SCARLETT

The test facility SCARLETT basically consists of heat exchangers, heating radiators, compressors, valves, pressure vessels, a data acquisition and a modular test section. This test section can be replaced at any time depending on the need for research.

Schematic of the SCARLETT setup © Flaig, IKE

As can be seen in the schematic, liquid CO₂ is stored in a pressure vessel, called storage vessel (1). CO₂ is first completely evaporated and then superheated up to 10 Kelvin by an electrical heated evaporator (2). After passing a droplet separator (3) where the last liquid drops are removed from the gas flow, the CO₂ is entering a piston-compressor (4). There the CO₂ is compressed leading to supercritical temperatures and pressures (> 73.8 bar). Thereafter, the supercritical CO₂ flows through a heat exchanger (5), where it is cooled or optionally heated to the desired testing temperature (conditioning) and then enters the test section - represented as a black box in the schematic. The test section offers a variety of experimental setups for basic research. After leaving the test section (5'), the CO₂ flows through a gas cooler (6) and is thereby cooled to ambient temperature. Then the CO₂ is expanded in an expansion valve (7) to subcritical pressure. The resulting CO₂ wet steam is completely liquefied in a condenser (8) and then passes into a second pressure vessel (Collecting vessel) (9), which is also used for hydraulic compensation and gas/liquid separation. With the help of a refrigerant transfer pump (10), liquid CO₂ flows back into the storage vessel and the circuit of the test facility is closed.

At the plant SCARLETT different experimental set-ups are planned. At all experiments supercritical CO₂ enters the test section at a defined temperature and a defined pressure. The design of the test sections is variable and depends on the aims of the investigation.

Planned studies at the testing facility are for example:

• Validation of CFD models for supercritical water
• Heat transfer in passive safety systems with supercritical CO₂
• Basic research and data generation for the qualification of compact heat exchangers with supercritical CO₂ in the sCO2-HeRo-Project
• Interaction of supercritical CO₂ with ceramics (materials research)

SCARLETT: operational test facility, September 2016 © Flaig, IKE

Until now several projects were carried out using the test facility SCARLETT, funded by the European Commission (EU) and the Gesellschaft für Reaktorsicherheit (GRS), Germany.

• sCO2-HeRo (EU) - www.sco2-hero.eu
• sCO2-FLEX (EU) -  www.sco2-flex.eu  
• sCO2-QA (GRS)