FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
PROVISIONAL/COMPLETE SPECIFICATION
(See section 10 and rule13J
1. TITLE OF THE INVENTION
Optically Concentrated Solar Fluid Heater
2. APPLICANT (S)
(a) NAME: Vinod Kumar
(b)NATIONALITY: Indian
(c)ADDRESS: C.Rly Colony Ajni, Nagpur RB-III/427B, PIN-440003
(India)
3. PREAMBLE TO THE DESCRIPTION Complete description enclosed
PROVISIONAL COMPLETE
The following specification describes the The following specification particularly describes
Invention. the invention and the manner in which it is to be
performed.
Annexed at A, (17-Pages)
4. DESCRIPTION {Description shall start from next page.)
Complete Specification Annexed at A, (17-Pages)
(Item no.-8)
5. CLAIMS (not applicable for provisional specification. Claims should start with the preamble ■—
"l/we Claim"onseparateage)
Annexed at B-(2-Pages)
6. DATE AND SIGNATURE (to be given at the end of last page of specification)
7. ABSTRACT OF THE INVENTION (to be given along with complete specification on separate page)

Annexed at C(1-Page)
Note.- -
'Repeat boxes In case or more than one entry.
' 'To be signed by th» applicant(s) or by authorized registered patent agent
, 'Name of the applicant should be given In full, family name In the beginning .
| *Con .plete address of the applicant should be given stating the postal index no./code, state and
I country.
'StriHe out the column which Is/are not applicable J

Complete specification
1) Title of invention:
OPTICALLY CONCENTRATED SOLAR FLUID HEATER
2) Field of invention:
This invention generally relates to the solar energy conversion and specifically to optically concentrating (with the help of convex lenses) the low grade solar energy into high grade thermal energy for heating of fluids (preferably liquids).
3) Background of invention with regard to the drawback associated with
known art: Abundant solar energy is available in sun shine period. But being low grade energy, its utilization is limited. Solar energy collectors are used widely to collect this energy and transfer it to the medium for further use.
Conventional solar heat collectors are either a flat pJate or concentrated type. In flat plate collector the aperture area and absorbing surface area are equal; hence the concentration factor is unity. Sometimes additional reflecting surfaces are utilized to enhance the quantity of beam radiation. But, all the heat energy absorbed cannot be utilized and losses of substantial portion of this energy incurred through all three modes of heat transfer viz. conduction, convection and radiation due to inefficiencies. In addition to above the quantity of these losses is also proportional to the exposed surface area. So, in one hand we have to increase the absorbing surface area to increase the quantity of heat absorbed, but in another hand it will also leads to losses of valuable absorbed heat.
Moreover, the time required to achieve the desired level of output by this system is much longer and the delivery temperature of the system is comparatively low due to absence of concentrating or reflective surfaces.

Solar concentrators - Flat absorber with flat reflectors, parabolic concentrator, compound parabolic concentrator, Fresnel lens, cylindrical parabolic concentrators are the different types of solar concentrators used for solar heating. Immense heat can be generated at localized area with the help of solar concentrator. Temperature range of 3000 °C can be achieved by this type of apparatus.
In prior art solar energy concentrators the substantial portion of heat absorbed by the absorbing surface is lost to the ambient, through heat transfer modes viz. conduction, convection and radiation due to high temperature gradient and limitations of insulations in exposed absorbing surface area.
Prior art also utilized the solar concentrators, but vast scope is still available to restrict the heat leakages from the system. Some of the limitations pertains to existing concentrators are as under -
• In case of flat absorber with flat reflectors the concentration factor is more than unity, but final heat absorbing surface area is also has substantial exposure for heat losses.
• Jn case of parabolic, compound parabolic and cylindrical parabolic concentrators, reflectors are the important component and have great contributions towards efficient working of the system. Generally glazed coatings or surfaces of reflectors get degraded shortly and performance of system deteriorated substantially. As well as frequent cleaning of reflectors are required due to adverse working environmental impacts.
• In case of Fresnel lens concentrators, the Fresnel lens may be installed with either the grooves facing the sun, the ineffective facts of the grooves are, it prevent a part of the input light from being transmitted to the focus (According to Snell's law the refracted light is deviated away from the normal on moving from a denser to a rarer medium). Also dust and water get accumulated in these groves resulting in a reduced level of performance. In the second case, the concentrator has a high surface reflection loss and large off-axis aberrations. While reflection loss causes low efficiency, the aberrations result in a low concentration ratio.
The present invention is capable to overcome the aforesaid limitations.

