Abstract:
A solar energy collecting assembly useful for transferring solar heat to a heat utilizing system via heat transfer fluid flow, comprising anisotropic graphite sheets coupled to a pipe containing heat transfer fluid, and various configurations and embodiments. Methods useful for extracting collected solar heat and transferring said heat to a heat transfer medium.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a non-provisional patent application claiming benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 60/935,735, filed Aug. 29, 2007, the entire contents of which are hereby expressly incorporated by reference into this disclosure as if set forth fully herein. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to energy converters and more particularly to solar energy collectors. 
     BACKGROUND OF THE INVENTION 
     A solar collector is a device for extracting the energy of the sun directly into a more usable or storable form. The energy in sunlight is in the form of electromagnetic radiation from the infrared (long) to the ultraviolet (short) wavelengths. The solar energy striking the earth&#39;s surface at any one time depends on weather conditions, as well as location and orientation of the surface, but overall, it averages about 1000 watts per square meter on a clear day with the surface directly perpendicular to the sun&#39;s rays. 
     A solar thermal collector that stores heat energy is called a “batch” type system. Other types of solar thermal collectors do not store energy but instead use fluid circulation (usually water or antifreeze solutions or refrigerants) to transfer the heat for direct use or storage in an insulated reservoir. Heat transfer medium/glycol has a high thermal capacity and is therefore convenient to handle. The direct radiation is captured using a dark colored surface which absorbs the radiation as heat and conducts it to the transfer fluid. Metal makes a good thermal conductor, especially copper and aluminum. 
     The fluid carries away the absorbed heat, thus cooling the absorber. The warmed fluid leaving the collector is either directly stored, or else passes through a heat exchanger to warm another tank of heat transfer medium, or is used to heat a building directly. 
     The transfer of heat is normally from a high temperature object to a lower temperature object. Classical transfer of thermal energy occurs only through conduction, convection, radiation or any combination of these. Conduction can be defined as a transfer of heat by electron diffusion or phonon vibrations, convection as a transfer of heat by conduction in a moving medium, such as a fluid, and radiation as a transfer of heat by electromagnetic radiation or, equivalently, by photons. 
     Conduction is heat transfer without any motion of the material as a whole. If one end of a metal rod is at a higher temperature, then energy will be transferred from a hot part of a body toward a colder one because the higher speed particles will collide with the slower ones with a net transfer of energy to the slower ones. For heat transfer between two plane surfaces, such as heat loss through the wall of a house, the rate of conduction heat transfer is: 
               Q   t     =       kA   ⁡     (       T   hot     -     T   cold       )       d           
Q is heat transferred in time t, k is thermal conductivity of a thermal conductor, A is an area of a body cross section, T hot  and T hot  are temperatures of hot and cold edges of the body, respectively, d is a distance between hot and cold edges.
 
     The design concept used for heating and cooling systems is similar. Materials with high thermal conductivity are used in both systems. 
     U.S. Pat. No. 4,459,976 discloses a heat exchanger/solar collector. An absorbing element is a thin radiation-absorbing layer composed of particles of crystalline graphite in light-transparent plate-type container. Heat-removing results from heat transfer medium flowing between particles of crystalline graphite. 
     US Application 2007/0158050 teaches a microchannel heat sink made of graphite material. A heat sink member has a plurality of microchannels formed therein for carrying heat transfer medium heat transfer medium. The each microchannel has a length parallel to outer surfaces of the heat sink member. 
     These two technical solutions have similar disadvantages in terms of application of them in solar heat collecting devices. The solar heat collector taught in &#39;976, requires quite powerful heat removal (in terms of watts) and consequently large heat transfer medium flow. The heat sink solution taught in &#39;050 suggested for smaller bodies such as electronic components uses microchannels to cool the body. Microchannels provide, however high resistance to fluid flow. Thus both of the above mentioned technical solutions are not optimally effective for use in solar heat collecting devices. Additionally, the microchannel devices are likely to fail in long-term usage because they will become clogged by dissolved salts in circulating heat transfer medium. 
     Graphite sheets are a potentially useful material, due to their anisotropic properties, specifically anisotropic thermal conductivity. Thermal conductivity of graphite sheets in a direction parallel to the crystallographic plane is several-fold higher in comparison with other directions. 
