Steam generation unit using a heat exchanger

Abstract

A steam generation unit includes a heat exchanger that has a shell, end plates for receiving a process fluid in a volume defined by the shell and the end plates, and channels for a working fluid. The shell and the channels define at least a first heat exchange zone, a second heat exchange zone, and a third heat exchange zone each having a respective pass of the channels for preheating the process fluid, for boiling the process fluid, and for superheating the process fluid, respectively. The process fluid is heated sequentially from the first to the second to the third heat exchange zone. A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a refrigerant circuit with a compressor, a steam generation unit, an expander, and an evaporator fluidly connected.

Description

FIELD

[0001] The disclosure relates generally to a heating, ventilation, air-conditioning, and refrigeration (“HVACR”) system, and more particularly to a HVACR system for vaporizing a process fluid using a shell and tube-type heat exchanger in which a working fluid is used as a heat source.BACKGROUND

[0002] A HVACR system may generally include a compressor and heat exchangers (e.g. a condenser and an evaporator) to form a refrigeration circuit. The heat exchangers can be used as a condenser and / or an evaporator. In a shell and tube-type heat exchanger, the heat exchanger generally includes heat-exchange tubes that extend across a shell. For example, in an evaporator, the heat-exchange tubes can be configured to carry a first fluid (such as water) forming a tube side; and the shell is configured to carry a second fluid (such as refrigerant) forming a shell side. The tube side and the shell side can form a heat exchanging relationship in the heat exchanger. The heat exchanger can help exchange heat between the first fluid in the tube side with the second fluid in the shell side.SUMMARY

[0003] With the ongoing efforts for the decarbonization of steam generation, e.g., for providing thermal energy for various industries, such as, the healthcare industry, industrial applications, homes, buildings, food processing, or the like, the utilization and / or recovery of various heat sources is desirous to reduce the need for fossil fuel-based heat / steam generation.

[0004] As such, embodiments disclosed herein provide a special purpose heat exchanger used in a steam generation unit for utilizing and / or recapturing the heat generated in a HVACR system, e.g., during the compression cycle in a vapor-compression circuit to vaporize a process fluid, for example, water to generate steam.

[0005] In an embodiment, a steam generation unit for a heating, ventilation, air conditioning, and refrigeration ( HVACR) system includes a mixed-phase heat exchanger. The mixed-phase heat exchanger includes a shell and end plates for receiving a process fluid in a volume defined by the shell and the end plates, and channels disposed inside the shell. The shell includes a process fluid inlet at a bottom of the shell for receiving the process fluid and a process fluid outlet at a top of the shell for discharging the process fluid. The channels extend between the end plates to pass a working fluid for heat exchange with the process fluid in the volume of the shell. The shell and the channels are configured to define at least a first heat exchange zone, a second heat exchange zone, and a third heat exchange zone. The first heat exchange zone includes a first pass of the channels for preheating the process fluid in the volume of the shell. The second heat exchange zone includes a second pass of the channels for boiling the process fluid in the volume of the shell. The third heat exchange zone includes a third pass of the channels for superheating the process fluid in the volume of the shell. The steam generation unit is configured to heat the process fluid sequentially from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone. The third pass of the channels includes a working fluid inlet that is configured to receive the working fluid and the first pass of the channels includes a working fluid outlet that is configured to return the working fluid.

[0006] In an embodiment, the third pass of the channels are for de-superheating the working fluid, the second pass of the channels are for condensing the working fluid, and the first pass of the channels are for subcooling the working fluid. The steam generation unit is configured to cool the working fluid sequentially from the third heat exchange zone to the second heat exchange zone to the first heat exchange zone.

[0007] In an embodiment, the stream generation unit includes a liquid heat exchanger and a gas heat exchanger. The first process fluid is sequentially heated by the liquid heat exchanger, the mixed-phase heat exchanger, and the gas heat exchanger in that order. The working fluid is sequentially cooled by the gas heat exchanger, the mixed-phase heat exchanger, and the liquid heat exchanger in that order.

[0008] In an embodiment, the channels in the first pass of the channels, the channels of the second pass of the channels, and the channels of the third pass of the channels are separate channels from each other.

[0009] In an embodiment, the end plates includes distribution chambers. Each of the channels extends from a first respective one of the distribution chambers to a second respective one of the distribution chambers.

[0010] In an embodiment, the distribution chambers include an inlet distribution chamber, a first intermediate distribution, a second intermediate distribution, and an outlet distribution chamber. The inlet distribution chamber is configured to supply the working fluid to each of the channels in the first pass. The first intermediate distribution chamber is configured to direct working fluid from the channels in the first pass and to each of the channels in the second pass. The second intermediate distribution chamber is configured to direct the working fluid from the channels in the second pass and to each of the channels in the third pass. The outlet distribution chamber is configured to receive the working fluid from the channels in the third pass.

[0011] In an embodiment, the heat exchanger includes tubes that extends from a first one of the end plates to a second one of the end plates. Each of the channels is formed by a respective tube in the tube bundle.

[0012] In an embodiment, the steam generation includes a process fluid return line and a level controller. The process fluid return line is fluidly connected to the shell of the mixed-phase heat exchanger. The level controller is configured to control a liquid level of the process fluid in the shell by controlling discharge of the working fluid through the process fluid return line.

[0013] In an embodiment, the level controller is configured to control the liquid level to be within the third heat exchange zone above at least one row of the channels of the third pass and below at least one row of the channels of the third pass.

[0014] In an embodiment, a heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a refrigerant circuit with a compressor, a steam generation unit, an expander, and an evaporator fluidly connected. The refrigerant circuit includes a working fluid. The steam generation unit is configured to heat the first process fluid using the working fluid compressed by the compressor. The mixed-phase heat exchanger includes a shell and end plates for receiving a first process fluid in a volume defined by the shell and the end plates, and channels disposed inside the shell. The shell includes a process fluid inlet at a bottom of the shell for receiving the first process fluid and a process fluid outlet at a top of the shell for discharging the first process fluid. The channels extend between the end plates to pass a working fluid for heat exchange with the first process fluid in the volume of the shell. The shell and the channels are configured to define at least a first heat exchange zone, a second heat exchange zone, and a third heat exchange zone. The first heat exchange zone includes a first pass of the channels for preheating the first process fluid in the volume of the shell. The second heat exchange zone includes a second pass of the channels for boiling the first process fluid in the volume of the shell. The third heat exchange zone includes a third pass of the channels for superheating the first process fluid in the volume of the shell. The steam generation unit is configured to heat the first process fluid sequentially from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone. The third pass of the channels includes a working fluid inlet that is configured to receive the working fluid and the first pass of the channels includes a working fluid outlet that is configured to return the working fluid.

[0015] In an embodiment, the third pass of the channels are for de-superheating the working fluid, the second pass of the channels are for condensing the working fluid, and the first pass of the channels are for subcooling the working fluid. The steam generation unit is configured to cool the working fluid sequentially from the third heat exchange zone to the second heat exchange zone to the first heat exchange zone.

[0016] In an embodiment, the channels in the first pass of the channels, the channels of the second pass of the channels, and the channels of the third pass of the channels are separate channels from each other.

[0017] In an embodiment, the steam generation unit includes a liquid heat exchanger and a gas heat exchanger, and the refrigerant circuit includes the liquid heat exchanger and the gas heat exchanger. The first process fluid is sequentially heated by the liquid heat exchanger, the mixed-phase heat exchanger, and the gas heat exchanger in that order. The working fluid is sequentially cooled by the gas heat exchanger, the mixed-phase heat exchanger, and the liquid heat exchanger in that order.

[0018] In an embodiment, the gas heat exchanger is configured to reduce a superheat of the working fluid and increase a superheat of the first process fluid. The liquid heat exchanger is configured to increase a subcooling of the working fluid and decrease subcooling of the first process fluid.

[0019] In an embodiment, the end plates include distribution chambers, each of the channels extends from a first respective one of the distribution chambers to a second respective one of the distribution chambers.

[0020] In an embodiment, the distribution chambers include an inlet distribution chamber, a first intermediate distribution chamber, a second intermediate distribution chamber, and an outlet distribution chamber. The inlet distribution chamber is configured to supply the working fluid to each of the channels in the first pass. The first intermediate distribution chamber is configured to direct working fluid from the channels in the first pass and to each of the channels in the second pass. The second intermediate distribution chamber is configured to direct the working fluid from the channels in the second pass and to each of the channels in the third pass. The outlet distribution chamber is configured to receive the working fluid from the channels in the third pass.

[0021] In an embodiment, the heat exchanger includes tubes that extends from a first one of the end plates to a second one of the end plates. Each of the channels is formed by a respective tube in the tube bundle.

[0022] In an embodiment, the HVACR system includes a process fluid return line fluidly connected to the shell of the mixed-phase heat exchanger and a level controller. The first process fluid is discharged through the process fluid return line configured to be mixed with an inlet stream of the process fluid flowing to the shell. The level controller is configured to control a liquid level of the first process fluid in the shell by controlling discharge of the first process fluid through the process fluid return line.

[0023] In an embodiment, the level controller is configured to control the liquid level to be within the third heat exchange zone above at least one row of the channels of the third pass and below at least one row of the channels of the third pass.

[0024] In an embodiment, the compressor is for compressing a working fluid, the steam generation unit is for cooling the working fluid with the first process fluid, the expander is for expanding the working fluid cooled by the steam generation unit, and the evaporator is for cooling the working fluid expanded by the expander using a second process fluid.

[0025] In an embodiment, a steam generation unit is provided. The steam generation unit includes a heat exchanger having a shell and end plates for receiving a process fluid in a volume defined by the shell and the end plates; and a plurality of channels disposed inside the shell that extend between the end plates of the heat exchanger to pass a working fluid for heat exchange with the process fluid in the volume of the shell. The shell includes a process fluid inlet at a bottom of the shell for receiving the process fluid and a process fluid outlet at a top of the shell for exiting the process fluid. The shell and the plurality of channels are configured to define at least a first heat exchange zone including a first pass of the plurality of channels for preheating the process fluid in the volume of the shell, a second heat exchange zone including a second pass of the plurality of channels for boiling the process fluid in the volume of the shell, and a third heat exchange zone including a third pass of the plurality of channels for superheating the process fluid in the volume of the shell. Additionally, the steam generation unit is configured to heat the process fluid sequentially from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone, and the third pass of the channels includes a working fluid inlet that is configured to receive the working fluid and the first pass of the channels includes a working fluid outlet that is configured to return the working fluid.

[0026] Other features and aspects of the embodiments will become apparent by consideration of the following detailed description and accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Reference is now made to the drawings in which like reference numbers represent corresponding parts throughout.

[0028] FIG. 1 illustrates a schematic diagram of an embodiment of a heating, ventilation, air conditioning, and refrigeration (HVACR) system.

[0029] FIG. 2 illustrates a schematic diagram of an embodiment of a heating, ventilation, air conditioning, and refrigeration (HVACR) system.

[0030] FIG. 3A illustrates a left perspective view of an embodiment of a heat exchanger for a steam generation unit.

[0031] FIG. 3B illustrates a right perspective view of the heat exchanger of FIG. 3A, according to an embodiment.

[0032] FIG. 4 is a sectional side view of an embodiment of a heat exchanger for a steam generation unit of an HVACR system.

[0033] FIGS. 5A and 5B illustrate a steam generation unit as a shell and tube-type heat exchanger having tube configurations, according to an embodiment.

[0034] FIG. 6 is an illustration of tube configurations having fins, according to an embodiment.

[0035] FIG. 7 is an illustration of tube configurations having fins, according to another embodiment.

[0036] FIGS. 8A, 8B, 8C shows different configurations of the passes for tube configurations, according to an embodiment.

[0037] FIGS. 9A, 9B, 9C illustrate a steam generation unit as a shell and tube-type heat exchanger having plate configurations, according to an embodiment.

[0038] FIGS. 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I illustrate various plate configurations, according to various embodiments.

[0039] FIGS. 11A and 11B illustrates a steam generation unit as a shell and tube-type heat exchanger having plate configurations, according to an embodiment.

[0040] FIGS. 12A and 12B illustrate a steam generation unit as a shell and tube-type heat exchanger having pillow-plate configurations, according to an embodiment.

[0041] FIGS. 13A and 13B illustrate a steam generation unit as a shell and tube-type heat exchanger having pillow-plate configurations, according to another embodiment.

[0042] Like numbers represent like features.DETAILED DESCRIPTION

[0043] Numerical terminology (e.g., first, second, third, etc.) as used herein for features are for clearly differentiating individual feature(s) among a group of said features and does not imply any particular sequence or ordering of said features relative to each other. For example, a description of a first X feature, a second X feature, and a third X feature does not imply that first X feature, the second X feature, and the third X feature occur in (or are disposed in) said order and allows for additional X feature(s) to occur (or be disposed) before or between the first X feature, the second X feature, and the third X feature.

[0044] The disclosure relates generally to a heating, ventilation, air-conditioning, and refrigeration (“HVACR”) system, and more particularly to a HVACR system for vaporizing a process fluid using a shell and tube-type heat exchanger in which a working fluid is used as a heat source.

[0045] Various shell and tube-type heat exchangers have been developed. For example, shell and tube-type heat exchangers can be a shell and tube heat exchanger, a plate heat exchanger, or the like, in which a first fluid is provided in channels for exchanging heat with a second fluid provided in a shell of the heat exchanger. Typically, a shell and tube heat exchanger has a structure that includes heat exchanging tubes that extend in a shell. The heat exchanging tubes form tube side channels configured to carry a first fluid, and the shell forms a shell side configured to carry a second fluid along outer surfaces of the tubes. The tube side channels and the shell side are formed in a heat exchanging relationship in the heat exchanger.

[0046] With the ongoing efforts for the decarbonization of steam generation, e.g., for providing thermal energy for various industries, such as, the healthcare industry, industrial applications, homes, buildings, food processing, or the like, the utilization and / or recovery of various heat sources is desirous to reduce the need for fossil fuel-based heat / steam generation.

[0047] As such, embodiments disclosed herein provide a special purpose heat exchanger used in a steam generation unit for utilizing and / or recapturing the heat generated in a HVACR system, e.g., during the compression cycle in a vapor-compression circuit to vaporize a process fluid, for example, water, to generate steam. In an embodiment, the heat exchanger has at least three zones or regions including, but not limited to, a first zone which is a water pre-heating / refrigerant subcooling region, a second zone which is a water boiling / refrigerant condensation region, and a third zone which is a steam superheater / refrigerant desuperheater region. Each zone or region is configured for its heat transfer phase of the process fluid, e.g., single phase or two-phase region.

[0048] FIG. 1 is a schematic diagram of HVACR system 100 for heating and / or cooling a process fluid using a compression cycle of a working fluid, in which the HVACR system 100 includes a steam generation unit 110 according to an embodiment. The process fluid(s) can be part of an industrial process, for example, process fluids for reactions, industrial waste, refrigeration lines, heating lines, or the like, or for a hydronic system for conditioning a space or building.

