Device provides low-cost unit for efficiently transferring heat between, either to or from, flat surface and central point or region. It is based upon vapor heat transfer principle and therefore, extends applicability of heat pipe

Jenkins, R. V.

Sabol, A. P.

English

NASA Technical Reports Server

NASA TECH BRIEF 
Langley Research Center H[1
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February 1975	 B74-10291 
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. 
Flat Device for Heat Concentration or Dispersion 
Sun Rays
	
	 Sun Rays 
sEcTloNAA
Heat Concentrator or Disperser Unit 
The device illustrated, provides a low-cost unit for 
efficiently transferring heat between, either to or. 
from, a flat surface and a central point or region. It is 
based upon a vapor heat transfer principle and, 
therefore, extends the applicability of the heat pipe. 
Possible uses are varied, ranging from a solar heat 
concentrator or an electronic cooling device to 
geothermal power applications. The present intended 
application is as a solar heat collector to operate a 
newly developed type of air-conditioner.
The heat concentrator and disperser unit depends 
upon the transfer of a cQndensable vapor for the 
conductance of heat from one point to another. The 
concentration or dispersion of heat from a central 
region to a flat surface by the use of heat pipes is not 
practical, as it requires the incorporation of a 
complicated geometrical arrangement of a multi-
plicity of heat pipes. 
The heat concentrator or disperser unit as shown 
consists of a sealed enclosure which, if necessary as for 
(continued overleaf) 
This document was prepared under the Sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United Slates
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	
will be free from privately owned rights.
	 - 
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a solar heat concentrator, is partially encased in an 
insulating material. Heating or cooling is applied to 
ohe or both of the flat surfaces. In this application, 
Sun rays are used for heating, and they only strike one 
surface which is suitably treated and shielded against 
the loss of heat waves, thus allowing for a very 
efficient capture of the solar radiation. A wick Of 
suitable material bears against the interior flat 
surfaces and against the edges of the sealed enclosure. 
A porous wick joins both the top and bottom surfaces 
of the wick and is shaped so as to leave the channels 
open to the free passage of vapor from the wick to heat 
the inner surface. 
The porous wick, lying between and touching the 
wick, is appropriately designed so as to take the best 
advantage of the fluid dynamic properties of both the 
vapor and the liquid used. Thus, in the design of 
large-scale concentrators, the porous wick may consist 
of single or multiple radial segments. The inner 
surface is centrally located and is of suitable design so 
as to function either as a heating surface or as a• heat 
sink, whichever mode a particular application may 
require. In the application as a solar heat concen-
trator, the central portion acts as a vapor-condensing 
surface. The volume contained within the inner 
surface permits the installation of fluid-type, thermal 
and mechanical, or thermionic devices. 
In operation, a liquid having the desired physical 
properties for a particular application is sealed in the 
enclosure and saturates both wicks. The liquid and 
the amount are preselected in order to control the 
vapor pressure of the unit during operation. 
In the illustrated application, Sun rays strike the 
exposed surface and heat the liquid in the wick to the 
vaporization point. Because a heat sink exists interior 
to the inner surface, it remains cooler than the vapor 
temperature of the fluid. Consequently, vapor 
condensation takes place on the inner surface and 
depletes the vapor about the central region. This 
causes a migration of warmed vapor from the wicks,
and by a capillary action the wick returns the 
condensed vapor to repeat its cycle. Heat is therefore, 
in this instance, transferred by the vapor from the 
warmed surface to the cooler inner surface and the 
central region for utilization. 
The vapor pressure is controlled by the type and 
quantity of liquid soaked in the wicks whether the unit 
is made to operate as a flat heat dispenser or as a heat 
concentrator. In use as a heat concentrator, the wick 
does not completely enclose the inner surface so as to 
allow that surface to collect and condense the heated - 
vapor effectively. 
The flat surfaces can be of any desired shape and 
not necessarily circular. Instead of the central region 
and the inner surface acting as heat sink, as in the 
illustration, this central region can be used as a heat 
source where the flat surfaces become heat dispersers. 
Heat from the flat surfaces can be dispersed either by 
radiation, convection, or conduction. 
Note: 
No further documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Langley Research Center 
Mail Stop 139-A 
Hampton, Virginia 23665 
Reference: 74-10291 
Patent status: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
Patent Counsel - 
Langley Research Center 
Mail Stop 313 
Hampton, Virginia 23665 
Source: Renaldo V. Jenkins and Alexander P. Sabol
Langley Research Center 
(LAR-1 1699)
C 
I 
. 
Categories: 03 (Physical Sciences) 
04 (Materials) 
B74-10291
	 06 (Mechanics)


Flat device for heat concentration or dispersion

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