SYSTEMS AND METHODS FOR A HIGH TEMPERATURE HEAT PUMP

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. Provisional Application No. 63/649,951 titled “High Temperature Heat Pump Design” and filed May 21, 2024 which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to the field of turbomachinery design, compressor design and heat pump technology and, more particularly to systems and methods for delivering heat using a high temperature heat pump apparatus.

BACKGROUND

Heat pump technology can refer to electrically driven vapor compression systems for heating and cooling applications. Many variations of heat pump technology are known, where the underlying thermodynamics of this technology can be similar to heat engines. Various heat pump configurations are commercially available for use in residential, commercial and industrial heating applications. Conventional heat pumps systems may not be effective enough to compete with heating technology, such as natural gas fired boilers, due to the complexity of their design. Furthermore, conventional heat pumps may not have an acceptable heat conversion efficiency to compete with natural gas as a source of heating technology.

The foregoing discussion, including the description of motivations for some embodiments of the invention, is intended to assist the reader in understanding the present disclosure, is not admitted to be prior art, and does not in any way limit the scope of any of the claims.

SUMMARY

A high temperature heat pump apparatus is presented. The apparatus can include a first compression stage including a first evaporator that evaporates a first working fluid to form a first vapor, a first compressor that compresses the first vapor to increase the pressure of the first vapor, and a condenser that condenses the first vapor having increased pressure to deliver heat. The apparatus can include a second compression stage including an second evaporator that evaporates a second working fluid using the heat from the condenser of the first compression stage, where the second evaporator evaporates the second working fluid to form a second vapor, and a second compressor that compresses the second vapor to deliver high temperature heat.

Various embodiments of the apparatus can include one or more of the following features.

In some embodiments, the first working fluid and the second working fluid can include water. In some examples, the first working fluid can include a different fluid from the second working fluid. The high temperature heat can include temperatures in a range of 120 to 280 degrees-C. The first compressor includes a plurality of compressors connected in series or parallel. The plurality of compressors can be connected with at least one of rigid piping or flexible hoses. The apparatus can include an intercooler that cools the first working fluid before entering at least one compressor of the plurality of compressors. The intercooler can inject high-pressure liquid droplets into at least one compressor of the plurality of compressors. The intercooler can inject high-pressure liquid droplets through a nozzle of an impeller of the first compression stage. The second compressor can include a plurality of compressors connected in series or parallel.

A method for delivering heat using a high temperature heat pump apparatus is presented. The method can include evaporating, using a first evaporator, a first working fluid to form a first vapor. The method can include compressing, using a first compressor, the first vapor evaporated in the evaporator to increase the pressure of the first vapor. The method can include condensing, using a condenser, the first vapor having increased pressure to deliver heat. The method can include evaporating, using a second evaporator, a second working fluid using the heat from the condenser to form a second vapor. The method can include compressing, using a second compressor, the second vapor to deliver high temperature heat.

Various embodiments of the method can include one or more of the following steps.

In some embodiments, compressing the first vapor can include compressing using the first compressor having a plurality of compressors. In some examples, the method can include intercooling, using an intercooler, the first working fluid before entering at least one compressor of the plurality of compressors. Intercooling the first working fluid can include injecting high-pressure liquid droplets into the least one compressor of the plurality of compressors. Injecting high-pressure liquid droplets can include injecting high-pressure liquid droplets through a nozzle of an impeller. Injecting high-pressure liquid droplets can include injecting high-pressure liquid through at least one of a restricted orifice or nozzle. Compressing the second vapor can include compressing using the second compressor having a plurality of compressors. Similar to that describe above, the first working fluid and the second working fluid can include water. In some examples, the first working fluid can include a different fluid from the second working fluid. The high temperature heat can include temperatures in a range of 120 to 280 degrees-C.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, which are included as part of the present specification, illustrate the presently preferred embodiments and together with the generally description given above and the detailed description of the preferred embodiments given below serve to explain and teach the principles described herein. Furthermore, like reference numbers refer to similar or the same components within the figures.

FIG. 1 illustrates an exemplary classification of heat pump systems, according to some embodiments.

FIG. 2 illustrates a pressure enthalpy diagram, according to some embodiments.

FIG. 3 illustrates a block diagram of a heat pump system, according to some embodiments.

FIG. 4 illustrates a block diagram of an internally cooled multi-stage mechanical vapor recompression (MVR) system, according to some embodiments.

FIG. 5 illustrates a flowchart of a method for delivering heat using a high temperature heat pump apparatus, according to some embodiments.

FIG. 6 illustrates a compressor stage diagram, according to some embodiments.

