Abstract:
A heat exchange apparatus that extends vertically along a longitudinal axis, that cools a liquid, including: a first delta positioned at a first point along the longitudinal axis, the first delta including: a first inlet conduit for inlet liquid flow, the first inlet conduit being in fluid communication with a first inlet main, and a first outlet conduit for outlet fluid flow, the first outlet conduit being in fluid communication with the first inlet conduit and a first outlet main, and a second delta positioned at a second point along the longitudinal axis above the first delta, the second delta including: a second inlet conduit for inlet liquid flow, the second inlet conduit being in fluid communication with a second inlet main, and a second outlet conduit for outlet fluid flow, the second outlet conduit being in fluid communication with the second inlet conduit and a second outlet main.

Description:
CLAIM FOR PRIORITY 
       [0001]    The present application is a nonprovisional application that claims priority to U.S. Provisional Patent Application Ser. No. 61/175,319, filed May 2, 2009, the disclosure of which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a natural draft cooling tower with heat exchangers of the dry-type, operating by natural draft and achieving the exchange of heat between two fluids such as atmospheric air, ordinarily, and another fluid, generally water. 
       BACKGROUND OF THE INVENTION 
       [0003]    Indirect dry cooling plants are typically tower arrangements or formations having multiple towers, utlilized to dissipate heat from industrial plants using large machinery, such as steam turbines, or industrial processes. For example, one type of cooling tower used in these plants is a chimney-type natural draft cooling tower which has a thin veil of concrete forming the side wall thereof. The chimney is open at the top and is supported above the ground by a plurality of legs, and the space between the lower edge of the veil and the ground defines the cooling air inlet for the heat exchange tower. 
         [0004]    In one design of a cooling tower, hot water from a condenser, is directed to the heat exchange units within the tower via a conduit, and the cooled water is directed back to the condenser via the conduit and a pump. As the name suggests, the condenser condenses and cools the exhaust exiting from a turbine and the cooled liquid is pumped to a boiler. 
         [0005]    In one example, traditional dry-type heat exchange batteries have finned tubes mounted vertically in pairs and are erected on the ground and concentric to an opening. The batteries are typically V-shaped, so that the heat exchange surface creates a toothed polygon, the teeth of which are directed toward the inside of the tower. 
         [0006]    A unit of traditional batteries of dry-type heat exchangers with finned tubes is placed horizontally or in slightly inclined fashion toward the bottom center of the tower, between the upper end of support columns and the upper end of the vertical batteries. The support columns are typically located in a single circular row near the opening inside the tower. Heat exchangers are mounted in pairs in V-shaped configurations, the peaks of which are directed upwards; each of the two units are connected by means of brackets. Because of the radial arrangement of the batteries situated above the air entry, an open space in the shape of a sector whose arc takes the shape of the periphery of the chimney exists between each pair of batteries. The spaces are typically sealed by plates to force the air to cross the batteries. The annular space between the wall and the extremity of the horizontal batteries is sealed off in analogous manner by plates. The same is done with triangular plates for the open space between the upper end of the vertical bottom and the inner end of the horizontal batteries. 
         [0007]    Each exchanger unit usually includes two beds. Each unit can be fed with water to be cooled separately or otherwise by means of the heater boxes in which the ends of the tubes of the heat exchange units are connected. Some beds are directly exposed to the cooling air while other beds receive air already partially heated in passing through the first beds. 
         [0008]    If the liquid to be cooled is to be circulated in series in each vertical battery and the horizontal battery to which it is affixed, and the cold air is first to meet the ascending current of hot water, the mounting described herein is carried out. 
         [0009]    The hot water is typically brought to the tower via a conduit, and deposited in a circular part forming a hot water collector. The collector is provided with a circulation pump, the collector is arranged at right angles to the vertical batteries. Next to the collector, a second circular collector is usually installed and is connected to the conduit to evacuate the cooled water. The orifice of the lower water box of a bed of batteries is connected to the hot water collector; by means of a pipe, the orifice of the upper water box of a bed of batteries is connected to orifice of the water box which is most inside the tower of the bed of batteries. By means of a pipe, the orifice of the water box most inside the tower of a bed of batteries is connected to the orifice of the upper water box of the bed of batteries. By suppressing the internal partition of water boxes of batteries which are most outside the tower, the beds of each horizontal battery are placed into communication with each other. Orifice of lower water box of a bed is connected to the cold water collector. 