4) Object of invention:
A solar concentrator is required which can convert the abundant low grade solar energy into high grade energy by concentrating the beam radiation at small area, so that entire tube surfaces can be covered, except at heat absorbing points, with high quality insulation to protect heat transfer losses. Tubes are arranged in such a manner that natural convection through thermo siphoning phenomenon to circulating fluid can be established, with adequate tube length to facilitate effective residing period for the fluid. As weli as the solar concentrator is equipped with suitable solar tracking system, so that the solar radiation should always be normal to the lenses for concentration of maximum solar radiations at absorbing surface.

5) Statement of invention:
An Optically Concentrated Solar Fluid Heater comprises: a well insulated tubing system which are arranged in spiral volute form to facilitate natural convection as well as to accommodate maximum number of convex lenses and enhanced residing period for circulating fluid. Array of convex lenses are mounted on the tube in such a manner that, solar beam radiation got concentrated at focus point which is placed on openings of insulations, for heat absorbing surfaces. This immense heat absorbed at heating points is effectively augmented through suitable fins and ultimately transferred to the circulating fluid.
The present invention is also equipped with suitable solar tracking system, so that the solar radiation should always be normal to the lenses for concentration of maximum solar radiations at absorbing surface.
The salient features of the present invention is as under -
• The optical solar concentrator formed by array of convex lenses increases the intensity, by concentrating the energy available over a large surface onto a smaller surface i.e. absorbing surface.
• The aforesaid limitations attributed with the other type of solar concentrators including Fresnel lens type are not present in the present invention.
• Due to the concentration on a small area, rest of the portion of the tubes can be insulated properly; hence the heat loss is reduced. Further the thermal mass is much smaller than that of a flat plate collector and hence transient effects are small.
• The delivery temperatures being high, a thermodynamic match between the temperature level and the task occurs. As well as fluid at delivery point of this invention, can also be utilized for closed system with the help of heat exchanging devices.
• The ratio of Heat absorbed to Weight is substantially high, along with reduced floor area occupancy.

• It also helps, in reducing the cost by replacing expensive large reflectors and panels, by a less expensive optical concentration system.
6) A summary of invention:
An Optically Concentrated Solar Fluid Heater (OCSFH) comprises: Two forms of tube design can be adopted -
In first form entire fluid carrying tube is manufactured by a material, having high thermal conductivity and diffusivity e.g. copper, aluminum or material having similar configurations and insulation is provided properly, with openings to receive concentrated heat, by the outside surface of fluid carrying tube.
In another form the entire fluid carrying tube is manufactured by a material having very poor thermal conductivity and diffusivity e.g. plastics, PVC or materials having similar configurations, and specially designed internal fins are made of material having high thermal conductivity and diffusivity. These fins are inserted laterally on the circumference of the tubes, in such a manner that its one projected end can absorb the optically concentrated heat efficiently, and transfer the same to the fluid through its length, which is immersed inside the fluid.
Each convex lens is fitted in a specially designed frame and fastened with the tube at a predetermined height in a manner that, proper concentration of solar beam radiation falls on predetermined heat absorbing points. Due care should be taken while fastening the lenses, that way of solar beam radiation should be clear for each lens, and direct beam radiation should fall on normal direction of the lens surface.
Circulating fluid is entered from comparatively low height with specific pressure head and the fluid absorbs the heat from hot surfaces while coming into contact. As soon as the fluid proceeds, number of lenses in each tier gets increased due to spiral formation hence quantity of heat transferred to fluid also gets increased. This hot fluid due to some entry pressure and thermo siphoning effect proceeds towards delivery end.

It may also be possible to fabricate the tubes other than spiral volute form with or without pump, but in all such cases well concentrated heat should be collected by a highly conductive material configurations and it should be transferred to circulating fluid.
In the present invention, the said concentrator panel is interlocked to solar tracking system with the help of suitable power transmission configuration e.g. gear train, belt pulley arrangements to ensure its predetermined motion w.r.t. position of sun.
To assist with understanding the invention, reference will now be made to the accompanying drawings, which show one example of the invention.

