INDUSTRIAL APPLICATIONS

CROSS-REFERENCE TO RELATED APPLICATION

[01] This application claims priority under 35 U.S.C. § 119(e) to U.S.

provisional application 61/313,517, filed March 12, 2010, the entirety of which is hereby incorporated by reference herein.

BACKGROUND

[02] In industrial processes, process fluids are usually required for adding heat energy in some sub-processes and absorbing heat energy in other sub- processes. Warming process fluid so that it can supply heat energy in sub- processes typically requires natural gas or other independent heat source. Similarly, cooling process fluid so that it can absorb heat energy in sub- processes typically requires some type of independent refrigeration cycle.

[03] Some systems aim to use some of the heat from one process fluid to another in an industrial process without independent heat energy sources or sinks, but such systems use a central energy storage mechanism. One such energy storage mechanism is an energy field. In a typical heat pump application (such as a geothermal heating/ cooling system) the construction of the energy field can exceed 50% of the total project cost. In addition, energy fields require a significant amount of physical space that in many potential applications is simply not available. Furthermore, transferring energy into and out of the centralized storage system itself requires energy reducing the overall system efficiency.

SUMMARY

[04] Embodiments of the present invention permit the transfer of heat

energy from one process fluid to another in an industrial process without the need for an energy field or centralized energy storage. Preferred embodiments include one or more heat transfer modules that draw heat from one process fluid into circulating refrigerant in an evaporator heat exchanger and supply that heat to a different process fluid in a condenser heat exchanger. In some embodiments, adjustments are made to one or more parameters of one or more process fluids to ensure the desired heat transfer is accomplished with the heat transfer module's compressor operating near optimum efficiency.

[05] Heat transfer modules used in connection with the present invention can be self-contained, engineered structures that include pumps, heat exchangers, compressors, instrumentation, valves and a control system in a unitized housing. Heat transfer modules can be deployed for the purpose of energy conservation in commercial, industrial, and utility applications. A common example of a heat transfer module is a heat pump unit. One or more heat transfer modules (and related process equipment) can be engineered, designed, installed, and/or maintained in a commercial, industrial or utility application. BRIEF DESCRIPTION OF FIGURES

[06] The following figures are illustrative of particular embodiments of the present invention and therefore do not limit the scope of the invention. The figures are intended for use in conjunction with the explanations in the following detailed description. Embodiments of the present invention will hereinafter be described in conjunction with the appended photographs, wherein like numerals denote like elements.

[07] FIGS. 1A-1B are schematic diagrams of illustrative systems for

transferring heat energy from a cooling fluid to a warming fluid via a heat transfer module in an industrial application.

[08] FIG. 2 is a schematic diagram of an illustrative system for transferring heat energy from a cooling fluid to a warming fluid via two heat transfer modules in an industrial application.

[09] FIG. 3 is a schematic diagram of an illustrative system for transferring heat energy from a cooling fluid to two warming fluids via two heat transfer modules in an industrial application. [10] FIG. 4 is a schematic diagram of an illustrative system for using a heat transfer module to reduce the volume of water handled by a cooling tower, [n] FIG. 5 is a schematic diagram of an illustrative system for using heat transfer modules to draw heat from cooling water and to warm ambient air in preparation for drying distilled grain in an ethanol production facility.

[12] FIG. 6 is a schematic diagram of an illustrative system for using heat transfer modules to draw heat from cooling water and to regulate flow properties of water passing from a scrubber to a subsequent process in an ethanol production facility.

[13] FIG. 7 is a schematic diagram of an illustrative system for using heat transfer modules to draw heat from cooling water and well water and to warm water before it enters a cook system in an ethanol production facility.

[14] FIG. 8 is a schematic diagram of an illustrative system for using heat transfer modules to draw heat from cooling water and to warm well water before it is used for various purposes in an ethanol production facility, thereby off-loading downstream heating requirements that would otherwise be achieved with traditional heating systems (e.g., steam boilers).

[15] FIG. 9A is a perspective view of an illustrative liquid-to-vapor/gas heat transfer module according to some embodiments of the present invention.

[16] FIG. 9B is a perspective view of an illustrative liquid-to-liquid heat transfer module according to some embodiments of the present invention.

[17] FIG. 10 is a schematic diagram of an illustrative system for controlling various components of a heat transfer module.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[18] The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides practical illustrations for implementing exemplary embodiments of the present invention. Examples of constructions, materials, dimensions, and manufacturing processes are provided for selected elements, and all other elements employ that which is known to those of skill in the field of the invention. Those skilled in the art will recognize that many of the examples provided have suitable alternatives that can be utilized.

