VRF Refrigerant Piping Layout for Simultaneous Cooling and Heating

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Solution Overview

Problem

Existing simultaneous cooling and heating type VRF systems require a complex pipe unit structure and increased installation area due to the need for switchable connections between outdoor and indoor units, complicating the refrigeration cycle and installation process.

Innovation Solution

A refrigeration cycle apparatus with two outdoor units and multiple indoor units, utilizing channel switching valves and pipe switching units to allow for switchable cooling and heating operations without the need for a dedicated pipe unit, enabling flexible operation and reduced installation complexity by alternating the roles of outdoor units between heat absorb and discharge cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If heat source units are connected in parallel with switchable connections to main high-pressure gas line and low-pressure gas line, then simultaneous cooling and heating operations can be performed, but the pipe unit structure becomes complicated and installation area increases

Engineering Contradiction:
Improvesimultaneous cooling and heating operation capabilityVSAvoidpipe unit structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent removes the complex pipe unit from the system by connecting each outdoor unit's gas-side refrigerant pipe directly to either the main high-pressure gas line or main low-pressure gas line without requiring a separate pipe unit. This extraction of the pipe unit eliminates structural complexity while maintaining the ability to perform simultaneous cooling and heating operations through direct line connections.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The main high-pressure gas line and main low-pressure gas line serve multiple functions by directly receiving refrigerant from multiple outdoor units without requiring a dedicated pipe unit. These lines universally handle refrigerant flow for both cooling and heating operations across different outdoor units, eliminating the need for specialized switching infrastructure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If heat source units are connected in parallel with switchable connections, then simultaneous cooling and heating operations can be performed, but installation area increases

Engineering Contradiction:
Improvesimultaneous cooling and heating operation capabilityVSAvoidinstallation area
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent removes the pipe unit that would occupy additional installation space by directly connecting outdoor units to the main high-pressure and low-pressure gas lines. This extraction eliminates the need for a separate pipe unit installation area, reducing the overall space required while maintaining full operational versatility.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If dedicated heat source outdoor units for cooling and heating operations are used, then the pipe unit is not needed, but the system cannot perform simultaneous cooling and heating operations

Engineering Contradiction:
Improvepipe unit eliminationVSAvoidsimultaneous cooling and heating operation capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The main high-pressure gas line and main low-pressure gas line are designed to universally handle refrigerant flow from multiple outdoor units performing different operations simultaneously. Each outdoor unit can independently connect to either line based on its operational mode, allowing the system to perform simultaneous cooling and heating without requiring dedicated units or a complex pipe unit.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of using dedicated outdoor units for cooling and heating (which would eliminate the need for pipe unit but reduce versatility), the patent inverts the approach by making the gas lines themselves multi-functional through direct connections, allowing a single type of outdoor unit to serve both cooling and heating purposes simultaneously.

Inventive Principle:
Principle #13The other way round (Inversion)

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 efficient, switchable cooling and heating operations with reduced installation area requirements and improved workability, as well as independent control of compressor capacities based on load demands, enhancing energy efficiency and user comfort.

Implementation Method 1

an outdoor heat exchanger one end of which is connected to a liquid line and the other end of which is connected to a gas line

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a compressor, an outdoor heat exchanger one end of which is connected to a liquid line and the other end of which is connected to a gas line

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2241843B1Refrigeration cycle apparatus
Publication Date: 2013.06.19 HITACHI APPLIANCES INC
  • EP2241843B1 patent drawingFigure 1
  • EP2241843B1 patent drawingFigure 2
  • EP2241843B1 patent drawingFigure 3

AI summary

The present invention provides a simultaneous cooling and heating type refrigeration cycle apparatus with a simple configuration using outdoor units (20a; 20b) in which a cooling operation and a heating operation can be performed in a switchable manner. There is provided a refrigeration cycle apparatus including: a first and a second outdoor units (20a; 20b), each including a compressor (1), an outdoor heat exchanger (2), a gas connection port (5), and a liquid connection port (6); a plurality of indoor units (21a; 21b; 21c) in which indoor liquid pipes, indoor heat exchangers (30), and indoor gas pipes (32) are connected in order; and a common liquid pipe through which the liquid connection port of each outdoor unit is communicated with the indoor liquid pipes (10a, 10b, 10c) in the plurality of indoor units (21a; 21b; 21c), wherein each of the indoor gas pipes in the respective indoor units (21a; 21b; 21c) is branched into a first gas pipe (11) and a second gas pipe (12), the first gas pipe (11) is connected to the gas connection port (5) of one of the outdoor units (20a; 20b), the second gas pipe (12) is connected to the gas connection port (5) of the other of the outdoor units (20b; 20a), pipe switching units (3), each switching the respective channels of the first gas pipe (11) and the second gas pipe (12) in each of the indoor units (21a; 21 b; 21c), and each of the indoor heat exchangers (30) is communicated with only one of the outdoor units (20a; 20b) by switching the pipe switching units (3).