         [0010]    Since water boxes of the batteries are common to both beds the water circulates automatically from the hot water entry towards the cold water evacuation piping using the beds successively, as soon as the siphon has been primed by a low output pump of greater manometric height than the circulation pump. 
         [0011]    The equipment may also have piping that is small in diameter, connected to the highest point of each battery. The pipes evacuate the gas contained in the batteries at the time of the filling of the batteries and the introduction of the gas at the time of the emptying of the batteries. This gas is either atmospheric air, possibly dried, or an inert gas such as nitrogen and its pressure will generally be greater than atmospheric. 
         [0012]    The aforementioned dry towers typically have wind screens, analogous to those provided in so-called wet towers, to control the strong winds prevailing in storms, and to minimize the disturbances in the distribution of the air inside the tower. The wind screens consist of flat, vertical walls which extend from the periphery of the tower to the extremities of the batteries, arranged in this case in a cross to divide the cooling system into quarters. 
         [0013]    The horizontal batteries are supported directly by the vertical batteries themselves and by a single circular row of poles braced by beams. The latter may, moreover, be replaced by the chimney lintel itself, or by any type of framework. Two gangplanks typically allow for the passage of those persons responsible for surveillance and maintenance of the system. 
         [0014]    With the increase of the output of steam turbines, the heat dissipating capacity of conventional indirect dry cooling plants has been required to increase accordingly. This demand has led to the use of extremely tall cooling deltas, up to 30 meters in cases, when a vertical cooling delta arrangement is applied. The cooling delta typically includes of a pair of heat exchanger bundles arranged in delta (i.e., Δ) form, with an apex angle of approximately 60 degrees. In the aforementioned delta arrangement, the two inclined sides are the two bundles, and the horizontal side is an airflow control louver assembly. The delta assembly is supplied with a self supporting prismatic steelwork. 
         [0015]    Other solutions have been proposed to increase heat dissipating capacity, for example, a single-pass heat exchanger. However, it does not provide very good heat transfer capabilities. Another example is the use of a larger tube diameter, however, it has too high a pressure drop of the liquid being cooled as the air side pressure drop increases. For good heat transfer, a cross-counter flow pattern is preferred in the deltas, which can be implemented with two passes on the waterside. However, the water has to flow through a 60 meter length of tubes, which involves a high water side pressure loss. 
         [0016]    Accordingly, there is a need and desire to provide an indirect dry cooling tower that has good heat transfer and a low pressure drop. 
       SUMMARY OF THE INVENTION 
       [0017]    Embodiments of the present invention advantageously provide an indirect dry cooling tower that has good heat transfer and a low pressure drop. 
         [0018]    An embodiment of the invention includes a heat exchange apparatus that extends vertically along a longitudinal axis, that cools a liquid, the apparatus including: a first delta positioned at a first point along the longitudinal axis, the first delta including: a first inlet conduit for inlet liquid flow, the first inlet conduit being in fluid communication with a first inlet main, and a first outlet conduit for outlet fluid flow, the first outlet conduit being in fluid communication with the first inlet conduit and a first outlet main, and a second delta positioned at a second point along the longitudinal axis above the first delta, the second delta including: a second inlet conduit for inlet liquid flow, the second inlet conduit being in fluid communication with a second inlet main, and a second outlet conduit for outlet fluid flow, the second outlet conduit being in fluid communication with the second inlet conduit and a second outlet main. 
         [0019]    Another embodiment includes a method for cooling a fluid, the method including: passing a first portion of a fluid to be cooled through a first delta, and passing a second portion of the fluid to be cooled through a second delta above the first delta, and passing air over the first and second deltas. 
         [0020]    Another embodiment includes an apparatus for cooling a liquid, the apparatus including: a means for passing a first portion of a fluid to be cooled through a means for a first delta, and a means for passing a second portion of the fluid to be cooled through a means for a second delta above the means for first delta, and a means for passing air over the means for first and second deltas. 
         [0021]    Another embodiment includes a heat exchange apparatus that extends vertically along a longitudinal axis, that cools a liquid, the apparatus including: a first delta positioned at a first point along the longitudinal axis, the first delta including: a first inlet conduit for inlet liquid flow, the first inlet conduit being in fluid communication with an inlet main, and a first outlet conduit for outlet fluid flow, the first outlet conduit being in fluid communication with the first inlet conduit and an outlet main, a second delta positioned at a second point along the longitudinal axis above the first delta, the second delta including: a second inlet conduit for inlet liquid flow, the second inlet conduit being in fluid communication with the inlet main, and a second outlet conduit for outlet fluid flow, the second outlet conduit being in fluid communication with the second inlet conduit and the outlet main. 
