Abstract:
A refrigeration apparatus for removing heat from a high temperature region. The refrigeration apparatus wherein the high temperature region is a stream of fluid having a temperature above 160 degrees Fahrenheit. The heat from the high temperature region is used to evaporate the refrigerant in a refrigeration cycle.

Description:
RELATED APPLICATION  
       [0001]     This application claims priority from U.S. Provisional Patent Application No.: 60/785,599, filed on Mar. 24, 2006, which application is incorporated herein by reference. 
     
    
     BACKGROUND  
       [0002]     Currently, enormous amounts of waste heat are generated daily by a wide variety of industrial and commercial processes and operations. These range, typically, from waste heat from space heating operations, process steam boiler waste heat, mechanical and electrical system cooling, and the like. Typically, the waste heat is low grade, that is, it is below about 350° F., and often below about 250° F., a value so low that conventional heat recovery systems do not operate with sufficient efficiency to make recovery of energy from such sources economical. The net result is that vast quantities of waste heat are simply dumped to atmosphere, ground or water thereby contributing to the overall greenhouse effect and effectively raising the cost of operations.  
         [0003]     Many times the high temperature waste gas and vapor is vented to the atmosphere. For example, in a coal-fired power generator used to produce electricity large amounts of steam or combustion products from burning coal are placed into the atmosphere. Another example is an ethanol plant or a plant used to produce ethanol. Part of producing ethyl alcohol is to form a mash of a biomass material such as corn, or other biomass material. A dryer is used to drive off some of the water thus creating a high temperature moist air stream before further processing the mash into ethyl alcohol or ethanol. Steam is generated by this process which is vented to the atmosphere. It should also be noted that the normal products of combustion include water and carbon dioxide. These waste streams present wasted heat placed into the atmosphere. Placing heat and other waste products in the atmosphere has many disadvantages. One of the main disadvantages is the inefficiencies of the various processes in not recovering some of the heat before venting it to the atmosphere. Also places VOC&#39;s into atmosphere 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]     The invention is pointed out with particularity in the appended claims. However, a more complete understanding of the present invention may be derived by referring to the detailed description when considered in connection with the figures, wherein like reference numbers refer to similar items throughout the figures, and:  
         [0005]      FIG. 1  is a schematic diagram of a refrigeration cycle applied to a high temperature waste stream, according to an embodiment of this invention.  
         [0006]      FIG. 2  is a schematic of another embodiment of a refrigeration cycle applied to a high temperature waste stream, according to another embodiment of the invention.  
         [0007]      FIG. 3  is a schematic diagram of a refrigeration cycle applied to a high temperature waste stream, according to yet another embodiment of the invention.  
         [0008]      FIG. 4  is a schematic diagram of yet another embodiment of a refrigeration cycle or refrigeration device applied to a high temperature stream, such as high temperature waste stream, according to an example embodiment.  
         [0009]      FIG. 5  is a flow chart of a method for controlling the compressors of a waste stream and a refrigerant, respectively, according to an example embodiment.  
         [0010]      FIG. 6  is a block diagram of a computer system  2000  that executes programming for performing the above algorithm or method shown in  FIG. 5 , according to an example embodiment.  
     
    
       [0011]     The description set out herein illustrates the various embodiments of the invention, and such description is not intended to be construed as limiting in any manner.  
       DETAILED DESCRIPTION  
       [0012]     In the following description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which 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 structural and electrical changes may be made without departing from the scope of the present invention. The following description is, therefore, not to be taken in a limited sense, and the scope of the present invention is defined by the appended claims.  
