EP3627073A1 - Évaporateur noyé - Google Patents

Évaporateur noyé Download PDF

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Publication number
EP3627073A1
EP3627073A1 EP19189483.1A EP19189483A EP3627073A1 EP 3627073 A1 EP3627073 A1 EP 3627073A1 EP 19189483 A EP19189483 A EP 19189483A EP 3627073 A1 EP3627073 A1 EP 3627073A1
Authority
EP
European Patent Office
Prior art keywords
refrigerant fluid
evaporator
outlet
condenser
shell
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP19189483.1A
Other languages
German (de)
English (en)
Inventor
Giulio ONORATI
Luigi SORABELLA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daikin Applied Europa SpA
Original Assignee
Daikin Applied Europa SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daikin Applied Europa SpA filed Critical Daikin Applied Europa SpA
Publication of EP3627073A1 publication Critical patent/EP3627073A1/fr
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B25/00—Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D21/0017—Flooded core heat exchangers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D7/16—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2339/00—Details of evaporators; Details of condensers
    • F25B2339/02—Details of evaporators
    • F25B2339/024—Evaporators with refrigerant in a vessel in which is situated a heat exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2339/00—Details of evaporators; Details of condensers
    • F25B2339/02—Details of evaporators
    • F25B2339/024—Evaporators with refrigerant in a vessel in which is situated a heat exchanger
    • F25B2339/0242—Evaporators with refrigerant in a vessel in which is situated a heat exchanger having tubular elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/04—Refrigeration circuit bypassing means
    • F25B2400/0401—Refrigeration circuit bypassing means for the compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/04—Refrigeration circuit bypassing means
    • F25B2400/0409—Refrigeration circuit bypassing means for the evaporator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/04—Refrigeration circuit bypassing means
    • F25B2400/0411—Refrigeration circuit bypassing means for the expansion valve or capillary tube
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/13—Economisers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/31—Low ambient temperatures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
    • F28D2021/0068—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for refrigerant cycles
    • F28D2021/0071—Evaporators

Definitions

  • This invention relates to a flooded evaporator for a cooling system.
  • Cooling systems are commonly used to refrigerate a fluid such as air (in air conditioning systems or in refrigerators) or water (in industrial plants).
  • a fluid such as air (in air conditioning systems or in refrigerators) or water (in industrial plants).
  • free cooling systems In the cooling systems field, so called “free cooling systems" are known; such systems have a free-cooling mode and a cooling mode.
  • cooling systems are run in a cooling mode, wherein energy is expended by operating a compressor.
  • the free cooling systems may be run in the free-cooling mode, wherein the outside ambient air itself may be utilized to provide cooling to the working fluid without engaging the compressor.
  • a cooling system is known e.g. from patent document JPH0252959A .
  • Free cooling systems are disclosed in patent documents WO2008/079118A1 , WO2008/079138A1 , WO2008/079116A1 , WO2009/038552A1 .
  • These systems comprise a condenser, a compressor, an evaporator, an expansion device and a pump; in the cooling mode, the compressor works and the pump is bypassed, while in the free-cooling mode the pump works and the compressor is bypassed.
  • these systems have the drawback that they may be operated only in the cooling mode or, alternatively, in the free-cooling mode: if the outside temperature is not low enough to activate the free-cooling mode, the free-cooling concept may not be exploited, namely the outside ambient air may not be utilized to provide cooling.
  • the pump requires an energy expense and further limits the efficiency of the system in the free-cooling mode.
  • the evaporator of the free-cooling systems of the above cited documents have no specific requirements.
  • special evaporators called "flooded evaporators" are known, for example from patent document CN103925747A .
  • the flooded evaporator of such document includes: a housing, having an inlet on its bottom, for receiving liquid, and an outlet at its top, to release gas; a plurality of heat exchange tubes disposed in a housing; a distributor plate, arranged into the housing at its bottom, to avoid liquid discharge phenomenon; a retaining fluid plate arranged into the housing at its top, to prevent liquid drops to be released together with the gas (in fact, typically downstream of the evaporator a compressor is provided, and a presence of liquid drops in the gas results in cavitation inside the compressor, which is harmful for the compressors components).
  • the distributor plate and the retaining fluid plate produce pressure drops in the refrigeration circuit, which limit the performance of the refrigeration cycle.
  • Scope of the present invention is to provide an evaporator, a cooling system and a method for cooling which overcomes at least one of the aforementioned drawbacks.
  • a cooling system for cooling water More generally, it regards a cooling system for cooling a fluid (such as water or air).
  • a fluid such as water or air
  • the cooling system comprises a refrigeration circuit.
  • the refrigeration circuit is configured for circulating a refrigerant fluid.
  • the cooling system comprises an evaporator.
  • the evaporator is configured for providing a heat exchange between the refrigerant fluid (flowing in the refrigeration circuit) and the water to be cooled.
  • the cooling system comprises a compressor.
  • the compressor is configured for compressing the refrigerant fluid (flowing in the refrigeration circuit).
  • the compressor is positioned in the refrigeration circuit downstream of the evaporator.
  • the cooling system comprises a condenser.
  • the condenser is configured for providing a heat transfer from the refrigerant fluid (flowing in the refrigeration circuit) to ambient air.
  • the condenser preferably, is positioned in the refrigeration circuit downstream of the compressor.
  • the cooling system comprises an expansion device.
  • the expansion device is configured for expanding the refrigerant fluid.
  • the expansion device preferably, is positioned in the refrigeration circuit upstream of the evaporator.
  • the cooling system comprises an additional evaporator (further to the evaporator above disclosed).
  • the additional evaporator is configured to provide a heat exchange between the refrigerant fluid and water to be cooled. Specifically, in the additional evaporator, the heat is transferred from the water to the refrigerant fluid, resulting in an evaporation of the refrigerant fluid and a cooling of the water.
  • the additional evaporator is provided in the refrigeration circuit downstream of the condenser.
  • the additional evaporator includes an outlet for feeding the refrigerant fluid back to the condenser, so as to bypass the compressor. In fact, the outlet of the additional evaporator is connected to an inlet of the condenser. In this way, the compressor is bypassed.
  • the expansion device is bypassed.
  • the evaporator is bypassed.
  • two pathways for the refrigerant fluid are provided in the refrigeration circuit: in a first pathway (traditional cooling mode), the refrigerant fluid flows (successively) through the evaporator, the compressor, the condenser and the expansion device, from which it is fed again to the evaporator, in a second pathway (free-cooling mode), the refrigerant fluid flows through the additional evaporator, from which it is fed to the condenser, from which it is fed again to the additional evaporator and so on.
  • a first pathway traditional cooling mode
  • the refrigerant fluid flows (successively) through the evaporator, the compressor, the condenser and the expansion device, from which it is fed again to the evaporator
  • a second pathway free-cooling mode
  • the fluid may entirely be circulated through the second pathway (free-cooling mode), while if the ambient air has not a sufficiently low temperature, the fluid may be circulated partly through the first pathway and partly through the second pathway (in a hybrid mode, partly traditional cooling and partly free-cooling), or entirely through the first pathway (traditional cooling mode).
  • the additional evaporator includes a liquid zone. In an embodiment, the additional evaporator includes a vapor zone. The fluid coming from the condenser, being in a liquid phase, is received in the liquid zone. In fact, the additional evaporator includes an inlet which is provided at the liquid zone.
  • the refrigerant fluid is evaporated, absorbing heat from the water that is cooled.
  • the evaporating refrigerant fluid migrates from the liquid zone towards the vapor zone.
  • the vapor zone is provided above the liquid zone (along the vertical direction parallel to the weight force).
  • the refrigerant fluid is in a vapor phase (in particular, a saturated vapor phase).
  • the outlet of the additional evaporator is provided at the vapor zone.
  • the outlet of the additional evaporator is connected to the inlet of the condenser, for feeding the refrigerant fluid in the vapor phase back to the condenser. Therefore, the refrigerant fluid is condensed in the condenser, passing to the liquid phase, and is fed again to the liquid zone of the additional evaporator.
  • the additional evaporator has an additional outlet in the liquid zone.
  • the additional outlet is provided in a bottom of the additional evaporator.
  • the additional outlet is connected to the evaporator, for feeding to the evaporator the refrigerant fluid in the liquid phase.
  • the additional outlet of the additional evaporator is connected to the evaporator through the expansion device.
  • the refrigerant fluid in the liquid phase coming from the condenser is received in the additional evaporator, and exits the additional evaporator (in the liquid phase) through the additional outlet.
  • the additional evaporator may thus work as a liquid receiver.
  • the additional evaporator further includes an economizer outlet.
  • the economizer outlet is provided at the vapor zone.
  • the economizer outlet is connected to an economizer branch that is connected directly to the compressor.
  • the refrigerant fluid from the economizer outlet is fed to the compressor in the vapor phase, in order to cool it down.
  • the refrigerant fluid that is received into the liquid receiver namely the additional evaporator
  • the refrigerant fluid that is received into the liquid receiver may be in a saturated liquid phase, and may partially evaporate in the liquid receiver, producing a small amount of refrigerant fluid in the vapor phase (saturated gas).
  • This refrigerant fluid in the vapor phase (saturated gas) it extracted from the liquid receiver through the economizer outlet and is fed to the compressor.
  • the additional evaporator includes a shell.
  • the shell delimits an internal volume for containing the refrigerant fluid.
  • the inlet of the additional evaporator is open to the internal volume.
  • the outlet, the additional outlet and the economizer outlet are, also, in communication with the internal volume.
  • the liquid zone is provided at a lower portion of the shell and the vapor zone is provided ad an upper portion of the shell.
  • the upper portion of the shell is at a higher level (along the vertical direction, parallel to the weight force) with respect to the lower portion of the shell (liquid zone).
  • the additional evaporator includes a plurality of pipes.
  • the plurality of pipes may form a set of pipes.
  • the plurality of pipes passes through the internal volume.
  • the plurality of pipes may comprise a plurality of sets (that is, sub sets) of pipes.
  • the plurality of pipes includes a first sub set of pipes passing through the liquid zone and a second sub set of pipes passing through the vapor zone.
  • the set of pipes is configured for circulating water to be cooled.
  • the set of pipes is configured for cooling down the water flowing there through.
  • the additional evaporator is a flooded evaporator.
  • the system comprises a first controlled valve.
  • the first controlled valve is a (motorized) ball valve.
  • the first controlled valve is partialized.
  • the outlet of the additional evaporator is connected to an inlet of the condenser through the first controlled valve, to regulate the flow of refrigerant fluid passing there through.
  • the first controlled valve is operable in an open position (or configuration) and in a closed position (or configuration). In the following, the open configuration may be referred also as "first open configuration". In the (first) open configuration, the first controlled valve allows the refrigerant fluid to flow from the outlet of the flooded evaporator to the inlet of the condenser.
  • the first controlled valve is also operable in a second open configuration, which allows the refrigerant fluid to flow from the inlet of the condenser to the outlet of the flooded evaporator.
  • the cooling system comprises a second controlled valve.
  • the second controlled valve is a (motorized) ball valve.
  • the compressor has an outlet which is connected to the inlet of the condenser through the second controlled valve, to control (regulate) the flow of refrigerant fluid passing there through.
  • the second controlled valve is operable in an open position and in a closed position. In the closed position, the second controlled valve prevents a flow of refrigerant fluid back to the outlet of the compressor.
  • the cooling system comprises a control unit.
  • the control unit is programed for controlling the first controlled valve.
  • the control unit is programed for controlling the second controlled valve.
  • the expansion device is an expansion valve.
  • the expansion valve is operable in a closed configuration and in an open configuration.
  • the control unit is programed for controlling the expansion valve.
  • the control unit is programmed to operate the system in a free-cooling mode.
  • the free-cooling mode the first controlled valve is in the (first) open position and the second controlled valve is in the closed position (to avoid a migration of the refrigerant fluid to the compressor in the free-cooling mode).
  • the expansion valve is in the closed configuration, to prevent a flow of the refrigerant fluid in the liquid phase from the flooded evaporator towards the evaporator. Therefore, in the free-cooling mode, the refrigerant fluid (which has condensed in the condenser) is fed to the additional evaporator, where it evaporates, and then is fed again to the condenser.
  • the control unit is programmed to operate the system in a (traditional) cooling mode.
  • the first controlled valve In the (traditional) cooling mode the first controlled valve is in the closed position and the second controlled valve is in the open position.
  • the expansion valve in the (traditional) cooling mode the expansion valve is in the open configuration. Therefore, in the traditional cooling mode, the additional evaporator works as a mere liquid receiver: the refrigerant fluid in the liquid phase, from the condenser, is fed to the expansion valve (passing through the liquid receiver) and then, from the expansion valve is fed to the evaporator (to cool down the water flowing through the evaporator).
  • control unit is programmed to operate the system in a hybrid cooling mode.
  • the first controlled valve is in the open position and the second controlled valve is, also, in the open position.
  • the expansion valve is in the open configuration. Therefore, in the hybrid cooling mode, the refrigerant fluid in the liquid phase, from the condenser, is fed to the additional evaporator; in the additional evaporator, part of the refrigerant fluid evaporates and exiting from the outlet of the additional evaporator is fed back to the condenser, while the remaining part of the refrigerant fluid exiting from the additional outlet of the additional evaporator is fed to the expansion valve and then to the evaporator.
  • the partition of the refrigerant fluid between the outlet and the additional outlet is possible thanks to an appropriate dimensioning of the additional evaporator (specifically, of the internal volume and of the pipes) and appropriate partialisation of the first controlled valve and the second controlled valve.
  • control unit is configured to control the first and second controlled valve, to operate the system in the free-cooling mode, in the cooling mode and in the hybrid mode.
  • control unit is programmed to operate the system in a heat recovery mode (by opening both the first controlled valve and the second controlled valve).
  • the first controlled valve is in the second open configuration and the second controlled valve is in the open position.
  • the expansion valve is in the open configuration. Therefore, in the heat recovery mode, the refrigerant fluid in the vapor phase (coming from the compressor) is fed to the additional evaporator through the outlet, and the additional evaporator works as a condenser, thus the refrigerant fluid exits the additional evaporator in the liquid phase through the additional outlet.
  • the compressor in the heat recovery mode, is working.
  • the condenser may be bypassed or, more in general, may work in parallel to the heat exchanger.
  • This heat recovery mode is useful if there is a request for cooling a flow of water and, in the meantime, a request for warming another flow of water.
  • the system in the heat recovery mode, may work in (at least) two (sub)modes: (i) in a first mode, the heat exchanger works in parallel with the condenser; (ii) in a second mode, the condenser is bypassed and only the heat exchanger operates as condenser.
  • the additional evaporator is arranged, with respect to the condenser, at a lower level, in such a way as to allow the refrigerant fluid to move from the condenser to the additional evaporator by piezometric lift. Therefore, in the free-cooling mode, no pump is required to circulate the refrigerant fluid.
  • the refrigerant fluid in the liquid phase moves from the condenser to the additional (flooded) evaporator by effect of the piezometric lift, and the refrigerant fluid in the vapor phase naturally migrates from the additional (flooded) evaporator to the condenser (in fact, a gas naturally moves from a warmer zone to a cooler zone, and the evaporator is warmer than the condenser).
  • This circulation is possible because of the bypass branch (that connects the outlet of the additional evaporator directly to the inlet of the condenser), which, bypassing the compressor, the evaporator and the expansion device, minimizes the pressure drops.
  • the circulation is not achieved by means of the piezometric lift, but the system includes a liquid pump (arranged downstream of the condenser and upstream of the additional evaporator) to circulate the refrigerant fluid from the outlet of the condenser to the inlet of the additional evaporator.
  • a liquid pump arranged downstream of the condenser and upstream of the additional evaporator
  • the cooling system includes a water circuit for circulating the water to be cooled.
  • the water circuit passes through the evaporator.
  • the water circuit also passes through the additional evaporator.
  • water is circulated through the additional evaporator and, then, through the evaporator.
  • a water outlet of the additional evaporator, for releasing the water out of the additional evaporator is connected to a water inlet of the evaporator, for guiding said water to the evaporator.
  • water may be subjected to a first cooling step in the free-cooling mode (until a temperature compatible with the outside air temperature) and, then to a second cooling step in the (traditional) cooling mode (until the temperature desired, thanks to the energy supplied to the compressor).
  • the present description also relates to a method for cooling water.
  • the method comprises a step of circulating a refrigerant fluid in a refrigeration circuit.
  • the method comprises a step of evaporating the refrigerant fluid by transferring heat from water to be cooled to the refrigerant fluid, in an evaporator.
  • the method comprises a step of compressing the (evaporated) refrigerant fluid, through a compressor.
  • the method comprises a step of condensing the refrigerant fluid, through transferring heat from the refrigerant fluid to ambient air, in a condenser.
  • the condenser is provided downstream of the compressor.
  • the method comprises a step of expanding the (condensed) refrigerant fluid, through an expansion device.
  • the method comprises an additional step of evaporating the refrigerant fluid, by transferring heat from water to be cooled to the refrigerant fluid, through an additional evaporator.
  • the additional evaporator receives the refrigerant fluid from the condenser.
  • the method also includes a step of feeding the refrigerant fluid from the condenser (directly) to the additional evaporator.
  • the method comprises a step of feeding the refrigerant fluid coming out of the additional evaporator back to the condenser, so as to bypass the compressor.
  • the additional step of evaporating comprises generating a vapor phase of the refrigerant fluid (by transferring heat from the water to the refrigerant fluid, in the additional evaporator). In an embodiment, the additional step of evaporating comprises separating the vapor phase of the refrigerant fluid and a liquid phase of the refrigerant fluid. In an embodiment, in the feeding step the refrigerant fluid being in the vapor phase is fed from the additional evaporator to the condenser.
  • the method comprises a step of supplying the refrigerant fluid being in the additional evaporator in the liquid phase to the evaporator (through the expansion device).
  • the present description also regards a flooded evaporator.
  • the flooded evaporator comprises a shell, delimiting an internal volume, and a plurality (or set) of pipes passing through the internal volume.
  • the flooded evaporator includes an inlet and an outlet.
  • the inlet is provided at a lower portion of the shell, to receive a refrigerant fluid in a liquid phase.
  • the outlet is provided at an upper portion of the shell, to release the refrigerant fluid in a vapor phase.
  • the flooded evaporator is configured to provide a heat transfer from the fluid circulating in the plurality (or set) of pipes (preferably, water) to the refrigerant fluid flowing from the inlet to the outlet of the flooded evaporator.
  • the flooded evaporator comprises an additional outlet, provided at the lower portion of the shell, to release the refrigerant fluid in the liquid phase.
  • the object solution is aimed at providing a flooded evaporator and a cooling system having a simple layout, to be easily adaptable to various operating modes (free-cooling, traditional cooling and hybrid cooling).
  • the internal volume of the shell includes an upper volume delimited by the upper portion of the shell and by the plurality of pipes.
  • the outlet is open to the upper volume. Therefore, no plate (upper cap) for collecting drops is arranged between the plurality of pipes and the upper portion of the shell (such as in traditional flooded evaporators). This feature allows a reduction of the pressure drops, resulting in a higher performance.
  • the internal volume of the shell includes a lower volume delimited by the lower portion of the shell and by the plurality of pipes.
  • the inlet is open to the lower volume.
  • the additional outlet is open to the lower volume. Therefore, no distributor is provided between the lower portion of the shell and the plurality of pipes (such as in traditional flooded evaporators). This feature allows a reduction of the pressure drops.
  • the inlet has a size which is equal to a size of the additional outlet.
  • the flooded evaporator may efficiently work as a liquid receiver because the flow rate of the liquid that enters into the additional evaporator (through the inlet) may be equal to the flow rate of the liquid that exits the additional evaporator (through the additional outlet).
  • the flooded evaporator comprises an economizer outlet.
  • the economizer outlet is provided at the upper portion of the shell, to release the refrigerant fluid in the vapor phase.
  • the cooling system may include a single evaporator (which may be a flooded evaporator or a plate type evaporator or another type of evaporator), having an inlet for the liquid refrigerant fluid coming from the condenser at the liquid zone, and an outlet at the vapor zone.
  • a single evaporator which may be a flooded evaporator or a plate type evaporator or another type of evaporator
  • the fluid coming from the condenser passes through the expansion device, then through the evaporator, then through the compressor and finally is fed back to the condenser.
  • the fluid coming from the condenser is directly fed to the evaporator (preferably through a branch that bypasses the expansion device, in order to reduce the pressure drops), and then is directly fed back to the condenser (through a branch that bypasses the compressor).
  • the evaporator is located at a sufficiently lower level with respect to the condenser and the pressure drops are sufficiently low (thanks to the bypasses)
  • the fluid may circulate in the free-cooling mode without the provision of a pump, thanks to the piezometric lift.
  • the traditional cooling mode and the free-cooling mode are alternative.
  • the system may comprise the condenser and a single evaporator (which may be a flooded evaporator), without any compressor neither expansion valve.
  • the condenser is at a higher level with respect to the evaporator.
  • the system is only operable in the free-cooling mode (if the outside temperature is low enough).
  • this system has the benefit that it is glycol-free (since glycol is necessary to prevent icing of the water in the single heat exchanger).
  • the numeral 1 denotes a cooling system.
  • the cooling system 1 comprises a refrigeration circuit.
  • the cooling system 1 comprises an evaporator 2.
  • the evaporator 2 in a possible embodiment, is a plate-type heat exchanger.
  • the evaporator 2 has an inlet 21 for receiving refrigerant fluid (in the liquid phase).
  • the evaporator 2 has an outlet 22 for releasing the refrigerant fluid (in the vapor phase).
  • the evaporator 2 has a water inlet 25 for receiving water to be cooled.
  • the evaporator 2 has a water outlet 26 for releasing the water that has been cooled by releasing heat to the refrigerant fluid.
  • the cooling system 1 comprises a compressor 3.
  • the cooling system 1 comprises a couple of compressors 3.
  • the compressor 3 has an inlet 31 for receiving the refrigerant fluid coming from the outlet 22 of the evaporator.
  • the compressor 3 has an outlet 32 for releasing the compressed refrigerant fluid.
  • the cooling system 1 comprises a condenser 4.
  • the condenser 4 has an inlet 41 for receiving refrigerant fluid.
  • the inlet 41 of the condenser 4 receives the refrigerant fluid (being in the vapor phase) from the outlet 32 of the compressor 3.
  • the condenser 4 is configured to condense the refrigerant fluid by releasing heat to ambient air.
  • the condenser 4, in an embodiment, includes a plurality of air fans 43 configured for forcing ambient air.
  • the condenser 4 has an outlet 42 for releasing the refrigerant fluid in the liquid phase.
  • the cooling system 1 comprises a second controlled valve 72, between the outlet 32 of the compressor 3 and the inlet 41 of the condenser 4.
  • the second controlled valve 72 preferably, is an on/off valve (which has only two possible operating positions: closed and open). Operatively, the second controlled valve 72 is open when the compressor 3 is ON, and is closed when the compressor 3 is OFF.
  • the cooling system includes an additional evaporator 6.
  • the additional evaporator 6 is formed as a flooded evaporator 6.
  • the additional evaporator 6 has an inlet 61 for receiving the refrigerant fluid from the outlet 42 of the condenser 4 (in the liquid phase).
  • the additional evaporator has an outlet 62 for releasing the refrigerant fluid.
  • the additional evaporator 6 includes a shell 60.
  • the shell 60 delimits an internal volume.
  • the shell 60 includes an upper portion 601 and a lower portion 602.
  • the upper portion 601 is located above the lower portion 602, along a vertical direction V (parallel to the weight force).
  • the shell 60 has a cylindrical shape elongated along a longitudinal direction L.
  • the longitudinal direction L is perpendicular to the vertical direction V.
  • the upper portion 601 and the lower portion 602 has a semicircular cross section.
  • the inlet 61 is located at a lower portion 602 of the shell 60.
  • the outlet 62 is located at an upper portion 601 of the shell 60.
  • the additional evaporator 6 includes a plurality (or set) of pipes 67, that traverse the internal volume.
  • the pipes 67 are elongated along the longitudinal direction L.
  • the pipes 67 are configured to circulate warm water that has to be cooled.
  • the internal volume includes a lower volume which is delimited by the lower portion 602 of the shell 60 and by the plurality (or set) of pipes 67 (or by a part of the pipes 67).
  • the lower volume defines a liquid zone 68.
  • the inlet 61 is open to the lower volume, to fill the liquid zone 68 with liquid refrigerant fluid.
  • the internal volume includes an upper volume which is delimited by the upper portion 601 of the shell 60 and by the plurality (or set) of pipes 67 (or by a part of the pipes 67).
  • the upper volume defines a vapor zone 69.
  • the outlet 62 is open to the upper volume, to collect the vapor refrigerant fluid from the vapor zone 69.
  • the additional evaporator 6 has a water inlet 65, for receiving water to be cooled.
  • the water releases heat to the refrigerant fluid, resulting in an evaporation of the refrigerant fluid and a cooling of the water.
  • the vapor naturally, migrates above the liquid; thus, the refrigerant fluid naturally migrates from the liquid zone 68 to the vapor zone 69.
  • the additional evaporator 6 has a water outlet 66 for releasing the water that has been cooled.
  • the water outlet 66 of the additional evaporator 6 is connected to the water inlet 25 of the evaporator 2.
  • the water flows subsequently through the additional evaporator (for a first cooling) and then through the evaporator 2 (for a second cooling).
  • two distinct flows of water flow through the evaporator 2 and the additional evaporator 6.
  • the outlet 62 of the additional evaporator 6 is connected to the inlet 41 of the condenser 4, through a bypass branch that bypasses the compressor 3.
  • the cooling system 1 comprises a first controlled valve 71 which is arranged in the bypass branch between the outlet 62 of the additional evaporator 6 and the inlet 41 of the condenser 4.
  • the first controlled valve 71 may be an on/off valve (which has only two possible operating positions: closed and open) or may be a modulating valve (which is capable of a plurality of operating position, for modulating the flow of fluid passing there through).
  • a second conduit connects the second controlled valve 72 to the inlet 41 of the condenser 4.
  • a first conduit connects the first controlled valve 71 to the inlet 41 of the condenser 4.
  • the first and the second conduit intersect at a junction 712.
  • the additional evaporator includes an additional outlet 63.
  • the additional outlet 63 is provided at the liquid zone 68 (for collecting refrigerant fluid in the liquid phase).
  • the cooling system 1 comprises an expansion device 5.
  • the expansion device 5, in an embodiment, is an expansion valve.
  • the expansion valve is operable in an open position and in a closed position.
  • the additional outlet 63 of the additional evaporator 6 is connected to the expansion device 5.
  • the expansion device 5 receives the liquid refrigerant fluid from the additional evaporator 6, expands it and supplies it to the evaporator 2.
  • the cooling system 1 comprises a filter 81.
  • the filter 81 is arranged between the outlet 63 of the additional evaporator and the expansion device 5.
  • the additional evaporator 6, having the outlet 62 connected to the inlet 41 of the condenser 4, provides a bypass for the expansion device 5, the evaporator 2 as well as for the filter 81.
  • the cooling system 1 comprises an economizer outlet 64.
  • the economizer outlet 64 is provided at the vapor zone 69 of the additional evaporator 6.
  • the economizer outlet 64 is connected to an economizer branch, which ends into the compressor 3.
  • the cooling system 1 comprises a third controlled valve 73.
  • the third controlled valve is arranged in the economizer branch, between the economizer outlet 64 and the compressor 3.
  • the cooling system 1 comprises a control unit.
  • the control unit controls the first controlled valve 71, the second controlled valve 72, the third controlled valve 73 and the expansion valve 5.
  • the control unit is configured to operate the cooling system 1 in a traditional cooling mode.
  • the control unit opens (or keeps open) the expansion valve 5 and the second controlled valve 72, and closes (or keeps closed) the first controlled valve 71.
  • the control unit in the traditional cooling mode also opens the third controlled valve 73.
  • the control unit is configured to operate the cooling system 1 in a free-cooling mode.
  • the control unit opens (or keeps open) the first controlled valve 71 (in a first open configuration: to let the fluid flow from the outlet 62 of the additional evaporator 6 to the inlet 41 of the condenser 4) and closes (or keeps closed) the second controlled valve 72, the third controlled valve 73 and the expansion valve 5.
  • the control unit is configured to operate the system in a hybrid-cooling mode.
  • the control unit opens (or keeps open) the first controlled valve 71 (in the first open configuration), the second controlled valve 72 and the expansion valve 5.
  • the control unit closes (or keeps closed) the third controlled valve 73.
  • the control unit is configured to operate the system in a heat recovery mode.
  • the control unit opens (or keeps open) the expansion valve 5 and the second controlled valve 72 (such as in the traditional cooling mode); furthermore, the control unit opens (and keeps open) the first controlled valve 71, in a second open configuration, in which the refrigerant fluid (in the vapor phase) flows from the compressor 3 to the outlet 62 of the additional evaporator, entering the additional evaporator in the vapor phase (through the outlet 62); in this embodiment, the additional evaporator 6 works as a condenser, heating up the water that flows from the inlet 65 to the outlet 66 of the additional evaporator 6.
  • the fact that the first controlled valve 71 operates in the first open configuration (in which the refrigerant fluid flows from the outlet 62 of the additional evaporator 6 to the compressor 3), or in the second open configuration (in which the refrigerant fluid flows from the compressor 3 to the outlet 62 of the additional evaporator 6) depends essentially on the external temperature; if the external temperature is lower than the temperature of the water in the additional evaporator 6, the first controlled valve 71 operates in the first open configuration (wherein the system may operate in the hybrid mode or in the free cooling mode); conversely, if the external temperature is higher than the temperature of the water in the additional evaporator 6, the first controlled valve 71 operates in the second open configuration (wherein the system may operate in the heat recovery mode).
  • the flow of fluid flowing through the second controlled valve 72 is divided (at the junction 712) into a first fluid portion, flowing through the condenser 4, and a second fluid portion, flowing through the first controlled valve 71 towards the (outlet of) the additional evaporator 6 (which acts as a condenser).
  • the first fluid portion is significantly lower than the second fluid portion; in this case, the first fluid portion is substantially negligible and the condenser is substantially bypassed.
  • the fans 43 of the condenser 4 may be turned on (and their speed may be controlled) by the control unit; the action of the fans 43 increases the first fluid portion with respect to the second fluid portion.
  • the first controlled valve 71 may be a modulating valve, controlled by the control unit to regulate (to set) the relative amount of the second fluid portion.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Cooling Or The Like Of Electrical Apparatus (AREA)
EP19189483.1A 2018-09-18 2019-07-31 Évaporateur noyé Pending EP3627073A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT201800008690 2018-09-18

Publications (1)

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EP3627073A1 true EP3627073A1 (fr) 2020-03-25

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EP (1) EP3627073A1 (fr)

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US2016056A (en) * 1935-08-01 1935-10-01 Frick Co Liquid circulating system
US3744273A (en) 1972-03-27 1973-07-10 Trane Co Refrigeration apparatus and method of operating for powered and nonpowered cooling modes
US4843837A (en) 1986-02-25 1989-07-04 Technology Research Association Of Super Heat Pump Energy Accumulation System Heat pump system
JPH0252959A (ja) 1988-08-12 1990-02-22 Ebara Corp 冷凍機
GB2233080A (en) * 1989-03-08 1991-01-02 Star Refrigeration Refrigeration apparatus
WO2008079138A1 (fr) 2006-12-27 2008-07-03 Carrier Corporation Procédés et systèmes de commande d'une climatisation fonctionnant en mode refroidissement naturel
WO2008079118A1 (fr) 2006-12-22 2008-07-03 Carrier Corporation Systèmes et procédés de climatisation faisant appel à des séquences de démarrage de pompe en mode refroidissement naturel
WO2008079116A1 (fr) 2006-12-22 2008-07-03 Carrier Corporation Système de conditionnement d'air, et procédé comprenant des séquences de protection de pompe et refroidissement naturel
WO2009038552A1 (fr) 2007-09-18 2009-03-26 Carrier Corporation Procédés et systèmes pour contrôler des systèmes de conditionnement d'air intégrés
JP2011169532A (ja) * 2010-02-19 2011-09-01 Mitsubishi Heavy Ind Ltd 冷凍機ユニットおよびその制御方法
CN203274339U (zh) * 2013-05-08 2013-11-06 朱进 专用于化工行业单一介质梯级冷却的制冷机组
CN203501522U (zh) 2013-08-14 2014-03-26 武汉新世界制冷工业有限公司 半封闭螺杆式冷水机组
CN103925747A (zh) 2013-01-16 2014-07-16 珠海格力电器股份有限公司 满液式蒸发器及具有该蒸发器的水冷式空调机组
CN204535167U (zh) * 2015-03-10 2015-08-05 南京冷德节能科技有限公司 一种降膜式水冷螺杆低温溶液机组
US20180187932A1 (en) 2015-10-09 2018-07-05 Mitsubishi Heavy Industries Thermal Systems, Ltd. Evaporator and centrifugal chiller provided with the same

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2016056A (en) * 1935-08-01 1935-10-01 Frick Co Liquid circulating system
US3744273A (en) 1972-03-27 1973-07-10 Trane Co Refrigeration apparatus and method of operating for powered and nonpowered cooling modes
US4843837A (en) 1986-02-25 1989-07-04 Technology Research Association Of Super Heat Pump Energy Accumulation System Heat pump system
JPH0252959A (ja) 1988-08-12 1990-02-22 Ebara Corp 冷凍機
GB2233080A (en) * 1989-03-08 1991-01-02 Star Refrigeration Refrigeration apparatus
WO2008079118A1 (fr) 2006-12-22 2008-07-03 Carrier Corporation Systèmes et procédés de climatisation faisant appel à des séquences de démarrage de pompe en mode refroidissement naturel
WO2008079116A1 (fr) 2006-12-22 2008-07-03 Carrier Corporation Système de conditionnement d'air, et procédé comprenant des séquences de protection de pompe et refroidissement naturel
WO2008079138A1 (fr) 2006-12-27 2008-07-03 Carrier Corporation Procédés et systèmes de commande d'une climatisation fonctionnant en mode refroidissement naturel
WO2009038552A1 (fr) 2007-09-18 2009-03-26 Carrier Corporation Procédés et systèmes pour contrôler des systèmes de conditionnement d'air intégrés
JP2011169532A (ja) * 2010-02-19 2011-09-01 Mitsubishi Heavy Ind Ltd 冷凍機ユニットおよびその制御方法
CN103925747A (zh) 2013-01-16 2014-07-16 珠海格力电器股份有限公司 满液式蒸发器及具有该蒸发器的水冷式空调机组
CN203274339U (zh) * 2013-05-08 2013-11-06 朱进 专用于化工行业单一介质梯级冷却的制冷机组
CN203501522U (zh) 2013-08-14 2014-03-26 武汉新世界制冷工业有限公司 半封闭螺杆式冷水机组
CN204535167U (zh) * 2015-03-10 2015-08-05 南京冷德节能科技有限公司 一种降膜式水冷螺杆低温溶液机组
US20180187932A1 (en) 2015-10-09 2018-07-05 Mitsubishi Heavy Industries Thermal Systems, Ltd. Evaporator and centrifugal chiller provided with the same

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