Abstract:
A solar power generation system according to the present invention comprises heat pipes which are arranged radially on the outer peripheral surface of an absorber to increase heat transfer effectiveness between the absorber and the heat pipes, thereby improving heat transfer efficiency. Also, the solar power generation system has the advantage of operating the system more stably and efficiently even in suddenly changing weather conditions, due to the improved heat transfer efficiency and capability to store heat for a specific amount of time. In addition, when the heat pipes are extrapolated onto the absorber, heat can be transferred more effectively by increasing contact surface area with between the absorber and the heat pipes. Furthermore, heat can be transferred more effectively by increasing the contact surface area by coupling the heat pipes to a heat exchange portion through a block-coupling technique.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a solar power generation system, and more particularly, to a solar power generation system that is capable of improving power generation efficiency by transferring thermal energy collected by a dish type solar concentrator to a thermal conversion electricity generation device more effectively. 
       BACKGROUND ART 
       [0002]    Due to the problem relating to environmental pollution caused by exhausted chemical energy, such as coal or petroleum, and due to the usage of the chemical energy, concerns and endeavors for the development of alternative energy are recently on the rise. Thus, technology development for solar power generation using solar energy that is one alternative energy is required. Solar power generation is technology for converting thermal energy generated by collecting the solar energy into electric energy. A dish type concentrator is mainly used to collect solar heat onto one place. The solar heat collected by the concentrator is absorbed by an absorber and is transferred to a thermal conversion electricity generation device, such as an engine, so that electricity can be generated. 
         [0003]    Korean Patent Registration No. 10-1008500 discloses a concentrator-fixed type solar high-concentration system. 
         [0004]    Recently, in order to convert solar energy into electric energy effectively in solar power generation, technology for converting collected solar heat into electric energy more effectively with a compact structure needs to be developed. 
       DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
       [0005]    The present invention provides a solar power generation system that is capable of further improving efficiency by improving heat transfer capability. 
       Technical Solution 
       [0006]    According to an aspect of the present invention, there is provided a solar power generation system including: a concentrator that collects solar heat; an absorber having a cavity to which solar heat collected by the concentrator is transferred, formed therein; heat pipes that are disposed to surround an outer peripheral surface of the absorber and absorb heat of the absorber; a first heat exchange portion that performs heat-exchanging with the heat pipes and absorbs heat of the heat pipes; and a thermal conversion electricity generator that generates electricity by receiving heat from the first heat exchange portion. 
         [0007]    According to another aspect of the present invention, there is provided a solar power generation system including: a concentrator that collects solar heat; an absorber having a cylindrical shape in which one side of the absorber is open so that a cavity to which solar heat collected by the concentrator is transferred, is formed in the absorber; heat pipes having a bent pipe shape in which a plurality of heat pipes are disposed to surround the periphery of the absorber in the longitudinal direction, a plurality of heat pipes being radially arranged and absorbing heat of the absorber; a first heat exchange portion including a circulation pipe in which a circulation fluid that circulates by performing heat-exchanging with the heat pipes and by absorbing heat is filled, and a casing formed to surround the circulation pipe and the heat pipes; and an alkali metal thermal to electric converter (AMTEC) that is disposed so that the circulation pipe passes through the AMTEC and that generates electricity by receiving heat from the circulation pipe. 
         [0008]    According to still another aspect of the present invention, there is provided a solar power generation system including: a concentrator that collects solar heat; an absorber having a cylindrical shape in which one side of the absorber is open so that a cavity to which solar heat collected by the concentrator is transferred, is formed in the absorber; heat pipes having a cylindrical shape in which a front side of each of the heat pipes is open so that the heat pipes are mounted on an outer peripheral surface of the absorber and in which uneven portions are formed on a rear side of each heat pipe and which absorbs heat of the absorber; a first heat exchange portion including a circulation pipe in which a circulation fluid that circulates by performing heat-exchanging with the heat pipes and by absorbing heat is filled, and a casing in which uneven portions are formed on one side surface of the casing to correspond to uneven portions of the heat pipes so that the casing is coupled to the heat pipes through a block-coupling technique and which is configured so that the circulation pipe is in communication with the casing; and an alkali metal thermal to electric converter (AMTEC) that is disposed so that the circulation pipe passes through the AMTEC and that generates electricity by receiving heat from the circulation pipe. 
       Advantageous Effects 
       [0009]    In a solar power generation system according to the present invention, heat pipes are arranged radially on an outer peripheral surface of an absorber so that heat transfer between the absorber and the heat pipes can be performed more effectively and thus heat transfer efficiency can be improved. 
