Abstract:
An underground heat transferring method and system is disclosed. The system includes a water-blocking heat-exchanging outer wall defining an enclosure and an insulated tube located inside the enclosure. The insulated tube defines a perforated portion at the bottom. Multiple heat exchanging particles are disposed between the outer wall and the insulated tube. The system also includes an inlet that is configured for receiving a working fluid and directing the working fluid to flow through the heat exchanging particles towards the bottom of the enclosure. A pump located inside the insulated tube is configured for pumping the working fluid collected at the bottom of the insulated tube. An exhalant siphon fluidly connected to the pump inside the insulated tube is configured for delivering the working fluid out of the underground heat transferring system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No. 61/720,601, filed Oct. 31, 2012. Said U.S. Provisional Application Ser. No. 61/720,601 is hereby incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The disclosure generally relates to the field of energy harvesting systems, and particularly to a method and system for harvesting ground energy. 
       BACKGROUND 
       [0003]    A ground-coupled heat exchanger is an underground heat exchanger that can capture heat from and/or dissipate heat to the ground. Technologies such as buried pipes/tubes are commonly utilized to facilitate the heat exchange. However, traditional buried pipes/tubes technology is poorly efficient in energy collection and highly demanding in land occupation, therefore it is hard to achieve wide-spread application. 
       SUMMARY 
       [0004]    The present disclosure is directed to an underground heat transferring system. The system includes a water-blocking heat-exchanging outer wall defining an enclosure and an insulated tube located inside the enclosure. The insulated tube defines a perforated portion at the bottom. Multiple heat exchanging particles are disposed between the outer wall and the insulated tube. The system also includes an inlet that is configured for receiving a working fluid and directing the working fluid to flow through the heat exchanging particles towards the bottom of the enclosure. A pump located inside the insulated tube is configured for pumping the working fluid collected at the bottom of the insulated tube. An exhalant siphon fluidly connected to the pump inside the insulated tube is configured for delivering the working fluid out of the underground heat transferring system. 
         [0005]    A further embodiment of the present disclosure is also directed to a heat transferring method. The method includes: directing a working fluid to flow through a plurality of heat exchanging particles disposed between a water-blocking heat-exchanging outer wall and an insulated inner tube; collecting the working fluid at the bottom of the inner tube; and pumping the collected working fluid through an exhalant siphon to deliver the working fluid. 
         [0006]    An additional embodiment of the present disclosure is directed to an underground heat transferring method. The method includes: a) directing a working fluid to flow through a plurality of heat exchanging particles disposed between a water-blocking heat-exchanging outer wall and an insulated inner tube; b) collecting the working fluid at the bottom of the inner tube; c) pumping the collected working fluid through an exhalant siphon located inside the insulated tube to deliver the working fluid to a heat consuming device; and d) receiving the working fluid returned from the heat consuming device and repeating step a). 
         [0007]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the present disclosure. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate subject matter of the disclosure. Together, the descriptions and the drawings serve to explain the principles of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The numerous advantages of the disclosure may be better understood by those skilled in the art by reference to the accompanying figures in which: 
           [0009]      FIG. 1  is a side elevation cross-sectional view of the heat exchanging and accumulating single well system for ground energy collection in accordance with the present disclosure; 
           [0010]      FIG. 2  is another side elevation cross-sectional view of the heat exchanging and accumulating single well system of  FIG. 1 ; 
           [0011]      FIG. 3  is a top view of the heat exchanging and accumulating particles; 
           [0012]      FIG. 4  is an illustration depicting the insulated tube and its perforated portion; 
           [0013]      FIG. 5  is an illustration depicting the heat exchanging and accumulating particles; 
           [0014]      FIG. 6  is an illustration depicting the heat exchanging and accumulating particles arranged in a different manner; 
           [0015]      FIG. 7  is an illustration depicting the heat exchanging and accumulating particles arranged in yet a different manner; and 
           [0016]      FIG. 8  is a method flow diagram illustrating a heat transferring method in accordance with the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Reference will now be made in detail to the subject matter disclosed, which is illustrated in the accompanying drawings. 
