Design optimization of the phase change material integrated solar receiver: A numerical parametric study

Dish-Micro Gas Turbine (D-MGT) systems can be an effective way of power production (< 100 kW) in rural areas having limited access to electricity. In such no fuel assisted systems, the stability of the input thermal power to the MGT is an important concern as MGT is sensitive to the temperature variations caused by the natural fluctuation of the solar flux. To reduce this effect, a novel solar receiver has been proposed integrated with a Phase Change Material (PCM) for the short-term thermal energy storage. The proposed receiver is cylindrical shaped filled with PCM, with a conical cavity on the front surface and heat transfer fluid tubes immersed in the PCM. This paper deals with the investigation of the optimum design point of the proposed receiver based on the required input parameters of the MGT. The numerical simulations have been conducted using Computational Fluid Dynamic methods to pre-evaluate the effect of many controlling parameters on the temperature, PCM liquid fraction, pressure loss and outlet thermal power of the receiver. Surface-to-Surface (S2S) radiation model has been employed along with the ray-tracing model for the constant concentrated solar flux of 500 kW/m(2) on the receiver aperture surface. The influencing factors considered in this study include the high-temperature PCMs, receiver cavity dimensions, incident solar flux, hot wall thickness, tube diameter and the number of the tubes, pressure drop inside the tubes and the inlet mass flow rate. Results demonstrate the considerable effect of each variable on the receiver output parameters, and this leads to the identification of optimum design point. The result of the study offers valuable guidelines for the receiver development for further experimentation.