[19] FIGS. 1A-1B show systems for using a heat transfer module 2 in an

industrial process to remove heat from a cooling fluid and provide heat to a warming fluid. The heat transfer module 2 can include a compressor 6, a condenser heat exchanger 8, an expansion valve 10, and an evaporator heat exchanger 4. Refrigerant circulates through the heat transfer module 2, getting warmer as it passes through the compressor 6 toward the condenser heat exchanger 8, shedding heat in the condenser heat exchanger 8, getting cooler as it passes through the expansion valve 10 toward the evaporator heat exchanger 4, taking on heat in the evaporator heat exchanger 4, and cycling back through the compressor 6.

[20] The refrigerant typically sheds heat to one fluid (e.g., liquid, vapor, gas, etc.) in the condenser heat exchanger 8 and takes on heat from a different fluid in the evaporator heat exchanger 4. As shown in FIGS. 1A-1B, the refrigerant circulating through the heat transfer module 2 can take on heat from a fluid flowing toward a cooling industrial sub-process in the evaporator heat exchanger 4. One example of cooling industrial sub-process is condensing unwanted components out of vapor/gas streams (e.g., scrubbing pollutants out of an industrial waste stream). Another common example of a cooling industrial sub-process is removing heat from industrial equipment (e.g., a fermentation vessel in an ethanol production process). Other examples of cooling industrial sub-processes come from the food processing industry, such as cooling cans in a large-scale vegetable canning plant to ambient temperature after the food inside has been cooked and/or pasteurized or freezing prepared food after it has been cooked and packaged. Embodiments of the present invention work with and enhance many kinds of cooling industrial sub- processes. In some systems, the cooling fluid enters the evaporator heat exchanger 4 from a previous industrial sub-process. In some systems, the cooling fluid enters the evaporator heat exchanger 4 from a fluid source (e.g., a well).

[21] FIGS. 1A-1B also shows that the refrigerant circulating through the heat transfer module 2 can shed heat to a fluid flowing toward a warming industrial sub-process in the condenser heat exchanger 8, like a conventional heat pump. In this way, heat from the cooling fluid can be transferred to the warming fluid through the refrigerant via the evaporator heat exchanger 4 and the condenser heat exchanger 8. One example of a warming industrial sub-processes is drying elements being processed (e.g., distilled grain in an ethanol production process). Another example is heating various processing equipment (e.g., equipment for warming cold corn flour during winter months leading to the slurry system where hot water is added). Another common example is preheating fluids before they enter processing vessels, such as warming water before it enters an ethanol cook system, pre-warming cold influent well water prior to process systems requiring heat for process effect, warming well water to propagate yeast, and so on. In some systems, the warming fluid enters the condenser heat exchanger 8 from a previous industrial sub-process. In some systems, the warming fluid enters the condenser heat exchanger 8 from a fluid source (e.g., ambient air). The warming fluid can enter the condenser heat exchanger 8 from a fluid source and the cooling fluid can enter the evaporator heat exchanger 4 from a previous industrial sub-process, or the warming fluid can enter the condenser heat exchanger 8 from a previous industrial sub- process and the cooling fluid can enter the evaporator heat exchanger 4 from a fluid source— many combinations are possible.

[22] Heat transfer modules according to embodiments of the present

invention that are used in industrial applications can have important differences from heat pumps used in HVAC applications. One key difference relates to how the two heat transfer modules are controlled. In HVAC applications, precise input and output parameters (e.g., temperature, flow rate, etc.) are generally less important than in industrial applications. Heat transfer modules for HVAC applications specifically endeavor to provide a heating or cooling effect for ambient conditioning. Minor variations in HVAC fluid parameters tend to have little effect on the overall comfort of the conditioned space. Moreover, because noticeable changes in the overall comfort of the conditioned space tend to occur slowly, heat transfer module operation adjustments can usually be made quickly enough to prevent any discomfort in the conditioned space. In contrast, if the heat transfer module does not precisely control warming/cooling fluid parameters in industrial applications, significant downstream consequences can result. Additionally, in HVAC applications, if the heat transfer module is cooling the conditioned space, what happens to the heat drawn out of the space is typically of little concern.

