A combined solar energy collector, fluid chiller and energy storage system is disclosed. A movable interior insulated panel in a storage tank is positionable flush against the storage tank wall to insulate the tank for energy storage. The movable interior insulated panel is alternately positionable to form a solar collector or fluid chiller through which the fluid flows by natural circulation

Jensen, R. N.

English

NASA Technical Reports Server

United States Patent [111 4,192,290 
Jensen [45] Mar. 11, 1980 
COMBINED SOLAR COLLECTOR AND 
ENERGY STORAGE SYSTEM 
Inventor: 
Assignee: 
Ronald N. Jensen, Hampton, Va. 
The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
Appl. No.: 900,843 
Filed: Apr. 28,1978 
Int. Cl.2 ................................................. F24J 3/02 
U.S. Cl. .................................... 126/437; 126/434; 
165/32; 126/419 
Field of Search ............... 126/270, 271, 419, 418, 
126/422,428,430,434, 450, 437; 237/1 A; 
165/32,49, 106 
References Cited 
U.S. PATENT DOCUMENTS I 
2,388,940 11/1945 Taylor .................................. i26/27i 
2,595,905 5/1952 Telkes ................................... 237/1 A 
4,027,821 6/1977 Hayes et al. ..................... 126/400 X 
4,033,325 
4,050,508 
4,051,890 
4,082,080 
4,083,490 
4,116,222 
4,137,964 
4,149,589 
7/1977 
9/1977 
10/1977 
4/1978 
4/1978 
9/1978 
2/1979 
4/1979 
Walker ................................. 126/434 
Buckley ............................... 126/271 
Melchior ................................ 165/32 
Pittinger ............................... 126/271 
Cunningham et al. .............. 126/419 
Seifried ................................ 126/271 
Buckley ............................. 165/32 X 
Hopman ................................. 165/32 
Primary Examiner-James C. Young 
Assistant Examiner-Larry Jones 
Attorney, Agent, or Firm-Wallace J. Nelson; John R. 
Manning; Howard 3. Osborn 
1571 ABSTRArn 
A combined solar energy collector, fluid chiller and 
energy storage system. A movable interior insulated 
panel in a storage tank is positionable flush against the 
storage tank wall to insulate the tank for energy storage. 
The movable interior insulated panel is alternately posi- 
tionable to form a solar collector or fluid chiller 
through which the fluid flows by natural circulation. 
6 Claims, 7 Drawing Figures 
https://ntrs.nasa.gov/search.jsp?R=19800012326 2020-03-21T02:29:03+00:00Z
U.S. Patent MU. 11,1980 Sheet 1 of 2 
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4,192,290 
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FI .G. 1 
20 I6 ‘17 11: J FIG. 2 
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64 FIG. 3 
U.S. Patent MX. 11,1980 
HEAT 
I EXCHANGER 
4 
Sheet 2 of 2 4,192,290 
FIG. 4 
STORAGE 
TANK 
FIG. 6 
FIG. 5 
FIG. 2 
f 
Y 
4,192,290 
P 
COMBINED SOLAR COLLEmOR AND ENERGY 
STORAGE SYSTEM 
ORIGIN OF THE INVENTION 
The invention described herein was made by an em- 
ployee of the United States Government and many be 
manufactured and used by or for the Government for 
governmental purposes without the payment of any 
royalties thereon or therefor. 
BACKGROUND O F  THE INVENTION 
This invention relates to a solar heating system. More 
particularly it relates to a solar heating system compris- 
ing a combined solar collector, liquid chiller, and stor- 
age tank, featuring a movable thermally actuated inte- 
rior insulated panel. Most solar heating systems in the 
prior art have used flat plate collectors separate from a 
storage tank. These systems usually require a pumping 
action to move hot fluid from the collector into a stor- 
age tank which is lower than tlie collector. Also, the 
collectors are subject to freezing unless complicated 
evacuation systems are provided or expensive non- 
freeze fluids are used. 
There have been some systems which have combined 
collectors and storage tanks, e.g., the Steve Bear house 
in Arizona or the Harold Hays “Skytherm” house. 
These systems are usually equipped with external insu- 
lation which require physical manipulation to make the 
system work. They also limit the heater to a southern 
wall or ceiling, thus the structure must be built to suit 
the needs of the collector. 
