Air conditioner

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing air-conditioner technologies for multi-type systems face increased power consumption during washing operations due to separate washing of multiple indoor units, which leads to frequent compressor driving and inefficient energy use.

Innovation Solution

A refrigerant circuit and control system that coordinates the washing process across multiple indoor units, delaying the start of washing operations for units until a predetermined unit initiates freezing, thereby reducing compressor frequency and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If washing operation is performed separately for each indoor unit, then each indoor heat exchanger can be cleaned, but the compressor driving frequency increases and power consumption increases

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges washing operations across multiple indoor units by having them operate simultaneously or in coordinated sequence, utilizing the single outdoor unit's compressor and refrigerant circuit for all indoor units, thereby reducing total compressor driving frequency and power consumption while maintaining cleaning effectiveness for each indoor heat exchanger

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If washing operation is performed separately for each indoor unit, then each indoor heat exchanger can be cleaned, but the overall washing time increases

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidwashing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent combines washing operations for multiple indoor units into a coordinated process where the outdoor unit serves all indoor units simultaneously or in optimized sequence, reducing the total time required compared to separate washing operations while ensuring each indoor heat exchanger receives adequate cleaning

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If washing operation is performed separately for each indoor unit, then each indoor heat exchanger can be cleaned, but shared pipes are repeatedly cooled increasing power consumption per unit capacity

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidpower consumption per unit capacity
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent merges the washing operations so that shared refrigerant pipes are cooled only once or in coordinated sequence rather than repeatedly for each indoor unit, reducing the energy consumed by stationary components while maintaining cleaning effectiveness for all indoor heat exchangers

Inventive Principle:
Principle #5Merging (Combining)

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

The coordinated washing process reduces power consumption and shortens the overall washing time, improving energy efficiency and user convenience by minimizing interference with air-conditioning operations.

Implementation Method 1

Until a predetermined indoor unit included in the multiple indoor units starts the processing of freezing or forming dew on the indoor heat exchanger

Methodology Applied
Scientific EffectFreezing: Freezing

Implementation Method 2

Until a predetermined indoor unit included in the multiple indoor units starts the processing of freezing or forming dew on the indoor heat exchanger

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4116635B1Air conditioner
Publication Date: 2025.09.17 HITACHI JOHNSON CONTROLS AIR CONDITIONING INC
  • EP4116635B1 patent drawingFigure 1
  • EP4116635B1 patent drawingFigure 2
  • EP4116635B1 patent drawingFigure 3

AI summary

Provided is an air-conditioner achieving energy saving in washing of multiple indoor heat exchangers. The air-conditioner (100) includes a refrigerant circuit (Q) configured such that an outdoor unit (Uo) having a compressor (1) and an outdoor heat exchanger (2) and multiple indoor units (U1, U2, U3, U4) having indoor expansion valves (12) and indoor heat exchangers (10) are connected to each other through a pipe and a control section configured to control at least the compressor (1) and the multiple indoor expansion valves (12). Until a predetermined indoor unit (U1) included in the multiple indoor units (U1, U2, U3, U4) starts the processing of freezing or forming dew on the indoor heat exchanger (10), the control section does not start the processing for the other indoor units (U2, U3, U4).