Abstract:
A fluidkinetic energy converter includes a passageway-filled enclosure. Turbines are mounted in the passageways and fluid flow may be concentrated on subparts of the turbines by inner fluid flow deflectors or dividers. The energy converter enclosure can include dividers at both inlets and outlets in order to be adaptable for either river or tidal environments. Notably, apart from the turbines and energy generating components, the enclosure may be implemented such as to have no moving parts, thereby reducing complexity, cost, and weight.

Description:
BACKGROUND 
       [0001]    The present application relates generally to the field of fluid-based energy conversion and more specifically to fluidkinetic energy conversion in both uni- and bi-directional currents. 
         [0002]    Historically, conventional methods of converting water flow into useable energy have been done through large dams and systems of generators. While the electricity generated from these sources is reliable, altering the natural flow of rivers has an extremely negative impact on the environment. Although devices have been used in converting flowing water into useable energy for centuries, there has been a recent push for more environmentally friendly solutions to produce power and provide energy. Much progress has been made in recent years improving upon designs that convert kinetic energy from tides and rivers into an energy source available to the public. 
         [0003]    These fluidkinetic devices have significant advantages over solar and wind powered devices. Tides and rivers offer a much more reliable, predictable and consistent source of renewable energy, if captured correctly. Previous designs and proposals are far from ideal. Many tide conversion systems involve extreme environmental alterations. For example, the earliest tidal power station, the Rance Tidal Power Station, involves a half mile dam on the estuary restricting the natural flow of ocean and requiring a nine square mile tidal basin. 
         [0004]    Most fluidkinetic designs are also extremely complex and are expensive to build, transport, install, and maintain. The Francis turbine, for instance, is one of the most widely used designs in the world. However, its impressive efficiency comes from a rather complex design that includes moving turbine blades. Obviously, as moving parts are added, fluidkinetic energy conversion designs quickly become more complex and more expensive. 
         [0005]    Efforts have recently been made to provide devices that are able to efficiently extract electricity from the kinetic energy of naturally flowing bodies of water. These designs have allowed for smaller scale production and opened the possibility for many previously uneconomical generation sites. Many of these models are optimized for rivers and other inland water energy extraction, making them inefficient and/or unsuitable for use in tides. 
         [0006]    Designing a device that will work well in the ocean poses several unique challenges. Unlike inland energy capturing devices, an efficient and effective tidal device requires a bi-directional design of either the turbines, the generating system, or a combination of both. 
         [0007]    Several innovations have been made to allow for the capture of both the inbound and ebb flow of ocean tides. For example there have been designs where a conventional hydro turbine is mounted on a pivot on the floor of the ocean, or some other stationary object. Devices such as this are periodically rotated 180 degrees to face the changing direction of the current. While these types of devices are able to capture the majority of available flow, they are not yet commercially practical. Devices with more moving parts require more maintenance and will cost more to manufacture and operate than simple fixed devices. 
         [0008]    Therefore a need exists for a simple, reliable, economical solution for extracting kinetic energy from flowing bodies of water. The present invention provides a simple and cost-effective device for converting fluidkinetic energy into useable energy, such as electricity. 
       SUMMARY 
       [0009]    One embodiment of the present invention described below includes two turbines rotating in opposite directions and places them substantially in series in the same housing or enclosure. As shown, the turbines are offset, having one turbine positioned towards one end of the enclosure and one towards the opposite end. The enclosure inlets may include a fluid flow divider unit, or divider, which concentrates the fluid entering the device into two parallel passageways, each of which may have a width of approximately one third of the total width of the device. The divider unit may be connected to an internal wall which isolates the passageways. A number of configurations are possible for the divider. For example, in one embodiment, immediately in advance of the rear turbine, the internal wall may angle to the right to make room for the rear turbine. The wall may then continue and connect to the divider unit at the other end of the device. One advantage of some embodiments is that, because of the simplicity of the design, the rear half of the device may be a mirror image of the front half. This enables stationary bi-directional generation without additional moving parts or complex rotational devices or schemes. 
         [0010]    An electrical generating unit may be connected to the turbines in any number of ways. For example, a generator may be placed on top of the device to allow for easy installation and access for maintenance if necessary. To allow for both turbines to contribute to the rotation of the generating unit, gears, belts, or other rotational motion converters may be mounted to the shafts of the turbines that extrude from the top of the enclosure. This enables a lighter device and efficient gearing for the generator. 
