Sewage Channel Heat Exchanger Layout for Long-Distance Energy Transport

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Solution Overview

Problem

The fluctuating temperature of wastewater due to rainwater mixing with household sewage reduces the efficiency of heat energy recovery in wastewater pipelines, leading to decreased thermal energy extraction at heat energy extraction points.

Innovation Solution

A heat exchanger arrangement is implemented in wastewater pipelines, where a first heat exchanger supplies heat energy to wastewater and a second heat exchanger, located downstream, extracts heat energy from the wastewater and transfers it to a heat sink, utilizing the existing sewage pipeline to transport thermal energy over distances without the need for separate supply lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If heat exchangers are installed in wastewater pipelines to recover heat energy, then thermal energy can be extracted from wastewater, but the efficiency decreases when rainwater mixes with household sewage and lowers the wastewater temperature

Engineering Contradiction:
Improveheat energy recovery efficiencyVSAvoidwastewater temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent applies preliminary action by heating the wastewater in advance at a first heat exchanger location upstream in the pipeline. This pre-heating ensures that even when rainwater mixing later reduces the temperature, the wastewater has already absorbed thermal energy that can be subsequently extracted at a second heat exchanger location downstream, thereby maintaining heat recovery efficiency despite temperature fluctuations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses the wastewater itself as an intermediary heat carrier to transport thermal energy from the first heat exchanger to the second heat exchanger through the pipeline. This intermediary approach allows heat to be moved over distances without requiring separate supply lines, while the wastewater's flow naturally carries the thermal energy despite temperature variations caused by rainwater mixing

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If heat exchangers are placed close together to maximize heat extraction, then thermal energy recovery is optimized, but the distance limitation restricts the ability to transport heat over long distances

Engineering Contradiction:
Improveheat energy extraction efficiencyVSAvoiddistance between heat exchangers
Core Design Contradiction:
Loss of energyVSLength of moving object

Solution Approach 1:

The patent makes the wastewater pipeline serve multiple functions: it simultaneously acts as both the transport conduit for wastewater and the heat transfer medium carrier. By using the existing pipeline infrastructure for both purposes, the system can transport heat over long distances without requiring additional dedicated heat supply lines, thus overcoming the distance limitation while maintaining heat extraction efficiency

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

Solution Approach 2:

The wastewater serves as a mobile intermediary that carries thermal energy from the first heat exchanger to the second heat exchanger over extended distances. The continuous flow of wastewater through the pipeline enables heat transport across long distances, with the thermal energy being transferred to a second heat exchange medium at the downstream location for delivery to heat sinks

Inventive Principle:
Principle #24Intermediary (Mediator)

3Length of moving object

If separate supply lines are installed to transport heat over long distances, then heat can be delivered to distant heat sinks, but the infrastructure cost and complexity increase significantly

Engineering Contradiction:
Improveheat transport distanceVSAvoidpipeline infrastructure
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent makes the existing wastewater pipeline perform dual functions: transporting wastewater and simultaneously serving as the heat transport medium conduit. This eliminates the need for separate dedicated heat supply lines, reducing infrastructure complexity and cost while enabling heat transport over the same long distances that the wastewater pipeline already covers

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

Solution Approach 2:

The system uses the wastewater's own flow through the existing pipeline to transport thermal energy without requiring additional pumping or infrastructure. The wastewater naturally carries the heat from the first heat exchanger to the second heat exchanger location, leveraging the existing pipeline's flow characteristics to provide self-service heat transport over long distances

Inventive Principle:
Principle #25Self-service

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 method enhances the recovery of thermal energy by maintaining optimal wastewater temperature and efficiently transporting heat energy over long distances, utilizing the existing sewage infrastructure to connect heat sources and sinks previously not economically viable.

Implementation Method 1

heating the waste water using the first heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

which is in thermal contact with a heat source

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

extracts heat energy from the waste water and transfers it to a heat sink

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

which is in thermal contact with the waste water

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2299186B1Method for transporting thermal energy in a sewage channel.
Publication Date: 2018.04.25 HELMUT UHRIG STRASSEN UND TIEFBAU
  • EP2299186B1 patent drawingFigure 1
  • EP2299186B1 patent drawingFigure 2

AI summary

The arrangement (1) has a heat exchanger (11) thermally contacting a heat source (13) with waste water (3). Another heat exchanger (21) thermally contacts the waste water with a heat sink (23). The latter heat exchanger is arranged downstream in a waste water pipe (5) along waste water flowing direction (F). The latter heat exchanger is placed at a distance from the former heat exchanger. A heat exchange medium (19) is supplied to the former heat exchanger by a hot water flow line (15). The heat exchange medium is supplied to the heat source by a cold water return line (17). The heat source is designed as a cooled industrially used machine. An independent claim is also included for a method for transporting heat energy.