Rail Vehicle Air Conditioning Using Coanda Flow Influence

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Solution Overview

Problem

Existing vehicle air conditioning systems, particularly in rail vehicles, face challenges in uniform air distribution, leading to uneven heating and cooling in certain areas, requiring complex ductwork and increased construction costs.

Innovation Solution

A method utilizing a first air flow generated by an air conditioning system and a second air flow from an additional air recirculation device, where the second air flow influences the first air flow regarding direction and intensity, using Coand effect to distribute air uniformly throughout the vehicle interior via convex inflow openings, reducing the need for complex ducts and fans.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If heated air is blown out in one direction via conventional air conditioning systems, then the system structure is simple, but the air distribution becomes uneven in certain areas

Engineering Contradiction:
Improvesystem structureVSAvoidair distribution uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The air flow is divided into two separate streams: a first air flow from the air conditioning system and a second air flow from the recirculation device. This segmentation allows each stream to serve specific functions - the first stream provides conditioned air while the second stream modifies flow direction and distribution patterns, collectively achieving uniform air distribution without requiring complex ductwork.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second air flow acts as an intermediary that influences the first air flow. By introducing this intermediate air stream through strategically positioned inlet openings, the system can redirect and distribute the first air flow more uniformly throughout the interior space, solving the air distribution problem without adding complex heating ducts.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If floor area heating is used to provide heated air, then air distribution coverage is improved, but large ducts are required which increase construction effort

Engineering Contradiction:
Improveair distribution coverageVSAvoidductwork complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The invention extracts the flow direction control function from the heating system itself and places it in the recirculation device. The second air flow from the recirculation device is used to influence the direction and distribution of the first air flow, separating the heating function from the flow control function and eliminating the need for large heated air ducts in the floor area.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The recirculation device serves multiple functions: it recirculates air, controls flow direction, and influences air distribution patterns. By making the recirculation device multi-functional, the system achieves comprehensive air distribution without requiring separate dedicated ducts for each function, thereby reducing overall construction effort.

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

3Reliability

If separate ducts are used for exhaust air extraction and recirculated air return, then air handling is complete, but construction effort increases

Engineering Contradiction:
Improveair handling completenessVSAvoidductwork complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the exhaust air extraction and recirculated air return functions into a single integrated recirculation device. This device handles both functions through unified airflow management, maintaining complete air handling while eliminating the need for separate ducts for each function, thereby reducing construction effort.

Inventive Principle:
Principle #5Merging (Combining)

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 approach enables cost-effective, reliable, and even air conditioning, avoiding strong currents in seating areas, thus creating a comfortable climate with reduced structural complexity and construction costs.

Implementation Method 1

At least one inlet channel for supplying the second airflow into the interior is designed as a convex Coand inlet opening and is arranged in the interior such that, according to the Coand effect, the first airflow adheres to surfaces in the interior in such a way that the first airflow, influenced by the second airflow, does not directly enter the seating areas of the interior

Methodology Applied
Scientific EffectCoand effect: Coanda Effect

Data Source

PatentEP3065993B1Method for air conditioning a vehicle, in particular a rail vehicle
Publication Date: 2020.02.05 SIEMENS MOBILITY GMBH
  • EP3065993B1 patent drawingFigure 1
  • EP3065993B1 patent drawingFigure 2
  • EP3065993B1 patent drawing

AI summary

The invention relates to a method for air conditioning a vehicle, in particular a rail vehicle, in which a first air flow is generated by an air conditioning system for air conditioning an interior, as a result of which the interior of the vehicle is fed cooled air as feed air in a cooling mode and is fed heated air as feed air in a heating mode, wherein a second air flow generated by an additional air circulating device is fed to the interior of the vehicle in such a way that the second air flow influences the first air flow, in particular with regard to flow direction and flow intensity. The invention also relates to a vehicle, in particular a rail vehicle, comprising an interior, an air conditioning system and an additional air circulating device, wherein a second air flow influences a first air flow, in particular with regard to flow direction and flow intensity.