Title of Invention

AN IMPROVED HEATING DEVICE USING SOLAR ENERGY

Abstract The present invention relates to a device that utilizes solar energy for cooking / heating. The conventional solar energy based cooking devices such as box type solar cooker suffer from the drawback such as substantial thermal mass of cooking leading to prolonged timings for cooking, temperature reductions in transferring heat from absorber to vessel, convection losses from glazing. Further bulkiness and weight of these cookers pose limitations on the mobility and handling the same effectively in the sunlight. The judicious use of two containers and disposition of the said containers so as to form air spaces and the containers provided with respective glazing provides a portable, compact, light weight, easily installable solar energy based heating / cooking device having substantially reduced thermal mass obviating the need for tracking mechanism / moving the device and separate absorber, yet effectively operable during early hours of the day when the sun"s ray are slanted.
Full Text FORM - 2
THE PATENTS ACT, 1970
(39 OF 1970)
COMPLETE SPECIFICATION
(See Section 10)
TITLE OF INVENTION
"An Improved Heating Device Using Solar Energy"
(a) Amit S Gadkari
(b) residing at
RL 66 Milap Nagar, MIDC, Dombivli 421 203 State of Maharashtra, India
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.

Field of Invention
The present invention relates to a device that utilizes solar energy for cooking / heating.
Background of Invention
Solar energy is used as one of the sources for heating and further cooking food. Various systems to harness the solar energy are being developed over the period of time. The solar cooking devices are categorized on the way solar energy is captured and further utilized by virtue of geometry of the system. Generally there are two types of cooking devices viz. box and concentrating type.
Conventional box cookers have a black absorber box with high absorptivity covered with glass glazing. The absorber box is enclosed in another box with fiberglass insulation in between. The cooking vessels are plated black and placed on the absorber box for cooking. Several solar cooking devices are reported in the literature they are as follows:
United States Patent 4077391 discloses portable solar cooker and the solar panel used. It comprises an internally insulated metal housing having an oven compartment for slidably receiving a cooking tray. A plurality of adjustable sun reflectors arranged on the top of the housing direct the sun's radiation into a heat-generating area. The heat-generating area is insulated by the air space formed by two transparent windows. Beneath the inner window and directly above the oven roof are a plurality of heat generating strips formed from fibrous insulation material covered by thin sheets of black foil. A series of spacers maintain spacing between the strips. The solar panels comprising the windows, heat generators and an appropriate heated chamber form a part of the invention.
United States Patent 4662354 discloses Heating And/Or Cooking Device Using Solar Energy. It comprises a solar collector connected via an inclined heat pipe to a heat store. A thermal load, in the form of a heat-emitting plate, either is in direct contact with the solar collector or the heat store or is connected to that store via


another heat pipe. The emission of heat can be controlled by changing the angle of inclination of the last-mentioned heat pipe or of the entire unit.
United States Patent 4220141 discloses portable solar cooker. It comprises an insulated housing with an oven compartment enclosed therein and associated reflector elements is adapted for cooking with the housing and oven compartment in a tilted or level position. When employing only the tilting mode for tracking the sun, reflecting panels are removably attached to the top of the cooker housing. When there is a need to maintain the oven compartment level while tracking the sun during the cooking operation, the reflecting panels are removably mounted on a pivotal frame connected to a telescoping strip assembly which, in turn, is removably mounted on the topside of the cooker housing.
United States Patent 4442828 discloses portable type solar heat cooker assembly. It includes a cooking glass tube comprising an outer bottomed glass tube and an inner bottomed glass tube coated with a selective absorption film showing a high absorptivity in the solar radiation spectrum zone and a low absorptivity in the heat radiation spectrum zone. The inner tube is coaxially inserted into the outer tube and hermetically sealed together at their open ends, with a space there between being evacuated to vacuum. A case is provided to open on hinges and to receive the cooking glass tube at its central portion. A curved reflector is bisymmetrically provided on the case, which forms a reflex mirror for the solar rays when the case is opened. A tillable stand attached to the outside of the case is provided to support the case in an inclined state.
United States Patent 4236508 discloses solar cooker and method of assembly. A method of assembling from kit components a solar oven and in so doing, teaching the assembler the principals involving insulation, reflection, solar ray conversion to heat, temperature conservation and the fine art of cookery.
United States Patent 4913130 discloses solar cooker assembly. It comprises a circular and convex Fresnel lens having its convex side facing either upward or downward, a protective frame unit rigidly fitted to the periphery of said Fresnel lens,


