CA1089732A

CA1089732A - Solar panel

Info

Publication number: CA1089732A
Application number: CA303,510A
Authority: CA
Inventors: Heather J. Hall
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-05-16
Filing date: 1978-05-16
Publication date: 1980-11-18

Abstract

This invention relates to a novel solar panel for collecting and transmitting solar energy to the inside of a building or room; the panel also acting as an insulation panel when desired. The panel is used in conjunction with a transparent window having a window frame therearound and comprises an insulating portion, a highly absorbtive, emissive film covering one surface of the insulating portion, and a securing means which is adapted to adjustably secure the top of the panel to the window and the distance therebetween. The panel can be easily adjusted to compensate for different solar altitude angles thereby achieving maximum efficiency. It is inexpensive to manufacture and quite efficient.

Description

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BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION
This invention relates to solar energy and more particularly, to a device suitable for use for collecting solar energy and transforming the solar energy directly into heat, the device also being suitable for use as an insulating panel when mounted on the inside of a window.
The device may be used as a solar collector panel on the inside of a window to act as a primary or secondary heating unit for a room or a bu;lding.
These devices are particularly useful when used either as a primary source of heat or as a secondary source of heat for a room or a building. They are not however, intended to fully replace conventional heating systems for homes or buildings in particularly cold climates but may be used inthese cold climates as a secondary source of heat to reduce the requirements of the primary source of heat and thus reduce overall fuel costs for heating the home or building. ;~

The cost of heating buildings and particularly, home heating costs have escalated rapidly during the past few years. In addition to the increasing cost, there is a genuine concern in many countries concerning the availability of conventional fuels for heating purposes. While expert opinion varies, it is acknowledged that new fuel sources must be found to either supplement or replace conventional heating systems in order to maintain present life styles.
Science has therefore begun to look to alternate fuel sources over the past few years and one particular area -1- ~ , - ~ , .

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1 to which much attention has been directed is the sun. If man were able to harness the energy produced by the sun and transform it to usable heat, many of the problems associated with con-ventional systems would either be reduced or eliminated.
However, it is recognized that the system which will convert solar energy to usable heat must be not only efficient, but also economical. Much work has been done in designing larger scale solar panels for use with large buildings and research is also progressing in the area of alternate systems for use in the home.
Recently, various devices have been proposed which collect solar energy emitted by the sun and transform this enexgy into heat which may be used to heat the inside of a building or a room. Some of these devices may also act as insulators to prevent loss of heat from the room or building and are affixed to either the exterior or the interior of the window.
An example of these devices is shown in United States Patent Number 4,043,316 granted to Arent on August 23, 1977.
This device, mounted on the exterior of the window, uses a first panel which in the closed position, protects and insulates the lower part of the window. In the open position, the reflective inner surface of the first panel member reflects the rays from the sun into the lower window unit which has a solar heat collector positioned inwardly thereof.
A different device is shown in United States Patent 4,002,159 granted to Angilleta on January 11, 1977. This device uses a venetian blind with a heat-absorptive surface on one side of the slats which distributes the solar heat into the ambient air of the room. The air, moving into the ~ 0~3'73~
1 air space in the venetian blind by natural convection, is warmed by the heated surface within the blind. The opposite sides of the blinds carry a reflective surface which when turned towards the sun, reduce heat entry into the room.
Other devices for use as heating panels are shown in United States Patent Numbers 3,875,925 (Johnston), 4,051,832 (Stelzer), 2,931,578 (Thompson), 4,058,109 (Gramm) and 4,014,313 (Pederson).
However, all these devices of the prior art have proven to be both cumbersome and expensive. Also, the prior art devices which are affixed to the exterior of the windows necessarily require a considerable amount of time for installation, repair and adjustment. Considering that many ~
of the windows in homes may be a considerable distance above -the ground, the devices which are secured to the exterior of these windows require a great deal of attention for installation and adjustment. Further, many of these devices required expensive heat collector panels in addition to the solar panels which increases the cost of the unit dramatically.
A further problem associated with the devices of the ;
prior art is that no means is provided to adjust the angular orientation of the solar panel to compensate for different solar altitude angles which occur at different latitudes and which also vary for different times of the year. In order to achieve maximum efficiency of the device, it should be adjusted to compensate for differing solar altitude angles.

