Session: 05-03: Concentrating Solar Power I: Receiver Applications

Paper Number: 131453

131453 - Multi-Flow Falling Particle Receiver Modeling 

Abstract: 

Generation 3 Concentrating Solar Power systems feature a solid particle heat transfer and storage medium to reduce the levelized cost of electricity production in concentrating solar power systems to the Solar Energy Technology Office goal of 0.05 $/kWh. Particle-based systems utilize a falling particle receiver which is composed an open receiver cavity through which the particles are flowed as curtain. The curtain is directly irradiated with the solar flux which is absorbed by the particles as they fall through the receiver. Particle receiver performance is highly dependent on curtain opacity (which is affected by particle curtain mass flow rate), particle average particle temperature, and ambient weather conditions such as wind. This study presents a novel free-falling particle receiver design which is consists of three individually controlled valves to supply the particle curtain to the receiver. Typically, one valve, consisting of a slide gate and an actuator, is used to create a uniform mass flow rate curtain. Particles within a uniform mass flow rate curtain are hottest at the center of the curtain due to the non-uniform flux distribution resulting in increased radiative and advective losses. Accordingly, lower flux levels at the periphery of the curtain result in lower temperature particles. The 3-valve-design was created to increase the efficiency of the solar receiver and increase the opacity of the particle curtain in the most critical regions to prevent back wall overheating. The outer two valves will have a lower mass flow rate which will more uniformly heat the particle curtain. A 1-d mathematical model of the falling particle receiver created in Engineering equation solver (EES) was adapted for 2-d analysis and used to optimize the efficiency and performance of falling particle receiver by adjusting the mass flow rate in each curtain section. The model considers energy, mass, and momentum balance equations in discretized sections of the particle curtain to calculate the particle outlet temperature and receiver back wall temperature as a function of incident flux.  The aim of this study is to find the optimal mass flow rate in each of the particle curtain generating valves as well as the mass flow rates of the two outer valves to increase receiver performance and to assess receiver back wall temperature with varying input flux conditions. The model will be implemented in a particle-based techno economic models to assess the effect the novel receiver has on plant performance, levelized cost of electricity, and receiver back wall material thermal cycling.  

Presenting Author: Ahmed Mohamed The University of New Mexico

Presenting Author Biography: Ahmed Mohamed
BA in Mechanical Engineering
PHD student, University of New Mexico
Mechanical engineering department

Authors:

Ahmed Mohamed The University of New Mexico
Gowtham Mohan University of Houston
Peter Vorobieff The University of New Mexico
Nathan Schroeder Sandia National Labs