a support unit for swingably supporting said Fresnel lens so that the elevation and the aximuth of the lens can be freely chosen without restriction and a cooking unit located at the focal point of said Fresnel lens.
United States Patent 20040134485 discloses solar cooker concentrator of the box type, using cpc-type Optics. It uses compound Parabolic Concentrator type optics comprising a box, inside which all its accessories and cooking utensils can be carried; the box being essentially made of plastic compatible with the production of complicated curves characteristic of the referred optics. The present invention includes a version in which electrical energy is used as backup for days without sunshine. Its application extends to other areas beyond the cooking of foodstuffs, in particular to the pasteurisation of water, milk and other products and its usage as a drying system.
United States Patent 4083357 discloses solar cooker. It consists of a parabolic trough reflector and having support legs attached at the approximate center of gravity of the reflector and oven assembly. The reflector longitudinal supports serving to hold a cooking oven consisting of a bottom of transparent plastic and a detachable top made of insulation and lined inside with a reflective material. The items to be cooked are supported inside the oven by means of a skewer or a skewer supported pan. The reflector assembly also having an aiming device mounted on it's perpendicular support to assure reflector focus by means of shadows
United States Patent 4262660 discloses a portable, knock down, solar cooker having a box-shaped supporting body to which an expandible parabolic reflector and associated solar oven can be readily assembled and disassembled without the use of any hand tools, and in the disassembled position the component parts can be readily stowed within the box shaped supporting body. The solar cooker also includes a foldable parabolic reflector associated with a solar oven which has a circumscribing shield to define a confined air space about the solar oven in the erected position to enhance the efficiency thereof.
United States Patent 5090399 discloses solar cooker with a fold-up parabolic reflector comprising two stacks of reflecting flexible strips unfoldable so as to form a


reflector. Strips of each stack are connected to one another by means of a pliable band fastened to the back of each of the strips. The reflector comprises a grid articulated on the end of a support which can be fastened in the extension of a mount by means of a simple maneuver. The grid is shaped in such a way that it can be put into the position of use on its support simply as a result of rotation.
United States Patent 20060000501 discloses solar oven that uses a solar radiation collection system and a photovoltaic heating system. The solar radiation collection panels heat the oven from the top. The photovoltaic system with its controls provides heat from the bottom. The system consists of a main primary radiation reflector at the top of the oven. The photovoltaic system consists of a solar panel charges the battery which in turn provides power to the heating element. The heating element is controlled to provide heat at the bottom for specified time limits and/or the specified amount of heat required for specific cooking or heating. A car electric generating system could also be used to provide power to the heating element. The system is design to be stationary or portable.
United States Patent 5524610 discloses solar powered/multiple fuel cooking device. It cooks food by using solar radiation, charcoal or similar solid burnable fuels, heating candles, gas, or electricity. The cooker includes a base and solar reflectors along opposite sides of the base. The reflectors pivot with respect to the base to focus solar radiation along an axis extending parallel to the reflectors. Food is supported along or adjacent the axis for cooking. A grate within the base supports charcoal or similar fuels and a gas burner and electric heating element are also supported by the base for use in cooking. A container can be mounted within the base for holding food to be cooked.
US patent 5,195,504 modifies the basic box cooker design with the judicious use of reflectors and the use of oil to reduce thermal losses. However this greatly increases the thermal capacity and weight of the cooker.
US patent 5,139,010 uses reflectors with the objective of heating the dark bottom and back wall of the absorber where a heating element present maintains a constant temperature of the cooker.