SUMMARY OF THE INVENTION
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Accordingly, it is an object of the present invention to at least partially overcome thesie disadvantages by providing 1 a simple yet efficient solar panel which produces heat or which when placed in the closed position, insulates a window. It is a further object of this invention to provide a simple means for attaching the panel to the window which may be easily adjusted to compensate for different solar altitude angles.
It is a further object of this invention to produce an efficient solar panel which is inexpensive to manufacture and which acts as a primary or secondary source of heat in the room, thereby effectively reducing the reliance upon conventional heating systems to heat a house or builaing and therefore, reducing the cost of these conventional systems.
To this end, in one of its aspects, the invention provides a solar panel for use in conjunction with a transparent window having a window frame therearound,said panel comprising:
(i) an insulating portion;
(ii) a highly absorbtive, emissive film covering one surface of said insulating portion; and (iii) a securing means adapted to adjustably secure the top of said panel to the window ~rame and the distance therebetween.
In another of its aspects, the invention further provides a solar panel for use in conjunction with a transparent window having a window frame therearound, said panel comprising:
(i) a rectangular, insulating portion comprising a rigid, fibre board;
~ii) a black, polyethylene film secured to said insulating portion and covering a first surface of said board, with a plurality of perforations through the surface of said film;

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z 1 (iii) a frame portion about the peripheral edges of said f ilm and said insulating portion; and (iv) a securing means adapted to adjustably secure the top of said panel to the window frame and the distance therebetween, said securing means comprising a cord, a series of rings secured to said cord at predetermined positions along its length, and a hook secured to the window frame at the upper portion thëreof, said rings adapted to hook onto said hook.

' 1 0 BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of the invention will appear from the following description taken together with the accompanying drawings in which:
FIGURE 1 is a perspective view of the panel attached to the window frame.
FIGURE 2 is a side sectional view of the present invention.
FIGURE 3 is a side sectional view of the panel attached to the window frame.

DESCRIPTION 0~ THE PREFERRED EMBODIMENT
Reference is first made to figure 1 which shows a perspective view of the solar panel of the present invention attached to the interior of a window (and its frame). As shown in figure 2, the solar panel 10 comprises an insulating portion 12, and a film 14 disposed on the surface of the insulation portion adjacent the window 24. If desired, a frame 18 may be placed around the peripheral edges of the film 14 and the insulating portion 12.
The insulating portion 12 is preferably rigid in structure and may be made of any material which acts as a ,~ ~0~ 32 1 barrier to the transfer of heat across it. An example of a suitable material is fibre board. The film 14, as explained hereinafter, must have a high absorbtion rate for heat and should also demonstrate good emissivity. In the preferred embodiment, the film 14 carries a series of perforations 16 through it. The frame 18 may be constructed of any well-known material such as plastic or wood.
In use, the solar panel 10 is placed with its lower end 20 on a window sill 22 of the window 24 and displaced a short distance therefrom. The upper portion of the panel 10 is secured by the securing means 26 at a predetermined distance from the window 24 so that the angle between the window 24 and the solar panel 10 may be easily adjusted.
Securing means 26 may be of any construction provided that it secures the upper portion of the panel 10 at a specified distance from the window 24. It should however, be easily adjustable so that when desired, the distance between the upper part of the panel 10 and the window 24 may be easily adjusted and therefore, the angular displacement of the panel 10 from the window 24 may also be adjusted.
In a preferred embodiment of this invention, the inventor has provided a simple yet efficient securing means which utilizes inexpensive and basic household items. An example, as shown in the figures, uses a cord or wire 28 which is, at one end, attached to the upper part of the frame 18. A series of rings 30 are secured to the cord at predetermined distances and a hook 32 is provided on the upper part of the window frame 40 upon which a preselected ring 30 is hooked. It is understood that the components of the securing means may be replaced by any similar means within 3'73Z