         [0010]    In addition, since the heat pipes are arranged to surround the absorber, a heat storing capability of the absorber is improved so that a system can be operated more stably and efficiently even in suddenly changing weather conditions. 
         [0011]    Furthermore, the heat pipes are mounted on the outer peripheral surface of the absorber so that a contact surface area between the absorber and the heat pipes is increased and heat transfer can be performed more efficiently. 
         [0012]    Also, the heat pipes are coupled to a heat exchange portion through a block-coupling technique so that the contact surface area is increased and heat transfer can be performed more efficiently. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a view schematically illustrating a configuration of a solar power generation system according to a first embodiment of the present invention. 
           [0014]      FIG. 2  is a perspective view of an absorber including heat pipes illustrated in FIG. 
           [0015]      FIG. 3  is a front view of the absorber illustrated in  FIG. 2 . 
           [0016]      FIG. 4  is a side view of the absorber illustrated in  FIG. 2 . 
           [0017]      FIG. 5  is a rear view of the absorber illustrated in  FIG. 2 . 
           [0018]      FIG. 6  is a view schematically illustrating a configuration of a solar power generation system according to a second embodiment of the present invention. 
           [0019]      FIG. 7  is a cross-sectional view of an absorber including heat pipes illustrated in  FIG. 6 . 
           [0020]      FIG. 8  is a perspective view of the front of the heat pipes illustrated in  FIG. 7 . 
           [0021]      FIG. 9  is a perspective view of the rear of the heat pipes illustrated in  FIG. 7 . 
       
    
    
     MODE OF THE INVENTION 
       [0022]    Hereinafter, a solar power generation system according to embodiments of the present invention will be described in detail with reference to the attached drawings. 
         [0023]      FIG. 1  is a view schematically illustrating a configuration of a solar power generation system  10  according to a first embodiment of the present invention.  FIG. 2  is a perspective view of an absorber including heat pipes illustrated in  FIG. 1 .  FIG. 3  is a front view of the absorber illustrated in  FIG. 2 .  FIG. 4  is a side view of the absorber illustrated in  FIG. 2 .  FIG. 5  is a rear view of the absorber illustrated in  FIG. 2 . 
         [0024]    Referring to  FIG. 1 , the solar power generation system  10  includes a dish type concentrator  20 , an absorber  30 , heat pipes  40 , a first heat exchange portion  50 , a second heat exchange portion  60 , and a thermal conversion electricity generator  70 . 
         [0025]    The dish type concentrator  20  is also referred to as a parabolic reflector and collects solar heat  2  onto one place. The dish type concentrator  20  is disposed to be on the opposite side of a cavity  31  that will be described below so that the solar heat is collected in the cavity  31  through the dish type concentrator  20 . 
         [0026]    The absorber  30  is disposed to be on the opposite side of the dish type concentrator  20 . The absorber  30  has a cylindrical shape in which the cavity  31  is formed in a center of the absorber  30 . Hereinafter, in the current embodiment, the absorber  30  has a cylindrical shape. The absorber  30  includes a cylindrical portion  30   a , a front side of which facing the dish type concentrator  20  is open and which has the cavity  31  formed therein, and a curved surface portion  30   b  that extends backward from the cylindrical portion  30   a  and is rounded with a predetermined curvature. 
         [0027]    A plurality of seating grooves  30   c  are formed in an outer peripheral surface of the cylindrical portion  30   a  so that a plurality of heat pipes  40  that will be described below can be seated in the plurality of seating grooves  30   c . The plurality of seating grooves  30   c  are radially formed to correspond to the plurality of heat pipes  40 . The plurality of seating grooves  30   c  are respectively formed long in a longitudinal direction of the cylindrical portion  30   a  and then extend up to the curved surface portion  30   b.    
         [0028]    Referring to  FIGS. 2 through 5 , the heat pipes or heat-transfer pipes  40  are also referred to as heat-transfer pipes, and an one-side end portion of each of the heat pipes  40  is a heating end, and the other-side end portion of each heat pipe  40  is a cooling end so that the heat pipes  40  transfer heat from the heating end to the cooling end. The heat pipes  40  may also be formed in a pipe or chamber form. A working fluid is sealed in the heat pipes  40 . Sodium, methanol, acetone, water, or mercury may be used as the working fluid. Vapor heated and evaporated at the heating end of the heat pipe  40 , flows toward the cooling end and is condensed. A condensate is returned to the heating end by a capillary force through a wick formed on an inner wall surface of the heat pipe  40 . In the current embodiment, each of the heat pipes  40  has a pipe shape. 