The panel cookers such as 'Cookit' from Solar Cookers International and the 'Hotpot' from Solar Household Energy use a semi concentrating arrangement for a pot type vessel. However they need glass vessel or consumable transparent bags for the greenhouse enclosure, else wind could have a substantial impact on cooking time. Another aspect of consideration is that some dishes need a more flat vessel for cooking compared to a pot.
Thus the study of the related prior art reveals several technological gaps such as:
s Substantial thermal mass of cooking systems leading to prolonged timings for
cooking, particularly in a box type cooker
s Use of fiber glass insulation
S Substantial temperature reductions in transferring heat from absorber to
vessel
S Substantial convection losses from glazing
s Bulkiness and weight of these cookers pose limitations on the mobility and
handling the same effectively in the sunlight.
S Considerable space requirement for concentrating cookers
S Tracking requirement on a continuous basis for concentrating cookers
S Substantial initial capital cost of the concentrating cookers. Adoption has been
limited due to their initial capital cost,
S difficult to manufacture for unskilled labor,
S need continuous attention for tracking as well as likely to be unsafe due to the
concentration of solar radiation
Necessity has constantly been felt to develop a portable, compact, light weight, easily installable solar energy based heating / cooking device having substantially reduced thermal mass obviating the need for tracking mechanism / moving the device and separate absorber, yet effectively operable during early hours of the day when the sun's rays are slanted.
Summary of the Invention
The main object of the invention is to provide a solar energy based heating / cooking device with substantially reduced thermal mass.


Another object of the invention is to provide the solar energy based heating / cooking device that obviates the need of separate absorber.
Another objective of the invention is to provide the solar energy based heating / cooking device without tracking means.
Yet another object of the invention is to provide the solar energy based heating / cooking device that is effectively operable during early hours of the day when the sun's rays are slanted.
Yet another object of the invention is to provide the solar energy based heating / cooking device with means to substantially reduce convection loss.
Yet another object of the invention is to provide compact solar energy based heating / cooking device.
Another object of the invention is to provide solar energy based heating / cooking device that provides visibility to the food being cooked.
Yet another object of the invention is to provide solar energy based heating / cooking portable device with substantially lower weight.
Another object of the invention to provide solar energy based heating / cooking device that regains original temperature faster in the event of opening the cooker.
Thus in accordance with the invention the device comprises of
A first container / housing comprising
reflective coating / material provided on the inner surface/s that are formed by walls of the container; protrusion / support provided all round the periphery of the said inner surface of the walls of the said container; a glazing to cover and allow solar radiation inside the container; rubber lining between the surface of the glazing facing the container and the container edges so as to form airtight seal;


a second container upper portion of which is covered with a removable transparent glazing wherein all the interior and surfaces of the said second container are coated / painted / provided with absorptive material; wherein
the said second container is adapted to accommodate / house / enclose and rest on the said protrusion / support of the said first container to define first air space / zone / cavity defined by the top surface of the said glazing of the said second container, bottom surface of the said glazing of the said first container and wall/s of the said first container; wherein
the second air space / zone / cavity is defined by the bottom surface of the said second container, bottom of the said first container and wall/s of the said first and second container; wherein
the said first air space / zone / cavity and the said second space / zone / cavity is separated by the said protrusion / support provided all round the periphery of the said inner surface of the walls of the said container.
Description of the Invention
Features and advantages of this invention will become apparent in the following detailed description and the preferred embodiments with reference to the accompanying drawings.
Figure 1 Schematic of the device (Sheet 1)
Figure 1 illustrates sectional front view of the device. It comprises of a first container 22, preferably with a substantially box shaped body shell but not limited to it. The reflective coating / material 5 (not indicated) is provided on the inner surfaces formed by walls 6 as well as on the bottom surface 7 of the container 22. The second container 4, preferably made of high conductivity material such as aluminum but not


