Cryogenic Cooling Head Layout With External Counterflow Heat Exchanger
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Solution Overview
Problem
Existing cooling devices for semi-cryogenic or cryogenic temperatures require large vacuum chambers, leading to inefficiencies and economic unviability, especially for high-performance applications, due to increased size and heat losses associated with flexible gas supply lines.
Innovation Solution
The cooling head is placed in a vacuum chamber connected via flexible, thermally insulated lines to a counterflow heat exchanger located outside the chamber, allowing coolant liquefaction outside the vacuum chamber, with the heat exchanger and lines insulated using materials like expanded polystyrene or vacuum insulation panels to minimize losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the counterflow heat exchanger and cooling head are combined into one structural unit and arranged in a vacuum chamber, then the cooling device can operate efficiently at semi-cryogenic or cryogenic temperatures, but the vacuum chamber becomes very large and the device becomes economically unviable for high-performance applications
Solution Approach 1:
The cooling device is divided into separate functional units: the counterflow heat exchanger is separated from the cooling head and vacuum chamber. The heat exchanger operates independently outside the vacuum chamber, while only the compact cooling head is placed inside the vacuum chamber with the object to be cooled. This segmentation allows the vacuum chamber volume to be dramatically reduced while maintaining cooling efficiency.
Solution Approach 2:
The counterflow heat exchanger is extracted from the vacuum chamber and positioned outside. This extraction removes the large heat exchanger volume from the vacuum chamber, allowing the chamber to be sized only for the cooling head and object, thereby solving the volume contradiction.
2Ease of operation
If flexible gas supply lines are used to transport coolant from room temperature to semi-cryogenic or cryogenic temperatures in the vacuum chamber, then the lines do not require insulation, but heat losses occur and icing and condensation formation problems arise
Solution Approach 1:
The coolant is pre-cooled and pre-liquefied in the counterflow heat exchanger before being transported to the cooling head. This preliminary cooling action ensures that the coolant arrives at the vacuum chamber already at the required semi-cryogenic or cryogenic temperature, eliminating heat loss issues during transport and preventing icing and condensation.
3Productivity
If the cooling capacity is increased in existing devices with the heat exchanger in the vacuum chamber, then higher cooling powers are achieved, but the size of the heat exchanger and vacuum chamber increase significantly
Solution Approach 1:
By separating the heat exchanger from the vacuum chamber, the cooling capacity can be increased by enlarging the heat exchanger outside the chamber without affecting the chamber volume. The cooling head inside the vacuum chamber remains compact, allowing high cooling capacities (e.g., 200W at 140K) to be achieved while maintaining a small vacuum chamber volume suitable for high-performance applications.
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 achieves a tenfold increase in cooling capacity while reducing the volume by 30 times, ensuring efficient and space-saving cooling performance with minimal thermal losses, suitable for high-power applications like laser amplifiers and analytical chemistry.
Implementation Method 1
a counterflow heat exchanger (7) comprising a supply line (8) and a return line (9), which are arranged in such a way that the compressed coolant in the supply line (8) can be liquefied while heating the expanded coolant flowing through the return line (9)
Implementation Method 2
a cooling head (11) connected to the return line (9) and through which the coolant flows, in which the coolant evaporates
Implementation Method 3
The heat exchanger can be insulated, for example, with the help of its own vacuum chamber with a vacuum pump
Data Source
Figure 1
Figure 2~3
AI summary
In a cooling apparatus with a closed cooling circuit for cooling objects to semi-cryogenic or cryogenic temperatures of 230K to 80K, the cooling apparatus comprising a compressor for compressing a coolant, to which compressor the coolant is supplied in a gaseous state and from which the coolant emerges in a compressed gaseous state, an after-cooler which is connected downstream of the compressor and from which most of the coolant emerges in gaseous form, a counterflow heat exchanger comprising a feed line and a return line, which are arranged in such a manner that the compressed coolant is liquefied in the feed line by the expanded coolant flowing through the return line being heated, and a cooling head which is connected to the feed line and the return line and through which the coolant flows and in which the coolant is evaporated, the cooling head (11) is arranged in a vacuum chamber (16) which can be connected to a negative pressure source and is connected to the feed line and the return line (8, 9) of the counterflow heat exchanger (7) via flexible connecting lines (13, 14).