GreenMountain Engineering Introduces the First Commercially Available Diagnostic Instrument for Measuring Solar Tracker Performance

SAN FRANCISCO, CA – Jan. 29, 2008 – GreenMountain Engineering today announced its new diagnostic instrument for measuring tracker performance, the Trac-Stat SL1. The SL1 is a high-resolution datalogging sensor that mounts on a solar tracker. It records the angle of error between the sun and the tracker for use in the development of tracking, concentrating photovoltaic (CPV) and solar thermal systems.

The SL1 was developed to meet the need for a tool that provides consistent and accurate information about the pointing error of solar trackers. With an accuracy of +/-0.02°, the SL1 meets the precision requirements of CPV tracking systems. The data collected can be used to characterize the error in a tracking system, log controller performance over time, and calibrate and align trackers. This information is essential for the development of the high-accuracy tracking systems required for CPV.

Utility-scale solar company GreenVolts is testing GreenMountain's Trac-Stat SL1 as part of its concentrating photovoltaic system.  The SL1 allows developers of cutting edge CPV technology to minimize a key area of uncertainty. “If you don’t know where your tracker is pointing, you can’t evaluate the performance of your system. Once you know how well your tracker works, you can focus on your core technology. It’s a lot of risk mitigation for a little money,” says Max Davis, Principal Engineer and Solar Specialist at GreenMountain.

The Trac-Stat SL1 provides data on azimuth and elevation pointing error using two independent sensing systems: The wide-angle sensor is capable of locating the sun over a 60-degree field-of-view with +/- 0.5° accuracy; the narrow-angle sensor is effective over a 5-degree field-of-view with +/-0.02° accuracy. These two sensors, in combination with optics, filtration and proprietary algorithms, provide flexible and robust performance under a range of operating conditions.

The SL1 offers the flexibility of analog or USB output with both interactive and stand-alone operation modes. In interactive mode, the operator can read current sun position data over a USB connection for tracker calibration and monitoring. In stand-alone mode, the SL1 can log data to internal memory over extended periods of operation for later download and analysis.

The Trac-Stat SL1 will be commercially available in March 2008. GreenMountain is currently accepting orders. For more information visit www.greenmountainengineering.com/greentools.

GreenMountain Engineering, LLC is a consulting firm specializing in the design of new devices, products and production systems for clients in renewable energy and other clean technologies. GreenMountain is known for innovative approaches to new products and manufacturing equipment. The firm’s solar power practice—with clients such as Evergreen Solar, SunPower Corporation, and SolFocus—encompasses the entire supply chain, from materials and cells to modules and systems. GreenMountain’s offices are in San Francisco, CA and just outside Boston in Somerville, MA.

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