WO2003010471A1

WO2003010471A1 - Solar tracking system and apparatus for warming water using thereof

Info

Publication number: WO2003010471A1
Application number: PCT/KR2002/001397
Authority: WO
Inventors: Jong Geun Park
Original assignee: Jong Geun Park
Priority date: 2001-07-25
Filing date: 2002-07-25
Publication date: 2003-02-06
Also published as: KR100420839B1; KR20010079476A

Abstract

Disclosed are a solar tracking apparatus and a water heating apparatus using the solar tracking apparatus, which are capable of tracking the solar along its orbit, which are made at low cost to be commercially sold, and which increase its efficiency of 30∩60 % when to be adopted to a water heating apparatus using the solar heat, a solar furnace and a generator using the solar heat, in which a light receiving section is formed to receive the solar light in an optic condition as the orbit of the solar is divided into a plurality of sections, and which includes a sensor part for tracking the orbit of the solar by sensing a temperature of the solar heat collected in the respective light receiving part while driving a motor to rotate a place for collection the solar heat along the orbit of the solar, and a rotation sensing sensor for stopping the rotation of the plate for collecting the solar light when the plate reaches at a position of receiving the solar light in the optic condition.

Description

SOLAR TRACKING SYSTEM AND APPARATUS FOR WARMING WATER USING

THEREOF

TECHNICAL FIELD The present invention relates to a solar tracking system and a water heating apparatus using the solar tracking apparatus, and more particularly to a solar tracking apparatus and a water heating apparatus using the solar tracking apparatus, which are capable of heating water at high temperature, which have a simple structure so as to be made and sold at low cost, and which are adapted to a water heater, a solar furnace and a generator using solar heat to increase an efficiency of the water heater using solar energy, the solar furnace, and the generator using the solar heat by maximizing an accuracy and a heat collection efficiency of the solar tracking apparatus.

BACKGROUND ART

Presently, human being faces to two problems that should be solved. The first problem is a running dry of fossil energy such as petroleum and coal and the second problem is whether the climate variation agreement can be implemented in order to prevent temperature of the earth from increasing resulting from that the use of the fossil energy increases. The fossil energy, which the human being thinks that it can be used forever, must be disappeared in 210 years if a present amount of the fossil energy is continuously used. That is, the petroleum can be used for 40 years, the coal used for 210 years, natural gas used for 65 years, and uranium disappeared in 50 years. In order to solve the present problems, alternative energy, so called future energy or green energy, has been developed. Every country has greatly invested to develop and feed the alternative energy.

The alternative energy includes solar light, solar heat, biomass, wind force, the heat of the earth, fuel cell, hydrogen energy, and energy obtained from waste. In relation to the present invention, the applicant has attended to the solar light and the solar heat. The solar has a temperature of 6,000°C at a surface thereof, and a temperature of 15,000,000°C at the center thereof so as to emit a great amount of heat and light equal to the total amount of the energy of 9.2 x 1022 kcal. However, since the earth is at a distance of about 15 ten million km far way from the solar, the amount of solar radiation energy, which approaches the earth, is about 2cal.

The solar radiation energy is a source of energy necessary to a life of the human being as well as a source of ocean current or various weather conditions. There are such different examples using the solar energy as solar cell, a water heating apparatus, a solar house, a solar furnace, and a generator using the solar energy.

In a system using the solar energy, such as the water heating apparatus, the solar house, the solar furnace and the generator, very important thing to increase energy efficiency is that the system can absorb the solar energy for a long time, while an apparatus for collecting the solar heat must have a high efficiency. That is, as the solar moves along its orbit from sunrise to sunset, the apparatus for using the solar heat cannot receive the solar heat in an optic condition if the apparatus is fixed, resulting in degrading the efficiency of the system.

It is known to an academic world that if the apparatus for collecting the solar heat tracks the orbit of the solar, the apparatus for collecting the solar heat can absorb the solar heat in the optic condition to increase the efficiency of the system up to 30~60%. Further, many people has proposed the solar tracking apparatus.

The Korean Laid-Open Patent Publication No. 1983-2206 (published on May 23, 1983), The Korean Laid-Open Patent Publication No. 1993-978 (published on January 16, 1993), The Korean Laid-Open Patent Publication No. 97-16643 (published on April 28, 1997), and The Korean Laid-Open Patent Publication No. 2001-25541 (published on April 6, 2001) disclose a solar tracking apparatus. Since the apparatus for tracking the solar according to the publications has a structure in that a programmed microprocessor controls the apparatus to move along the orbit of the solar, however, the apparatus is complicated, of which the accuracy is lacked. As a result, the apparatus cannot be commercially used. Furthermore, the Korean Patent No. 185653 (registered on December 28, 1998), the Korean Utility Model No. 210608 (registered on November 6, 2000), the Korean Utility Model No. 194013 (registered on June 16, 2000), the Korean Laid- Open Patent Publication No. 2001-44368 (published on June 5, 2001), and the Korean Laid-Open Patent Publication No. 2001-44369 (published on June 5, 2001) have proposed the plate for collecting the solar heat and the solar light. The plate for collecting the solar heat and the solar light according to the conventional art has a complicated structure and a lacked accuracy. There are problems in that the efficiency of the plate for collecting the solar heat and the solar light decreases and it is difficult to commercially use the plate for collecting the solar heat and the solar light.

DISCLOSURE OF INVENTION Therefore, the present invention has been developed to solve the above- mentioned problems. It is an object of the present invention to provide a solar tracking apparatus which is capable of tracking the solar along its orbit, which is made at low cost to be commercially sold, and which increases its efficiency of 30~60% when to be adopted to a water heating apparatus using the solar heat, a solar furnace and a generator using the solar heat, in which a light receiving section is formed to receive the solar light in an optic condition as the orbit of the solar is divided into a plurality of sections, and which includes a sensor part for tracking the orbit of the solar by sensing a temperature of the solar heat collected in the respective light receiving part while driving a motor to rotate a plate for collecting the solar heat along the orbit of the solar, and a rotation sensing sensor for stopping the rotation of the plate for collecting the solar light when the plate reaches at a position of receiving the solar light in the optic condition.

It is the other object of the present invention to provide a water heating apparatus for maximizing a collection of solar heat, in which the solar light collecting plate is comprised of two reflecting mirrors opposite to each other, which have a convex shape and which are made from a stainless steel having a desired width and length, and in which a double-sided heat collecting plate is disposed between the mirrors to collect the heat reflected from the reflecting mirrors in order to heat the water.