Thermal diodes have also been offered as a means to 
keep energy in storage (“Proceedings of the Workshop 
on Solar Energy Storage Subsystems for Heating and 
Cooling of Buildings”, Apr. 16-18, 1975, NSF-RA-75- 
041, page 141, “Storage Aspects of Thermic Diode 
Solar Panels”.). For these systems to work, piping must 
be incorporated into the collector and employed very 
carefully. Thermal diodes also do not eliminate freeze 
unless expensive nonfreeze fluids are used. The boiling 
and freezing of the fluid in the collector has always been 
a problem with solar energy heating systems. The pres- 
ent invention neatly solves the problem by utilizing a 
movable insulated panel inside the storage tank. In the 
collecting mode the interior panel is moved away from 
the storage tank wall thus forming a solar collector 
composed of a transparent thermal cover, the tank wall, 
the working fluid and the movable interior panel. The 
fluid moves from the tank and through the collector and 
back to the tank by natural circulation. The chilling 
mode is similar to the collecting mode with the trans- 
parent cover removed such that heat radiates from the 
tank wall to the environment. In the storage mode the 
movable interior insulated panel is moved up flush to 
the tank wall thus eliminating the collector fluid flow 
path and evacuating practically all fluid from the collec- 
tor. In the storage mode heat transfer between the tank 
fluid and the tank environment is essentially eliminated 
thus precluding possibility of freezing or boiling of the 
fluid. 
OBJECTS OF THE INVENTION 
It is an object of the present invention to provide a 
combined solar collector, fluid chiller, and energy stor- 
age system in a single unit such that external piping is 
eliminated. 
5 
10 
15 
20 
25 
30 
35 
40 
45 
50 
55 
60 
65 
2 
It is a further object of the invention to provide a 
solar system which utilizes a natural circulation collec- 
tor such that pumps are eliminated. 
It is another object of the invention to provide a 
combined solar collector, fluid chiller, and energy stor- 
age in which an easy and simple method is employed to 
preclude freezing or boiling of the system fluid in the 
collector. 
Other objects and advantages of the present invention 
will be readily apparent from the following description 
and drawings which illustrate a preferred embodiment 
of the present invention. 
SUMMARY OF THE INVENTION 
The present invention involves a combined solar 
energy collector, fluid chiller, and energy storage sys- 
tem. The invention includes a liquid filled, thermally 
insulated fluid storage tank of which one wall is a solar 
radiation collector, a thermal insulated panel located 
inside the storage tank which is parallel to and is mov- 
able with respect to the collector wall whereby the heat 
transfer between the tank liquid and the collector sur- 
face is regulated by positioning of the interior insulated 
movable panel. 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIG. 1 is an elevational sectional view of a combined 
solar energy collector, fluid chiller, and energy storage 
system in the storage mode as taken along line 1-1 of 
FIG. 3; 
FIG. 2 is an elevational sectional view similar to FIG. 
1 and showing the system in the heat transfer mode; 
FIG. 3 is an elevational sectional view taken along 
line 11-11 of FIG. 2; 
FIG. 4 is a schematic diagram showing the hookup of 
an external heat exchanger to the system; 
FIG. 5 is a perspective view showing a removable 
secondary panel; 
FIG. 6 is an exploded perspective view of tie pins and 
turnbuckle employed in the present invention; and 
FIG. 7 is a sectional view of a thermal actuator em- 
ployed in the present invention. 
DESCRIPTION OF THE PREFERRED 
EMBODIMENT 
FIG. 1 shows an elevational sectional view of the 
preferred embodiment of a combined solar energy col- 
lector, fluid chiller, and energy storage system. A water 
storage tank generally designated by the reference nu- 
meral 10, includes a rectangular horizontal base 16 with 
rear wall 18 and sidewalls 28 (shown in FIG. 3) extend- 
ing vertically upward therefrom. Tank 10 is open at the 
top and is filled with water 12 to level 14. 
Base 16 and walls 18 and 28 are insulated with con- 
ventional thermal insulation 17. The front wall of tank 
10 is a collector wall 52 which is coated with solar 
radiation absorptive paint 53 on the exterior side. 
Spaced from the collector wall 52 is a transparent panel 
50 through which solar radiation may pass. A stagnant 
air space 54 is maintained between transparent panel 50 
and collector wall 52 to thermally insulate collector 
wall 52 from the outside environment. The transparent 
panel 50 as well as the rest of the system is supported by 
housing 20 which covers all surfaces of tank 10 except 
the collector wall 52. A removable cover 60 having 
thermal insulation 17 is fitted to seal the tank 10 at the 
top from the outside environment. 
4.192.290 
3 
A movable thermal insulation panel designated gen- 
erally by the reference numeral 62, is located inside tank 
10. Movable panel 62 is constructed of insulation mate- 
rial having insulating properties unaffected by submur- 
sion in water 12. Two to four inches of cellular glass 55 
is utilized for panel 62 in the preferred embodiment, 
with one-half inch of a soft and flexible cellular insula- 
tion 56 such as “ARMFLEX” on the front to provide 
an efficient seal when pafie1 62 is pressed against collec- 
tor wall 52. Front tie pins 30 and rear tie pins 31 extend 
from walls 52 and 18, respectively to threaded turn- 
buckles 34. The tie pins 31 and 30 support the walls to 
preclude bulging thereof due to water pressure; the 
threaded turnbuckle 34 provides a tensing adjustment 
for tie pins 31 and 30. 
