Abstract:
A waste heat recovery system is provided where a waste heat source is utilized to vaporize a working fluid which in turn powers a turbine to generate power in a heat engine. A heat exhanger is placed between a waste heat source in an industrial process and an evaporator. The evaporator is connected to a turbine chamber further connected to a multi-chambered condensation unit. Each chamber of the multi-chambered condensation unit has a valved inlet port and a valved outlet port. The valved inlet ports of each chamber of the multi-chambered condensation unit are connected to the turbine chamber outlet. The multi-chamber condensation unit includes a number of condensation chambers, each chamber including a plurality of computer controlled valves. The condesation chambers are sequentially evacuated causing the vapor to be drawn through the turbine and brought into the condensation chambers one at a time. A reservoir is provided which collects the condensate where it is pumped back to the evaporator. May be easily retrofitted into waste heat disposal systems of many industrial processes to permit reclaimation of that heat.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to heat engines for waste heat recovery, and more particularly, to a waste condensation system which employs a heat engine utilizing a turbine and multiple condensation units which are sequentially evacuated, filled and purged. 
     It is often desirable to employ a system to recycle or reclaim heat generated from industrial or other processes. This waste heat is usually dumped into the environment, warming the atmosphere or a local sink such as a river or other body of water. This heat pollution has adverse environmental impact and is not desireable. Also, by employing this process one generates energy which is useable from an industrial or other thermal processes utilizing the waste heat recovery system. The process described herein is for a generally closed loop system, and incorporates principles set forth in U.S. patent application Ser. No. 02/229,318 cited here for reference. 
     It is also desirable to utilize natural heat sources for power generation such as geothermal or solar thermal heating means. By employing this process some power generation may be accomplished via such natural heating. When this process is used where extremes of heat and cold, and a vacuum supply are naturally available the highest power generation efficiency is achieved. Examples of such extreme circumstances would be extra-terrestrial environments, such as an orbital space station or a lunar base. 
     The apparatus disclosed herein is designed to employed in such environments, and may be easily retrofitted into many existing waste heat disposal devices presently employed in industrial processes without substantial modification of the industrial plant. 
     SUMMARY OF THE INVENTION 
     To achieve the foregoing and other advantages, the present invention, briefly described, pertains to a waste heat recovery system where a closed cycle heat engine is provided as a waste heat reclaimation unit in an industrial process. The engine includes a heat exchanger employed intermediate a waste heat source and an evaporator or vapor generator. The evaporator is connected to a turbine chamber which is further connected to a multi-chambered condensation unit. Each chamber of the multi-chambered condensation unit has a valved inlet port and a valved outlet port. The valved inlet ports of each chamber of the multi-chambered condensation unit are connected by piping or similar structure to the turbine chamber outlet. Each condensation chamber is provided with another valved port which is connected by piping or other similar structure to a vacuum generating means such as an evacuating pump. Each chamber is also provided with a further valved port connected by piping or other similar structure to a purge pump. The valved outlet ports are connected to a fluid reservoir by piping or other similar structure. All of the valves are opened and closed by valve control means such as a computer or spring actuators sensitive to differential pressure. The valve control means opens and closes the valved vacuum line, valved inlet ports, valved outlet ports, and valved purge line in a sequence to permit a condensable vapor to be continuously drawn through the turbine chamber where it rotates the turbine blades transferring energy from the vapor to the turbine shaft. As a result of this loss of energy the vapor condenses. The condensate is further sequentially drawn into the condensation chambers by the negative pressure therein. The automatic sequence of valves opening and closing is such that one condensation chamber is always filling with condensate, one condensation chamber is always being evacuated (having vacuum established) and one condensation chamber is always being drained of condensate through the use of positive air pressure supplied by a purge pump into the reservoir when the automatic valve sequence has achieved a steady state. The condensate is then pumped from the reservoir back to the evaporator, thus closing the system. Different working fluids may be utilized for different specific applications, iso-butane appears to have desireable thermodynamic properties for some waste heat extraction applications but other polyatomic molecules may be successfully employed. The turbine shaft may be connected to a load such as a generator or blower. 
     A minimum of three chambers are required; however, more may be utilized. In one of the three chamber embodiments, each chamber has four different valved ports which may be computer controlled or spring actuated by differential pressure between the chambers and structures in communication said chambers. They include a valved condensate input or entrance port, a valved condensate output or exit port, a valved vacuum port and a valved purge port. The valved condensate input port is connected to the turbine exit, the valved condensate output port is connected to the reservoir. The valved purge port is connected to a purge pump and the valved vacuum port is connected to a vacuum pump. 
     The valved condensate input port of each condensation chamber is connected by piping or other similar structure to the turbine exit. This piping is in communication with each of the condensation chambers and in the three chamber embodiment has three branches from the turbine. Each branch of the condensate line connects to the valved condensate input port of each chamber. 
     The valved vacuum port of each condensation chamber is connected by piping or other similar structure to a vacuum pump. This piping is in communication with each of the condensation chambers and in the three chamber embodiment has three branches from the vacuum pump. Each branch of the vacuum line connects to the valved vacuum port of each chamber. 
     The valved purge port of each condensation chamber is connected by piping or other similar structure to a purge pump. This piping is in communication with each of the condensation chambers and in the three chamber embodiment has three branches from the purge pump. Each branch of the purge line connects to the valved purge port of each chamber. 
     The valved condensate output port of each condensation chamber is connected by piping or other similar structure to the reservoir. The piping is in communication with each of the condensation chambers and in the three chamber embodiment has three branches connecting the valved output port of each chamber to the reservoir. 
     The waste heat recovery system utilizes a four phase operational sequence of valve states for the three chamber embodiment. The addition of another chamber, or plurality of chambers, will require the addition of another phase, or a plurality of additional phases, for the sequence of valve states. The additional condensation chambers are structurally identical to the condensation chambers discussed herein and the valves thereon are responsive to the selected control means. The valve state matrix is explained in detail in the description of the preferred embodiment. 