FIG. 7 illustrates impeller diagrams for five compressor stages, according to some embodiments.

FIG. 8 illustrates an exemplary radial compressor impeller, according to some embodiments.

FIG. 9 illustrates a diagram of an exemplary hardware and software systems implementing the systems and methods described herein, according to some embodiments.

While the present disclosure is subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The present disclosure should be understood to not be limited to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

DETAILED DESCRIPTION

The present disclosure generally relates to systems and methods for delivering heat using a high temperature heat pump apparatus.

Heat pump technology includes electrically driven vapor compression systems used for heating and/or cooling applications. For example, conventional heat pump devices are widely used in heating and/or cooling residential homes, commercial spaces, and industrial structures. FIG. 1 provides an exemplary overview and classification of heat pump systems.

Overview of Heat Pump Technology

Referring to FIG. 1, an exemplary classification of heat pump systems is shown, according to some embodiments. In some examples, heat pump configurations can be classified 100 into open systems 104 and closed systems 106, as shown. The open systems 104 can be referred to as open cycle systems and the closed systems 106 can be referred to as closed cycle systems. The term cycle can refer to a heating and/or cooling cycle. The open systems 104 can include mechanical vapor recompression systems 108 and thermal vapor recompression systems 110. The closed systems 106 can include compression heat pump systems 112 and sorption systems 114.

Among the heat pump systems 102 shown in FIG. 1, the compression heat pump systems 112 can be among the most widely adopted. In some examples, the compression heat pump systems 112 can include vapor compression refrigeration cycle systems where the refrigerant, e.g., natural or synthetic refrigerant, is evaporated by a heat source, followed by compression to high temperature and pressure. The vapor compression refrigeration cycle systems can use a working fluid that transfers heat to a heat sink through condensation at higher temperature, before being expanded through an expansion valve into an evaporator to complete the heat pump cycle. In some examples, the heat pump cycles can include reverse Brayton cycle heat pumps. The closed systems 106 can achieve increased heat sink temperatures and improved thermal efficiency by using (a) improved heat pump cycle configurations that can include multiple stages and intercooling, (b) improved compressors, for example, that use permanent magnet-high speed motors with magnetic bearing driven ultra-fast radial impeller based configurations, and (c) advanced working fluids including transcritical and supercritical working fluids like CO₂.

In comparison to the other heat pump systems shown in FIG. 1, the mechanical vapor recompression (MVR) systems 108 can be one of the most efficient at heating and/or cooling among the heat pump systems 102. In some examples, in contrast to compression heat pump systems 112, process fluids of the MVR systems 108 are flowed directly into a compressor of the MVR system 108 resulting in reduced equipment requirements and can simultaneously reduce exergy losses during heat transfer. The process fluids for the MVR systems 108 can include steam. MVR systems can make use of internally inter-cooled MVR heat pump cycles having steam as a working fluid. For example, the thermodynamic process development for internally inter-cooled MVR heat pump cycles can be based on a first principles approach to understanding the thermodynamics of steam production from ambient conditions. In addition to artificial refrigerants (which are being phased out), several natural working fluids can be used in vapor compression heat pumps including hydrocarbons (such as propane, butane), CO₂, and water (also known as refrigerant R-718). For MVR systems, water and/or steam can be used for process heating in medium to high pressure ranges. The benefits to using steam as a working fluid for the MVR heat pump cycle can include reduced process equipment requirements, and minimized exergy losses during heat transfer. Because of hydrogen bonding in liquid water, the heat of vaporization for water can be much higher than that of other fluids. Thus, when delivering steam at medium to high pressures from ambient conditions, most of the heat consumed in the process is used to overcome the heat of vaporization. By using a MVR type cycle using steam as working fluid, water can be evaporated at low temperature and thus most of the heat input into the process can happen at low temperature. Thermodynamically, this can provide for an efficient heating and/or cooling process (this is because entropy ˜ΔQ/T, and heat at lower temperatures is exergetically less expensive). However, the combination of (1) sub-atmospheric evaporation pressures at ambient temperatures and (2) high compressor discharge temperature for a given pressure (or temperature) lift, can result in a limited applicability of water as working fluid for MVR heat pumps. These shortcomings are shown via a pressure enthalpy (P-H) diagram in FIG. 2 and FIG. 2B.

Referring to FIG. 2, a pressure enthalpy diagram of water-steam is shown, according to some embodiments. FIG. 2 shows a plot 200 representing a high specific volume and high discharge temperature of a steam compressor resulting in low effective coefficient of efficiency (COP). The plot 200 shows isentropic compression process at 204 for a first compressor, and at 206 for a second internally inter-cooled compressor.