Referring now to FIG. 6, there is shown an exploded 
view of turnbuckle 34 and tie pin 30 assembly as em- 
ployed in the present invention. Threads 33, 35 and 37 
are designed such that rotating turnbuckle 34 in the 
direction of the arrow brings the threaded ends of tie 
pins 30 and 31 closer together thus increasing tension; 
and rotating turnbuckle 34 in the direction opposite of 
the arrow will decrease tension. Tie pin 30 also extends 
through holes 42 (in FIG. 3) in panel 62 thus also serv- 
ing as a track whereby panel 62 is supported and upon 
which it may slide. 
Referring to FIG. 2, springs 32 exert a force between 
turnbuckles 34 and panel 62 sufficient to press panel 62 
flush against wall 52 and perimeter insulation seals 64. 
Movable panel 62 may be moved toward turnbuckle 34 
by actuating thermal actuators 68, anchored on collec- 
tor wall 52 or insulation panel 62, which exert a force on 
panel 62 in opposition of the force of springs 32 and of 
sufficient magnitude to move panel 62 along tie pin 30 
away from wall 52. In the preferred embodiment, a 
thermal actuator 68 is located near each tie pin 30. 
Thermal actuators 68 of the preferred embodiment 
are designed to expand when wall 52 reaches a tempera- 
ture of 1 lo” F. Alternatively, they may be designed to 
allow the panel to move back when the temperature of 
wall 52 exceeds the water 12 temperature or to remain 
closed under all circumstances when the wall 52 
reaches temperatures near freezing or near boiling of 
water 12. 
The thermal actuator 68 is shown in more detail in 
FIG. 7. A piston 26 is slidably positioned in housing 25 
to seal in a condensible gas 27. As the temperature of 
actuator 68 increases, the gas 27 expands and vaporizes 
and pushes apart piston 26 and housing 25. In an alterna- 
tive thermal actuator construction, freon is contained in 
a bellows similar to that of an automobile thermostat 
having a pressure plate unit and as the freon heats up, it 
expands, in turn expanding the bellows and urging the 
pressure plate 26 against, and consequently moving, 
panel 62. Other apparatus for moving panel 62 may be 
used in place of actuator 68 including, but not limited to, 
electric motors, external mechanical or pneumatical 
devices and the like. Also, the buoyancy (whether posi- 
tive or negative) of the panel 62 material may be utilized 
for moving panel 62. 
Referring back of FIG. 2 stratification panels 40 en- 
hance thermal stratification of water 12, whereby a 
greater temperature difference is achieved between the 
temperature of water 12 at the top of tank 10 and at the 
bottom 16 of tank 10 and furthermore since thermal 
mixing is inhibited, a higher water temperature is ob- 
tained at the top of tank 10 than would be possible 
without stratification. 
4 
Water level 14 is maintained above the top of mov- 
able panel 62 thus permitting the flow of water 12 there- 
over. 
Referring now to FIG. 3 there is shown a sectional 
5 view of a combined solar energy collector, fluid chiller 
and energy storage system from the rear. As shown 
therein, stratification panels 40, movable panel 62, and 
perimeter insulation seals 64 run the width of tank 10. 
Perimeter insulation seals 64 are affixed to tank bottom 
10 16 and collector wall 52. Sidewalls 28 are insulated with 
conventional thermal insulation 17 and extend verti- 
cally upward from base 16. This view also shows holes 
42 in movable panel 62. 
The system is operable in four modes: the solar radia- 
15 tion collecting mode; the energy storage mode; the 
liquid chilling mode; and the energy use mode. 
FIG. 1 shows the system in the energy storage mode. 
Movable panel 62 is flush against collector wall 52 and 
perimeter insulation seals 64. In the energy storage 
20 mode heat transfer is essentially precluded between 
tank fluid 12 and the outside environment. Freezing of 
the water film between the collector wall 52 and the 
movable panel 62 will not cause failure due to its thick- 
ness. 
FIG. 2 shows the system in the solar energy collect- 
ing mode. Thermal actuators 68 have pushed back mov- 
able panel 62 creating a fluid flow path, designated by 
arrow 70, between movable panel 62 and collector wall 
52 and perimeter insulation seals 64. Solar radiation 51 
30 strikes and heats collector wall 52. The heat is trans- 
ferred to fluid 12 in flow path 70 by conduction and 
convection between fluid 12 and collector wall 52. 
