducing the liquid refrigerant stored in the receiver and circulating refrigerant amount.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple release capillary tubes are provided on the outlet side of the absorber tank to enable stepwise refrigerant release according to load fluctuations, then the refrigerant release amount can be adjusted in steps, but the high-pressure-side pressure increase cannot be suppressed in high load states

Engineering Contradiction:
Improverefrigerant release adjustmentVSAvoidhigh-pressure-side pressure
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The patent applies dynamics by making the refrigerant release mechanism continuously adjustable rather than fixed in steps. The electronic expansion valve replaces the fixed capillary tubes, allowing the release amount to be dynamically adjusted according to real-time pressure conditions and load requirements, thus resolving the contradiction between adaptability and pressure control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the key parameter of refrigerant release from discrete stepwise values to continuous adjustable values. By using an electronic expansion valve with variable opening degrees, the system can precisely control the refrigerant release amount to match varying load conditions while maintaining pressure within acceptable ranges

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the degree of opening of the release valve is increased in high load state to increase liquid refrigerant flow, then the refrigerant release amount increases, but the pressure on the outlet side of the compressor increases

Engineering Contradiction:
Improveliquid refrigerant flow amountVSAvoidcompressor outlet pressure
Core Design Contradiction:
Quantity of substanceVSStress or pressure

Solution Approach 1:

The patent implements feedback control by using a pressure sensor to detect the high-pressure-side pressure and a controller to adjust the electronic expansion valve opening degree based on the detected pressure. This closed-loop feedback mechanism ensures that the refrigerant release amount is automatically adjusted to maintain pressure within acceptable ranges while meeting cooling demands

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the refrigerant release amount in real-time based on actual operating conditions. The electronic expansion valve can be precisely controlled to release the exact amount of refrigerant needed, avoiding both excessive release (which would cause pressure drops) and insufficient release (which would cause pressure buildup)

Inventive Principle:
Principle #15Dynamics

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

Effectively suppresses the increase in pressure on the compressor outlet side by increasing the gas-flow ratio and reducing the liquid refrigerant circulation, enhancing the efficiency of the refrigeration cycle apparatus.

Implementation Method 1

an expansion valve (70) decompresses the refrigerant (81)

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Implementation Method 2

a condenser (20) configured to condense the refrigerant output from the compressor

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4030115B1Outdoor unit and refrigeration cycle device
Publication Date: 2023.10.25 MITSUBISHI ELECTRIC CORP
  • EP4030115B1 patent drawingFigure 1
  • EP4030115B1 patent drawingFigure 2~3
  • EP4030115B1 patent drawingFigure 4~5

AI summary

An injection circuit is configured to return part of refrigerant on an outlet side of a condenser (20) to a compressor (10) without passing through a load unit (3). An expansion valve (70) is provided on a pipe branched from the outlet side of the condenser (20). A receiver (71) is provided on a low-pressure side of the expansion valve (70) and configured to accumulate refrigerant in a gas-liquid two-phase state. A flow control valve (72) is provided downstream of the receiver (71). When a pressure of the refrigerant output from the compressor (10) exceeds a threshold value, a controller (100) increases a degree of opening of the expansion valve (70) and increases a gas-flow ratio of refrigerant returned from the receiver (71) to the compressor (10) by adjusting a degree of opening of the flow control valve (72), more than when the pressure is equal to or less than the threshold value.