         [0022]    Another embodiment includes an indirect dry cooling tower for providing heat exchange to a fluid, the tower including: a delta tower, including: a first delta positioned at a first point along the longitudinal axis, the first delta including: a first inlet conduit for inlet liquid flow, the first inlet conduit being in fluid communication with a first inlet main, and a first outlet conduit for outlet fluid flow, the first outlet conduit being in fluid communication with the first inlet conduit and a first outlet main, and a second delta positioned at a second point along the longitudinal axis above the first delta, the second delta including: a second inlet conduit for inlet liquid flow, the second inlet conduit being in fluid communication with a second inlet main, and a second outlet conduit for outlet fluid flow, the second outlet conduit being in fluid communication with the second inlet conduit and a second outlet main. 
         [0023]    There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
         [0024]    In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
         [0025]    As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following description of various embodiments of the disclosure taken in conjunction with the accompanying figures, wherein: 
           [0027]      FIG. 1  is a side schematic view of an indirect dry cooling tower in accordance with an embodiment of the invention. 
           [0028]      FIG. 2  is a schematic view of a conduit orientation and structure for a delta utilized within a cooling tower in accordance with an embodiment of the invention. 
           [0029]      FIG. 3  is a schematic view of a conduit orientation and structure for a delta utilized within a cooling tower in accordance with another embodiment of the invention. 
           [0030]      FIG. 4  is a schematic view of a conduit orientation and structure within a cooling tower in accordance with an embodiment of the invention. 
           [0031]      FIG. 5A  is a top view of a cleaning system for a cooling tower in accordance with an embodiment of the invention. 
           [0032]      FIG. 5B  is a side view of the cleaning system depicted in  FIG. 5A . 
           [0033]      FIG. 6  is a perspective view of an array of deltas in accordance with an embodiment of the invention. 
           [0034]      FIG. 7  is a perspective view of a section if the  FIG. 6  array of deltas. 
           [0035]      FIG. 8  is a perspective view of a delta in accordance with an embodiment of the invention. 
           [0036]      FIG. 9   a  is a schematic view of a cooling system in accordance with the present invention. 
           [0037]      FIG. 9   b  illustrates the automatic control of the cooling water distribution between the bottom end top level 
           [0038]      FIG. 10  is a schematic view of a cooling system in accordance with the present invention. 
           [0039]      FIGS. 11A-11C  are schematic views of a delta tower in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0040]    In the following detailed description, reference is made to the accompanying drawings, which form a part hereof and show 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 them, and it is to be understood that other embodiments may be utilized, and that structural, logical, processing, and electrical changes may be made. It should be appreciated that any list of materials or arrangements of elements is for example purposes only and is by no means intended to be exhaustive. The progression of processing steps described is an example; however, the sequence of steps is not limited to that set forth herein and may be changed as is known in the art, with the exception of steps necessarily occurring in a certain order. 
         [0041]    The invention will now be described with reference to the drawing figures in which like reference numerals refer to like parts throughout. Referring now to  FIG. 1 , an indirect dry cooling tower  100 , having a total height  101  and a cooling delta tower  110 , is depicted. The cooling delta tower  110  includes of a pair of heat exchanger bundles  820 ,  830  (see  FIG. 8 ) arranged in delta (i.e., Δ) form, with an apex angle of approximately 40-60 degrees. The two inclined sides are the two bundles, and the third side is an airflow control louver assembly  810  ( FIG. 8 ). The delta assembly may include a frame network  840  ( FIG. 8 ), for example, a self supporting prismatic steelwork. 
