Solar thermal energy

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Student project proposals 2016

We invite master thesis students to take part in our joint research efforts with African universities on the development and testing of concentrating solar heat collectors with integrated heat storage units. The primary application is for food preparation (cooking, baking, frying). In Ethiopia, an important moticvation is the frying of the injera bread. The work will be made at NTNU, possibly with visits to our collaboration partners during the spring 2016.


Harald Andreassen did parts of his master work at the University of Mekelle, Ethiopia (2012)

Master thesis work within our solar thermal research activites can be either experimental or computational (simulation or model programming). Current activities focus on oil based systems and direct illumination of heat heat storage units.

Experimental

  • New frying pan. We need to make a new frying pan, now with heat transfer from either the focal point of a concentrator or from a heat storage, using a heat pipe. The pan shall be demonstrated for baking of the Ethiopian bread injera, and integrated with a heat collector at the University of Mekelle.
  • Direct illumination of a latent heat storage. We have used nitrates as Phase Change Materials, as they have melting temperatures which are in a suitavel range for frying. A new storage must now be deisgned (e.g. from a Scheffler reflector), allowing for solar heating at one side and heat extraction from a top plate. The storage can be tested using our indoor solar simulator.
  • Oil based system. Thermal stratification can be exploited in solar heat storage systems. A system with oil and rock bed is to be tested, including methods for scale up to larger systems. A new low cost oil pump also needs to be made and tested. The concept will be applied for deep frying systems in Uganda.
  • Computational

  • Dynamic model for an oil system. One student is already working with 1D models. An extension is needed for the particular case of deep frying, in collaboratio with our friends at Makerere University.
  • Coupling of a Ray Tracer with a heat conduction solver. A ray tracer can provide the heat flux distributio on an absorber. There are several program options for heat transfer simulations (Comsol multiphysics, ANSYS, Open Foam). A coupling of the two would be useful. One particular case for us is a side illuminated storage.
  • Heat transfer in molten salt. The conductivity of Nitrate salts is very low. One question is then how the heat transfer will be in systems where the salt is melting at the heat transfer surfaces, where natural convection can be induced. COMSOL Multiphysics has been applied for heat transfer analysis in melting systems before. This can be attempted in a master thesis work, now with application to our storage systems.
  • Ray tracing. Our ray tracer has proved to be useful in our work. The ray tracer can be further extended to cover a broader range of relfector geomtries, including Compound Parabolic Reflectors.