Hybrid multi-air conditioning system

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Solution Overview

Problem

Conventional hybrid multi-air conditioning systems face issues such as varying condensation heat due to water temperature changes, pressure drops causing two-phase refrigerant entry, reduced cooling capacity, and compressor damage, along with inefficient supercooling and simultaneous operation challenges during hot water supply and cooling.

Innovation Solution

A hybrid multi-air conditioning system with a hot water supply unit, indoor and outdoor devices, and controlled expansion valves, allowing for series operation of heat exchangers and direct refrigerant-water exchange, preventing two-phase refrigerant entry, and optimizing supercooling through temperature and pressure sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the refrigerant-side condensation heat exchanger is directly wound around the water tank, then the condensation heat amount varies according to water temperature and user water consumption, but the control point of the water tank condenser changes causing unstable operation

Engineering Contradiction:
Improvecondensation heat controlVSAvoidcontrol point stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the condensation heat exchange system into two separate heat exchangers: one for the water tank and one for the outdoor device. This segmentation allows independent control of each heat exchanger's operation, preventing the control point instability that occurs when a single heat exchanger must serve dual purposes. The refrigerant flow can be directed to either heat exchanger based on operational requirements, maintaining stable control points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control of refrigerant flow distribution between the water tank heat exchanger and outdoor device heat exchanger through expansion valves and control logic. The system can dynamically switch between different operational modes (hot water supply only, cooling only, or simultaneous operation) by adjusting valve openings and refrigerant flow paths, allowing adaptability without compromising control stability.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If two expansion valves are installed for hot water supply and outdoor device, then refrigerant must pass through two valves causing excessive pressure loss, but if one valve is used the refrigerant flow control becomes insufficient

Engineering Contradiction:
Improverefrigerant flow controlVSAvoidpressure loss
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The patent extracts the pressure loss problem by reconfiguring the refrigerant flow path. Instead of forcing refrigerant through two expansion valves in sequence, the system uses one expansion valve to control refrigerant flow to the water tank heat exchanger, and another expansion valve for the outdoor device heat exchanger, with the ability to bypass or selectively activate paths to minimize cumulative pressure loss while maintaining control flexibility.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the operational parameters of the expansion valves dynamically based on system requirements. The control logic adjusts valve opening degrees, refrigerant flow rates, and heat exchanger activation states to optimize the balance between flow control precision and pressure loss minimization for different operational modes.

Inventive Principle:
Principle #35Parameter changes

3Stress or pressure

If the opening of expansion valve is too small, then pressure loss occurs and two-phase refrigerant enters the expansion valve, but if opening is large the evaporation temperature reduces causing cycle hunting

Engineering Contradiction:
Improvepressure lossVSAvoidevaporation temperature
Core Design Contradiction:
Stress or pressureVSTemperature

Solution Approach 1:

The patent implements feedback control through sensors that monitor refrigerant temperature, pressure, and flow conditions at various points in the system. The control logic uses this feedback information to dynamically adjust expansion valve openings, ensuring that valves operate in the optimal range that prevents both excessive pressure loss and two-phase refrigerant entry, while maintaining stable evaporation temperatures and preventing cycle hunting.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system performs preliminary assessment of system conditions (temperature differential, cooling load, water tank temperature) before determining expansion valve openings. This preliminary action allows the system to pre-calculate optimal valve positions that will maintain proper refrigerant phase and temperature conditions, preventing the need for reactive adjustments that could cause instability.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If condensation temperature increases on water tank side, then compressor may be damaged, but if cooling capacity is reduced by lowering compressor frequency, then cooling performance deteriorates

Engineering Contradiction:
Improvecompressor protectionVSAvoidcooling capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic operational modes that allow the system to adapt compressor operation and heat exchanger configuration based on real-time conditions. When hot water supply is required, the system can operate in a mode where the water tank heat exchanger serves as the primary condenser, with the compressor frequency and refrigerant flow dynamically adjusted to maintain safe condensation temperatures while preserving adequate cooling capacity through coordinated control of multiple components.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (compressor frequency, expansion valve openings, heat exchanger activation) based on the operational mode. During simultaneous hot water supply and cooling operation, the control logic adjusts these parameters to balance compressor protection (maintaining safe condensation temperatures) with cooling performance (maintaining adequate cooling capacity), preventing the need to choose one over the other.

Inventive Principle:
Principle #35Parameter changes

5Productivity

If heat exchangers are operated in series for hot water supply and cooling, then refrigerant flow rate in superheating section increases improving hot water performance, but system complexity increases

Engineering Contradiction:
Improvehot water supply performanceVSAvoidheat exchanger configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the heat exchanger system into distinct functional units (water tank heat exchanger and outdoor device heat exchanger) that can be connected in series or parallel or operated independently based on requirements. This segmentation enables the series configuration for improved hot water performance when needed, while maintaining the option to use simpler configurations for other operations, thus managing complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs the heat exchanger system with multi-functionality, where each heat exchanger can serve different purposes depending on operational mode: the water tank heat exchanger can function as a condenser for hot water supply, the outdoor device heat exchanger can function as a condenser for cooling, and they can be combined in series for simultaneous operation. This universality allows the system to achieve improved hot water performance through series operation without permanently increasing complexity, as the complex configuration is only activated when needed.

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

Stabilizes the refrigeration cycle, prevents compressor damage, enhances cooling capacity, and enables efficient simultaneous hot water supply and cooling operations by optimizing heat exchanger usage and refrigerant flow control.

Implementation Method 1

a hot water supply heat exchanger for exchanging heat between the refrigerant and water accommodated in the water tank

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

an outdoor heat exchanger, a compressor, and an outdoor expansion valve

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a compressor

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

a first hot water supply expansion valve for blocking or flowing the refrigerant condensed from the hot water supply heat exchanger

Methodology Applied
Scientific EffectExpansion: Pressure Drop

Data Source

PatentEP4310416B1Hybrid multi-air conditioning system
Publication Date: 2026.02.25 LG ELECTRONICS INC
  • EP4310416B1 patent drawingFigure 1
  • EP4310416B1 patent drawingFigure 2
  • EP4310416B1 patent drawingFigure 3

AI summary

The present disclosure relates to a hybrid multi-air conditioning system. The hybrid multi-air conditioning system of the present disclosure includes a hot water supply unit including a hot water supply heat exchanger for exchanging heat between the refrigerant and water accommodated in the water tank and a first hot water supply expansion valve for blocking or flowing the refrigerant condensed from the hot water supply heat exchanger; at least one indoor device installed indoors and including an indoor heat exchanger and an indoor expansion valve; an outdoor device connected to the indoor device and the hot water supply unit through a refrigerant pipe and including an outdoor heat exchanger, a compressor, and an outdoor expansion valve; a second hot water supply discharge pipe having one side branched from the first hot water supply discharge pipe connecting the hot water supply heat exchanger and the indoor heat exchanger and the other side joining the first discharge pipe connecting the compressor and the outdoor heat exchanger; and a second hot water supply expansion valve installed on the second hot water supply discharge pipe.