FIELD OF INVENTION
The present invention relates to an improved automatically re-orientable solar thermal sun tracker for introducing a wake up system for tracking the sun from sunrise to sunset to increase power output. More particularly the invention relates to an early wake up system for solar passive tracker for array of solar photovoltaic panels. The invention discloses an early wake system for solar passive tracker utilizing electric heat for pressurizing the liquid and transferring from one container to the other and tilting the passive tracker towards the East in the late evening or early morning so that the tracker is ready to receive the solar energy from 6 AM and deliver enhanced energy output. Thereafter, the thermal radiation from the Sun is utilized for tilting the tracker towards the Sun during the day.
BACKGROUND OF THE INVENTION
Solar Thermal Sun Tracker is disclosed in Indian Patent application nos, 818/KOL/2010, 177/KOL/2015, 201731010190, and Solar Passive Trackers illustrated in US Patent 4476854, 2004/0112373, 4175391, 4275712 and 4027651. Such trackers employ a pivotal frame, having at least one each canister at East end and West end which are interconnected through their lowers ends. Shadow bars / covers overlie the outer half of each canister to shade the proximal canister from direct sunlight when the

sun is not directly above the canister surface. A volatile fluid and its vapor is contained within the canisters, and as the Sun moves from East to West, the East canister gets heated and forces the volatile fluid into the West canister, thereby tilting the frame westward to follow the Sun. The frame is balanced and points directly at the Sun when equal sunlight falls on each canister.
This principle of operation is disclosed in Indian Patent Application nos. 818/KOL/2010, 177/KOL/2015 & 201731010190. The device mentioned in the patents is mounted on a single/multiple pole structure and follows the Sun from East to West and then remains oriented overnight facing the West. It reorients itself towards East facing the Sun in the next day morning after the sunrise. However, the morning wake up is delayed due to the time taken for preheating of the container and thus the energy gain due to tracking is reduced.
In 818/KOL/2010, the invention relates to a solar tracker and in particular a Sun tracker utilizing the thermal radiation from the Sun for tilting towards the Sun during the day and to reorient itself to face the Sun in the morning after the sun-rise. More particularly, the invention relates to an automatically re-orientable solar thermal Sun tracker.

US Patent No. 4275712 to Stephen C. Baer provides heat collecting surfaces which enables transfer of the liquid between the canisters, specifically in the morning to assist repositioning of the canister to face the sun.
US Patent No. 4175391 to Stephen Baer proposes an automatic night time resetting mechanism in a Sun tracker by providing at least two containers with low boiling point liquid having differential cooling rates. When the Sun sets, the air cools and the evaporated fluid in the containers condenses. By regulating the rates of cooling, the east container is cooled faster than the west container which causes transfer of fluid from the west container because of higher pressure of the vaporized liquid in the west container. The transfer of the fluid to the east container makes it heavier and tilt the array to the East to await rising of the Sun.
The Gas Spring Solar Tracker disclosed in US Patent No. 4476854 relates to a solar tracker and in particular a solar tracker utilizing a gas spring to reorient the tracker when sunlight is not available.
US Patent 2004/0112373 A1 by Derek Djeu, on Passive Solar Tracker for a solar concentrator represents one approach to a passive solar tracking system capable of focusing solar radiation onto a small target at all times of the year. The device consists of a two-axis gimbal system with its orientation controlled by interconnected ballasts

filled with a volatile fluid. Accurate focusing realized by ensuring that each significant mass element is balanced by another element of equal mass equidistant from and diametrically opposite to it through the point of intersection of the two gimbal axes for all possible orientations of the system.
The Solar Energy Powered Sun Tracker described by Roland W Robbins in the US Patent 4027651 relates to an apparatus for causing a solar energy collector to constantly follow the sun. The invention utilizes the sun's radiant energy reflected from a mirror device, which differentially heat a plurality of fluid-containing reservoirs resulting generation of a differential pressure to rotate the apparatus and the collector.
The principal advantage of the Solar Trackers known in the art is their ability to track the Sun in a totally passive fashion during the day and reorient itself towards the East in the evening or early morning before the sunrise. The principle advantage of the current invention is to reorient the tracker towards East before the sunrise next day morning. This is achieved by controlled electrical heating for a specific duration of the container on the West side simulating the heat generated by solar energy. The early wake up system enhances the energy generated by the prior art solar thermal sun tracker by 7-8 %.

OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose an improved automatically re-orientable solar thermal sun tracker for introducing a wake up system for tracking the sun from sunrise to sunset to increase power output, which is capable of eliminating disadvantages of prior Art.
Another object of the invention is to propose an improved automatically re-orientable solar thermal sun tracker for introducing a wake up system for tracking the sun from sunrise to sunset to increase power output, which is capable of receiving sun rays perpendicular to the surface.
A still another object of the invention is to propose an improved automatically re-orientable solar thermal sun tracker for introducing a wake up system for tracking the sun from sunrise to sunset to increase power output, which is able to control the angle of rotation of tilting frame having plurality of photovoltaic (PV) modules.
A further object of the invention is to propose an improved automatically re-orientable solar thermal sun tracker for introducing a wake up system for tracking the sun from sunrise to sunset to increase power output, which can dampen the noise and vibration generated due to sudden high winds.

A still further object of the invention is to propose an improved automatically re-orientable solar thermal sun tracker for introducing a wake up system for tracking the sun from sunrise to sunset to increase power output, which is capable of reorienting in the early morning or late evening.
A still another object of the invention is to propose an improved automatically re-orientable solar thermal sun tracker for introducing a wake up system for tracking the sun from sunrise to sunset to increase power output, which is simple, cost effective, maintenance free and reliable.
SUMMARY OF THE INVENTION
Accordingly, there is provided an automatically re-orientable modular type solar thermal Sun tracker for photovoltaic arrays for deploying in the MW capacity, stand-alone distributed solar power systems and solar water pumping systems comprising:
a support device consisting of a panel fixing frame attaching a plurality of photovoltaic (PV) modules; front and rear pole members with base plates affixed at the lower end; the upper end of the front and rear pole members having Plummer block bearings affixed, through which said panel fixing frame is connected to the pole members; at the top end pole members, a stopper is fixed to limit the angle of rotation of the panel fixing frame on East and West side; the stoppers are provided with

vibration dampeners to dampen the vibration and noise when the tracker hits the stopper due to sudden high winds; the bottom portion of the pole members accommodating the base plate rigidly fixed to a concrete base; at least two containers containing volatile fluid located at the extreme ends of the panel fixing frame which rotates along East to West direction with the axis of rotation oriented North - South; the containers flowably connected to each other via an inter-connecting tube for fluid-transfer; a plurality of shadow casting covers provided to the containers such that depending on the position of the sun, the covers allow the respective container distal to the sun rays to receive higher impingement causing temperature differential of the volatile liquid in two containers which leads to inter-transfer of the liquid between the containers including application of gravitational force in the containers leading the tracker to automatically tilt from West to East direction in the morning after the sunrise, and East to West direction during the day time; the tracker remains facing the West direction after the Sun set.
The present invention thus provides a device to reorient itself towards the East in the evening or early morning before the sunrise. This is achieved by controlled electrical heating for a specific duration of the container on the West side simulating the heat generated by solar energy. The early wake up system enhances the energy generated by the prior art solar thermal sun tracker by 7-8 %.