Likewise, if the heat transfer module is heating the conditioned space, the effect on the environment from which the heat is drawn is typically of little concern. In contrast, when heat transfer module embodiments according to the present invention are used in industrial applications, they must usually be controlled to account for both the cooling fluid parameters and the warming fluid parameters because the fluids will be used in separate industrial sub- processes. For these and other reasons, precise control of fluid parameters is of greater importance for industrial heat transfer modules according to embodiments of the present invention than for HVAC heat transfer modules. Another key difference between heat transfer modules used in HVAC applications and heat transfer modules according to embodiments of the present invention that are used in industrial applications is that the metallurgy of one or more of the heat exchangers 4, 8 must often be modified to accommodate cooling or warming fluids in industrial applications because chemicals in the cooling or warming fluids may erode heat exchangers in standard heat transfer modules.

[23] Although heat pump units are perhaps the most common heat transfer module used in connection with the present invention, other heat transfer modules can be used. For example, a reverse-acting screw compressor can replace an expansion valve in some embodiments. Such a compressor can be configured to achieve the same degree of expansion as would be achieved by the expansion valve. An advantage of this configuration, however, is that the reverse-acting screw compressor is able to convert the refrigerant expansion into mechanical energy. Such mechanical energy can be used to turn a generator, drive a pump, compress air, and so on. Other heat transfer modules, with different configurations of pumps, heat exchangers,

compressors, instrumentation, valves, and/or controllers, can be used, depending on the type of industrial process and a variety of other factors.

[24] As can be seen, the systems of FIGS. 1A-1B lack an energy field or

centralized energy storage. The illustrated systems do not need to store heat energy. Such systems use modulating/digital heat transfer modules (or multiple heat transfer modules used in parallel— see, e.g., FIGS. 5-8), along with the application of industrial control methods that process multiple inputs and derive multiple outputs with high levels of speed and accuracy (discussed in greater detail in connection with FIG. 10). In this way, the systems can monitor the energy needs of both the heating and cooling processes

simultaneously and modulate the BTU output of the system to match the output to the smaller energy need. For example, suppose the cooling industrial sub-process involved shedding X BTUs to the cooling fluid and the yet-to-be- cooled cooling fluid was suited to take on only 0.75X BTUs. Assuming a constant cooling fluid flow rate, that would mean that the cooling fluid would have to shed 0.25X BTUs either to the heat transfer module refrigerant or to other cooling means (e.g., a cooling tower) before entering the cooling industrial sub-process. Suppose also that the warming industrial sub-process involved taking on 2X BTUs from the warming fluid and the yet-to-be-warmed warming fluid was suited to provide only 1.25X BTUs. Again, assuming a constant warming fluid flow rate, that would mean that the warming fluid would have to take on 0.75X BTUs either from the heat transfer module refrigerant or from other warming means (e.g., a steam boiler). In this scenario, the cooling fluid would shed 0.25X BTUs to the heat transfer module refrigerant, which would then be provided to the warming fluid. That would mean that the warming fluid would have to take on 0.5X BTUs from other warming means. This results in no excess energy being generated that would require storage in a centralized energy field. With this system 100% of the heat energy that is drawn into the refrigerant in the evaporator heat exchanger 4 is shed from the refrigerant in the condenser heat exchanger 8 to the warming fluid.

[25] As noted above, eliminating the need for an energy field or centralized energy storage can provide several advantages. In a typical heat transfer module application (such as a geothermal heating/cooling system) the construction of the energy field can exceed 50% of the total project cost. In addition energy fields require a significant amount of physical space that in many potential applications is simply not available. Furthermore, transferring energy into and out of the centralized storage system itself requires energy reducing the overall system efficiency. Transferring heat energy from the cooling fluid to the warming fluid by way of the heat transfer module can result in very significant efficiency improvements.