         [0018]    The present disclosure is directed to a heat exchanging and accumulating single well system for ground energy collection (hereinafter referred to as “heat accumulating single well”). The heat accumulating single well in accordance with the present disclosure collects ground energy (i.e., heat) through cycle water to provide energy sources for heat pumps. With stable energy sources, heat pumps work to provide constant heating, cooling and domestic hot water to buildings. 
         [0019]    Referring generally to  FIGS. 1 through 4 , the heat exchanging and accumulating single well system  100  in accordance with the present disclosure is shown. The single well system  100  includes a water-blocking heat-exchanging outer wall  104  buried underground and an insulated tube  106  located inside the outer wall  104 . Heat exchanging and accumulating particles  102  are positioned between the water-blocking heat-exchanging wall  104  and the insulated tube  106 . As illustrated in  FIG. 2 , as water flows into the well downwards through the particles  102 , the particles  102  keep absorbing or releasing heat through the water-blocking heat-exchanging wall  104  until their temperature becomes the same as the ground source  112 . 
         [0020]    The water is then collected at the settling area  108  and eventually enters the bottom of the insulated tube  106  through its perforated portion. One or more water pumps  110  located near the bottom of the insulated tube  106  may then pump the cycle water up and out of the well  100 . The water pumped out of the well  100  may be delivered to power heat pumps or other heat consuming devices. And subsequently, the outflow from the heat pumps then flows back into the well  100 . After full contact with particles  102  for heat exchange, the water re-enters into the insulated tube  106  and repeats the cycle. 
         [0021]    It is contemplated that the water-blocking heat-exchanging wall  104  may be formed utilizing any material that is water resistant and suitable for heat transfer. Such materials may include, for example, fabric materials, plastic materials, metallic materials, or the like. It is also contemplated that while the water-blocking heat-exchanging material forms a circular wall as shown in  FIG. 3 , such a configuration is merely exemplary. The cross-section of the water-blocking heat-exchanging wall may be in various other shapes such as oval, square, rectangular or the like without departing from the spirit and scope of the present disclosure. 
         [0022]    It is further contemplated that the particles  102  utilized in accordance with the present disclosure may be arranged in various manners to provide different heat exchanging and accumulating properties. In one embodiment, the particles are substantially spherical particles having a predetermined diameter. The spherical shape forms gaps between the particles, and the predetermined diameter allows the gaps to be predictable. This allows the heat exchanging and accumulating properties of the overall system to be predictable as water moves through the particles. The ability to predict/calculate the heat exchanging and accumulating properties is appreciate in various situations, and it allows the system designer to adjust the diameter of the particles, which in turn adjusts the heat exchanging and accumulating properties of the overall system. 
         [0023]    For instance, as shown in  FIGS. 5 through 7 , particles having different diameters may be utilized to provide different heat exchanging and accumulating properties. The geometrical shape of the heat exchanging particles may be determined at least in part based on temperature of the ground energy source and/or the desired flow rate. For instance, larger particles may provide higher flow rate, which may be suitable if it is determined that the ground energy source provides a relatively higher temperature. On the other hand, smaller particles may provide lower flow rate, which may be suitable if it is determined that the ground energy source provides a relatively lower temperature. 
         [0024]    It is contemplated that the diameter of the particles may range between 1 cm and 10 cm, but may vary without departing from the spirit and scope of the present disclosure. It is also contemplated that the particles may include mostly rock, which is a naturally occurring solid aggregate of one or more minerals or mineraloids. However, other solid materials such as metallic materials or the like may also be utilized without departing from the spirit and scope of the present disclosure. Furthermore, while the particles  102  shown in the figures are generally spherical, other shapes and/or configurations may also be utilized. 