7) A brief description of the accompanying drawing:
• Figure - 1 is the top view of single convex lens framed unit, fitted above a predetermined height from the concentrated heat absorbing point, and also showing the cross section of fluid carrying tube. It is one example of possible design according to the invention.
• Figure - 2 is the front view of figure - 1 showing cross section of said tube and suitable clamping arrangement. It is also one example of possible design according to the invention.
• Figure - 3 is the top view of the invention showing general arrangement of tube layout, mounting of non return valves, mounting of array of lenses, primary axis of rotation of said concentrator panel, solar tracking linkages like prominent components keeping in view of clarity to display. It is also one example of possible design according to the invention.
• Figure - 4 is the front view of figure - 3 also showing the arrangement to adjust the inclination of primary axis, in such a manner that solar altitude angle measured with primary axis is a right angle, mounting of array of lenses (only 3 units are shown in the fig.), stand, platform like prominent components keeping in view of clarity to display. It is also one example of possible design according to the invention.

8) Detailed description of the invention with reference to drawing/examples
Referring to Figure - 1 : which is the top view of single convex lens framed unit, fitted above a predetermined height from the concentrated heat absorbing point, and also showing the cross section of fluid carrying tube. In this drawing the convex lens 1 is fitted on the frame 5 and this frame is fastened at hinges 12. Supporting arms 2 is fitted at point 12, and other end is fitted with clamp 3, which is fastened on tube 10. This supporting frame is solving the purpose of keeping the convex lens 1 at a predetermined height from the concentrated heat absorbing surface 11, so that proper and efficient concentration of solar beam radiation can be achieved.
A fluid carrying tube 7 is shown, which either made of highly conducting material with surface heat transfer or made by insulating material equipped with fin like design for heat transfer augmentation. In present drawing a highly conductive tube is made of copper alluminium or material having similar configuration. This fluid carrying tube is covered with insulating material to restrict the losses of absorbed heat. Fluid 8 is entering and after passing through heat absorbing location 11, it gets heated up and proceeds further as comparatively warmed up fluid 9. The idea behind this is to collect the solar radiation at a large area however it is low grade energy, but when it is concentrated optically to a very small area 11 it gets converted into high grade energy flux. This flux is transferred to the fluid flowing in a confined volume.
Referring to figure - 2: which is the front view of figure - 1 showing cross section framed convex lens 1, this framed lens is hinged through supporting arms 2, these arms are clamped 3 on tube to maintain predetermined height. The tube shown in this drawing is circular in cross section; however it can also be made with tubes having any other suitable cross section. A specially designed internal fin 4 is shown in this drawing, which is provided for heat transfer augmentation. The function of this fin is to collect the concentrated heat and transfer the same to circulating fluid.

Referring to Figure - 3: is the top view of the invention showing general assembly of tube layout, mounting of array of lenses, primary axis of rotation of said concentrator panel, solar tracking linkages like prominent components keeping in view of clarity to display. In this drawing an enclosure consisting top frame 30 and bottom frame 31 is fabricated, which supports the complete concentrator pane!. Fluid carrying tube 13 is shown in spiral form which is able to accommodate maximum number of lens units, and also enhances the fluid residing period during circulation. As well as natural circulation through thermo siphoning phenomenon is possible in this configuration.
Non return valves 34 and 35 are provided at inlet and outlet respectively to ensure unidirectional flow of fluid. These valves also restrict the flow of fluid in reverse direction i.e. from delivery side to entry side in case of excessive pressure built-up.
Sensor(s) 27 is placed at a place from where appropriate quantity and quality of solar light can be received to control the solar tracking system. Spirit levels 28 & 29 in perpendicular directions and compass 33 are provided for confirming the leveling and orientation respectively in case said invention is required to be shifted at other locations.
Solar tracking control units 32 is provided which receives feedback signal from sensor(s) 27 e.g. light dependent resistor, and operate the motor with a predetermined angle of revolution. This revolution is transmitted to the linkages interlocked with said concentrator panel, to control its orientation in a manner that solar beam radiations are always in normal direction.