A technical solution is presented below that effectively addresses the technical problems described above. For example, systems and methods are presented herein that overcome the short-comings of the heat pump technology above including: (a) using a low temperature heat pump and/or using waste heat to produce low pressure steam, and (b) compressing the low pressure steam to deliver high-pressure, high-temperature steam for efficiently heating and/or cooling an area or process. In some examples, the systems and methods presented herein can take advantage of low temperature waste heat available from many industrial sites. The low temperate waste heat can be used to produce atmospheric pressure, sub-atmospheric pressure, or low pressure steam, e.g., used at (a), without much energy consumption. From ambient conditions, atmospheric pressure, or sub-atmospheric, or low-pressure steam at close to 100 degrees-C can be generated using natural refrigerant (CO₂ or hydrocarbons) heat pumps. In some embodiments, to go from atmospheric pressure or sub-atmospheric or low-pressure steam to medium-pressure or high-pressure and high-temperature steam, e.g., at (b), an internally inter-cooled recompressor, e.g., such as an MVR system, can be used. In some examples, the internally inter-cooled recompressor can be used to provide multiple stages, e.g., in some examples continuous inter-cooling can be provided by injection of cooling within the compressor, thus providing high levels of inter-cooling without any of the losses associated with the physical extraction of the working fluid from the recompressor. In a water-steam system this can be accomplished with direct injection of water droplets into the recompressor. The direct injection of water droplets can be accomplished at the right pressure and droplet size to enable effective inter-cooling. For this purpose, a fine injection nozzle integrally embedded into an impeller via 3D printing or an ultrasonic nebulizer to deliver very small diameter droplets can be used.

System for High Temperature Heat Pump

Referring to FIG. 3, a block diagram of a heat pump system is shown, according to some embodiments. As described herein, the heat pump system 300 can be referred to as a heat pump apparatus, among other terms. In some embodiments, the heat pump system 300 presented can be used to deliver high temperature heat in the form of saturated or super-heated steam. As described herein, high temperature heat can include heat within a temperature range of approximately 120-280 degrees-C. In some examples, the high temperature heat can include heat greater than 100 and/or 200 degrees-C. The high temperature heat can be transferred via (e.g., saturated or super-heated steam. The heat pump system 300 can include a first compression stage 302 and a second compression stage 304. For example, the first compression stage 302 can include a refrigerant based low-temperature heat pump that can be used to deliver low pressure steam. For example, heat transfer from the first compression stage 302 to the second compression stage 304 can be accomplished at small temperature difference. In some examples, this small temperature difference can be approximately 5 degrees-C or below 10 degrees-C. In one example, the second compression stage 304 can include an internally inter-cooled mechanical vapor recompression (MVR) compressor that is used to deliver high temperature heat to a target space and/or customer process.

Referring to FIG. 3, the first compression stage 302 can include an evaporator 306, a compressor 308, condenser 310, and an expansion valve 312. In some embodiments, the first compression stage 302 can include a closed cycle system. In some examples, the first compression stage 302 can include a compression heat pump system. The compressor 308 can be driven or powered by any source including an electric motor, a steam turbine, a heat engine, among others. At a first step 316, a working fluid (e.g., a liquid refrigerant) can be used via the evaporator 306 to absorb heat from an external source, waste heat source, and/or the environment. The heat can be absorbed by evaporating a working fluid to form vapor. The working fluid can include water, synthetic refrigerants, natural refrigerants like CO₂ or hydrocarbons like butane. Then temperature difference for heat transfer for the heat absorption (e.g., to convert liquid to vapor) can be approximately 5 degrees-C and/or less than approximately 10 degrees-C. As a result of evaporating the working fluid, the evaporator 306 can produce a heated vapor. The vapor produced at the evaporator 306 can include steam. At a second step 318, the compressor 308 can receive the vapor from the evaporator 306. The compressor 308 can compress the received vapor. The compressor 308 can increase the pressure and temperature of the received vapor to form a higher pressure, higher temperature vapor. The pressure and temperature of the vapor can be measured with respect to the received vapor from the evaporator 306. The vapor from the compressor 308 can be transferred to the condenser 310. The vapor produced at compressor 308 can include steam. At a third step 320 the condenser 310 can release heat from the vapor received from the compressor 308. The temperature of the heat released at condenser 310 can be approximately 100 degrees-C, less than 100 degrees-C, or more than 100 degrees-C and be at approximately 1 bar, less than 1 bar or more than 1 bar pressure. The condenser 310 can be located within the area and/or space to be heated to release the heat there. As a result of releasing the heat, the vapor at the condenser 310 can condense into the working fluid. The working fluid can include water. The working fluid can be transferred from the condenser 310 to the expansion valve 312. At a fourth step 320, the expansion valve 312 can reduce the pressure of the working fluid from the condenser 310. The working fluid can be transferred to the evaporator 306. The first step 316, can be performed again, going from step 320 at step 322. In one example, the first compression stage 302 is not used, and instead waste heat from a process and/or device can be used as input for the second compression stage 304. For example, waste heat from an industrial machine and/or industrial process can be used. In some embodiments, although water is used as an exemplary working fluid, other fluids and/or refrigerants can be used. For example, working fluids like propane, butane, ammonia, among others.

