Rail Vehicle Heat Exchanger With Sealed Refrigerant Connection Boxes

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Solution Overview

Problem

The use of flammable refrigerants like hydrocarbons in air conditioning systems poses a safety risk due to the potential for leaks into occupied areas, such as passenger compartments, necessitating a design that ensures safe operation while maintaining a compact and efficient heat exchange.

Innovation Solution

A heat exchanger design with a refrigerant line assembly exposed between end plates and enclosed by sealing boxes at the connection points, ensuring fluid-tight separation of these points from the passenger compartment, using a sealing box that can be ventilated to prevent refrigerant leakage into the compartment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the refrigerant line assembly is exposed between end plates without housing, then heat exchange efficiency is improved and device complexity is reduced, but safety risk increases due to potential refrigerant leakage into the passenger compartment

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidrefrigerant leakage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The heat exchanger is divided into distinct functional zones: an exposed refrigerant line assembly area for efficient heat exchange and sealed end plate areas for safety containment. The end plates segment the exposed area from the connection points, creating clear functional separation between performance and safety functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The end plates serve as intermediary elements that bridge the exposed refrigerant line assembly and the sealed connection points. They provide a transition zone that maintains both the exposed configuration for heat exchange and the sealed configuration for safety, acting as a mediator between these conflicting requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If connection points are located outside the passenger compartment, then safety is improved by isolating leakage risks, but device complexity increases due to additional sealing structures

Engineering Contradiction:
Improvesafety against refrigerant leakageVSAvoidsealing box structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The end plates are merged with the sealing function, combining the structural support element with the safety containment element. This integration eliminates the need for separate sealing boxes while still achieving the safety objective of isolating connection points from the passenger compartment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The end plates perform multiple functions simultaneously: they provide structural support for the heat exchanger assembly, create sealed boundaries for safety containment, and serve as mounting surfaces for connection points. This multi-functionality reduces overall device complexity while maintaining safety.

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

3Productivity

If refrigerant lines are exposed for heat exchange, then heat exchange efficiency is improved, but reliability decreases due to increased vulnerability to leakage

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidrefrigerant leakage prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Different parts of the refrigerant line assembly have different properties: the exposed sections between end plates are designed for optimal heat exchange with open access to air flow, while the connection points at the end plates are designed with sealed interfaces for leakage prevention. This local differentiation of properties allows both efficiency and reliability requirements to be met simultaneously.

Inventive Principle:
Principle #3Local quality

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

Ensures safe operation with flammable refrigerants by containing leaks within the sealing box, maintaining a compact and efficient heat exchange design suitable for direct evaporating systems.

Implementation Method 1

a refrigerant line assembly for exchanging heat with air in a passenger compartment of the vehicle

Methodology Applied
Scientific EffectHeat exchange: Convection

Implementation Method 2

the heat exchanger comprises at least one sealing box that can be closed fluid-tight to the outside and is connected to the refrigerant line assembly at one end face

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP4647701A1Heat exchanger for vehicle
Publication Date: 2025.11.12 LIEBHERR TRANSPORTATION SYST
  • EP4647701A1 patent drawingFigure 1
  • EP4647701A1 patent drawingFigure 2
  • EP4647701A1 patent drawing

AI summary

The invention relates to a heat exchanger for a vehicle, in particular for a rail vehicle, comprising a refrigerant line assembly for heat exchange with air in a passenger area of ​​the rail vehicle, which is arranged between two opposing, end-face end plates and has no housing in the area between the end plates. The refrigerant line assembly includes connection points for the supply and discharge of refrigerant as well as fluid-tight line sections.According to the invention, the heat exchanger is designed for safety-critical refrigerants and comprises at least one sealing box that can be closed fluid-tight to the outside. This sealing box is connected to the refrigerant line assembly at one end face and forms or comprises the end plate there, through which refrigerant lines of the refrigerant line assembly are led into the interior of the sealing box. In the area free of the housing between the end plates, only fluid-tight sections of the refrigerant line assembly run, and preferably all connection points of the refrigerant line assembly are arranged within the at least one sealing box. The invention further relates to an air conditioning system and a vehicle with a heat exchanger according to the invention, as well as a method for manufacturing a heat exchanger according to the invention.