Smaller heat-collector is moved to stay in focus with the sun, instead of moving reflector. Tracking can be controlled by storing data of predicted solar positions or by applying conventional sun-sensing devices to follow solar movement

Miller, C. G.

Stephens, J. B.

English

NASA Technical Reports Server

$eptember 1975	 B75-10209 
•	 NASA TECH BRIEF 
NASA Pasadena Office 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to.the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Low-Cost Solar Tracking System
 
The problem:	 . 
Conventional Sun-tracking systems for solar energy 
Pivots	 collection are bulky and expensive. They are used to 
move large solar reflectors to follow the Sun so that 
- Movable	 maximum solar energy is absorbed,. Because the Supports
reflectors are large, additional stresses are placed on 
the systems by winds. On the .
 other hand, lighter, 
low-cost tracking systems cannot cope with such heavy 
loads.  
Pivot	 Pivot	 The solution: 
A new configuration makes bulky tracking systems 
unnecessary. Instead of moving the reflector, a 
H	 Secondary	 smaller heat-collector is moved to stay in focus with \	 Reflector	 the Sun. This can be accomplished with a smaller,
low-cost tracking system. 
- Heat-Collector
Pipe
Solar 
Energy 
Stanchion
Reflector 
•	
/ 
Ground 
0.	 Low-Cost Sun-Tracking Arrangement
(continued overleaf) 
	
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https://ntrs.nasa.gov/search.jsp?R=19750000209 2020-03-19T20:26:51+00:00Z
How its done: 
The arrangement of the new tracking system is 
shown in the illustration. Basically, the reflector is 
laid on the ground, using conventional soil stabiliza-
tion methods to keep it from shifting. The reflector 
body is made of concrete, and its surface is covered 
with smooth thin layers of aluminized polymeric film 
which reflect solar energy. The film can be replaced 
periodically as necessary to maintain a highly 
reflective surface. 
The heat-collector pipe is supported by tour bars 
above the reflector surface. One of these is a stanchion 
supporting the entire structure. Two bars on pivots 
are used to translate the pipe with respect to the 
reflector surface. These are pivoted to move as shown. 
The pipe is mounted between the two in a secondary 
reflector [see NASA Tech Brief B75-10210 
(N P0-13580)]. 
Tracking can be controlled in one of two ways. 
First, a control may be provided by a programed 
source. Positions of the Sun are predicted according 
to seasons, and the resulting data are stored to be 
used for the control. The second approach is to apply 
conventional Sun-sensing devices to follow the 
movement of the Sun. Mechanical movement is 
provided by servos.
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP75-10209 
Patent status: 
This invention is owned by NASA, and a patent 
application has been filed. Inquiries concerning 
nonexclusive or exclusive license for its commercial 
development should be addressed to: 
Patent Counsel 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Source: Charles G. Miller and

James B. Stephens of
Caltech/JPL
(NPO- 13579) 
Categories: 06 (Mechanics) 
03 (Physical Sciences) 
B75-10209
	
02 (Electronics Systems)


Low-cost solar tracking system

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