Research On Heat Transfer Fluid Performance Of Solid Particle Solar Receiver

The solid particle solar receiver(SPSR)using solid particles as the heat transfer medium can reach a higher operating temperature,thereby obtaining a more considerable system efficiency.The research on the SPSR has been a hot topic in this field,but the research on solid particles is not sufficient.The purpose of this paper is to carry out the above research on the solid particles in the SPSR.In this paper,the basic characterization experiments of 18 kinds of solid particles are carried out through a variety of experimental methods.Combined with the cost of granular materials and comprehensive performance,silicon carbide particles and quartz sand particles are selected to construct the full spectrum particle system.In the experiment,the spectral absorptivity of the mixed particle system is measured.The results show that the optical performance of the particle system is better than that of the original single quartz sand particle.The higher the proportion of SiC,the higher the solar spectral absorptivity of the particle system.The influence of the spectral absorptivity of the mixed particles on the steady-state thermal efficiency of the receiver was obtained by calculation.The steady-state thermal efficiency of the receiver increases with the increase of the spectral absorptivity of the particle system.In addition,in the case of the same energy output,the change of mass flow rate under different ratios is calculated,and it is found that the mass flow rate decreases with the increase of material absorption.The material cost of the particle system is further calculated by this value.When the mass ratio of quartz sand to silicon carbide is about 50:0 to 40:10,the material cost is the best.When the mass ratio of quartz sand to silicon carbide is 42:8,the material cost of particle system is 0.03777 $/s,which means that the material cost of this point is less under the same output energy.When the mass ratio of quartz sand and silicon carbide is 42:8,the absorptivity of particle system is 73.51%,34.79%higher than 49:1,only 14.58%lower than 1:49,the steady-state thermal efficiency of heat receiver is 68.68%,32.36%higher than 49:1,only 12.43%lower than 1:49,and the material cost of particle system is reduced by 0.05039$/s,The results show that the comprehensive performance of granular materials is very competitive.In addition,with the change of the price of granular materials,the location of the best point can be further predicted.When the price of quartz sand increases or the price of silicon carbide decreases,the range of the best point moves to the right.In extreme cases,the comprehensive performance of single component silicon carbide particles is better;When the price of quartz sand decreases or the price of silicon carbide increases,the best range moves to the left.In extreme cases,the comprehensive performance of single component quartz sand is better,which means that even if the mass flow rate of single component quartz sand is large,it can also achieve the same output energy because of its great price advantage.This shows that when choosing the solid particle material in the SPSR,we should not blindly pursue the performance of the material and ignore the influence of the material cost,so we should further comprehensive analyse and consideration.