U-Shaped Geothermal Probe Assembly for Lower Material Use
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Solution Overview
Problem
Conventional methods for producing U-shaped geothermal probes from coilable plastic-coated copper pipe face material and cost inefficiencies due to the need for thick walls and large diameters to prevent damage during insertion, which can lead to thermal issues and increased material usage.
Innovation Solution
The method involves winding two plastic-coated copper tubes onto a drum to the desired length, stripping the ends, connecting a thicker U-shaped copper piece, and encasing it in a mold with a plastic melt to create a U-shaped probe section, allowing for reduced pipe cross-sections and material savings, with the U-bend being made of copper alloy for enhanced wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pipe wall thickness and diameter are increased to prevent damage during insertion, then the mechanical strength and damage resistance are improved, but the material consumption and cost increase
Solution Approach 1:
The pipe system is divided into two segments: a thin-walled coilable section for heat transfer and a thick-walled U-shaped section for mechanical protection. This segmentation allows each part to be optimized for its specific function without compromising the other.
Solution Approach 2:
The pipe wall thickness is made non-uniform, with thicker walls specifically at the U-shaped bend area and thinner walls in the straight sections. This local quality optimization provides enhanced protection where needed while reducing material consumption in less critical areas.
2Reliability
If the pipe wall thickness is increased to avoid thermal damage, then the thermal protection is improved, but the heat transfer efficiency deteriorates
Solution Approach 1:
The pipe is segmented into thin-walled sections for optimal heat transfer and a thick-walled U-shaped section for mechanical protection during insertion. The thin-walled sections minimize thermal resistance while the thick section provides protection only where mechanically necessary.
Solution Approach 2:
The wall thickness is optimized locally: thin walls in heat transfer zones maximize thermal efficiency, while the U-shaped bend area has increased wall thickness to withstand insertion stresses without compromising overall thermal performance.
3Strength
If the pipe diameter is increased to prevent damage during insertion, then the mechanical strength is improved, but the material cost and flow requirements increase
Solution Approach 1:
The pipe system uses different diameters for different sections: standard diameter for coilable sections and increased diameter only for the U-shaped bend area. This provides mechanical strength where needed while minimizing material consumption and flow requirements in the majority of the pipe length.
Solution Approach 2:
The pipe diameter is optimized locally with increased diameter specifically at the U-shaped section to withstand insertion forces, while the straight sections maintain standard diameter to minimize material use and heat transfer medium consumption.
4Shape
If the PE jacket is stretched during U-shape bending, then the U-shape formation is achieved, but cracks may form leading to thermal damage
Solution Approach 1:
The PE coating is removed from the U-shaped bend area before forming, isolating this section from the stretching stresses that would cause cracking. The coating is retained on the straight sections where it provides thermal protection without undergoing deformation.
Solution Approach 2:
The PE jacket is extracted (removed) from the U-shaped section prior to bending, eliminating the risk of cracking in this critical area. The coating is then reapplied or the section is protected differently after forming.
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 results in significant material and cost savings, enabling the use of pipes with diameters up to 50% smaller, improved heat transfer efficiency, and ensures a tight, durable connection, reducing flow-related wear and thermal damage.
Implementation Method 1
A plastic melt is then introduced or injected into the mold and the U-shaped tubular probe section is completely encased. A material connection is created between the plastic-coated pipe sections protruding into the mold cavity and the supplied melt.
Implementation Method 2
Geothermal probes consist of a pipe that is used to transfer the heat in the ground to the heat transfer medium in the pipe. The better the thermal conductivity of the pipe wall, the faster the heat is transferred.
Implementation Method 3
If the heat transfer medium is colder than the prevailing ground temperature, it absorbs heat from the ground.
Data Source
Figure 1~2
AI summary
The method involves synchronously winding two plastic-coated copper tubes (8) over a drum. The two bare copper tube end sections (3) are comprised at the stripped free ends of the tubes. A U-shaped tubular geothermal probe is loaded into a casting mold (1) and completely enclosed in a pressure-tight manner, and the tube end sections are projected into a mold cavity of a tool such that a cohesive connection is made. The mold is opened after cooling, and the tube end sections are removed from the mold and the remaining end is rewound onto the drum.