[26] FIGS. 2-3 show systems for using two heat transfer modules 2, 12 in an industrial process to remove heat from a cooling fluid and provide heat to a warming fluid. Like the first heat transfer module 2, the second heat transfer module 12 can include a compressor 16, a condenser heat exchanger 18, an expansion valve 20, and an evaporator heat exchanger 14. The second heat transfer module 12 can function like the first heat transfer module 2. In many embodiments, cooling fluid can pass from a previous industrial sub-process or a fluid source through the first and second heat transfer modules 2, 12 in parallel, with both heat transfer modules 2, 12 operating at the same or similar parameters. In some embodiments, the cooling fluid can pass from a previous industrial sub-process or a fluid source through the first and second heat transfer modules 2, 12 in series, with the first heat transfer module 2 extracting one quantity of heat from the cooling fluid and the second heat transfer module 12 extracting another quantity of heat from the cooling fluid. In many embodiments, warming fluid can pass from a previous industrial sub-process or a fluid source through the first and second heat transfer modules 2, 12 in parallel, with both heat transfer modules 2, 12 operating at the same or similar parameters. In some embodiments, the warming fluid can pass from a previous industrial sub-process or a fluid source through the first and second heat transfer modules 2, 12 in series, with the first heat transfer module 2 providing one quantity of heat to the warming fluid and the second heat transfer module 12 providing another quantity of heat to the warming fluid.] The first and second heat transfer modules 2, 12 can receive warming and/or cooling fluids from the same or different sources and can provide warming and/or cooling fluids to the same or different industrial sub- processes. In FIGS. 2-3, the first and second heat transfer modules 2, 12 receive cooling fluid from a previous industrial sub-process and provide cooling fluid to a first cooling industrial sub-process. In some systems, the first and second heat transfer modules 2, 12 can receive cooling fluid from two different sources and provide cooling fluid to the first cooling industrial sub- process. In some systems, the first and second heat transfer modules 2, 12 can receive cooling fluid from two different sources and provide cooling fluid to two different cooling industrial sub-processes. In some systems, the first and second heat transfer modules 2, 12 can receive cooling fluid from a common source and provide cooling fluid to two different cooling industrial sub- processes. In FIG. 2, the first and second heat transfer modules 2, 12 receive warming fluid from a previous industrial sub-process and provide warming fluid to a first warming industrial sub-process. In some systems, the first and second heat transfer modules 2, 12 can receive warming fluid from two different sources and provide warming fluid to the first warming industrial sub-process. In FIG. 3, the first and second heat transfer modules 2, 12 receive warming fluid from two different sources (the first heat transfer module 2 from a fluid source and the second heat transfer module 12 from a previous industrial sub-process) and provide warming fluid to two different warming industrial sub-processes (the first heat transfer module 2 to a first warming industrial sub-process and the second heat transfer module 12 to a second warming industrial sub-process). In some systems, the first and second heat transfer modules 2, 12 can receive warming fluid from a common source and provide warming fluid to two different warming industrial sub-processes. Many combinations of input and output cooling/warming fluids are possible.

[28] Many systems employ more than two heat transfer modules. In some systems, three, four, five, or more heat transfer modules can be employed. In such systems, some or all of the heat transfer modules can receive cooling fluid from the same source. In such systems, some or all of the heat transfer modules can receive warming fluid from the same source. In such systems, some or all of the heat transfer modules can provide cooling fluid to the same cooling industrial sub-process. In such systems, some or all of the heat transfer modules can provide warming fluid to the same warming industrial sub-process. In such systems, the various heat transfer modules can receive warming and/or cooling fluids from multiple sources. In such systems, the various heat transfer modules can provide warming and/or cooling fluids to multiple industrial sub-processes. Again, many combinations of input and output cooling/warming fluids are possible for systems employing multiple heat transfer modules.

[29] FIG. 4 shows a system for minimizing an amount of water that is cooled via a cooling tower in an industrial process. One drawback to cooling water (or other fluids) via a cooling tower is that significant quantities of water are lost due to evaporation. The volume of water that exits the cooling tower can be less than the volume of water that enters the cooling tower because of evaporative loss. Over time, these losses add up to volumes of water that are quite substantial. Additionally, water must be added to the system to compensate for these losses, meaning that the cooling system is not a closed- loop system. Another issue involves the chemicals that are often added to the water to treat for corrosion, iron, contaminants, etc. When the water evaporates, these chemicals are also lost. Thus, it is desirable to bypass the cooling tower with as much water as possible, cooling it instead with

alternative equipment. [30] In the system of FIG. 4, some of the water that would otherwise be cooled with the cooling tower is diverted into the first heat transfer module 2 from a return line flowing toward the cooling tower from an industrial heat exchanger. The water in the return line is warmer than the water in the supply line because the water takes on heat from the industrial equipment being cooled by the industrial heat exchanger. The quantity of water that is diverted from the return line can be circulated through the evaporator heat exchanger 4, where the water can shed heat to the heat transfer module refrigerant. The water can then be introduced back into the supply line flowing from the cooling tower toward the industrial heat exchanger. In many systems, the water exiting the evaporator heat exchanger 4 is at a lower temperature than the water in the supply line. This can also reduce the total water quantity required to cool the relevant industrial equipment, as colder supply line water means that less supply line volume is required to accomplish the same cooling. In many embodiments, return line water is diverted through multiple heat transfer modules (in parallel and/or in series) to accomplish cooling other than through the cooling tower. In some embodiments, the cooling tower can be entirely replaced by several heat transfer modules operating as described herein.