BRIEF DESCRIPTION OF DRAWINGS Other features and advantages of the present invention will become more apparent from the following description taken in connection with the accompanying drawings, wherein:

FIG. 1A is a perspective view of a solar tracking apparatus according to the present invention; FIG. 1 B is a side view of the solar tracking apparatus according to the present invention;

FIG. 2A is a perspective view of a sensor part of the solar tracking apparatus according to the present invention;

FIG. 2B is a front view of the sensor part of the solar tracking apparatus shown in FIG. 2A, which illustrates a light receiving section;

FIG. 2C is a partially sectional view of the sensor part of the solar tracking apparatus shown in FIG. 2C;

FIG. 2D is a view of an electric circuit of a sensor for sensing a temperature according to the present invention, in which the sensor pertains to the sensor part of the solar tracking apparatus;

FIG. 3A is a perspective view of a sensor for sensing a rotation of a plate for tracking an orbit of the solar;

FIG. 3B shows operational states of the sensor for sensing the rotation of the plate shown in FIG. 3A; FIGS. 4A and 4B are a view of an electric circuit of the solar tracking apparatus according to the present invention;

FIG. 5 is a perspective view of a system for heating the water using the solar tracking apparatus according to the present invention;

FIG. 6 is a sectional view of a plate for collecting the solar heat according to the present invention, in which the plate is adapted to the system for heating the water using the solar tracking apparatus; FIG. 7A is a sectional view of the plate for collecting the solar heat according to the present invention, in which the plate is adapted to the system for heating the water using the solar tracking apparatus; and

FIG. 7B is an enlarged sectional view of the plate for collecting the solar heat, taken along a line C-C in FIG. 7A.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a solar tracking apparatus according to the embodiment of the present invention will be described in detail with reference to the accompanying drawings FIGS. 1 to 7B.

FIG. 1 A is a perspective view of the solar tracking apparatus according to the present invention and FIG. 1B is a side view of the solar tracking apparatus according to the present invention.

Referring to FIGS. 1A and 1B, first and second upper frames 12 and 13 are respectively installed to both ends of a lower frame 11 , which are rigidly fixed by auxiliary frames 14a and 14b to form a body 10 of which a structure can be changed according to a place and its area to install the body 10.

First installation portion 20 and second installation portion 22 are respectively formed at a side of the first upper frame 12 constructing the body 10, which are spaced at a desired distance opposite to each other. A motor 21 is disposed on an upper surface of the first installation portion 20 while a first support 26a is fixed to an upper surface of the second installation portion 22 to support a rotational shaft 25 which is provided with a fully 25a. The motor 21 is connected through a first belt 24a to a speed reducer 23 which is coupled through a second belt 24b to the fully 25a of the rotational shaft 25, resulting in that the rotational shaft 25 rotates at a constant ratio of a speed reduction when the motor is operated.

A control panel 17 containing an electric circuit is mounted on a side of the second upper frame 13 constructing the body 10 in order to control a system such as a power supply. Furthermore, a second support 26b also is installed to the side of the second upper frame 13 to support the rotational shaft 25 and to help a smooth rotation of the rotational shaft 25. A sensor part 60 is mounted on a top portion of the second upper frame 13 to divide an orbit of the solar into plural stages according to an arbitrary angle of the solar and to apply a driving signal to the motor 21 in order to rotate the rotational shaft 25 along the orbit of the solar as a contact point of the solar light and the sensor part 60 varies due to the temperature of the solar heat sensed in the divided angular section.

A solar collector 40 for collecting the solar heat is mounted along a lengthwise of the rotational shaft 25 on the center portion of the rotational shaft 25, which moves along with the rotational shaft 25 as the motor 21 rotates the rotational shaft 25.

Furthermore, a rotation sensing part 30 for sensing a rotation of the rotational shaft 25 is mounted on a side of the rotational shaft 25 to stop the operation of the motor 21 when the solar collector 40 for collecting the solar heat rotates along with the rotational shaft 25 to track the orbit of the solar in the optic condition as the sensor part 60 for tracking the orbit of the solar detects the solar light.

Here, the solar collector 40 for collecting the solar heat has a different size according to the use thereof, which is used as a solar cell to generate electric using the solar light or as a light collecting plate to obtain a high temperature of heat using the solar light.

FIG. 2A is a perspective view of the sensor part 60 for tracking the solar to drive the motor 21 in order to track the orbit of the solar, FIG. 2B is a front view of the sensor part 60 shown in FIG. 2A, and FIG. 2C is a partially sectional view of the sensor part 60 shown in FIG. 2C, in which light receiving sections according to the orbit of the solar are illustrated.

As shown in FIGS. 2A to 2C, a hemisphere fixture 67 having a desired size is formed at the center portion of a support 66, on which first, second, third, fourth, fifth and sixth partitions 61a, 61b, 61c, 61d, 61 e and 61f are installed at a desired distance from one another. Sidewalls are installed in the first to sixth partitions 61a, 61b, 61c, 61d, 61e and 61f to form first, second, third, fourth and fifth receiving parts 63a, 63b, 63c, 63d and 63e.

First, second, third, fourth and fifth lenses 62a, 62b, 62c, 62d and 62e are mounted on each upper surface of the sidewalls defining the first, second, third, fourth and fifth light receiving parts 63a, 63b, 63c, 63d and 63e to collect the solar light. First, second, third, fourth and fifth light receiving sections 65a, 65b, 65c, 65d and 65e are formed in the respective first, second, third, fourth and fifth light receiving parts 63a, 63b, 63c, 63d and 63e to absorb the solar light in the optic condition along the orbit of the solar. An external-temperature sensing sensor 68 is installed to a side of the support

66, as shown in FIG. 2C, of which a light sensing point varies according to a temperature of atmosphere when the solar heat has a low temperature in the spring, the autumn and the winter, and when the solar heat has a high temperature in the summer. First internal-temperature sensing sensors 64a-1 , 64a-2, 64a-3, 64a-4 and 64a-5 and second internal-temperature sensing sensors 64b-1 , 64b-2, 64b-3, 64b-4 and 64b-5 are contained in the second, third, fourth and fifth receiving parts 63b, 63c, 63d and 63e. The first internal-temperature sensing sensors 64a-1, 64a-2, 64a-3, 64a-4 and 64a-5 are set at a certain temperature to operate in the condition of the low temperature such as the spring, the autumn and the winter according to the contact between the external-temperature sensing sensor 68, while the second internal-temperature sensing sensors 64b-1 , 64b-2, 64b-3, 64b-4 and 64b-5 are set at a special temperature to operate in the condition of the high temperature such as the summer.

Here, the temperatures set in the external-temperature sensing sensor 68, the first and the second internal-temperature sensing sensors 64a-1 , 64a-2, 64a-3, 64a- 4, 64b-1 , 64b-2, 64b-3, and 64b-4 can be varied. A temperature switch is used in the external and internal sensors, of which contacts are connected to each other when the temperature of the solar heat collected by the second, third, fourth and fifth lenses 62b, 62c, 62d and 62e reaches the temperature set in the sensor, but no sensor is installed in the first receiving part 63a.

