Lab-scale Experimentation and CFD Modeling of a Small Particle Heat Exchange Receiver

Abstract

Concentrating solar power currently relies on high temperature central receivers that utilize liquid cooling and operate in power steam cycles. However, highly efficient central receivers are being designed to operate at higher temperatures in a gas turbine power cycle. To address this, San Diego State University's (SDSU) Combustion and Solar Energy Laboratory is experimenting with a lab-scale Small Particle Heat Exchange Receiver (SPHER) in order to understand performance and develop experience for designing and operating a full-scale 5 MW design. The full-scale design will be tested at the National Solar Thermal Test Facility at Sandia National Laboratories as part of the Department of Energy SunShot Initiative grant. The SPHER relies on carbon nanoparticles as an absorption medium and air as a working fluid. The carbon particles are generated onsite by the Carbon Particle Generator (CPG) and are mixed with dilution air prior to entering the SPHER. Lab scale on-sun testing is carried out with a 15kWe solar simulator. The lab scale experimental goal is to achieve an outlet flow of 650°C at 5bar absolute operating pressure. To model the performance of the SPHER, CFD analysis is being used for comparison to lab scale testing. The lab scale SPHER is being modeled in ANSYS Fluent with coupled codes for oxidation and radiation input. In this paper, we present results of testing the lab-scale receiver and compare the measured outlet temperatures to predictions from the computer model. Finally, correlations are drawn for future experimenation and feasibility.