     Anisotropy in thermal conductivity of graphite sheets is used in a heat sink made of longer and shorter graphite sheets, see U.S. Pat. No. 6,771,502. A heat sink apparatus comprises alternating longer and shorter sheets of graphite material sandwiched together such that the longer sheets extend beyond the shorter sheets to define fins. The directions of higher thermal conductivity of the anisotropic graphite material are oriented in the plane of the sheet. The longer and shorter sheets have base ends aligned together to define a generally planar base surface for engaging an electronic device to be cooled. 
     The heat sink cooling taught in &#39;502 is implemented by air convection which is the least effective type of heat transfer. Additionally, graphite sheets are attached to the cooled surface by means of end face surfaces of graphite sheets only. Enhancement of the area of thermal contact would facilitate an increased heat transfer rate. 
     An efficient means and method of extraction of converted heat from solar collecting devices is hence still a long felt need. 
     SUMMARY OF THE INVENTION 
     It is hence one object of the invention to disclose a solar energy collecting assembly for a solar energy converter comprising at least one graphite sheet and at least one pipe coupled to a heat utilizing system. An end face surface of the graphite sheet thermally attached to a surface of the pipe. A heat utilizing system is adapted to extract collected solar heat by means of circulation of a heat transfer medium. It is a core disclosure of the invention to disclose a pipe furnished with slit-like ports adapted to hold a crenulated or other conveniently shaped edge of the graphite sheet. 
     The comb-type edge elements protrude into the pipe and provide thermal contact with higher efficiency due to additional turbulence inside the pipe. 
     Another object of the invention disclosed herein is a device wherein the thermal transfer medium is water. 
     Another object of the invention is to disclose a solar energy collecting assembly for a solar energy converter comprising at least one graphite sheet and at least one pipe coupled to a heat utilizing system. An end face surface of the graphite sheet is thermally attached to a surface of the pipe. The heat utilizing system is adapted to extract collected solar heat by means of circulation of a heat transfer medium. It is in the core of the invention wherein the pipe has at least invagination located along the pipe and adapted to hold the graphite sheet. 
     Another object of the invention is to disclose a solar energy collecting assembly for a solar energy converter comprising at least one graphite sheet and at least one pipe coupled to a heat utilizing system. The heat utilizing system is adapted to extract collected solar heat by means of circulation of a heat transfer medium. It is in the core of the invention wherein a heat transfer adaptor is disposed between the pipe and the graphite sheet; the adaptor has a plurality of pins penetrating into the graphite sheet and providing a thermal contact between the graphite sheet and the adaptor. 
     Another object of the invention is to disclose a thermal device for heating and/or cooling surrounding air comprising at least one graphite sheet and at least one pipe coupled to a heating and/or cooling system. A thermal device further comprises an end face surface of the graphite sheet thermally attached to a surface of the pipe. The heating and/or cooling system is adapted to extract heat from the graphite sheet and provide heat the graphite sheet by means of circulation of a thermal transfer medium. It is in the core of the invention wherein the pipe is furnished with slit-like ports adapted to hold a crenulated edge (or any other conveniently shaped edge) of the graphite sheet such that elements of the crenulated edge protrude into the pipe providing thermal contact with higher efficiency due to additional turbulence inside the pipe. 
     Another object of the invention is to disclose a thermal device for heating and/or cooling surrounding air comprising at least one graphite sheet and at least one pipe coupled to a heating and/or cooling system. A thermal device further comprises an end face surface of said graphite sheet thermally attached to a surface of the pipe. The heating-cooling system is adapted to extract heat from the graphite sheet and provide heat to the graphite sheet by means of circulation of a thermal transfer medium. It is in the core of the invention wherein the pipe has at least one invagination disposed along the pipe and adapted to hold the graphite sheet. 