FIG. 2D shows an electric circuit of a sensor for sensing a temperature according to the present invention, in which the external-temperature sensing sensor 68 is connected to the first and second internal-temperature sensing sensors 64a- 1~64a-4, 64b-1~64b-4. The external-temperature sensing sensor 68 detects the temperature of the atmosphere to operate by itself according to the temperature of the solar heat in seasons such as the spring, the summer, the autumn and the winter, which comes in contact with a " " "contact when the temperature of the atmosphere is lower than the set temperature and which comes in contact with a "©"contact when the temperature of the atmosphere is higher than the set temperature.

The first internal-temperature sensing sensors 64a-1 , 64a-2, 64a-3, and 64a-4 are connected to the " " "contact of the external-temperature sensing sensor 68, of which the contact point turns off when the internal-temperatures of the second, third, fourth and fifth receiving parts 63b, 63c, 63d and 63e are lower than the set temperature and of which the "©"contact turns on when the internal-temperatures of the second, third, fourth and fifth receiving parts 63b, 63c, 63d and 63e are higher than the set temperature. The second internal-temperature sensing sensors 64b-1, 64b-2, 64b-3, and 64b-4 are connected to the "©"contact of the external- temperature sensing sensor 68, of which the contact point turns off when the internal-temperatures of the second, third, fourth and fifth receiving parts 63b, 63c, 63d and 63e are lower than the set temperature and of which the "©"contact turns on when the internal-temperatures of the second, third, fourth and fifth receiving parts 63b, 63c, 63d and 63e are higher than the set temperature. The "©"contact of the first and second internal-temperature sensing sensors 64a-1 , 64a-2, 64a-3, 64a- 4, 64b-1 , 64b-2, 64b-3, and 64b-4 are connected to each other.

The reason for using two set of the first and second internal-temperature sensing sensors 64a-1~64a-4, 64b-1~64b-4 is that the malfunction of the first and second sensors, which is caused by the weather condition according to the temperature difference of the solar heat. That is, it is detected that the internal- temperature of the second, third, fourth and fifth receiving parts 63b, 63c, 63d, and 63e is maintained at 30°C in a cloudy day and in the spring, the autumn and the winter in which the temperature of the solar heat is relatively low, while the internal- temperature of the second, third, fourth and fifth receiving parts 63b, 63c, 63d, and 63e increases more than 40°C in the summer in which the temperature of the solar heat is relatively high. Thus, the temperature at the operation of the first internal- temperature sensing sensors 64a-1, 64a-2, 64a-3 and 64a-4 is set at 30°C and the temperature at the operation of the second internal-temperature sensing sensors 64b-1 , 64b-2, 64b-3, and 64b-4 is set at 40°C.

Further, an operating temperature of the external-temperature sensor 68 is set at 25°C to selectively drive either the first internal-temperature sensors 64a-1~64b-5 or the second internal-temperature sensors 64b-1~64b-5 according to seasons. Therefore, the first internal-temperature sensors 64a-1 ~64b-5 are operated when the atmosphere temperature is at 25°C or less, and the second internal-temperature sensors 64b-1~64b-5 are operated when the atmosphere temperature is at more than 25°C. And, a diode (D) is connected in a forward direction between the first and second internal-temperature sensors 64a-1~64b-5 and 64b-1~64b-5 and the external-temperature sensor 68 to prevent a reverse current from flowing from the first and second internal-temperature sensors 64a-1~64b-5 and 64b-1~64b-5 to the external-temperature sensor 68. Accordingly, it is possible to prevent the solar tracking apparatus from malfunctioning.

In the present invention, as a matter of convenience, a light receiving area of a sun tracking sensor part 60 is divided into 5 sections (65a~65e), but the number of sections is not limited. It is understood in the art that the more number of sections increase, the higher the tracking accuracy of the ecliptic is. The first through fifth lenses 62a~62e which have a type of convex lens are mounted for collecting sunlight on upper surfaces of each side wall which forms the first through the fifth receiving parts 63a~63e. When conventional plate glasses are used instead of the first through fifth lenses 62a~62e, the efficiency of collecting sunlight degreases. Therefore, two external-temperature sensors are need. Illustrating the light receiving area of the sun tracking sensor part 60 according to the ecliptic with reference to FIG. 2, when the sun (S) is at the position of P1 , the sunlight is received at the first light receiving section 65a which is substantially at a position on a straight line extended from that to the central axis of the sun tracking sensor part 60. When the sun (S) is at the position of P2, the sunlight is received at the second light receiving section 65b that is substantially at a position on a straight line extended from that to the central axis of the sun tracking sensor part 60.

When the sun (S) is at the position of P3 by continually moving along the ecliptic, the sunlight is received at the third light receiving section 65c. When the sun (S) is at the position of P4, the sunlight is received at the fourth light receiving section 65d. And, when the sun (S) is at the position of P5 (sunset position), the sunlight is received at the fifth light receiving section 65e.

Wherein, when the sunlight is irradiated at the first through fifth light receiving sections 61a through 61 e, the first through sixth partitions 61a through 61f have no effect on the near receiving sections, thereby exactly receiving the sunlight along the ecliptic. The sun heat, which is inputted from the first through fifth light receiving sections 61a through 61 e, is collected by the first through fifth lenses 62a through

62e thereby to be irradiated into the first through fifth receiving parts 63a through 63e.

The first and second internal-temperature sensors 64a-1~64b-5 and 64b- 1~64b-5 installed in the second through fifth receiving part 63b through 63e sense the temperature of the sun heat inputted through the second through fifth lenses 61b through 61 e. When the sensed temperature of the sun heat arrives at a set temperature, an electric switch in the first and second internal-temperature sensors 64a-1~64b-5 and 64b-1~64b-5 is switched on, such that a driving power is supplied to a motor 21. When since the sun is out of the receiving sections 61a through 61e, the sensed temperature is less than the set temperature, the electric switch in the first and second internal-temperature sensors 64a-1~64b-5 and 64b-1~64b-5 is switched off.

FIG. 3a shows a rotation sensing part 30. The rotation sensing part 30 is installed at a rotational shaft 25 in a sun tracking apparatus according to the present invention. When a solar collector 40 is rotated at an optimal angle by the electric switch of the sun tracking sensor part 60, the rotation of the motor 21 is stopped by the rotation sensing part 30.