Referring to FIG. 3, the second compression stage 304 can include a compressor 314. In some embodiments, the second compression stage 304 can include a open cycle system. In some examples, the second compression stage 304 can include a MVR system. The second compression stage 304 can include steps 326, 328, 330, 332 for producing superheated vapor 338. The step 326 can include applying internal intercooling water directly to the compressor 314 to generate superheated vapor 338. The step 328 can include feeding ambient water, or another refrigerant in liquid state to an evaporator 324 that is in proximity to the condenser 310 of the first compression stage 302. Provided step 328 is implemented, the evaporator 324, the water, or other refrigerant is converted into vapor at approximately 1 bar pressure and approximately 100 degrees-C, more than 1 bar and 100 degree-C, or less than 1 bar and 100 degree-C. At step 330 the vapor from the evaporator 324 can be supplied to the compressor 314. The vapor can include steam. At step 332 the compressor 314 can convert the vapor from step 330 into superheated vapor 338. In some examples, during operation of the heat pump system 300 water received at an inlet 340 of the heat pump system 300 can be at 1 bar, 20 degrees-C, discharge 342 of the heat pump system 300 can include 180 degrees-C of saturated and/or superheated vapor 338. FIG. 3 shows the overall heat pump lift temperature 352 from ambient temperature 354, mid range temperature 356 (e.g., at approximately 105 degrees-C), and at the final heated vapor temperature 358 within a range of approximately 120-280 degrees-C. Although one second compression stage 304 is shown, more than one compression stage 304 can be used. In some examples, a third, fourth, and/or more compression stages that are similar and/or the same to the second compression stage 304 can be used in combination with the compression stages 302, 304. For example, a second, third, fourth, and/or more compression stages that similar and/or the same to the second compression stage 304 connected in parallel and/or series can be implemented. The compressor 314 can be driven or powered by any source including an electric motor, a steam turbine, a heat engine, among others. The compressor 314 can use a working fluid (e.g., a liquid refrigerant) can be used, e.g., via the evaporator 324. The working fluid can be the same working fluid and/or a different working fluid described for the first compression stage 302. As described above, although water is used as an exemplary working fluid, other fluids and/or refrigerants can be used. For example, working fluids like propane, butane, ammonia, among others.

