Roof-Mounted Rail Air Conditioning System with Segmented Modules

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Solution Overview

Problem

Existing air conditioning systems for rail vehicles face challenges in providing high-quality air conditioning, especially during extensive tunnel journeys, due to issues with air supply and exhaust in narrow tunnel contours, and mechanical loads, while also being difficult to handle and maintain.

Innovation Solution

A compact air conditioning system with a compressor/condenser unit and air treatment unit arranged in a device tray on the vehicle roof, featuring two separate refrigeration circuits, microchannel condensers, and an air treatment unit with an evaporator, heater, and UV lamps, designed for efficient air distribution and handling, including a mechanism to regulate outside and recirculating air ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If air conditioning components are arranged in a common chamber enclosed by a housing, then the system provides sufficient air treatment capacity, but the roof shape is increased

Engineering Contradiction:
Improveair treatment capacityVSAvoidroof shape
Core Design Contradiction:
Quantity of substanceVSShape

Solution Approach 1:

The air conditioning system is divided into multiple functional modules (compressor unit, condenser unit, evaporator unit, air treatment unit) that are arranged in series along the roof surface. Each module handles a specific function, allowing the system to maintain adequate air treatment capacity while distributing the volume along the roof rather than concentrating it in a single elevated chamber.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a vertical stacking arrangement (which would increase roof height) to a horizontal linear arrangement along the roof surface. The components are positioned in a longitudinal sequence from front to rear of the vehicle, utilizing the length dimension of the roof rather than the height dimension, thereby maintaining a low profile while preserving functional capacity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If air ducts are arranged for fresh air supply and exhaust air discharge, then air conditioning function is provided, but exhaust air flows back into fresh air flow in narrow tunnel contours

Engineering Contradiction:
Improveair conditioning functionVSAvoidexhaust air flow back
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The exhaust air discharge function is extracted and positioned at the rear end of the air conditioning system, separated from the fresh air intake path. The exhaust air outlet is located at the rear of the housing while fresh air is drawn from the front and sides, creating spatial separation that prevents exhaust air from flowing back into the fresh air intake, especially important when operating in narrow tunnel contours.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The traditional arrangement where exhaust outlets are positioned near the center or front is inverted. Instead, the exhaust air discharge is positioned at the extreme rear of the system, while fresh air intake is positioned at the front and sides. This reversed spatial arrangement ensures that exhaust air is discharged away from the fresh air intake path, preventing contamination even in confined tunnel environments.

Inventive Principle:
Principle #13The other way round (Inversion)

3Volume of moving object

If components are installed in an equipment tray on the vehicle roof, then the system is compact and fits in free installation space, but handling during assembly and maintenance is impaired

Engineering Contradiction:
Improvesystem compactnessVSAvoidassembly and maintenance handling
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The air conditioning system is segmented into multiple independently accessible functional modules arranged in a linear sequence. Each module (compressor, condenser, evaporator, air treatment) can be accessed and serviced separately. The longitudinal arrangement allows maintenance personnel to reach each component from the side or rear without having to disassemble the entire system, improving handling during assembly and maintenance while maintaining overall compactness.

Inventive Principle:
Principle #1Segmentation

4Reliability

If larger quantities of fresh air are supplied after pressure protection events, then passenger air quality is improved, but larger volume flows and expanded technical capacities are required

Engineering Contradiction:
Improvepassenger air qualityVSAvoidtechnical capacity requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The air treatment unit incorporates variable capacity components including variable speed fans and controllable dampers that can dynamically adjust volume flow rates. The system can operate at different capacity levels depending on operational requirements - normal operation uses standard capacity, while post-pressure-event scenarios trigger high-capacity fresh air intake mode. This dynamic capability allows the system to meet expanded technical capacity requirements only when needed, without permanently increasing device complexity.

Inventive Principle:
Principle #15Dynamics

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 high-quality air conditioning in rail vehicles, particularly in underground environments, with enhanced ease of installation and maintenance, and improved structural integrity for mechanical loads.

Implementation Method 1

two condenser fans (2), wherein the condenser intake air is sucked in by the fans

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

an air treatment unit (6) with an evaporator (6)

Methodology Applied
Scientific EffectHeat Exchanger: Heat Exchanger

Implementation Method 3

an air treatment unit (6) with an evaporator (6), a heater (7)

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP2755878B1Air conditioning system for rail vehicles
Publication Date: 2018.08.29 FAIVELEY TRANSPORT LEIPZIG GMBH & CO KG
  • EP2755878B1 patent drawingFigure 1
  • EP2755878B1 patent drawingFigure 2
  • EP2755878B1 patent drawingFigure 3

AI summary

The invention relates to an air-conditioning system for rail vehicles, wherein all components necessary for air-conditioning the passenger compartment, in particular compressor, condenser, fan, filters, heating elements, sensor systems and controller are structurally integrated into an equipment tray arranged on the vehicle roof and wherein this equipment tray enclosed by a casing is arranged in a free construction space on the vehicle roof in such a manner that it forms part of the roof shape inside the contour of the rail vehicle. The task of the invention is to create an air conditioning system that is suitable in particular for rail vehicles used as underground railways. The problem is solved by a specific design of the components for air handling and air distribution, as a result of which high-quality air-conditioning is guaranteed even during prolonged travel in tunnels.