Air Conditioner Bypass Line Design for High-Pressure Event Control

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Solution Overview

Problem

Air conditioners experience high-pressure events during changes in operation, leading to refrigerant accumulation and potential mechanical failure or shutdown due to pressure spikes, which existing technologies fail to effectively manage.

Innovation Solution

An air conditioner system with a bypass line and secondary expansion device allows a portion of refrigerant to bypass the primary expansion device during high-pressure events, using a controller to manage refrigerant flow and prevent shutdown by adjusting the thermal expansion valve based on temperature and pressure conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If refrigerant flow is restricted through the primary expansion device during high-pressure events, then pressure control is improved, but system shutdown occurs due to high pressure switch trip

Engineering Contradiction:
Improvepressure controlVSAvoidsystem continuity
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

A bypass line with a secondary expansion device is introduced as an intermediary pathway. During high-pressure events, the controller redirects a portion of the refrigerant flow through this bypass line, allowing pressure relief while maintaining continuous system operation. The bypass line acts as a mediator between the primary expansion device and the system's pressure management needs.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically switches between normal operation mode and high-pressure bypass mode based on real-time pressure conditions. The controller monitors pressure levels and automatically activates the bypass line when high-pressure events are detected, then deactivates it when pressure returns to normal. This dynamic adaptation allows the system to respond flexibly to changing operating conditions.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a bypass line with secondary expansion device is added to manage high-pressure events, then system reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesystem continuityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bypass line with the secondary expansion device serves multiple functions: it acts as a pressure relief pathway during high-pressure events, provides an alternative refrigerant flow route, and works in conjunction with the controller to dynamically manage system operation. This multi-functionality justifies the added complexity by delivering comprehensive pressure management and system protection capabilities.

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

3Quantity of substance

If refrigerant accumulates in the air conditioner during operation changes, then pressure spikes occur, but existing technologies fail to effectively manage these events

Engineering Contradiction:
Improverefrigerant accumulationVSAvoidpressure spikes
Core Design Contradiction:
Quantity of substanceVSStress or pressure

Solution Approach 1:

The controller continuously monitors pressure conditions in the system and uses this feedback to determine when to activate the bypass line. When high-pressure events are detected, the controller redirects refrigerant flow through the bypass line to prevent further pressure buildup. This feedback mechanism enables real-time pressure management and prevents harmful pressure spikes during operation changes.

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 solution inhibits shutdown and reduces pressure spikes, preventing mechanical failure by allowing refrigerant to flow through a secondary expansion device, thus maintaining air conditioner operation during high-pressure events.

Implementation Method 1

The thermal expansion valve may include a bulb and a heat transfer element. A temperature of the bulb may at least partially control an amount of refrigerant allowed to pass through the thermal expansion valve.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The controller may allow heat transfer between at least one of the heat transfer elements and the bulb to alter a temperature of the bulb prior to allowing the first portion of the refrigerant to bypass the primary expansion valve

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3457053B1Managing high pressure events in air conditioners
Publication Date: 2024.01.03 LENNOX IND INC
  • EP3457053B1 patent drawingFigure 1
  • EP3457053B1 patent drawingFigure 2~3
  • EP3457053B1 patent drawingFigure 4

AI summary

In various implementations, an air conditioner (100) may include one or more compressors (120, 130), more than one expansion device (150, 155), and/or a microchannel condenser (110). High pressure events may occur during operation of the air conditioner (100) and may be identified (210). When a high pressure event is identified (210) a bypass operation may be allowed (220).