[31] Bypassing the cooling tower, as shown in FIG. 4, can be incorporated into many systems with a variety of different characteristics. As shown in FIG. 4, warming fluid can be circulated through the condenser heat exchanger 8 of the heat transfer module 2 according to any of the manners discussed herein. In this way, heat that the cooling fluid took on at the industrial heat exchanger can be transferred to the warming fluid through the heat transfer module refrigerant via the evaporator heat exchanger 4 and the condenser heat exchanger 8.

[32] Heat transfer modules discussed herein can be configured to work with a variety of cooling fluids and a variety of heating fluids. Some preferred heat transfer modules are configured to accommodate cooling fluid and warming fluid that are both liquid. Such heat transfer modules are often called liquid- to-liquid heat transfer modules. Examples include water-to-water, and so on. One example of a liquid-to-liquid heat transfer module is shown in FIG. 9B. Some preferred heat transfer modules are configured to accommodate cooling fluid that is liquid and warming fluid that is vapor/gas. Such heat transfer modules are often called liquid-to-gas heat transfer modules. Examples include water-to-air, water-to-vapor, and so on. One example of a liquid-to- liquid heat transfer module is shown in FIG. 9A. Some heat transfer modules are configured to accommodate cooling fluid that is vapor/gas and warming fluid that is liquid. Some heat transfer modules are configured to

accommodate cooling fluid that is vapor/gas and warming fluid that is vapor/gas. Other combinations of cooling fluids and warming fluids can be accommodated by heat transfer modules according to embodiments of the present invention.

[33] FIGS 5-8 show illustrative systems according to embodiments of the present invention for use in ethanol production facilities. The illustrative heat transfer modules shown in FIGS. 5-8 include liquid-to-air modulating heat transfer modules 102, liquid-to-liquid modulating heat transfer modules 104, and liquid-to-liquid two stage heat transfer modules 104'. Ethanol production facilities, or ethanol plants, involve several cooling sub-processes and several warming sub-processes in which fluids carry away or deliver heat. Often, fluids used in an ethanol production facility carry away heat and simply dispense it into the atmosphere. The heat is not recycled for other uses.

Similarly, heating fluids in ethanol production facilities (e.g., via steam boilers, hot water boilers, direct-fired burners, exothermic processes such as

fermentation, etc.) typically consumes large amounts of energy. Thus, because many embodiments of the present invention involve recycling waste heat energy for use in warming sub-processes, such embodiments of the present invention can provide very significant energy savings for ethanol production facilities.

[34] Additionally, and perhaps more importantly, embodiments of the

present invention can substantially reduce the volume of water consumed in a conventional ethanol production facility. As is discussed in greater detail below, a fermentation vessel in an ethanol production facility produces large quantities of heat and is the subject of significant cooling efforts. If the fermentation vessel is not cooled properly, the performance of the

fermentation enzymes is inhibited. In conventional ethanol plants, very large volumes of cooling water are circulated through a loop that includes a cooling tower and a fermentation vessel heat exchanger. The water draws in heat energy in the fermentation vessel heat exchanger and sheds that heat in the cooling tower. But as is mentioned above, considerable quantities of water are lost in cooling towers due to evaporation. In some systems, the volume of water flowing into the cooling tower is up to 1.3% greater than the volume of water flowing out of the cooling tower. While this may not sound like a large loss, when one considers that the average dry mill ethanol plant can have a flow rate of 55,000 gpm, small losses can add up quickly.

[35] Additionally, reducing the evaporative loss at the cooling tower can have a cascading effect on water use throughout the ethanol production facility. The water that is lost through evaporation has to be "made-up" by supplying more water into the system. These additional quantities of water must be treated, filtered, softened, and otherwise conditioned to make them suitable for use in the process. Treatment methods for water entering a process plant can include:

• Chemical treatment systems which require the purchase of various chemical agents to neutralize undesired water properties

• Filtration systems such as water softening, media filters, and reverse osmosis systems. These system require regeneration cycles and may still require chemical use (e.g., water softeners may utilize a sodium based brine as a regeneration agent). The regeneration water is typically discharged from the plant.

These illustrative treatment processes not only increase water use for the regeneration cycle, they also require that the regenerated water be discharged from the plant. The cascading effect of reducing evaporative loss dramatically reduces the plant discharge as well. The design parameters of a system capable of delivering 3.19 million BTUs of cooling at an ethanol facility would result in up to 309 million gallons of water bypassing the cooling tower each year. The cascading effect of eliminating the evaporative loss of this water will reduce well water use by over 10 million gallons annually and will reduce the facilities discharge by over 6.5 million gallons annually.

