Refrigeration cycle apparatus

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Solution Overview

Problem

Existing refrigeration cycle apparatuses face challenges in controlling fluctuations in the heating capacity of a use side heat exchanger when the injection flow rate of refrigerant into the compressor is changed, leading to inefficiencies and reliability issues.

Innovation Solution

A refrigeration cycle apparatus with a main refrigerant circuit and a bypass refrigerant circuit, where the bypass circuit includes a second expansion valve and communicates with the compressor's injection port. A controller adjusts the compressor's operating frequency and the second expansion valve's opening degree to manage the injection flow rate and stabilize the heating capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the injection flow rate of refrigerant into the compressor is changed, then the heating capacity of the use side heat exchanger can be adjusted, but fluctuations in heating capacity occur leading to inefficiency

Engineering Contradiction:

Improveheating capacity adjustmentVSAvoidheating capacity stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The controller monitors the injection flow rate through the second expansion valve and automatically adjusts the compressor operating frequency in response. This closed-loop feedback mechanism compensates for heating capacity fluctuations caused by injection flow rate changes, maintaining stable and efficient operation of the use side heat exchanger

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the compressor operating frequency based on the opening degree of the second expansion valve. This dynamic coordination between the expansion valve and compressor frequency ensures that heating capacity remains stable even as injection flow rate varies, preventing inefficiency

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the second expansion valve opening degree is adjusted to control injection flow rate, then refrigerant injection can be managed, but heating capacity fluctuations occur

Engineering Contradiction:

Improveinjection flow rate controlVSAvoidheating capacity stability

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The controller uses feedback from the second expansion valve opening degree to automatically adjust the compressor operating frequency. This feedback mechanism ensures that heating capacity remains stable even when the injection flow rate is adjusted through the expansion valve, maintaining productivity while preserving ease of operation

Inventive Principle:

Principle #23Feedback

3Reliability

If compressor operating frequency is changed to compensate for injection flow rate changes, then heating capacity stability can be maintained, but system complexity increases

Engineering Contradiction:

Improveheating capacity stabilityVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The controller implements a feedback mechanism that automatically adjusts compressor operating frequency based on the second expansion valve opening degree. This automated feedback control maintains heating capacity stability without requiring complex manual intervention or additional hardware components, managing system complexity effectively

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The controller performs multiple functions: it manages the first expansion valve, the second expansion valve, and the compressor operating frequency all through a single control unit. This multi-functionality reduces the need for separate control mechanisms, managing system complexity while maintaining heating capacity stability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 allows for precise control of the heating capacity of the use side heat exchanger, mitigating the effects of changes in refrigerant injection flow rate and enhancing the overall efficiency and reliability of the refrigeration cycle.

Implementation Method 1

a compressor (11) having an injection port (11a) communicating with a compression chamber

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

a first expansion valve (14)... a second expansion valve (21)

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Implementation Method 3

a use side heat exchanger (12)... a heat source side heat exchanger (15)

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4495506A1Refrigeration cycle apparatus

Publication Date: 2025.01.22 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

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AI summary

A refrigeration cycle apparatus (1) includes a main refrigerant circuit (10) through which a refrigerant circulates, the main refrigerant circuit (10) including a compressor (11), a use side heat exchanger (12), a first expansion valve (14), and a heat source side heat exchanger (15) connected in order, a bypass refrigerant circuit (20) branching off from the main refrigerant circuit (10), the bypass refrigerant circuit (20) communicating with the injection port (11a) of the compressor (11), the bypass refrigerant circuit (20) including a second expansion valve (21) and the use side heat exchanger (12) connected in order from the main refrigerant circuit side, and a controller (50), in which the controller (50) executes compressor operation control to change the operating frequency of the compressor (11) in accordance with the opening degree of the second expansion valve (21).