Concentric Pipe Geothermal Well Head for Reduced Borehole Depth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional U-pipe geothermal heat exchanger systems suffer from inefficiencies due to close proximity of supply and return flow portions, leading to unwanted heat exchange and the need for deep, costly boreholes, which are impractical for many installations and increase material and maintenance costs.
Innovation Solution
A concentric pipe configuration with a larger diameter outer pipe and smaller diameter inner pipe is used, allowing for a greater surface area and contact time with the earth, reducing the required borehole length by 40-50% and enabling shallower, angled boreholes, and utilizing high-density polyethylene for durable and corrosion-resistant components with field-assembled well heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a U-shaped pipe configuration is used with supply and return flow portions placed close together to reduce borehole diameter, then material costs are reduced, but heat exchange efficiency deteriorates due to unwanted heat transfer between adjacent pipes
Solution Approach 1:
The inner pipe is nested within the outer pipe in a concentric arrangement, with the annular space between them serving as the heat exchange medium pathway. This nesting configuration allows the supply and return flow portions to be thermally isolated while maintaining a compact borehole footprint, thereby improving heat exchange efficiency without increasing device complexity
Solution Approach 2:
The return flow portion is extracted from the conventional U-shaped configuration and repositioned as a separate inner pipe concentric to the outer pipe. This separation eliminates the thermal interference between supply and return lines that plagues traditional U-pipe systems, resolving the contradiction between energy efficiency and configuration simplicity
2Loss of energy
If the diameter of supply and return flow pipes is increased and they are placed farther apart to improve heat exchange efficiency, then thermal performance is improved, but borehole depth and drilling costs increase
Solution Approach 1:
By nesting the inner pipe within the outer pipe, the system achieves effective thermal isolation of supply and return flow portions without requiring increased borehole depth. The concentric arrangement maximizes the use of available borehole space, allowing larger effective pipe diameters for heat exchange while maintaining shallower borehole lengths compared to conventional separated pipe configurations
Solution Approach 2:
The system transitions from a planar, side-by-side pipe arrangement to a three-dimensional concentric configuration. This dimensional change allows the heat exchange surfaces to be positioned at different radial distances from the borehole center, effectively increasing the heat exchange area without proportionally increasing borehole depth
3Productivity
If conventional U-pipe systems are used with small diameter pipes placed close together, then installation simplicity is maintained, but the required borehole length increases leading to higher installation costs
Solution Approach 1:
The concentric nesting of pipes within a single borehole allows for more effective heat exchange per unit length of borehole. This configuration improves installation efficiency by reducing the total borehole length required compared to conventional U-pipe systems, while maintaining relative installation simplicity through standardized pipe assembly procedures
Solution Approach 2:
The system changes the geometric parameters of the heat exchange configuration by using concentric circular arrangement instead of linear U-shaped arrangement. This parameter change increases the effective heat exchange surface area per unit borehole length, thereby reducing the required borehole length and improving installation efficiency
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 concentric pipe system enhances thermal efficiency and reduces installation costs by allowing shallower boreholes, minimizing site disturbance, and eliminating the need for metallic components, thus improving the economic viability and reducing the carbon footprint of geothermal heat pump systems.
Implementation Method 1
heat is exchanged between the fluid and the surrounding ground mass
Data Source
AI summary
A concentric pipe geothermal heat exchanger well head is described. The well head may include a riser pipe having an outer pipe and an inner core pipe, wherein an inner heat exchanger pipe is coupled to the inner core pipe, a reducer coupled to an outer heat exchanger pipe on one side and coupled to the outer pipe on a second opposite side to conduct fluid between the outer heat exchanger pipe and the outer pipe, a flow pipe parallel to and biaxial with the riser pipe configured to be coupled to a geothermal heat pump, and an elbow coupled to the outer pipe to couple fluid between the outer pipe and the well head pipe.