The tracker is provided with at least two containers which can withstand the pressure of the volatile fluid. The shape of the container can be of any geometry (cross section) for example - circular, square, rectangular, or any other irregular shape. The containers are placed at the extreme ends of the tracker frame for deriving maximum gravitational force due to differential quantity of liquid disposed in the containers. The containers are coated with black paint to absorb maximum energy incident on the surface and also to radiate maximum heat energy from the surface when under shadow.
The containers are pressure and vacuum tested before filling with the working fluid so that there is no leakage, and enabled to provide a reliable and maintenance-free operation.
The surface of the trackers frame is almost fully covered with a plurality of array of PV panels so that a maximum number of panels can be accommodated; at the same time a gap is provided between the adjacent panels to allow the flow of air and reduce the wind forces.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows front view of the panel fixing frame, PV panels, liquid containers.
Figure 2 shows a side view of the Modified Solar Thermal Sun Tracker including the

details of the PV array, supporting structure, front and rear pole structure according to the invention.
Figure 3 shows a top view of the modified solar thermal sun tracker of the
invention showing the details of PV panels mounted on the tracker, containers shadow covers, shock absorber, vibration damper, early wake up heater and inter-connecting tube.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
In figure 1, 2 and 3 a preferred embodiment of the solar thermal Sun Tracker according to the present invention is illustrated which consists of a structure supporting an assembly of front pole (1), rear pole (2), structure members, a plurality of Photovoltaic panels (3) at least two liquid containers (4), a proximal container, another distal container, an interconnecting tube (5), at least two shadow covers (6), a plurality of shock absorbers (7), and vibration dampeners (8), Plummer block and bearings (9), early wake up heater (10), panel fixing frame (11) and a working fluid.
The supporting structure consists of a panel fixing frame (11) where the PV panels (3) are mounted using a set of nuts and bolts. The Plummer block bearings (9)

are fixed on the top end of the supporting pole assembly (1 & 2). The panel fixing frame (11) is mounted on the supporting pole members (1 & 2) through the Plummer block bearings (9). At the top end of the of the pole assembly (1 & 2), vibration dampens (8) are fixed to limit the movement angle of the panel fixing frame (11) on East and West side. The bottom end of the pole assembly (1 & 2) base plate is fixed to the concrete foundations in the ground.
The containers (4) preferably of circular cross section of desired diameter, to accommodate required quantity of working fluid, are fabricated. The containers (4) are fitted to the panel fixing frame (11) through a set of brackets / clamps. The Shadow covers (6) are fixed to the containers (4) by a set of brackets / clamps and bolts. The inter-connecting tube (5) is also connected to the containers (4) by threaded joints.
The assembly of the containers (4) and inter-connecting tube (5) is pressure tested and leakages if any are sealed. The containers (4) are vacuum tested and charged with required quantity of volatile liquid. The containers (4) are painted black to absorb maximum solar radiation and also to radiate maximum energy when it is under shadow.
The containers (4) are fixed to the panel fixing frame (11) as shown in the figure 3 by the set of brackets/clamps and bolts. The containers (4) are charged with a

volatile working fluid, and sealed. The volatile fluid used is to tilt the tracker due to gravitaitional force applied by transfer of fluid from one canister to other canister. The shadow covers (6) are fixed to the containers (4) with set of the nuts and bolts. The shadow covers (6) cast shadow on half of the container (4) surfaces when the tracker is facing the Sun. Under this condition, both the containers (4) are equally heated and the pressure inside the containers (4) is substantially equal. The shock absorber (7) is selected depending on the capacity of the array of PV panels (2) installed on the trackers, and fitted to the tracker connecting the panel fixing frame (11) and a bracket extended from the supporting pole assembly (1 & 2) by means of a set of bolts and nuts. The panel fixing frame (11) along with the PV panels (3) rotate about the axis through the Plummer block bearings (9). The shock absorber (7) resist movement of the tracker i.e. panel fixing frame (11) along with the PV panels (3) due to sudden winds or any other reasons. The shock absorber (7) also allow very slow motion of the tracker due to the gravitational force because of the differential liquid held in the containers (4). At the top end of the pole assembly (1 & 2), a vibration dampener is fixed to limit the angle of rotation of the panel fixing frame (11) on East and West side.
The inventive Solar Thermal Sun Tracker is positioned in such a way that the axis of rotation is oriented towards North and South direction, so that the tracker can rotate East and West direction respectively. Once the tracker is positioned, depending on the

