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Research Staff

Learn more about the expertise and technical skills of concentrating solar power (CSP) research team and staff at the National Renewable Energy laboratory (NREL) by reading their biographical information. In addition to information on their research interests and education, you can check publications that they have authored, pulled from the NREL Publications Database and listed beginning with the most recent.

Photo of Mark Mehos

Mark Mehos

Thermal Systems Group Manager

M.S. Mechanical Engineering, University of California at Berkeley
B.S. Mechanical Engineering, University of Colorado

Mark joined NREL in 1986 and manages the Thermal Systems R&D group at NREL, which includes the Concentrating Solar Power (CSP) Program. Since 2001, he served as the CSP program manager.

Mark is the leader for the International Energy Agency's SolarPACES "Solar Thermal Electric Power Systems" task, which focuses on the development of international guidelines for modeling and acceptance testing of CSP systems. He has participated on and conducted analysis for several task forces, including New Mexico Governor Richardson's Concentrating Solar Power Task Force, the Solar Task Force for the WGA Clean and Diversified Energy Initiative, and more recently the U.S. Department of Energy's Solar Vision and Renewable Energy Futures studies. He is actively involved in the development of several new grid-integration studies investigating the interaction of CSP systems with thermal energy storage within the western U.S. interconnect. | 303-384-7458


Photo of Victor Castillo

Victor Castillo

Research Technician IV

A.S. Electronics Engineering Technology, ITT Technical Institute

Victor joined NREL in 2011. He designs, fabricates, and assembles prototype test facilities. Victor primarily works with the Concentrated Solar Power group but also works with several other research groups, including Commercial and Residential Buildings, Advanced Optical Materials, and Biofuels.

Victor is also responsible for material testing using the three Ultra Accelerated Weathering Systems located on the NREL mesa top testing facility.

Before coming to NREL, he spent several years in the research and development of fuel cell technology. | 303-384-7476

Photo of Greg Glatzmaier

Greg Glatzmaier

Senior Engineer II

Ph.D. Chemical Engineering, University of Colorado
B.A. Chemistry, St. Johns University

Greg originally joined NREL in 1987 and worked in the Solar Thermal Program until 1997. During this time, he demonstrated a new concentrating solar technology and initiated a multiyear collaboration with Coors Ceramics Company to develop a high-temperature materials synthesis process. He was awarded three patents for this work.

From 1997 to 2007, Greg operated an R&D small business in which he developed fluid compressor designs and feedback control mechanisms for space applications. This work was funded with several R&D grants from NASA and the U.S. Air Force. He was awarded one patent for this work.

In 2007, Greg rejoined NREL and the Concentrating Solar Power (CSP) team to work on systems analysis, novel heat-transfer fluids, and thermal-storage concepts for CSP technologies. He currently manages the advanced heat-transfer fluids and thermal-storage work at NREL. | 303-384-7470

Photo of Kaan Korkmaz

Kaan Korkmaz

Undergraduate Intern

B.S. (in progress) Mechanical Engineering, Colorado School of Mines

Kaan joined NREL in May 2015 as an undergraduate intern, and he is a member of the Advanced Materials team. His position includes performing optical and mechanical measurements of samples exposed to accelerated and outdoor environments. | 303-384-6419

Photo of Zhiwen Ma

Zhiwen Ma

Senior Engineer I

Ph.D. Mechanical Engineering, Georgia Institute of Technology
M.S. Thermal Engineering, Tsinghua University
B.S. Thermal Engineering, Tsinghua University

Zhiwen joined the Thermal Systems Group in 2009 to work in the field of Concentrating Solar Power (CSP). His experience includes combustion, fluidization, hydrogen and fuel cells, electronic thermal management and packaging, and gas turbines. He taught in the Department of Engineering Mechanics at Tsinghua University for 3 years, conducted multiphase flow research, and developed pyrometer techniques for measuring gas turbine temperatures. Beginning in 2001, he was a Test and Modeling Engineer in Fuel Cell Energy, and worked on molten carbonate fuel cell performance and life improvement for cost reduction. He was also involved in the Solid State Energy Conversion Alliance program, supporting the testing and modeling of solid-oxide fuel cell stacks and system design.