     The above brief description sets forth rather broadly the more important features of the present invention in order that the detailed description thereof that follows may be better understood, and in order that the present contributions to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining the preferred embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood, that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
     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 designing 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. 
     Further, the purpose of the foregoing Abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms of phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. Accordingly, the Abstract is neither intended to define the invention or the application, which only is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. 
     It is an object of the present invention to provide a waste heat recovery system employing a closed cycle heat engine which may be retrofitted into existing industrial processes with a minimal refit cost and modification of existing systems. 
     It is an object of the present invention to provide a heat engine which may be used in extra-terestrial environments where extremes or heat and cold, and a vacuum supply are naturally occuring. 
     It is an object of the present invention to provide a waste heat recovery system which utilizes a turbine to transfer energy from the vapor to the turbine shaft such that a portion of the waste energy from the process will be reclaimed and utilized. 
     It is still a further object of the present invention is to provide a waste heat recovery system which utilizes valve sequencing to continuously drive a turbine. 
     Still a further object of the present invention to provide a waste heat recovery system which may be easily and efficiently manufactured and marketed. 
     It is a further objective of the present invention to provide a waste heat recovery system which is of durable and reliable construction. 
     An even further object of the present invention is to provide a waste heat recovery system which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such a waste heat recovery system available to the buying public. 
     These together with still other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and the above objects as well as objects other than those set forth above will become more apparent after a study of the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
     FIG. 1 is a cross-sectional view showing the preferred embodiment of the waste heat recovery system of the invention. 
     FIG. 2 is a cross-sectional view of the valved port arrangement of a generic condensation chamber of the instant invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference now to the drawings, a new and improved waste heat recovery system embodying the principles and concepts of the present invention will be described. 
     Referring to FIG. 1 there is shown the exemplary embodiment of the waste heat recovery system of the invention wherein a waste heat sink is utilized to vaporize a working fluid which in turn rotates a turbine connected to generator to produce power in a heat engine generally designated by reference numeral 10. In its preferred form, waste heat recovery system 10 comprises generally a turbine 20 inside a housing having a turbine housing inlet 22 and a turbine housing outlet 24. A turbine shaft 25 may be connected to a load 26. The turbine housing inlet 22 is connected by piping to an evaporator or vapor generator means 15. A working fluid, such as isobutane, is vaporized in the evaporator means 15. 
     The turbine housing outlet 24 is connected by piping or other similar structure to a first condensation chamber 30, a second condensation chamber 40, and a third condensation chamber 50. A valved inlet port 32 is provided on the first condensation chamber 30, a valved inlet port 42 is provided on the second condensation chamber 42 and a valved inlet port 52 is provided on the third condensation chamber 50. The valved inlet ports 32, 42, and 52 each include a valve which is actuated (opened or closed) in a predetermined sequence depending on which phase of operation the system is utilizing. 
     A valved outlet port 34 is provided on the first condensation chamber 30. A valved outlet port 44 is provided on the second condensation chamber 40. A valved outlet port 54 is provided on the third condensation chamber 50. The valve outlet ports 34, 44, and 54 each include a valve which is actuated (opened or closed) in a predetermined sequence depending on which phase of operation the system is utilizing. 
     A reservoir 60 is connected by piping to the first condensation chamber 30, the second condensation chamber 40, and the third condensation chamber 50. The reservoir 60 includes a valved port 62. The reservoir 60 is connected by piping or other similar means to a vacuum supply 80. The reservoir acts as a further cooling means which permits any working fluid which has not yet changed state to a liquid to do so. An exit valve 67 is included to permit the condensate to be pumped back to the evaporator means 15. Pump 68 will pump the condensate from the reservoir 60 to the evaporator means 15 via pipe 16. 
     The vacuum supply 80 is connected by piping or other similar structure to the first condensation chamber 30, the second condensation chamber 40, and the third condensation chamber 50. A valved vacuum port 36 is provided on the first condensation chamber 30, a valved vacuum port 46 is provided on the second condensation chamber 40 and a valved vacuum port 56 is provided on the third condensation chamber 50. The valved vacuum ports 36, 46 and 56 each include a valve which is actuated (opened or closed) in a predetermined sequence depending on which phase of the operation the system is utilizing. 
     The vacuum supply 80 is also connected to a vapor scrubbing means 82. Said vapor scrubbing means may include an adsorption filter or oxidizer and will remove residual non-condensed vapors from the air stream prior to elimination through exhaust 84. Such residual losses may require that the working fluid be replenished periodically. 
     The purge pump 70 is connected by piping or other similar structure to the first condensation chamber 30, a second condensation chamber 40 and a third condensation chamber 50. The purge pump 70 provides a positive air pressure for a predetermined duration of time, which causes the condensation chambers to sequentially empty with a minimum introduction of pressurized air. A valved purge port 38 is provided on the first condensation chamber 30, a valved purge port 48 is provided on the second condensation chamber 40, and a valved purge port 58 is provided on the third condensation chamber 50. The valved purge ports 38, 48 and 58 each include a valve which is actuated (opened or closed) in a predetermined sequence depending on which phase of the operation the system is utilizing. 
     Valves are controlled by a central valve control means 100. Said valve control means may be a computer which uses a signal generation protocol to provide an on/off actuation signal to open/close valves as required to sustain the process. Certain valves, when the device is operating in a steady-state mode, will be spring actuated due to differential pressure between the chambers and the structures in communication therewith. However, such does not obviate the need for computer control at start-up and shut-down. The pressure state inside the various structures will be monitored in real-time via signals from pressure transducers in communication with valve control means 100. The pressure data communicated is included in the signal generation protocol to determine optimal times for valve sequencing. 
     The following tables show the phase of operation of the system, the valves states at that point and the sequence of valve actuation during the operation of the waste heat recovery system. 
     Referring now to Tables 1-5, with respect to the valved elements described in FIG. 1, the sequence of operation is described. Table 1 refers to the situation during the start up phase of the sequence. In the start-up phase of operation of the waste heat recovery system, all of the condensation chambers 30, 40, and 50 are evacuated to an initial sub-ambient pressure P 0 . The initial valve states are described in Table 1. 
     
