Relay-Unit Air Conditioning for Leak-Safe Heat Medium Control

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Solution Overview

Problem

Existing air-conditioning systems for buildings face issues such as refrigerant leakage into indoor spaces, high energy consumption due to long heat medium circulation paths, poor construction ease, noise, and cost associated with secondary medium circulation, and inefficient heat exchange performance with non-azeotropic refrigerant mixtures, leading to uncomfortable temperature control and energy wastage.

Innovation Solution

An air-conditioning apparatus that uses a relay unit to transfer heat capacity from an outdoor unit to indoor units via a heat medium, avoiding direct refrigerant conveyance and allowing for comfortable heating or cooling operations by controlling the heat medium temperature, with a configuration of two pipes connecting the outdoor unit to the relay unit and two pipes connecting the relay unit to each indoor unit, facilitating energy saving and improved safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If refrigerant is circulated directly to indoor units, then heat exchange efficiency is improved, but refrigerant leakage into indoor spaces occurs

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidrefrigerant leakage
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a heat medium (water or antifreeze solution) as an intermediary substance that carries thermal energy between the outdoor heat source unit and indoor distribution units. This eliminates direct refrigerant contact with indoor spaces while maintaining effective heat transfer through the heat medium circulation system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If heat medium circulation path is made long to reach multiple indoor units, then coverage area is improved, but energy consumption increases

Engineering Contradiction:
Improvecoverage areaVSAvoidenergy consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent divides the heat medium circulation system into multiple independent loops, each serving specific indoor units. The heat source unit is segmented into multiple heat exchangers that can independently serve different zones, allowing optimized circulation paths for each segment rather than one long circulation path serving all units.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic flow control mechanisms including variable speed pumps and electronic expansion valves that adjust the heat medium flow rate and distribution in real-time based on actual heating or cooling demands of different indoor units, optimizing energy consumption regardless of circulation path length.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If four water pipes are used to connect outdoor unit to each indoor unit for simultaneous cooling and heating, then operational flexibility is improved, but construction complexity increases

Engineering Contradiction:
Improveoperational flexibilityVSAvoidconstruction complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent designs the heat medium circulation system with universal two-pipe connections that can serve both heating and cooling functions. By using flow direction control valves and reversible heat exchangers, the same pipe infrastructure supports dual operational modes, eliminating the need for separate four-pipe systems for each indoor unit.

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

4Use of energy by moving object

If secondary refrigerant system is used near each indoor unit, then heat exchange efficiency is improved, but noise and cost increase

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidnoise
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the noisy secondary refrigerant circulation components (pumps and heat exchangers) from the indoor unit locations and consolidates them in the outdoor heat source unit. The indoor units receive only the thermal energy through the heat medium circulation system, eliminating local noise sources while maintaining heat exchange efficiency through optimized outdoor equipment design.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution reduces energy consumption, enhances safety by minimizing refrigerant leakage, and ensures comfortable indoor temperatures by effectively controlling the heat medium temperature, improving both operational efficiency and user comfort.

Implementation Method 1

a heat exchanger included in an outdoor unit and it is conveyed to a fan coil unit or a panel heater, serving as an indoor unit, to perform heating or cooling

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

The refrigerant transfers or removes heat to or from air to heat or cool the air, thus heating or cooling an air-conditioned space with the heated or cooled air

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2927614B1Air conditioning device
Publication Date: 2020.08.05 MITSUBISHI ELECTRIC CORP
  • EP2927614B1 patent drawingFigure 1
  • EP2927614B1 patent drawingFigure 2
  • EP2927614B1 patent drawingFigure 3

AI summary

Upon switching of an air-conditioning apparatus 100 from an operation mode in which all of indoor units 3 each including a use side heat exchanger 35 are in non-operation to another operation mode in which at least one of the indoor units 3 starts a cooling operation mode or a heating operation mode, a heat medium conveyed to the use side heat exchanger 35 included in the indoor unit 3 which has received a start instruction is cooled or heated to a predetermined temperature by a heat source side refrigerant, and after that, an air-sending device included in the indoor unit 3 which starts the cooling operation mode or the heating operation mode is actuated.