Zhiwen has published papers and a book chapter, and was awarded two patents in the areas of fuel cells and thermal fluids. Before joining NREL, he worked for GE Aviation on gas turbine flow and heat-transfer design. He works on system analysis, measuring the properties of heat-transfer fluids, and developing thermal-storage concepts for CSP technology. | 303-275-3784

Photo of Janna Martinek

Janna Martinek

Postdoctoral Researcher

Ph.D. Chemical Engineering, University of Colorado
M.S. Chemical Engineering, University of Colorado
B.S. Chemical Engineering, University of Colorado

Janna Martinek joined the Thermal Systems Group at NREL in 2012 as a postdoctoral researcher. Her work involves developing computational models to evaluate the performance of power tower receiver concepts. For her graduate work, Janna developed models coupling radiative transfer with heat transfer, mass transfer, and chemical reaction kinetics in order to analyze the performance and optimize the geometric configuration of a solar receiver used for high-temperature solar-thermal reaction processes. | 303-275-3779

Photo of Ty Neises

Ty Neises

Engineer II

M.S. Mechanical Engineering, University of Wisconsin-Madison
B.S. Mechanical Engineering, University of Wisconsin-Madison

Ty joined the Thermal Systems group at NREL in 2011. His work focuses on modeling and analyzing the thermal fluid performance of concentrating solar power (CSP) systems and components. His recent work includes researching supercritical carbon dioxide (sCO2) systems for CSP applications and supporting the design of a high-pressure power tower receiver. Ty also develops and supports models for the System Advisor Model. | 303-275-4537

Photo of Judy C. Netter

Judy C. Netter

Mechanical Engineer III

B.S. Engineering Technology, St. Cloud State University

Judy joined the NREL staff in 1994. Judy is part of the Concentrating Solar (CSP) team and is the primary contact and operator for NREL's High-Flux Solar Furnace, a 10kW solar concentrator. Her expertise involves the design and fabrication of prototype experimental equipment along with the programs and controls. CSP-related projects include the design of experiments and test equipment for characterizing solar collectors, concentrators, and receivers for parabolic troughs, on-sun tests for solar thermochemical reactions (primarily hydrogen production), and recently Solar Power Tower Receiver design. She has also designed multiple secondary concentrators for the Solar Furnace, along with cooling chambers and multiple accelerated weathering chambers for testing the degradation of polymer coatings.

Since joining NREL, Judy has been heavily involved with design and testing in a wide variety of areas, including the condensation of mixed working fluids for geothermal technology; lifetime durability testing of electrochromic windows, thin films, photovoltaic cells, and polymers; thermal management of power electronics as it relates to hybrid vehicles; photocatalysis; and building technologies. | 303-384-6258

Photo of Teri Spinuzzi

Teri Spinuzzi

Business Support

Teri joined the NREL staff in August 1995. She provides administrative support to the Thermal Systems Group in the Buildings and Thermal Systems Center. Before joining this group, she provided administrative support to the Employment Team in Human Resources, the Deployment Programs Office, and the Technology Transfer Office. Before coming to NREL, Teri provided many years of administrative support to various departments, such as Human Resources, Information Services, and Industrial Hygiene, at the Rocky Flats plant. | 303-384-7425

Photo of Robert Tirawat

Robert Tirawat

Research Technician III

M.S. (in progress) Material Science, Colorado School of Mines
B.S. Electrical Engineering Technology, Metropolitan State College

Robert joined NREL in 2008 as a student intern for the Advanced Materials team. He has since graduated and was hired as a research technician. Robert helps to develop low-cost, high-performance, high-reliability systems that use concentrated sunlight to generate power. Recently, Robert has been involved developing a high-efficiency solar selective absorber and anti-corrosion coatings. | 303-384-6360

Photo of Craig Turchi

Craig S. Turchi

Senior Engineer II

Ph.D. Chemical Engineering, North Carolina State University
B.S. Chemical Engineering, Texas A&M University

Craig originally joined NREL in 1990 working in the Solar Industrial Program on the detoxification of hazardous waste with solar ultraviolet light. He returned to NREL in 2008 after spending 10 years as a principal investigator and program leader with ADA Technologies, a technology development company in Littleton, Colorado. While at ADA, Craig served as a principal investigator for projects with the U.S. Environmental Protection Agency, National Institutes of Health, U.S. Department of Defense, U.S. Department of Energy, Electric Power Research Institute, and several private companies. As part of NREL's Thermal Systems team, Craig helps to develop and assess heat-transfer fluids, thermal-storage systems, and power conversion and integrated system concepts. Craig has contributed as task leader for the Concentrating Solar Power Program's Market Transformation activities, which includes technology-enabling issues such as solar resource assessment, cost estimation, land use, environmental impact, and grid integration and transmission. | 303-384-7565