                       TABLE 1______________________________________VALVE STATES AT START UPVALVE  VALVE STATE  LOCATION OF VALVE______________________________________32     CLOSED       FROM TURBINE TO               CHAMBER34     CLOSED       FROM CHAMBER TO               RESERVOIR36     OPEN         VACUUM MEANS TO               CHAMBER38     CLOSED       FROM PURGE MEANS TO               CHAMBER42     CLOSED       FROM TURBINE TO               CHAMBER44     CLOSED       FROM CHAMBER TO               RESERVOIR46     OPEN         FROM VACUUM MEANS TO               CHAMBER48     CLOSED       FROM PURGE MEANS TO               CHAMBER52     CLOSED       FROM TURBINE TO               CHAMBER54     CLOSED       FROM CHAMBER TO               RESERVOIR56     OPEN         FROM VACUUM MEANS TO               CHAMBER58     CLOSED       FROM PURGE MEANS TO               CHAMBER62     OPEN         FROM EMPTY RESERVOIR               TO VACUUM MEANS67     CLOSED       FROM EMPTY RESERVOIR               TO EVAPORATOR______________________________________ 
    
     Referring now to Table 2 a vapor is generated in the evaporator means 15 through the application of heat to a material containing a liquid. Thus the vapor diffuses through the turbine inlet 22 to the turbine 20, where the valved vacuum ports 36, 46, 56 and 62 are closed. Valved vacuum port 62 is always closed except at the start-up. Valved inlet port 32 is opened and the pressure drop across the turbine inlet 22 and turbine outlet 24 causes the vapor to expand into the turbine 20, causing the turbine 20 to rotate and thus transferring energy from the vapor to the turbine shaft 25. This process is called the Initiation Sequence. The valve states are depicted in Table 2. 
     