[0049] The working fluid can be any suitable working fluid. The working fluid includes one or more refrigerants (e.g., single refrigerant, refrigerant blend). The refrigerant(s) in the working fluid are not limited to any particular refrigerant, and in some embodiments, the refrigerant(s) can be selected from one or more of R1234yf, R134a, R1234ze(E), R1234ze(Z), R245fa, R1233zd(E), R1336mzz(Z), R365mfc, R600a, R600, R601, R717, R744, R718, and R1224yd(Z). In an embodiment, the process fluid is water. The working fluid may also include one or more additional components other than refrigerant(s). For example, an additional component may include, but is not limited to, lubricants, impurities, refrigeration system additives, tracers, ultraviolet (“UV”) dyes, and / or solubilizing agents. With reference to the working fluid, it should be appreciated that “condensing” (or other references to the phase change of the working fluid) refers to the of condensing and phase change of the refrigerant(s) in the working fluid.

[0050] In the embodiment shown in FIG. 1, the HVACR system 100 is configured as a heat pump. It is understood that the HVACR systems can be other systems that include a compressor such as, a chiller system, other reversible systems, or any other suitable system providing heating and / or cooling through a compression cycle of a working fluid.

[0051] The HVACR system 100 includes a heat transfer circuit that includes a compressor 105, a steam generation unit 110, an economizer 130, one or more expansion devices 132, and an evaporator 134. In some embodiments, the heat transfer circuit can be modified to include additional components. For example, the heat transfer circuit can include one or more additional economizer heat exchangers, one or more flow control devices, a receiver tank, a dryer, a suction-liquid heat exchanger, a controller, or the like.

[0052] The compressor 105 is configured to compress the working fluid. Compressor 105 can be any suitable compressor, such as a screw compressor, a scroll compressor, a centrifugal compressor, or the like. Working fluid discharged from compressor 105 can pass to the steam generation unit 110 (e.g., the compressed working fluid from the compressor 105 flows into the stream generation unit 110).

[0053] The steam generation unit 110 includes one or more heat exchangers allowing the working fluid to reject heat to a process fluid, thereby heating the process fluid, e.g., for heating water to generate steam. In an embodiment, as further discussed below, the steam generation unit 110 can include a first heat exchange zone 112, a second heat exchange zone 114, and a third heat exchange zone 116. The first heat exchange zone 112 can be, for example, a process fluid preheating zone or heat exchanger for preheating the process fluid, such as water, to the required temperature, e.g., saturated boiling temperature. The second heat exchange zone 114 can be, for example, a boiling or vaporization zone or heat exchanger for boiling the preheated / saturated process fluid. The third heat exchange zone 116 can be, for example, a superheating zone or heat exchanger 116 for superheating the vaporized / boiled process fluid, e.g., steam.

[0054] For example, in an embodiment, the water is heated to around 99°C or higher at 1 ATM in the first heat exchange zone 112, while the working fluid in the first heat exchange zone 112 is subcooled. The preheated water from the first heat exchange zone 112 can then enter the second heat exchange zone 114, in which the water undergoes heating to reach the saturated boiling water temperature, after which, the water boils and transitions into steam and is at least partially superheated by the working fluid, while the working fluid is condensed. In the second heat exchange zone 114, the heating of the water to saturated boiling water temperature is slight single phase heating (1-2°C) and / or subcooled boiling of the water. The steam from second heat exchange zone 114 enters the third heat exchange zone 116 in which the steam is further superheated to the predetermined temperature before it exits the steam generation unit 110, while the working fluid is de-superheated and partially condensed.

[0055] The working fluid can pass from the steam generation unit 110 to economizer 130 that can include expander(s) 132. The economizer 130 can be a refrigerant-refrigerant heat exchanger (e.g., liquid-gas heat exchanger or the like). At expander(s) 132 the working fluid is expanded. Expander(s) 132 can be any suitable expander, such as at least one expansion valve, expansion orifice, orifice plate, expansion nozzle, a controllable expander, such as an electronic expansion valve, combinations thereof, or the like. Working fluid can pass from an expander 132 to evaporator 134 where the working fluid can extract heat from a source such as for cooling a cooling load or coolant, thereby evaporating the working fluid prior to the working fluid returning to compressor 105. The sources can be, for example, from a process fluid or a conditioned space to be cooled, from an ambient environment, or the like, so as to evaporate the working fluid. Non-limiting examples of evaporator 134 can include an evaporator of a chiller configured to cool a process fluid, or the like. Working fluid leaving the evaporator 134 can be returned to a suction of the compressor 105, and the working fluid can continue to be circulated in the heat transfer circuit.

[0056] FIG. 2 is a schematic diagram of an embodiment of an HVACR system 200 for heating and / or cooling a first process fluid using a compression cycle of a working fluid. The HVACR system 200 may include features similar to the HVACR system 100 in FIG. 1. For example, the HVACR system 200 includes a refrigerant circuit 202 that includes a compressor 205, a steam generation unit 210, expander(s) 232, and an evaporator 234 fluidly connected. The refrigerant circuit 202 of the HVACR system 200 heats a first process fluid PF1 in the steam generation unit and cools a second process fluid PF2 in the evaporator 234.

[0057] The steam generation unit 210 includes a plurality of heat exchangers 212, 214, 216. The working fluid in the refrigerant circuit 202 flows through the heat exchangers 212, 214, 216 in series. The first process fluid PF1 also separately flows through the heat exchangers 212, 214, 216. In each heat exchanger, the working fluid and the process fluid exchange heat without physically mixing. The steam generation unit heats liquid process fluid PF1' (e.g., liquid water) into superheated gaseous process fluid PF1'''' (e.g., superheated steam), which cools gaseous working fluid WF1' into subcooled liquid working fluid WF1''''. As shown in FIG. 2, the steam generation unit includes a first heat exchanger 212, a second heat exchanger 214, and a third heat exchanger 216. The first heat exchanger 212 can be referred to as liquid heat exchanger; the second heat exchanger 214 may be referred to as a mixed-phase heat exchanger; and the third heat exchanger 216 may be referred to as a gas heat exchanger.

[0058] Gaseous working fluid WF1' is cooled in the gas heat exchanger 216 to at or about the saturation temperature (e.g., de-superheated). The cooling in the gas heat exchanger 216 may partially condense the working fluid. The cooled working fluid WF1'' (e.g., gaseous working fluid, two-phase working fluid) is cooled in the mixed-phase heat exchanger 214 into liquid working fluid WF1''' (e.g., liquid single phase working fluid). The liquid working fluid WF1''' is cooled in the liquid heat exchanger 212 into subcooled liquid working fluid WF1''''. Liquid process fluid PF1' (e.g., water) is preheated in the liquid heat exchanger 212 to be at or about its saturation temperature. The heated liquid process fluid PF1'' is heated and boiled within the mixed-phase heat exchanger 214 into a gaseous process fluid PF1''' (e.g., steam). The gaseous process fluid PF1''' is then heated in the gas heat exchanger 216 into superheated gaseous process fluid PF1'''' (e.g., superheated steam).

[0059] The mixed-phase heat exchanger 214 includes a shell 260 and a plurality of heat exchange channels 262 (e.g., tubes) that extend through the shell 260. In the mixed-phase heat exchanger 214, the working fluid flows through the tube side (e.g., within the tubes 262 internal to the tubes 262) and the process fluid flows through shell side (e.g., external to the tubes 262). The HVACR system 200 can include a process fluid return line 204 for adjusting a liquid level LL of the process fluid in the shell 260. The process fluid return line 204 is configured to direct a portion of the liquid process fluid PF1* back to the liquid heat exchanger 212 to reduce the liquid level LL (e.g., cycle a portion of the liquid process fluid back through the liquid heat exchanger 212). The cycled liquid process fluid PF1* can be mixed with inlet liquid process fluid PF1' which then flows into the liquid heat exchanger 212.

[0060] The mixed-phase heat exchanger 214 includes a level controller 290 configured to control the liquid level LL of the process fluid in the shell 260. The level controller 290 may detect a liquid level LL of the process fluid in the shell 260 using a liquid level sensor 292 (e.g., a water level sensor). The level controller 290 can control the liquid level LL by controlling flow of the liquid process fluid PF1* through the process fluid return line 204. For example, the controller 290 may control the flow through the process fluid return line 204 by adjusting a valve 268 in the process fluid return line 204 (e.g., opening the valve, closing the valve, adjusting an opening of the valve) and / or adjusting operation of a pump 264 in the process fluid return line 204 (e.g., turn on, shut off, increase speed, decrease speed). In an embodiment, the process fluid return line 204 may include other components such as, but not limited to, a steam trap 266 to prevent steam from flowing through the process return line 204, an overflow reservoir (not shown) to allow for a temporary holding of the return process fluid liquid, etc.

[0061] The shell 260 of the mixed-phase heat exchanger includes a process fluid return port 270. The process fluid flows out of the shell 260 into the process fluid return line through the process fluid return port 270. As shown in FIG. 4, the process fluid return port 270 may be disposed in a lower portion of the shell 260 (e.g., in a bottom of the shell 260). In another embodiment, the process fluid return port 270 may be disposed at a desired maximum liquid level (e.g., a predetermined maximum liquid level) for the liquid level LL in the shell 260. In an embodiment, the level controller 290 can control the flow though the process fluid return port 270 (via controlling the flow through the process fluid return line 208) so that the liquid level is at a desired liquid level.

[0062] In an embodiment, the heat exchanger 214 may be configured to have a maximum liquid level setpoint (e.g., a predetermined maximum liquid level) and a minimum liquid level setpoint (e.g., a predetermined minimum liquid level). The controller 290 can be configured detect the liquid level LL with the liquid level sensor 292 and to control the liquid level LL to be at or between the maximum liquid level and the minimum liquid level. In one example, the liquid level sensor 292 is used to monitor the liquid level LL of the water in the shell 260. When the liquid level LL goes above the maximum liquid level setpoint, water is drained from the shell 260 through the process fluid return port 270 (e.g., controller 290 operates the process return line 204, flowrate of water into the process fluid return line 204 is increased). When the liquid level LL goes below the minimum liquid level setpoint, flow of water into the shell 260 is increased (e.g., flowrate of water (process fluid PF1'')into the shell 260 through the inlet(s) is increased, controller 290 operates the inlet water line and / or the process fluid return line 204 to increase the overall flow of water into the shell 260).

[0063] FIGS. 3A and 3B illustrate left and right perspective views of a heat exchanger 214 for a steam generation unit 310 that can be a shell and tube-type heat exchanger, according to one embodiment. The steam generation unit 310 is configured to receive a working fluid, such as a refrigerant, from a refrigerant circuit of a HVACR system (e.g., the refrigerant circuit of the HVACR system 100 in FIG. 1, the refrigerant circuit 202 of the HVACR system 200 in FIG. 2) and to generate a vapor (e.g., steam) from a process fluid.

[0064] In an embodiment, the heat exchanger 310 may be the heat exchanger 214 of the steam generation unit 210 in FIG. 2. For example, in the refrigerant circuit, the heat exchanger 310 is configured to receive preheated working fluid from a pre-heating / liquid heat exchanger (e.g., first heat exchanger 212) and receive de-superheated compressed working fluid from a superheating / gas heat exchanger (e.g., heat exchanger 216). In another embodiment, the heat exchanger 310 may be the steam generation unit 110 in FIG. 1. For example, in the refrigerant circuit, the heat exchanger 310 is configured to receive compressed superheated working fluid from a compressor (e.g., from compressor 105) and to discharge subcooled working fluid to an economizer (e.g., economizer) or to an expansion valve (e.g., expansion valve).

[0065] The heat exchanger 310 includes a shell 312 having a first end plate 314 and a second end plate 316, in which the shell 312, the first end plate 314, and the second end plate 316 define a volume for receiving a process fluid, such as water. The shell 312 includes a working fluid inlet 318 and a working fluid outlet 320. The working fluid inlet 318 is configured to receive the working fluid. The working fluid outlet 320 is configured to direct the conditioned working fluid, e.g., working fluid that has at least been de-superheated, condensed, and subcooled, out of the shell 312 (e.g., from the heat exchanger 310 to the next component in the refrigerant circuit). In some embodiments, the working fluid inlet 318 is located closer to the first end plate 314 (e.g., disposed in the first end plate 314) and the working fluid outlet 320 is located closer to the second end plate 316 (e.g., disposed in the second end plate 316), with the appreciation that the working fluid inlet 318 can be closer to the second end plate 316 and the working fluid outlet 320 can be closer to the first end plate 314.

[0066] A plurality of heat-exchanging channels (not shown) (e.g., heat exchange tubes) extend in the shell 312 between the first end plate 314 and the second end plate 316 in a longitudinal direction defined by a length L of the shell 312. One or more of the open ends of the heat-exchanging channels are attached to a tube sheet close to the first end plate 314 of the shell 312 and one or more of the open ends of the heat-exchanging channels are attached to a tube sheet close to the second end plate 316. The end plates 314, 316 include distribution chambers (not shown) for distributing the working fluid into the heat-exchanging channels, for re-distribution of the working fluid into the heat-exchanging channels, and for receiving and discharging the working fluid from the heat-exchanging channels. While inlet and outlet distribution chambers (not shown) are discussed herein as being on the first end plate 314 and the second end plate 316, such disclosure is not intended to be limiting. For example, in some embodiments, the inlet and outlet distribution chambers can be on the same end plate.

[0067] In some embodiments, the heat-exchanging channels are tube-like channels that include, but not limited to, tubes in a shell and tube heat exchanger, channels formed in heat exchanging plates in a plate heat exchanger in a stacked plate or bent plate arrangement, or the like. In some embodiments, the number and size of heat-exchanging channels can be determined based on the pressure drop in adjacent or lower rows of heat-exchanging channels, such that the number and size of the heat-exchanging channels is chosen to match the pressure drop in the adjacent or lower rows. In some embodiments, one or more tubes in the same pass can be designed or otherwise provided for performing different functions and / or heat exchange properties than tubes in the same pass. For example, in an embodiment, one or more of the tubes in the third pass can be designed or otherwise configured to de-superheat the refrigerant, whereas, the remaining tubes in the third pass can be designed or otherwise configured to completely de-superheat and condense the refrigerant. Similarly, one or more of the tubes in a second pass can be designed or otherwise configured to boil or vaporize the process fluid, e.g., water, while other tubes in the second pass can be designed or otherwise configured to superheat the vapor, e.g., steam.

[0068] The shell 312 further includes a process fluid inlet 322 and process fluid outlet(s) 324. The process fluid inlet 322 is configured to receive a process fluid (e.g., first process fluid PF1 in FIG. 2) from a water storage tank or water supply line. The process fluid outlet(s) 324 are configured to direct the conditioned process fluid, e.g., steam generated from water that has at least been vaporized and superheated, out of the shell 312, e.g., to a steam distribution header or steam storage. Typically, the process fluid inlet 322 is located closer to the bottom of the shell 312 for at least partially submerging at least some of the channels in the volume of the shell 312 to ensure proper heat exchange in the respective zones, as discussed herein, and the process fluid outlet(s) 324 are located closer to the top of the shell 312 to allow the vaporized process fluid to exit the volume of the shell 312.

