Storing energy in gravel and steel

Challenge

The energy store in this project was originally intended to be tested exclusively with granite chips. In order to find the shard size that provides the best possible compromise between low pressure loss and the ability to absorb heat, a particle size experiment must be prepared on both sides of the optimum, so as to be sure that the optimum is within the experimental range.

For this reason, supplemental experiments will be run with gravel, whose grain size is expected to produce a pressure loss greater than that which is desired, but with an effective thermal transition between the gravel and air.

The latter is due to its large surface area relative to its volume, which is characteristic of small particles. An additional experiment will be conducted in which the test material will be replaced with steel. Per unit volume, steel can contain upwards of 50% more energy per degree increase in temperature.

Solution idea

This project will investigate both temperature gradients and pressure losses in the store when the storage material is changed from granite to gravel and steel.