     Another object of the invention is to disclose a thermal device for heating and/or cooling surrounding air comprising at least one graphite sheet and at least one pipe coupled to a heating and/or cooling system. A thermal device further comprises an end face surface of the graphite sheet thermally attached to a surface of the pipe. The heating and/or cooling system is adapted to extract heat from the graphite sheet and provide heat to the graphite sheet by means of circulation of a thermal transfer medium. It is in the core of the invention further wherein a heat transfer adaptor is disposed between the pipe and the graphite sheet. The adaptor has a plurality of pins penetrating into the graphite sheet and providing a thermal contact between the graphite sheet and the adaptor. 
     Another object of the invention is to disclose a solar energy collecting assembly for a solar energy converter constituting plane housing and comprising metal and plastic plates disposed in parallel against each other and sealed along their perimeter. The housing has input and an output ports coupled to a heat utilizing system for inflowing and outflowing the heat transfer agent. The heat conducting metal plate is coated with a coating for absorbing solar rays. It is in the core of the invention wherein the plastic plate has grooves extruded on the inner side. The groves provide passages for the heat transfer agent. A surface of the grooves is sufficiently rough to provide turbulence in a flow of the heat transfer agent. 
     Another object of the invention is to disclose a solar energy collecting assembly for a solar energy converter constituting plane housing and comprising metal and plastic plates disposed in parallel against each other and sealed along their perimeter. The housing has input and an output ports coupled to a heat utilizing system for inflowing and outflowing heat transfer agent. The heat conducting metal plate is coated with a coating absorbing solar rays. It is in the core of the invention wherein graphite spacers are disposed between the plastic and metal plates; the graphite spacers are adapted to provide passages for the heat transfer agent; the plastic plate has sufficiently roughness adapted to provide turbulence in a flow of the heat transfer agent. 
     Another object of the invention is to disclose a solar energy collecting assembly for a solar energy converter constituting plane housing and comprising two heat conducting metal plates disposed in parallel against each other and sealed along their perimeter. 
     The housing has an input and an output ports coupled to a heat utilizing system for inflowing and outflowing heat transfer agent; at least one heat conducting metal plates is coated with a coating absorbing solar rays. It is in the core of the invention wherein graphite spacers are disposed between the metal plates; the graphite spacers are adapted to provide passages for said heat transfer agent. 
     Another object of the invention is to disclose a solar energy collecting assembly for a solar energy converter constituting plane housing and comprising two graphite sheets disposed in parallel against each other and sealed along their perimeter. The housing has an input and an output ports coupled to a heat utilizing system for inflowing and outflowing heat transfer agent. It is in the core of the invention wherein graphite sheets have grooves adapted to provide passages for said heat transfer agent. 
     Another object of the invention is to disclose an improved solar energy collecting assembly for a solar energy converter comprising at least one solar energy collecting element and at least one pipe coupled with a heat utilizing system in thermal contact with said solar energy collector wherein improvement comprises usage of a graphite sheet as said solar energy collecting element; said pipe is furnished with slit-like ports adapted to hold a crenulated (or any other conveniently shaped edge) edge of the graphite sheet. Elements of the crenulated edge penetrate into the pipe and provide thermal contact with higher efficiency due to additional turbulence of flow of a thermal carrier medium inside said pipe. 
     Another object of the invention to disclose an improved solar energy collecting assembly for a solar energy converter comprising at least solar energy collecting element and at least one pipe coupled with a heat utilizing system in thermal contact with the solar energy collector. It is in the core of the invention wherein improvement comprises usage of a graphite sheet as the solar energy collecting element. The pipe is furnished with slit-like ports adapted to hold a crenulated (or any other convenient shape) edge of the graphite sheet; elements of the crenulated edge penetrate into the pipe and provide a thermal contact with higher efficiency due to additional turbulence of flow of a thermal carrier medium inside the pipe. 
     A further object of invention is to disclose an improved solar energy collecting assembly for a solar energy converter comprising at least solar energy collecting element and at least one pipe coupled with a heat utilizing system and thermal contacted with the solar energy collector. It is in the core of the invention wherein improvement comprises usage of a graphite sheet as the solar energy collecting element. The pipe has at least one invagination disposed along the pipe and adapted to hold the graphite sheet. 