[0069] In some embodiments, the shell and tube-type heat exchanger 310 can include additional components for controlling the steam generation by the steam generation unit. In some embodiments, the shell 312 can further include one or more sensors for monitoring the working condition of the shell 312. For example, the shell 312 can include a visual process fluid indicator 326 for visually monitoring the process fluid level in the shell 312, level sensor 328 for monitoring (e.g., digitally) the process fluid level in the shell 312 (e.g., using a float or fluid sensor), a process fluid limit switch 330 for preventing the over filling of the volume of the shell 312 with the process fluid, which can affect the effectiveness of the steam generation unit, drain port 332 for removing excess process fluid, and one or more of a pressure sensor or temperature sensor 334 to measure the pressure and / or temperature at different points in the shell, e.g., bottom, middle, and top, or the working fluid temperature in the first end plate 314 and / or second end plate 316, e.g., the temperature of the working fluid entering and exiting the heat exchanger.

[0070] FIG. 4 is a sectional side view of a heat exchanger 410 for a steam generation unit 400 of an HVACR system, according to an embodiment. The heat exchanger 410 is a shell and tube heat exchanger in FIG. 4. The steam generation unit 400, which can have the same or similar features as the steam generation unit 110 of FIG. 1, the steam generation unit 210 of FIG. 2, or the steam generation unit 310 of FIGS. 3A and 3B, is configured to receive a working fluid in a refrigerant circuit (e.g., in the HVACR system 100 as shown in FIG. 1, receive working fluid WF1' in the refrigerant circuit 204 of the HVACR system 200 in FIG. 2), and to generate a vapor (e.g., steam from a process fluid).

[0071] The heat exchanger 410 includes a shell 412 having a first end plate 414 and a second end plate 416. The shell 412, the first end plate 414, and the second end plate 416 define a volume 418 for receiving a process fluid PF. The shell 412 includes a working fluid inlet 420, a working fluid outlet 422, a process fluid inlet 424, and process fluid outlet(s) 426. The working fluid inlet 420 is configured to receive a working fluid WF in the refrigerant circuit. The working fluid outlet 422 is configured to discharge the conditioned WF (e.g., working fluid that has at least condensed and subcooled) out of the shell 412. In this embodiment, the working fluid inlet 420 is located closer to the first end plate 414 and the working fluid outlet 420 is located closer to the second end plate 416. However, it should be appreciated that this may different (e.g., inversed, in the same end plate, etc.) in other embodiments. The process fluid inlet 424 is configured to receive a process fluid PF into the shell (e.g., from a water source, from a water circuit, etc.). The process fluid outlets 426 are configured to discharge the conditioned process fluid (e.g., steam) from the shell 412. The heat exchanger 410 includes two process fluid outlets 426 in the illustrated embodiment. It should be appreciated that in another embodiment, the heat exchanger 410 may have one or more process fluid outlets 426 (e.g., one process fluid outlet, three process fluid outlets, etc.).

[0072] The heat exchanger 410 includes heat-exchanging channels 440 that extend in the shell 412 between the first end plate 414 and the second end plate 416 in a longitudinal direction defined by a length L of the shell to pass a working fluid WF for heat exchange with the process fluid PF inside the volume 418 of the shell 412. As shown in FIG. 4, the channels 440 can each be a respective heat exchange tube. The heat-exchanging channels 440 can each have an open end (e.g., a first open end) attached to a tube sheet 419A close to the first end plate 414 of the shell and another open end (e.g., a second open end) attached to a tube sheet 419B close to the second end plate 416. In some embodiments, a sealing ring, such as an elastic gasket or O-ring, can be used to seal the working fluid inlet 420 and / or the working fluid outlet 422 in their respective end plates.

[0073] The end plates 414, 416 include distribution chambers 442A, 442B, 442C, 442D for directing fluid from the working fluid inlet 420 through the heat-exchanging channels 440 to the working fluid outlet 422. The distribution chambers include an inlet distribution chamber 442A, an outlet distribution chamber 442D, and at least two intermediate distribution chambers 442B, 442C. Each of the heat-exchanging channels 440 extends between a pair of the distribution chambers 442A, 442B, 442C, 442D. Each of heat-exchanging channels 440 are configured to provide at least three passes of working fluid WF through the volume 418 of the heat exchanger 410. In the illustrated embodiment, the heat-exchanging channels 440 provide three passes of working fluid WF through the volume 418 of the heat exchanger 410 (e.g., working fluid has to pass across the volume 418 three times to flow from the working fluid inlet 420 to the working fluid outlet 422). As shown in FIG. 4, the heat-exchanging channels 440 are configured to include three passes between the end plates 414 and 416 through three heating zones (e.g., first heat exchange zone Z1 , second heat exchange zone Z2, third heat exchange zone Z3) formed in the volume 418.

[0074] For example, in an embodiment, the heat-exchanging channels 440 (e.g., tubes) are formed to include three separate (e.g., first pass, second pass, third pass) passes between the end plates 414, 416 (e.g., the channels 440 in each pass extend from first end plate 414 to the second end plate 416). The first pass of the heat-exchanging channels 440 is configured to preheat and / or nucleate the process fluid (e.g., water) in the volume 418 of the shell 412 and to subcool the working fluid inside the heat-exchanging channels 440. The first pass of the heat-exchanger channels 440 may also include subcool boiling of the process fluid. The second pass is configured to vaporize / boil the process fluid in the volume 418 of the shell 412 and to condense the working fluid inside the heat-exchanging channels 440. The third pass is configured to vaporize / boil and superheat the process fluid (e.g., vaporizing water into steam and superheating the steam) in the volume 418 of the shell 412 and to de-superheat the working fluid inside the heat-exchanging channels 440. The numbering of “first”, “second”, and “third” for the passes is with respect to the flow of process fluid over the heat-exchanging channels 440. The process fluid flowing across the heat-exchanging channels 440 of the first pass, then over the heat-exchanging channels 440 of the second pass, then over the heat-exchanging channels 440 of the third pass.

[0075] As such, in the illustrated embodiment, the configuration of the heat-exchanging channels 440 (e.g., tube configurations) are configured to include three passes through the three heat exchange zones Z1, Z2, Z3. As illustrated in FIG. 4, the heat exchanger 410 is configured to have the three heat exchange zones Z1, Z2, Z3, but not limited to, the first heat exchange zone Z1, which is a water pre-heating / refrigerant subcooling region that includes the first pass; a second heat exchange zone Z2, which is a water boiling / refrigerant condensation region that includes the second pass; and a third heat exchange zone Z3, which is a steam superheater / refrigerant desuperheater region that includes the third pass. The working fluid is provided in the zones that is countercurrent to the supply of the process fluid. The water pre-heating / refrigerant subcooling region (i.e., the first heat exchange zone Z1) can also include an amount of subcooling boiling and / or saturated boiling of the water and / or include an amount of condensing of the refrigerant. The steam superheater / refrigerant desuperheater region (i.e., the third heat exchange zone Z3) can also include an amount of condensing of the refrigerant. The heat exchanger 410 can be configured to have superheating of water only occur in the steam superheater / refrigerant desuperheater region (i.e., in the third heat exchange zone Z3) (e.g., all superheating of water occurs in the third heat exchange zone Z3).

[0076] For example, in an embodiment, the heat exchanger 410 is configured as a flooded heat exchanger in which a predetermined amount of tubes is covered by the liquid working fluid (e.g., liquid level LL is within the third zone Z3), such that the zones are provided sequentially to heat the process fluid from the first heat exchange zone Z1 to the second heat exchange zone Z2 to the third heat exchange zone Z3. Each zone of the heat exchanger 410 is configured such that the heat exchanger 410 and channels / tubes are configured considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water, and the like.

[0077] The steam generation unit 400 (e.g., heat exchanger 410) can be configured to have the liquid level LL disposed at a desired liquid level (e.g., at a predetermined target liquid level). As shown in FIG. 4, the steam generation unit 400 is configured to control the liquid level LL to be within the third heat exchange zone Z3 (e.g., the predetermined target liquid level is in the third heat exchange zone Z3). For example, the steam generation unit 400 is configured to control the liquid level LL to be below disposed between at least two rows of heat-exchanging channels 440 in the third pass (e.g., the predetermined is in between at least two rows of heat-exchanging channels 440 in the third pass). For example, the steam generation unit 400 is configured to control the liquid level LL to be below disposed below at least one row of heat-exchanging channels 440 in the third pass and above at least one row of heat-exchanging channels 440 in the third pass (e.g., the predetermined target liquid level is in the third heat exchange zone Z3). In an embodiment, the steam generation unit 410 can include a controller (shown shown) (e.g., controller 290 of the steam generation unit 200 in FIG. 2) can be configured to control the liquid level LL within the shell 412 to be at the desired / predetermined target liquid level. While specific paths associated with specific zones are discussed herein, such disclosure is not intended to be limiting. Rather, the path association with the specific zone can be controlled via the liquid level of the process fluid (e.g., of the water) in the heat exchanger 410 and / or dependent on the heat transfer characteristics necessary for vaporizing / boiling the water.

[0078] The tubes in each pass are configured to provide different functions and / or heat exchange properties of its respective pass. For example, the tubes in the first pass (e.g., one or more of the heat-exchanging channels 440 in the first zone Z1) are configured to preheat the water and to subcool the working fluid. For example, the tubes in the second pass (e.g., one or more of the heat-exchanging channels 440 in the second zone Z2) are configured for boiling / vaporizing the process fluid and for condensing the working fluid. For example, tubes in the third pass (e.g., one or more of the heat-exchanging channels 440 in the third zone Z3) are configured to de-superheat the refrigerant and to superheat the gaseous process fluid (e.g., superheat steam).

[0079] In some embodiments, one or more tubes in the same pass can be configured to provide different functions and / or heat exchange properties than tubes in the same pass. For example, in an embodiment, one or more of the tubes in the second pass (e.g., tubes in the second zone Z2) can be configured to boil / vaporize the process fluid, while the remaining tubes in the second pass can be configured to superheat the gaseous process fluid (e.g., to superheat steam). For example, in an embodiment, one or more of the tubes in the third pass (e.g., tubes in the third zone Z3) can be configured for de-superheating working fluid (e.g., de-superheating refrigerant), while the remaining tubes in the first pass can be configured to de-superheat and condense the refrigerant.

[0080] The tubes (e.g., heat-exchanging channels 440) can have features to provide the desired functions and / or heat exchange properties. Each tube can be configured to provide the desired type of heating of the process fluid (e.g., preheating of liquid working fluid, boiling / vaporization of liquid process fluid, superheating of gaseous process fluid) and the desired type of cooling of the working fluid (e.g., de-superheating of the gaseous working fluid, condensing of the gaseous working fluid, subcooling of the liquid working fluid). Such features include, but are not limited to, tube diameter, tube length, tube spacing (e.g., vertical spacing between tubes / tube rows, or the like), number of tubes (e.g., number of tubes in row, number of rows of said tubes), tube shape (e.g., overall shape, dimples, or the like), internal and / or external surface structures (e.g., fins, protrusions, or the like), surface texturing (e.g., surface to promote nucleation, surface to promote condensation, surface micro-structures, surface roughening, or the like), surface coatings (e.g., nucleation promoting surface, surfaces condensation promoting surface, hydrophilic / liquid-philic coating, hydrophobic / liquid-phobic coating, or the like), and the like.

[0081] For example, in an embodiment, tube(s) in in the first zone Z1 can have external features for heating liquid water (e.g., single-phase heating of water) and / or internal features for subcooling liquid working fluid (e.g., single-phase cooling of working fluid). In one example, the bottom row(s) of tube(s) in the first zone Z1 can be configured to have increased heat transfer coefficient (“HTC”) (e.g., to maximize heat transfer coefficient) by including external surface protrusions (e.g., fins) and / or relatively closer interspacing, and / or inner surface texturing (e.g., grooves, surface micro-structure). In one example, the bottom row(s) of tube(s) can also have a number of tubes and internal volume (e.g., diameter) to have a similar pressure drop as the upper row(s) of tube(s) in the first zone Z1 in which condensing of working fluid completes.

[0082] For example, in an embodiment, tube(s) in the second pass (e.g., in the second zone Z2) can have external features for boiling liquid water (e.g., phase-change heating of water) and / or internal features for condensing the working fluid (e.g., phase-change cooling of working fluid). In one example, the tubes in the second zone Z2 can have external surface texturing (e.g., roughening, grooves) that promotes water vaporization and inner surface texturing (e.g., roughening, grooves) that promotes condensation. Tube(s) in the second zone Z2 can be configured to have an increased internal HTC (e.g., maximize internal HTC) as the latent heat of boiling on external side provides relatively high HTC. For example, number of the tube(s), number of rows of tubes, and the internal volume (e.g., diameter) of tubes in the second zone Z2 can be selected based on providing a reduced pressure drop (e.g., to minimize pressure drop) and increased internal HTC.

[0083] For example, in an embodiment, tube(s) in the third pass (e.g., in the third zone Z2) can have external features for boiling water (e.g., phase-change heating of water) and superheating steam (e.g., single-phase heating of steam) and / or internal features for de-superheating partially gaseous working fluid (e.g., single-change cooling of working fluid). In one example, top row(s) of tubes in the third zone Z3 can be spaced apart for being spaced from liquid water within the shell 412 (e.g., spaced from the liquid level LL). Said top row(s) of tubes can have external features for superheating steam (e.g., fins, relatively closer interspacing than bottom row(s) in the third zone) and / or internal features for de-superheating process fluid. Condensing of the working fluid may occur in the bottom row(s) of tube(s) in the third zone Z3 (e.g., tubes disposed in the liquid water, tubes below the liquid level LL in the shell 412). The number of the tube(s) and the internal volume of the tubes (e.g., diameter) in the top row(s) of tubes in the third zone Z3 can be selected based on providing at or about the same pressure drop as the bottom row(s) of tube(s) in which the condensing occurs.

[0084] FIGS. 5A and 5B illustrate views of a steam generation unit 510 that can be a shell and tube-type heat exchanger (referred to as “heat exchanger 510” herein), according to another embodiment, in which certain features are hidden (not shown) for better understanding of the features. The steam generation unit 510, which can have the same or similar features as any of the steam generation units 110, 210, 310, 410 of FIGS. 1-4, is configured to receive a working fluid, such as a refrigerant, from a vapor-compression circuit of a HVACR system, such as, the HVACR system 100, 200 as shown in FIGS. 1, 2, and to generate a vapor, such as steam, from a process fluid. The heat exchanger 510 includes a shell 512 having a first end plate (not shown) and a second end plate (not shown), in which the shell 512, the first end plate, and the second end plate define a volume for receiving a process fluid, such as water. The shell 512 includes a working fluid inlet 518 and a working fluid outlet 520. The working fluid inlet 518 is configured to receive a working fluid, such as refrigerant, from a HVACR system, such as, a compression cycle of a vapor-compression circuit; and the working fluid outlet 520 is configured to direct the conditioned working fluid, e.g., working fluid that has at least been de-superheated, condensed, and subcooled, out of the shell 512. In this embodiment, the working fluid inlet 518 and the working fluid outlet 520 are located closer to the first end plate, as further discussed below.