Referring to FIG. 3, in some embodiments, the heat pump system 300 can include multiple compressors 308, 314 arranged in series and/or in parallel is presented. In some examples, the multiple compressors 314, can be arranged in parallel to increase the flow rate of refrigerant at the same pressure ratios. In one example, multiple compressors 314 can be arranged in series to increase the pressure ratio at same flow rate. The arrangement of the compressors in series to increase the overall pressure ratio can be referred to as stages. In a non-limiting example, the multiple stages arranged in series can include inter-cooling by heat rejection to another fluid like air or water using a heat exchanger. Inter-cooling can also be achieved by direct injection of the liquid into the vapor stream for direct contact cooling. In an example, a few stages of the series compressor arrangement can include parallel compressors to increase the mass flow rate. Each compressor 308, 314 can include an inlet plenum, a shrouded impeller, a diffuser, and/or an exit plenum. In one embodiment, the multiple compressors of the heat pump system can share several of these components while other components are custom built to optimize cost via volume production of shared components. In some embodiments, a physics-based modeling tool can be used to automatically compute and/or optimize a gas flow path for the heat pump system 300. The physics-based modeling tool can be used to compute and optimize gas flow path and deliver 3D configuration that can be printed using metal 3D printing technologies. In some examples, the modeling can be performed based on input from customer requirements. In some embodiments, one or more artificial intelligence algorithms can be used to automatically compute and/or optimize a gas flow path for the heat pump system 300. In some examples, machine learning algorithms, neural network algorithms, reinforcement learning algorithms, among other algorithms can be used to automatically compute and/or optimize a gas flow path for the heat pump system 300. In one example, the artificial intelligence algorithms can be trained on gas flow path data, and based on the training, the artificial intelligence algorithms can be used to automatically compute and/or optimize a gas flow path that can be configured for mechanical integrity, reliability and manufacturing at optimal costs for the heat pump system 300. The heat pump system 300 can include a vapor and/or gas compressor configuration with integrated cooling via a droplet injection system. The droplet injection system can include a droplet generation mechanism and a droplet injection location. The droplet generation system can me a mechanical system wherein droplets are created using a high-pressure water source that is forced through small diameter nozzles to make fine droplets. The droplet generation system can also utilize other technologies like ultrasonic nebulizers that may generate droplets at small diameters using an ultrasonic membrane. The droplet injection location can be implemented along the gas compression path within the compressor. The injection location is determined to optimize the cooling effect on the compressing vapor to minimize the work requirement from the compressor shaft. The droplet injection system can be built into the compressor wheel or impeller. Metal 3D printing technology can be used to form the impeller of the integrated cooling system. The system can include an integrated droplet injection and cooling configuration that injects water droplets that can be small enough to cause evaporation within a gas flow path of the impeller itself such that the resulting cooling effect causes reduced compression work requirements. The droplets can be approximately 1 micron or less in diameter. In some examples, the droplets can be 0.1 micron to 0.01 micron, or smaller in diameter to allow effective evaporation with the compression flow path. The droplet injection system can be used for droplet injection within the impeller that uses an ultrasonic nebulizer to create droplets having a diameter in the order of approximately 0.1 micron, less than 0.01 micron, 1 micron, 10 micron, and greater than 10 micron diameter dimensions. The droplet injection configuration can be located within the impeller gas such that the droplet injection configuration provides cooling via droplet evaporation. In some examples, as the droplet evaporation cools the steam flow within the compressor, it increases the volumetric flow rate due to added vapor mass improving compressor performance, that is increases pressure at reduced work requirements. The system can include an injection port. The location of the injection port along with a droplet diameter can be co-optimized using analytical and/or computational tools including computation fluid dynamics tools.

In some embodiments, the compressor 308 and the compressor 314 include one or multiple compressors that are connected in series or parallel. 6. In some examples, the compressors 308, 314 can be configured to receive custom impellers, stators, and/or diffusers. The custom impellers and/or stators can be formed using software tools and/or methods to deliver optimized impeller and/or stator configurations. The custom impellers and/or stators can be manufactured using metal three-dimensional printing systems and/or methods. The compressors 308, 314 where, provided the compressors 308, 314 include multiple compressors, the multiple compressors can be connected with piping that is rigid and/or with flexible hoses. The flexible hoses can have provisions for cooling. In some examples, the multiple compressors can perform intercooling and where in the intercooling can be performed using a heat exchanger. In one example, another difference fluid (e.g., from water) can be used with the multiple compressors. The intercooling can be performed using a superheated vapor which can be formed via injection of the high-pressure liquid droplets directly into the interconnecting piping between at least two compressors of the multiple compressors. The intercooling can use liquid droplet evaporation which can increased mass flow rate of the vapor. The multiple compressors can be referred to as a compressor train. The compressors 308, 314 can be internally cooled using droplet injection in a compression flow path. The compressors 308, 314 where the internal cooling with droplets can be achieved by injection of droplets through a nozzle on the impeller. In some examples, internal cooling with droplets can be achieved by injecting of the droplets through a nozzle on a diffuser or stator. In an example, droplets can be generated using injection of high-pressure liquid through a restricted orifice or nozzle. In one example, the droplets can be generated using an ultrasonic nebulizer or vibrating membrane at high frequency and injected through a nozzle. The location of the droplet injection can be positioned to minimize the compressor work done by effective cooling of the compressing gas. A compressor geometry can be modified to optimize for increased mass flow rate and reduced temperature from internal cooling within a compression path.

In some embodiments, as described above high temperature heat can include temperatures in a range of 120 to 280 degrees-C. The first and second compressors 308, 314 can include a plurality of compressors connected in series or parallel. The plurality of compressors can be connected with at least one of rigid piping or flexible hoses. The heat pump system 300 can include an intercooler that cools the first working fluid before entering at least one compressor of the plurality of compressors. The intercooler can inject high-pressure liquid droplets into at least one compressor of the plurality of compressors. The intercooler can inject high-pressure liquid droplets through a nozzle of an impeller of the first compression stage.