     Another further object of invention is to disclose an improved solar energy collecting assembly for a solar energy converter comprising at least solar energy collecting element and at least one pipe coupled with a heat utilizing system in thermal contact with the solar energy collector. It is in the core of the invention wherein an embodiment comprises usage of a graphite sheet as the solar energy collecting element; a heat transfer adaptor is disposed between the pipe and the graphite sheet; the adaptor has a plurality of pins penetrating into the graphite sheet and providing a thermal contact between the graphite sheet and the adaptor. 
     Yet another object of invention is to disclose a method useful for extracting collected solar heat and transferring the heat to a heat transfer medium comprising steps of
         a. obtaining at least one graphite sheet, the sheet anisotropically conductive along the crystalline plane,   b. shaping at least one edge of graphite sheet to a crenulated shape (or any other convenient shape),   c. obtaining at least one pipe,   d. furnishing the pipe with slit like ports so as to accommodate the crenulated shape of graphite sheet.   e. attaching the graphite sheet crenulated edge to the pipe such that a portion of the crenulations protrude into the pipe interior, further;   f. providing the attachment with appropriate thermal contact,   g. coupling the pipe to heat utilization system,   h. circulating a heat transfer medium through the pipe, the pipe thereby extracting the collected solar heat and transferring it to the heat utilization system.   i. coupling the pipe to a heat utilizing system.       

     A still further object of invention is to disclose a method useful for extracting collected solar heat and transferring said heat to a heat transfer medium comprising steps of
         a. obtaining at least one graphite sheet, the sheet anisotropically conductive along crystalline plane,   b. obtaining at least one pipe,   c. furnishing said pipe with at least one invagination located along Further another object of invention is to disclosure pipe,   d. attaching the graphite sheet to pipe such that an edge of graphite sheet protrudes into the invagination, further;   e. providing the attachment with appropriate thermal contact,   f. coupling the pipe to heat utilization system,   g. circulating a heat transfer medium through the pipe, the pipe thereby extracting the collected solar heat and transferring it to the heat utilization system.   h. coupling the pipe to a heat utilizing system.       

     Lastly, another object of invention is to disclosure a method useful for extracting collected solar heat and transferring the heat to a heat transfer medium, wherein the method comprises steps of
         a. obtaining at least one graphite sheet, the sheet anisotropically conductive along crystalline plane,   b. obtaining at least one pipe,   c. obtaining an adaptor furnished with a grip and a plurality of pins,   d. attaching the adaptor to said graphite sheet such that the plurality of pins penetrates into the graphite sheet,   e. attaching the grip of the adaptor to the pipe such that the grip embraces the pipe, further;   f. providing the attachment with appropriate thermal contact,   g. coupling the pipe to heat utilization system,   h. circulating a heat transfer medium through the pipe, the pipe thereby extracting the collected solar heat and transferring it to the heat utilization system.   i. coupling the pipe to a heat utilizing system.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to understand the invention and to see how it may be implemented in practice, a plurality of embodiments is adapted to now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which 
         FIG. 1   a  is an isometric exploded view of the solar energy collecting assembly according to an embodiment comprising a heat transfer medium pipe having slit-like ports and a graphite sheet having a crenulated edge; 
         FIG. 1   b  is an isometric general view of the solar energy collecting assembly according to the embodiment comprising a heat transfer medium pipe having slit-like ports and a graphite sheet having a crenulated edge; 
         FIG. 2   a  is a cross-section view of the solar energy collecting assembly according to the embodiment comprising a graphite sheet and a heat transfer medium pipe having invaginations located along a heat transfer medium pipe; 
         FIG. 2   b  is an isometric general view of the solar energy collecting assembly according to the embodiment comprising a graphite sheet and a heat transfer medium pipe having invaginations located along a heat transfer medium pipe; 
         FIG. 3   a  is a cross-section view of the solar energy collecting assembly according to the embodiment comprising a heat transfer medium pipe, a graphite sheet, and an adaptor disposed between a graphite sheet and a heat transfer medium pipe and having pins penetrating into a graphite sheet; 
         FIG. 3   b  is an isometric general view of the solar energy collecting assembly according to the embodiment comprising a heat transfer medium pipe, a graphite sheet, and an adaptor disposed between a graphite sheet and a heat transfer medium pipe and having pins penetrating into a graphite sheet. 
