Expansion Valve Control for Occupancy-Based Refrigerant Distribution

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Solution Overview

Problem

Existing air-conditioning systems face inefficiencies in power consumption reduction and user comfort due to inadequate refrigerant distribution based on the number of people in each room, leading to potential misoperation and discomfort.

Innovation Solution

An air-conditioning apparatus with human detection sensors and control mechanisms that adjust the refrigerant supply to indoor units by controlling the opening degrees of expansion devices, ensuring efficient refrigerant distribution according to the number of people in each room.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the temperature setting is automatically changed when users are absent to reduce air conditioning load, then power consumption is reduced, but user comfortability deteriorates due to inadequate refrigerant distribution

Engineering Contradiction:

Improvepower consumptionVSAvoiduser comfortability

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

The system adjusts refrigerant distribution to each indoor unit based on the number of people detected in each room. When users are absent, the system reduces refrigerant supply to those specific rooms rather than uniformly changing temperature settings across all rooms, thereby reducing power consumption while maintaining comfort in occupied spaces.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The control device changes the opening degree of expansion valves (parameter change) based on human detection results to optimize refrigerant distribution. This dynamic parameter adjustment allows the system to reduce power consumption by matching refrigerant supply with actual occupancy conditions in each room.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If refrigerant is not distributed according to the number of people in each room, then device complexity is reduced, but compressor efficiency deteriorates

Engineering Contradiction:

Improvecontrol complexityVSAvoidcompressor efficiency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system uses human detection devices to provide feedback on occupancy status in each room. Based on this feedback, the control device automatically adjusts the opening degree of expansion valves to optimize refrigerant distribution, thereby maintaining high compressor efficiency without requiring complex manual intervention.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The air conditioning system automatically adjusts its own refrigerant distribution based on occupancy detection. The control device autonomously optimizes the opening degrees of expansion valves according to the number of people in each room, eliminating the need for user manipulation while maintaining compressor efficiency.

Inventive Principle:

Principle #25Self-service

3Loss of energy

If manual temperature setting changes are required to reduce power consumption, then refrigerant distribution can be optimized, but ease of operation deteriorates due to user manipulation requirements

Engineering Contradiction:

Improvepower consumptionVSAvoiduser manipulation

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

The system automatically detects user presence or absence using human detection devices and autonomously adjusts the opening degree of expansion valves accordingly. This self-service mechanism eliminates the need for user manipulation while optimizing refrigerant distribution and reducing power consumption.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The control device continuously receives feedback from human detection devices and automatically adjusts refrigerant distribution based on occupancy status. This closed-loop control system reduces power consumption without requiring user intervention, as the system self-adjusts based on real-time occupancy information.

Inventive Principle:

Principle #23Feedback

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 enables high-efficiency power consumption reduction while enhancing user comfort by optimizing refrigerant distribution and temperature settings, reducing wasteful operations and improving room conditioning effectiveness.

Implementation Method 1

controls an amount of refrigerant supplied to the use side heat exchangers by controlling opening degrees of the expansion devices

Methodology Applied

Scientific EffectRefrigerant expansion and phase change: Phase Change

Implementation Method 2

heat source side heat exchanger, a plurality of use side heat exchangers being connected by refrigerant piping constituting a refrigeration cycle

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentUS10088193B2Air-conditioning apparatus including a controller that controls opening degrees of expansion valves based on detection results of human detection devices

Publication Date: 2018.10.02 MITSUBISHI ELECTRIC CORP

AI summary

Human detection devices 8 that detect the number of people in conditioned spaces supplied with conditioned air from the use side heat exchangers 12 and control means 9 and 50 that controls an amount of refrigerant supplied to the use side heat exchangers 12 by controlling opening degrees of the expansion devices 5 on the basis of detection results of the human detection devices 8.