That is, a front panel 31 and a rear panel 32 which have a quadrangular or round shape are spaced from each other and held by a bolt 35. An indicator 33 is installed by a hinge 37 at a central portion of one side surface of the front panel 31 to be rotated. Therefore, the indicator 33 stays on a perpendicular state by the center of gravity of a balance weight 33a even though the rotation sensing part 30 is rotated. A scale 34 is marked on one side surface of the front panel 31 in proportion to the number of the first through fifth light receiving sections 65a through 65e for denoting the rotational sections.

The first through fourth rotation sensing switches 36a through 36d are installed on the rear panel 32 at the positions corresponding to marks of the scales 34. A returning sensing switch 39 is installed on the real panel 32. The returning sensing switch 39 has a function for causing the solar collector 40 to be stopped when the solar collector 40 returns to the position at the time of sunrise after the one operation cycle of the system is completed. An error-sensing switch 38 is also installed on the rear panel 32. The error-sensing switch 38 has a function for preventing an overload of the motor 21 that is generated by continually driving the motor 21 owing to a system hindrance such as a malfunction, abnormal climate, etc. The first through fourth rotation sensing switches 36a through 36d, the returning sensing switch 39, and the error-sensing switch 38 maintain the switched- on state when the balance weight 33a is near them. The first through fourth rotation sensing switches 36a through 36d, the returning sensing switch 39, and the error- sensing switch 38 are switched off to stop the motor 21 when the balance weight 33a is not near them.

Though four rotation sensing switches 36a through 36d are only used in proportion to the numbers of the light receiving sections 65b through 65e for convenience in this embodiment, it is understood in the art that the numbers of rotation sensing switches increase with that of the light receiving sections. (A), (B), (C), (D) and (E) of FIG. 3b are views for showing an operation of the rotation sensing part 30. For describing steps of the operation, assuming that (A) of FIG. 3b is an initial state in which the solar collector 40 is at the position of sunrise. The first through fourth rotation sensing switches 36a through 36d maintain the switched-on state because they are near the balance weight 33a. In the above state, when a contact point outputted from the sun tracking is varied, the motor 21 is driven to rotate the rotational shaft 25 in the counter- clockwise direction. Though as the rotational shaft 25 is rotated, the rotation sensing part 30, which is installed on the rotational shaft 25, is also rotated in the counterclockwise direction, the rotation sensing part 30 keeps in a state perpendicular to the ground. At this time, when the first rotation sensing switch 36a is out of the range of the balance weight 33a which keeps in the state perpendicular to the ground, as shown in (B) of FIG. 3b, as the rotation sensing part 30 is rotated, the first rotation sensing switch 36a is switched off. When the second rotation sensing switch 36b is out of the range of the balance weight 33a, as shown in (C) of FIG. 3b, as the rotation sensing part 30 is continuously rotated, the second rotation sensing switch 36b is switched off.

Further, when the third rotation sensing switch 36c is out of the range of the balance weight 33a, as shown in (D) of FIG. 3b, as the rotation sensing part 30 is continuously rotated, the third rotation sensing switch 36c is switched off. When the fourth rotation sensing switch 36d is out of the range of the balance weight 33a, as shown in (D) of FIG. 3b, as the rotation sensing part 30 is continuously rotated, the fourth rotation sensing switch 36d is switched off.

That is, when the first through fourth rotation sensing switch 36a through 36d are near the indicator 33, the first through fourth rotation sensing switch 36a through 36d are switched on to supply an electric power to the motor 21. However, when the balance weight 33a escapes from the first through fourth rotation sensing switch 36a through 36d, the first through fourth rotation sensing switch 36a through 36d are switched off to cut off the driving electric power of the motor 21.

Therefore, the solar collector 40 exactly keeps track of an orbit of the sun by the rotation sensing part 30, which includes the balance weight 33a and the first through fourth rotation sensing switch 36a through 36d, such that the efficiency of collecting heat can be maximized.

FIG. 4a and FIG. 4b show electric circuits of the sun tracking apparatus according to the present invention. As shown in FIG. 4a, a rectifying part (BD) is connected with a power supply of three-phase AC 220V, and outputs a DC voltage by reducing and rectifying an AC voltage. And, the rectifying part (BD) has output terminals which are connected in parallel with the first and second internal-temperature sensors 64a-1~64b-5 and 64b- 1~64b-5. The first and second internal-temperature sensors 64a-1~64b-5 and 64b- 1~64b-5, each of which is installed in the second through fifth receiving parts 63b through 63e of the sun tracking sensor part 60, are switched on when the sun heat arrives at the set temperature.

The other side ends of the first and second internal-temperature sensors 64a- 1~64b-5 and 64b-1~64b-5 are connected in serial with the first through fourth rotation sensing switches 36a through 36d which are installed in the rotation sensing part 30. When the first through fourth rotation sensing switches 36a through 36d are near the balance weight 33a, the first through fourth rotation sensing switches 36a through 36d maintain the switched on state. When the first through fourth rotation sensing switches 36a through 36d are separated from the balance weight 33a, the first through fourth rotation sensing switches 36a through 36d are switched off. The other side ends of the first through fourth rotation sensing switches 36a through 36d are respectively connected in serial with the first through fourth relays (RY1) through (RY4) for either supplying or cutting off an electric power to the motor 21. The first through fourth relays (RY1) through (RY4) are connected in parallel with the first through fourth lamps (L1) through (L4), respectively. The output terminal of the rectifying part (BD) is connected with the error- sensing switch 38. The error-sensing switch 38 is switched on by the balance weight 33a of the rotation sensing part 30 when the motor 21 is excessively rotated over the orbit of the sun owing to a malfunction of the system. Further, the sixth relay (RY6) is connected in serial with the output terminal of the rectifying part (BD). The sixth relay (RY6) continuously drives the sixth relay switch (RSW6), the ninth relay (RY9), and the ninth relay switch (RSW9) to cause the main magnetic switch (MC) to be switched off, thereby cutting off the electric power of the motor 21.

And, as shown in FIG. 4b, the first through fourth relay switches (RSW1) through (RSW4), which are switched on in driving the first through the fourth relays (RY1) through (RY4), are connected in parallel with the terminal the rectifying part (BD). A timer (TM) is connected with the power of three-phase AC 220V. The timer (TM) is provided for recovering the solar collector 40 into an initial state at the time set by a user. The output terminal of the rectifying (BD) is connected in serial with a timer switch (TSW), the eighth relay (RY8), a returning sensing switch 39, and the seventh relay switch (RSW7a). The timer switch (TSW) is switched on when the timer (TM) counts to the set time. The eighth relay (RY8) is driven by the timer switch (TSW) for providing a reverse voltage to the motor 21 to take the motor 21 into an initial state of the motor 21. The returning sensing switch 39 stops the motor 21 after recovering the motor 21. The eighth relay switch (RSW8a) and the seventh relay (RY7) are connected in serial with the other terminals of the first through fourth relay switches (RSW1) through (RSW4). The eighth relay switch (RSW8a) is switched by the eighth relay (RY8). The seventh relay (RY7) is driven by the switching operation of the eighth relay switch (RSW8a). The seventh and eighth relay switches (RSW7b) and (RSW8b), which are switched by driving of the seventh and eighth relay (RY7) and (RY8), have the other ends which are connected with forward and reward rotation magnetic switches (MSW1) and (MSW2). The forward and reward rotation magnetic switches (MSW1) and (MSW2) provide either a forward voltage or a reward voltage to the motor 21 for rotating the motor in either the forward direction or reward direction.

