Helium Liquefaction at TU Darmstadt
The central helium plant of the TU Darmstadt exists for over fifty years and is traditionally located at the Institut for Solid-State Physics. After several predecessor plants of ADL, Phillips and Linde the institute operates a condensor TCF 20 of the company Linde since 1995.
From cost reasons the liquefier is operated for precooling exclusively with liquid nitrogen (liquid nitrogen, LN2). The central liquefier supplies ten working groups in Darmstadt as well as two working groups at the University of Frankfurt. The liquefaction costs in the year 2007 for the institutes of the TUD amounted to 0.073€ per litre liquid helium. The TUD pays the electricity costs of at present 0,60€/l as well as 0,44€/l for LN2. For the University of Frankfurt these costs are proportionately billed.
The liquefaction capacity, indicated in spent litres in transportation cans, amounted to 38000 litres in the year 2008. A liquefaction capacity of 80.000 litres per year was even reached before. The helium supply of the plant amounts to 7,000 litres, which is circulating as liquid helium. The gas losses of the consumers amount to approx. 1.5 to 6.0%.
The evaporating helium of the central institutes is returned over 4km pipings to the back compression plant. The more distant institutes and the University of Frankfurt return their helium gas compressed in gas bottle bundles.
- Liquefier TCF 20 with a liquefaction capacity of 27 respectively 54 litres per hour
- Condenser DS 170 with a power drain of 100 kW
- Oil separation and oil adsorbent
- Gas adjustment station and gas dryer
- Storage tanks for 2600 respectively 1100 litres of liquid helium
- Clean gas storage tank for 5m3
- LN2-tank for 11m3
- 2 gas balloons with a volume of 10 m3 each
- 3 back compressors S&S 40 m3 per hour each
- 5 high pressure tanks with together 17 m3
- 2 bundle stations with together 12 gas bottle bundles
- 2 feeding stations for filling and emptying bottles
- Clean gas feeding