/// Innovative Cooling Concepts
The permanent power density as well as the material costs depend critically on the cooling of the electrostatic machine. With a good design of the electrostatic machine and a water tissue cooling it´s possible to achieve a permanent power density of 5kW/kg.
We use as well the direct oil cooling of the winding heads. This represents a meaningful solution, as the oil will also be used for the gear lubrication. In the measurements it was possible to achieve more than a 4x Power loss with the additional use of Oil and Winding Head Cooling.
On most applications however, the numerous disadvantages of Oil cooling overweigh. Oil has clear worse cooling properties as Water/Glycol. Due to the fact that the windings of the electric machines can be flown around with oil, this leads to a better heat dissipation inside the machine. However, if we take the total expenses into consideration, the oil cooling is inferior to the water cooling at a system level.
The optimal solution to this problem is an integrated cooling concept, which has been used on the SC41. The cooling medium is in this case Water/Glycol. With the usage of complete isolated cooling canals on the groove, extrem permanent power can be achieved.
Through the low copper temperatures, the losses in several applications with middle and high load profiles can compensate the copper cross section losses, whereby the cycle efficiency raises.