Challenge: The mismatch in electricity demand and production from renewable resources leads to a reduced utilization of renewable electricity sources. This challenge can be met by implementing thermal energy storage units into the grid that can store cheap electricity from renewables as heat and then convert that heat to electricity using conventional steam cycles. In order to achieve relatively high round trip efficiency, heat must be stored above 500 °C, heat transfer between the heated air and rocks must be efficient and losses during storage must be as low as possible.
Idea/solution: We have constructed a flexible 1.5 m3 rock storage unit at the DTU Risø campus. We are continuously testing different rock materials and bed configurations in order to improve overall efficiency.
Figure 1. Photo of the rock bed (left) and the measured temperature distribution in the bed during and experiment (right).
Your task: investigate techniques to improve the rock bed storage efficiency. This can include running experiments on the existing setup using different rock materials or sizes, redesigning the system configuration and performing detailed modelling of the system. New results will be compared to previously obtained measurements to assess the improvement to system performance. The economic impact of improved results can also be analyzed.
Interested students should contact senior researcher Kurt Engelbrecht (kuen@dtu.dk)