Session: 06-03: Concentrated Solar Power II -- Power Block and Components

Paper Number: 130916

130916 - Performance Comparison of Water vs Supercritical Carbon Dioxide Operation for Custom Radial Vaned Pump 

Abstract: 

Canned motor pumps designed for use with liquid fluids can be utilized, with minor modifications, as a circulator in supercritical carbon dioxide (sCO₂) systems operating in thermodynamic regions where the density of sCO₂ is close to that of water (~820 kg/m³ – 950 kg/m³). The use of canned motor pump technology can accelerate the introduction of supercritical and transcritical sCO₂ systems for power generation in concentrating solar, nuclear, conventional fossil fuel energies, and waste heat recovery. A 1 MW thermal sCO₂ cooling loop is under construction at Sandia National Laboratories to support efforts under the Generation 3 Concentrating Solar Program’s Generation 3 Particle Pilot Plant (G3P3). This system will utilize a radial vaned canned-pump (Teikoku Model NCRV N7) that was designed for providing up to 900 feet head (~275 m) and flows up to 140 gallons per minute (~8.8 L/sec). This pump has been operated with both water and sCO₂ at two different frequencies (60 Hz and 73 Hz) with the aid of a Variable Frequency Drive (VFD). A simple test loop layout, consisting of a single recirculation loop with flow control capability, temperature and pressure instrumentation have been installed and commissioned. Volumetric flow measurement is achieved by using a Venturi flow meter which can do flow measurement for both liquid or gaseous fluids. Pressure measurements are achieved with ABB pressure transducers, to quantify pressure differential and absolute pressures in the system. Temperature measurements are done primarily with RTD (Resistance Temperature Detector) units, which typically have a higher accuracy than thermocouples and avoid potential for cold junction compensation issues. Cold commissioning was completed and the results and lessons learnt is covered in this paper. Operation of a closed face radial vane canned-pump, operating with a supercritical fluid at the design pressures required for high temperature sCO₂ power generation, is a relatively new engineering solution. Historically canned motor pumps have been used in many different harsh environmental applications however, the design operating pressure for this application is a novel feature of the pump. Performance characteristics of the pump like the pressure head produced, volumetric flow rates, and electrical power and current consumption are compared for the different fluids. This work presents a performance comparison between water and sCO₂ pump curves based on manufacturer estimates and shows measured curves to provide a comparison between estimated and operational curves for sCO₂ operation. An estimation to correct for the different fluid curves is presented. SAND2023-13577A

Presenting Author: Hendrik Frederik Laubscher Sandia National Laboratories

Presenting Author Biography: Henk Laubscher is a young and creative mechanical engineer with a strong practical background and a passion for sustainability. His field of expertise is solar thermal energy and he holds a master’s degree in mechanical engineering (thermal energy storage) that he obtained at Stellenbosch University, South Africa in 2017. He has industry experience in the construction and commissioning of a 100 MW CSP parabolic trough plant, which provides him with the insights of large system integration. He joined Sandia National Laboratories in April of 2019 and is currently working at the National Solar Thermal Test Facility (NSTTF) in Albuquerque, NM.

Authors:

Hendrik Frederik Laubscher Sandia National Laboratories
Luke Mclaughlin Sandia National Laboratories
Matthew Sandlin Sandia National Laboratories
Robert Crandell Sandia National Laboratories
John Maloney Teikoku USA Inc
Christian Halupa Teikoku USA Inc
Keith Yutzy K Yutzy Consulting, LLC