                       TABLE 2______________________________________INITIATION SEQUENCEVALVE  VALVE STATE  LOCATION OF VALVE______________________________________32     OPEN         FROM TURBINE TO               CHAMBER34     CLOSED       FROM CHAMBER TO               RESERVOIR36     CLOSED       FROM VACUUM MEANS TO               CHAMBER38     CLOSED       FROM PURGE MEANS TO               CHAMBER42     CLOSED       FROM TURBINE TO               CHAMBER44     CLOSED       FROM CHAMBER TO               RESERVOIR46     CLOSED       FROM VACUUM MEANS TO               CHAMBER48     CLOSED       FROM PURGE MEANS TO               CHAMBER52     CLOSED       FROM TURBINE TO               CHAMBER54     CLOSED       FROM CHAMBER TO               RESERVOIR56     CLOSED       FROM VACUUM MEANS TO               CHAMBER58     CLOSED       FROM PURGE MEANS TO               CHAMBER62     CLOSED       FROM RESERVOIR               TO VACUUM MEANS67     CLOSED       FROM RESERVOIR               TO EVAPORATOR______________________________________ 
    
     The next sequence, Sequence #1, described in Table 3, initiates when the pressure in the first condensation chamber 30 reaches a final value P f . The pressure may be transduced by any of a variety of pressure sensors. Valved inlet port 32 is closed and valved inlet port 42 is opened to allow for a concurrent process. Valved purge port 38 is opened to allow the pressure to increase in the first condensation chamber 30 to achieve some purge pressure P p , and then valved outlet port 34 is opened to purge the liquid and vapor contents of the first condensation chamber 30 into the reservoir 60. The 
     
                       TABLE 3______________________________________SEQUENCE #1VALVE  VALVE STATE  LOCATION OF VALVE______________________________________32     CLOSED       FROM TURBINE TO               CHAMBER34     OPEN         FROM RESERVOIR TO               CHAMBER36     CLOSED       FROM VACUUM MEANS TO               CHAMBER38     OPEN         FROM PURGE MEANS TO               CHAMBER42     OPEN         FROM TURBINE TO               CHAMBER44     CLOSED       FROM RESERVOIR TO               CHAMBER46     CLOSED       FROM VACUUM MEANS TO               CHAMBER48     CLOSED       FROM PURGE MEANS TO               CHAMBER52     CLOSED       FROM TURBINE TO               CHAMBER54     CLOSED       FROM RESERVOIR TO               CHAMBER56     CLOSED       FROM VACUUM MEANS TO               CHAMBER58     CLOSED       FROM PURGE MEANS TO               CHAMBER62     CLOSED       FROM RESERVOIR               TO VACUUM MEANS67     CLOSED       FROM RESERVOIR               TO EVAPORATOR______________________________________ 
    
     valve states for Sequence #1 are described in Table 3. 
     The next sequence, Sequence #2, described in Table 4, may have two possible configurations depending upon the purge rate of the first condensation chamber 30 relative to the fill rate of the second condensation chamber 40. In Table 4, the purge rate of the first condensation chamber 30 is greater than the fill rate of the second condensation chamber 40. In this case, the first condensation chamber 30 is being evacuated while the second condensation chamber 40 is still filling. The third condensation chamber is still evacuated awaiting it&#39;s turn in the cycle. 
     
