Heuser, J. M.

Petagna, P.

Sanchez, J.

Schmidt, C. J.

Schmidt, H. R.

Verlaat, B.

Zwalinski, L.

GSI Repository

TRACI-XL, the test cooling system for the CBM Silicon Tracking System∗J. Sa´nchez1, J. M. Heuser1, C. J. Schmidt1, P. Petagna2, B. Verlaat2, L. Zwalinski2, and H. R. Schmidt31GSI, Darmstadt, Germany; 2CERN, Geneva, Switzerland; 3Eberhard Karls University, Tu¨bingen, GermanyAn evaporative bi-phase cooling system based on CO2has been chosen as the best option to extract the heatproduced by the read-out electronics in the CBM Sili-con Tracking System. In the framework of the EU-FP7project CRISP, the system TRACI (Transportable Refrig-eration Apparatus for CO2 Investigation), developed atNIKHEF/CERN to provide support to the ATLAS andLHCb experiments, is being upgraded at GSI from 100 Wto 1 kW cooling power. This system TRACI-XL will beused as a testing device for the CBM application.I-2PACL concept applied to TRACI-XLThe I-2PACL principle (Integrated 2 Phase Accumula-tor Controlled Loop) was created as simplification of the2PACL systems by using the CO2 line to condensate thegas inside the accumulator instead of using a branched linederived from the condensing unit. Therefore the control isreduced to one cartridge heater controlled by PLC SiemensSimatic S7-1200. The size of the control unit is decreasedand it allows a wider range of possible operating tempera-tures from -30◦ C up to room temperature.Figure 1: Process diagram of TRACI-XL.This range is obtained due to the implementation ofa condensing unit equipped with a Bitzer 2DC-3.F1YVarispeed compressor and Swep heat exchanger with a sys-tem performance as follows:• at 30 Hz; Q0 = 0,55 kW, T0 =-45◦ C,Tsuction = -30◦ C, Tc = +35◦ C, Tsub = 3 K, R404a.• at 87 Hz; Q0 = 1.59 kW, T0 = -45◦ C,Tsuction = -30◦ C, Tc = +35◦ C, Tsub = 3 K, R404a.System operationA LEWA membrane pump with remote head design,as innovation to avoid the addition of residual heat in the∗Supported by EU-FP7 CRISP.coolant, transports sub-cooled CO2 to the evaporator in thethermal box (1-2-3-4-5 in Fig. ??). The CO 2 is heated upto the right evaporation temperature by a heat ex-changeproduced inside an inner hose with the returning CO2 line(6-7). Due to the pulses generated by the metering pumpthe installation of a pulsation dampener is needed.Figure 2: Cycle in Enthalpy-Pressure diagram for R744.(a) Full model. (b) CO2 Line.Figure 3: CAD model with CO2 line detail.The heat generated in the read-out electronics is ab-sorbed and extracted by the evaporator capillaries inside thethermal box (5-6). The return line (8-1) contains a bi-phasemixture which is liquefied by the condensing unit namedpreviously below the operating temperature. By controllingthe pressure inside an accumulator the evaporation temper-ature can be fixed. This vessel contains two-phase CO2 incontact (see Fig. ??).References[1] Verlaat, B., International Conference of Refrigeration 2007,Beijing, China, ICR07-B2-1565PHN-NQM-EXP-25 GSI SCIENTIFIC REPORT 201254

TRACI-XL, the test cooling system for the CBM Silicon Tracking System

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TRACI-XL, the test cooling system for the CBM Silicon Tracking System

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