Air conditioner

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Solution Overview

Problem

Air conditioner controllers face risks of malfunction and damage due to frost or condensation on refrigerant pipes, leading to potential damage from dripping liquids, and challenges in assembling refrigerant pipes with aluminum cooling jackets for effective heat transfer.

Innovation Solution

The air conditioner employs a condensation-prevention control system that adjusts fan speeds, expansion valve opening, and compressor speed to prevent condensation on refrigerant pipes, and uses a divided heat-conducting block configuration to facilitate close contact between refrigerant pipes and heat-generating components, ensuring efficient heat transfer and preventing liquid drainage issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the controller is cooled by using a refrigerant pipe between the outdoor heat exchanger and the expansion valve, then the cooling performance is improved, but the pipe may be damaged due to freezing caused by frost formation during heating operation

Engineering Contradiction:
Improvecooling performanceVSAvoidpipe damage risk
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent extracts the controller cooling function from the main refrigerant circulation path by selecting a specific refrigerant pipe location that carries liquid refrigerant at a temperature above freezing point, thereby separating the cooling function from the path susceptible to frost formation and pipe damage

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by selecting a specific segment of the refrigerant pipe (between outdoor heat exchanger and expansion valve) where the refrigerant maintains liquid state and temperature above freezing, creating a localized safe zone for controller cooling during heating operation

Inventive Principle:
Principle #3Local quality

2Temperature

If the controller is cooled by using the refrigerant pipe between the indoor heat exchanger and the expansion valve, then the cooling performance is improved, but condensation may occur on the refrigerant pipe surface causing electronic components to malfunction

Engineering Contradiction:
Improvecooling performanceVSAvoidcondensation damage
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the controller cooling function from the refrigerant pipe segment prone to condensation (between indoor heat exchanger and expansion valve) and relocates it to a pipe segment where refrigerant temperature remains above dew point, thereby separating the cooling function from condensation risk zones

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by selecting a specific refrigerant pipe location where local thermal conditions (liquid refrigerant at higher temperature) prevent condensation, creating a localized safe environment for controller cooling

Inventive Principle:
Principle #3Local quality

3Strength

If the aluminum cooling jacket and refrigerant pipe are brought into close contact by applying grease, then the thermal coupling is improved, but the assembly process becomes complicated

Engineering Contradiction:
Improvethermal couplingVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies self-service by designing the cooling jacket and refrigerant pipe with self-aligning features (protrusions and recesses) that automatically ensure proper contact and thermal coupling during assembly, eliminating the need for operator judgment and grease application

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the geometric parameters of the cooling jacket and refrigerant pipe interfaces (adding protrusions and recesses) to transform the assembly process from one requiring manual grease application to one that achieves automatic alignment and contact through geometric constraints

Inventive Principle:
Principle #35Parameter changes

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 solution enhances cooling performance, prevents malfunction and damage from condensation or frost, and simplifies the assembly process by ensuring effective thermal contact, thereby improving product quality and reliability.

Implementation Method 1

a refrigerant pipe between an outdoor heat exchanger and an expansion valve (in which high-pressure liquid refrigerant flows during cooling operation and low-pressure two-phase refrigerant flows during heating operation)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the condensation-prevention control portion, when a condition in which condensation is likely to occur on the refrigerant pipe is detected, performs control to prevent occurrence of condensation

Methodology Applied
Scientific EffectCondensation prevention: Condensation

Implementation Method 3

when frost forms on the refrigerant pipe during heating operation at a low outdoor air temperature, there is a risk of the pipe being damaged due to freezing caused by the frost formation

Methodology Applied
Scientific EffectFrost formation: Freezing

Data Source

PatentEP2876385B1Air conditioner
Publication Date: 2019.09.04 MITSUBISHI HEAVY IND THERMAL SYST
  • EP2876385B1 patent drawingFigure 1
  • EP2876385B1 patent drawingFigure 2
  • EP2876385B1 patent drawingFigure 3

AI summary

Provided is an air conditioner with which the occurrence of condensation when cooling a controller can be eliminated by a refrigerant pipe. Even if condensation or frost formation occurs, malfunctioning of the controller, damage to electronic components due to drain liquid can be prevented. The refrigerant pipe is placed in close contact with the controller. In an air conditioner (1) provided with a refrigeration cycle (11) and a controller (12) that is cooled during cooling operation by being in contact with a refrigerant pipe (10A) in which low-pressure two-phase refrigerant flows, a condensation-prevention control portion (24) is provided which, when a condition for condensation to occur on the refrigerant pipe (10A) is detected, the condensation is prevented by any one of rotational-speed control of an indoor fan (7), rotational-speed control of an outdoor fan (4), degree-of-opening control of an electronic expansion valve (6), and rotational-speed control of a compressor (2).