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Thermal Scout Software

National Renewable Energy Laboratory

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Heat Collection Element Survey System software<br />
Heat Collection Element Survey System software

Parabolic troughs with receiver tubes
Parabolic troughs with receiver tubes

Technology Marketing Summary

A parabolic trough power plant generates electricity using concentrated sunlight as the heat source for its power cycle. A parabolic trough plant is comprised of multiple rows of single- linear focusing collectors concentrating direct beam radiation onto tubular receivers (also known as heat-collection elements [HCEs], absorbers, or receivers) located along the focal line. Receivers are designed to minimize heat loss to the environment while absorbing as much sunlight as possible. NREL has developed an absorber survey system that allows plant operators to rapidly survey their receiver performance during operation.


The Thermal Scout software is used in connection with a portable system comprised of an infrared (IR) camera, global position system (GPS) receiver, and a computer (which would be acquired separately by the user).  The software uses GPS data to automate infrared camera image capture and temperature analysis of receivers in a parabolic trough field.  This system easily integrates with a vehicle of choice, such as a SUV.  The GPS is placed on the roof of the vehicle recording the user’s location in the plant, and triggering the IR camera positioned to image the nearby absorber tube.   An operator drives the vehicle once along each row, while a NREL’s custom software control package gathers the data.  IR images of every absorber are obtained and automatically processed.  This automated system is fast and typically allows the operator to evaluate the thermal properties of over 6000 receivers per day. 

The receivers glass temperature is a strong indication of how well an absorber is performing. Cooler glass indicates less heat is lost though dissipation to the environment, and thus more energy is imparted to the heat transfer fluid (HTF).  A cold receiver will have a glass temperature of 105oC or less.  A hot receiver can have a glass temperature of >150oC.  A receiver may be hot due to a loss of vacuum or the presence of hydrogen in the annulus. 


The naked eye cannot determine the performance of a receiver. Instrumentation must be used to determine the heat losses are too high and thermocouples or an IR camera can be used to safely do this. NREL survey system mitigates the need for staff to instrument suspect receivers while rapidly measures receiver performance during operation.  Additionally, this software is completely automated so that the user ONLY has to drive down each row allowing the program to trigger the camera at the correct time collecting the desired images and processing them. Use of the system reduces the labor involved in surveying receivers and analyzing them in a field from several months or longer to approximately one week.   

Applications and Industries

Parabolic Trough Plants

Technology Status
Development StageAvailabilityPublishedLast Updated
Development - Developed and tested, user guide availableAvailable08/18/201102/29/2012

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To: Jean Schulte<>