         [0025]    Now, referring specifically to  FIG. 1 , a particular embodiment of the single well system  100  in accordance with the present disclosure is shown. A well chamber  114  is utilized to provide fluid access into and out of the well. A sealant  116  seals the bottom of the well chamber  114  to prevent flow into the well other than through one or more predefined water inlets/pipes  118 . Water delivered into the well through such pipes  118  is allowed to flow into the well downwards through the particles  102 . It is contemplated that one or more deflectors  120  may be utilized to help evenly distribute the water flowing down the well, increasing heat exchange surfaces. 
         [0026]    As described above, the water flowing down the well is then collected at the settling area  108  and eventually enters the bottom of the insulated tube  106  through its perforated portion. One or more water pumps  110  located near the bottom of the insulated tube  106  then pump the water up through one or more exhalant siphons  122  and out of the well  100 . In this particular embodiment, the exhalant siphon  122  is positioned inside the insulated tube  106  until it enters the well chamber  114 . Positioning the exhalant siphon  122  inside the insulated tube  106  minimizes heat transfer that may occur on the exhalant siphon  122  as water is pumped out of the well  100 . 
         [0027]    In one embodiment, the outer diameter D is configured to be between 15 to 100 cm, the inner diameter d is configured to be between 10 to 30 cm. The water flow rate is determined based on the particular pump utilized for the system, which may vary based on specific needs and requirements. 
         [0028]    It is contemplated that the heat exchanging and accumulating single well system  100  in accordance with the present disclosure benefits from spacious heat exchange surface, continuously absorbing or releasing heat without any heat loss. The full contact of the particles  102  and the heat exchanging wall  104  greatly enhances the efficiency of heat exchanging and collection. It maximizes the utilization of ground energy and accumulates energy in a cyclic manner. Moreover, this system is applicable to various geological conditions. Therefore, it is a good solution for shallow-ground energy collection and a reliable technology to provide constant energy source for heat pumps. 
         [0029]      FIG. 8  is a method flow diagram illustrating a heat transferring method  800  in accordance with the present disclosure. In one embodiment, step  802  may direct a working fluid (e.g., water) to flow through a plurality of heat exchanging particles disposed between a water-blocking heat-exchanging outer wall and an insulated inner tube as described above. Step  804  may collect the working fluid at the bottom of the inner tube and step  806  may then pump the collected working fluid through an exhalant siphon and deliver the working fluid for energy consumption. The working fluid may be cycle back in step  808  and the method may repeat again from step  802 . 
         [0030]    The technology of heat accumulating single well in accordance with the present disclosure overcomes the disadvantages presented in the buried pipe technology and greatly enhances working efficiency in collecting the heat. The heat accumulating single well in accordance with the present disclosure increases the area of heat collection surface. It is not restricted to the heat exchange model used in traditional buried pipe where down-flow is to collect heat and up-flow is to release heat. In addition, it improves the efficiency of heat collection in comparison to traditional buried pipe where the contact of fillings with pipes and ground energy is not full. Furthermore, the ability to predict/calculate the heat exchanging and accumulating properties is appreciate in various situations, and it allows the system designer to adjust the diameter of the particles, which in turn adjusts the heat exchanging and accumulating properties of the overall system. 
         [0031]    Furthermore, it is contemplated that since the system in accordance with the present disclosure is a heat transfer system, it can be used alternatively for heating and/or cooling as is required. It is also understood that while the description above references water as the heat exchanging fluid, the fluid utilized in the system can be, without limitation, any working fluids include but are not limited to water, ethanol, methanol, acetone, as well as other engineered heat transfer fluids or any combination therein. Other working fluids having even better heat transfer characteristics may also be used without departing from the scope and spirit of the present disclosure. 
         [0032]    It is understood that the present disclosure is not limited to any underlying implementing technology. The present disclosure may be implemented using a variety of technologies without departing from the scope and spirit of the disclosure or without sacrificing all of its material advantages. 
         [0033]    It is believed that the present disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the disclosure or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.