         FIG. 4   a  is a cross-section view of the solar energy collecting assembly according to an embodiment comprising a heat transfer medium pipe, a graphite sheet, and an adaptor disposed between a graphite sheet and a heat transfer medium pipe and having a slot adapted to hold the graphite sheet; 
         FIG. 4   b  is an isometric general view of the solar energy collecting assembly according to the embodiment comprising a heat transfer medium pipe, a graphite sheet, and an adaptor disposed between a graphite sheet and a heat transfer medium pipe and having a slot adapted to hold the graphite sheet; 
         FIG. 5   a  is a schematic view of the solar energy collecting assembly according to the embodiment comprising metal and plastic plates; 
         FIG. 5   b  is a schematic view of the solar energy collecting assembly according to the embodiment comprising metal and plastic plates with graphite spacers between them. 
         FIG. 6   a  is an isometric exploded view of the solar energy collecting assembly according to an embodiment comprising a heat transfer medium pipe having slit-like ports and a plane shaped solar collector having a crenulated input/output nipples; 
         FIG. 6   b  is a schematic view of a plane shaped solar collector formed by two metal plates spaced by graphite spaces; 
         FIG. 6   c  is a cross-section view of a plane shaped solar collector formed by two metal plates spaced by graphite spaces; and 
         FIG. 6   d  is a schematic view of a plane shaped solar collector formed by two graphite sheets with grooves adapted to form heat transfer agent passages. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide a solar energy collecting assembly. 
     The term ‘Heat transfer medium’ refers hereinafter in a non-limiting manner to cooling fluids, for example water, including water with additives, like corrosion inhibitors and antifreezes, and mineral oils, silicone oils, fluorocarbon oil, and refrigerants as well as gases, for example inert gases, nitrogen, carbon dioxide, sulfur hexafluoride. 
     The term “crenulated edge” refers to a particular embodiment, but can be used interchangeably with any conveniently shaped edge. 
     The term “plane housing” hereinafter refers to a housing for enclosing fluid channels formed essentially by two parallel plates as exemplified in a non limiting manner, by  FIGS. 5   a  and  5   b.    
     The suggested technical solution can be used for heat exchange between heat transfer medium and air surrounding graphite sheets. Heat transfer direction can be both from heat transfer medium to air and from in an opposite direction. Thus this device can be used both as a heater and as a cooler. 
     Reference is now made to  FIG. 1   a  and  FIG. 1   b , of one embodiment of the invention, schematically illustrating a solar energy collecting assembly comprising a heat transfer medium pipe  10 , having slit-like ports  12  and a graphite sheet  20  having a crenulated edge with vanes  22 . After assembly a commissure is provided, and the assembly is then sealed by caulking  30 . 
     Reference is now made to  FIG. 2   a  and  FIG. 2   b , of another possible embodiment of the invention, schematically illustrating a collecting assembly comprising a graphite sheet  20  and a heat transfer medium pipe  10  having invaginations  40  disposed along a heat transfer medium pipe. 
     Reference is now made to  FIG. 3   a  and  FIG. 3   b , of yet another embodiment of the invention, schematically illustrating a solar energy collecting assembly comprising a heat transfer medium pipe  10 , a graphite sheet  20 , and an adaptor  50  between them. The adaptor is furnished with pins  52  that penetrate into the graphite sheet  20  for providing enhanced heat transfer. The graphite sheet  20  is bolted down by a plate  54 . The bolts are not shown in the Figs. 
     Reference is now made to  FIG. 4   a  and  FIG. 4   b , of a further embodiment of the invention, schematically illustrating a solar energy collecting assembly comprising heat transfer medium pipe  10 , a graphite sheet  20 , and an adaptor  60  between them. The adaptor is furnished with a slot  62  adapted to hold the graphite sheet  20 . 
