Subsurface Heating System with Conductive Casing

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Solution Overview

Problem

Conventional methods require separate boreholes for thermal conduction heating and electrical resistance heating (ERH), increasing costs and complexity when dealing with subsurface media of varying electrical and thermal conductivity, necessitating multiple drilling efforts.

Innovation Solution

A combination subsurface heating system that integrates ERH and thermal conduction heating within the same borehole using an electrically conductive casing with an internally isolated heating element, powered by separate sources, allowing for adjustable placement to target contaminants effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two separate bore holes are installed for thermal conduction heating and electrical resistance heating, then each heating method can be applied independently to treat different lithological units, but the drilling cost and installation complexity double

Engineering Contradiction:

Improveability to treat different lithological unitsVSAvoidnumber of bore holes required

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines thermal conduction heating and electrical resistance heating into a single integrated system installed in one borehole. The system includes an electrically conductive well casing that serves dual purposes: it acts as a thermal conduction heater when electrical current flows through it, and simultaneously serves as an electrode for electrical resistance heating of surrounding subsurface materials. This merging eliminates the need for separate boreholes for each heating method, reducing drilling costs and installation complexity while maintaining the ability to treat different lithological units with varying electrical and thermal conductivity.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If two separate bore holes are used for ERH electrodes targeting different lithologies, then each lithology can receive proportional voltage potential, but the installation cost increases

Engineering Contradiction:

Improveinstallation costVSAvoidtargeting different lithologies

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The well casing is designed to perform multiple functions simultaneously: it serves as a structural component of the borehole, a thermal conduction heater for treating subsurface materials, and an electrode for electrical resistance heating. By applying electrical current through the conductive casing, the system can deliver proportional voltage potentials to different lithological units based on their electrical conductivity requirements, all through a single installation rather than requiring separate boreholes for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If thermal conduction heating and electrical resistance heating are performed in separate bore holes, then each method operates independently, but the overall treatment efficiency decreases

Engineering Contradiction:

Improvetreatment efficiencyVSAvoidoperational independence

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The system merges thermal conduction heating and electrical resistance heating operations into a single integrated system. The electrically conductive well casing receives electrical current that generates heat through both mechanisms simultaneously: thermal conduction heating as heat transfers from the casing to surrounding materials, and electrical resistance heating as current passes through subsurface materials with electrical resistance. This combined operation in one borehole increases treatment efficiency by delivering both heating mechanisms to the same target zone, while the system remains operationally flexible allowing independent control of heating parameters.

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 reduces installation costs and complexity by enabling simultaneous or sequential use of both heating methods in a single borehole, providing efficient heat delivery to contaminants regardless of subsurface conductivity variations.

Implementation Method 1

electrical resistance heating (ERH) electrodes. The subsurface media are resistant to the flow of electricity, and therefore, heat is produced

Methodology Applied

Scientific EffectElectrical resistance heating: Joule Heating

Implementation Method 2

thermal conduction heater wells are heating devices that are typically placed into the ground or soil pile to deliver heat energy into a contaminated media

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The increased temperature may cause a phase change, enabling removal of volatile contaminants

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS10987710B2Thermal conduction heater well and electrical resistance heating electrode

Publication Date: 2021.04.27 PARSONS CORPROATION

AI summary

A combination subsurface heating system that incorporates electrical resistance heating and thermal conduction heating with systems disposed within a single borehole. The combination heating system includes an electrically conductive outermost well casing and a heating element that is electrically isolated from the casing but disposed within it or in an adjacent casing but within the same borehole. Each of the two heating components is powered by a separate power source.