Silicon solar cell, attached to each viewpoint, monitors that incandescent emission from the hot interior of a furnace without interfering with the test assembly or optical pyrometry during the test. This technique can provide continuous indication of hot spots or provide warning of excessive temperatures in cooler regions

Zellner, G. J.

English

NASA Technical Reports Server

Retaining Cap
Solar Cell 
May 1968
	 Brief 68-10148 
AEC-NASA TECH BRIEF	
_1a 
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of the U.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
application. Tech Briefs are published by NASA and may be purchased, at 15 cents each, from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Silicon Solar Cell Monitors High Temperature Furnace Operation 
ICY C 
TES
Front View 
INSTALLATION OF SILICON SOLAR CELL	 RECORDING CIRCUIT 
direct radiant emission from the hot body. Because of 
the small size of the solar cells it is possible, on a 
half-inch diameter or larger sight port, to view the 
same body with a conventional optical pyrometer 
while the solar cell is installed. This permits direct 
individual calibration if required. The output of the 
solar cell is connected directly to a voltmeter, recorder, 
or alarm system. Solar cells thus installed on a high-
temperature thermocouple test furnace have been 
found to operate within a +270 band over a tempera-
ture range from 22000 to 4800° R. 
Notes: 
I. The overall cost of a solar cell/voltmeter unit is 
under $50 (cells cost under $2.00). 
2. Thermocouples capable of operating over the 
same range with similar accuracy would cost 
between $500 and $1000 each, and would possibly 
affect test assembly geometry. Readout equipment 
would be an additional cost. 
3. Automatic optical pyrometers for this temperature 
range cost approximately $5000 each.
(continued overleal) 
The problem: 
To continuously monitor a furnace operating at 
high temperatures and pressures without interfering 
with the test assembly or optical pyrometry during 
the test, and at lowest possible cost. 
The solution: 
Attach a small silicon solar cell to each viewport to 
monitor the incandescent emission (which is a func-
tion of temperature) from the hot interior of the 
furnace. This technique can provide continuous indi-
cation of hot spots or provide warning of excessive 
temperatures in cooler regions. Since silicon solar cells 
are self-generating, they can be connected directly to a 
calibrated meter or used as the control signal source 
for an alarm system. Normal optical pyrometry is still 
possible for higher accuracy measurements. 
How it's done: 
Silicon solar cells 0.2 inch x 0.2 inch are cemented 
directly to the pyrex or quartz sight ports, using a clear 
eooxv. The cells are located on the ports to receive 
This document was prepared under the sponsorship of the Atomic 
Energy Commission and/or the National Aeronautics and Space 
Administration. Neither the United States Government nor any per-
son acting on behalf of the United States Government assumes any
liability resulting from the use of the information contained in this 
document, or warrants that the use of any information, apparatus, 
method, or process disclosed in this document may not infringe pri-
vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19680000148 2020-03-12T05:28:26+00:00Z
4. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
AEC—NASA Space Nuclear 
Propulsion Office 
U.S. Atomic Energy Commission 
Washington, D.C. 20545 
Reference: B68-10148
Patent status: 
No patent action is contemplated by AEC or 
NASA.
Source: G. J. Zellner
of Westinghouse Astronuclear Laboratory 
under contract to
AEC-NASA Space Nuclear Propulsion Office 
(NUC-10163) 
Brief 68-10148	 Category 01


Silicon solar cell monitors high temperature furnace operation

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