     Reference is now made to  FIG. 5   a  and  FIG. 5   b , of further embodiments of the invention, schematically illustrating a solar energy collecting assembly comprising metal and plastic plates  72  and  74 , respectively. Solar rays  70  are incident on the metal plate  72  and heat the heat transfer agent flowing in the grooves  76 . In accordance with the embodiment of the invention shown in  FIG. 5   a , the metal plate  72  is directly attached to the plastic plate  74 . Channels for heat transfer agent flowing are formed by the grooves  76  and metal plate  72 . An inner surface  78  of the grooves  76  is sufficiently rough to provide turbulence in heat transfer agent flow. In the embodiment of the invention shown in  FIG. 5   b , the channels  82  for heat transfer agent flow are formed by means of graphite spacers  80 . The inner plastic surface  78  is similar sufficiently rough to provide turbulence in heat transfer agent flow. 
     Reference is now made to  FIG. 6   a , of further embodiment of the invention, schematically illustrating a solar energy collecting assembly comprising a heat transfer medium pipe  10 , having slit-like ports  12  and a plane housing  90  having crenulated input/output nipples. 
     Reference is now made to  FIG. 6   b - 6   c , of further embodiment of the invention schematically illustrating a plane housing formed  90  formed by two heat conducting metal plates  72  spaced by graphite spacers  80 . Graphite spacers  80  are adapted to provide passages for heat transfer agent. Each passage is furnished with input and output ports  92 . Dashed lines indicate the heat transfer agent passages. 
     Reference is now made to  FIG. 6   d , of further embodiment of the invention schematically illustrating a plane housing formed  90  formed by two graphite sheets having special grooves adapted to provide passages for heat transfer agent. Each passage is furnished with input and output ports  92 . Dashed lines indicate the heat transfer agent passages. 
     In accordance with the embodiment of the invention, the heat transfer medium pipe  10  coupled to a heat utilizing system furnished with the slit-like ports  12 . Solar radiation absorbed by the graphite sheets  20  is converted into heat. Solar heat is transferred along the crystalline surface of the graphite sheets  20  to a heat transfer medium circulating in the heat transfer medium pipe  10 . 
     As can be seen in  FIG. 1   a  and  1   b , the graphite sheet  20  has a plurality of vanes  22  at its edge corresponding to the slit-like ports  12 . The vanes  22  are housed in the slit-like ports  12  and sealed by caulking  30 . 
     The vanes  22  protrude into the heat transfer medium pipe  10  thereby enhancing the heat transfer rate for the following reasons. Firstly, an area of contact is increased because the heat transfer medium laves the protruded vanes  22 . Secondly, the protruberance of the vane  22  into the heat transfer medium pipe  10  results in turbulent flow in the heat transfer medium pipe  10 . As is well known, turbulence increases heat exchange efficiency between heated surfaces and the heat transfer medium. 
     Referring to  FIGS. 2   a  and  2   b  in accordance with this embodiment of the invention, the heat transfer medium pipe is furnished with the elongated invaginations  40  located along the heat transfer medium pipe  10 . Solar heat converted from solar radiation by the graphite sheets  20  is transferred from them to the heat transfer medium circulating in the heat transfer medium pipe  10 . The invaginations are adapted to hold the graphite sheets  20 . Disposing the graphite sheets  20  into the invaginations  40  extends the area of thermal contact between the graphite sheets  20  and the heat transfer medium pipe  10 . This is a novel advance on the prior art because the invaginations  40  additionally embrace a part of the side surface of the graphite sheets  20  that in turn enhances an area of thermal contact and heat transfer velocity. 
     In accordance with a further embodiment of the invention ( FIGS. 3   a  and  3   b ), the adaptor  50  is disposed between the graphite sheet  20  and the heat transfer medium pipe  10 . The adaptor  50  is made of a material with high thermal conductivity and thermally joins the graphite sheet  20  to the heat transfer medium pipe  10 . Additionally, the adaptor  50  is furnished with the plurality of the pins  52 . The pins  52  protrude into the graphite sheet to provide enhanced heat transfer from the graphite sheet  20  to the heat transfer medium pipe  10 . 
     Solar heat converted from solar radiation by the graphite sheets  20  is transferred from the sheets  20  to the heat transfer medium circulating in the heat transfer medium pipe  10 . The pins  52  penetrate into the graphite sheets  20  and extract converted solar heat. Since the pins are in thermal contact with the adaptor  50 , the pins  52  transfer heat to the adaptor  50  and further to the heat transfer medium in the pipe  10 . Increase of heat transfer results from extracting converted heat from the whole thickness of the graphite sheets  20 . 