limited to it, is housed inside the first container 22 and is rested on the insulated support / protrusion 3 provided all round the periphery of the said inner surface of the walls of the said container 22. In one of the embodiments the said container 4 is divided in plurality of compartments. In another variant of this embodiment, the said compartments are adjustable to desired volume. A glazing 21 is provided on the container 22 to cover and allow solar radiation inside the container. Further, rubber lining (not shown) is disposed between the surface of the glazing facing the container and the container edges so as to form airtight seal. The container 4 is provided with highly absorptive coating with low emissivity on the outside as well as the inside surfaces (not indicated). The container 4 is covered with a removable transparent glazing 2. This glazing may have a low emissivity coating or may be made of a low emissivity transparent material. The first air space / zone / cavity 15 is defined by the top surface of the glazing 2 of the said second container 4, bottom surface of the glazing 21 and wall/s 6 of the first container 22. The second air space / zone / cavity 9 is defined by the bottom the said second container 4, bottom 7 of the first container and walls of the said first container 4 and wall/s of the said first container 22 as shown in the figure. The said first air space / zone / cavity 15 and the said second space / zone / cavity 9 is separated by the said protrusion / support 3 provided all round the periphery of the said inner surface of the walls of the said container. In one of the embodiments the said first air space 15 is divided in plurality of compartments. Further in yet another embodiment the said second air space 9 is divided in plurality of compartments. As shown in the top and the front view of the Figure 1, reflective rotatable surfaces 23, 24, 25 and 26 are hinged to the top edges of the said container 22 near the said glazing 21. As indicated in the Figure 1, the height of the adjacent reflective surfaces 23 and 24 is substantially equal. The said reflective surfaces can be rotated at a desired angle so as to reflect the solar radiation towards the said glazing 21. This arrangement of the reflective surfaces facilitates effective operation of the device during early hours of the day when the inclination of the sun rays is higher
In one of the embodiments the said insulated support 3 is removably attached to the said all round the periphery of the said inner surface of the walls of the said container 22. In yet another variant of this embodiment the said insulated support is affixed to


the said all round the periphery of the said inner surface of the walls of the said container 22.
In one of the embodiments the inner surface of the said container 22 are provided with protrusion/s such that the said protrusion/s touches the surface of the second container 4 thereby creating compartments in the said second space 9. In yet another variant of this embodiment one or plurality of lamina is disposed in the the said second space wherein one end of the lamina is in contact with the said inner surface of the said container 22 and other with the said outer surface of the container 4 so as to create compartment/s.
In yet another embodiment one or plurality of lamina is disposed in the said first air space 15 wherein in one end of the said lamina is in contact with the lower surface of the said glazing 21 and other end in contact with the said top surface of the glazing 2 so as to create compartment/s.
In one of the embodiments the body shell comprises of an optional insulation such as, but not limited to, expanded foam, plywood layer, and an outer environmental protective shell G1 sheet. In another variant of this embodiment reinforced fibreglass is used for the body shell.
In yet another embodiment the glazing 2 is provided with a low emissivity coating on the surface facing the outer glazing 21 or is made of low emissivity material.
In another embodiment the outer glazing 21 is connected to the box 22 with the hinge either directly or using an aluminum extrusion frame.
In yet another embodiment the outer glazing 21 is a double pane glazing with the outermost glass being low iron solar glass and the other being a low E glass.
In yet another embodiment the said glazing 2 is replaced with a partially opaque or translucent cover coated with material exhibiting high absorptivity and low emissivity on the outside surface as well as a high emissivity on the inside surface wherein the said lamina 2 is dimensioned to press fit the said second container 4 open end.


In yet another embodiment the vertical surfaces of the said first container 22 is openable to facilitate easy placement and removal of the second container 4.

I claim
1. A device for heating/ cooking using solar energy comprising a first container comprising
reflective coating / material provided on the inner surface/s that are formed by walls of the container; protrusion / support provided all round the periphery of the said inner surface of the walls of the said container; a glazing to cover and allow solar radiation inside the container; rubber lining between the surface of the glazing facing the container and the container edges so as to form airtight seal; reflective rotatable surfaces provided at each of the top edges of the said container disposed in the vicinity of the said glazing;
a second container upper portion of which is covered with a removable transparent glazing wherein all the interior and surfaces of the said second container are coated / painted / provided with absorptive material; wherein
the said second container is adapted to accommodate / house / enclose and rest on the said protrusion / support of the said first container to define first air space / zone / cavity defined by the top surface of the said glazing of the said second container, bottom surface of the said glazing of the said first container and wall/s of the said first container; wherein
the second air space / zone / cavity is defined by the bottom surface of the said second container, bottom of the said first container and wall/s of the said first and second container; wherein
the said first air space / zone / cavity and the said second space / zone / cavity is separated by the said protrusion / support provided all round the periphery of the said inner surface of the walls of the said container.