         [0013]      FIG. 1  is a schematic diagram of a refrigeration cycle  100  applied to a high temperature stream  160 , according to an example embodiment of the invention. The high temperature stream  160  can be any type of stream including a high temperature waste stream. Other high temperature streams include streams within a process before venting them to atmosphere. The refrigeration cycle  100  is actually a device which includes an evaporator type heat exchanger that serves as an evaporator  130 , a heat exchanger that serves as a condenser  120 , a throttling valve  110 , and a pump compressor  170 . The evaporator type heat exchanger that serves as an evaporator  130  is placed into the high temperature stream. The heat exchanger  130  removes heat from the high temperature stream  160 , such as the waste heat stream. As shown in  FIG. 1 , the high temperature stream includes a portion that is not routed through the heat exchanger that serves as an evaporator  130 . This portion represents a portion that might be beyond the capacity of the heat exchanger  130  or a portion that may simply bypass the heat exchanger  130 . The heat exchanger  130  or any heat exchanger for that matter, can have capacities related to a volume of gas and vapor or liquid that can be routed through a heat exchanger. A refrigerant R is placed in the refrigeration loop or device  100 . The refrigerant R travels in the direction shown by the various arrows in the refrigeration device or refrigeration cycle. The refrigerant R can be any type of refrigerant or any fluid capable of changing phases or even carrying heat in various states as it passes through the refrigeration cycle or refrigeration device  100 . The heat exchanger that serves as an evaporator  130  removes heat from the high temperature stream  160 , such as any fluid stream in a ethanol plant. At the heat exchanger that serves as an evaporator, the heat may be used to vaporize the refrigerant R. Thus, the refrigerant R may enter the heat exchanger evaporator  130  as a liquid and leave in a gaseous vapor phase in embodiment of the invention. An expansion valve or other throttling mechanism  110  is then used to further expand the gas or regulate the gas vapor. The refrigerant R then enters a heat exchanger condenser  120  where heat is removed from the heat exchanger and placed into a different portion of an industrial process.  
         [0014]     The cooled refrigerant R then leaves the heat exchanger condenser as a liquid and is pumped or directed under pressure to heat exchanger evaporator  130  other compressor  170  before reentering the heat exchanger evaporator  130 . In essence, the refrigeration cycle or refrigeration device  100  is a device which removes heat from a high temperature stream and places it in a different area needing heat in an industrial process. For example, in the production of ethyl alcohol or ethanol, water and biomass are mixed to form a mash. In many ethanol plants, after a time at least a portion of the water is driven away from the mash for use as animal feed, or the like, and before the mash is further processed. The water driven off is a high temperature stream that, in the past, may have been exhausted to the atmosphere. Using the high temperature refrigeration cycle or refrigeration device  100  shown in  FIG. 1 , heat can be removed from the high temperature stream  160  and placed into another area of the ethanol plant. For example, heat removed from the high temperature waste stream  160  can be placed or used in the distillation columns of an ethanol plant. Recovering heat and placing it at different areas within a process increases the overall efficiency of the process. It should be noted that the refrigerant R used can be any type of refrigerant. In some instances, water is used as a refrigerant. In other instances, alcohol can be used as the refrigerant and in still other instances liquids designed to be refrigerants can be used. In another embodiment, high temperature azeotrope blends, such as  194  proof ethanol and water, form the refrigerant. An azetrope is a liquid mixture of two or more substances that retains the same composition in the vapor state as in the liquid state when distilled or partially evaporated under a certain pressure.  
         [0015]      FIG. 2  is a schematic diagram of another refrigeration cycle or refrigeration device  200 , according to an example embodiment of the invention. The refrigeration cycle  200  or refrigeration device  200  is applied to a high temperature stream  260 . The refrigeration device  200  includes an evaporator or heat exchanger that serves as an evaporator  230 , a heat exchanger that serves as a condenser  220 , as well as a cascade condenser evaporator  240 . The refrigeration device  200  actually includes a first refrigeration loop  201 , and a second refrigeration loop  202 . The first refrigeration loop  201  includes the heat exchanger that serves as an evaporator  230 , a throttling mechanism or expansion valve  210  and a compressor pump  270 . The first refrigeration loop  201  also includes a refrigerant R 1 . The heat exchanger that serves as an evaporator  230  removes heat from the high temperature stream  260  and turns the refrigerant R 1  into a vapor or into a higher temperature vapor, depending upon the refrigerant R 1 .  