Referring to FIG. 4, a block diagram of an internally cooled multi-stage MVR system is shown, according to some embodiments. In some embodiments, the internally cooled multi-stage MVR system 400 can include an exit nozzle 402, an exit collector 404, a diffuser 406, a motor 408, an inlet plenum 410, an impeller 412, a shaft 414, and bearings 416. In some examples, the cooling fluid can be injected through the shaft 414, and ejected through nozzles embedded in the impeller 412. The cooling fluid can be injected through nozzles embedded in the diffuser 406 or exit collector 404.

Methods for High Temperature Heat Pump

Referring to FIG. 5, a flowchart 500 of a method for delivering heat using a high temperature heat pump apparatus is shown, according to some embodiments. In step 502, the method includes evaporating, using a first evaporator, a first working fluid to form a first vapor. In step 504, the method includes compressing, using a first compressor, the first vapor evaporated in the evaporator to increase the pressure of the first vapor. In step 506, the method includes condensing, using a condenser, the first vapor having increased pressure to deliver heat. In step 508, the method includes evaporating, using a second evaporator, a second working fluid using the heat from the condenser to form a second vapor. In step 510, the method includes compressing, using a second compressor, the second vapor to deliver high temperature heat.

In some embodiments, compressing at step 504 the first vapor can include compressing using the first compressor having a plurality of compressors. In some examples, the method 500 can further include intercooling, using an intercooler, the first working fluid before entering at least one compressor of the plurality of compressors. Intercooling the first working fluid can include injecting high-pressure liquid droplets into the least one compressor of the plurality of compressors. Injecting high-pressure liquid droplets can include injecting high-pressure liquid droplets through a nozzle of an impeller. Injecting high-pressure liquid droplets can include injecting high-pressure liquid through at least one of a restricted orifice or nozzle. Compressing, at step 510, the second vapor can include compressing using the second compressor having a plurality of compressors. The first working fluid and the second working fluid can include water. In some examples, the first working fluid can include a different fluid from the second working fluid. The high temperature heat can include temperatures in a range of 120 to 280 degrees-C.

Compressors for High Temperature Heat Pump

Heat pump systems use compressors to convert low-pressure, low-temperature vapor into high-pressure, high-temperature vapor for heat delivery. Therefore it can be fair to categorize the importance of the compressor in allowing the heat pump systems described herein in reaching their heat delivery output, e.g., at higher temperatures. Exemplary compressor technologies that can be used for high temperature heat pumps can include (1) piston compressors, (2) screw compressors, (3) turbo compressors, and (4) centrifugal fans and blowers. Piston and screw compressors dominate the market, while scroll compressors are used in some pre-commercial demonstration applications. Positive displacement machines, which can include piston and screw compressors, can be susceptible to higher vibration levels which can lead to increased operations and maintenance costs in comparison to the other compressor systems. Furthermore, because steam can have high swept volumes at relevant pressures, positive displacement machines are more suited for use with other refrigerants that have lower specific volumes but not water or steam. Centrifugal fans and blowers can provide for higher thermal capacities over piston and screw compressor, however, the compression ratio per stage for centrifugal fans can be rather low, e.g., corresponding to low temperature lift per stage of approximately <5 degrees-C or less than 10 degrees-C. Turbo-compressors can make use of oil bearings and planetary gearboxes. For high temperature heat pump applications, the use of lubrication oil can affect reliability and risk steam contamination. In addition, the use of gearboxes adds complexity and further operations and maintenance cost. A technical solution to finding a compressor that can allow for heat delivery output, e.g., at higher temperatures, for the heat pump systems described herein is presented below.

In some embodiments, the compressors can include stators, impellers, among other components. The stators can also be referred to as diffusers. In some examples, the impellers and/or stators can be adjusted for various source temperatures and flow rates. The impellers and/or stators can be adjusted to the compressor systems described herein while maintaining the rest of the compressor system's components. Metal 3D printing technologies like direct laser metal sintering (DLMS) can also be used to form impellers and stators. Metal 3D printing can also be used to form impellers and stators to specific cooling geometries for use with the heat pump systems described herein. Depending on the source temperature for a given thermal size, a target heating process, and/or customer requirement, the series and parallel arrangement of compressors as well as the optimal geometry of the impeller and/or stator components can be adjusted accordingly. In one example, the rest of the components compressor can be kept identical while the impellers and/or stators can be customized. Adjustments to the impeller and/or stator components can result in changes in source temperature and/or the lift temperature.

Referring to FIG. 6, a compressor stage diagram is shown, according to some embodiments. In some embodiments, the compressor 600 can include a stator 610, and impeller 612. Initial outline of the inlet of the volute 614 is also shown. FIG. 6 shows exemplary height 616 and width 618 dimensions for the compressor 600.