[36] Thus, because many embodiments of the present invention involve cooling quantities of water with heat transfer modules, thereby bypassing the cooling tower and its associated evaporative loss, such embodiments of the present invention can provide very significant water savings for ethanol production facilities.

[37] In the systems shown in FIGS. 5-8, the heat transfer modules can, if desired, be removed or isolated from the other components of the system. Valves can be adjusted to temporarily or permanently channel fluid to where it would be channeled in the absence of any heat transfer modules. None of the existing equipment need be modified in order to install the heat transfer modules. This can be useful if one or more of the heat transfer modules is in need of repair or if a decision is made to eliminate the heat transfer modules from the industrial process altogether. For example, valves can be adjusted to stop diverting water from the cooling tower return line to the heat transfer modules, allowing instead all of the water to pass through the cooling tower. In another example, valves can be adjusted to stop channeling water that exits the carbon dioxide scrubber to the heat transfer modules, allowing instead all of the water to pass directly to the cook system. This feature, which can be referred to as the heat transfer modules' "bolt-on" capability, can be useful in many ethanol-related applications as well other industrial applications. In this way, going back to the system as it existed prior to the addition of the heat transfer modules can be accomplished with relative ease.

[38] In many of the systems discussed herein, cooling fluid bound for a

cooling industrial sub-process is routed directly through the evaporator heat exchanger of a heat transfer module, or warming fluid bound for a warming industrial sub-process is routed directly through the condenser heat exchanger of a heat transfer module. In many systems, however, the cooling/warming fluid need not be routed directly through the relevant heat exchanger of the heat transfer module. Instead, the cooling/warming fluid can be routed through a separate heat exchanger in which the cooling/warming fluid sheds/draws heat energy from a fluid that is in thermal communication with the relevant heat exchanger of the heat transfer module.

[39] FIG. 10 shows an illustrative system for transferring energy from one process fluid to another in an industrial process. The system can include a heat transfer module 202, such as those discussed elsewhere herein, with a compressor 206, a condenser heat exchanger 208, an expansion valve 210, and an evaporator heat exchanger 204. A cooling fluid can enter the evaporator heat exchanger 204, where it can shed heat energy to refrigerant flowing through the heat transfer module 202. The refrigerant can transfer that heat energy to a warming fluid in the condenser heat exchanger 208, thereby eliminating any need for central energy storage. It should be understood that systems incorporating concepts illustrated in FIG. 10 can be used in many settings other than industrial processes, such as the following:

• District Heating and Cooling Plants

• Commercial Laundry Facilities

• Central Plant Heating and Cooling Systems

> Hotels/Resorts

> Hospitals

> Institutional Facilities (Schools, Universities, Prisons)

• Dehumidification Systems

> Ice Arena

> Indoor Swimming Pool Areas

> Indoor Water Parks

• Merchant Power Utility

[40] The system can include a heat transfer module refrigerant sensing

mechanism that senses various attributes of the refrigerant during operation of the heat transfer module 202. The refrigerant sensing mechanism of FIG. 10 includes a suction pressure sensor 212, which can be configured to regularly measure a suction pressure value for the compressor 206 during operation of the heat transfer module 202. The refrigerant sensing mechanism of FIG. 10 further includes a discharge pressure sensor 214, which can be configured to regularly measure a discharge pressure value for the compressor 206 during operation of the heat transfer module 202. The refrigerant sensing mechanism of FIG. 10 further includes a suction temperature sensor 216 and a discharge temperature sensor 218, which can be configured to regularly measure a suction temperature value and a discharge temperature value, respectively, during operation of the heat transfer module 202. Various other sensors, aimed at sensing various attributes of the refrigerant, can be incorporated into embodiments of the refrigerant sensing mechanism.