         [0016]     The refrigerant R 1  then enters the cascade evaporator/condenser  240 . For the first refrigeration loop  201 , the cascade evaporator and condenser serve to condense the refrigerant or cooler refrigerant R 1 . The liquid refrigerant then passes out of the cascade evaporator/condenser  240  and is revaporized at  230  and again compressed by a pump or other compressor  270  before being routed once again through the heat exchanger that serves as an condenser  240 . The refrigerant R 2  passes through a refrigeration loop  202  that includes the evaporator/condenser  240 , a throttle or other valve expansion valve  212 , the condenser heat exchanger  220  and a pump or other compressor  272 . At the cascade evaporator condenser, the refrigerant R 2  is a liquid being vaporized thus condensing R 1  which picks up heat, such as the heat of vaporization. The refrigerant is either moved to a vapor state or to a higher energy carrying state after it passes through the cascade evaporator condenser  240 . The refrigerant is compressed, expanded or passed through the condenser  220  and then to throttle  212  before once again picking up the energy needed to vaporize the R 2  at evaporator/condenser  240  thus completing the cycle. The refrigerant then passes through the pump  272  or other compressor. Heat is removed from the refrigerant R 2  at the heat exchanger that serves as a condenser  220 . This heat exchanger that serves as a condenser  220  can be placed at or near any portion of a system that requires additional heat or can benefit from having high quality latent heat. The refrigeration device  200  shows that the refrigeration cycle can be cascaded or can include any number of cascades to recover further heat from the refrigerants or from the high temperature streams. Whether or not to add an additional cascading level is generally a matter of economics. It should be understood that most of the high temperature streams are at 100° F. to 160° F. or above.  
         [0017]      FIG. 3  is a schematic diagram of yet another embodiment of a refrigeration cycle or refrigeration device  300  applied to a high temperature stream, such as high temperature stream  160  or high temperature stream  260 . The high temperature stream is represented by references C and D in  FIG. 3 . The refrigeration apparatus  300  utilizes the latent heat of evaporation in a high temperature region, such as a waste stream, to maximize economic benefit. The refrigeration apparatus  300  includes a plate heat exchanger  320  that acts as an condenser evaporator, and a plate heat exchanger  330  that acts as a evaporator condenser. The refrigeration apparatus  300  also includes compressors  301   a  and  301   b  and a pump  307 . The refrigeration apparatus also includes an accumulator  306 , a separator  309  and a number of motorized valves  308   a,    308   b,    308   c  for controllably adding fluids to the refrigerant in the refrigeration loop that forms the refrigeration apparatus  300 . The waste heat stream high temperature region is depicted by the flows labeled (c) and (d) in  FIG. 3 . A refrigerant is used in a high temperature region to capture latent heat. The refrigerant changes phase from a liquid to a low quality vapor at plate heat exchanger  330 . As a result, water is separated out of a gaseous air, CO2 or other inert drying medium. The waste stream enters in counter flow manner at (c) and emerges substantially stripped of water vapor and at lower temperature at the flow arrow (d). The water condensed from the waste stream, represented by the flow arrow (h) is processed to eliminate contaminates at a device  310 . Various means are to be utilized within device  310  to neutralize Volatile Organic Compounds (VOC) and particulates and prepare the water for re-utilization within the parent industrial process. This example embodiment uses water as the refrigerant (f′) provided the humidity ratio of the waste stream permits. It should be noted that any type of fluid can be used as a refrigerant. Typically, the refrigerant must be matched to the temperatures of the high temperature region in which the refrigeration apparatus  300  is to be used. Azeotropes, in one example embodiment, are added to the water to alter the condensing temperature and pressures that would allow maximum Coefficient of Performance (“COP”) at lower humidity ratios in the waste stream (c). The low pressure refrigerant vapor is passed through the separator  306  so that no water droplets are allowed to travel into the compressor stage  301   a,  or the compressor stage  301   b  via flow (f). It should be noted that additional compressor stages may be employed in the refrigeration cycle or refrigeration apparatus  300 .  