Referring to FIG. 7, impeller diagrams for five compressor stages are shown, according to some embodiments. In a non-limiting example, five impeller diagrams 702, 704, 706, 708, 710 corresponding to five compressor stages are shown. Each of the impellers 702, 704, 706, 708, 710 can deliver high efficiency performance at 89% isentropic efficiency for different flow rates, pressures, and temperatures. The compressor stages corresponding to the impellers 702, 704, 706, 708, 710 can run at high isentropic efficiency at optimal speeds and can deliver an effective process heating rate, but at highly variable source and lift temperatures. In an example, the impellers 702, 704, 706, 708, 710 can each have their own stator 712 configurations as well as operating speed. In some examples, the impellers 702, 704, 706, 708, 710 can each be integrated into a same or similar rotating machine configuration with source and lift temperature combinations of at least one of (a) 85 degrees-C source and 25 degrees-C lift for the compressor of impeller 702, (b) 110 degrees-C source and 20 degrees-C lift for the compressor of impeller 704, (c) 130 degrees-C source and 20 degrees-C lift for the compressor of impeller 706, (d) 110 degrees-C source and 30 degrees-C lift for the compressor of impeller 708, or (e) 130 degrees-C source and 30 degrees-C lift for the compressor of impeller 710. Each of the stators and corresponding impellers 702, 704, 706, 708, 710 can have configurations that can be 3D printed.

In some embodiments, 3D printed impellers and stators of different dimensions can be integrated into the same electrical and rotating machine casing to deliver different source and lift temperature combinations. The configurations presented herein can provide for reduced hardware variation, and increased production volumes. In some examples, the impellers and stators described herein can be tailored to customer requests and 3D printed. In one example, while the impellers and stators are 3D printed the rest of the compressor system can be mass produced in an assembly line. The configurations described herein are not limited to impellers and/or stators for use with water and can be used, configured, and/or developed for other type of turbomachinery including compressor designs for heat pumps that use working fluids like propane, butane, ammonia, and other refrigerants, expander, turbine, or turbomachinery designs for power generation using various working fluids, or cooling systems and chillers for process and space cooling using various fluids.

Referring to FIG. 8, an exemplary radial compressor impeller is shown, according to some embodiments. For example, a profile view 802 and a cross-sectional view 804 of an impeller 800 is shown. In some embodiments, the impeller 800 can include a shroud 806 and vanes and blades 808. The impeller 800 can be 3D printed using direct metal laser sintering (DMLS) on a Velo 3D® machine for higher-performance turbo-compressor applications. In some embodiments, impeller and stator components of the compressor systems described herein can be formed using 3D printing. In some examples, the impeller 800 can be formed using a 3D printer.

Improvements Over Conventional Heat Pump Technology

In some examples, concerns that limit the applicability of the heat pump technology for industrial process heating in (a) commercial and light industrial buildings, (b) food and beverage industry, and (c) renewable fuels and chemicals can include: (1) techno-economics and competitiveness with natural gas as a source of process heat including total lifecycle cost and operations and maintenance of heat pumps, and (2) system complexity and difficulty of process integration.

According to International Energy Agency (IEA), the final energy demand for heating and cooling was >6 petawatt-hour (PWh) in 2022. The industry accounted for more than 40% of this demand, related to the need for process heating. A very high fraction (30-40%) of this demand is for process heating in the <200 degrees-C range. In this aspect high temperature heat pumps have been recognized as a promising solution to supply heat at elevated temperatures, as they can achieve COP values well above 1. Such demand is currently available in sectors such as (1) commercial and light industrial buildings, (2) food and beverage industries, (3) renewable fuels and chemicals, (4) plastics and (4) ore refining, as well as several other processing industries.

In some examples, to accomplish continuous heat output for industrial processes, most heat pump solutions in the market offer custom units requiring substantial operations, maintenance, and overhead costs to customers. In one example, oil lubricated compressors of conventional heat pump solutions can include significant spares and inventory in addition to personnel for maintenance. In contrast, magnetic bearing machines can have ultra-low maintenance requirements and by adopting a modular approach wherein each machine is identical, the number of spares required can be reduced to negligible as these are no longer customized to a given heat pump configuration. In addition, based on the embodiments described herein, the improved COP performance by deploying internal inter-cooling of steam in the recompressor train can result in improved margins over incumbent technologies like natural gas fired boilers. Using an internal inter-cooling of steam in the recompressor train can increase a feasible application range of the heat pump systems from a lift temperature in the range of 100-120 degrees-C to greater than 150 degrees-C. Furthermore, there are inherent benefits of using a multi-stage heat pump configurations. In one example, using the same process gas (e.g., steam) for a compression heat pump, e.g., first compression stage, and a MVR system, e.g., a second compression stage, can result in minimal balance and/or reduced number of plant equipment other than the recompressors, evaporators, and condensers used, among other components. Therefore, the systems and methods presented herein can provide improved heat delivery method and apparatus, and provide for reduced operations and maintenance requirements against competing heat pump technologies.