                       TABLE 4______________________________________SEQUENCE #2VALVE  VALVE STATE  LOCATION OF VALVE______________________________________32     CLOSED       FROM TURBINE TO               CHAMBER34     CLOSED       FROM RESERVOIR TO               CHAMBER36     OPEN         FROM VACUUM MEANS TO               CHAMBER38     CLOSED       FROM PURGE MEANS TO               CHAMBER42     OPEN         FROM TURBINE TO               CHAMBER44     CLOSED       FROM RESERVOIR TO               CHAMBER46     CLOSED       FROM VACUUM MEANS TO               CHAMBER48     CLOSED       FROM PURGE MEANS TO               CHAMBER52     CLOSED       FROM TURBINE TO               CHAMBER54     CLOSED       FROM RESERVOIR TO               CHAMBER56     CLOSED       FROM VACUUM MEANS TO               CHAMBER58     CLOSED       FROM PURGE MEANS TO               CHAMBER62     CLOSED       FROM RESERVOIR               TO VACUUM MEANS67     OPEN         FROM RESERVOIR               TO EVAPORATOR______________________________________ 
    
     The next sequence, SEQUENCE #3, described in Table 5, llows for the second condensation chamber 40 to be purged while the third condensation chamber 50 is being evacuated and the first condensation chamber 30 is being filled. 
     
                       TABLE 4______________________________________SEQUENCE #3VALVE  VALVE STATE  LOCATION OF VALVE______________________________________32     CLOSED       FROM TURBINE TO               CHAMBER34     CLOSED       FROM RESERVOIR TO               CHAMBER36     OPEN         FROM VACUUM MEANS TO               CHAMBER38     CLOSED       FROM PURGE MEANS TO               CHAMBER42     CLOSED       FROM TURBINE TO               CHAMBER44     OPEN         FROM RESERVOIR TO               CHAMBER46     CLOSED       FROM VACUUM MEANS TO               CHAMBER48     OPEN         FROM PURGE MEANS TO               CHAMBER52     OPEN         FROM TURBINE TO               CHAMBER54     CLOSED       FROM RESERVOIR TO               CHAMBER56     CLOSED       FROM VACUUM MEANS TO               CHAMBER58     CLOSED       FROM PURGE MEANS TO               CHAMBER62     CLOSED       FROM RESERVOIR               TO VACUUM MEANS67     OPEN         FROM RESERVOIR               TO EVAPORATOR______________________________________ 
    
     The process is then continued cyclically with the vapor providing energy to rotate the turbine shaft 25 which may be connected to a load 26. Successive vapor losses may require periodic replenishing of the working fluid. 
     Referring now specifically to FIG. 2, a condensation chamber 90 is shown. This is a generic condensation chamber which may be added to the waste heat recovery system shown in FIG. 1. A valved inlet port 92 is shown which includes a valve which may be operated in a predetermined sequence by valve control means 100. Valve 92 may also be spring actuated according to the differential pressure between the evaporator means (15 in FIG. 1) and the chamber 90. Arrow 93 designates the direction of flow from the turbine. A valved outlet port 94 is shown which includes a valve which may be operated in predetermined sequence by the valve control means 100. Valve 94 may also be spring actuated according to the differential pressure between the reservoir (60 in FIG. 1) and the chamber 90. Arrow 95 designates the direction of flow from the condensation chamber 90 to the reservoir (60 in FIG. 1). A valved vacuum port 96 is shown which includes a valve which would be operated in predetermined sequence by valve control means 100. Arrow 97 designates the direction of flow from the condensation chamber 90 to the vacuum generating means. A valved purged port 98 is shown which includes a valve is operated in a predetermined sequence by the valve control means 100. Arrow 99 indicates the direction of flow from the purge pump to the condensation chamber. 
     It is apparent from the above that the present invention accomplishes all of the objectives set forth by providing a waste heat recovery system which utilizes a turbine to transfer energy from the vapor to the turbine shaft, which utilizes valve sequencing to continuously drive the turbine, and permits the condensation of the vapor as well as the collection of the condensate. 
     With respect to the above description, it should be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to those skilled in the art, and therefore, all relationships equivalent to those illustrated in the drawings and described in the specification are intended to be encompassed only by the scope of appended claims. 
     While the present invention has been shown in the drawings and fully described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiments of the invention, it will be apparent to those of ordinary skill in the art that many modifications thereof may be made without departing from the principles and concepts set forth herein. Hence, the proper scope of the present invention should be determined only by the broadest interpretation of the appended claims so as encompass all such modifications and equivalents.