         [0029]    The plurality of heat pipes  40  are radially arranged to surround the outer peripheral surface of the absorber  30 . The heat pipes  40  surround all of sides and a rear side of the absorber  30  and have a bent pipe shape that is bent along the outer peripheral surface of the absorber  30 . That is, each of the plurality of heat pipes  40  includes a rectilinear pipe portion  40   a  that is disposed long in the longitudinal direction of the cylindrical portion  30   a  of the absorber  30  and a bent pipe portion  40   b  that extends from the rectilinear pipe portion  40   a  and is bent to correspond to the curved surface portion  30   b . The rectilinear pipe portion  40   a  serves as a heating end heated by heat absorbed by the absorber  30 , and the bent pipe portion  40   b  serves as a cooling end cooled by transferring heat to a circulation pipe  52  that will be described below. Referring to  FIG. 5 , the bent pipe portions  40   b  of the heat pipes  40  are disposed to be collected in the center of the curved surface portion  30   b  that is a rear side of the absorber  30 . The bent pipe portions  40   b  of the heat pipes  40  collected in the center of the curved surface portion  30   b  transfer heat to the circulation pipe  52  that will be described below and thus are cooled. 
         [0030]    Referring to  FIG. 1 , the first heat exchange portion  50  includes the circulation pipe  52  and a casing  54 . 
         [0031]    A circulation fluid is filled in the circulation pipe  52 . A case where the circulation fluid is water, will be described. However, the present invention is not limited thereto, and a heat pipe may also be used as the circulation pipe  52 . A part of the circulation pipe  52  is disposed adjacent to the cooling end of the heat pipe  40 . The circulation pipe  52  is configured to guide the circulation fluid evaporated by absorbing heat from the heat pipes  40  toward the thermal conversion electricity generator  70  and to circulate the circulation fluid condensed when heat of the circulation fluid is taken away from the thermal conversion electricity generator  70 , toward the heat pipes  40  again. 
         [0032]    An auxiliary cooler  56  that cools the circulation fluid condensed from the second heat exchange portion  60  that will be described below at a set temperature is installed in the circulation pipe  52 . The auxiliary cooler  56  maintains the temperature of the circulation fluid that circulates in the circulation pipe  52  at a constant level. 
         [0033]    The casing  54  is formed to surround the heat pipes  52  so that the circulation pipe  52  can be in communication with the casing  54 . The casing  54  insulates the heat pipes  52  so that heat-exchanging between the heat pipes  52  and the circulation pipe  52  can be well performed. 
         [0034]    The second heat exchange portion  60  is a heat exchanger that connects the circulation pipe  52  and the thermal conversion electricity generator  70  and performs heat-exchanging between the circulation pipe  52  and the thermal conversion electricity generator  70 . The circulation pipe  52  passes through the second heat exchange portion  60  and transfers heat to the thermal conversion electricity generator  70 . 
         [0035]    An alkali metal thermal to electric converter (AMTEC) is used as the thermal conversion electricity generator  70 . The AMTEC is a device that directly converts thermal energy into electric energy. In the AMTEC, if there is a temperature difference between both ends of a beta alumina solid electrolyte having ion conductivity, a difference in vapor pressures of liquid sodium filled in cells becomes a driving force so that sodium ions are moved into a gap between loosely-coupled lattice oxygen. The sodium ions that pass through the electrolyte are neutralized on an electrode surface when a condensation process is performed, so that electricity can be generated. 
         [0036]    Also, the solar power generation system  10  further includes a temperature sensor (not shown) that measures a temperature of the circulation fluid of the circulation pipe  52  that passes through the second heat exchange portion  60  and a controller (not shown) that controls an operation of the auxiliary cooler  56  according to the temperature measured by the temperature sensor (not shown). 
         [0037]    An operation of the solar power generation system having the above configuration according to the first embodiment of the present invention will be described below. 
         [0038]    The solar heat  2  is collected into the cavity  31  of the absorber  30  using the dish type concentrator  20 . 
         [0039]    The heat pipes  40  absorb heat of the solar heat  2  collected into the cavity  31 . Since the plurality of heat pipes  40  are arranged radially on the outer peripheral surface of the absorber  30 , heat can be transferred more effectively from the absorber  30  to the heat pipes  40 . Also, since the first heat pipes  40  surround the absorber  30 , a heat storing effect can be attained by the absorber  30 . 