Hardware and Software Implementations

FIG. 9 is a block diagram of an example system 900 that may be used in implementing the technology described in this document. As described herein, the system 900 can also be referred to as a computer system 900, among other terms. General-purpose computers, network appliances, mobile devices, or other electronic systems may also include at least portions of the system 900. The system 900 includes a processor 902, a memory 904, a storage device 906, and an input/output device 908. Each of the processor 902, 904, 906, and 908 may be interconnected, for example, using a system bus 910. The processor 902 is capable of processing instructions for execution within the system 900. In some implementations, the processor 902 is a single-threaded processor. In some implementations, the processor 902 is a multi-threaded processor. The processor 902 is capable of processing instructions stored in the memory 904 or on the storage device 906.

The memory 904 stores information within the system 900. In some implementations, the memory 904 is a non-transitory computer-readable medium. In some implementations, the memory 904 is a volatile memory unit. In some implementations, the memory 904 is a nonvolatile memory unit.

The storage device 906 is capable of providing mass storage for the system 900. In some implementations, the storage device 906 is a non-transitory computer-readable medium. In various different implementations, the storage device 906 may include, for example, a hard disk device, an optical disk device, a solid-date drive, a flash drive, or some other large capacity storage device. For example, the storage device may store long-term data (e.g., database data, file system data, etc.). The input/output device 908 provides input/output operations for the system 900. In some implementations, the input/output device 908 may include one or more of a network interface devices, e.g., an Ethernet card, a serial communication device, e.g., an RS-232 port, and/or a wireless interface device, e.g., an 802.11 card, a 3G wireless modem, or a 4G wireless modem. In some implementations, the input/output device may include driver devices configured to receive input data and send output data to other input/output devices, e.g., keyboard, printer and display devices 912. In some examples, mobile computing devices, mobile communication devices, and other devices may be used.

In some implementations, at least a portion of the approaches described above may be realized by instructions that upon execution cause one or more processing devices to carry out the processes and functions described above. Such instructions may include, for example, interpreted instructions such as script instructions, or executable code, or other instructions stored in a non-transitory computer readable medium. The storage device 906 may be implemented in a distributed way over a network, for example as a server farm or a set of widely distributed servers, or may be implemented in a single computing device.

Although an example processing system has been described in FIG. 9, embodiments of the subject matter, functional operations and processes described in this specification can be implemented in other types of digital electronic circuitry, in tangibly-embodied computer software or firmware, in computer hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a tangible nonvolatile program carrier for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. The computer storage medium can be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of one or more of them.

The term “system” may encompass all kinds of apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. A processing system may include special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). A processing system may include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them.

A computer program (which may also be referred to or described as a program, software, a software application, a module, a software module, a script, or code) can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

The processes and logic flows described in this specification can be performed by one or more programmable computers executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

Computers suitable for the execution of a computer program can include, by way of example, general or special purpose microprocessors or both, or any other kind of central processing unit. Generally, a central processing unit will receive instructions and data from a read-only memory or a random access memory or both. A computer generally includes a central processing unit for performing or executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices.

Computer readable media suitable for storing computer program instructions and data include all forms of nonvolatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; and magneto optical disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

Embodiments of the subject matter described in this specification can be implemented in a computing system that includes a back end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), e.g., the Internet.

The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. Other steps or stages may be provided, or steps or stages may be eliminated, from the described processes. Accordingly, other implementations are within the scope of the following claims.

Terminology

The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

The term “approximately”, the phrase “approximately equal to”, and other similar phrases, as used in the specification and the claims (e.g., “X has a value of approximately Y” or “X is approximately equal to Y”), should be understood to mean that one value (X) is within a predetermined range of another value (Y). The predetermined range may be plus or minus 20%, 10%, 5%, 3%, 1%, 0.1%, or less than 0.1%, unless otherwise indicated.

The indefinite articles “a” and “an,” as used in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” The phrase “and/or,” as used in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

As used in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

As used in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

The use of “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof, is meant to encompass the items listed thereafter and additional items.

Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed. Ordinal terms are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term), to distinguish the claim elements.

Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only.