[41] In preferred embodiments, the system can include a compressor

controller 220 configured to ensure that the compressor 206 operates at as close to optimum efficiency as possible. When compressors operate near optimum efficiency, less energy input is required, and the compressors last longer and require less maintenance. In some embodiments, a key component in ensuring that the compressor 206 operates near optimum efficiency is the pressure differential of the refrigerant across the compressor 206 (i.e., the discharge pressure minus the suction pressure). If that pressure differential is too low or too high, the compressor 206 does not operate as efficiently and is at increased risk of breaking down. Based upon the application in which the compressor is applied, the compressor will have a "sweet spot" pressure differential range within which it operates most efficiently, and the compressor controller 220 aims to keep the compressor 206 within that range. The compressor controller 220 can be configured to receive the suction pressure value and the discharge pressure value from the refrigerant sensing

mechanism. With that information, the compressor controller 220 can be configured to compare the suction pressure value to the discharge pressure value to determine an operational pressure differential. [42] As noted, the compressor controller 220 can be configured to maintain the operational pressure differential within a predetermined range. If the operational pressure differential is too high, the compressor controller 220 can take steps to reduce it. If the operational pressure differential is too low, the compressor controller 220 can take steps to increase it. The compressor controller 220 can take such steps by causing one or more of several variables to be adjusted. In some embodiments, the compressor controller 220 can cause the temperature and/or pressure and/or flow rate of a cooling fluid entering the evaporator heat exchanger 204 to be adjusted. In some

embodiments, the compressor controller 220 can cause the temperature and/or pressure and/or flow rate of a warming fluid entering the condenser heat exchanger 208 to be adjusted. Some illustrative ways of causing such adjustments are discussed below.

[43] The system of FIG. 10 includes a cooling fluid controller 222 and a

warming fluid controller 224. Some systems can include only one or the other. The compressor controller 220 can be configured to cause the pressure and/or the flow rate of the cooling fluid to be adjusted by communicating instructions to the cooling fluid controller 222. The cooling fluid controller 222 can be configured to cause adjustment to a cooling fluid inlet pump 226. The compressor controller 220 can be configured to cause the pressure and/or the flow rate of the warming fluid to be adjusted by communicating instructions to the warming fluid controller 224. The warming fluid controller 224 can be configured to cause adjustment to a warming fluid inlet pump 228. As is discussed in greater detail below, there are several advantages to being able to adjust different parameters of different process fluids in different applications.

[44] In systems that involve a compressor controller 220, a warming fluid controller 224, and a cooling fluid controller 222, the three controllers can be programmed to limit the speed at which the output value adjusts. If the output values are all adjusted at the same rate of speed, each controller may seek to make adjustments on an almost continuous basis, never allowing the system to reach any kind of steady state. Cascading the controllers, or setting them to - l8 - adjust their outputs at different rates of speed allows the lagging (slower- acting) controllers to react to adjustments made by the leading (faster-acting) controllers. For example, in preferred embodiments, one of the warming fluid controller 224 or the cooling fluid controller 222 can be configured to cause adjustment to the warming fluid inlet pump 228 or the cooling fluid inlet pump 226, respectively, at a first rate of speed (e.g., the output can adjust 1% in one second). The other of the warming fluid controller 224 or the cooling fluid controller 222 can be configured to cause adjustment to the warming fluid inlet pump 228 or the cooling fluid inlet pump 226, respectively, at a second rate of speed (e.g., the output can adjust 1% in two seconds), which is slower than the first rate of speed. The compressor controller 220 can be configured to communicate instructions to the warming fluid controller 224 and/or the cooling fluid controller 222 at a third rate of speed (e.g., the output can adjust 1% in three seconds), which is slower than the second rate of speed. It should be understood that other configurations may be employed for other systems and/or different controllers.

[45] As noted, in some embodiments, the compressor controller 220 can be configured to cause the temperature of the cooling fluid and/or the

temperature of the warming fluid to be adjusted. In many such embodiments, the cooling fluid inlet pump 226 and the warming fluid inlet pump 228 may have little or no ability to adjust the temperature of the respective fluids. In such embodiments, adjustments to the temperature can be made upstream of the fluid inlet pumps. The compressor controller 220 can be configured to cause the temperature of the cooling fluid and/or the temperature of the warming fluid to be adjusted by communicating instructions to one or more facility process controllers 230, 232. The facility process controllers 230, 232 can be responsible for controlling one or more processes at a facility into which one or more heat transfer modules are incorporated. In preferred

embodiments, the facility process controllers 230, 232 can be configured to cause adjustment to one or more portions of the industrial process, thereby adjusting the temperature of the respective fluids before the reach the fluid inlet pumps.

