Cooling system for aircraft electric or electronic devices

A cooling system for cooling an electrical or electronic equipment on board an aircraft, the cooling system comprising a main closed circuit, the main closed circuit comprising:

• a pump to circulate a heat transfer medium through the main closed circuit;
• a main heat exchanger thermally coupled with the heat transfer medium;
• a secondary heat exchanger allowing direct thermal coupling of the heat transfer medium to air on the outside of the aircraft;
• a bypass valve located upstream from the secondary heat exchanger, allowing to block, at least partially, the circulation of the heat transfer medium towards the secondary heat exchanger;
• and
• a bypass duct connecting the bypass valve to a point on the main closed circuit downstream from the secondary heat exchanger to allow the heat transfer medium to bypass, at least partially, towards the main heat exchanger as a function of a control setting of the bypass valve.