Fluid 12 moves upward through flow path 70 by natural 
circulation and into tank 10. 
The system in the liquid chilling mode is similar to 
that of the solar collecting mode of FIG. 2 except the 
transparent panel 50 may be removed and the actuators 
(mechanical type) are worked opposite of the solar 
collecting mode. The fluid chilling mode is used when 
40 the exterior environment temperature is less than the 
temperature of fluid 12 and it is desired to decrease the 
fluid 12 temperature. Under these conditions fluid 12 
will flow downward, through flow path 70 by natural 
circulation giving up heat by conduction and convec- 
45 tion through collector wall 52 to the exterior environ- 
ment. 
FIG. 4 is a schematic showing a system capable of 
utilizing fluid 12 for heating or cooling purposes: the 
energy use mode. For heating, hot fluid 12 from the top 
50 of tank 10 is pumped to a heat exchanger, e.g., a radia- 
tor, where the fluid 12 gives up heat, and is then cycled 
back to the bottom of the tank 16 to be reheated. For 
cooling, cool fluid 12 from the bottom of tank 10 is 
pumped to a heat exchanger, where the fluid 12 gains 
55 heat, and is then recycled back to the top of tank 10 and 
cooled. 
As shown in the exploded perspective view of FIG. 
5, a secondary panel 82, removable to expose tank wall 
18 to a room to be heated or cooled by heat transfer 
60 between the air in the room and fluid 12 in tank 10 via 
wall 18, may be employed either exterior to or interior 
to the wall 18. Also, a solar radiation reflector 44 posi- 
tionable to reflect the sun’s rays onto collector wall 52 
may be used. Alternatively, tank 10 may be constructed 
The above description and drawings are only illustra- 
tive of one embodiment which achieves the objects, 
features and advantages of the present invention, and it 
25 
35 
. . 
65 with wall 52 tilted at an optimum angle to the sun. 
4,192,290 
5 6 
is not intended that the present invention be limited 
thereto. All modifications of the present invention 
which come within the spirit and scope ofthe following 
claims are considered part of the present invention. 
comprising a transparent panel positioned parallel to 
and spaced from said collector wall of said tank. 
3. A combined solar energy collector, fluid chiller, 
and energy storage system as in claim 1 wherein said 
5 panel moving means comprises a thermal actuator to 
trigger a desired move of said panel parallel to and 
away from said collector wall when said liquid attains a 
and energy storage system comprising: predetermined temperature, a set of spaced front and 
(a) a tank for containing a liquid; rear tie pins perpendicular to and supporting said ther- 
(b) a solar energy collector surface forming a wall of 10 mal insulation panel, each front tie pin being thread- 
said tank; ingly connected to a corresponding rear tie pin by a 
(c) a thermal insulation means for thermally insulat- turnbuckle, said front tie pins extending from the collec- 
ing said liquid contained in said tank from the exte- tor Wall and slideably received through said thermal 
rior environment of said tank, said thermal insula- insulation panel, a Set Of springs corresponding to said 
tion including a thermal insulation panel 15 set of front and rear tie pins, each spring positioned 
around and with its longitudinal axis parallel to one of located inside said tank, the major surface of said said said front tie pins, and each spring positioned be- 
tween and pushing against said thermal insulation panel panel being parallel with the collector wall; 
(d) thermally responsive panel moving means posi- and one of said turnbuckles. 
tioned to move the 4. A combined solar energy collector, fluid chiller, 
first position in which the panel is displaced from in claim 1 wherein a plu- 
said collector surface to allow the liquid to move rality of stratification panels are positioned horizontally 
into contact with the collector surface, to a second inside said tank. 
position where the panel affronts the collecting 5. A combined solar energy collector, fluid chiller, 
wall; whereby heat transfer between said liquid and 25 ?nd.energY storage system as in claim 1 wherein said 
said collector wall is controlled by the movement liquid 1s circulated from said tank through a remote heat 
of said thermal insulation panel between said first exchanger and returned to said tank. 
and second positions whfie maintaining the parallel 6. A combined solar energy collector, fluid chiller, and energy storage system as in claim 1 and further 
thermal insulation panel said panel in said second of the wall of %id tank, said wall being expos- 
position forms with the other surfaces of said tank able to an air space and said insulating panel being mov- 
an insulating enclosure for said liquid. able to allow regulation of heat transfer between said 
2. A combined solar energy collector, fluid chiller, liquid and said air space. 
What is claimed is: 
1. A combined solar energy collector, fluid chiller, 
panel to Or from a 20 
and energy storage svstem 
between said collector and said 30 comprising a second insulating panel corresponding to a 
and energy storage system as in, claim 1 and further 35 * * * * *  
40 
45 
50 
55 
65 


Combined solar collector and energy storage system

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