Photo of Judith Vidal

Judith Vidal

Engineer IV

Ph.D. Metallurgical and Materials Engineering, Colorado School of Mines
M.S. Materials Engineering, Simon Bolivar University, Venezuela
B.S. Materials Engineering, Simon Bolivar University, Venezuela

Judith joined the Thermal Systems Group in 2010 to work in the field of Concentrating Solar Power (CSP). She is developing coatings to protect containment materials at high temperatures (600°â€“900°C) in molten salts and liquid metal alloys. She is using electrochemical and mass changes techniques to study the degradation behavior of these materials. Judith is also studying new formulations of molten salts and liquid metal alloys as thermal energy storage and advanced heat transfer fluids for CSP systems. She developed a new process in molten-salt electrolysis for which a patent was granted. She holds a volunteer appointment as Research Assistant Professor at Colorado School of Mines, where she serves as an advisor and member on graduate theses committees. | 303-275-4290

Photo of Michael Wagner

Michael Wagner

Engineer III

M.S. Mechanical Engineering, University of Wisconsin–Madison
B.S. Mechanical Engineering, University of Wisconsin–Madison

Mike joined the Concentrating Solar Power group at NREL in 2009. His work at NREL includes thermal systems modeling and predictive performance analysis of concentrating solar and power generation systems. Mike has developed several performance models for NREL's System Advisor Model software, including modeling tools for Linear Fresnel, Power Tower, and Parabolic Trough technologies. He is also the developer of a Power Tower layout and optimization tool called SolarPILOT that combines analytical and stochastic methods to define and optically characterize Power Tower solar fields. Mike leads the research and development of a high-temperature solar receiver for super-critical carbon dioxide applications, and he provides expertise in time series analysis of transient and coupled systems, optical and thermal system characterization, computational fluid dynamics, algorithmic optimization, and engineering software development. Before joining NREL, Mike worked as a graduate research assistant at University of Wisconsin–Madison Solar Energy Lab, where he developed an optimization/design tool and detailed transient system component models for power tower technology. | 303-384-7430

Photo of Tim Wendelin

Tim Wendelin

Senior Engineer II

M.S. Physics, Colorado School of Mines
B.S. Physics Engineering, Colorado School of Mines

Tim began at the Solar Energy Research Institute as a student intern in 1981. He worked primarily on thermoelectric devices in the Materials Research group. Ultimately he became involved with thin-film research as applied to reflective surfaces. He completed his graduate thesis in this field. Tim accepted a regular full-time position at SERI in 1984, working in the Thermal Systems group and has become an expert in optical/thermal modeling and testing of concentrating solar power (CSP) optical systems. He has written or cowritten numerous papers on various aspects of CSP technology and holds three patents and two software copyrights.

Tim has developed a variety of optical and thermal test instruments that characterize the performance of various solar concentrator designs. In addition to instrumentation design, he also developed an optical modeling code, SolTrace, filling a gap in the tool set used by industry to design solar concentrating systems. These instruments and the optical modeling tool have been used extensively at NREL and by industry to further the deployment and operation of CSP technology. He has also served as the technical project manager for several projects at the Solar Technology Acceleration Center, including a 1.25-MW Thermal Energy Storage Test Facility. Tim continues to support optical technology development, optical testing of solar concentrating systems, CSP materials characterization, and CSP systems modeling. | 303-384-7475

Photo of Guangdong Zhu

Guangdong Zhu

Mechanical Engineer IV

Ph.D. Mechanical Engineering, University of New Mexico
M.S. Thermal Engineering, Xi'an Jiaotong University
B.S. Thermal Engineering, Northeast China Institute of Electric Power Engineering

Guangdong joined the Thermal Systems Group at NREL in 2010 and is working on research and development of Concentrating Solar Power (CSP) technologies. He serves as the primary operator of the Solar Industrial Mesa Test Area, where optical-efficiency testing for parabolic trough collectors is performed. He is also involved in optical and thermal modeling and economic analysis of solar concentrating systems.

Guangdong has an extensive background in power generation systems, heat-transfer processes, and fluid mechanics. He is also well versed in stress analysis, efficient computing, numerical modeling, and related experimental validation. He has written or cowritten peer-reviewed papers, reports, and presentations in the areas of multiphase flow, power generation systems, and solar thermal power. | 303-275-4497