FORM 2
THE PATENTS ACT. 1970
(39 of 1970)
&
The Patents Rules 2003
PROVISIONAL/ COMPLETE SPECIFICATION ( See section 10 and rule 13 )

1. Title of the Invention :

SOLAR COOKER

2. Applicant(s)
Name, Nationality address:

NATIONAL INSTITUTE OF DESIGN, Paldi Ahmedabad 380007, India Indian Institute.

3. Preamble to the description :
:
1 0 NOV 2008
COMPLETE : The following specification particularly describes the invention and the manner in which it is to be performed.


FIELD OF THE INVENTION:
This invention relates to a solar cooker.
This invention further relates to a box type solar cooker, under the broad category of flat-plate collector type solar cooker.
BACKROUND OF THE INVENTION:
It is impossible to replenish non-renewable sources of energy. The quantity of such resources at our disposal is constantly on the decline. These resources also run the risk of being tremendously expensive and detrimental to the environment. Crude oil, natural gas and petroleum have been the backbone of some of the world's most powerful economies and it is essential to conserve these resources.
In rural India, more than 80% of quantum of energy is utilized for the purpose of cooking. Traditional fuels like firewood, animal dung and crop residue emit smoke, pollute the atmosphere and are deleterious to the health and safety of family members, particularly women. It has been observed that switching over to solar energy for cooking is an economically viable option for the rural population.
2

The California-based Solar Cookers International had rated India as the best country in the word in terms of solar cooking potential. Unlike Scandinavian countries and a few other countries which are close to the North Pole, India's geographical location has been very favourable in making the optimum use of solar energy. Most of the locations in India have more than 275 days of bright sunlight in a year. A significant portion of the cooking energy requirement is at low temperatures. Solar cookers are ideal for meeting such thermal energy requirements.
Box type solar cookers, owing to their ease in operation and simple construction have been very popular in India. The flat absorber plate convert's the sun's radiation into heat within the box. The space in the cooker is enough to accommodate three to four vessels simultaneously. Box type solar cookers of various designs are available in the market. The Bureau of Indian Standards has given the basic specification for these types of cookers (IS 13420:2000).
However, most of the cookers existing in the art, are not efficient enough to complete the cooking process within the appointed time. Furthermore, their efficiency starts declining as the sunlight diminishes, particularly from afternoon, and by evening they stop functioning altogether.
3

OBJECTS OF THE INVENTION:
It is therefore an object of this invention to propose a solar cooker, which is efficient and fast.
It is a further object of this invention to propose a solar cooker, which can remain operational in reduced light.
Another object of the invention is to propose a solar cooker, which is simple and cost-effective.
These and other objects and advantages of the invention will be apparent from the ensuing description, when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Fig 1 shows a sectional view of the solar cooker. Fig 2 shows a plan view of the solar cooker.
4

Fig 3 shows an elevation view of the solar cooker. Fig 4 shows a side view of the solar cooker. DESCRIPTION OF THE INVENTION:
According to this invention is provided a solar cooker.
This newly invented solar cooker is of the box-type having flate plate collectors. The flat absorber plate converts the sun's radiation into heat within the box. The sectional view (Fig 1) of the cooker shows an insulated box (1) with an absorber tray (2) affixed therein. The box is adapted to hold a plurality of cooking vessels, preferably four in number. The box also consists of a lid (4) and reflector (5) which is stationed over the lid, and fixed to the walls of the box by conventional means such as hinges and brackets. The absorber tray covers the base (6) of the box and extends upwards along the rear inner wall (7) of the box. The cooking vessels (3) are blackened for maximum absorption of heat and placed inside the box, as shown in the plan view (Fig 2).
5

The elevation view (Fig 3) shows the solar cooker with the reflector (5) kept open. The lid (4) is transparent and double layered, having an outer wall (8) and an inner wall (9). The lid is rounded at the front and it extends downwards, over the inclined side walls and is affixed by means of clasp arrangements over the front rim (10) of the box as shown in the right hand side view (Fig 4) of the cooker.
The reflector focuses the sun rays falling on it, on the absorber area comprising the cooking tray and the vessels. The blackened surface of the cooking vessels and the absorber tray together, take in the heat, which is then transferred to the food placed inside the vessels; thereby facilitating the cooking process.
As shown in the elevation view, the front wall of the newly designed box type solar cooker and a part of its walls on either sides (11) has been removed and covered by a double layered transparent lid. This helps the inclined solar rays to pass through the lid in the morning and evening hours.
The cooking process, through the means of the box type solar cooker takes 1.5 to 2.5 hours. Measures are being taken to capture the inclined
6

sun rays and reduce the shadow effect within the cooker. This would help prepare the meal by 11:00 a.m. Thus the solar cooker can remain operational till late in the evening. The innovatively designed box type solar cooker will be devoid of front walls. This will ensure that the inclined solar rays are captured inside, thereby reducing the shadow effect.
The elimination of the front wall and part of the side walls of the cooker results in the increased surface area of the double layered transparent lid. The shadow effect will be considerably reduced and this will ensure that maximum amount of sunlight gets converted into heat energy.
The overall efficiency of the cooker is greatly enhanced as it can ensure that food is prepared at the appointed time. Further, it is an inexpensive product, so that most of the rural population can afford it, It has a simple mode of functioning and is not cumbersome to handle.
The women in both rural and urban areas can be the greatest beneficiaries of this user-friendly solar cooker. Since it is not at all expensive, the rural population can easily afford it. The box type solar cooker has neither a complex way of functioning, nor is it cumbersome to
-7-

handle. It is definitely a product that will make the user's adjustment to daily life more comfortable.
8

WE CLAIM:
1. A solar cooker comprising
an insulated box (1),
an absorber tray (2),
cooking pots (3),
double layered transparent lid (4) and a reflector (5), the box
having inclined side walls (11) and no front wall.
2. The solar cooker as claimed in claim 1, wherein the absorber tray (2) is disposed on the inner base and extends upwards along the rear wall of the box.
3. The solar cooker as claimed in claim 1, wherein the cooking pots (3) are blackened and placed on the absorber tray (2).
4. The solar cooker as claimed in claim 1, wherein the lid (4) is transparent and double walled, being provided with an outer wall (8) and an inner wall (9).
9

5. The solar cooker as claimed in claim 1, wherein the front edge of the lid (4) extends downwards to meet the front rim (10) of the box.
6. The solar cooker as claimed in claim 1, wherein the side walls (11) of the box (1) are inclined at an angle.

(I. BANERJEE)
of L S DAVAR & CO.,
Applicants Agent.
Dated this 6th day of NOVEMBER 2008
10