Moving Bed Heat Exchanger for Solar Central Receiver Power Plants: A multi-phase model and parameter variations

Kurzfassung

Sensible solid media storage based on particulate materials is a promising concept for solar central receiver systems. The bulk material can be used as heat transfer and storage medium at high temperatures. A new heat exchanger concept based on the principles of a moving bed has been developed deploying a compact design, a good part-load behaviour and low parasitic loads. Numerical investigations applying a multiphase CFD approach are conducted in order to identify the determining factors on heat transfer. In a subsequent design study, the tube shape as well as the tube arrangement is varied in order to identify a design improving the thermal performance of the device. A circular tube geometry is found to be the most economic one compared to rhombs or ovals. A narrow tube arrangement taking into account the flow properties of the bulk offers a potentially higher thermal efficiency and an even more compact design of the heat exchanger.