1 the scope and breadth of the present invention. Thus, in order to secure the panel lo at a selected angle with respect to the window 24, one of the rings 30 is secured to the hook 32 to achieve the desired posi~ion.
Referring now to figure 3, the rays 34 of the sun impinge upon the window 24 and are transmitted through the transparent window ~4 and are absorbed on the surface of the film 14, thus heating the panel 10. The air (shown by arrows 36) within the room inside of the window 24 will flow in a counter-clockwise direction (as shown in figure 3) striking first the upper inside portion of the window 24 and downward along the inner surface of the window 24. The air then contacts the panel 10 at the lower portion thereof and is heated by the heat stored in the panel 10. As the air is heated, some of it will flow upwards as indicated at 38 and some continues along the surface of the panel 10 as shown by arrows 42. As this air is being heated, it rises to fill the room with warm air.
During night or at other times when the sun may be obscured, the panel is closed, that is, brought to a vertical position adjacent the window, and acts like an insulation barrier preventing heat loss from the room.
The black polyethylene film 14 may carry a plurality of perforations 16 through its surface. These perforations 16 are extremely small and are of the size of pin-holes. When constructed in this manner, the inventor has found that the film 14 clings to the surface of the insulating portion 12 thereby increasing the amount of heat absorbed by the panel.
The black film 14 creates an excellent absorbing material and increases the "greenhouse effect" in combination with the glass of the window 24.

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1 In order to provide maximum efficiency of the solar panel, attention must be had to the distance that the top of the panel 10 is displaced from the window 24 which of course, controls the angle between the panel 10 and the window 24. This angle, shown as 44 in figure 3, -~
is referred to as the angle of recline and is dependent . -upon the solar altitude angle for that particular day and for the latitude of the window. This angle is controlled by the securing means and by attaching different rings 30 to the hook 32, the angle may be easily and quickly adjusted.
In order to calculate the correct length of the cord and therefore, to control the angular displacement of the panel from the window, the following formula may be used:

L = Sine 21 a x H x 2 , wherein L represents the distance from the top of the solar panel 10 to the window 24 at the point of the height of the panel, that is, at hook 32;
a represents the solar altitude angle at the latitude of the window (which is the same as angle 44 shown in figure 3);
H represents the height of the panel 10.
Diagrammatically, the formula may be represented as follows:

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3 0 ~\ I~H

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1 ~hus, L is calculated for each solar altitude angle which of course depends upon the day of the year. This calculation is done for a predetermined number of lengths ~
and rings 30 are attached to the wire 28 at these distances. :
Each of the rings may then be identified as to date and/or hour of the day and the operator may easily adjust the panel by identifying the time period and adjusting which ring is hooked unto hook 32.
An example of the calculation of the solar altitude, angle is shown in table 1. These calculations were done for a latitude of 50 for various times of the day.

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1 In a preferred embodiment of the invention, the solar panel 10 may be constructed as follows. A piece of one-half inch (thickness) fibre board is cut to correspond to the size of the window and the back face of the board is painted. A
sheet of polyethylene is cut to cover the board and is stapled to the unpainted face of the board. The film may, in the preferred embodiment, be affixed to the board in the warmed state.

The film is then perforated at, preferably, one inch -spacing in a grid pattern. These perforations allow the heat to dissipate from within the panel which occurs when the film is exposed to the rays from the sun. Without the perforations, the polyethylene film would tend to expand and the perforations allow the film to lie flat on the fibre board. A frame is placed around the board and if desired, the rear surface may be decorated to suit the individual's taste.
- When ready to be used, the solar panel is placed in a window which receives sunlight with the film facing the window. The lower edge 20 of the panel 10 is placed contiguous with the window sill 22 so that no space exists therebetween.
The lower edge 20 is placed at a distance spaced from the window 24, preferably, two inches and the panel is secured by the securing means 26 at a predetermined angle from the vertical window.
The angle at which the panel 10 is placed with respect to the window 24 is dependent upon the solar altitude angle and the particular day and month of the year. For most efficient operation, the plane of the film 14 should be normal to the solar altitude angle. Maximum heat will :, , , , ' ', ' , lVB9'73Z

