Trough Receiver Heat Los

Allan Lewandowski

Calvin Feik, Ray Hansen, Steve 

Carl Bingham, Judy Nette

Russ Forristal, Frank Burkho

Bob Meglan, Ed Wolfrum

NREL/PR-550-40023Presented at the 2006 Parabolic Trough Technology Workshop held on February 14-16, 20
Disclaimer and Government License

This work has been authored by Midwest Research Institute (MRI) under Contract No. DE-AC36Department of Energy (the “DOE”). The United States Government (the “Government”) retains athe work for publication, acknowledges that the Government retains a non-exclusive, paid-up, irrepublish or reproduce the published form of this work, or allow others to do so, for Government puNeither MRI, the DOE, the Government, nor any other agency thereof, nor any of their employeeor implied, or assumes any liability or responsibility for the accuracy, completeness, or usefulnesproduct, or process disclosed, or represents that its use would not infringe any privately owned ri

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Project Descriptio

• Design, fabricate, assemble, co

and qualify an experimental cathermal loss testing of full-size receiver elements

• Conduct detailed thermal loss t

variety of receivers

• Assess the impact on thermal l

selected gases within the annumodified Schott receiver
Project Goals

• Improve on the experimental a

DLR, particularly with respect t

• Compare experimental with an

results to improve trough perfomodels

• Use results to better understan

performance issues related to r
DLR Design Issue

Desired Temperature Profile vs DLR D

0

50

100150200250300350400450

-500 0 500 1000 1500 2000 2500 3000 3500 

Thermocouple position from end of receive

DLR w/ CoppDLR w/o CopDesired coppDesired Rece
Design Concept

• Shown with relative expansion at 400
Design Concept

• Shown with relative expansion at 400
Receiver Elements

• Currently in-house

– New Schott (with port to annulus fitted to glass e

• From FPL

– New Schott– New Solel UVAC– Good black chrome (SEGS VI)– Cool & Hot Luz Cermet (SEGS VI generation)– Cool & Hot Luz Cermet (SEGS IX generation)– Fluorescent & Lost Vacuum Luz Cermet (SEGS 

generation)

– Washed Fluorescent Receiver (SEGS IX genera– Cold side and Hot side UVAC receiver (SEGS V

original batch)

– First year Solel Cermet receiver– Refurbished tube w Pyromark paint (SEGS VIII)
Current Status

• FPL shipped 10 receivers

– 1 bare, 1 fluoresced, 8 from various field lo

• Experimental hardware assembled and 

FTLB 118

– DACS based on OPTO22 – Custom heaters and controls from Watlow– Safe Work Permit issued last week; checko– Controls tuned using bare tube receiver

• Temperatures up to 500

o

C

• Additional features

– IR camera for envelop temperatures– Several room temperature measurements t

over time

• Bob Meglan and Ed Wolfrum have dev

monitoring system and tested in the fie

– Will be used in lab in conjunction with rece
FTLB 118
FTLB 118
FTLB 118
Development of a Prototype Device for the non-

Measurement of Hydrogen in Heat Collection El

Problem Importance

Results/Conclusions

HCE failure/degradatfactor for current plan

30-40% failure at SEG

Loss of vacuum (glaspermeation), solar se

Replacement cost is 

Annual operation and 

Oxidation of the heat transfer fluid produces hydrogen gaswhich eventually permeates through the steel tube. This reduces the vacuum and increases heat loss to the outer tube.

When the pressure reaches 0.1 torr (13 Pa) the heat conduction losses are unacceptable.

HCE

We have constructed a device for noninvasive identification and quantitative measurement of gases.We have successfully calibrated the device and proved the concept in the laboratoryWe have successfully demonstrated the device in the field. Hydrogen was measured in several HCE’s in the field. The basic components work in the field and could beruggedized and optimized.

Edward J. Wolfrum, Ph.D.

National Renewable Energy Laboratory

Golden, CO

Robert R. Meglen, Ph.D

Latent Structures, LLC

Boulder, CO

http://www.eere.ene
Hydrogen

2,500 mtorr 200 mtorr

Air

2,500 mtorr 200 mtorrPlasma Emission Demonstration in 
HCE 

in the Field

N Atom lines N2 Molecular ba

H2 Mole

H Atom lines

Unexpected speci

Argon

HCE in the Lab

Emission Spectra Gathered in the Laboratory and 

Wavelength

Emission Intensity Emission Intensity