Refrigeration cycle device

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing refrigeration cycle devices with suction injection pipes and subcooling heat exchangers face challenges in increasing the evaporation capacity of the use-side heat exchanger, especially under varying operating conditions such as outside air temperature.

Innovation Solution

The introduction of a sub-refrigerant circuit and a control unit that switches between the cooling actions of the subcooling heat exchanger and the sub-refrigerant circuit, using the suction injection pipe and subcooling heat exchanger to cool the refrigerant flowing between the expansion mechanism and the use-side heat exchanger, and the sub-refrigerant circuit to further reduce the enthalpy of the refrigerant.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the suction injection pipe and subcooling heat exchanger are provided to cool the refrigerant, then the evaporation capacity of the use-side heat exchanger is increased, but the effect is insufficient under certain operating conditions such as high outside air temperature

Engineering Contradiction:

Improveevaporation capacity of the use-side heat exchangerVSAvoidstability of evaporation capacity under varying operating conditions

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention divides the single refrigerant circuit into two separate circuits: a main refrigerant circuit and a sub-refrigerant circuit. The main circuit handles primary cooling through the subcooling heat exchanger, while the sub-circuit provides additional cooling capacity through the sub-use-side heat exchanger when needed. This segmentation allows independent control of each circuit's cooling contribution, enabling the system to adapt to varying operating conditions and maintain stable evaporation capacity regardless of outside air temperature.

Inventive Principle:

Principle #1Segmentation

2Productivity

If only the subcooling heat exchanger is used to cool the refrigerant, then the system structure remains simple, but the evaporation capacity cannot be sufficiently increased under all operating conditions

Engineering Contradiction:

Improveevaporation capacity of the use-side heat exchangerVSAvoidrefrigerant circuit structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention incorporates a control unit that dynamically switches between different cooling modes based on operating conditions. The control unit can operate the sub-compressor independently or in coordination with the main compressor, and can switch between using only the subcooling heat exchanger, only the sub-use-side heat exchanger, or both together. This dynamic control allows the system to optimize its complexity level according to the required evaporation capacity, maintaining simplicity when sufficient cooling is achieved while providing enhanced capability when needed.

Inventive Principle:

Principle #15Dynamics

3Productivity

If the sub-refrigerant circuit is added to further reduce refrigerant enthalpy, then the evaporation capacity is increased regardless of operating conditions, but the system complexity and energy consumption increase

Engineering Contradiction:

Improveevaporation capacity of the use-side heat exchangerVSAvoidenergy consumption of the refrigeration cycle device

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The invention incorporates a control unit that dynamically switches between different cooling modes based on operating conditions. The control unit can operate the sub-compressor independently or in coordination with the main compressor, and can switch between using only the subcooling heat exchanger, only the sub-use-side heat exchanger, or both together. This dynamic control allows the system to optimize its energy consumption by activating the sub-refrigerant circuit only when additional cooling capacity is required, rather than operating continuously at full complexity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the refrigeration system by introducing a second refrigerant circuit with its own compressor and heat exchanger. The control unit adjusts the operating parameters (compressor speed, heat exchanger activation) based on the required cooling load and outside air temperature, optimizing the balance between evaporation capacity enhancement and energy consumption. The system can operate in multiple parameter states ranging from single-circuit mode to dual-circuit mode.

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 solution effectively increases the evaporation capacity of the use-side heat exchanger regardless of operating conditions, optimizing the coefficient of performance of the refrigeration cycle device by adjusting the cooling actions based on temperature and subcooling degrees.

Implementation Method 1

the subcooling heat exchanger cooling a refrigerant that flows between the expansion mechanism and the use-side heat exchanger by heat exchange with a refrigerant that flows in the suction injection pipe

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the suction injection pipe causing a refrigerant that flows between the heat-source-side heat exchanger and the use-side heat exchanger to branch off and to be sent to a suction side of the compressor

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

an expansion mechanism that is configured to decompress the main refrigerant that flows between the main heat-source-side heat exchanger and the main use-side heat exchanger

Methodology Applied

Scientific EffectDecompression: Depressurisation

Implementation Method 4

The main compressor is a compressor that is configured to compress a main refrigerant

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 5

The sub-compressor is a compressor that is configured to compress the sub-refrigerant

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 6

The main heat-source-side heat exchanger is a heat exchanger that is configured to function as a heat dissipater (a radiator) of the main refrigerant

Methodology Applied

Scientific EffectHeat dissipation: Heat Sink

Implementation Method 7

The main use-side heat exchanger is a heat exchanger that is configured to function as an evaporator of the main refrigerant

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3862651B1Refrigeration cycle device

Publication Date: 2022.10.26 DAIKIN INDUSTRIES LTD

Figure 1
Figure 2
Figure 3

AI summary

In order to increase the evaporation capacity of a use-side heat exchanger regardless of operating conditions, a suction injection pipe (61) and a subcooling heat exchanger (62) are provided at a main refrigerant circuit (20) in which a main refrigerant circulates. Further, a sub-refrigerant circuit (80) that differs from the main refrigerant circuit (20) and in which a sub-refrigerant circulates is provided. A control unit (9) performs control for switching between a cooling action of the subcooling heat-exchanger that cools the main refrigerant that is sent to a main use-side heat exchanger (72a, 72b) by using the suction injection pipe (61) and the subcooling heat exchanger (62), and a cooling action of the sub-refrigerant-circuit that cools the main refrigerant that is sent to the main use-side heat exchanger (72a, 72b) by using the sub-refrigerant circuit 80.