Patent Publication Number: US-11644222-B2

Title: Electromagnetic cooling and heating

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/879,097 filed Jul. 26, 2019, which is hereby incorporated herein by reference, in its entirety. 
     TECHNICAL FIELD 
     The invention relates generally to cooling and heating, and more particularly, to a system for electromagnetic cooling and heating. 
     BACKGROUND 
     In currently available cooling systems, as in refrigerators or AC units, a refrigerant is usually circulated with an electric pump, where the refrigerant takes heat from an enclosed area and releases it to the outside. In such an operation process, substantial electric power is consumed. When heat flow is reversed, the resultant system becomes a heat pump that heats a designated area, also requiring substantial electric power as well. 
     Therefore, what is needed is an apparatus and method for cooling and heating without external power sources. 
     SUMMARY 
     In the proposed device, the cooling process is all passive and no electric power is needed to cool the area in an enclosed volume. 
     In accordance with principles of the invention, thermal energy is transferred from a hot region to a cold region via an electromagnetic device. For example, the cold temperature outside earth&#39;s atmosphere (“space”) can be utilized to pump heat from an enclosed volume on earth to the outer space. A relatively simple system of low cost at mass production can be made to do this. The system can be used for air-conditioning (AC) systems. With a proper design, it is possible to facilitate fast cooling analogous to rapid heating of food stuff achieved by a conventional microwave oven. 
     It is also possible to produce efficient heating by reversing the heat flow in the opposite direction compared to that in the cooling system. 
     An antenna is a device that takes power from an electromagnetic wave as a receiver while it can also be used as a transmitter of electromagnetic power. Depending on its surrounding area, an antenna can take thermal electromagnetic power at an infrared spectrum as well. The amount of thermal power radiated by an object is characterized by a black-body radiation temperature. When a high-gain antenna, such as a reflector antenna, points to the ground, the amount of power collected by the antenna is similar to that from a black body of the ground temperature. However, when the main beam is directed to the zenith of the sky, the power received by the antenna will be much smaller due to the fact that the radiation temperature of the open sky is substantially low, usually less than the freezing point of water. 
     A transmission line connects two antenna systems to transport electromagnetic power from a high-temperature area to a low-temperature region for electromagnetic cooling. In the antenna and transmission-line designs, there are two required conditions to make these antennas effective in electromagnetic cooling: 
     The transmission line has to be designed to reduce any added thermal power while electromagnetic waves propagate within the waveguide transmission line connecting two antennas at the ends of the transmission line. Metallic surfaces are convenient for antenna and transmission-line designs. However, metallic surfaces substantially add thermal power to the antennas and transmission line. Thus, it is recommended to have all dielectric antennas and transmission lines at frequencies of thermal agitation. 
     An antenna inside a region where heat is to be pumped to be cooled must have a broad beam to collect most of the electromagnetic power regardless of the incident angle, but an antenna outside the region must be highly directional or of high gain so that the antenna beam is pointed to a location of low effective temperature, such as the zenith of the sky. 
     Since the electromagnetic fields need to be confined within the dielectric transmission line, a cladding will reduce interaction with thermal agitation from the surrounding area. Also, a circular shape is easier to fabricate, as in optical fibers. The antenna at the tip of the transmission line can be tapered so that the electromagnetic power leaks out as the wave travels to the end without much reflection over a wide frequency range of the infrared spectrum. 
     The above system may also be used for heating when the chamber is colder than the region in the outside. In other words, the high-gain antenna should be pointed to the region where heat is coming from, such as the sun, and the low-gain antenna should be pointed to the region to be heated. Otherwise, the operation principles for cooling and heating remain the same. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a schematic diagram exemplifying one embodiment for a chamber to be cooled and a chamber from which heat is dissipated, antennas in the two chambers that are connected by a transmission line, and a dielectric rod with a core and cladding region for the transmission line, in accordance with principles of one embodiment of the invention; 
         FIG.  2    is a schematic diagram exemplifying an alternative embodiment to that depicted by  FIG.  1   , wherein more than one pair of antennas and transmission line are employed in accordance with principles of the present invention; 
         FIG.  3    is a schematic diagram exemplifying an alternative embodiment to that depicted by  FIG.  1   , wherein the transmission line is removed in accordance with principles of the present invention; 
         FIG.  4    is a schematic diagram exemplifying an alternative embodiment to that depicted by  FIG.  2   , wherein the transmission lines are removed in accordance with principles of the present invention; 
         FIG.  5    is a schematic diagram exemplifying one embodiment for a dielectric rod above a conducting plate with an aperture under the dielectric rod to be used for the dielectric antennas in the electromagnetic cooling and heating devices in accordance with principles of the present invention; and 
         FIG.  6    is a schematic diagram exemplifying an alternative embodiment of use depicted by  FIG.  5   , wherein a conical dielectric is attached above the cylindrical rod in accordance with principles of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. 
