European Research Project VACI on Vacuum Insulations has been Finished Successfully - page 2

continued: "Work Performed and End Results"
At va-Q-tec manufacturing facilities for producing cylindrical vacuum insulations were established. Fig. 2 shows a variety of circular vacuum panels produced by va-Q-tec for the test site at KAEFER. Foiltec developed more complex forms with doubly curved shapes and established adequate manufacturing procedures. Foiltec could demonstrate successfully that the manufacturing of vacuum insulated complex shapes e.g. pipe elbows or T-pieces is possible. An example is depicted in Fig.3. The art of obtaining the desired shape lies in highly precise calculations of the cutting of the core material, which subsequently leads to the exact shapes required.

KAEFER conceived and built an experimental equipment on which the vacuum insulation could be installed and tested under near-reality conditions. Part of the pipe circuit with installed vacuum panels is shown in Fig.4. The pipes were equipped with several layers of vacuum insulation manufactured by va-Q-tec and Foiltec. The pipe system could be cooled down to temperatures of liquid nitrogen. Two test series have been performed successfully at the test facility. Temperatures and heat fluxes were monitored during floating the pipes with cold nitrogen gas. Even under cryogenic conditions of -160 °C (temperature of liquified natural gas, LNG) it could be demonstrated that the insulation technique exhibited extremely low heat fluxes, thereby permitting a considerable reduction in insulation thickness. The objective of 60 mm instead of 160 mm conventional insulation was actually improved even further. No significant deterioration of the vacuum panels due to the very low temperatures was detected. Further tests of vacuum panel installation were performed by Prodak and BC-Contract.

The total thickness of the vacuum insulation of about 50 mm has the same insulation performance as a conventional polyurethane foam insulation of 160 mm thickness. Thus the overall diameter of an insulated DN200 pipe is reduced from 520 mm to 300 mm, the overall cross section even is reduced by a factor of three.
The extremely low thermal losses enable substantial savings in amounts of steel and space used in the construction of refrigeration units, both with regard to volume as well as height.
Evacuated pipe insulations for low temperatures including complex elements now almost are a market ready product. The developments of this project may also be used for other applications of vacuum panels as in buildings, refrigerators or cold boxes.

Achievements of the project to the state-of-the-art
It could be demonstrated that complex three-dimensional shapes of vacuum panels, which are necessary for the insulation of pipe systems, can be manufactured and handled. Core materials have been found, which can be integrated in vacuum panels in an easy way, lowering manufacturing costs. Furthermore, procedures for testing vacuum panels could be improved significantly. It is now possible to measure the gas transmission of high barrier films including aluminium foils within some days. Monitoring the quality of installed vacuum panels on site has been improved in such a way that it can be done routinely.

Impacts of the project on its industry and research sector
The results of the project also have a considerable impact on other application fields like insulations of freezers, buildings and temperature controlled transport boxes. Especially the improved methods for quality monitoring of high barrier films and vacuum panels now are already in use for all products manufactured at va-Q-tec. Improved production methods for vacuum panels also have been found. By lowering production costs these new methods may be used for a wide range of applications and open many new market areas. Further projects have already been planned, which include the new methods and the established research facilities.

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