Air Conditioner Bypass Expansion Control for High Pressure Events

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Air conditioners experience pressure spikes during transitions in operation, leading to potential shut down due to refrigerant accumulation, which existing technologies fail to manage effectively, resulting in mechanical failure and inefficiency.

Innovation Solution

The implementation of a system that allows a portion of refrigerant to bypass the primary expansion device and flow through a secondary expansion device, managed by a controller that identifies high pressure events based on stored criteria, including ambient temperature and pressure, to prevent shut down and maintain efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If refrigerant flow is restricted through the primary expansion device during operation transitions, then pressure control is improved, but refrigerant accumulation occurs causing high pressure events

Engineering Contradiction:
Improvepressure controlVSAvoidrefrigerant accumulation
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The refrigerant flow path is segmented into two separate paths: a primary expansion device and a bypass line with a secondary expansion device. This segmentation allows independent control of refrigerant flow through each path, enabling the system to manage pressure and prevent accumulation by directing flow through the appropriate path during different operating conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bypass line acts as an intermediary path that provides an alternative route for refrigerant flow when the primary expansion device cannot adequately manage pressure. The bypass line with its secondary expansion device serves as a mediator to relieve high pressure events without disrupting the primary refrigeration cycle.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a bypass line with secondary expansion device is added, then high pressure events are managed, but device complexity increases

Engineering Contradiction:
Improvehigh pressure event managementVSAvoidsystem 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 path during high pressure events, provides an alternative refrigerant flow route during transitions, and can be integrated with existing expansion devices (thermal expansion valves, electronic expansion devices). This multi-functionality justifies the added complexity by providing robust pressure management.

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

Solution Approach 2:

The bypass line is designed to activate automatically during high pressure events without requiring external intervention. The secondary expansion device self-regulates refrigerant flow through the bypass line based on system conditions, eliminating the need for complex control mechanisms and reducing operational complexity.

Inventive Principle:
Principle #25Self-service

3Stress or pressure

If refrigerant flow is redirected through the bypass line, then pressure spikes are reduced, but flow control precision may be compromised

Engineering Contradiction:
Improvepressure spike reductionVSAvoidflow control precision
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The secondary expansion device in the bypass line uses adjustable parameters (such as orifice size, thermal characteristics of bulb, or electronic control settings) to optimize flow control for pressure management. By tuning these parameters, the system achieves precise control over bypass flow rates, ensuring effective pressure spike reduction while maintaining adequate flow control precision.

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 inhibits shut down and mechanical failure by reducing pressure spikes during high pressure events, allowing continuous operation and reducing the risk of refrigerant accumulation, thereby enhancing the reliability and efficiency of air conditioner performance.

Implementation Method 1

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)

Implementation Method 2

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

Data Source

PatentEP2916087B1Managing high pressure events in air conditioners
Publication Date: 2018.09.19 LENNOX IND INC
  • EP2916087B1 patent drawingFigure 1
  • EP2916087B1 patent drawingFigure 2~3
  • EP2916087B1 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).