Refrigeration cycle device

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Solution Overview

Problem

The refrigeration cycle apparatus faces instability during low-outdoor-temperature cooling operations due to insufficient liquid refrigerant, leading to cavitation in the liquid pump, which can cause system failure.

Innovation Solution

The apparatus employs a control device to manage the compressor and liquid pump, initiating a vapor compression cycle before turning on the liquid pump, thereby increasing the generation rate of liquid refrigerant in the condenser and reducing cavitation risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a liquid pump cycle is used for low-outdoor-temperature cooling operation, then power consumption is reduced compared to vapor compression cycle, but insufficient liquid refrigerant causes cavitation in the liquid pump leading to system failure

Engineering Contradiction:
Improvepower consumptionVSAvoidstability of low-outdoor-temperature cooling operation
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The control device performs preliminary action by operating the compressor in vapor compression cycle before switching to liquid pump cycle, thereby pre-generating sufficient liquid refrigerant in the condenser. This preliminary liquid refrigerant generation prevents cavitation when the liquid pump starts operation, resolving the contradiction between energy efficiency and system reliability.

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If the liquid pump operates immediately to achieve low power consumption, then energy efficiency improves, but the amount of liquid refrigerant is insufficient causing the liquid pump to suction wet vapor and cavitation occurs

Engineering Contradiction:
Improvepower consumptionVSAvoidamount of liquid refrigerant
Core Design Contradiction:
Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The system performs preliminary action by running the compressor first to generate adequate liquid refrigerant inventory in the condenser before activating the liquid pump. This ensures sufficient liquid refrigerant quantity is available when the pump operates, preventing wet vapor suction and cavitation while maintaining energy efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device implements periodic action by alternating between vapor compression cycle (for liquid refrigerant generation) and liquid pump cycle (for efficient cooling operation). This periodic switching ensures the system maintains adequate liquid refrigerant levels while achieving low power consumption during the liquid pump operation phases.

Inventive Principle:
Principle #19Periodic action

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 approach enhances the stability of low-outdoor-temperature cooling operations by ensuring sufficient liquid refrigerant is available, preventing cavitation and maintaining system functionality.

Implementation Method 1

a rate of generation of liquid refrigerant in a condenser increases

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

liquid refrigerant can evaporate in an evaporator in a room by making use of a difference between an indoor temperature and an outdoor temperature

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

The compressor is configured to compress the refrigerant from the evaporator and output the refrigerant to the condenser

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

The pump is configured to compress the refrigerant from the condenser and output the refrigerant to the evaporator

Methodology Applied
Scientific EffectPumping: Pump

Data Source

PatentEP3557151B1Refrigeration cycle device
Publication Date: 2020.09.16 MITSUBISHI ELECTRIC CORP
  • EP3557151B1 patent drawingFigure 1~2
  • EP3557151B1 patent drawingFigure 3~4
  • EP3557151B1 patent drawingFigure 5~6

AI summary

A refrigeration cycle apparatus according to the present invention performs cooling by circulation of refrigerant. The refrigeration cycle apparatus includes an evaporator, a condenser, a pump (6), a compressor (1), and a control device. The evaporator is arranged in a first space. The condenser is arranged in a second space. The pump (6) is configured to compress refrigerant from the condenser and output the refrigerant to the evaporator. The compressor (1) is configured to compress refrigerant from the evaporator and output the refrigerant to the condenser. The control device is configured to control the pump (6) and the compressor (1) to cool the first space. The control device is configured to turn on the pump (6) after turn-on of the compressor (1) while a temperature of the first space is higher than a temperature of the second space.