Method for installing geothermal heat exchanger
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Solution Overview
Problem
The installation of geothermal heat exchangers typically requires delaying construction operations and risks debris entering the tubes, as they need to be installed after excavation to avoid interference and debris obstruction, which complicates the process.
Innovation Solution
A method involving boring a borehole, inserting and securing a geothermal heat exchanger, temporarily sealing it, cutting above the uppermost seal, and removing the above-seal cut portions to allow excavation, with optional testing before sealing and connection to supply/return conduits, using specialized tools like pipe cutting tools for precise cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the geothermal heat exchanger is installed after excavation completion, then debris obstruction risk is reduced, but construction operations are delayed
Solution Approach 1:
The heat exchanger is installed in the borehole before excavation of the surrounding site begins. This preliminary installation allows the exchanger to be in place and secured while the site is still intact, eliminating the need to wait for excavation completion before installing the heat exchanger.
Solution Approach 2:
The installation process is divided into distinct phases: first installing and securing the heat exchanger in the borehole, then excavating the surrounding site, and finally removing the excess heat exchanger portion above ground. This segmentation allows construction operations to proceed without waiting for complete excavation while still protecting against debris obstruction through temporary sealing.
2Productivity
If the geothermal heat exchanger is installed before excavation, then construction operations can proceed without delay, but debris may enter the tubes and obstruct fluid flow
Solution Approach 1:
A temporary seal is introduced as an intermediary element between the heat exchanger and the excavation environment. This seal prevents debris from the excavation zone from entering the heat exchanger tubes while allowing the heat exchanger to be installed and secured before excavation begins.
Solution Approach 2:
The portion of the heat exchanger that extends above the ground after excavation is removed. This extraction eliminates the part of the heat exchanger that would be exposed to debris during excavation, while the sealed portion remaining in the ground continues to function without contamination risk.
3Ease of manufacture
If the heat exchanger is installed and left in place through excavation, then installation is simpler, but excavation machinery may damage the heat exchanger
Solution Approach 1:
The heat exchanger is divided into two segments: a protected portion that remains in the borehole and is sealed to prevent debris entry, and an excess portion that extends above ground and is removed after excavation. This segmentation prevents excavation machinery from damaging the functional portion of the heat exchanger while allowing simple installation of the entire length initially.
Solution Approach 2:
The excess portion of the heat exchanger that would be in the path of excavation machinery is removed after excavation completes. This extraction eliminates the conflict between excavation operations and heat exchanger protection, while the sealed portion remaining in the ground maintains structural integrity and continues to function.
Data Source
Figure 1A
Figure 1B
Figure 1Ba
AI summary
A borehole is bored to a borehole target depth in a site and a geothermal heat exchanger is inserted into and then secured in the borehole at the desired depth. Once the heat exchanger has been secured in the borehole, the heat exchanger has a closed distal end and an open proximal end and has at least one fluid path between the closed distal end and the open proximal end, with installation fluid disposed in the fluid path(s). After securing the heat exchanger in the borehole and before excavation of a portion of the site immediately surrounding the borehole, the heat exchanger is temporarily sealed by installing, through the open proximal end, at least one respective internal seal in each fluid path. For each fluid path, the internal seal(s) will be disposed below a respective notional subgrade depth and excavation of the site immediately surrounding the borehole can proceed.