         [0018]      FIG. 4  is a schematic diagram of yet another embodiment of a refrigeration cycle or refrigeration device  400  applied to a high temperature stream, such as high temperature waste stream  460 . The high temperature waste stream  460  can be any stream of waste water. In one embodiment, the high temperature waste stream  460  is a waste stream from a drum drying apparatus. The refrigeration device  400  includes a heat transfer device  402 , such as an evaporator heat exchanger. The waste stream includes steam having a pressure and temperature. The high temperature refrigeration device includes a compressor  410  for compressing the waste stream  460 . The waste stream  460  may include superheated steam. The compressor  410  in the waste stream  460  can then be used to control the pressure associated with the steam in the waste stream. In other words, the compressor  410  is used to adjust the boiling point of the waste stream. By increasing the pressure in the waste stream  460 , the boiling point of the fluid in the waste stream can be increased. The high temperature refrigeration device  400  also includes a refrigeration loop  430 . The refrigeration loop includes a refrigerant, R 1 , and also includes a compressor  420  that is used to compress the refrigerant, R. The compressor  420  in the refrigeration loop  430  can then be used to control the pressure associated with the refrigerant in the refrigeration loop  430 . In other words, the compressor  420  is used to adjust the boiling point of the refrigerant. The compressors  410 ,  420  are used to place both the waste stream and the refrigerant R in a state where the latent heat of transfer can occur for both fluids within the heat transfer device  402 . In the case of a heat exchanger, the latent heat of transfer is occurring for both fluids at a plate or plates within the heat transfer device  402 . When the latent heat of transfer is occurring for a fluid is being transferred at a plate or plates within the heat transfer device  402  the fluid is said to be at a pinch point. The strategic use of liquid de-superheaters in both waste heat stream  460  and refrigerant R 1  streams arc used to further refine the pinch point. The pinch point is a realm where there is sufficient temperature difference to move heat across the plate or plates in the heat transfer device  402 . More specifically, one fluid must be at a state where it can transfer the latent heat and the other fluid must be at a state where it is capable of absorbing the heat given up by the other fluid. In this particular embodiment, the steam in the waste stream  460  must be in a state where it is able to condense and transfer the latent heat to the heat exchanger and the refrigerant R must be in a state where the latent heat can be absorbed by vaporization. This provides for an efficient transfer of heat from the waste stream  460  to the refrigerant  402 . The compressors  410 ,  420  are used to place the two streams, the waste stream  460 , and the refrigerant in the refrigeration loop  430  in a state where the efficient heat transfer can occur in the heat transfer device  402 .  
         [0019]     In one embodiment, the compressors  410 ,  420  are controlled to place the steam from the waste stream  460  at a pinch point and the refrigerant in the refrigeration loop  430  at a pinch point. The pinch points of each fluid are matched to provide for an efficient transfer of heat from the steam from the waste stream  460  to the refrigerant in the refrigeration loop  430 . In one embodiment, the compressors  410  and  420  are dynamically controlled. The condition of the waste stream  460  can change. The compressors are controlled to condition or place the steam from the waste stream  460  in a state where it is ready to release its latent heat, and to condition the refrigerant so that it can absorb the latent heat from the steam of the waste stream  460 . It should also be noted that in some embodiments of the HTBR system, as the temperature-pressure rises in the refrigerant stream, increases in energy efficiency result in the form of lower compressor energy.  
         [0020]      FIG. 5  is a flow chart of a method  500  for controlling the compressors  410 ,  420  of the waste stream  460  and the refrigerant respectively. The waste stream  460  condition is monitored using sensors for temperature and pressure, and the like, as depicted by reference numeral  510 . The refrigerant condition is monitored using sensors for temperature and pressure, and the like, as depicted by reference numeral  512 . The condition of the waste stream  460  is then placed in a state where the latent heat can be freely released (i.e. at the pinch point of the steam in the waste stream  460 ) by varying the pressure in the waste stream  514  using the compressor  410  and modifying the superheat temperature using de-superheaters. At the same time, the refrigerant is then placed in a state where the latent heat from the waste stream  460  can be absorbed by the refrigerant. The pressure on the refrigerant can be varied  516  using the compressor  420  and modifying the refrigerant superheat temperature with de-superheaters. The sensed conditions are continuously monitored using sensors. The data from the sensors is used in a feedback control loop for the condition of the waste stream  460 . Data from sensors sensing the condition of the refrigerant is used in a feedback control loop for the condition of the refrigerant in the refrigeration loop  430 . In one embodiment, a computer  600  controls the compressors  410  and  420  and de-superheaters to keep both the refrigerant and the waste stream  460  in a condition at their respective pinch points to allow for efficient heat transfer. Of course, the transferred heat can be used in other portions of a system.  
         [0021]     In one embodiment of the method  500 , superheat water vapor from a source, such as a superheated drying apparatus, is condensed by an evaporator associated with a high temperature balanced refrigeration device. This heat energy in the form of superheated water and latent heat is transferred to either a refrigerant or condensate from a steam process. In the method  500 , the pinch points are matched by manipulating refrigerant properties or changing pressure in the superheated waste stream to the evaporator. Another embodiment of the method  500  is used in a ethanol plant. In this other embodiment of the method  500 , a distillation condenser is used in place an evaporator of a high temperature balanced refrigeration device as part of a closed loop balanced refrigeration cycle. A pinch effect is made by using the correct azeotrope for the refrigerant thus allowing maximum heat transfer at the condenser and the lowest compression power for one or both of the compressors  410 ,  420 . The higher energy refrigerant is condensed at the distillation reboiler.  