       FIG.  1    depicts a system  100  for electromagnetic cooling including a chamber  101  and a chamber  102 , that are connected by a transmission line  103 , the ends of which are connected to impedance-matched an antenna  104  in chamber  101  and an antenna  105  in the chamber  102 . Here, chamber  101  is a region to be cooled and chamber  102  is a region where the effective temperature is small and to which heat is pumped. At the frequency spectrum of thermal excitation, a dielectric transmission line over a metallic waveguide is preferred to reduce added thermal power from conduction losses on the metallic surfaces. Since the electromagnetic fields need to be confined while a wave propagates within the dielectric transmission line, a high dielectric constant of the dielectric transmission line  103  can be used to reduce interference from its surrounding area while a wave propagates within the waveguide structure of the dielectric transmission line  103 . To further reduce the interaction with thermal agitation external to the waveguide, a cladding layer is preferably added over a core layer where the dielectric constant of the cladding is slightly less than that of the core. Also, a circular shape is preferred for easy fabrication, such as optical fibers, though other cross-sectional shapes are acceptable. 
     In the operation of system  100 , antenna  104  in chamber  101  has a broad beam so that most of the thermal radiation within chamber  101  is collected by antenna  104  and transmitted to transmission line  103 . The transmitted power propagates along transmission line  103  and reaches antenna  105  in chamber  102 , where antenna  105  radiates the accepted power from transmission line  103  to a cool region of chamber  102 . Both antennas  103  and  104  are preferred to have a relatively large bandwidth to cover most thermal radiation at the temperature of interest. Antennas  104  and  105  are preferably dielectric antennas to increase radiation efficiencies. 
       FIG.  2    depicts a system  200  with a number of pairs of the antennas and transmission line that are described in system  100 . A set of antennas  204  in a chamber  201  to be cooled have a broad beam and most of the thermal radiation energy in chamber  201  is captured by antennas  204  and transmitted to a set of transmission lines  203 . The transmitted power propagates along the set of transmission lines  203  and reaches a set of antennas  205  in a chamber  202  of cold region where heat energy is to be absorbed. There will be net heat flow from chamber  201  to chamber  202 , and enclosed chamber  201  will be cooled as long as chamber  202  is colder than chamber  201 . The colder chamber  202  is, the faster chamber  201  is cooled. Also, a circular shape is preferred for easy fabrication, such as optical fibers, though other cross-sectional shapes are acceptable. 
       FIG.  3    depicts a system  300  and includes a chamber  301  to be cooled, an antenna  302  inside chamber  301 , and an antenna  303  outside chamber  301 . Antennas  302  and  303  are connected to each other by an aperture  304  on the wall of chamber  301 . 
     In the operation of system  300 , antenna  302  inside chamber  301  has a broad beam so that most of the thermal radiation within chamber  301  is collected by antenna  302  and transmitted to antenna  303  via aperture  304  on the wall of chamber  301 . Antenna  303  radiates the accepted power from antenna  302  to a cold region  305  such as the outer space. Antenna  303  preferably has a high gain for the radiated power to be focused to region  305 . High-gain antennas include reflector antennas, horn antennas, and lens antennas as well as well-designed dielectric antennas. To increase radiation efficiencies, dielectric antennas can be used. Both antennas  302  and  303  are preferred to have a relatively large bandwidth to cover most radiation at the temperature of interest. 
       FIG.  4    depicts a system  400  with a number of pairs of antennas and aperture as described in system  300 . A set of antennas  402  inside a chamber  401  to be cooled have a broad beam so that most of the thermal radiation energy in chamber  401  is captured by antennas  402  and transmitted to a set of antennas  403  through apertures  404  on the wall of chamber  401 . The set of antennas  403  radiate the accepted power from antennas  402  to a cold region  405 , such as the zenith of the sky. In order to focus the electromagnetic beam to a particular location of a cold area  405  where heat energy is absorbed, antennas  403  need to be of high gain. High-gain antennas include reflector antennas, horn antennas, and lens antennas. Properly designed dielectric antennas can be used to increase the radiation efficiency. There will be heat flow from region  405  to chamber  401 . However, as long as region  405  is colder than chamber  401 , the enclosed chamber  401  will be cooled. The colder region  405  is, the faster chamber  401  will be cooled. 
       FIG.  5    depicts a dielectric antenna  500  and includes a circular cylinder of dielectric rod  501  and a coupling aperture  502  on a conducting plate  503 . The antenna is used to transmit electromagnetic power as a transmitter while it is also used to receive radiation power as a receiver. 
     In the operation of system  500 , electromagnetic power is coupled from below conducting plate  503  through coupling aperture  502  to form electromagnetic excitation within antenna  501  that radiates electromagnetic power in a focused beam. With a proper design, the focused beam is in the direction normal to conducting plate  503 . The height of the dielectric antenna  501  is varied to change the antenna gain that shows the beam focus of radiated power. A circular cylinder of dielectric rod  501  is preferred for easy fabrication though other shapes are acceptable. 
       FIG.  6    depicts a dielectric antenna  600  of  FIG.  5    and includes a dielectric rod  601 , a conical dielectric  602  attached to dielectric  601 , and a coupling aperture  603  on a conducting plate  604 . The operation principle of antenna  600  is the same as that of antenna  500  except that the conical dielectric  602  increases the frequency bandwidth as well as the gain. A circular cylinder of dielectric road and a circular dielectric cone are preferred for easy fabrication though other shapes are acceptable. 
     The above devices may also be used for heating when the temperature gradient of the two regions is switched. In other words, the high-gain antenna is pointed to the region where heat is coming from, and the low-gain antenna is connected to the region to be heated. Otherwise, the operation principles remain the same. 
     Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.