         [0042]    Referring back to  FIG. 1 , the delta tower  110  includes two similar shortened deltas  104 ,  105  on a water side, which are installed vertically on a vertical axis, on top of one another, forming a bottom level  106  and a top level  107 . The deltas  104 ,  105  may be positioned around the periphery of the tower  100  in a vertical orientation. The bottom and top levels  106 ,  107  of the delta tower  110  are connected in parallel on the water side. By this previously described arrangement, the water flow in the shortened deltas  104 ,  105 , e.g., the bottom and top levels  106 ,  107 , will be half the height of conventional deltas, and the length of tubes (keeping the two pass, cross-counter flow pattern) is also half that of conventional high deltas. The splitting of the deltas into two, and the arranging the delta towers  110  as two shortened deltas  104 ,  105  on two levels  106 ,  107 , can drastically reduce the waterside pressure loss and the power demand of cooling water (CW) pumps. Splitting the deltas into two shortened deltas reduces the required water flow per delta to one half that of the long deltas, and hence reduces the water velocity, as well. Moreover, the aforementioned halved height reduces the velocity of the required water flow. As understood by one skilled in the art, the pressure loss is approximately proportional to the square of the velocity, so the reduced velocity reduces the pressure loss. 
         [0043]    With the above-described two-level arrangement, the effective tower height (the height which creates the draft in the tower) of the bottom level  102  differs from the effective tower height of the top level  103 . For example, the higher effective tower height of the bottom level  102  functions to induce more draft and more airflow through the bottom level deltas. In the case of identical water flow in both levels, for example, the exit water temperature of the bottom level deltas  104  is typically cooler than that of the top level. Since the exit water from the bottom and top-level coolers may differ, thermodynamic issues can arise, as mixing water flows having different temperatures increases entropy, which indicates inefficiency of the process. Therefore, it is preferred that the exit water temperature of both levels be equal to achieve maximum process efficiency. Accordingly, in order to achieve similar or equal exiting water temperature, the cooling water flow through the top-level deltas  105  is controlled (throttled) relative to the CW flow in the bottom level deltas  104 . Thus, embodiments of the invention include a throttling device for controlling the top-level water flow. The throttling device can be a butterfly or gate valve, a throttling orifice, or other appropriate throttling or control device. Such a throttling device is described in further detail below. 
         [0044]    Turning now to  FIG. 2 ,  FIG. 2  illustrates an embodiment of the invention wherein a tower  200  includes bottom level outlet and inlet mains  201   a ,  201   b , top level outlet and inlet mains  202   a ,  202   b . The tower  200  further includes a bottom level cooling delta  203 , a top level cooling delta  204  above the bottom level cooling delta  203  on a vertical axis, bottom level lower headers  205   a ,  205   b , top level lower headers  206   a ,  206   b , a bottom level upper header  207 , and a top level upper header  208 . One bottom level lower header  205   b  and one upper level lower header  206   b  are inlet conduits. The other bottom level lower header  205   a  and other upper level lower header  206   a  are outlet conduits. The tower  200  also has a first connecting conduit  210  that extends between the inlet mains  201   b ,  202   b  on the bottom and top levels, e.g., levels  106 ,  107 , a second connecting conduit  211  that extends between the outlet mains  201   a ,  202   a  of the bottom and top levels, e.g., levels  106 ,  107 , and a throttle valve  212  to control the cooling water flow from the top level delta  204 . As depicted in  FIG. 2 , the arrows indicate the direction of the flow of liquid, e.g., water, in the deltas. As also illustrated in  FIG. 2 , the tower shell  213  extends above the height of the upper header  208 . The connecting conduits  210 ,  211  may each be a large-diameter tube, capable of supplying the cooling water for a number of towers  200 . The connecting conduits  210 ,  211  may also be bundles of small-diameter tubes, which may require less pressure than a single large-diameter tube. 
         [0045]    The control or throttling of the cooling water flow from the top level delta  204  can be implemented such that both the bottom and top levels  106 ,  107  of the tower  100  are equipped with outlet and inlet mains  201   a ,  201   b ,  202   a ,  202   b . Accordingly, the bundles of the deltas, e.g., shortened deltas  104 ,  105 , are connected to these mains  201   a ,  201   b ,  202   a ,  202   b , and the throttling device  212  is built into the connecting conduit  211  between the outlet mains  201   a ,  202   a . The throttling device  212  can be a butterfly or gate valve, a throttling orifice, or other appropriate throttling or control device. 
         [0046]    Referring to  FIG. 2 , during operation, heated liquid, e.g., water, flows from the bottom level inlet main  201   b  into the first connecting conduit  210 , and from the first connecting conduit  210  into the top level inlet main  202   b . A portion of the heated water is diverted into the top delta  204 , while the remaining water is diverted to the bottom delta  203 . In each delta  203 ,  204 , the heated water flows upward, as indicated by the arrows, then downward, where it comes in contact with air that indirectly cools the water before exiting the deltas  203 ,  204 . In order to maintain the same temperature exiting both deltas,  203 ,  204 , water in the second connecting conduit  211  may be throttled to slow the flow by the throttling device  212  such as a valve or the like. 