1 be given off when the solar azimuth angle is zero, that is, when the solar azimuth angle is at a 90 angle to the wall - i of the building or the window.
Maximum solar gains occur when the solar altitude is between 30 and 35 and the wall azimuth is close to zero. Virtually all types of glass used today are completely opaque to longwave radiation emitted by surfaces at temperatures below 250F. This characteristic produces the "greenhouse effect" by which solar radiation which enters through a ~lO window, is trapped.
When radiation is absorbed by a surface within the room and then emitted as longwave radiation, the heat cannot escape from the room because the window is opaque to all radiation beyond 3.0 microns. This is equally applicable to either single or double pane glass which transmits from 85 to 90 percent of the incident radiation between 0.3 and 3.0 microns.
The film 14 may be made of any suitable material and polyethylene has proved effective as the preferred embodiment.
Polyethylene has a rate of thermal conductivity of 0.19 BTU/(hr)(sq.ft)(F/ft) and a specific gravity of about 0.91 to 0.925. Heat distortion of the polyethylene does not occur until 175 to 200F and carbon-filled grades of polyethylene are both resistant to sunlight deterioration and weathering.
The high heat absorbtion rate of the black poly-ethylene is due also to the bla~c colour and also to the carbon content which attracts the solar radiation. The high emissivity of the heated black polyethylene film is due to the "greenhouse effect" and the smooth surface of the film.

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TEMPERATURE TESTS
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A panel according to the preferred embodi~ent of this invention was constructed and placed in the window facing south-west of a house in Kilbride, Ontario, Canada. The panel was constructed of wood fibre board with a sheet of black polyethylene over one surface. The panel was about 24" x 48" in size and was placed in the window with the bottom of the panel approximately 2" from the window and the panel inclined inwardly at an angle of 15 to the vertical window.
~`10 A Taylor thermometer was used to read the temperature and the air coming off the panel was tested at periodic intervals, usually every 15 minutes. In this test, the black polyethylene film was not perforated. Subsequent tests have established that no differences were observed with respect to the air temperature in the presence or absence of perforations. During the experiment, the temperature of the panel itself was in excess of 130F when the temperature of the air coming off the panel was 120F.
For this experiment, the building (and window) line was N 44 W at north latitude 50 (calculated~. The readings were taken at 2 p.m. with the solar azimuth angle at 209 and the solar altitude of 15.~ The experiment was done on January 18, 1978.
The follcwing results were obtained.

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TEMP.OF COLD TEMP. OF AIR TEMP. OF AIR TEMP. OF
AIR AT WINDOW ON COLLECTOR IN ROOM OUTDOOR AIR
TIME (INSIDE)(F) PANEL (F) (9F) (F) , ._ _ _ _ _ _ _ . . . . _ 1 0 3 OAM 68F 74~E~ 70F 18F

1l45 68F 78F 70F 22F

12 Noon 68F 82F 71F 22F
1215pM 68F 92F 72F 22F

45pM 68F 100F 76F 22F .
00pM 68F 104F 78F 22F
115pM 68F 104F 78F 22F

200PM 68F 110F . 79F 22F
215pM 68F 112F 80F 22F
, _ .

~20300PM 68F 115F 80F 22F .
315PM 68F 110F 80F 22F .

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-1 During the experiment, it was note~ that the film was stretched tight at the lower or room temperature but expanded considerably when heated by the solar rays.
Without the perforations, there was a build-up of warm air between the film and the fibre board causing a billowing effect of the film. When the film was perforated, it lay flat on the fibre board.
Two observations were made during the experiment.
Later on during the evening when the panel was closed, it was ~10 noted that the temperature of the room was higher than it had been on similar days in the past, indicating that the panel was acting as an insulator when in the closed position.
The second observation noted was that it was not until approximately 2:30 PM that the panel was in full sunlight.
At all other times during the day, the panel was either partly or completely shaded. However, it was noted that the panel was warm before the sun shone on it due to the reflection of the solar rays from the snow.
For the purposes of this experiment, the solar azimuth angles and the solar altitude angles were calculated from the Carrier System Design Manual. This system may be used to calculate both the solar altitude angle and the solar aæimuth angles for a specific latitude and a time of day and by means of the formula as explained hereinbefore, the angle of the solar collector panel and the length of the cord of the securing means is determined.
From this experiment, it is clearly seen that the temperature of the air in the room is raised significantly using just one panel. As an adjunct to conventional heating systems, the use of the panel will, over a period 1~18~73~

