Refrigeration cycle device

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Solution Overview

Problem

Refrigeration cycle apparatuses with local pipes experience increased pressure loss and noise due to two-phase refrigerant flow, which affects efficiency and even refrigerant distribution across multiple indoor units.

Innovation Solution

Regulating the opening degree of the heat source-side pressure reducing device to ensure the refrigerant flows into the connection pipe as liquid refrigerant at a pressure less than the design pressure, using a variable-frequency compressor and electronic expansion valves to manage pressure and flow effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If two-phase refrigerant flows through the liquid pipe, then refrigerant cost is reduced, but pressure loss and noise in the liquid pipe increase

Engineering Contradiction:
Improverefrigerant costVSAvoidpressure loss
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent changes the physical state parameter of the refrigerant from two-phase to liquid phase before it enters the liquid pipe. By controlling the expansion valve to fully expand the refrigerant before the liquid pipe, the refrigerant remains in liquid state throughout the liquid pipe, eliminating the pressure loss and noise associated with two-phase flow while maintaining the refrigerant quantity reduction benefit

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If two-phase refrigerant flows through the liquid pipe, then refrigerant cost is reduced, but noise in the liquid pipe increases

Engineering Contradiction:
Improverefrigerant costVSAvoidnoise
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent changes the physical state parameter of the refrigerant from two-phase to liquid phase before it enters the liquid pipe. By controlling the expansion valve to fully expand the refrigerant before the liquid pipe, the refrigerant remains in liquid state throughout the liquid pipe, eliminating the noise associated with two-phase flow while maintaining the refrigerant quantity reduction benefit

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If liquid refrigerant flows into the connection pipe at high pressure, then flow control is simplified, but pressure loss and system efficiency decrease

Engineering Contradiction:
Improveflow control complexityVSAvoidpressure loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent segments the pressure reduction process into two distinct stages: first, the expansion valve reduces high pressure to a intermediate pressure while fully expanding the refrigerant into liquid state; second, the liquid pipe transports the liquid refrigerant at this intermediate pressure (below design pressure) to the indoor units. This segmentation allows each component to operate optimally without requiring high-pressure liquid flow control

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the pressure parameter of the liquid refrigerant before it enters the liquid pipe by using the expansion valve to reduce pressure to below the design pressure of the liquid pipe. This pressure reduction maintains liquid phase while enabling efficient transport through the liquid pipe without excessive pressure loss

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 reduces pressure loss and noise in the liquid pipe, improves refrigerant distribution, and decreases energy consumption, allowing for efficient operation even with multiple indoor units.

Implementation Method 1

regulating an opening degree of the heat source-side pressure reducing device, the refrigerant is caused to flow into the liquid pipe as liquid refrigerant at a pressure lower than a design pressure of the liquid pipe

Methodology Applied
Scientific EffectPressure reduction through valve opening regulation: Valve

Implementation Method 2

the refrigerant flowing from the outdoor unit to a liquid pipe is reduced in pressure by a flow control device and brought into a two-phase gas-liquid state

Methodology Applied
Scientific EffectPressure-induced phase change: Phase Change

Implementation Method 3

liquid refrigerant flows through the liquid pipe. Accordingly, pressure loss and noise in the liquid pipe increase

Methodology Applied
Scientific EffectLiquid flow through pipe: Pressure Drop

Data Source

PatentEP3312524B1Refrigeration cycle device
Publication Date: 2020.06.03 MITSUBISHI ELECTRIC CORP
  • EP3312524B1 patent drawingFigure 1~2
  • EP3312524B1 patent drawingFigure 3~4
  • EP3312524B1 patent drawingFigure 5~6

AI summary

Provided is a refrigeration cycle apparatus, including: a heat source-side unit; a load-side unit which is connected to the heat source-side unit by a first connection pipe arranged and a second connection pipe; and a controller, in which the first compressor, the first heat source-side heat exchanger, the first heat source-side pressure reducing device, the load-side pressure reducing device, and the load side heat exchanger are connected by a refrigerant pipe and form a first refrigeration cycle through which first refrigerant circulates, and in which, during cooling operation in which the load side heat exchanger functions as an evaporator, the controller regulates an opening degree of the first heat source-side pressure reducing device to cause the first refrigerant to flow into the first connection pipe as liquid refrigerant having a pressure less than a design pressure of the first connection pipe.