Patent Document

CROSS REFERENCE TO RELATED APPLICATIONS (IF APPLICABLE) 
     This application is a divisional application of U.S. patent application Ser. No. 13/191,554 entitled “Hyper-Condensate Recycler” filed on Jul. 27, 2011, which claims priority to U.S. Provisional Application Ser. No. 61/369,299 entitled “Hyper Condensate Recycler” filed on Jul. 30, 2010 the contents of both which are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein relates to a device for use in a district steam heating system, and in particular to a device that recycles condensate to reduce consumption by end users and reduce discharges into sewer systems. 
     In large metropolitan areas, it is not uncommon for a central boiler system to be used to generate heat for multiple facilities in the surrounding area. This heating system is sometimes referred to as district heating. The steam is transported via insulated pipes to subscribing buildings, which purchase the steam from the steam utility. Similar to an electric meter, a steam meter measures the amount of steam used by a particular building and the building owner is charged on a periodic basis. 
     Some of the facilities that receive steam from the district heating system distribute the steam through the building steam-based space heating system, other facilities convert the steam into hot water in tube and shell heat exchangers. In the latter system, the hot water is then distributed by electrically driven pumps through-out the building for space heating and domestic hot water service. After the steam is utilized in either application, the resulting condensate is typically discharged to the city sewer system. In order to reduce the condensate temperature from 215-220 F to about 150 F (a typical city sewer requirement) the condensate is mixed with cold potable water. 
     The routing of the condensate into the sewer system is a convenient means for disposing of the condensate. However, the facility owner or the district heating system provider is charged a fee based on the amount of waste, including condensate water, that is discharged into the sewer system. Further, since cold water is mixed with the condensate to reduce the temperature, usable energy is wasted and discharge fees are increased. 
     Accordingly, while existing district heating systems are suitable for their intended purposes a need for improvement remains, particularly in reducing the amount of condensate discharge and in increasing the extraction of energy from the delivered steam. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one aspect of the invention, a system for heating a facility is provided. The system includes a first inlet from a district heating system. A heating system is provided having a condensate outlet. A hyper-condensate recycler having a second inlet is coupled to the condensate outlet and a third inlet coupled to the first inlet, the hyper-condensate recycler having a first outlet. A separator having a fourth inlet is coupled to the first outlet, the separator further having a second outlet fluidly coupled to the first inlet. 
     According to another aspect of the invention, a system for recycling condensate within a heating system is provided. The system includes a heat exchanger having a steam inlet and a condensate outlet. A condensate tank is fluidly coupled to the heat exchanger. A hyper-condensate recycler having a first inlet is fluidly coupled to the steam inlet and a second inlet coupled to the condensate tank. A separator is fluidly coupled to receive a fluid output from the hyper-condensate recycler and first outlet fluidly coupled to the steam inlet and a second outlet fluidly coupled to the condensate tank. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic view of a district heating system having a condensate recycling device in accordance with an embodiment of the invention; 
         FIG. 2  is a schematic view of a district heating system having a condensate recycling device in accordance with an embodiment of the invention; and 
         FIG. 3  is a side sectional view of a condensate recycling device for use in the district heating system of  FIG. 1  or  FIG. 2 . 
     
    
    