l of time, reduce the reliance upon the conventional heating systems and therefore, reduce the heating costs for the consumer. The panel is quite inexpensive to manufacture and exhibits good durability. No other source of heat is required other than the sun and the panel may be easily used by even the most inexperienced of consumers.
The panels may be placed in any desired window of the house depending upon of course, the direction faced by these ~indows. More than one panel can be used in a single window if desired, provided that a second sill is provided upon which the base of the second panel can rest. Also, within the scope of the present invention, the warm air coming off the panel may be directed in a predetermined direction by any suitable means which might include a chimney apparatus, a chute or a co-operating directional tunnel or tube.
Although the invention describes and illustrates a preferred embodiment of the invention, it is to be understood the invention is not restricted to this particular embodiment.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An indoor, passive, lightweight and portable window unit solar heat collector and insulating panel for use in con-junction with a vertically disposed transparent window having a window frame therearound, said panel comprising:
(i) an insulating portion;
(ii) a flat, highly absorbtive, emissive film covering one surface of said insulating portion;
(iii) a securing means adapted to adjustably secure the top of said panel to the window frame and to adjust the distance therebetween; and (iv) a frame portion about the peripheral edges of said film and said insulating portion, the lower portion of said frame adapted to be contiguous with the lower portion of the window frame;
whereby, when the panel is to act as a solar heat collector, the panel is positioned such that the film is adjacent said window and the upper portion of the panel extends acutely rearwardly from the window at a predetermined angle and is retained at the angle by the securing means so that cool air which passes downwardly along the inside of the window will be deflected upwardly along the inside surface of the panel and the cool air will be heated by heat emitted by the panel after it has been struck by solar radiation; and when the panel is to act as an insulating panel, the panel is positioned such that the film is adjacent said window and both the upper and lower portions of the panel are contiguous with the respective upper and lower portions of the window frame.

2. A solar panel as claimed in claim 1 wherein said insulating portion consists of a piece of rigid, fibre board.

3. A solar panel as claimed in claim 1 wherein said securing means comprises a cord secured to the upper part of the frame portion, a series of rings secured to said cord along its length, and a hook secured to the window frame at the upper portion thereof, said rings adapted to hook onto said hook.

4. A solar panel as claimed in claim 1 wherein said film is a black, polyethylene film.

5. A solar panel as claimed in claim 1 wherein said film carries a plurality of small perforations through its surface.

6. An indoor, passive, lightweight and portable window unit solar heat collector and insulating panel for use in conjunction with a vertically disposed transparent window having a window frame therearound, said panel comprising:
(i) a rectangular, insulating portion comprising a rigid, flat-topped, fibre board;
(ii) a flat, black, polyethylene film secured to said insulating portion and covering a flat first surface of said board, with a plurality of perforations through the surface of said film;
(iii) a frame portion about the peripheral edges of said film and said insulating portion the lower portion of said frame being adapted to be con-tiguous with the lower portion of the window frame;
(iv) a securing means adapted to adjustably secure the top of said panel to the window frame and the distance therebetween, said securing means com-prising a cord, a series of rings secured to said cord at predetermined positions along its length, and a hook secured to the window frame at the upper portion thereof, said rings adapted to hook onto said hook,

Claim 6 continued .....

whereby, when the panel is to act as a solar heat collector, the panel is positioned such that the film is adjacent said window and the upper portion of the panel extends acutely rearwardly from the window at a predetermined angle and is retained at the angle by the securing means so that cool air which passes downwardly along the inside of the window will be deflected upwardly along the inside surface of the panel and the cool air will be heated by heat emitted by the panel after it has been struck by solar radiation; and when the panel is to act as an insulating panel, the panel is positioned such that said film is adjacent said window and both the upper and lower portions of the panel are contiguous with the respective upper and lower portions of the window frame.

7. A solar panel as claimed in claim 6 wherein each ring carries identifying indicia to indicate on what date said ring should be secured to said hook.

8. A solar panel as claimed in claim 6 wherein each ring carries identifying indicia to indicate at what hour of the day, said ring should be attached to said hook.

9. A solar panel as claimed in claim 6 wherein each ring carries identifying indicia to indicate on what date and at what hour of the day, said ring should be attached to said hook.