Geothermal Tubular Heat Exchanger for Railway Switch De-Icing

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Solution Overview

Problem

Existing heat exchanger technologies for railway switches and rail crossings face challenges such as high energy consumption, inefficient heat transfer, complex and costly manufacturing, and space constraints, leading to ineffective snow and ice melting, especially in narrow track spacings and rail crossings.

Innovation Solution

A longitudinally tubular heat exchanger with a condensation chamber surrounded by an extruded profile main component, featuring a chamber ceiling, side walls, and end openings, designed for efficient heat transfer and adaptable to different track sleeper distances, using geothermal energy with a heat transfer medium like carbon dioxide to melt snow and ice effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electric heaters or gas/oil burners are used to heat switches, then snow and ice can be melted, but energy consumption and operating costs become excessively high

Engineering Contradiction:
Improvesnow and ice melting effectivenessVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent utilizes the phase transition of heat transfer medium (water) between liquid and vapor states to enable efficient heat transfer. The medium evaporates in the evaporator section absorbing heat from geothermal source, then condenses in the condensation section releasing heat to melt snow and ice, achieving reliable de-icing with minimal energy input from renewable geothermal source

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The patent replaces conventional electric heating systems or combustion-based heaters with a geothermal heat pump system that utilizes natural geothermal energy. This substitution eliminates the need for high energy consumption electrical heaters or fuel-based burners, achieving snow and ice melting through natural heat transfer from geothermal source

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If geothermal heat pipes with tubular condensation areas are used, then snow and ice can be melted, but the heating radius remains too small and snow accumulates in unheated areas

Engineering Contradiction:
Improvesnow and ice melting capabilityVSAvoidheating area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent divides the heat exchanger into multiple independent heat transfer channels within the condensation section. By segmenting the heat transfer path into multiple parallel channels, the effective heating surface area is increased, allowing heat to be distributed across a larger area to melt snow and ice more comprehensively and prevent accumulation in unheated zones

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-tube heat pipe design to a multi-channel plate heat exchanger configuration. This dimensional change from one-dimensional heat transfer through a single tube to two-dimensional heat distribution across multiple channels significantly expands the effective heating area and improves snow and ice melting coverage

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

3Area of stationary object

If mini-channels are introduced into heat exchangers to increase heating area, then more snow and ice can be melted, but manufacturing costs and complexity increase significantly

Engineering Contradiction:
Improveheating areaVSAvoidmanufacturing cost
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent changes the geometric parameters of the heat exchanger channels from conventional small-diameter mini-channels to larger cross-sectional area channels. This parameter change reduces manufacturing complexity and cost while still achieving increased heating area through multiple parallel channels, making the system more economically viable

Inventive Principle:
Principle #35Parameter changes

4Strength

If heat exchangers with large wall thicknesses are used to withstand high operating pressures, then structural strength is improved, but heat conduction efficiency and material costs deteriorate

Engineering Contradiction:
Improvepressure resistanceVSAvoidheat conduction efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent employs composite construction for the heat exchanger walls, combining materials with different properties to achieve both high pressure resistance and efficient heat conduction. The composite structure allows thin walls that conduct heat effectively while still withstanding high operating pressures through material composition rather than increased thickness

Inventive Principle:
Principle #40Composite materials

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

The solution allows for efficient snow and ice melting with minimal heat energy, is cost-effective to produce in large quantities, withstands high operating pressures, and occupies less space, ensuring effective clearance of snow and ice between track sleepers while maintaining operational reliability.

Implementation Method 1

The heat transfer medium is heated and evaporated in the evaporator area. It then rises due to the lower density, especially through the transport area to the condensation area.

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

At low ambient temperatures, the heat transfer medium finally condenses in the tubular condensation area and releases heat to the tube wall.

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

The heat transfer medium is heated and evaporated in the evaporator area... releases heat to the tube wall. The latter is thermally coupled to the switch

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

It then rises due to the lower density, especially through the transport area to the condensation area

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP2904150B1Heat exchanger for rails and switches
Publication Date: 2017.11.29 PINTSCH BAMAG AG
  • EP2904150B1 patent drawingFigure 1
  • EP2904150B1 patent drawingFigure 2
  • EP2904150B1 patent drawingFigure 3

AI summary

Known heat exchangers for switches are expensive to produce or unsuitable for heating variable surfaces. The aim of the invention is to provide a low-maintenance heat exchanger which can be produced cost-effectively in large quantities, efficiently melts snow and ice, can be connected to a geothermal heat pipe and can be used in the region of a switch, especially in a sleeper space. The invention therefore relates to a heat exchanger comprising a condensation chamber, a connecting opening for connection to a geothermal heat pipe leading into said condensation chamber. The condensation chamber is radially surrounded by a tubular main part in the longitudinal direction and has a chamber ceiling, an opposite chamber base and two sidewalls connecting the chamber ceiling to the chamber base. The main part has two end openings of the condensation chamber in the longitudinal direction, which openings are closed by respective covers.