The reference symbols, (PSW1), (PSW2), (C), (MSW), and (MC) are a main power switch, a supplementary power switch, a rectifying condenser, a magnetic contact, and a main magnetic switch of the motor 21 , respectively.

Operations of the sun tracking apparatus according to the present invention will be described below.

When the main and supplementary power switches (PSW1) and (PSW2) depicted in FIG. 4a and FIG. 4b are switched on, the main magnetic switch (MC) is driven to supply a power to the motor 21. At the same time, the rectifying part (DB) converts the electric power of AC 220V into the DC voltage, such that the first through ninth relays (RY1) through (RY9), the timer (TM), the first through fourth rotation sensing switches 36a through 36d, and the first and second internal- temperature sensors 64a-1~64b-5 and 64b-1~64b-5 are operational. At this state, the timer (TM) is set at the time when the solar collector 40 returns to the initial state that is it has been passed far from the sunset.

Though it is possible to arbitrarily change the set time according to the seasons because the times of sunset and sunrise are varied according to the seasons, we will assume in the present invention that the timer (TM) is set at

21 o'clock for convenience and the current season is in spring, such that the first internal-temperature sensors 64a-1 is operated.

At this state, when the sun moves from the place of P1 (sunrise point) along the orbit after sunrise to arrive at the place of P2 as shown in FIG. 2a, the central portion of the sun tracking sensor part 60 and the sun (S) are on a straight line and the most amount of sunlight is inputted into the second light receiving section 61b among the first through fifth light receiving sections 61a through 61 e. Though the sunlight is inputted to the third through fifth light receiving sections 61c through 61 e, the inputted sunlight to the third through fifth light receiving sections 61c through 61 e is not effect on the internal-temperature sensors installed in the third through fifth receiving parts 63c through 63e because the sunlight is blocked by the first through sixth partitions 61b through 61f.

The sun heat inputted into the second light receiving section 61b is collected by the second lens 61b and radiated into the second receiving part 63b to increase the temperature, such that the external-temperature sensor 68 which senses the atmosphere temperature determines whether the first and second internal- temperature sensors 64a-1 and 64b-1 are driven.

As shown in FIG. 2d, when the temperature of atmosphere is below 25°C, the external-temperature sensing sensor 68 is connected to the " " "contact and thereby it is disposed in operative association with the first internal-temperature sensing sensor 64a-1. Alternatively, when the temperature of atmosphere is above 25°C, the external-temperature sensing sensor 68 is connected to the "©"contact and thereby it is disposed in operative association with the second internal-temperature sensing sensor 64b-1. Furthermore, when the internal-temperature of the second receiving part 63b approaches 30°C due to temperature increase of the second receiving part 63b, the first internal-temperature sensing sensor 64a-1 is connected to the "©"contact. When the second receiving part 63b approaches 40°C due to continuous temperature increase of the second receiving part 63b, the internal switch of the second internal-temperature sensing sensor 64b-1 is connected to the "©"contact. Thereby, D.C. electric current source is output through the first and the second internal-temperature sensing sensors 64a-1 , 64b-1.

In other words, when temperature of atmosphere is below 25°C, a closed circuit is created by means of the external-temperature sensing sensor 68 and the first internal-temperature sensing sensor 64a-1. When temperature of atmosphere is above 25°C, a closed circuit is created by means of the external-temperature sensing sensor 68 and the second internal-temperature sensing sensor 64b-1.

Therefore, as shown in FIG. 4a, if one of the first and the second internal- temperature sensing sensors 64a-1, 64b-1 installed in the first receiving part 63a is connected to the "©"contact (=On-state) by receiving the solar heat at its maximum through the second lens 61b in the second light receiving section 65b, the first relay (RY1) is driven through the first rotation sensing switch 36a of the rotation sensing part 30, which is set to the On-state by approaching of the balance weight 33a at a normal state. As a result, as shown in FIG. 4b, the first relay switch (RSW1) is set to the On-state and the seventh relay (RY7) is operated through the eighth relay switch (RSW8), which is set to the On-state at a normal state. As a result, the eighth relay switch (RSW8) is set to the On-state and then the normal rotation magnet switch (MSW1) is operated. Consequently, the motor 21 rotates in the counter-clockwise direction by receiving the three-phase electric current.

The rotational driving force generated from the motor 21 is transmitted to a reduction gear 18 via the second belt 24b and then it becomes weaken. That is, the rotational speed of the motor 21 is reduced. The reduced rotational driving force is transmitted to a pulley 25a formed at the distal end of the rotational shaft 25 via the second belt 24b and thereby it makes the solar collector 40 fixed to the rotational shaft 25 to be rotated in the counter-clockwise direction.

When the rotational shaft 25 rotates due to rotation of the motor 21 , the rotating sensing sensor 30 installed at the rotational shaft 25 simultaneously rotates in the same rotational direction of the rotational shaft 25. As best seen in FIG. 3A, an indicator 33 and the balance weight 33a are maintained in a state that they are always vertical to the ground due to operation of the hinge 37 and to the center of gravity of the balance weight 33a.

Thereafter, as shown in FIG. 3B, when the first rotation sensing switch 36a of the rotating sensing sensor 30 gets out of contact of the balance weight 33a vertical to the ground due to rotation of the rotational shaft 25, the electric contact of the first rotation sensing switch 36a is changed into the Off-state. Accordingly, as shown in FIGS. 4a and 4b, the first relay (RY1), the first relay switch (RSW1), the seventh relay (RY7) and the seventh relay switch (RSW7b) turn off in sequence. Thereby, the contact of the normal rotation magnet switch (MSW1) is shut off and then the motor 21 is not rotated.

At this time, the solar collector 40 fixed to the rotational shaft 25 is corresponding to the second light receiving section 61b and an angle to the sun and therefore it takes a position capable of absorbing the solar energy at maximum.