         [0011]    In some embodiments, a cowl may be attached at one or both ends of the enclosure. The cowl, among other things, captures more fluid than the device would otherwise capture and increases the pressure and velocity of the fluid entering the device. The inclusion of the cowl may also enable higher device efficiency and more energy produced per unit. In some embodiments, a cowl may be attached at both ends to allow for the stationary unit to capture both the ebb and inward flows of the tide and have the benefit of a larger area of fluid captured by the device in either direction. 
         [0012]    The mounting apparatus for the device may preferably be very flexible to allow for installation in a broader range of energy or electricity producing sites. In some embodiments, the mounting apparatus may be grid like, allowing for the grid to be added on after initial installation or to be sized down after initial environmental evaluations. In some embodiments, the mounting apparatus may be configured so several grids are able to be connected together. This apparatus may also allow for smaller individual units to be part of a larger grid. This means that large, expensive single units are not required, but many smaller units may comprise a single grid that would otherwise be occupied by a large single unit. 
         [0013]    These smaller units allow, among other things, easy access to extract and repair or replace specific units without shutting down the entire production site. A monitoring system may also be installed to monitor each individual unit&#39;s power output allowing for easy diagnosis and maintenance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  shows the interior of an embodiment of the fluidkinetic energy conversion enclosure. 
           [0015]      FIG. 2  shows the fluid inlet of an embodiment of the fluidkinetic energy conversion enclosure. 
           [0016]      FIG. 3  shows the interior of another embodiment of the fluidkinetic energy conversion enclosure. 
           [0017]      FIG. 4  shows a skewed profile view of an embodiment of the fluidkinetic energy conversion enclosure. 
           [0018]      FIG. 5  shows a profile view of an embodiment of the fluidkinetic energy conversion enclosure complete with a generator casing. 
           [0019]      FIG. 6   a  shows a skewed view of an embodiment of an array of fluidkinetic energy conversion enclosures. 
           [0020]      FIG. 6   b  shows a skewed view of an embodiment of a two-dimensional array, or grid, of fluidkinetic conversion enclosures. 
       
    
    
       [0021]    Like reference numbers and designations in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0022]    In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that various changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. 
         [0023]      FIG. 1  shows one embodiment of the fluidkinetic energy converter. Fluidkinetic energy converter apparatus enclosure  100 , is shown from above. This view shows the enclosure subdivided into two passageways  103  and  104 , each passageway creating fluid communication between fluid inlet  130  and fluid outlet  140 . As is demonstrated in this figure by way of multiple parallel arrows approaching inlet  130 , this embodiment is designed to accept fluid at inlet  130 . As the fluid enters inlet  130 , it encounters an interior structure or fluid flow divider  105 . The purpose of the divider  105  at the inlet is to focus and concentrate the fluid flow into a given flow path in a subsection of the passageway. This can be accomplished by dividers of numerous variety of shapes and sizes, one of which may be as shown in this embodiment as an elongated isosceles triangle shape for divider  105 . 
         [0024]    Looking first at the fluid flow paths in passageway  103  of  FIG. 1 , the fluid, after being redirected by divider  105 , comes into contact with the working portion  101   a  of turbine  101 . It can be seen that one of the purposes of divider  105  is to divert fluid away from the returning portion  101   b  of turbine  101  that, if impacted by the fluid, would hinder its ability to freely rotate about its axis of rotation. As the fluid comes into contact with turbine  101  in this configuration, it induces rotation in a counter-clockwise orientation. Were diverter  105  not in place, the fluid flow would impact not only the working portion  101   a  of turbine  101 , but it would also impact the returning portion  101   b . The fluid in contact with the working portion  101   a  of  101  would attempt to induce counter-clockwise rotation while the fluid in contact with the returning portion  101   b  of  101  would attempt to induce clockwise rotation. The combined forces would largely cancel each other out and lead to a highly inefficient turbine arrangement. Therefore, the divider  105  may be preferentially positioned to be such as to focus the fluid flow on a working portion  101   a  of turbine  101 . Generally speaking, the minimum width of the passageways  103  and  104  and the radius of the respective turbines  101  and  102  may be optimized to accommodate the anticipated fluid flow. 
