Speakers
Description
As part of the energy transition, the off-shore wind power market is booming with many very large-scale projects emerging or already in operation in Europe, Asia and America. Wind farms are commonly made up of several dozen turbines, the power of which has steadily increased in recent years, now exceeding more than 10 MW each, or soon even beyond.
Installed more than 150 meters above the waves, the nacelles housing the electric generators nowaday weigh more than 400 tonnes. This includes in particular the tens of tons of rare earths used in electromagnets that operate at room temperature.
By cooling the electromagnets located in stators or rotors down to cryogenic temperatures, a superconducting state can be achieved, where electrical conductors do not oppose any resistance anymore. The weight of the generator and therefore that of nacelles might then be reduced by several dozen tons, while the mass of necessary rare earths might be reduced by two orders of magnitude.
This poster presents an innovative cryocooling concept using turbomachines that is able to provide about 1 kW of cooling power at 20 Kelvin, up to 4.8 kW at 65 K, enough for cooling a 10 MW-scale wind turbine generator, or any other type of superconducting application. Other versions will operate at 4 K. It is based on Air Liquide’s extensive experience on the mature reverse turbo-Brayton refrigeration technology (from the International Space Station to LNG ship carriers) and on large superconducting systems for scientific instruments (CERN-LHC, ITER, SLAC, etc…).
A compact, hermetic and extremely reliable system, this standalone cooler is composed of a few small turbomachines and heat exchangers mounted on a unique plate. An internal manifold distributes the cold gas to the various magnets using closed loops. The complete system can cool down either stators or be mounted onto a direct drive rotor to rotate with it.
Superconductivity is a mature technology that has recently been demonstrated on the field for wind turbines. With our well suited cryocooler, it will become clear to wind turbine OEMs this will play a critical role, given the numerous wind farms to be built in the near future. This cooler will also address superconducting power transmission cables working up to 65 K or any other type of superconducting application. Notice this highly flexible cooler can also provide cooling power at temperature lower than 20 K with a reduced efficiency.
This makes it a very versatile, flexible and compact cooling system featuring the reliability we can expect from an industrial equipment.