         [0047]    Large natural draft cooling towers similar to the above-discussed towers  100 ,  200  may be divided into four to twelve similar sectors that allow for easy and safe filling and draining operations. The individual natural draft cooling sectors can be filled, drained, and operated independently from each other. 
         [0048]    A thermometer (not shown) or similar temperature gauge may provide a temperature reading that may assist in controlling the throttling device  212  in such a way that the exit temperature of liquid from the top level  105  should preferably be approximately equal with that of the exit temperature of liquid from the bottom level  104 . The thermometer or temperature gauge may be installed into the bottom level outlet main  201   a  and another one into the top level outlet main  202   a  and connecting these thermometers to an electronic or other type control device. 
         [0049]      FIG. 3  shows another embodiment in which a tower  300  includes bottom level outlet and inlet mains  301   a ,  301   b , a bottom level cooling delta  302 , a top level cooling delta  303  above the bottom level cooling delta  302  on a vertical axis, bottom level lower headers  304   a ,  304   b , top level lower headers  305   a ,  305   b , a bottom level upper header  306 , and a top level upper header  307 . The tower  300  further includes a connecting conduit  309  that extends between the inlet main  301   b  on the bottom level and the top level lower header  305   b . The tower  300  may also have a connecting conduit  310  that extends between the outlet main  301   a  on the bottom level and the cooling deltas lower header  305   a  on the top level. There may also be an optional throttling orifice  311 . As depicted in  FIG. 3 , the arrows indicate the direction of the flow of liquid, e.g., water, in the deltas. The tower shell  312  extends above the height of the upper header  307 . The connecting conduits  309 ,  310  may each be a conduit having a large diameter or bundles of small tubes, which may require less pressure than a single large tube. In a preferred embodiment, the connecting conduits  309 ,  310  may each be a conduit having a pair of small-diameter pipes belonging to each set of bottom and top level cooling deltas  302 ,  303 , feeding each top level cooling delta  303  separately. The operation of this configuration may be similar to that of tower  200  discussed in connection with  FIG. 2 . 
         [0050]    As illustrated in  FIG. 3 , the control or throttling can be implemented such that the outlet and inlet mains  301   a ,  301   b  are on the bottom level only, e.g., for delta  302 . In such an arrangement, the top level delta  303  has cooling water supply (inlet) and return (outlet) pipes  309 ,  310 , e.g., connecting conduits. The diameter of these pipes  309 ,  310  could be selected, e.g., by calculation, to provide the necessary throttling effect. The pipes  309 ,  310  may optionally be composed of multiple small-diameter pipes. The bottom level delta  302  may also be fed from the mains  301   a ,  301   b  with additional connecting pipes similar to pipes  309 ,  310 , which may also be smaller diameter pipes. Another option may be to install throttling orifices  311  into any or all of the return pipes  310  of the top-level delta  303 . 
         [0051]    Turning now to  FIG. 4 ,  FIG. 4  depicts a tower  400  wherein top and bottom deltas  401 ,  402  are connected to the sector distributing and cooling conduits  421   a  and  421   b . Liquid, e.g., to be cooled is pumped to the deltas  401 ,  402  via an input line  404 . The cooled water flows or returns to a surface condenser  406  via output line  405 . Arrows indicate the direction of water flow. A temperature gauge, such as a thermometer  407 , may monitor the ambient temperature to allow for adjustments based on expected cooling speeds. Heated water may be sent from a divided header  408  in the condenser  406  by a cooling water pump  409  to each delta  401 ,  402 . Cooled water returns via a return line  410  to a header  408  in the condenser  406 . Each delta sector  420 - 427  may have a respective pair of top and bottom deltas  401 ,  402 , each connected to the respective sector distributing and collecting pipes  421   a  and  421   b . A tower  400  may have multiple such sectors. The tower  400  may have a single connected pipe system ( 410   a  and  410   b ) connecting the heated water input from the cooling water pump  409 , through the pipe  410   a , and back to the return line  410 . 
