Molten salt as heat transfer fluid for a 500 m2 dish concentrator

A study into the integration of a molten salt based thermal storage system with the ANU SG4 500 m2 dish solar concentrator was performed. Specifically, the objective was to research the behaviour of molten salt as a heat transfer fluid for the SG4 dish solar concentrator, including its receiver, auxiliary piping and accessories. A numerical model was developed to analyse the heat transfer at the receiver and also to obtain the hydraulic pressure losses and demand curve for the entire system. This case study was restricted to a receiver position of 90º, or facing downwards, as this position requires the highest molten salt flow, and hence gives a maximum sizing for system components. The results indicate that the molten salt temperature profile inside the receiver is dominated by the solar irradiance profile over the cavity surface; with the heat exchange by radiation, conduction and natural convection having a lesser effect. Existing pipework, receiver tubes and rotary joints from the SG4 dish would need to be resized for reduced pressure drops. However, this initial investigation suggests that the use of molten salt as a heat transfer fluid for the ANU 500 m2 dish is feasible, and warrants further investigation. 1