[0085] A plurality of heat-exchanging channels 540 extend in the shell 512 between the first end plate and the second end plate in a longitudinal direction defined by a length L of the shell 512 to pass a working fluid for heat exchange with the process fluid inside the volume of the shell 512, e.g., along outer surfaces of the channels. One or more of the open ends of the heat-exchanging channels are attached to a tube sheet 519 close to the first end plate of the shell 512. The open ends form an inlet region and an outlet region on the tube sheet. The inlet region is typically configured to receive the working fluid and distribute the working fluid to the heat-exchanging channels. The outlet region is typically configured to direct the working fluid out of the heat-exchanging channels 540. In some embodiments, a sealing ring, such as, an elastic gasket or O-ring, can be used to separate the working fluid inlet 518 and the working fluid outlet 520, such that the working fluid inlet 518 and the working fluid outlet 520 are provided in a sealing engagement on the same tube sheet / end plate.

[0086] In an embodiment, the heat-exchanging channels 540 are tube-like channels that are in a bent tube configuration, such that the heat-exchanging channels are tube configurations 540 formed as a plurality of continuous tubes to make two or more passes, and in some embodiments, three, four, or more passes, within the shell 512. In some embodiments, the tube configurations 540 can be formed from a bent tube or from multiple tube sections that are joined by brazing to form the different passes, in which a plurality of tube configurations 540 are provided for forming the entirety of the two or more passes, e.g., tubes along the same horizontal plane. Generally, each of the tube configurations 540 starts at the inlet region of the tube sheet 519, runs along or across the shell 512 in the longitudinal direction defined by a length L, and then is bent or turned close to the second end of the shell 512 forming at least one bent section. The tube configurations 540 then run across the shell 512 in the longitudinal direction defined by the length L again, until the two or more passes are formed in which the other open ends of the tube configurations 540 end at the outlet region of the tube sheet 519, in which an additional at least one bent section is provided. As illustrated in FIGS. 5A and 5B, the tube configurations 540 are formed to have four passes.

[0087] For example, in an embodiment, the tube configurations 540 can be formed as continuous tubes such that the continuous tubes are bent or formed to include at least a third pass (Pass 01) between the end plates of the heat exchanger 510 for de-superheating the working fluid inside the tubes and boiling and superheating the process fluid, e.g., vaporizing water into steam and superheating the steam, in the volume of the shell 512; a second pass (Pass 02 and / or Pass 03) between the end plates for condensation of the working fluid inside the tube configurations 540 and vaporizing / boiling of the process fluid in the volume of the shell 512; and a first pass (Pass 04) between the end plates for subcooling the working fluid in the tube configurations 540 and preheating and / or nucleating the process fluid, e.g., water, in the volume of the shell 512. In some embodiments, one or more of the passes can include an additional pass. For example, in the illustrated embodiment, the second pass can include two passes, e.g., Pass 02 and Pass 03, or include a single pass, in which the outlet region would be provided on the tube sheet 519 close to the second end plate of the shell 512. As such, in the illustrated embodiment, the tube configurations 540 are designed and / or provided to include four passes through the three zones, e.g., Zone 1, Zone 2, Zone 3.

[0088] It should be understood that numbering of passes and numbering of heat exchange zones as used herein is for differentiating features and does not indicate a specific consecutive order of the passes / heat exchange zones. For example, “first pass”, “second pass”, and “third pass” may be sequential or may be non-consecutive passes. For example, “the first pass”, “the second pass”, and / or “the third pass” as described herein may each respectively include a single pass or two or more passes through its respective zone for the recited conditioning of the process fluid and / or working fluid.

[0089] As such, as illustrated in FIGS. 5A and 5B, the heat exchanger 510 is configured to have at least three heat exchange zones or regions including, but not limited to, a first zone, Zone 1; a second zone, Zone 2; and a third zone, Zone 3. First zone (Zone 1) is a water pre-heating / refrigerant subcooling region that includes the first pass (Pass 04) that is designed or otherwise configured to subcool the refrigerant and to bring the water temperature to saturated boiling temperature. Second zone (Zone 2) is a water boiling / refrigerant condensation region that includes the second pass (Pass 02 and / or Pass 03) that is designed or otherwise configured to maximize the steam generation rate. Third zone (Zone 3) is a steam superheater / refrigerant desuperheater region that includes the third pass (Pass 01) that is designed to de-superheat the refrigerant and to boil the water and / or superheat the steam. The working fluid is provided in the zones that are countercurrent to the supply of the process fluid. For example, in an embodiment, the heat exchanger 510 is configured as a flooded heat exchanger in which a predetermined amount of tubes are covered by the water, e.g., at water line 350 between Zone 2 and Zone 3, such that the zones are provided sequentially to heat the process fluid from the first heat exchange zone (Zone 1) to the second heat exchange zone (Zone 2) to the third heat exchange zone (Zone 3). Thus, each zone or region of the heat exchanger 510 is configured and / or designed such that the heat exchanger 510 and tube configurations 540 are designed or otherwise provided considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water. It is understood that in such design, the tube diameters of the tube configurations 540 can be different between the different zones to control / regulate the flow of the working fluid through the tube configurations 540. Moreover, while specific paths associated with specific zones are discussed herein, such disclosure is not intended to be limiting. Rather, the path association with the specific zone can be controlled via the water level in the heat exchanger 510 or dependent on the heat transfer characteristics necessary for vaporizing / boiling the water.

[0090] The shell 512 further includes a process fluid inlet 522 and process fluid outlet(s) 524. The process fluid inlet 522 is configured to receive a process fluid, such as water, from a water storage tank or water supply line; and the process fluid outlet(s) 524 are configured to direct the conditioned process fluid, e.g., steam generated from water that has at least been vaporized and superheated, out of the shell 512 to a steam distribution header or steam storage. Typically, the process fluid inlet 522 is located closer to the bottom of the shell 512 for at least partially flooding one or more of the channels in the volume of the shell 512 to ensure proper heat exchange in the respective zones, as discussed herein, and the process fluid outlet(s) 524 are located closer to the top of the shell 512 to allow the vaporized process fluid to exit the volume of the shell 512 at a top of the shell 512. In some embodiments, the process fluid inlet 522 can include a diffuser or distributor 523 that extends along the length of the shell for distributing the process fluid in the volume of the shell 512.

[0091] In some embodiments, the shell and tube-type heat exchanger 510 can include additional components for controlling the steam generation by the steam generation unit. In some embodiments, the shell 512 can further include one or more sensors for monitoring the working condition of the shell 512. For example, the shell 512 can include a visual process fluid indicator for visually monitoring the process fluid level in the shell 512, level sensor for digitally monitoring the process fluid level in the shell 512, for example, using a float or fluid sensor, a process fluid limit switch 530 for preventing the over filling of the volume of the shell 512 with the process fluid, which can affect the effectiveness of the steam generation unit, drain port for removing excess process fluid, and one or more of a pressure sensor or temperature sensor to measure the pressure and / or temperature at different points in the shell, e.g., bottom, middle, and top, or the working fluid temperature in the first end plate and / or second end plate, e.g., the temperature of the working fluid entering and exiting the heat exchanger.

[0092] Operation of the steam generation unit 510 is discussed below, in which the working fluid can be any refrigerant, and, in some embodiments, a refrigerant selected from one or more of R1234yf, R134a, R1234ze(E), R1234ze(Z), R245fa, R1233zd(E), R1336mzz(Z), R365mfc, R600a, R600, R601, R717, R744, R718, and R1224yd(Z) and the process fluid is water. The water can enter the steam generation unit 510 with 1 to 2 ⁰C subcooled condition and the water needs to be boiled / vaporized to generate steam by boiling and superheating, e.g., via convection heat transfer phenomena, and leave the shell 512 in a 1 to 2 ⁰C superheated steam state.

[0093] Initially, water may be directed into the shell 512 through the process fluid inlet 522, then flow in the longitudinal direction defined by the length L of the shell 512 and flood the volume of the shell 512, e.g., to cover specific portions of the tube configurations 540 to a predetermined water level at water level 550. The working fluid can then be directed to the working fluid inlet 518 which is configured to supply the working fluid to the open ends of the tube configurations 540A, 540B, e.g., via a header or by supplying the working fluid to the entirety of the inlet end of the tube sheet, e.g., inlet region. The working fluid can be a refrigerant with high critical temperature, in which condensation occurs above 105⁰C, in which the selection of the refrigerant can further depend on the water boiling pressure. As the high temperature refrigerant is supplied to the tube configurations 540 at the inlet 518, the refrigerant flows along the third pass (Pass 01) in Zone 3 in which one or more of the tube bundles, e.g., rows of the tube configurations 540, are configured for de-superheating the refrigerant inside the tubes by at least performing one or more of boiling the water and superheating the steam in the volume of the shell 512. In some embodiments, in Zone 3, the shell and tube configurations 540 are configured to de-superheat the refrigerant with minimal pressure drop followed by condensation, e.g., refrigerant quality from 1 to 0.7), while the water quality increases from x = 0.7 to 1 with superheating the steam. As the refrigerant passes through Zone 3, the refrigerant in the second pass (Pass 02 and / or Pass 03) in Zone 2 is used to condense the refrigerant inside the tube configurations 540 and vaporize / boil the water in the volume of the shell 512. In some embodiments, in Zone 2, the shell and tube configurations 540 are configured for intense water boiling, e.g., steam quality increases from x = 0.1 to 0.8, and the refrigerant condenses, e.g., refrigerant quality decreases from x = 0.9 to 0.2. After the refrigerant passes through Zone 2, the condensed refrigerant passes through the first pass (Pass 04) in Zone 1 for subcooling the refrigerant in the tube configurations 540 and preheating and / or nucleating the water in the volume of the shell 512. As such, the water is preheated and / or nucleated in Zone 1, vaporized / boiled in Zone 2, and further boiled and / or superheated in Zone 3 to generate 1 to 2 ⁰C superheated steam.

[0094] In some embodiments, the water level in the volume of the shell 512 can be controlled to maintain the water level at water level 550 to ensure adequate or proper coverage of specific portions of the tube configurations 540 to ensure production and superheating of the steam by the steam generation unit 510, e.g., between Zone 2 and Zone 3. As such, the steam generation unit 510 can be configured to have an optimized R245fa or R1233zd(E) refrigerant condenser design of 600kW capacity with steam generation rate of 945kg / hr at 1 bar pressure using refrigerant (R245fa or R1233zd(E)), in which a minimum of 5 to 8 ⁰C temperature difference is maintained between water boiling temperature and refrigerant temperature.

[0095] FIGS. 6-8C illustrate various embodiments of the plurality of channels according to different embodiments. It is appreciated that certain features as disclosed herein can be used with other embodiments without changing the scope of the disclosure. Furthermore, while certain features as discussed below with respect to specific features, it is understood that the resulting steam generation unit can have any of the features of the steam generation units discussed above, e.g., any of the steam generation units 110, 210, 310, 410, 510 of FIGS. 1-5B, and are not discussed below to better understand the disclosure.

[0096] FIG. 6 illustrates a side view of a steam generation unit 610 that can be a shell and tube-type heat exchanger, according to an embodiment, in which certain features are hidden (not shown) for better understanding of the features. The steam generation unit 610, which can have the same or similar features as any of the steam generation units 110, 210, 310, 410, 510 of FIGS. 1-5B, is configured to receive a working fluid, such as a refrigerant, from a vapor-compression circuit of a HVACR system, such as, the HVACR systems 100 or 200 as shown in FIGS. 1 and 2, and to generate a vapor, such as steam, from a process fluid. The heat exchanger 610 includes a shell (not show) having a first end plate 614 and a second end plate 616, in which the shell, the first end plate 614, and the second end plate 616 define a volume for receiving a process fluid, such as water. The shell includes a working fluid inlet 618 and a working fluid outlet 620. The working fluid inlet 618 is configured to receive a working fluid, such as refrigerant, from a HVACR system, such as, a compression cycle of a vapor-compression circuit; and the working fluid outlet 620 is configured to direct the conditioned working fluid, e.g., working fluid that has at least been de-superheated, condensed, and subcooled, out of the shell. In this embodiment, the working fluid inlet 618 is located closer to the first end plate 614 and the working fluid outlet 620 is located closer to the second end plate 616.

[0097] A plurality of heat-exchanging channels 640 extend in the shell between the first end plate 614 and the second end plate 616 in a longitudinal direction defined by a length L of the shell to pass a working fluid for heat exchange with the process fluid inside the volume of the shell, e.g., along outer surfaces of the channels. One or more of the open ends of the heat-exchanging channels are attached to a tube sheet 619 close to the first end plate 614 of the shell and one or more of the open ends of the heat-exchanging channels are attached to a tube sheet 619 close to the second end plate 616. The open ends form an inlet region and an outlet region on the respective tube sheets. The inlet region is typically configured to receive the working fluid and distribute the working fluid to the heat-exchanging channels 640. The outlet region is typically configured to direct the working fluid out of the heat-exchanging channels 640. In some embodiments, a sealing ring, such as, an elastic gasket or O-ring, can be used to seal the working fluid inlet 618 and / or the working fluid outlet 620 in their respective end plates and tube sheets.

[0098] The heat-exchanging channels 640 are tube-like channels that are in a bent tube configuration, such that the heat-exchanging channels are tube configurations 640 formed as a plurality of continuous tubes to make two or more passes, and in some embodiments, three, four, or more passes, within the shell. In some embodiments, the tube configurations 640 can be formed from a plurality of bent tubes or from multiple tube sections that are joined by brazing to form the different passes, in which a plurality of tube configurations 640 are provided for forming the entirety of the two or more passes. Generally, each of the tube configurations 640 starts at the inlet region of the tube sheet 619, runs along or across the shell in the longitudinal direction defined by a length L, and then is bent or turned close to the second end of the shell forming at least one bent section. The tube configurations 640 then run across the shell in the longitudinal direction defined by the length L again, until the two or more passes are formed in which the other open ends of the tube configurations 640 end at the outlet region of the tube sheet 619, in which an additional at least one bent section is provided. As illustrated in FIG. 6, the tube configurations 640 are formed to have three passes.

[0099] For example, in an embodiment, the tube configurations 640 can be formed as continuous tubes such that the continuous tubes are bent or formed to include at least a third pass between the end plates 614 and 616 of the heat exchanger 610 for de-superheating the working fluid inside the tubes and boiling and superheating the process fluid, e.g., vaporizing water into steam and superheating the steam, in the volume of the shell; a second pass between the end plates 614 and 616 for condensation of the working fluid inside the tube configurations 640 and vaporizing / boiling of the process fluid in the volume of the shell; and a first pass between the end plates 614 and 616 for subcooling the working fluid in the tube configurations 640 and preheating and / or nucleating the process fluid, e.g., water, in the volume of the shell. As such, in the illustrated embodiment, the tube configurations 640 are designed and / or provided to include three passes through the three zones, e.g., Zone 1, Zone 2, Zone 3.