         [0052]      FIGS. 5A-5B  illustrate a cleaning system  500  for a pair of deltas  505 ,  510 , in which a spray device  515  sprays water or another cleaning material into the deltas  505 ,  510 . The spray device  515  may be supplied with cleaning material via pump system  520 . Multiple spray devices  515  may be used along the length of the deltas  505 ,  510 . The cleaning system  500  may remove debris from the tower, e.g., towers  100 ,  200 ,  300 ,  400 , to ensure better air flow into the deltas. 
         [0053]    Turning now to  FIG. 6 , an array  600  of deltas  610  in a ring foundation is depicted. Each delta  610  includes a top delta  620  and a bottom delta  630 . Each delta may reside in a sector, such as the sectors  420 - 427  of tower  400 .  FIG. 7  illustrates a portion  700  of the array  600 . As can be seen, each top and bottom delta  710 ,  720  includes a respective louver assembly  730  and pair of heat exchanger bundles  740 ,  750  arranged in a triangular form, with an apex angle of 60 degrees (thus the teen, “delta”).  FIG. 8  shows a detailed view of a delta  800 , which may be either a top or bottom delta, e.g., top and bottom deltas  710 ,  720 . The delta  800  includes a louver assembly  810  and pair of heat exchanger bundles  820 ,  830  arranged in a triangular form. A frame  840 , which may be a self supporting prismatic frame, and which can be constructed from, e.g., steel, supports the heat exchanger bundle structures  820 ,  830 . 
         [0054]    Turning now to  FIG. 9   a , a cooling system  900  may include a steam turbine  901 , a surface condenser  902 , a cooling water (CW) pump  903 , feed water  904 , a CW return main  905 , a CW forward main  906 , a tower return ring main  907 , a tower forward ring main  908 , a sector return pipe  909 , a sector forward pipe  910 , and a delta tower  911 . The delta tower  911  may include a common steelwork  912 , a delta CW return pipe,  913 , a delta CW forward pipe  914 , a lower delta  915 , an upper delta  916 , a lower split header  917 , and an air vent  918 . 
         [0055]      FIG. 9   b , illustrates the automatic control of the cooling water distribution between the bottom end top level a cooling system, it may include a controller  921 , a temperature measuring device  922  on the top level delta  924 , a temperature measuring device  923  on the bottom level delta  925 , the top level delta  924 , the bottom level delta  925 , a throttle valve  926 , a sector return pipe on the top level  927 , a sector forward pipe on the top level  928 , a sector return pipe on the bottom level  929 , a sector forward pipe on the bottom level  930 , the tower return ring main  931 , a tower forward ring main  932 , a sector isolating valve in the return pipe  933  and a sector isolating valve  934  in the forward pipe. 
         [0056]      FIG. 10  shows a cooling system  1000  that may include a steam turbine  1001 , a jet condenser  1002 , a cooling water (CW) pump  1003   a , a recovery hydroturbine  1003   b , feed water  1004 , a CW return main  1005 , a CW forward main  1006 , a tower return ring main  1007 , a tower forward ring main  1008 , a sector return pipe  1009 , a sector forward pipe  1010 , and a delta tower  1011 . The delta tower  1011  may include a common steelwork  1012 , a delta CW return pipe,  1013 , a delta CW forward pipe  1014 , a lower delta  1015 , an upper delta  1016 , a lower split header  1017 , and an air vent  1018 . 
         [0057]    Depicted in  FIGS. 11A-11C  are various views of a delta tower  1100 .  FIG. 11A  illustrates the delta tower  1100 , which may include an upper delta  1105 , lower delta  1110 , louvers  1115 , and steelwork  1120 . The upper delta  1105  may include an upper header  1125  and lower header  1130 . The lower delta  1110  may include a lower header  1135  and an upper header (e.g.,  207 ,  306 ).  FIG. 11B  further shows a bundle  1135  on one side of the delta tower  1100 .  FIG. 11C  additionally depicts an inlet nozzle  1145  for receiving water to be cooled and an outlet nozzle  1150  for providing cooled water. Both nozzles  1145 ,  1150  may be located in between the upper delta  1105  and lower delta  1110 . 
         [0058]    The processes and devices in the above description and drawings illustrate examples of only some of the methods and devices that could be used and produced to achieve the objects, features, and advantages of embodiments described herein. Thus, they are not to be seen as limited by the foregoing description of the embodiments, but only limited by the appended claims. Any claim or feature may be combined with any other claim or feature within the scope of the invention. 
         [0059]    The many features and advantages of the invention are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and, accordingly, all suitable modifications and equivalents may be resorted to that fall within the scope of the invention.