         [0040]    The working fluid in the heat pipes  40  is evaporated by absorbing heat from the cavity  31 . The evaporated working fluid is moved to the bent pipe portion  40   b  that serves as a cooling end. 
         [0041]    Heat-exchanging with the circulation pipe  52  is performed at the bent pipe portion  40   b  of the heat pipe  40 . The working fluid in the heat pipes  40  is condensed by depriving heat, and the condensed working fluid is moved to the rectilinear pipe portion  40   a  that serves as a heating end, through a wick in the heat pipe  40 . 
         [0042]    The circulation fluid in the circulation pipe  52  is evaporated by absorbing heat from the heat pipes  40 . The evaporated circulation fluid is moved to the second heat exchange portion  60 . 
         [0043]    Heat-exchanging between the circulation pipe  52  and the thermal conversion electricity generator  70  is performed by the second heat exchange portion  60 . The circulation fluid in the circulation pipe  52  is condensed when heat of the circulation fluid is taken away from the thermal conversion electricity generator  70 , and then circulates toward the casing  54 . 
         [0044]    The thermal conversion electricity generator  70  generates electricity using heat transferred from the circulation pipe  52 . 
         [0045]    In this case, when heat-exchanging between the circulation pipe  52  and the thermal conversion electricity generator  70  is not sufficiently performed, the temperature of the circulation fluid in the circulation pipe  52  that passes through the second heat exchange portion  60  is higher than a predetermined set temperature. The controller (not shown) operates the auxiliary cooler  56  to lower the temperature of the circulation fluid in the circulation pipe  52  that passes through the second heat exchange portion  60 . Thus, since the temperature of the circulation fluid in the circulation pipe  52  can be maintained at a constant level, heat-exchanging can be efficiently performed even by the first heat exchange portion  50 . 
         [0046]      FIG. 6  is a view schematically illustrating a configuration of a solar power generation system according to a second embodiment of the present invention.  FIG. 7  is a cross-sectional view of an absorber including heat pipes illustrated in  FIG. 6 .  FIG. 8  is a perspective view of the front of the heat pipes illustrated in  FIG. 7 .  FIG. 9  is a perspective view of the rear of the heat pipes illustrated in  FIG. 7 . 
         [0047]    Referring to  FIG. 6 , a solar power generation system  100  according to the second embodiment of the present invention is different from the solar power generation system  10  according to the first embodiment in that the solar power generation system  100  includes a dish type concentrator  120 , an absorber  130 , heat pipes  140 , a first heat exchange portion  150 , a second heat exchange portion  160  and a thermal conversion electricity generator  170  and each of the heat pipes  140  has a cylindrical shape in which one side of each of the heat pipes  140  is open, so that the heat pipes  140  are mounted on an outer peripheral surface of the absorber  130 . The difference will now be described in detail. 
         [0048]    The absorber  130  is disposed to be on the opposite side of the dish type concentrator  120  and has a cylindrical shape in which a front side of the absorber  130  is open and a cavity  131  is formed in a center of the absorber  130 . Hereinafter, in the current embodiment, the absorber  130  has a cylindrical shape. A stepped portion  130   a  is formed in at least a part of the outer peripheral surface of the absorber  130  so that the heat pipes  140  are mounted on an outer peripheral surface of the absorber  130 . 
         [0049]    Referring to  FIGS. 7 through 9 , the heat pipes  140  has a cylindrical shape in which the front side of each heat pipe  140  is open so that the heat pipes  140  are mounted on an outer peripheral surface of the absorber  130 . Each of the heat pipes  140  has a shape corresponding to the absorber  130 . In the current embodiment, the absorber  130  has a cylindrical shape. Thus, each of the heat pipes  140  also has a cylindrical shape. 
         [0050]    The heat pipes or heat-transfer pipes  140  are also referred to as heat-transfer pipes, and an one-side end portion of each of the heat pipes  140  is a heating end, and the other-side end portion of each heat pipe  140  is a cooling end so that the heat pipes  140  transfer heat from the heating end to the cooling end. A working fluid is sealed in the heat pipes  140 . Methanol, acetone, water, or mercury may be used as the working fluid. Vapor heated at the heating end of the heat pipe  140  and evaporated, flows toward the cooling end and is condensed. A condensate is returned to the heating end by a capillary force through a wick  144  formed on an inner wall surface of the heat pipe  140 . 
