The European Southern Observatory (ESO) has chosen INTARCON to equip the four auxiliary telescopes of the VLTI at the Paranal observatory in Chile. INTARCON glycol plants produce glycol water at minus 25°C during the day to cool the telescope systems during night-time observation.

Glycol chillers

INTARCON glycol chillers are designed for ultra-quiet operation, equipped with hermetic Maneurop compressors and condensers sized to operate at 2800 m altitude. Their bodywork is designed to withstand inclement weather and to be coupled to the telescope’s mobile structure; the electrical and control panel has been adapted to be coupled to the telescope’s cooling module.

The refrigeration module

Every auxiliary telescope has a cooling module (LCM) that supplies refrigerant to the electronics, motors and optical systems. The cooling module contains a cold accumulator in phase change materials (PCMs). The phase change materials use the latent heat of fusion to absorb the heat energy dissipated inside the telescope.

The glycol plants operate during the day to accumulate cold in the PCM tank of the refrigeration module. It is not possible to operate the glycol plants during the night because the convention of condensing air would affect the quality of observation. So the energy accumulated during the day is used during the night.

European Southern Observatory VLTI telescope

The VLTI telescope is the most advanced optical instrument in the world today. It is composed of four main telescopes with a primary mirror of 8.2 metres in diameter plus four mobile auxiliary telescopes of 1.8 metres in diameter. The auxiliary telescopes are moved precisely from place to place around the VLT platform and from their positions the light beams are transported to the same focal point through a complex system of mirrors and underground tunnels.

Sigilus chillers are among the quietest of their size on the market. The cold production generated allows the telescope to be cooled 24 hours a day.