         [0025]    Returning to  FIG. 1 , after fluid passes by turbine  101 , it continues through passageway  103  and exits the enclosure at fluid outlet  140 . Fluid flow through passageway  104  works in the same manner as discussed for passageway  103 . One difference in passageway  104  is that turbine  102  may be offset and located further back from the inlet  130 . In this embodiment, this offset arrangement allows for two turbines,  101  and  102 , to be aligned substantially in series, meaning that they are in the fluid flow path in a sequential or one-after-the-other, as opposed to parallel, arrangement, and therefore decrease the overall width of the enclosure unit. Similar embodiments could potentially allow for more than two turbines being arranged in series all while maintaining a relatively modest overall enclosure width. Likewise, a vertical, or top-and-bottom, and other arrangements of turbines  101  and  102  can also be configured. Another difference with passageway  104  and turbine  102  as shown is that fluid passing through passageway  104  induces turbine  102  to rotate in the opposite rotational direction as turbine  101 . Of course, gearing, or other converters, can be implemented to drive a generator  110  (shown connected to turbines  101  and  102  by solid lines representing the wide range of connection possibilities) in a single direction of rotation.  FIG. 2  shows the embodiment of  FIG. 1  from in front of the fluid inlet  230 .  FIG. 2  also includes a cowl  220  which may be included on some embodiments to catch and redirect a larger volume of fluid into passageways  203  and  204  and through the enclosure  200 . Other fluid capture devices may also be used. Gears  211  and  212  may be attached to the rotational axes of turbines  101  and  102  (not shown). Other motion translators may also be used. Generator attachment  215  may also be located adjacent to gears  211  and  212 . As fluid induces rotation of turbines  101  and  102 , gears  211  and  212  also rotate. The gears  211  and  212  may be attached to a generator  210  (shown connected to gears  211  and  212  through solid lines representing the wide range of connection possibilities) that translates the gear rotation into electricity or other useful work output. 
         [0026]      FIG. 3  is another embodiment of the fluidkinetic energy conversion enclosure  300 . In this embodiment, the passageways  303  and  304  are configured with dividers  305  and  306  to enable the turbines to accept bi-directional fluid flow. In this embodiment, either end of enclosure  300  serves as an inlet or outlet. Each opening  330  and  340  may be configured to divert and focus fluid onto working portions of turbines  301  and  302 . This embodiment may be advantageously located, for instance, in a tidal environment where the currents ebb and flow. 
         [0027]    For example, as current enters opening  330 , it meets divider  305  and is focused into passageways  303  and  304 , respectively. As shown, the fluid in passageway  303  induces counter-clockwise rotation of turbine  301 , and then continues through passageway  303  eventually exiting the enclosure through opening  340 . Also as shown, the fluid in passageway  304  travels through the passageway and induces clockwise rotation of turbine  302  before exiting the enclosure at opening  340 . Then, when the tide reverses direction, fluid enters the enclosure through opening  340 , meets divider  306 , and is focused into passageways  303  and  304 . For this flow direction, the fluid in passageway  304  induces counter-clockwise rotation of the turbine  302  and then continues through the passageway  304  and exits the enclosure through opening  330 . The fluid continues in passageway  303 , travels the length of the passageway, induces clockwise rotation of turbine  301  and then exits the enclosure at opening  330 . In a tidal environment, the constant ebb and flow of the ocean currents would constantly induce turbine rotation that would be translated into energy, such as electricity, through a generator unit. Again, suitable gearing or other motion translators can be implemented to drive an electrical generator or other output. 
         [0028]      FIG. 4  shows a skewed profile view of the tidal embodiment of  FIG. 3 . As in the preceding embodiment, this one includes cowl  420 . In a tidal operation it may be advantageous to include a second cowl  421 . The current embodiment may implement gears  411  and  412  or other similar rotational motor converter in much the same fashion as the embodiment in  FIG. 2 . Also seen in  FIG. 4  are the generator attachment  415  and the divider  405 . 
         [0029]      FIG. 5  shows a profile view of a dual cowl,  520  and  521 , embodiment. This figure also shows the addition of a generator cover  525  which encloses the motion translators (e.g., gears  411  and  412 ) and the generator unit. Other protective covers may also be implemented. 
         [0030]      FIG. 6   a  shows a skewed profile view of an array of generator apparatuses,  600   a ,  600   b,    600   c,  . . .  600   n,  according to one possible embodiment. As understood by those of ordinary skill in the art, other one, two, and three dimensional array or grid arrangements, such as the grid in  FIG. 6   b , are also possible. 
         [0031]      FIG. 6   b  shows a possible two dimensional or grid embodiment created by stacking multiple one dimensional arrays,  600   a - n,x ,  600   a - n,y , and  600   a - n,z , of generator apparatuses upon each other. 
         [0032]    Although this invention has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art, including embodiments that do not provide all of the features and advantages set forth herein, are also within the scope of this invention. Accordingly, the scope of the present invention is defined only by reference to the appended claims and equivalents thereof.