         [0022]     Part of production of ethanol may include cooking of a liquid slurry. Liquid slurry cooking in systems that have matched heat demand (condenser) and cooling (evaporator) loads present another application for a high temperature balanced refrigeration (“HTBR”) system. The energy needed for cooking comes from the slurry cooling section and a compressor raises the temperature to a level to provide the delta temperature needed for the cook. The system is balanced except for superheat at the compressor and system line heat losses.  
         [0023]     Another application for an HTBR system is a molecular sieve. Molecular sieves may be altered to remove the waste heat discharged at the product condenser and by transferring this energy to a properly matched and conditioned refrigerant. The properly matched refrigerant is vaporized in the HTBR system. A compressor is used to increase the energy level to meet the delta temperature for evaporating the fluid to be processed in the molecular sieve.  
         [0024]     Also contemplated is an HTBR system for balancing the energy within an entire ethanol production facility. Such a system includes at least one HTBR loop at the distillation or stripper and rectifier with its concurring superheat gain. The heat from the distillation or stripper and rectifier will substantially supply the energy for the entire process. The entire system is balanced after the ethanol production facility is started up. Energy that here to for has been dumped, if in a latent vapor phase, can be extracted and its value (temperature) raised to provide heat for many industrial and commercial processes with system COP&#39;s of from 3-12:1 ratios. This system, called High Temperature Balanced Refrigeration manipulates vapor pressure in a refrigerant (using various azeotropes) closed loop at much higher temperatures than is standard practice. Heat is transfered from the dumped stream to the refrigerant stream using plate heat exchangers and setting the thermodynamics of each stream to maximize phase change latent heat transfer. The heat energy is then given a higher value via compression to match the need of the industrial process and disbursed via another heat exchanger.  
         [0025]      FIG. 6  is a block diagram of a computer system  2000  that executes programming for performing the above algorithm or method  500  shown in  FIG. 5 . A general computing device in the form of a computer  2010 , may include a processing unit  2002 , memory  2004 , removable storage  2012 , and non-removable storage  2014 . Memory  2004  may include volatile memory  2006  and non-volatile memory  2008 . Computer  2010  may include, or have access to a computing environment that includes, a variety of computer-readable media, such as volatile memory  2006  and non-volatile memory  2008 , removable storage  2012  and non-removable storage  2014 . Computer storage includes random access memory (RAM), read only memory (ROM), erasable programmable read-only memory (EPROM) &amp; electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD ROM), Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium capable of storing computer-readable instructions. Computer  2010  may include or have access to a computing environment that includes input  2016 , output  2018 , and a communication connection  2020 . One of the inputs could be a keyboard, a mouse, or other selection device. The communication connection  2020  can also include a graphical user interface, such as a display. The computer may operate in a networked environment using a communication connection to connect to one or more remote computers. The remote computer may include a personal computer (PC), server, router, network PC, a peer device or other common network node, or the like. The communication connection may include a Local Area Network (LAN), a Wide Area Network (WAN) or other networks.  
         [0026]     Computer-readable instructions stored on a computer-readable medium are executable by the processing unit  2002  of the computer  2010 . A hard drive, CD-ROM, and RAM are some examples of articles including a computer-readable medium. For example, a computer program  2025  capable of providing a generic technique to perform access control check for data access and/or for doing an operation on one of the servers in a component object model (COM) based system according to the teachings of the present invention may be included on a CD-ROM and loaded from the CD-ROM to a hard drive. The computer-readable instructions allow computer system  2000  to provide generic access controls in a COM based computer network system having multiple users and servers.  
         [0027]     A machine-readable medium that provides instructions that, when executed by a machine, cause the machine to perform operations including the controlling of either the entire energy conversion process or various subprocesses associated with the refrigeration device  400 , and more specifically the control of the compressors  410  and  420  for conditioning the waste stream  460  and the refrigerant associated with the refrigeration loop  430  (see  FIG. 4 ).  
         [0028]     The Abstract is provided to comply with 37 C.F.R. §1.72(b) to allow the reader to quickly ascertain the nature and gist of the technical disclosure. The Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.