Furthermore, as shown in FIG. 2b, when the sun (S) approaches the P3 point as a result of continuous movement in accordance with the orbital thereof, extremely much solar energy is provided on the third partition 61c of the solar tracking sensing part 60. At this time, this solar energy is concentrated by the third lens 61c and then it is illuminated toward the interior of the third receiving part 63c. When one of the first and the second internal-temperature sensing sensors 64a-1, 64b-1 senses a temperature above the predetermined temperature, the internal contact is set to the On-state.

If one of the first and the second internal-temperature sensing sensors 64a-2, 64b-2 installed in the third receiving part 63c is connected at the On-state, the second relay (RY2) is driven through the second rotation sensing switch 36b of the rotation sensing part 30, which is set to the On-state by approaching of the balance weight 33a at a normal state. As a result, as shown in FIG. 4b, the second relay switch (RSW2) is set to the On-state and the seventh relay (RY7) is operated through the eighth relay switch (RSW8), which is set to the On-state at a normal state. As a result, the seventh relay switch (RSW7b) is set to the On-state and then the normal rotation magnet switch (MSW1) is operated. Consequently, the motor 21 rotates in the counter-clockwise direction by receiving the three-phase electric current.

Thereafter, as shown in FIG. 3C, when the second rotation sensing switch 36b of the rotating sensing sensor 30 gets out of contact of the balance weight 33a due to rotation of the rotational shaft 25, the electric contact of the second rotation sensing switch 36b is changed into the Off-state. Accordingly, the second relay (RY2), the second relay switch (RSW2), the seventh relay (RY7) and the seventh relay switch (RSW7b) turn off in sequence. Thereby, the contact of the normal rotation magnet switch (MSW1) is shut off and then the motor 21 is not rotated.

At this time, the solar collector 40 fixed to the rotational shaft 25 is corresponding to the third light receiving section 61c and an angle to the sun and therefore it takes a position capable of absorbing the solar energy at maximum.

Meanwhile, as shown in FIG. 2b, when the sun (S) approaches the P5 point as a result of continuous movement in accordance with the orbital thereof, extremely much solar energy is provided on the third partition 61 e of the solar tracking sensing part 60. At this time, this solar energy is concentrated by the fifth lens 61 e and then it is illuminated toward the interior of the fifth receiving part 63e. When one of the first and the second internal-temperature sensing sensors 64a-4, 64b-4 senses a temperature above the predetermined temperature, the internal contact is set at the On-state. If one of the first and the second internal-temperature sensing sensors 64a-4,

64b-4 installed in the fifth receiving part 63e is connected at the On-state, the fourth relay (RY4) is driven through the fourth rotation sensing switch 36d of the rotation sensing part 30, which is set to the On-state by approaching of the balance weight 33a at a normal state. As a result, as shown in FIG. 4b, the fourth relay switch (RSW4) is set to the On-state and the seventh relay (RY7) is operated through the eighth relay switch (RSWδa), which is set to the On-state at a normal state. As a result, the seventh relay switch (RSW7b) is set to the On-state and then the normal rotation magnet switch (MSW1) is operated. Consequently, the motor 21 rotates in the counter-clockwise direction by receiving the three-phase electric current.

Thereafter, as shown in FIG. 3E, when the fourth rotation sensing switch 36d of the rotating sensing sensor 30 gets out of contact of the balance weight 33a due to rotation of the rotational shaft 25, the electric contact of the second rotation sensing switch 36d is changed into the Off-state. Accordingly, the fourth relay (RY4), the fourth relay switch (RSW4), the seventh relay (RY7) and the seventh relay switch (RSW7b) turn off in sequence. Thereby, the contact of the normal rotation magnet switch (MSW1) is shut off and then the motor 21 is not rotated.

At this time, the solar collector 40 fixed to the rotational shaft 25 is corresponding to the fifth light receiving section 61 e and an angle to the sun and therefore it takes a position capable of absorbing the solar energy at maximum.

If a time set at the timer (TM) for driving the solar tracking apparatus has been passed under the state that the solar collector 40 is set to adsorb the solar light at maximum by coinciding of between the angle of the solar energy and the fifth light receiving section 61 e, the solar collector 40 returns its initial position, in which the first light receiving section 61a is coincide with the solar light angle.

When the time interval, that is twenty-one hour, set at the timer (TM) has passed, then the timer switch (TSW) is set to the On-state as shown in FIG. 4B. Due to this, the eighth relay (RY8) is driven through a returning sensing switch 39, which is set to the On-state by approaching of the balance weight 33a at a normal state, and the seventh relay switch (RSW7b) set to the On-state as a result of setting the seventh relay (RY7) to the Off-state. As a result, the eighth relay switch (RSWδb) is set to the On-state and then the normal rotation magnet switch (MSW2) is operated. Consequently, the motor 21 rotates in the counter-clockwise direction by receiving the three-phase electric current and thereby the solar collector 40 returns its initial position, in which the first light receiving section 61a is coincide with the solar light angle. Thereafter, when the solar collector 40 returns its initial position, which is coincide with the time of sunrise, due to the continuous reverse rotation of the motor 21 , the returning sensing switch 39 installed at the rotating sensing sensor 30 gets out of contact of the balance weight 33a as shown in FIG. 3b (A). Accordingly, the electric contact of the returning sensing switch 39 is changed into the Off-state. Therefore, the eighth relay (RY8) and the eighth relay switch (RSW8) turn off in sequence. Thereby, the contact of the normal rotation magnet switch (MSW2) is shut off and then the motor 21 is not rotated. That is, if the time interval set at the timer (TM) has been passed, the solar collector 40 automatically returns at the position coincided with the time of sunrise. The time of the timer (TM) can be controlled by the user based on the seasons with reference to the length of the day and the night. In the meantime, the solar collector 40 must to be returned at the position coincided with the time of sunrise by reverse rotating the motor 21 at the time that the time set at the timer (TM) is completed after stopping the motor 21 at the fifth light receiving section 61 e. If the solar collector 40 rotates over a rotating range set by the error-sensing switch 38 owing to abnormal operation of the system or a hindrance of the sensor, the supply of electric current for the system is forcibly shut off in order to stop the solar collector 40 so that it is possible to prevent the motor 21 from being damaged.

When the error-sensing switch 38 gets out of contact of the balance weight 33a due to continuous rotation of the motor 21 in the counter-clockwise direction as a result of errors of the sensor or the abnormal operation of the system, the electric contact of the error sensing switch 38 is changed into the Off-state as shown in FIG. 4a. Accordingly, the sixth relay (RY6), the sixth relay switch (RSW6), the ninth relay (RY9) and the ninth relay switch (RSW9), are turned off in sequence. Thereby, the supply of electric current for the system is forcibly shut off so that it is possible to prevent the motor 21 from being damaged.