location of the Sun, the proximal container (4) gets more shadow in comparison to the distal container (4). This results in higher heating of the distal container and thereby increasing the liquid pressure inside it due to additional vaporization. The increase in the pressure inside the distal container pushes some liquid to the proximal container depending on the pressure difference. Thus the proximal container becomes heavier and rotates the tracker towards the Sun till the shadow by the cover (6) on both the containers (4) is identical. As the Sun moves from East to West direction, the tracker follows the sun till the evening. The tracker remains facing West during the evening and the next day morning. When the Sun rises in the East, the Sun rays directly fall on the west side container (4). This operation enables heating of the west side container and thereby pressurizing the container (4) because of the vapors generated by the working fluid. The pressure difference between the containers (4) pushes the liquid from west side container (4) to the east side container (4) through the interconnecting tube (5).

WE CLAIM
1. An improved automatically re-orientable solar thermal sun tracker for introducing a wake up system for tracking the sun from sunrise to sunset to increase power output, comprising;
a structure comprising an assembly of front pole (1), rear pole (2);
a panel fixing frame (11) disposed for accommodating PV panels (3);
a plumber block bearings (9) fixed on top ends of the supporting pole assembly (1, 2);
at least two liquid containers (4) with an interconnecting tube (5) connecting the said containers (4);
at least two shadow covers (6) for blocking the sun to create shadow on the containers when required;
a plurality of shock absorbers (7) and vibration dampeners (8) for dampening the vibration and noise;
a stopper disposed for limiting angle of rotation of panel fixing frame (11);
a plurality of Plummer block bearings (9) fixed on the top end of the supporting pole members (1,2);

Characterized in that;
an early wake up heater (10) disposed in the western side liquid container and connected to an electric source through a timer so that an early wake up system configured for rotating the tracker towards east side in evening or early morning making the tracker to wake up and face the sun from 6 AM resulting an improvement of the total energy gain from the tracker during the day by upto 7-8%.
2. The improved sun tracker as claimed in claim 1, wherein the tracker is provided with an early wakeup heater to western side liquid containers for rotating tracker towards East side in evening and early morning, due to which tracker would be facing the sun from 6 AM in morning and is able to generate 7 to 8% excess energy in comparison to the prior art solar thermal sun tracker without this early wake up system.
3. The improved sun tracker as claimed in claim 1, wherein the trackers (T) mounted on pole support members is enabled to withstand high winds.
4. The improved sun tracker as claimed in claim 1, wherein the SPV arrays are provided with vibration dampers (8) at the top end of the pole members (1, 2), to limit the movement angle of the panel fixing frame (11) on East and West side.

5. The improved sun tracker as claimed in claim 1, wherein the stoppers are provided with vibration dampers to dampen the vibrations and noise in case the tracker hits the stopper due to sudden high winds.
6. The improved sun tracker as claimed in claim 1, wherein the covers are bent in an angle to provide a shade on half portion of the containers (4) when it is facing the sun and allow a reflection of the sun rays to heat the containers (4).
7. The improved sun tracker as claimed in claim 1, wherein shock absorber (7) are disposed to absorb shock loads due to wind or other environment hazards and allow slow movement of the tracker during the tracking for improving the tracking accuracy and enabling re-orientation of the tracker to the original position after a change in position due to disturbing force generated by abnormal wind flow.
8. The improved sun tracker as claimed in claim 1, wherein it is configured to be modular type for mounting array of SPV panels of capacity from 1 to 5 kW peak.
9. The improved sun tracker as claimed in claim 1, wherein the trackers are enabled to generate more than 15% energy compared to the array of SPV panels mounted on fixed tilt structures.

10. The improved sun tracker as claimed in claim 1, wherein the panel fixing frame (11) along with PV panels (3) rotates about the axis through the Plummer block bearings (9).