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the present invention provide advantages in a condensate recycling device that allows for conversion of the internal energy of heated liquid into useful work. In embodiments of the invention, the heated liquid becomes a two-phase medium and enters a transonic phase, manifesting itself by converting thermal to kinetic energy and harvesting the energy release from the collapsed bubbles to increase the temperature in the outlet flow. This allows heat transfer from a lower temperature stream to a higher temperature stream to become possible. Advantages are gained by highly-efficient direct contact heating, and reducing or eliminating the expenditure of energy (hot water pump) while obtaining useful work. Embodiments of the condensate recycler allow for: the re-introduction of waste condensate into the steam/water mix thereby recovering the latent heat of vaporization of the condensate; the regeneration of steam from the mixed fluid at a desired pressure; reduction or elimination of water use to cool condensate prior to discharge to sewer; and reduction of overall steam consumption by the end users which consequently reduces water discharge to the sewer system. 
     Referring now to  FIG. 1  and  FIG. 3 , a system  20  in an end user facility is provided that receives steam from a district heating system  22 . The steam is supplied to a heating system  24  having a heat exchanger that transfers thermal energy from the steam to a building hot water system to the desired temperature. The steam condensate produced in the heating system  24  is collected in a condensate tank  26 . From the condensate tank  26 , a pump  28  transfers the condensate into the hyper-condensate recycler  30 . It should be appreciated that the system  20  may include additional control devices such as but not limited to flow meters  32 , temperature gauges  34 , pressure gages  36  and valves for example. 
     In parallel with the condensate from tank  26 , the hyper-condensate recycler receives steam from by-pass pipe  38  that is diverted from the incoming steam prior to the heating system  24 . The hyper-condensate recycler  30  is shown in  FIG. 3  receives liquid condensate via a nozzle  40  and steam from conduit  38  via nozzle  42 . The condensate then enters a diffuser  44  having ribs  46  that induce rotational turbulent flow into the condensate flow. Similarly, the steam is directed into a diffuser  48  having multiple de Laval nozzles. In the exemplary embodiment, the concentric orifices  50  in the adjacent rim in lower fluid pressure areas are 8 millimeters in diameter while smaller 3-millimeter diameter orifices are arranged in higher-pressure areas. 
     From the diffusers  44 , the condensate flow enters an open mixing chamber  52  to be induced by de Laval orifices  50  from diffuser  48 . In the exemplary embodiment, the length of the mixing chamber  52  is 18-27 millimeters. In the mixing chamber  52 , a partial liquid stream  54  is recirculated from an exit nozzle  58  via a concentric conduit  56 . The mixed flow is further discharged into a co-axial nozzle that reduces the flow area of the rotational turbulent flow to tangentially compress the mixed flow towards the orifice of a de Laval nozzle  60 . A chamber  62  includes ribs  64  that have sharp edges that elevate the Reynolds number and induce turbulence. 
     A fluid flow then proceeds into the nozzle  58  where the compressed fluid expands. In the exemplary embodiment, the nozzle  58  is 7.5 millimeters from the de Laval nozzle  60  and the nozzle  58  have an angle of 48 degrees. At this point, a partial liquid stream is separated and recirculated into the conical conduit  56 . The partial liquid stream flows with a laminar flow through the conduit  56  to create an elevated liquid pressure at the conduit  56  output at chamber  52 . 
     From the nozzle  58 , the main liquid stream enters the exit discharge section  66 . The discharge section  66  has ribs  68 . The ribs  68  induce laminar flow in the exiting fluid. The liquid exiting the hyper-condensate recycler  30  has an increased temperature from the inlet temperature, and an increased pressure from the inlet pressure. In the exemplary embodiment, the inlet temperature of the condensate stream entering the nozzle  40  is between 220-280 Fahrenheit and a pressure between 9-50 psig. The exit temperature at discharge section  66  is 224-285 Fahrenheit and a pressure between 30-150 psig. 
     The output of the hyper-condensate recycler  30  is transferred to a separator  31 . The separator  31  separates liquid condensate and steam from the output of the hyper-condensate recycler  30 . The condensate is drained via conduit  33  and transferred back to condensate tank  26 . The separated steam is transferred via conduit  35  as recovered energy back to the inlet of heating system  24  where the separated steam is reused for providing thermal energy to the facility. It should be appreciated that this reuse of the separated steam reduces the consumption of steam from the district heating system. 
     Referring now to  FIG. 2 , another embodiment of the system  20  is shown. In this embodiment, the system  20  receives steam from a district heating system via conduit  70 . The steam flows through a heat exchanger  72  that transfers thermal energy to a hot water heating loop  74 . The loop  74  is part of a heating system  76  that provides heat to desired locations within the facility. The heating system  76  may include additional control equipment such as pumps  78 , valves and gauges as is known in the art. 
     Once the thermal energy is transferred, the steam condenses and is transferred to a condensate tank  80 . The condensate is then flowed via conduit  82  via a pump  84  to the inlet of hyper-condensate recycler  30 . The hyper-condensate recycler  30  also receives steam from by-pass pipe  86  that is diverted from the incoming steam from conduit  70  upstream from the heat exchanger  72 . The hyper-condensate recycler  30  receives the steam and conduit and operates as described herein above to have an output fluid stream at a higher pressure and temperature than the incoming condensate. The output fluid stream is transferred to a separator  31  to separate condensate from the steam. The steam is transferred via conduit  88  back to conduit  70 , while the condensate is transferred from the separator  31  back to the condensate tank  80  via conduit  90 . 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Technology Category: 2