Hereinafter, a hot-water supply system by using the solar tracking system according to the embodiment of the present invention will be described in detail with reference drawings.

FIG. 5 shows the hot-water supply system by using the solar tracking system. A rounded solar collector 40 for collecting the solar light and for reflecting it in order to generate a high temperature of heat is fixed at the center portion of the rotational shaft 25 in the longitudinal direction of the rotational shaft 25. Heat collecting plates 50 for collecting a heat generated from the solar collector 40 and for heating water using the heat are fixed to the center portion of the solar collector 40. When the rotational shaft 25 is rotated by receiving a driving force generated from the motor 21, the solar collector 40 and the heat collecting plates 50 are simultaneously operated. A hot-water tank 16 for storing a hot-water heated by the solar collector 40 is installed at an upper surface of the lower frame 11 of the body 10. Furthermore, a circulation pump 15 for circulating the hot-water between the hot-water tank 16 and the solar collector 40 is installed at an upper surface of the lower frame 11 of the body 10. A supplementary water tank 19 is disposed at a position adjacent to the upper portion of the solar collector 40. When the hot-water introduced into the hot- water tank 16 is exhausted, water is supplemented with the hot-water tank 16 from the supplementary water tank 19.

FIG. 6 shows the solar collector 40 for the hot-water supply system by using the solar tracking system. The solar collector 40 is provided with the first and the second reflective mirrors 41 , 42 for reflecting the solar light and for collecting the solar energy having the convex shape, respectively. Both distal ends of the first and the second reflective mirrors 41 , 42 are fixed to the upper and the lower supporting rods 43, 44. The upper and the lower supporting rods 43, 44 are fixedly engaged with the vertical supporting rod 45.

The rotational shaft 25 for providing a polar rotation by moving a solar collector 40 using the rotational driving force generated from the motor 21 in accordance with a moving track of the sun just after is installed at the center portion of the upper supporting rod 43. Heat collecting plates 50 for collecting a heat reflected from the first and the second reflective mirrors 41 , 42 are fixed to the center portion of the solar collector 40.

FIGS. 7A and 7b show the heat collecting plates 50 for the hot-water supply system by using the solar tracking system. The heat collecting plate 50 is provided with a zigzag shape of pipe 52 having a diameter of 10~15mm, a heating medium 53 is charged into the pipe 52. Thermal conductive metal plates 54 for receiving the heat reflected from the first and the second reflective mirrors 41,42 and for transmitting it to the pipe 52 are installed at the outer side of the pipe 52 at an alternative pattern. A vacuum reinforced glass 51 is installed at outside of the pipe 52 and the thermal conductive metal plates 54. The vacuum reinforced glass 51 is made of a ferruginous reinforced glass by subjecting the vacuum extruding process. Although the length of the heat collecting plate 50 is not limited, it is preferable to have the same length as that of the first and the second reflective mirrors 41 ,42 of the solar collector 40 in order to maximize the effectiveness of the collecting heat. Preferably, the pipe 52 and the thermal conductive metal plates 54 comprise a copper and the stainless steel. In the hot-water supply system by using the solar tracking system as described above, the solar collector 40 can be disposed at a position which the maximum solar energy is illuminated to the solar collector 40. When the solar energy is illuminated to the front surface of the first and the second reflective mirrors 41,42, it is reflected from the rounded surface of them and then is concentrated at the heat collecting plate 50 installed at the center portion of the solar collector 40. At this time, since the first and the second reflective mirrors 41,42 have a function as convex lens, the solar energy is concentrated to the heat collecting plate 50 and thereby the temperature is increased up to the temperature of 200~500°C.

As shown in FIGS.7A and 7B, the solar energy heated to the temperature of 200~500°C by means of the first and the second reflective mirrors 41 ,42 is concentrate illuminated on the metal plate 54 and the pipe 52 through the vacuum reinforced glass 51. Accordingly, the heat of 200~500°C is applied to the metal plate 54 and thereby the heating medium 53 such as the hot water or the oil introduced into the pipe 52 is indirectly heated. Accordingly, if the hot water, which is the heating medium 53 of the pipe 52, is heated at a predetermined temperature, it is automatically introduced into the hot water tank 16 due to convection of the heat or is forcibly circulated by the circulation pump 15.

As described above, the solar tracking system in accordance with the present invention can precisely trace the pivot orbital of the sun due to simple construction and precise operation thereof and thereby it can obtain the solar energy at maximum. Further, it is possible to construct the hot-water system by installing the solar collector 40 having the first and the second reflective mirrors 41,42 as shown in FIG. 6 and the heat collecting plate 50 as shown in FIGS.7A and 7B. Therefore, it is possible to heat water up to the temperature 150~300°C and to maximize the heating efficiency.

As described above, the solar tracking apparatus according to the present invention is capable of tracking the solar along its orbit, which is made at low cost to be commercially sold, and which increases its efficiency of 30~60% when to be adopted to a water heating apparatus using the solar heat, a solar furnace and a generator using the solar heat, in which a light receiving section is formed to receive the solar light in an optic condition as the orbit of the solar is divided into a plurality of sections, and which includes a sensor part for tracking the orbit of the solar by sensing a temperature of the solar heat collected in the respective light receiving part while driving a motor to rotate a plate for collecting the solar heat along the orbit of the solar, and a rotation sensing sensor for stopping the rotation of the plate for collecting the solar light when the plate reaches at a position of receiving the solar light in the optic condition.

In the water heating apparatus using the solar tracking apparatus according to the present invention, the solar collector includes the first and the second reflective mirrors for reflecting and collecting the solar light, which have a rounded shape and a function of operating as a convex lens, respectively. Further, a solar collecting plate for collecting the solar heat reflected from the first and the second reflective mirrors is installed between the first and the second reflective mirrors. Due to this construction, it is possible to maximize the efficiency of collecting heat. While the present invention has been particularly shown and described with reference to a particular embodiment thereof, it will be understood by those skilled in the art that various changes in form and detail may be effected therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

What is claimed is:

1. A solar tracking system for providing a polar rotation by moving a solar collector 40 in accordance with a moving track of the sun just after tracking the sun, in which the solar collector for collecting solar heat is installed at an upper portion of a body having pluralities of frames and is rotatably fixed on a rotational shaft, the rotational shaft being disposed in operative association with a motor at the upper portion of the body, characterized in that: the solar tracking system comprising a solar tracking sensing part 60, in which the solar tracking sensing part 60 includes an external-temperature sensing sensor 68 being mounted on a supporting rod at one end thereof, a hemisphere-shaped fixture 67 being formed at the center portion of the supporting rod 66, the first to the sixth partitions 61a~61f being installed on an upper surface of the hemisphere- shaped fixture 67, the first to the fifth receiving parts 63a~63e being formed at an internal mediate portion of the first to the sixth partitions 61a~61f by means of side walls positioned there between, and the first to the fifth lens 62a~62e for collecting the solar energy being installed at upper sides of the first to the fifth receiving parts 63a~63e, wherein the first to the sixth partitions 61a~61f are spaced from each other at a predetermined distance, the first internal-temperature sensing sensors 64a- 1~64a-5 and the second internal-temperature sensing sensors 64b-1~64b-5 are installed in the first to the fifth receiving parts 63a~63e, the first internal-temperature sensing sensors 64a-1~64a-5 and the second internal-temperature sensing sensors 64b-1~64b-5 operate in accordance with operating temperatures, which are set in operative association with the external-temperature sensing sensor 68, and they drive the motor 21 by changing their contacts in accordance with the internal- temperatures of the first to the fifth receiving parts 63a~63e, wherein a rotation sensing part 30 having a front panel 31 and a rear panel 32 is installed at one side of the rotational shaft 25, the front panel 31 and the rear panel 32 being spaced from each other and engaged with each other by means of pluralities bolts 35, a notch mark on a scale 34 for showing a rotating section being displayed on the front panel 31 and the rear panel 32, an indicator 33 is pivotally installed at the center portion of the front panel 31 by a hinge 37, the indicator 33 being maintained at its vertical position due to the center of gravity of a balance weight 33a, wherein rotation sensing switches 36a~36d, a returning sensing switch 39 and an error-sensing switch 38 are installed on the rear panel 32 at positions corresponding to the notch mark on a scale 34 displayed on the front panel 31 , the rotation sensing switches 36a~36d make the motor 21 stop by contacting with the balance weight 33a and then being changed to off-state, the returning sensing switch 39 makes the motor 21 stop during returning of the solar collector 40 at its initial position by contacting with the balance weight 33a and then being changed to off-state, and the error-sensing switch 38 shuts off an electric current of the system when an error operation is happened by contacting with the balance weight 33a.

2. A solar tracking system including a solar tracking sensing part 60 and a rotation sensing part 30, in which the solar tracking sensing part 60 includes the first internal-temperature sensing sensors 64a-1~64a-5 and the second internal- temperature sensing sensors 64b-1~64b-5, the rotation sensing part 30 includes rotation sensing switches 36a~36d for making the motor 21 stop by contacting with the balance weight 33a and then being changed to off-state, a returning sensing switch 39 and an error-sensing switch 38, characterized in that: a rectifying part (BD) for rectifying A.C. into D.C. is connected with an electric current source of three-phase A.C. 220V, one ends of the first internal-temperature sensing sensors 64a-1~64a-4 and one ends of the second internal-temperature sensing sensors 64b-1~64b-4 are connected to an output terminal of the rectifying part (BD) with arranging in a row, the first to the fourth rotation sensing switches 36a~36d are connected with the other ends of the first internal-temperature sensing sensors 64a-1~64a-4 and to one ends of the second internal-temperature sensing sensors 64b-1~64b-4 with arranging in series, the first to the fourth relays (RY1-RY4) for supplying the motor with an electric current and for shutting it are connected with the other ends of the first to the fourth rotation sensing switches 36a~36d with arranging in series, one end of the error-sensing switch 38 is connected to the output terminal of the rectifying part (BD), the other end of the error-sensing switch 38 is connected to the sixth relay (RY6) for continuously operating the sixth relay switch (RSW6), the ninth relay (RY9) and the ninth relay switch (RSW9) in order to shut off the electric current to be supplied to the motor 21 by turning off the man magnet switch (MC), the first to the fourth relay switches (RSW1~RSW4) are connected to the output of the rectifying part (BD) and turn on at an On-state during operation of the first to the fourth relays (RY1~RY4), a timer (TM) for setting a time interval required to return an initial state of the solar collector 40 is connected with the electric current source of three-phase AC 220V, a timer switch (TSW), the eighth relay (RY8), a return sensing switch (39) and the seventh relay switch (RSW7a) are connected to the output of the rectifying part (BD) with arranging in series, the eighth relay switch (RSWδa) and the eleventh relay (RY7) are connected to the other end of the first to the fourth relay switches (RSW1~RSW4), the eighth relay switch (RSWδa) operates in accordance with operation of the eighth relay (RY8), the eleventh relay (RY7) operates in accordance with operation of the eighth relay switch (RSWδa), wherein the seventh and the eighth relay switches (RSW7b, RSWδb) are connected with an electric current source of AC 220V and operate in accordance with operations of the eleventh relay (RY7) and the eighth relay (RYδ), a normal rotation magnet switch (MSW1) for rotating the motor 21 in a normal rotational direction and a reverse rotation magnet switch (MSW2) for rotating the motor 21 in a reverse rotational direction are connected to the other ends of the seventh and the eighth relay switches (RSW7b, RSWδb).

3. A hot-water supply system by using a solar tracking system for providing a polar rotation by moving a solar collector 40 in accordance with a moving track of the sun just after tracking the sun, in which the solar collector for collecting solar heat is installed at an upper portion of a body 10 having pluralities of frames and is rotatably fixed on a rotational shaft 25, the rotational shaft 25 being disposed in operative association with a motor 21 at the upper portion of the body 10, the hot- water supply system has a hot-water tank 16 for storing a hot-water heated by the solar collector 40 which is installed at a lower surface of the body 10, a circulation pump 15 for circulating the hot-water between the hot-water tank 16 and the solar collector 40, and a supplementary water tank 19, characterized in that: the solar collector 40 includes the first and the second reflective mirrors 41 ,42 for reflecting and collecting the solar light which have a rounded shape and a function of operating as a convex lens, respectively, both ends of the first and the second reflective mirrors 41 ,42 are fixed by an upper and a lower supporting rods 43,44, the upper and the lower supporting rods being engaged with a vertical supporting rods 45 at their lower surfaces, respectively, a heat collecting plate 50 for collecting the solar heat reflected from the first and the second reflective mirrors 41 ,42 is installed between the first and the second reflective mirrors 41 ,42, the heat collecting plate 50 is provided with a zigzag shape of pipe 52 having a diameter of 10~15mm, a heating medium 53 is charged into the pipe 52, thermal conductive metal plates 54 for receiving the heat reflected from the first and the second reflective mirrors 41,42 and for transmitting it to the pipe 52 are installed at the outer side of the pipe 52 at an alternative pattern, a vacuum reinforced glass 51 is installed at outside of the pipe 52 and the thermal conductive metal plates 54, the vacuum reinforced glass 54 being made of a ferruginous reinforced glass by subjecting the vacuum extruding process.