[46] Systems discussed herein that permit selective adjustment of the

temperature and/or pressure and/or flow rate of one or more process fluids can provide a variety of advantages. For instance, such a system can account for situations in which one or more parameters of an input process fluid are dictated by the process itself and are not adjustable. For example, if the flow rate of the cooling fluid is fixed, the temperature and/or pressure of the cooling fluid can be adjusted in order to maintain the desired outputs. If the flow rate of the warming fluid is fixed, the temperature and/or pressure of the warming fluid can be adjusted in order to maintain the desired outputs. In addition, if both the cooling and warming fluid flow rates are fixed, the facility process controllers can be deployed to adjust to the desired outputs. In some embodiments, such selective adjustment can be an important factor in eliminating the need for central energy storage. Such selective adjustment can allow the ability to maintain process set point targets on both the warming fluid and cooling fluid sides of the system, as opposed to just one side or the other. Many systems such as those discussed herein allow optimization of energy consumption, with more performance output being provided per unit of energy input. Selective adjustment of multiple process fluid parameters can further enable the system to operate across the entire range of the performance window of the refrigerant, as opposed to using only part of the refrigerant performance range.

[47] In a first aspect, the present invention involves a method of heating and cooling fluids for use in an industrial process. The method can include providing a heat transfer module that includes a condenser heat exchanger and a evaporator heat exchanger. The method can include circulating a refrigerant through the heat transfer module. The method can include circulating a cooling fluid through the evaporator heat exchanger, thereby removing heat from the cooling fluid and preparing the cooling fluid for a cooling industrial sub-process. The method can include circulating a warming fluid through the condenser heat exchanger, thereby adding heat to the warming fluid and preparing the warming fluid for a warming industrial sub-process. The method can include supplying the cooling fluid from an outlet of the evaporator heat exchanger to equipment for performing the cooling industrial sub-process. The method can include supplying the warming fluid from an outlet of the condenser heat exchanger to equipment for performing the warming industrial sub-process.

[48] As alluded to elsewhere herein, the method of the first aspect can be used in connection with a variety of warming and cooling industrial sub- processes. For example, the cooling industrial sub-process can include (a) scrubbing carbon dioxide out of a fermentation vessel's waste stream in an ethanol production process; (b) cooling a fermentation vessel; (c) a food- related process; or (d) other cooling industrial sub-process. Also, for example, the warming industrial sub-process can include (a) warming water before it enters an ethanol cook system; (b) drying distilled grain in a dryer; or (c) other warming industrial sub-process.

[49] In a second aspect, the present invention involves a method of

transferring energy from one sub-process to another in an industrial process. The method can include providing a heat transfer module that includes a condenser heat exchanger and a evaporator heat exchanger. The method can include circulating a refrigerant through the heat transfer module. The method can include transferring energy (i) from a cooling fluid flowing toward a cooling industrial sub-process (ii) through the refrigerant via the evaporator heat exchanger and the condenser heat exchanger (iii) to a warming fluid flowing toward a warming industrial sub-process.

[50] As alluded to elsewhere herein, the method of the second aspect can be used in connection with a variety of warming and cooling industrial sub- processes. For example, the cooling industrial sub-process can include (a) scrubbing carbon dioxide out of a fermentation vessel's waste stream in an ethanol production process; (b) cooling a fermentation vessel; (c) a food- related process; or (d) other cooling industrial sub-process. Also, for example, the warming industrial sub-process can include (a) warming water before it enters an ethanol cook system; (b) drying distilled grain in a dryer; or (c) other warming industrial sub-process.

[51] In a third aspect, the present invention involves a method of minimizing an amount of water that is cooled via a cooling tower in an industrial process. The method can include providing a heat transfer module that includes a condenser heat exchanger and a evaporator heat exchanger. The method can include circulating a refrigerant through the heat transfer module. The method can include diverting a water quantity from a return line flowing toward the cooling tower from an industrial heat exchanger, the water quantity having been warmed in the industrial heat exchanger. The method can include circulating the water quantity through the evaporator heat exchanger, thereby removing heat from the water quantity and preparing the water quantity to return to the industrial heat exchanger. The method can include introducing the water quantity into a supply line flowing from the cooling tower toward the industrial heat exchanger, thereby bypassing the cooling tower. In some embodiments, circulating the first water quantity through the evaporator heat exchanger further includes transferring heat (i) from the water quantity (ii) through the refrigerant via the evaporator heat exchanger and the condenser heat exchanger (iii) to a warming fluid flowing toward a warming industrial sub-process. In some embodiments, the industrial heat exchanger comprises a fermentation vessel heat exchanger. Methods in accordance with this aspect of the invention can incorporate any of the features discussed elsewhere herein.

[52] In the foregoing detailed description, the invention has been described with reference to specific embodiments. However, it may be appreciated that various modifications and changes can be made without departing from the scope of the invention. Thus, some of the features of preferred embodiments described herein are not necessarily included in preferred embodiments of the invention which are intended for alternative uses.