One research project of our group deals with the development and the optimization of the Rubber Heat engine. One part of this work is the optimization of the used elastomer and its chemical properties, the other side the mechanical construction and optimization.
For the goal of high torques one need to use more mass of polymer, resulting in higher forces on bearings, etc. Therefore a solid mechanical construction is required with fixed bearings and an adjustable extender wheel, the free wheel axle from the scheme above does not fullfill the requirements. The following picture shows the actual state of development without load (left) and with load (right).
Beside the construction with a water bath we try a second strategy: Heat supply and cooling realized via water streams. Therefore, a completly new construction is necessary that is shown in the following pictures.
In the picture on the left one can see the connections for the hot and the cold water stream, in the picture on the right the detailed construction of the inner and outer wheel is shown.
This new construction shows more power than the old construction, especially the cooling via water is more efficient. The supply of heat still has to improved, heating at one point via water stream is inferior compared to the more extended hoth water bath.