Mechanism uses differential pressure of condensable fluid against fixed piston to equalize radiant energy on pair of blackbody elements

Conroy, B. L.

English

NASA Technical Reports Server

October 1975	 B75-10237 
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. 
Automatic Solar Tracker 
A new solar tracker requires no servo power and 
needs minimal maintenance. It uses solar energy 
directly to keep the axis of a Sunfall collector pointed 
at the Sun. The tracking mechanism uses differential 
pressure of a condensable fluid such as Freon against 
a fixed piston to equalize the radiant energy on a pair 
of blackbody elements. The blackbody elements are 
used to heat the fluid to generate the expansion. 
The illustration shows the tracker with a typical 
energy converter attached. The tracker axis is
pointing slightly away from the Sun, and the radiant 
energy falls more directly on the blackbody near the 
Sun. This blackbody rises in temperature, heating 
the working fluid in contact with it. The working fluid 
on the warmer side expands against the piston more 
than the fluid on the cooler side. This causes the 
tracker axis to move toward the warmer side until 
both blackbodies receive equal radiant energy and 
the axis of the tracker points directly at the Sun. 
Tracker Axis Sunrays 
Energy
/ 
Converter
	
Lower	 Fluid	 Higher 
	
Temperature	 Chambers	 Temperature 
	
Blackbody	 -	 Blackbody 
..._ 
	
Lower-Pressure	 Higher-Pressure 
	
Working Fluid	 Working Fluid 
Arc 
	
Arc	 P1st 
	
Path	 I Path 
	
L'nkag>	
Fixed 
Piston 
Support 
Pivot
Support Tower 
Automatic Solar Tracker
(continued overleaf) 
	
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https://ntrs.nasa.gov/search.jsp?R=19750000237 2020-03-19T20:29:09+00:00Z
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
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Reference: TSP75- 10237
Patent status: 
NASA has decided not to apply for a patent. 
Source: Bruce L. Conroy of 
Caltech/JPL 
(N P0-13630) 
Categories: 03 (Physical Sciences) 
B75-10237
	 06 (Mechanics)


Automatic solar tracker

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