Cryotank Withdrawal Layout With External Heat Exchanger Recirculation
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Solution Overview
Problem
Existing cryogenic tanks face challenges with complex heat exchanger maintenance, increased risk of leaks, reduced inner tank size, and potential freezing due to heat exchangers being installed within the insulating vacuum, necessitating two different types of heat exchangers.
Innovation Solution
The cryogenic tank design features a withdrawal device with heat exchangers located outside the insulation space, utilizing coaxial pipes for the extraction and recirculation lines to ensure effective heat transfer and maintain temperatures above 90 K, allowing for simpler maintenance and larger inner tank capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heat exchangers are installed within the insulating vacuum, then heat transfer efficiency is improved, but maintenance difficulty increases and leak risk increases
Solution Approach 1:
The system is divided into two separate heat exchanger units: a first heat exchanger located inside the insulating vacuum for efficient heat transfer, and a second heat exchanger located outside the vacuum for maintenance and operational flexibility. This segmentation allows each unit to serve its specific function while being independently accessible.
Solution Approach 2:
A recirculation line acts as an intermediary medium, transporting cryogenic gas between the first heat exchanger (inside vacuum) and the second heat exchanger (outside vacuum). This intermediary enables heat transfer functionality to be distributed across different locations with different maintenance requirements.
2Use of energy by moving object
If heat exchangers are installed within the insulating vacuum, then heat transfer efficiency is improved, but the risk of leaks increases
Solution Approach 1:
The heat exchanger system is segmented into two parts: the first heat exchanger remains inside the vacuum for efficiency, while the second heat exchanger is positioned outside the vacuum where it is easily accessible for inspection and maintenance, thereby reducing overall system leak risk.
Solution Approach 2:
The second heat exchanger positioned outside the vacuum can be independently maintained and inspected without requiring vacuum system intervention, enabling self-service maintenance that reduces downtime and improves reliability.
3Use of energy by moving object
If heat exchangers are installed within the insulating vacuum, then heat transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The recirculation line merges the functions of transporting cryogenic gas from the first heat exchanger to the second heat exchanger and back to the inner tank. By combining these transport functions into a single integrated line, the piping system achieves simplicity despite the distributed heat exchanger configuration.
4Use of energy by moving object
If heat exchangers are installed within the insulating vacuum, then heat transfer efficiency is improved, but the inner tank volume is reduced
Solution Approach 1:
The second heat exchanger is extracted from the inner tank volume and positioned outside the vacuum insulation. This extraction frees up valuable inner tank space for increased medium storage capacity while maintaining the heat transfer efficiency provided by the first heat exchanger inside the vacuum.
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 design enhances enthalpy utilization of the recirculated gas stream, reduces the risk of freezing and leaks, and simplifies maintenance by placing heat exchangers in the air area, ensuring efficient pressure build-up and larger inner tank volume.
Implementation Method 1
a recirculation partial flow can be conveyed back into the inner tank via a recirculation line to heat the medium in the tank
Implementation Method 2
the medium is conveyed from the inner tank to a first heat exchanger located outside the inner tank via a withdrawal line in order to heat the hydrogen
Implementation Method 3
the extraction line and the recirculation line in the insulation space are configured in such a way that good thermal contact exists between the extraction line and the recirculation line
Data Source
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AI summary
A cryogenic tank comprising a withdrawal device for the medium stored in the cryogenic tank, in particular hydrogen, wherein the cryogenic tank comprises an inner tank (1) for receiving the medium, an outer container (2) surrounding the inner tank (1), and an insulation space (3) between the inner tank (1) and the outer container (2), wherein the withdrawal device comprises at least one withdrawal line (4), wherein the medium is conveyed through the withdrawal line (4) from the inner tank (1) to a first heat exchanger (5) arranged outside the inner tank (1), wherein after the first heat exchanger (5) a withdrawal partial flow is directed to a consumer (6) and a recirculation partial flow is directed back into the inner tank (1) via a recirculation line (7), wherein the first heat exchanger (5) is arranged outside the outer container (2), wherein the withdrawal line (4) and the recirculation line (7) are configured in the insulation space (3) such thatthat good thermal contact (8) exists between the extraction line (4) and the recirculation line (7).