         [0051]    The front of each of the heat pipes  140  is mounted on an outer peripheral surface of the absorber  130 , and the rear of each heat pipe  140  is coupled to the first heat exchange portion  150 . That is, an outer circumferential surface of each heat pipe  140  is mounted on the outer peripheral surface of the absorber  130  and serves as a heating end heated by heat of the absorber  130 , and a rear side of each heat pipe  140  serves as a cooling end cooled when heat of the heat pipe  140  is taken away from the first heat exchange portion  150 . 
         [0052]    A coupling portion  141  is formed in the front of the heat pipe  140  and is mounted on an outer peripheral surface of the stepped portion  130   a  and is coupled to the stepped portion  130   a.    
         [0053]    A first uneven portion  142  is formed on the rear side of the heat pipe  140 . The first uneven portion  142  of the heat pipe  140  is coupled to the casing  154  of the first heat exchange portion  150  that will be described below through a block-coupling technique. The heat pipes  140  and the casing  154  are coupled to each other through the block-coupling technique so that a heat transfer area between the heat pipes  140  and the casing  154  is increased and heat transfer efficiency can be improved. 
         [0054]    The first heat exchange portion  150  includes a circulation pipe  152  and the casing  154 . 
         [0055]    A circulation fluid is filled in the circulation pipe  152 . A case where the circulation fluid is water, will be described below. However, the present invention is not limited thereto, and a heat pipe may also be used as the circulation pipe  152 . The circulation pipe  152  is configured to guide the circulation fluid evaporated when heat of the circulation fluid is taken away heat from the heat pipe  410 , toward the thermal conversion electricity generator  170  and to circulate the circulation fluid condensed when heat of the circulation fluid is taken away heat from the thermal conversion electricity generator  170 , toward the heat pipes  140  again. 
         [0056]    An auxiliary cooler  156  that cools the circulation fluid condensed from the second heat exchange portion  160  that will be described below at a set temperature is installed in the circulation pipe  152 . The auxiliary cooler  156  maintains a temperature of the circulation fluid that circulates in the circulation pipe  152  at a constant level. 
         [0057]    The casing  154  includes a second uneven portion  154   a  that is formed on a surface corresponding to the first uneven portion  142  of the heat pipe  140  so that the first uneven portion  142  and the second uneven portion  154   a  can be coupled to each other through the block-coupling technique. 
         [0058]    The second heat exchange portion  160  is a heat exchanger that connects the circulation pipe  152  and the thermal conversion electricity generator  170  and performs heat-exchanging between the circulation pipe  152  and the thermal conversion electricity generator  170 . The circulation pipe  152  passes through the second heat exchange portion  160  and transfers heat to the thermal conversion electricity generator  170 . 
         [0059]    An AMTEC is used as the thermal conversion electricity generator  170 . The AMTEC is a device that directly converts thermal energy into electric energy. In the AMTEC, if there is a temperature difference between both ends of a beta alumina solid electrolyte having ion conductivity, a difference in vapor pressures of liquid sodium filled in cells becomes a thrust force so that sodium ions are moved into a gap between loosely-coupled lattice oxygen. The sodium ions that pass through the electrolyte are neutralized on an electrode surface when a condensation process is performed, so that electricity can be generated. 
         [0060]    Also, the solar power generation system  100  further includes a temperature sensor (not shown) that measures a temperature of the circulation fluid of the circulation pipe  152  that passes through the second heat exchange portion  160  and a controller (not shown) that controls an operation of the auxiliary cooler  156  according to the temperature measured by the temperature sensor (not shown). 
         [0061]    In the solar power generation system  100  having the above configuration according to the second embodiment of the present invention, the heat pipes  140  are mounted on the outer peripheral surface of the absorber  130  and are coupled to the absorber  130  so that a contact surface area between the absorber  130  and the heat pipes  140  is increased and heat transfer can be performed more efficiently. 
         [0062]    In addition, since the heat pipes  140  and the first heat exchange portion  150  are coupled to each other through the block-coupling technique, the contact surface area between the heat pipes  140  and the first heat exchange portion  150  is increased so that heat transfer can be performed more effectively. 
         [0063]    As described above, a heat storing capability and heat transfer efficiency are increased so that a system can be operated more stably and effectively even in weather conditions in which an amount of solar radiation changes suddenly. 
         [0064]    While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. 
       INDUSTRIAL APPLICABILITY 
       [0065]    According to the present invention, a solar power generation system that is capable of improving heat transfer efficiency by performing heat transfer more effectively can be manufactured.