passes through the array of said heating points duly absorbing the heat concentrated by said array of convex lens units 26. A motor 21 for example stepper motor is controlled and operated by solar tracking control unit at predetermined angular revolution. A pinion 22 is mounted on the shaft of the said motor, this pinion is meshed with a gear 23 with a predetermined gear ratio, and this gear is linked with the said concentrator panel, so that sensor transmits feedback signal to solar tracking control unit and this unit operate the said motor. The complete solar tracking system is based on a close circuit feedback system for efficient and correct orientation of the said concentrator panel.
The supporting hollow shaft 16 is provided at inlet and delivery sides, which can rotate freely inside the spherical bearings 24, and also allow accommodate the inlet and delivery tubes. The function of this arrangement is to support the said concentrator panel and allow the fluid flow without disturbing its balancing, as well as to ensure the smooth rotation of the panel during tracking operation.
Supporting stands 19 are provided to hold the weight of entire pane! assembly supported at spherical bearings. An adjustable nut 18 and screw 17 is provided for adjusting the inclination of said primary axis perpendicular to the solar altitude angle. The function of this arrangement is to adjust the primary axis perpendicular to the solar altitude angle, which commits a little change during the year. Due to simplicity a single axis tracking system is designed in the present invention. In alternate form of design dual axis solar tracking system can be provided, which is able to track both the solar angles viz. solar altitude and solar azimuth angle, to ensure the predetermined orientation of said concentrator panel. A platform 20 is provided to support all the above components of the system.

9) Claim(s)
I claim:
1). An Optically Concentrated Solar Fluid Heater comprises: a well insulated tubing system which are arranged in spiral volute form to facilitate natural convection with enhanced residing period for circulating fluid, and arrangement also facilitating the accommodation to maximum number of said convex lens units, arrayed in such a manner that said recipient normal solar beam radiations get concentrated, which results into generation of immense heat at their respective focus points, so that heat absorbing surfaces or bodies placed at these focus points are able to absorb the heat for further transfer to the circulating fluid.
2). The receiver of claim 1, wherein said concentrating unit having its optical configuration similar to convex Sens; utilized for conversion of recipient low grade energy on large area into high grade thermal energy, at small focus area at said heat absorbing surfaces after concentration.
3). The receiver of claim 1, wherein the orientation of said concentrating panel controlled by suitable solar tracking system by rotating about its predetermined axis, so as to ensure the position of solar beam radiation be normal to the said concentrating panel.
4). The receiver of claim 3, wherein the said concentrator panel restore its orientation to initial position of sunrise (i.e. at first limit of predetermined solar azimuth angle), after completing its regular turning about said axis upto sunset {i.e. at last limit of predetermined solar azimuth angle).
5), The receiver of claim 1, wherein the fluid is entered through one end of spiral volute tube arrangement, with specific inlet pressure at lower height and discharge the output at a higher datum with specific pressure and gain in heat content, duly ensuring the unidirectional flow of fluid with provision of suitable non return valves at inlet and outlet sides.

6). The receiver of claim 2, wherein the inlet fluid is absorbing heat after passing through each heat absorbing points, which are either the surface of highly conductive tubes or projection of specially designed internal fins for augmentation of heat transfer to fluid.
7). The receiver of claim 1, wherein in first form entire fluid carrying tube is manufactured by a material having high thermal conductivity and diffusivity e.g. copper, aluminum or material having similar configurations, and insulation is provided properly with openings to receive concentrated heat by the outside surface of fluid carrying tube. In another form the entire fluid carrying tube is manufactured by a material having very poor thermal conductivity and diffusivity e.g. plastics, PVC or materials having similar configurations, and specially designed internal fins are made with projection located at said heat absorbing points of material having high thermal conductivity and diffusivity.
8). The receiver of claim 1, wherein convex iens unit while mounting at different radius of spiral volute tube should not obstruct the way of solar beam radiation of other lens units, means to say that each lens should always be able to receive uninterrupted solar beam radiation during sun shine period on its full recipient area.
9). The receiver of claim 1, wherein a main enclosure or frame, to support and hold the entire tube arrangements, and also facilitate its integrated and uniform rotation of said concentrator panel.
10). An Optically Concentrated Solar Fluid (preferably liquid) Heater substantially as herein described and illustrated in the figures of the accompanying drawings.