The heliostat field has 218 individual heliostats. This capability directly supports the SunShot goals by providing flux levels of greater than 300 W/cm²
and total power in excess of 6 MW_t. Each heliostat has two motors and two drives (one azimuth and one elevation), one 480 V power box, one electronics box, and one control box and associated cabling. The total reflective area on each heliostat is 37 m². The reflectivity on the recently replaced facets is 96%.

The tower is a 61 m (200 ft) high concrete structure with three test locations on the north side and the top of the tower. The tower can support testing for CSP experiments and large-scale, high-flux materials samples. The equipment in the tower includes a 100-ton capacity elevating module for lifting experiments to the top of the tower, internal cranes for receiver fabrication, water glycol cooling systems and air coolers to provide heat removal from experiments, air compressors, control valves, generators, uninterruptible power supplies, piping systems, and pressure-relief valves.

The molten salt test loop directly supports the SunShot goals by providing development for thermal energy storage costs ≤$15/kWhth and by allowing greater collection efficiencies and higher-temperature operation for linear Fresnel and trough systems through utilization of molten salt HTF. The facility also provides a means of performing accelerated lifetime testing on components, thus reducing the risk of the technology. Though operating below 600° C, many of the lessons learned at this facility will be directly applicable to molten salt systems operating in the SunShot temperature range ≥ 650° C.

The AZTRAK (AZimuthal TRAcKing) Rotating Platform system was originally designed and installed at Sandia during the early 1980s to enable more accurate and rapid thermal performance testing of parabolic concentrators. When a parabolic concentrator (or any other solar collecting device) is equipped with an elevation tracker and mounted on the rotating platform, the solar position of the collector can be continuously maintained at any desired orientation.

The High Temperature Fluid Loop was designed in conjunction with the AZTRAK system to supply heated fluid to the collector inlet, at steady-state fluid temperatures up to 375°C, to evaluate the thermal performance of a parabolic concentrator at system operating temperatures.

The rotating platform and the high temperature fluid loop are a unique national facility:

• Ability to track sun in azimuth at 0 degrees incidence angle (eliminate off-axis cosine affects), but can track at any desired incident angle.
• Azimuth tracking: Resolution of 0.09 deg., accuracy of 0.30 deg.
• Elevation tracking: Resolution of 0.04 deg.; accuracy of 0.08 deg.
• Heat transfer fluid thermal stability at the test device of 0.2C at temperatures up to 375C at a flow rate of 550.2 l/min for a 15 to 20 minute test window
• Solar averaged mirror specular reflectivity measured before each test
• Documented collector mirror and receiver alignment

To cover the temperature range of near ambient temperatures up to 375 used for trough testing two different fluids are used. Water is used for testing where the fluid temperatures are near ambient. The high temperature fluid loop contains oil, Syltherm 800, and is used from 70°C up to 375°C.

SNL’s Photovoltaic and Distributed Systems Integration department and staff from the NSTTF worked with SunPower to install 110 kWe of SunPower’s new C7 low-concentration PV systems at the NSTTF. This is the first demonstration of a utility-size CPV test at SNL. The PV Reliability group worked closely with SunPower during the development and early implementation stage to support design optimization. SNL is using the systems data to evaluate the reliability of this low-concentration system. SunPower is using the site to test new components in side-by-side comparisons. The groups are working together to improve performance models specific to this technology.

Concentrating photovoltaic array located at the NSTTF, hardware provided and operated by SunPower Corporation.

Optical equipment located in this lab space and tools developed, using DOE funds, allows for optical characterization of heliostat and dish facets. These flexible analytical tools, along with the on-site expertise currently support the evaluation and development of low-cost, high-performance heliostat facets. The tools are also applicable to assembly/production line environments. In addition, field support for characterization and alignment of CSP systems is provided. SOFAST, a highly accurate fringe-reflection-based measurement tool, is used to characterize and set the focus heliostat facets in the laboratory. H-FACET is an optical-based alignment tool that is used to efficiently re-align the facets after re-attaching them to the heliostat. AIMFAST is used to characterize dish facets and align dish systems.

This area of the site allows industry partners to install full-scale solar dishes for long-term reliability testing and evaluation. There are currently ten Stirling Energy Systems (SES) dishes and six Infinia dishes at this location. The site also includes two SNL-developed solar dishes that are available for research. Solar dishes can be used for the high-temperature portions of the SunShot goals.

A solar furnace uses a heliostat that tracks the sun to direct sunlight onto a mirrored parabolic dish. Because the focal point of the dish does not move, it is simple to install experiments. The power level of the furnace is adjusted using an attenuator that works like a venetian blind located between the heliostat and the dish.

The Test Facility has a small solar furnace with:

• High-temperature solar thermochemical water-spitting experiments
• A heliostat that is 95 m²
• A dish that is 6.7056 meters in diameter

This furnace provides

• 16 kW total thermal power
• Peak flux up to 500 W/cm²

The furnace has a power control to simulate nuclear and other thermal transients.

Applications include:

• Investigating the thermophysical properties of materials in concentrated sunlight, including thermal expansion, thermal conductivity and diffusivity, specific heat, mechanical properties, and spectral emissivity and absorptivity
• Simulation of thermal effects of nuclear explosions on materials and components
• Determining the performance and failure thresholds of high-temperature ceramic and refractory materials

• The High-Flux Solar Simulator with Automated Sample Handling & Exposure System (ASHES) is a one-of-a-kind capability which can be used 24/7 with metal-halide lamps.  ASHES provides accelerated lifetime aging tests for materials under high-temperature/high-flux conditions.  A robotic sample-handling system can be used to move multiple coupons automatically into and out of the concentrated flux sequentially to expose the samples to predetermined temperatures, fluxes, and/or durations.  The peak irradiance is ~1.1 MW/m²  with an average irradiance of ~0.9 MW/m² over a spot size of ~1 inch (2.5 cm).

View a list of common frequently asked questions.