[0100] As such, as illustrated in FIG. 6, the heat exchanger 610 is configured to have at least three heat exchange zones or regions including, but not limited to, a first zone, a second zone, and a third zone. The first zone is a water pre-heating / refrigerant subcooling region that includes the first pass. The second zone is a water boiling / refrigerant condensation region that includes the second pass. The third zone is a steam superheater / refrigerant desuperheater region that includes the third pass. The working fluid is provided in the zones that are countercurrent to the supply of the process fluid. For example, in an embodiment, the heat exchanger is configured as a flooded heat exchanger in which a predetermined amount of tubes is covered by the water, e.g., between Zone 2 and Zone 3, such that the zones are provided sequentially to heat the process fluid from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone. Thus, each zone or region of the heat exchanger 610 is configured and / or designed such that the heat exchanger 610 and tube configurations 640 are designed or otherwise provided considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water. While specific paths associated with specific zones are discussed herein, such disclosure is not intended to be limiting. Rather, the path association with the specific zone can be controlled via the water level in the heat exchanger 610 or dependent on the heat transfer characteristics necessary for vaporizing / boiling the water.

[0101] In some embodiment heat transfer fins 645 can be provided on the tube configurations 640 at various locations to increase the heat transfer between the tube configurations 640 and the process fluid, e.g., water. For example, as illustrated in FIG. 6, in an embodiment, heat transfer fins 645 are provided in the third zone, e.g., third pass or first row (or first and second top rows), and the first zone, e.g., first pass or lowest row, to increase the steam side heat transfer coefficient between the tube configurations 640 and the process fluid. Such disclosure, however, is not intended to be limiting. It is understood that the heat transfer fins 645 can be placed on the tube configurations in different zones and / or rows to provide the necessary heat transfer between the tube configurations 640 and the process fluid.

[0102] FIG. 7 illustrates another embodiment of heat transfer fins 745 provide on a plurality of heat-exchanging channels 740 for a steam generation unit 710. The plurality of heat-exchanging channels 740 extend in the shell between the first end plate and the second end plate in a longitudinal direction defined by a length L of the shell to pass a working fluid for heat exchange with the process fluid inside the volume of the shell. One or more of the open ends of the heat-exchanging channels are attached to a tube sheet 719 close to an end plate of the shell. The open ends form an inlet region and an outlet region on the tube sheet 719. The inlet region is typically configured to receive the working fluid and distribute the working fluid to the heat-exchanging channels 740. The outlet region is typically configured to direct the working fluid out of the heat-exchanging channels 740. In an embodiment, the inlet region and outlet region can include a distribution header for supplying the working fluid to the plurality of heat-exchanging channels 740 and a distribution header for receiving the conditioned working fluid from the heat-exchanging channels 740.

[0103] The heat-exchanging channels 740 are tube-like channels that are in a bent tube configuration, such that the heat-exchanging channels are tube configurations 740 formed as a plurality of continuous tubes to make two or more passes, and in some embodiments, three, four, or more passes, within the shell. In some embodiments, the tube configurations 740 can be formed from a plurality of bent tubes or from multiple tube sections that are joined by brazing to form the different passes, in which a plurality of tube configurations 740 are provided for forming the entirety of the two or more passes. Generally, each of the tube configurations 740 starts at the inlet region of the tube sheet 719, runs along or across the shell in the longitudinal direction defined by a length L, and then is bent or turned close to the second end of the shell forming at least one bent section. The tube configurations 740 then run across the shell in the longitudinal direction defined by the length L again, until the two or more passes are formed in which the other open ends of the tube configurations 740 end at the outlet region of the tube sheet 719. As illustrated in FIG. 7, the tube configurations 740 are formed to have six passes.

[0104] For example, in an embodiment, the tube configurations 740 can be formed as continuous tubes such that the continuous tubes are bent or formed to include at least a third pass between the end plates of the heat exchanger for de-superheating the working fluid inside the tubes and boiling and superheating the process fluid, e.g., vaporizing water into steam and superheating the steam, in the volume of the shell; a second pass between the end plates for condensation of the working fluid inside the tube configurations 740 and vaporizing / boiling of the process fluid in the volume of the shell; and a first pass between the end plates for subcooling the working fluid in the tube configurations 740 and preheating and / or nucleating the process fluid, e.g., water, in the volume of the shell. As such, in the illustrated embodiment, the tube configurations 740 are designed and / or provided to include at least three passes through the three zones, e.g., Zone 1, Zone 2, Zone 3.

[0105] As such, as illustrated in FIG. 7, the heat exchanger 710 is configured to have at least three heat exchange zones or regions including, but not limited to, a first zone, a second zone, and a third zone. The first zone is a water pre-heating / refrigerant subcooling region that includes the first pass and the second pass. The second zone is a water boiling / refrigerant condensation region that includes the third pass and the fourth pass. The third zone is a steam superheater / refrigerant desuperheater region that includes the fifth pass and the sixth pass. The working fluid is provided in the zones that are countercurrent to the supply of the process fluid. For example, in an embodiment, the heat exchanger is configured as a flooded heat exchanger in which a predetermined amount of tubes is covered by the water, e.g., between Zone 2 and Zone 3, such that the zones are provided sequentially to heat the process fluid from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone. Thus, each zone or region of the heat exchanger 710 is configured and / or designed such that the heat exchanger 710 and tube configurations 740 are designed or otherwise provided considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water. While specific paths associated with specific zones are discussed herein, such disclosure is not intended to be limiting. Rather, the path association with the specific zone can be controlled via the water level in the heat exchanger 710 or dependent on the heat transfer characteristics necessary for vaporizing / boiling the water.

[0106] In this embodiment, the heat transfer fins 745 are continuous heat transfer plates that are provided on the tube configurations 740 to increase the heat transfer between the various passes of the tube configurations 740 and zones and the process fluid, e.g., water. For example, as illustrated in FIG. 7 in an embodiment, heat transfer plates 745 can be provided between the third zone and the first zone to increase the steam side heat transfer coefficient between the tube configurations 740 and the process fluid and to distribute the heat within the shell. Such disclosure, however, is not intended to be limiting. It is understood that the heat transfer plates 745 can be placed as staggered plates or split fin plates joining two or more rows of the tube configurations 740.

[0107] FIGS. 8A, 8B, 8C illustrate other embodiments of a plurality of heat-exchanging channels 840 for a steam generation unit 810. The plurality of heat-exchanging channels 840 extend in the shell between the first end plate and the second end plate in a longitudinal direction defined by a length L of the shell to pass a working fluid for heat exchange with the process fluid inside the volume of the shell. One or more of the open ends of the heat-exchanging channels are attached to a tube sheet 819 close to an end plate of the shell. The open ends form an inlet region and an outlet region on the tube sheet 819. The inlet region is typically configured to receive the working fluid and distribute the working fluid to the heat-exchanging channels 840. The outlet region is typically configured to direct the working fluid out of the heat-exchanging channels 840. In an embodiment, the inlet region and outlet region can include a distribution header for supplying the working fluid to the plurality of heat-exchanging channels 840 and a distribution header for receiving the conditioned working fluid from the heat-exchanging channels 840.

[0108] The heat-exchanging channels 840 are tube-like channels that are in a bent tube configuration, such that the heat-exchanging channels are tube configurations 840 formed as a plurality of continuous tubes to make two or more passes, and in some embodiments, three, four, or more passes, within the shell, e.g., along outer surfaces of the channels. In some embodiments, the tube configurations 840 can be formed from a plurality of bent tubes or from multiple tube sections that are joined by brazing to form the different passes, in which a plurality of tube configurations 840 are provided for forming the entirety of the two or more passes. Generally, each of the tube configurations 840 starts at the inlet region of the tube sheet 819, runs along or across the shell in the longitudinal direction defined by a length L, and then is bent or turned close to the second end of the shell forming at least one bent section. The tube configurations 840 then run across the shell in the longitudinal direction defined by the length L again, until the two or more passes are formed in which the other open ends of the tube configurations 840 end at the outlet region of the tube sheet 819. As illustrated in FIGS. 8A, 8B, 8C, the tube configurations 840 are formed to have six passes.

[0109] For example, in an embodiment, the tube configurations 840 can be formed as a plurality of continuous tubes such that the continuous tubes are bent or formed to include at least a third pass between the end plates of the heat exchanger for de-superheating the working fluid inside the tubes and boiling and superheating the process fluid, e.g., vaporizing water into steam and superheating the steam, in the volume of the shell; a second pass between the end plates for condensation of the working fluid inside the tube configurations 840 and vaporizing / boiling of the process fluid in the volume of the shell; and a first pass between the end plates for subcooling the working fluid in the tube configurations 840 and preheating and / or nucleating the process fluid, e.g., water, in the volume of the shell. As such, in the illustrated embodiment, the tube configurations 840 are designed and / or provided to include three passes through the three zones, e.g., Zone 1, Zone 2, Zone 3.

[0110] As such, as illustrated in FIGS. 8A, 8B, 8C, the heat exchanger 810 is configured to have at least three heat exchange zones or regions including, but not limited to, a first zone, a second zone, and a third zone. The first zone is a water pre-heating / refrigerant subcooling region that includes the first and second pass. The second zone is a water boiling / refrigerant condensation region that includes the third and fourth pass. The third zone is a steam superheater / refrigerant desuperheater region that includes the fifth and sixth pass. The working fluid is provided in the zones that are countercurrent to the supply of the process fluid. For example, in an embodiment, the heat exchanger is configured as a flooded heat exchanger in which a predetermined amount of tubes is covered by the water, e.g., between Zone 2 and Zone 3, such that the zones are provided sequentially to heat the process fluid from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone. Thus, each zone or region of the heat exchanger 810 is configured and / or designed such that the heat exchanger 810 and tube configurations 840 are designed or otherwise provided considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water. While specific paths associated with specific zones are discussed herein, such disclosure is not intended to be limiting. Rather, the path association with the specific zone can be controlled via the water level in the heat exchanger 810 or dependent on the heat transfer characteristics necessary for vaporizing / boiling the water.

[0111] In these embodiments, one or more of the passes of the tube configurations 840 are formed as zig-zag tubes to enhance turbulent flow inside the tube configurations for better heat transfer, e.g., increases the heat transfer coefficient, with the water side which results in generating more vapor and better water refilling. As illustrated in FIG. 8A, a number of passes in the top rows and bottom rows of the tube configurations 840 can have the zig-zag formation, e.g., in Zones 3 and 1 for more effective heat transfer. In some embodiments, as seen in FIGS. 8B and 8C, which are top views of the tube configurations 840, the tube configurations 840 can have the zig-zag formation an in-line arrangement or in a staggered arrangement for the respective passes.

[0112] FIGS. 9A, 9B, 9C illustrate views of a steam generation unit 910 that can be a shell and tube-type heat exchanger, according to one embodiment, in which certain features are hidden (not shown) for better understanding of the features. The steam generation unit 910, which can have the same or similar features as any of the steam generation units 110, 210, 310, 410, 510, 610, 710, 810 of FIGS. 1-8C, is configured to receive a working fluid, such as a refrigerant, from a vapor-compression circuit of a HVACR system, such as, the HVACR systems 100 or 200 as shown in FIGS. 1 and 2, and to generate a vapor, such as steam, from a process fluid.

[0113] The heat exchanger 910 includes a shell 912 having a first end plate 914 and a second end plate 916, in which the shell 912, the first end plate 914, and the second end plate 916 define a volume for receiving a process fluid, such as water. The shell 912 includes a working fluid inlet 918 and a working fluid outlet 920. The working fluid inlet 918 is configured to receive a working fluid, such as refrigerant, from a HVACR system, such as, a compression cycle of a vapor-compression circuit; and the working fluid outlet 920 is configured to direct the conditioned working fluid, e.g., working fluid that has at least been de-superheated, condensed, and subcooled, out of the shell 912. In this embodiment, the working fluid inlet 918 and the working fluid outlet 920 are located on the same end plate 914, as further discussed below.

[0114] A plurality of heat-exchanging channels 940 extend in the shell 912 between the first end plate 914 and the second end plate 916 in a longitudinal direction defined by a length L of the shell 912 to pass a working fluid for heat exchange with the process fluid inside the volume of the shell 912, e.g., along outer surfaces of the channels. One or more of the inlet ends of the heat-exchanging channels are attached to the first end plate 914 of the shell 912, e.g., via a distribution header or manifold 960, to form a common inlet header and one or more outlet ends of the heat-exchanging channels are attached to the first end plate 914 to form a common outlet header. The inlet header is typically configured to receive the working fluid and distribute the working fluid to the heat-exchanging channels. The outlet header is typically configured to direct the working fluid out of the heat-exchanging channels 940.

[0115] As illustrated in FIGS. 9B and 9C, the distribution header or manifold 960 can be provided in various locations. In an embodiment, as illustrated in FIG. 9B, the distribution header or manifold 960 is provided on an outer surface of the end plate 914 such that the distribution header or manifold 960 is configured to be connected to each channel of each of the plates having the heat-exchanging channels 940. In another embodiment, as illustrated in FIG. 9C, the distribution heard or manifold 960 is provided inside the shell 912, e.g., along an inner surface of the end plate 914, such that the distribution header or manifold 960 is configured to be connected to each of the heat-exchanging channels 940.

[0116] In an embodiment, the heat-exchanging channels 940 are tube-like channels that are in a heat exchanging stacked plate configuration, such that the heat-exchanging channels 940 are formed in plates 942 that are formed from a plurality of continuous plates that are stacked to form each of the heat-exchanging channels 940 forming two or more passes, and in some embodiments, three, four, or more passes, within the shell 912.

[0117] In some embodiments, the heat-exchanging channels 940 can be formed from a bent plate or from multiple stacked plate sections that are joined by brazing to form the different branches, e.g., channels in the same pass, in which a plurality of plates 942 are provided for forming the entirety of the two or more passes. The plate(s) can be roll bond panels, spiral-shaped plates, and / or pillow-plates and can be formed from stainless steel, aluminum, or the like.

[0118] Generally, each of the stacked plates 942 are formed to have heat-exchanging channels 940 that start at the inlet region, run along or across the shell 912 in the longitudinal direction defined by a length L, and then turned close to the second end of the shell 912 forming at least one bending section or turn section. The heat-exchanging channels 940 then run across the shell 912 in the longitudinal direction defined by the length L again, until the two or more passes are formed in which the other open ends of the heat-exchanging channels 940 end at the outlet region, in which an additional at least one bending section or turn section is provided. As illustrated in FIGS. 9A, 9B, 9C, the heat-exchanging channels 940 are formed to have eight passes, but such disclosure is not intended to be limiting, as a number of different passes can be used, as discussed above.

[0119] For example, in an embodiment, the plates 942 can be formed as stacked plates having continuous heat-exchanging channels 940 that are formed to include at least a third pass (Pass 01), a second pass (Pass 02), and a first pass (Pass 03) between the end plates of the heat exchanger 910. The third pass (Pass 01) is configured for de-superheating the working fluid inside the tubes and boiling and superheating the process fluid, e.g., vaporizing water into steam and superheating the steam, in the volume of the shell 912. The second pass (Pass 02) is configured for condensation of the working fluid inside the heat-exchanging channels 940 and vaporizing / boiling of the process fluid in the volume of the shell 912. The first pass (Pass 03) is configured for subcooling the working fluid in the heat-exchanging channels 940 and preheating and / or nucleating the process fluid, e.g., water, in the volume of the shell 912. In some embodiments, one or more of the passes can include an additional pass. For example, in the illustrated embodiment, the third pass and the second pass can include two or more passes or include a single pass. As such, in the illustrated embodiment, the heat-exchanging channels 940 are designed and / or provided to include eight passes through the three zones, e.g., Zone 1, Zone 2, Zone 3, which is not intended to be limiting in scope, but for understanding of the disclosure.

[0120] As such, as illustrated in FIG. 9A, the heat exchanger 910 is configured to have at least three heat exchange zones or regions including, but not limited to, a first zone, Zone 1; a second zone, Zone 2; and a third zone, Zone 3. The first zone is a water pre-heating / refrigerant subcooling region that includes the first pass (Pass 03) that is designed or otherwise configured to subcool the refrigerant with minimal pressure drop of refrigerant and to bring the water temperature to saturated boiling temperature. The second zone, Zone 2, is a water boiling / refrigerant condensation region that includes the second pass (Pass 02) that is designed or otherwise configured to maximize the steam generation rate. The third zone, Zone 3, is a steam superheater / refrigerant desuperheater region that includes the third pass (Pass 01) that is designed to de-superheat the refrigerant and to boil the water and / or superheat the steam. The working fluid is provided in the zones that are countercurrent to the supply of the process fluid. For example, in an embodiment, the heat exchanger is configured as a flooded heat exchanger in which a predetermined amount of tubes are covered by the water, e.g., between Zone 2 and Zone 3, such that the zones are provided sequentially to heat the process fluid from the first heat exchange zone (Zone 1) to the second heat exchange zone (Zone 2) to the third heat exchange zone (Zone 3). Thus, each zone or region of the heat exchanger 910 is configured and / or designed such that the heat exchanger 910 and heat-exchanging channels 940 (and plates 942) are designed or otherwise provided considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water. It is understood that in such design, the channel diameters of the heat-exchanging channels 940 can be different between the different zones. In some embodiments, the channels can also be provided as a tapered design with narrowing diameter through one or more of the passes.

[0121] The shell 912 further includes a process fluid inlet 922 and process fluid outlet 924. The process fluid inlet 922 is configured to receive a process fluid, such as water, from a water storage tank or water supply line; and the process fluid outlet 924 is configured to direct the conditioned process fluid, e.g., steam generated from water that has at least been vaporized and superheated, out of the shell 912 to a steam distribution header or steam storage. Typically, the process fluid inlet 922 is located closer to the bottom of the shell 912 for at least partially flooding one or more of the channels in the volume of the shell 912 to ensure proper heat exchange in the respective zones, as discussed herein, and the process fluid outlet 924 is located closer to the top of the shell 912 to allow the vaporized process fluid to exit the volume of the shell 912 at a top of the shell 912. In some embodiments, the process fluid inlet 922 can include a diffuser or distributor 923 for distributing the process fluid in the volume of the shell 912.

[0122] In some embodiments, the shell and tube-type heat exchanger 910 can include additional components for controlling the steam generation by the steam generation unit. In some embodiments, the shell 912 can further include one or more sensors for monitoring the working condition of the shell 912. For example, the shell 912 can include a visual process fluid indicator for visually monitoring the process fluid level in the shell 912, level sensor for digitally monitoring the process fluid level in the shell 912, for example, using a float or fluid sensor, a process fluid limit switch for preventing the over filling of the volume of the shell 912 with the process fluid, which can affect the effectiveness of the steam generation unit, drain port for removing excess process fluid, and one or more of a pressure sensor or temperature sensor to measure the pressure and / or temperature at different points in the shell, e.g., bottom, middle, and top, or the working fluid temperature in the first end plate and / or second end plate, e.g., the temperature of the working fluid entering and exiting the heat exchanger.

[0123] FIGS. 10A, 10B, 10C, 11, 12A, 12B, 13A, 13B illustrate various embodiments of the plurality of channels according to different embodiments. It is appreciated that certain features as disclosed herein can be used with other embodiments without changing the scope of the disclosure. Furthermore, while certain features as discussed below with respect to specific features, it is understood that the resulting steam generation unit can have any of the features as discussed above with respect to any of the steam generation units discussed above, e.g., steam generation units 110, 210, 310, 410, 510, 610, 710, 810, 910 of FIGS. 1-9C, and are not discussed below to better understand the disclosure.

[0124] FIGS. 10A-10C illustrate various plate designs for a stacked plate configuration 1042 that can be used with any of the steam generation units, as discussed above. It is understood that different configurations can be used to provide the efficient heat transfer coefficient for vaporizing the process fluid, e.g., water, based on the heat available from the working fluid, e.g., refrigerant.

[0125] As illustrated in FIG. 10A, a plate 1042 of a plurality of plates can each include heat-exchanging channels 1040 that branch from the common inlet from working fluid inlet 1018. As such, the third pass, Pass 01, can include multiple channels that extend from the inlet to provide increased heat transfer area and / or to reduce pressure drop in the plurality of channels. As illustrated in FIG. 10A, heat-exchanging channels 1040 and the shell of the heat generation unit can be designed and / or configured to include at least four zones. The first zone includes Pass 04 for water pre-heating and boiling and refrigerant condensation and subcooling existing at a common outlet at working fluid outlet 1020. The second zone includes Pass 03 for water boiling and refrigerant condensation. The third zone includes Pass 02 for water boiling and refrigerant de-superheating and condensation. The fourth zone includes Pass 01 for steam superheating and refrigerant de-superheating.

[0126] FIG. 10B illustrates a plate 1042 of a plurality of plates that includes horizontal and vertical heat-exchanging channels (or sections). In an embodiment, the plurality of heat-exchanging channels can include an inlet that branches to form horizontal channels to form the first pass and then branches to form vertical channels through the different zones formed by the heat-exchanging channels 1040 and the shell of the steam generation unit. As illustrated in FIG. 10B, heat-exchanging channels 1040 and the shell of the heat generation unit can be designed and / or configured to include at least three zones, in which the first zone includes vertical channels and a horizontal channel for water pre-heating and boiling and refrigerant condensation and subcooling and for exiting the conditioned refrigerant; the second zone that includes vertical channels (and / or horizontal channels) for water boiling and refrigerant de-superheating and condensation; and the third zone that includes horizontal channels and vertical channels for steam superheating and refrigerant de-superheating.

[0127] FIGS. 10C-10I illustrates a plate 1042 of a plurality of plates that includes fins 1045 for providing additional heat transfer coefficient properties for the plate. As illustrated in FIGS. 10C-10I, the fins 1045 can be provided at different angles and shapes to increase the heat transfer area for the plurality of heat-exchanging channels 1040.

[0128] FIGS. 11A and 11B illustrate a plate design for heat-exchanging channels 1140 that can be used with any of the steam generation units, as discussed above, in which FIG. 11B illustrates a partial view of the plate 1142. It is understood that different configurations can be used to provide the efficient heat transfer coefficient for vaporizing the process fluid, e.g., water, based on the heat available from the working fluid, e.g., refrigerant. In this embodiment, in order to reduce the number of total stacked plates inside the shell of the steam generation unit, one or more of the plates having the heat-exchanging channels 1140 is bent to form the multiple channels for the passes for the heat-exchanging channels 1140.

[0129] The steam generation unit 1110 is configured to receive a working fluid, such as a refrigerant, from a vapor-compression circuit of a HVACR system, such as, the HVACR systems 100 or 200 as shown in FIGS. 1 and 2, and to generate a vapor, such as steam, from a process fluid. The steam generation unit 1110 includes a shell 1112 having a first end plate 1114 and a second end plate 1116, in which the shell 1112, the first end plate 1114, and the second end plate 1116 define a volume for receiving a process fluid, such as water. The shell includes a working fluid inlet 1118 and a working fluid outlet 1120. The working fluid inlet 1118 is configured to receive a working fluid, such as refrigerant, from a HVACR system, such as, a compression cycle of a vapor-compression circuit; and the working fluid outlet 1120 is configured to direct the conditioned working fluid, e.g., working fluid that has at least been de-superheated, condensed, and subcooled, out of the shell.

[0130] A plurality of heat-exchanging channels 1140 extend in the shell between the first end plate 1114 and the second end plate 1116 in a longitudinal direction defined by a length L of the shell to pass a working fluid for heat exchange with the process fluid inside the volume of the shell. One or more of the open ends of the heat-exchanging channels are attached to a tube sheet to form an inlet region and an outlet region on the tube sheet.

[0131] The heat-exchanging channels 1140 are tube-like channels that are in a heat exchanging stacked plate configuration, such that the heat-exchanging channels 1140 are formed in plates 1142 that are formed from a plurality of continuous plates that are stacked to form each of the heat-exchanging channels 1140 forming two or more passes, and in some embodiments, three, four, or more passes, within the shell 1112, e.g., along outer surfaces of the channels. In this embodiment, some of the heat-exchanging channels 1140 are formed from a bent plate to form the different branches, e.g., channels in the same pass, in which a plurality of plates 1142 are provided for forming the entirety of the two or more passes. Generally, each of the heat-exchanging channels 1140 are formed to start at the inlet region, run along or across the shell 1112 in the longitudinal direction defined by a length L, and then turned close to the second end of the shell 1112 forming at least one bending section or turn section. The channels then run across the shell 1112 in the longitudinal direction defined by the length L again, until the two or more passes are formed in which the other open ends of the heat-exchanging channels 1140 end at the outlet region, in which an additional at least one bending section or turn section is provided. As illustrated in FIG. 11, the heat-exchanging channels 1140 are formed to have eight passes, but such disclosure is not intended to be limiting, as a number of different passes can be used, as discussed above.

[0132] For example, in an embodiment, the heat-exchanging channels 1140 can be formed as stacked plates having continuous channels that are formed from one or more of the bent plates to include at least a third pass (Pass 01), a second pass (Pass 02), and a first pass (Pass 03) between the end plates of the heat exchanger 1110. The third pass (Pass 01) is configured for de-superheating the working fluid inside the tubes and boiling and superheating the process fluid, e.g., vaporizing water into steam and superheating the steam, in the volume of the shell 1112. The second pass (Pass 02) is configured for condensation of the working fluid inside the heat-exchanging channels 1140 and vaporizing / boiling of the process fluid in the volume of the shell 1112. The first pass (Pass 03) is configured for subcooling the working fluid in the heat-exchanging channels 1140 and preheating and / or nucleating the process fluid, e.g., water, in the volume of the shell 1112. In some embodiments, one or more of the passes can include additional pass(es). For example, in the illustrated embodiment, the passes can include two or more passes or include a single pass. As such, in the illustrated embodiment, the heat-exchanging channels 1140 are designed and / or provided to include eight passes through the three zones, e.g., Zone 1, Zone 2, Zone 3, which is not intended to be limiting in scope, but for understanding of the disclosure.

[0133] The shell 1112 further includes a process fluid inlet 1122 and process fluid outlet 1124. The process fluid inlet 1122 is configured to receive a process fluid, such as water, from a water storage tank or water supply line; and the process fluid outlet 1124 is configured to direct the conditioned process fluid, e.g., steam generated from water that has at least been vaporized and superheated, out of the shell 1112 to a steam distribution header or steam storage. Typically, the process fluid inlet 1122 is located closer to the bottom of the shell 1112 for at least partially flooding one or more of the channels in the volume of the shell 1112 to ensure proper heat exchange in the respective zones, as discussed herein, and the process fluid outlet 1124 is located closer to the top of the shell 1112 to allow the vaporized process fluid to exit the volume of the shell 1112 at a top of the shell 1112. In some embodiments, the process fluid inlet 1122 can include a diffuser or distributor for distributing the process fluid in the volume of the shell 1112.

[0134] As such, as illustrated in FIG. 11, the heat exchanger 1110 is configured to have at least three heat exchange zones or regions including, but not limited to, a first zone, Zone 1; a second zone, Zone 2; and a third zone, Zone 3. The first zone, Zone 1, is a water pre-heating / refrigerant subcooling region that includes the first pass (Pass 03) that is designed or otherwise configured to subcool the refrigerant with minimal pressure drop of refrigerant and to bring the water temperature to saturated boiling temperature. The second zone, Zone 2, is a water boiling / refrigerant condensation region that includes the second pass (Pass 02) that is designed or otherwise configured to maximize the steam generation rate. The third zone, Zone 3, is a steam superheater / refrigerant desuperheater region that includes the third pass (Pass 01) that is designed to de-superheat the refrigerant and to boil the water and / or superheat the steam. The working fluid is provided in the zones that are countercurrent to the supply of the process fluid. For example, in an embodiment, the heat exchanger is configured as a flooded heat exchanger in which a predetermined amount of tubes are covered by the water, e.g., between Zone 2 and Zone 3, such that the zones are provided sequentially to heat the process fluid from the first heat exchange zone (Zone 1) to the second heat exchange zone (Zone 2) to the third heat exchange zone (Zone 3). Thus, each zone or region of the heat exchanger 1110 is configured and / or designed such that the heat exchanger 1110 and heat-exchanging channels 1140 are designed or otherwise provided considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water. It is understood that in such design, the channel diameters of the heat-exchanging channels 1140 can be different between the different zones. In some embodiments, the channels can also be provided as a tapered design with narrowing diameter through one or more of the passes.

[0135] FIGS. 12A and 12B illustrate a plate design for heat-exchanging channels 1240 that can be used with any of the steam generation units, as discussed above. It is understood that different configurations can be used to provide the efficient heat transfer coefficient for vaporizing the process fluid, e.g., water, based on the heat available from the working fluid, e.g., refrigerant. In this embodiment, the plates are provided as pillow-plates, e.g., having a wavy, “pillow-shaped” surface formed by an inflation process or dimpling process. The pillow-plates can have single-embossed or double-embossed designs and can be provided as rectangular plates, circular plates, or spiral-shaped plates. In another embodiment, the plates may be dimple-plates, e.g., having panels attached to each other at dimples formed in the panels. The dimple-plates can have dimples formed in one or both of the panels. It is appreciated that the unique dimpled structure of pillow plates can be configured to create turbulence in the fluid flow, which can significantly enhance the heat transfer coefficient compared to smooth plates, e.g., the design is configured to handle high heat flux to enhance the overall heat transfer coefficient.

[0136] The steam generation unit 1210 is configured to receive a working fluid, such as a refrigerant, from a vapor-compression circuit of a HVACR system, such as, the HVACR systems 100 or 200 as shown in FIGS. 1 and 2, and to generate a vapor, such as steam, from a process fluid. The steam generation unit 1210 includes a shell 1212 having a first end plate 1214 and a second end plate 1216, in which the shell 1212, the first end plate 1214, and the second end plate 1216 define a volume for receiving a process fluid, such as water. The shell includes a working fluid inlet 1218 and a working fluid outlet 1220. The working fluid inlet 1218 is configured to receive a working fluid, such as refrigerant, from a HVACR system, such as, a compression cycle of a vapor-compression circuit; and the working fluid outlet 1220 is configured to direct the conditioned working fluid, e.g., working fluid that has at least been de-superheated, condensed, and subcooled, out of the shell. While the steam generation unit 1210 and plates 1242 are illustrated in a horizontal arrangement, such disclosure is not intended to be limiting. Rather, it is understood that the plates 1242 can be provided in alternate arrangements, such as, in a vertical arrangement.

[0137] Plates 1242 include the plurality of heat-exchanging channels 1240 having a wave-design that are stacked in the shell 1212 longitudinally, such that the channels 1240 extend both in a vertical direction defined by a height and horizontal direction defined by a length of the shell to pass a working fluid for heat exchange with the process fluid inside the volume of the shell. That is, it is understood that the plates 1242 are stacked along a width of the shell 1212 to form a compact design. One or more of the open ends of the heat-exchanging channels are attached to the working fluid inlet 1218 and the working fluid outlet 1220.

[0138] As illustrated in FIG. 12B, the heat-exchanging channels 1240 are formed to have one pass and run vertically along the length of the shell e.g., in a falling-film arrangement, and / or longitudinally across the shell. The working fluid can be directed to the working fluid inlet 1218 which is configured to supply the working fluid to the open ends of the channels 1240, e.g., via a header which can be tapered or a flow forced across the openings of the channels 1240, or submerged below water line 1250. In some embodiments, partitions (for example, as discussed below) can be provided to assist the falling arrangement of the working fluid. For example, in some embodiments, the partitions can be provided vertically along the plates 1242 such that the working fluid falls vertically along the plates 1242. In some embodiments, the partitions can be provided such that the working fluid falls vertically and at least partially horizontally along the plates 1242 to direct the working fluid along the plates 1242.

[0139] For example, in an embodiment, the heat-exchanging channels 1240 can be formed as stacked plates 1242 having continuous channels that are formed from one or more of the pillow-plates to include at least a fourth pass, a third pass, a second pass, and a first pass. The first pass is configured for de-superheating the working fluid inside the tubes and boiling and superheating the process fluid, e.g., vaporizing water into steam and superheating the steam, in the volume of the shell. The second and / or third pass is configured for condensation of the working fluid inside the heat-exchanging channels 1240 and vaporizing / boiling of the process fluid in the volume of the shell. The fourth pass is configured for subcooling the working fluid in the heat-exchanging channels 1240 and preheating and / or nucleating the process fluid, e.g., water, in the volume of the shell.

[0140] The shell 1212 further includes a process fluid inlet 1222 and process fluid outlet 1224. The process fluid inlet is configured to receive a process fluid, such as water, from a water storage tank or water supply line; and the process fluid outlet 1224 is configured to direct the conditioned process fluid, e.g., steam generated from water that has at least been vaporized and superheated, out of the shell 1212 to a steam distribution header or steam storage. Typically, the process fluid inlet is located closer to the bottom of the shell 1212 for at least partially flooding one or more of the channels in the volume of the shell 1212 to ensure proper heat exchange in the respective zones, as discussed herein, and the process fluid outlet 1224 is located closer to the top of the shell 1212 to allow the vaporized process fluid to exit the volume of the shell 1212 at a top of the shell 1212. In some embodiments, the process fluid inlet can include a diffuser or distributor for distributing the process fluid in the volume of the shell 1212.

[0141] As such, the heat exchanger having the heat-exchanging channels 1240 is configured to have at least four heat exchange zones or regions including, but not limited to, a first zone, Zone 1; a second zone, Zone 2; a third zone, Zone 3; and a fourth zone, Zone 4. The fourth zone, Zone 4, is a water pre-heating / refrigerant subcooling region that includes the fourth pass that is designed or otherwise configured to subcool the refrigerant with minimal pressure drop of refrigerant and to bring the water temperature to saturated boiling temperature. The second and / or third zone, Zone 2 and / or 3, is a water boiling / refrigerant condensation region that includes the second pass and / or the third pass that is designed or otherwise configured to maximize the steam generation rate. The first zone, Zone 1, is a steam superheater / refrigerant desuperheater region that includes the first pass that is designed to de-superheat the refrigerant and to boil the water and / or superheat the steam. It is also appreciated that the steam can be further superheated above the water line 1250, e.g., by the first pass. The working fluid is provided in the zones that are countercurrent to the supply of the process fluid. For example, in an embodiment, the heat exchanger is configured as a flooded heat exchanger in which a predetermined amount of channels are covered by the water, e.g., at the water line 1250 that is at least partially above Zone 1, such that the zones are provided sequentially to heat the process fluid from the fourth heat exchange zone (Zone 4) to the third heat exchange zone (Zone 3) to the second heat exchange zone (Zone 2) and to the first heat exchange zone (Zone 1). Thus, each zone or region of the heat exchanger is configured and / or designed such that the heat exchanger and heat-exchanging channels 1240 are designed or otherwise provided considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water.

[0142] FIGS. 13A and 13B illustrate a plate design for heat-exchanging channels 1340 that can be used with any of the steam generation units, as discussed above. It is understood that different configurations can be used to provide the efficient heat transfer coefficient for vaporizing the process fluid, e.g., water, based on the heat available from the working fluid, e.g., refrigerant. In this embodiment, the plates are provided as pillow-plates, e.g., having a “pillow-shaped” surface formed by an inflation process or dimpling process. The pillow-plates can have single-embossed or double-embossed designs and can be provided as rectangular plates, circular plates, or spiral-shaped plates. In another embodiment, the plates may be dimple-plates, e.g., having panels attached to each other at dimples formed in the panels. As such, such a configuration can allow for a compact design.

[0143] The steam generation unit 1310 is configured to receive a working fluid, such as a refrigerant, from a vapor-compression circuit of a HVACR system, such as, the HVACR systems 100 or 200 as shown in FIGS. 1 and 2, and to generate a vapor, such as steam, from a process fluid. The steam generation unit 1310 includes a shell 1312 having a first end plate 1314 and a second end plate 1316, in which the shell 1312, the first end plate 1314, and the second end plate 1316 define a volume for receiving a process fluid, such as water. The shell includes a working fluid inlet 1318 and a working fluid outlet 1320. The working fluid inlet 1318 is configured to receive a working fluid, such as refrigerant, from a HVACR system, such as, a compression cycle of a vapor-compression circuit; and the working fluid outlet 1320 is configured to direct the conditioned working fluid, e.g., working fluid that has at least been de-superheated, condensed, and subcooled, out of the shell.

[0144] Plates 1342 include the plurality of heat-exchanging channels 1340 having a wave-design are provided in a stacked arrangement laterally in the shell 1312 such that the channels 1340 extend along a width of the shell 1312 and in a vertical direction as partitioned into a plurality of zones, as further discussed below, to pass a working fluid for heat exchange with the process fluid inside the volume of the shell 1312. That is, it is understood that the plates 1342 are stacked along the length of the shell 1312 to form a compact design. One or more of the open ends of the heat-exchanging channels are attached to the working fluid inlet 1318 and the working fluid outlet 1220.

[0145] As illustrated in FIG. 13B, the heat-exchanging channels 1340 are formed to have two or more passes, and in some embodiments, three, four, or more passes, within the shell 1312. In some embodiments, the channels 1340 can be formed as multiple channel sections that are separated by partitions 1346 to form the different passes, in which a plurality of channels 1340 are provided for forming the entirety of the two or more passes, e.g., channels along the same horizontal plane. In some embodiments, the partitions 1346 can be an additional element provided in the plate 1342 or formed, e.g., dimpling, stamping, or bending, in the plate 1342 to form the separate passes. Generally, each of the channel configurations 1340 starts at the inlet region from the working fluid inlet 1318 runs along a width of the shell 1312, and then falls vertically to the next pass and then run across the shell 512 in the width direction again, until the two or more passes are formed in which the other open ends of the channel configurations 1340 end at the outlet region at the working fluid outlet 1320. As illustrated in FIGS. 13A and 13B, the channel configurations 1340 are formed to have four passes.

[0146] For example, in an embodiment, the heat-exchanging channels 1340 can be formed as stacked plates 1342 having continuous channels that are separated into the four passes that are formed from one or more of the pillow-plates to include at least a fourth pass, a third pass, a second pass, and a first pass. The first pass is configured for de-superheating the working fluid inside the tubes and boiling and superheating the process fluid, e.g., vaporizing water into steam and superheating the steam, in the volume of the shell. The second and / or third pass is configured for condensation of the working fluid inside the heat-exchanging channels 1340 and vaporizing / boiling of the process fluid in the volume of the shell. The fourth pass is configured for subcooling the working fluid in the heat-exchanging channels 1340 and preheating and / or nucleating the process fluid, e.g., water, in the volume of the shell.

[0147] The shell 1312 further includes a process fluid inlet (not shown) and process fluid outlet 1324. The process fluid inlet is configured to receive a process fluid, such as water, from a water storage tank or water supply line; and the process fluid outlet 1324 is configured to direct the conditioned process fluid, e.g., steam generated from water that has at least been vaporized and superheated, out of the shell 1312 to a steam distribution header or steam storage. Typically, the process fluid inlet is located closer to the bottom of the shell 1312 for at least partially flooding one or more of the channels in the volume of the shell 1312 to ensure proper heat exchange in the respective zones, as discussed herein, and the process fluid outlet 1324 is located closer to the top of the shell 1312 to allow the vaporized process fluid to exit the volume of the shell 1312 at a top of the shell 1312. In some embodiments, the process fluid inlet can include a diffuser or distributor for distributing the process fluid in the volume of the shell 1312.

[0148] As such, the heat exchanger having the heat-exchanging channels 1340 is configured to have at least four heat exchange zones or regions including, but not limited to, a first zone, Zone 1; a second zone, Zone 2; a third zone, Zone 3; and a fourth zone, Zone 4. The fourth zone, Zone 4, is a water pre-heating / refrigerant subcooling region that includes the fourth pass that is designed or otherwise configured to subcool the refrigerant with minimal pressure drop of refrigerant and to bring the water temperature to saturated boiling temperature. The second and / or third zone, Zone 2 and / or 3, is a water boiling / refrigerant condensation region that includes the second pass and / or the third pass that is designed or otherwise configured to maximize the steam generation rate. The first zone, Zone 1, is a steam superheater / refrigerant desuperheater region that includes the first pass that is designed to de-superheat the refrigerant and to boil the water and / or superheat the steam. The working fluid is provided in the zones that are countercurrent to the supply of the process fluid. For example, in an embodiment, the heat exchanger is configured as a flooded heat exchanger in which a predetermined amount of channels are covered by the water, e.g., at the water line 1350 that is above Zone 1, such that the zones are provided sequentially to heat the process fluid from the fourth heat exchange zone (Zone 4) to the third heat exchange zone (Zone 3) to the second heat exchange zone (Zone 2) and to the first heat exchange zone (Zone 1). Thus, each zone or region of the heat exchanger is configured and / or designed such that the heat exchanger and heat-exchanging channels 1340 are designed or otherwise provided considering the heat transfer phase of the process fluid, e.g., single phase or two-phase region for boiling and superheating water.

[0149] Aspects: Any of Aspects 1 – 9 may be combined with any of Aspects 10 – 20 and / or Aspects 21-36.

[0150] Aspect 1. A steam generation unit for a heating, ventilation, air conditioning, and refrigeration ( HVACR) system comprising: a mixed-phase heat exchanger including: a shell and end plates for receiving a process fluid in a volume defined by the shell and the end plates, the shell including a process fluid inlet at a bottom of the shell for receiving the process fluid and a process fluid outlet at a top of the shell for discharging the process fluid, and channels disposed inside the shell that extend between the end plates to pass a working fluid for heat exchange with the process fluid in the volume of the shell, wherein the shell and the channels are configured to define at least a first heat exchange zone comprising a first pass of the channels for preheating the process fluid in the volume of the shell, a second heat exchange zone comprising a second pass of the channels for boiling the process fluid in the volume of the shell, and a third heat exchange zone comprising a third pass of the channels for superheating the process fluid in the volume of the shell, and wherein the steam generation unit is configured to heat the process fluid sequentially from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone, and wherein the third pass of the channels includes a working fluid inlet that is configured to receive the working fluid and the first pass of the channels includes a working fluid outlet that is configured to return the working fluid.

[0151] Aspect 2. The steam generation unit of Aspect 1, wherein the third pass of the channels are for de-superheating the working fluid, the second pass of the channels are for condensing the working fluid, and the first pass of the channels are for subcooling the working fluid, and the steam generation unit is configured to cool the working fluid sequentially from the third heat exchange zone to the second heat exchange zone to the first heat exchange zone.

[0152] Aspect 3. The steam generation unit of any one of Aspects 1 – 2, further comprising: a liquid heat exchanger; and a gas heat exchanger, wherein the first process fluid is sequentially heated by the liquid heat exchanger, the mixed-phase heat exchanger, and the gas heat exchanger in that order, and the working fluid is sequentially cooled by the gas heat exchanger, the mixed-phase heat exchanger, and the liquid heat exchanger in that order.

[0153] Aspect 4. The steam generation unit of any one of Aspects 1 –3, wherein the channels in the first pass of the channels, the channels of the second pass of the channels, and the channels of the third pass of the channels are separate channels from each other.

[0154] Aspect 5. The steam generation unit of any one of Aspects 1 – 4, wherein the end plates includes distribution chambers, each of the channels extends from a first respective one of the distribution chambers to a second respective one of the distribution chambers.

[0155] Aspect 6. The steam generation unit of Aspect 5, wherein the distribution chambers include: an inlet distribution chamber configured to supply the working fluid to each of the channels in the first pass, a first intermediate distribution chamber configured to direct working fluid from the channels in the first pass and to each of the channels in the second pass, a second intermediate distribution chamber configured to direct the working fluid from the channels in the second pass and to each of the channels in the third pass, and an outlet distribution chamber configured to receive the working fluid from the channels in the third pass.

[0156] Aspect 7. The steam generation unit of any one of Aspects 1 – 6, wherein the heat exchanger includes tubes that extends from a first one of the end plates to a second one of the end plates, the channels each being formed by a respective tube in the tube bundle.

[0157] Aspect 8. The steam generation unit of any one of Aspects 1 –7, further comprising: a process fluid return line fluidly connected to the shell of the mixed-phase heat exchanger; and a level controller configured to control a liquid level of the process fluid in the shell by controlling discharge of the working fluid through the process fluid return line.

[0158] Aspect 9. The steam generation unit of Aspect 8, wherein the level controller is configured to control the liquid level to be within the third heat exchange zone above at least one row of the channels of the third pass and below at least one row of the channels of the third pass.

[0159] Aspect 10. A heating, ventilation, air conditioning, and refrigeration (HVACR) system comprising: a refrigerant circuit including a compressor, a steam generation unit, an expander, and an evaporator fluidly connected, the refrigerant circuit including a working fluid, the steam generation unit configured to heat the first process fluid using the working fluid compressed by the compressor, the refrigerant circuit including a refrigerant, wherein a steam generation unit includes: a mixed-phase heat exchanger including: a shell and end plates for receiving a process fluid in a volume defined by the shell and the end plates, the shell including a process fluid inlet at a bottom of the shell for receiving the process fluid and a process fluid outlet at a top of the shell for discharging the process fluid, and channels disposed inside the shell that extend between the end plates to pass a working fluid for heat exchange with the process fluid in the volume of the shell, wherein the shell and the channels are configured to define at least a first heat exchange zone comprising a first pass of the channels for preheating the process fluid in the volume of the shell, a second heat exchange zone comprising a second pass of the channels for boiling the process fluid in the volume of the shell, and a third heat exchange zone comprising a third pass of the channels for superheating the process fluid in the volume of the shell, and wherein the steam generation unit is configured to heat the process fluid sequentially from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone, and wherein the third pass of the channels includes a working fluid inlet that is configured to receive the working fluid and the first pass of the channels includes a working fluid outlet that is configured to return the working fluid.

[0160] Aspect 11. The HVACR system of Aspect 10, wherein the third pass of the channels are for de-superheating the working fluid, the second pass of the channels are for condensing the working fluid, and the first pass of the channels are for subcooling the working fluid, and the steam generation unit is configured to cool the working fluid sequentially from the third heat exchange zone to the second heat exchange zone to the first heat exchange zone.

[0161] Aspect 12. The HVACR system of any one of Aspects 10 – 11, wherein the channels in the first pass of the channels, the channels of the second pass of the channels, and the channels of the third pass of the channels are separate channels from each other.

[0162] Aspect 13. The HVACR system of any one of Aspects 10 – 12, wherein the steam generation unit includes a liquid heat exchanger and a gas heat exchanger, the refrigerant circuit includes the liquid heat exchanger and the gas heat exchanger, and the first process fluid is sequentially heated by the liquid heat exchanger, the mixed-phase heat exchanger, and the gas heat exchanger in that order, and the working fluid is sequentially cooled by the gas heat exchanger, the mixed-phase heat exchanger, and the liquid heat exchanger in that order.

[0163] Aspect 14. The HVACR system of Aspect 13, wherein the gas heat exchanger is configured to reduce a superheat of the working fluid and increase a superheat of the first process fluid, and the liquid heat exchanger is configured to increase a subcooling of the working fluid and decrease subcooling of the first process fluid,

[0164] Aspect 15. The HVACR system of any one of Aspects 10 – 14, wherein the end plates includes distribution chambers, each of the channels extends from a first respective one of the distribution chambers to a second respective one of the distribution chambers.

[0165] Aspect 16. The HVACR system of Aspect 15, wherein the distribution chambers include: an inlet distribution chamber configured to supply the working fluid to each of the channels in the first pass, a first intermediate distribution chamber configured to direct working fluid from the channels in the first pass and to each of the channels in the second pass, a second intermediate distribution chamber configured to direct the working fluid from the channels in the second pass and to each of the channels in the third pass, and an outlet distribution chamber configured to receive the working fluid from the channels in the third pass.

[0166] Aspect 17. The HVACR system of any one of Aspects 10 – 16, wherein the heat exchanger includes tubes that extends from a first one of the end plates to a second one of the end plates, the channels each being formed by a respective tube in the tube bundle.

[0167] Aspect 18. The HVACR system of any one of Aspects 10 – 17, further comprising: a process fluid return line fluidly connected to the shell of the mixed-phase heat exchanger, the first process fluid discharged through the process fluid return line configured to be mixed with an inlet stream of the process fluid flowing to the shell; and a level controller configured to control a liquid level of the first process fluid in the shell by controlling discharge of the first process fluid through the process fluid return line.

[0168] Aspect 19. The HVACR system of Aspect 18, wherein the level controller is configured to control the liquid level to be within the third heat exchange zone above at least one row of the channels of the third pass and below at least one row of the channels of the third pass.

[0169] Aspect 20. The HVACR system of any one of Aspects 10 – 19, wherein the compressor is for compressing a working fluid, the steam generation unit is for cooling the working fluid with the first process fluid, an expander is for expanding the working fluid cooled by the steam generation unit, and an evaporator is for cooling the working fluid expanded by the expander using a second process fluid.

[0170] Aspect 21. A steam generation unit comprising: a heat exchanger having a shell and end plates for receiving a process fluid in a volume defined by the shell and the end plates; and a plurality of channels disposed inside the shell that extend between the end plates of the heat exchanger to pass a working fluid for heat exchange with the process fluid in the volume of the shell, wherein the shell includes a process fluid inlet at a bottom of the shell for receiving the process fluid and a process fluid outlet at a top of the shell for exiting the process fluid, wherein the shell and the plurality of channels are configured to define at least a first heat exchange zone comprising a first pass of the plurality of channels for preheating the process fluid in the volume of the shell, a second heat exchange zone comprising a second pass of the plurality of channels for boiling the process fluid in the volume of the shell, and a third heat exchange zone comprising a third pass of the plurality of channels for superheating the process fluid in the volume of the shell, and, wherein the steam generation unit is configured to heat the process fluid sequentially from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone, and wherein the third pass includes a working fluid inlet that is configured to receive the working fluid and the first pass includes a working fluid outlet that is configured to return the working fluid.

[0171] Aspect 22. The steam generation unit of Aspects 1 or 21, wherein the plurality of channels includes a tube bundle that is continuously formed from the working fluid inlet to the working fluid outlet, wherein the tube bundle includes at least two bent sections.

[0172] Aspect 23. The steam generation unit of any of Aspects 1, 21-22, wherein the second heat exchange zone includes at least two passes for boiling the process fluid.

[0173] Aspect 24. The steam generation unit of any of Aspects 22-23, wherein at least the first pass and the third pass include fins for transferring heat from the working fluid to the process fluid.

[0174] Aspect 25. The steam generation unit of any of Aspects 22-24, wherein the tube bundle includes zig-zag tubes for enhancing turbulent flow inside tubes of the tube bundle.

[0175] Aspect 26. The steam generation unit of any of Aspects 22-25, wherein the tube bundle includes a continuous fin array along tubes of the tube bundle.

[0176] Aspect 27. The steam generation unit of any of Aspects 22-26, wherein the working fluid inlet and the working fluid outlet are on a same end of the shell.

[0177] Aspect 28. The steam generation unit of any of Aspects 1, 21-27, wherein the plurality of channels is formed by at least one heat exchanging plate.

[0178] Aspect 29. The steam generation unit of Aspect 28, wherein the plurality of channels includes multiple branches for passing the working fluid through the first heat exchange zone, the second heat exchange zone, and the heat exchange third zone.

[0179] Aspect 30. The steam generation unit of any of Aspects 28-29, wherein the working fluid inlet includes a distribution header provided through at least one of the end plates of the shell.

[0180] Aspect 31. The steam generation unit of any of Aspects 28-29, wherein the working fluid inlet includes a distribution header provided between at least one of the end plates of the shell and the plurality of channels.

[0181] Aspect 32. The steam generation unit of Aspect 29, wherein the at least one heat exchanging plate is continuous plate that is bent to correspond to the multiple branches.

[0182] Aspect 33. The steam generation unit of any of Aspects 28-32, wherein the at least one heat exchanging plates includes at least one vertical section between the first heat exchange zone and the third heat exchange zone.

[0183] Aspect 34. The steam generation unit of any of Aspects 28-33, wherein working fluid inlet and the working fluid outlet are on a same end of the shell.

[0184] Aspect 35. The steam generation unit of any of Aspects 1, 21-34, wherein the process fluid inlet includes a diffuser for distribution of the process fluid inside the volume of the shell.

[0185] Aspect 36. The steam generation unit of any of Aspects 1, 21-35, wherein the shell further includes a process fluid level sensor for maintaining a process fluid level in the heat exchanger between the second zone and the third zone.

[0186] The terminology used herein is intended to describe particular embodiments and is not intended to be limiting. The terms “a,”“an,” and “the” include the plural forms as well, unless clearly indicated otherwise. The terms “comprises” and / or “comprising,” when used in this Specification, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components. In an embodiment, “connected” and “connecting” as described herein can refer to being “directly connected” and “directly connecting”.

[0187] With regard to the foregoing description, it is to be understood that changes may be made in detail, without departing from the scope of the present invention. It is intended that the specification and depicted embodiments are to be considered exemplary only, with a true scope and spirit of the invention being indicated by the broad meaning of the claims.

Claims

1. A steam generation unit for a heating, ventilation, air conditioning, and refrigeration ( HVACR) system comprising:a mixed-phase heat exchanger including:a shell and end plates for receiving a process fluid in a volume defined by the shell and the end plates, the shell including a process fluid inlet at a bottom of the shell for receiving the process fluid and a process fluid outlet at a top of the shell for discharging the process fluid, andchannels disposed inside the shell that extend between the end plates to pass a working fluid for heat exchange with the process fluid in the volume of the shell,wherein the shell and the channels are configured to define at least a first heat exchange zone comprising a first pass of the channels for preheating the process fluid in the volume of the shell, a second heat exchange zone comprising a second pass of the channels for boiling the process fluid in the volume of the shell, and a third heat exchange zone comprising a third pass of the channels for superheating the process fluid in the volume of the shell, andwherein the steam generation unit is configured to heat the process fluid sequentially from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone, andwherein the third pass of the channels includes a working fluid inlet that is configured to receive the working fluid and the first pass of the channels includes a working fluid outlet that is configured to return the working fluid.

2. The steam generation unit of claim 1, whereinthe third pass of the channels are for de-superheating the working fluid, the second pass of the channels are for condensing the working fluid, and the first pass of the channels are for subcooling the working fluid, andthe steam generation unit is configured to cool the working fluid sequentially from the third heat exchange zone to the second heat exchange zone to the first heat exchange zone.

3. The steam generation unit of claim 1, further comprising:a liquid heat exchanger; anda gas heat exchanger,wherein the first process fluid is sequentially heated by the liquid heat exchanger, the mixed-phase heat exchanger, and the gas heat exchanger in that order, and the working fluid is sequentially cooled by the gas heat exchanger, the mixed-phase heat exchanger, and the liquid heat exchanger in that order.

4. The steam generation unit of claim 1, whereinthe channels in the first pass of the channels, the channels of the second pass of the channels, and the channels of the third pass of the channels are separate channels from each other.

5. The steam generation unit of claim 1, wherein the end plates includes distribution chambers, each of the channels extends from a first respective one of the distribution chambers to a second respective one of the distribution chambers.

6. The steam generation unit of claim 5, wherein the distribution chambers include:an inlet distribution chamber configured to supply the working fluid to each of the channels in the first pass,a first intermediate distribution chamber configured to direct working fluid from the channels in the first pass and to each of the channels in the second pass,a second intermediate distribution chamber configured to direct the working fluid from the channels in the second pass and to each of the channels in the third pass, andan outlet distribution chamber configured to receive the working fluid from the channels in the third pass.

7. The steam generation unit of claim 1, wherein the heat exchanger includes tubes that extends from a first one of the end plates to a second one of the end plates, the channels each being formed by a respective tube in the tube bundle.

8. The steam generation unit of claim 1, further comprising:a process fluid return line fluidly connected to the shell of the mixed-phase heat exchanger; anda level controller configured to control a liquid level of the process fluid in the shell by controlling discharge of the working fluid through the process fluid return line.

9. The steam generation unit of claim 8, wherein the level controller is configured to control the liquid level to be within the third heat exchange zone above at least one row of the channels of the third pass and below at least one row of the channels of the third pass.

10. A heating, ventilation, air conditioning, and refrigeration (HVACR) system comprising:a refrigerant circuit including a compressor, a steam generation unit, an expander, and an evaporator fluidly connected, the refrigerant circuit including a working fluid, the steam generation unit configured to heat the first process fluid using the working fluid compressed by the compressor, the refrigerant circuit including a refrigerant, whereina steam generation unit includes:a mixed-phase heat exchanger including:a shell and end plates for receiving a process fluid in a volume defined by the shell and the end plates, the shell including a process fluid inlet at a bottom of the shell for receiving the process fluid and a process fluid outlet at a top of the shell for discharging the process fluid, andchannels disposed inside the shell that extend between the end plates to pass a working fluid for heat exchange with the process fluid in the volume of the shell,wherein the shell and the channels are configured to define at least a first heat exchange zone comprising a first pass of the channels for preheating the process fluid in the volume of the shell, a second heat exchange zone comprising a second pass of the channels for boiling the process fluid in the volume of the shell, and a third heat exchange zone comprising a third pass of the channels for superheating the process fluid in the volume of the shell, andwherein the steam generation unit is configured to heat the process fluid sequentially from the first heat exchange zone to the second heat exchange zone to the third heat exchange zone, andwherein the third pass of the channels includes a working fluid inlet that is configured to receive the working fluid and the first pass of the channels includes a working fluid outlet that is configured to return the working fluid.

11. The HVACR system of claim 10, whereinthe third pass of the channels are for de-superheating the working fluid, the second pass of the channels are for condensing the working fluid, and the first pass of the channels are for subcooling the working fluid, andthe steam generation unit is configured to cool the working fluid sequentially from the third heat exchange zone to the second heat exchange zone to the first heat exchange zone.

12. The HVACR system of claim 10, whereinthe channels in the first pass of the channels, the channels of the second pass of the channels, and the channels of the third pass of the channels are separate channels from each other.

13. The HVACR system of claim 10, whereinthe steam generation unit includes a liquid heat exchanger and a gas heat exchanger, the refrigerant circuit includes the liquid heat exchanger and the gas heat exchanger, andthe first process fluid is sequentially heated by the liquid heat exchanger, the mixed-phase heat exchanger, and the gas heat exchanger in that order, and the working fluid is sequentially cooled by the gas heat exchanger, the mixed-phase heat exchanger, and the liquid heat exchanger in that order.

14. The HVACR system of claim 13, whereinthe gas heat exchanger is configured to reduce a superheat of the working fluid and increase a superheat of the first process fluid, andthe liquid heat exchanger is configured to increase a subcooling of the working fluid and decrease subcooling of the first process fluid.

15. The HVACR system of claim 10, wherein the end plates includes distribution chambers, each of the channels extends from a first respective one of the distribution chambers to a second respective one of the distribution chambers.

16. The HVACR system of claim 15, wherein the distribution chambers include:an inlet distribution chamber configured to supply the working fluid to each of the channels in the first pass,a first intermediate distribution chamber configured to direct working fluid from the channels in the first pass and to each of the channels in the second pass,a second intermediate distribution chamber configured to direct the working fluid from the channels in the second pass and to each of the channels in the third pass, andan outlet distribution chamber configured to receive the working fluid from the channels in the third pass.

17. The HVACR system of claim 10, wherein the heat exchanger includes tubes that extends from a first one of the end plates to a second one of the end plates, the channels each being formed by a respective tube in the tube bundle.

18. The HVACR system of claim 10, further comprising:a process fluid return line fluidly connected to the shell of the mixed-phase heat exchanger, the first process fluid discharged through the process fluid return line configured to be mixed with an inlet stream of the process fluid flowing to the shell; anda level controller configured to control a liquid level of the first process fluid in the shell by controlling discharge of the first process fluid through the process fluid return line.

19. The HVACR system of claim 18, wherein the level controller is configured to control the liquid level to be within the third heat exchange zone above at least one row of the channels of the third pass and below at least one row of the channels of the third pass.

20. The HVACR system of claim 10, whereinthe compressor is for compressing a working fluid,the steam generation unit is for cooling the working fluid with the first process fluid,an expander is for expanding the working fluid cooled by the steam generation unit, andan evaporator is for cooling the working fluid expanded by the expander using a second process fluid.

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