     In accordance with the embodiment of the invention shown in  FIGS. 4   a  and  4   b  the adaptor  60  is disposed between the graphite sheet  20  and the heat transfer medium pipe  10 . The adaptor  60  is made of a material with high thermal conductivity and thermally joins the graphite sheet  20  to the heat transfer medium pipe  10 . Additionally, the adaptor  60  is furnished with the slot  62  adapted to hold the graphite sheet  20 . An arrangement of the slot  62  is adapted to be in thermal contact with an end surface of the graphite sheet  20 . Heat collected by the graphite sheet  20  transfers to the heat transfer medium flowing in the pipe  10 . The thermal contact of the end surface of the graphite sheet  20  with the adaptor  60  and embracing a part of side surface of the graphite sheet  20  provides maximum effective heat transfer. 
     In accordance with the embodiment of the invention shown in  FIG. 5   a  solar light heats the metal plate  72 . This plate  72  has preferably light gauge (about 0.1 mm) and is coated with coatings absorbing solar rays. Heat absorbed by the plate  72  transfers to the heat transfer agent flowing in the channels formed by the grooves  76  and the plate  72 . The inner surface  78  of the grooves  76  has sufficient roughness to create turbulence in heat transfer agent flow. 
     In accordance with the embodiment of the invention shown in  FIG. 5   b  the graphite spacers  80  are introduced between the metal plate  72  and the plastic plate  74 . The graphite spacers  80  form channels  82  for heat transfer agent flow. The inner surface  76  of the plastic plate  74  is rough. Turbulence provided by roughness of the plastic surface  76  enhances efficiency of heat transfer. The embodiments of the invention shown in  FIGS. 5   a  and  5   b  are very cost effective due to high efficiency of heat transfer and low cost. 
     Thus, the proposed technical solutions enable efficient heat transfer from the graphite sheet  20  to the heat transfer medium flowing in the pipe  10  by conductivity due to enhancement of the thermal contact area between them. 
     Efficient means and methods of extraction of converted heat from solar collecting devices, as exemplified above, has therefore fulfilled a long felt need. 
     It will be appreciated that the above described methods may be varied in many ways including, changing the order of steps, and/or performing a plurality of steps concurrently. 
     It should also be appreciated that the above described description of devices and methods are to be interpreted as including apparatus for carrying out the methods, and methods of using the devices, of any type as well known to a person of ordinary skill, and which need not be described in detail herein for enabling a person of ordinary skill to practice the invention, since such a person is well versed in engineering and thermodynamics. 
     For the main embodiments of the invention, the particular selection of type and model is not critical, though where specifically identified, this may be relevant. The present invention has been described using detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. No limitation, in general, or by way of words such as “may”, “should”, “preferably”, “must”, or other term denoting a degree of importance or motivation, should be considered as a limitation on the scope of the claims or their equivalents unless expressly present in such claim as a literal limitation on its scope. It should be understood that features and steps described with respect to one embodiment may be used with other embodiments and that not all embodiments of the invention have all of the features and/or steps shown in a particular figure or described with respect to one of the embodiments. That is, the disclosure should be considered complete from combinatorial point of view, with each embodiment of each element considered disclosed in conjunction with each other embodiment of each element (and indeed in various combinations of compatible implementations of variations in the same element). Variations of embodiments described will occur to persons of the art. Furthermore, the terms “comprise,” “include,” “have” and their conjugates, shall mean, when used in the claims, “including but not necessarily limited to.” Each element present in the claims in the singular shall mean one or more element as claimed, and when an option is provided for one or more of a group, it shall be interpreted to mean that the claim requires only one member selected from the various options, and shall not require one of each option. The abstract shall not be interpreted as limiting on the scope of the application or claims. 
     It is noted that some of the above described embodiments may describe the best mode contemplated by the inventors and therefore may include structure, acts or details of structures and acts that may not be essential to the invention and which are described as examples. Structure and acts described herein are replaceable by equivalents which perform the same function, even if the structure or acts are different, as known in the art. Therefore, the scope of the invention is limited only by the elements and limitations as used in the claims.