The European Southern Observatory (ESO) chose Intarcon to develope a new glycol chillers to equip the four VLTI auxiliary telescopes in the Paranal Observatory in Chile. These Intarcon units are able to supply continously chilled glycol water at 25 Celsius degrees below zero to cool the telescope detectors at night.
The glycol chillers have been designed for an ultra silent performance. Their condensers have been specialy sized to operate at 2800 m over the sea level. The metal shells of the refrigeration units have been designed to stand extreme weather conditions and to integrate onto the mobile telescope structure. The control board has also been designed to integrate with the telescope cooling system.
Each auxiliary telescope incorporates a liquid cooling module (LCM) providing liquid coolant to the electronic systems, motors and optical assemblies. The cooling module contains a cold storage tank with phase change materials (PCM). Phase change materials make use of latent heat to absorb the heat produced within the telescope.
The glycol chillers operate during the day to store cooling energy in the PCM tank. The chillers cannot operate during the night because convective aire from the condenser will negatively affect the observation quality. Thus, only the cooling energy stored during the day will be used in the night to refrigerate the telescope.
The VLTI Telescope
The Very Large Telescope Interferometer (VLTI) is the most advanced optical instrument in the world. It consists of a coherent combination of the four VLT Unit Telescopes and of the four moveable 1.8m Auxiliary Telescopes. The VLTI Auxiliary Telescopes (ATs) are mounted on tracks and can be placed at precisely defined “parking” observing positions on the observatory platform. From these positions, their light beams are fed into the same common focal point via a complex systems of reflecting mirrors in an underground system of tunnels.