2. A device for heating/ cooking using solar energy as claimed in claim 1 wherein the first container is provided with insulation such as expanded foam, plywood and an outer environmental protective shell of Gl sheet.
3. A device for heating/ cooking using solar energy as claimed in claim 1 wherein the glazing of the said second container is made of low emissivity material / low emissivity coating on the surface facing the glazing of the said first container.
4. A device for heating/ cooking using solar energy as claimed in claim 1 wherein the said first air space and/ or second air space is divided in two or more compartments.
5. A device for heating/ cooking using solar energy as claimed in claims 1,2 wherein the glazing of the said first container is a double pane glazing with low iron solar glass and / or low emissivity glass.
6. A device for heating/ cooking using solar energy as claimed in claim 1 wherein the said reflective rotatable surfaces are disposed on the top edges of the said first container such that the two adjacent reflective surfaces have substantially equal height.
7. A device for heating/ cooking using solar energy as claimed in claims 1, 3 wherein the said glazing of the second container is replaced with a partially opaque or translucent cover coated with material exhibiting high absorptivity and low emissivity on the outside surface as well as a high emissivity on the inside surface wherein the said glazing is dimensioned to fit the said second container open end.
8. A device for heating/ cooking using solar energy as claimed in claim 1 wherein one of the vertical faces of the said first container is openable to facilitate easy placement and removal of the second container.


A device for heating/ cooking using solar energy as claimed in claims 1, 2, 4 wherein the inner surface of the said first said container is provided with protrusion/s such that the said protrusion/s are in contact with the outer surface/s of the second container thereby creating compartments in the said second space.
A device for heating/ cooking using solar energy as claimed in claims 1, 2, 4,
9 wherein the said insulated support is removably attached / affixed to all
round the periphery of the said inner surface of the walls of the said first
container.
A device for heating/ cooking using solar energy as claimed in claims 1, 4, 9,
10 wherein one or plurality of lamina is disposed in the said second space
wherein one end of the lamina is in contact with the said inner surface of the
said first container and other with the said outer surface of the said second
container so as to create compartment/s.
A device for heating/ cooking using solar energy as claimed in claims 1,4, 9-
11 wherein one or plurality of lamina is disposed in the said first air space
wherein one end of the said lamina is in contact with the lower surface of the
said glazing of the first container and other end in contact with the said top
surface of the glazing of the second container so as to create compartment/s.

Abstract
The present invention relates to a device that utilizes solar energy for cooking / heating. The conventional solar energy based cooking devices such as box type solar cooker suffer from the drawback such as substantial thermal mass of cooking leading to prolonged timings for cooking, temperature reductions in transferring heat from absorber to vessel, convection losses from glazing. Further bulkiness and weight of these cookers pose limitations on the mobility and handling the same effectively in the sunlight. The judicious use of two containers and disposition of the said containers so as to form air spaces and the containers provided with respective glazing provides a portable, compact, light weight, easily installable solar energy based heating / cooking device having substantially reduced thermal mass obviating the need for tracking mechanism / moving the device and separate absorber, yet effectively operable during early hours of the day when the sun's ray are slanted.

Documents:

148-MUM-2008-ABSTRACT(29-11-2013).pdf

148-mum-2008-abstract.doc

148-mum-2008-abstract.pdf

148-MUM-2008-CLAIMS(AMENDED)-(29-11-2013).pdf

148-mum-2008-claims.doc

148-mum-2008-claims.pdf

148-MUM-2008-CORRESPONDENCE(19-7-2012).pdf

148-mum-2008-description (complete).pdf

148-MUM-2008-DRAWING(29-11-2013).pdf

148-mum-2008-drawings.pdf

148-mum-2008-form-1.pdf

148-mum-2008-form-18.pdf

148-mum-2008-form-2.doc

148-mum-2008-form-2.pdf

148-mum-2008-form-3.pdf

148-mum-2008-form-5.pdf

148-mum-2008-form-9.pdf

148-MUM-2008-REPLY TO HEARING(29-11-2013).pdf


Patent Number 258122
Indian Patent Application Number 148/MUM/2008
PG Journal Number 49/2013
Publication Date 06-Dec-2013
Grant Date 05-Dec-2013
Date of Filing 22-Jan-2008
Name of Patentee GADKARI AMIT S
Applicant Address RL 66 MILAP NAGAR, MIDC, DOMBIVLI-421203,
Inventors:
# Inventor's Name Inventor's Address
1 GADKARI AMIT S RL 66 MILAP NAGAR, MIDC, DOMBIVLI-421203.
PCT International Classification Number F24J2/02
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA