EP2156109A1 - Procédé et système pour augmenter une marge de réglage d'un refroidisseur à absorption - Google Patents

Procédé et système pour augmenter une marge de réglage d'un refroidisseur à absorption

Info

Publication number
EP2156109A1
EP2156109A1 EP07755385A EP07755385A EP2156109A1 EP 2156109 A1 EP2156109 A1 EP 2156109A1 EP 07755385 A EP07755385 A EP 07755385A EP 07755385 A EP07755385 A EP 07755385A EP 2156109 A1 EP2156109 A1 EP 2156109A1
Authority
EP
European Patent Office
Prior art keywords
refrigerant
evaporator
generator
absorber
level
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.)
Withdrawn
Application number
EP07755385A
Other languages
German (de)
English (en)
Inventor
Sung-Han Jung
Timothy C. Wagner
Lynn M. Rog
Jin Sang Ryu
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.)
Carrier Corp
Original Assignee
Carrier Corp
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 Carrier Corp filed Critical Carrier Corp
Publication of EP2156109A1 publication Critical patent/EP2156109A1/fr
Withdrawn legal-status Critical Current

Links

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
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/04—Arrangement or mounting of control or safety devices for sorption type machines, plants or systems
    • F25B49/043—Operating continuously
    • 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
    • F25B15/00—Sorption machines, plants or systems, operating continuously, e.g. absorption type
    • 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
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • 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
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/04—Refrigerant level

Definitions

  • the present disclosure relates to an absorption chiller system. More particularly, the present disclosure relates to features for extending a turndown ratio of an absorption chiller system.
  • An absorption chiller which includes an evaporator, an absorber, a generator, and a condenser, uses an absorbent solution and a refrigerant to provide cooling and/or heating.
  • An absorption chiller may have a limited turndown ratio, which is the ratio of maximum capacity to minimum capacity. The limitations may be a function, in part, of an amount of heat source energy supplied to the generator or limited space in the absorber for excess absorbent solution. Additionally, low refrigerant levels in the evaporator may hinder the absorption chiller from achieving a higher turndown ratio.
  • the present disclosure relates to a method and system for improving operation of an absorption chiller having an evaporator, an absorber, a generator, and a condenser.
  • the disclosure relates to varying the circulation of the refrigerant and/or the absorbent solution in order to allow for continued operation of the absorption chiller during a low cooling and/or low heating demand.
  • An overflow circulation loop is configured to vary the circulation of the absorbent solution from the generator and selectively recycle excess absorbent solution from the generator to the absorber.
  • a refrigerant circulation loop is configured to vary the circulation of the refrigerant in the evaporator to prevent a refrigerant pump from running when there is less than a minimum amount of refrigerant in a sump of the evaporator.
  • the absorption chiller may be a single-effect, double-effect or triple-effect absorption chiller. In some embodiments, the absorption chiller may be capable of simultaneous heating and cooling.
  • FIG. 1 is a schematic diagram of an exemplary embodiment of an absorption chiller system that enables an extended turndown ratio.
  • FIG. 2 is a schematic diagram of a portion of the system shown in FIG. 1, illustrating use of overflow piping and a steam trap located between the absorber and the high stage generator for recycling excess absorbent solution back to the absorber.
  • FIG. 3 is a schematic of a portion of the system shown in FIG. 1, illustrating use of liquid level sensors for monitoring a refrigerant level inside the evaporator to control operation of a refrigerant pump.
  • FIG. 1 is a schematic diagram of absorption chiller system 10, which includes evaporator 12, absorber 14, high stage generator 16, low stage generator 18, condenser 20, high temperature solution heat exchanger 22, low temperature solution heat exchanger 24, and auxiliary heat exchanger 26.
  • chiller system 10 is a double-effect absorption chiller with simultaneous heating and cooling capabilities, and as such, system 10 may be used to supply heating and cooling to a building.
  • chiller system 10 may also apply to any type of absorption chiller, including, but not limited to, a single- effect or triple-effect absorption chiller, an absorption chiller configured only for cooling, and/or an absorption chiller configured for heating and cooling separately.
  • absorption chiller including, but not limited to, a single- effect or triple-effect absorption chiller, an absorption chiller configured only for cooling, and/or an absorption chiller configured for heating and cooling separately.
  • Chiller system 10 is configured to provide cooling to a building by decreasing a temperature of chilled water source 28, which passes through evaporator 12.
  • System 10 is able to simultaneously provide heating to the building by increasing a temperature of hot water source 30, which passes through auxiliary heat exchanger 26.
  • system 10 also includes cooling water loop 32 for flowing water from a cooling tower through absorber 14 and condenser 20 such that the cooling water is used for heat removal.
  • absorption chiller systems like system 10, are configured to use an absorbent solution, such as lithium bromide, and a refrigerant, such as water, to provide a cooling and/or a heating effect.
  • an absorbent solution such as lithium bromide
  • a refrigerant such as water
  • chiller system 10 is described using lithium bromide and water, it is recognized that other combinations (for example, water as the absorbent and ammonia as the refrigerant) may alternatively be used in system 10.
  • Evaporator 12 is configured to receive refrigerant in liquid form (i.e. water) from condenser 20 and store the water in evaporator sump 34.
  • evaporator 12 pumps water from sump 34 to sprayer 38, located at a top of evaporator 12, or to a dripper system in evaporator 12.
  • system 10 is a closed loop system and maintained in a vacuum such that water from sprayer 38 boils at a lower temperature.
  • the refrigerant (water), now in vaporized form, travels to absorber 14 through eliminator 40, at which point the water is absorbed by a concentrated lithium bromide solution being sprayed through sprayer 42 at a top of absorber 14.
  • a diluted lithium bromide solution then is delivered to high stage generator 16 using solution pump 44.
  • Exhaust gas is supplied to high stage generator 16 to boil water from the lithium bromide solution, thus generating steam.
  • exhaust gas is supplied from a microturbine or another type of prime mover.
  • a benefit of system 10 is that it utilizes waste heat from another component used in the building. It is recognized that other types of heat sources may be used for supplying heat energy to generator 16.
  • generator 16 may be direct-fired, steam fired or hot-water driven. Steam generated by generator 16 may then be directed to low stage generator 18 and to auxiliary heat exchanger 26. Moreover, steam from generator 16 may also reside in overflow piping 46.
  • Lithium bromide solution from high stage generator 16 flows through heat exchanger 22 and then flows to a shell side of low stage generator 18.
  • the lithium bromide solution in generator 18 then boils off additional steam due to transferred heat from the steam on the tube side of generator 18.
  • the additional steam on the shell side of generator 18 then travels to condenser 20 through eliminator 48 located between generator 18 and condenser 20.
  • cooling water 32 flows through a tube side of condenser 20.
  • the steam from generator 18 enters the shell side of condenser 20 the steam condenses and the condensate is recycled back to evaporator 12.
  • system 10 in the exemplary embodiment of FIG. 1, is a simultaneous heating and cooling absorption chiller, system 10 also includes auxiliary heat exchanger 26, which may be used for heating.
  • system 10 includes three main valves that are used to control operation of system 10 — diverter valve 70 (also referred to as CVl), heat exchanger control valve 72 (also referred to as CV2), and low stage generator control valve (also referred to as CV3).
  • Valve 70 (CVl) is configured to regulate an amount of exhaust gas supplied to high stage generator 16 based on the heating and/or cooling demands on system 10.
  • Valve 72 (C V2) is configured to regulate an amount of liquid condensate in heat exchanger 26 recycled back to generator 16, as a function of the heating demand.
  • Valve 74 (CV3) is configured to regulate an amount of liquid condensate in low stage generator 18 recycled back to evaporator 12, based on the heating and/or cooling demands and the conditions inside high stage generator 16.
  • System 10 also includes bypass loop 80, configured in parallel with heat exchanger 26, and valve 82. It is recognized that bypass loop 80 and valve 82 are not required in chiller system 10, but may be used for improving operation of system 10, particularly in an absence of a heating demand. It is recognized that an absorption chiller system may include more or less valves, as compared to the embodiment shown in FIG. 1, depending on the particular type of absorption chiller.
  • a cooling or a heating load of system 10 When a cooling or a heating load of system 10 is low, for example during mild weather conditions in the spring or fall, the load may fall below a minimum cooling or heating capacity of system 10 and system 10 may be required to shut down or enter a recycle shutdown mode.
  • a level of lithium bromide solution in high stage generator 16 may rise to an undesirable level and system 10 may shut down (or enter recycle mode). This is described in further detail below.
  • the low cooling demand may result in a depleted level of refrigerant (water) in sump 34 of evaporator 12, as also described below.
  • a low refrigerant level in evaporator sump 34 may cause refrigerant pump 36 of evaporator 12 to cavitate, and ultimately lead to destruction of pump 36.
  • Absorption chiller system 10 of FIG. 1 is configured to vary circulation of the lithium bromide solution from high stage generator 16 and to vary circulation of the refrigerant in evaporator 12, in order to allow for continued operation of absorption chiller system 10 during a low cooling demand. As such, system 10 is capable of an increased turndown (i.e. ratio of maximum capacity to minimum capacity).
  • the design features described herein and shown in FIGS. 1-3 are intended to address the above limitations that may inhibit a low turndown of system 10.
  • the design features include overflow piping 46 installed between high stage generator 16 and absorber 14, steam trap 50 installed in line with overflow piping 46, and liquid level sensors 52 for monitoring and controlling a refrigerant level in evaporator sump 34.
  • FIG. 1 as being provided in simultaneous heating and cooling absorption chiller system 10.
  • piping 46, trap 50 and sensors 52 may be incorporated into any type of absorption chiller.
  • these extended turndown features may be included in an absorption chiller that switches between a heating mode and a cooling mode, and is not configured for simultaneous heating and cooling. As described herein, the features are focused on enabling continued operation of chiller system 10 during a low cooling demand. It is recognized that piping 46, trap 50 and sensors 52 also may be used to enhance turndown during a low heating demand.
  • overflow piping 46 is connected to generator 16.
  • generator 16 During normal operation of system 10 (i.e. a moderate to high cooling and/or heating demand), as steam is boiling in generator 16 and being removed from the lithium bromide solution, the concentrated lithium bromide solution flows over a dam inside generator 16 and then to low stage generator 18 through heat exchanger 22. At this point, a portion of the steam in generator 16 may flow into overflow piping 46, to auxiliary heat exchanger 26, and to low stage generator 18.
  • a greater volume of lithium bromide solution is contained inside generator 16 and less steam is being generated.
  • System 10 has an overflow absorbent circulation loop, which includes overflow piping 46, configured to vary circulation of the absorbent solution based on the conditions in system 10, and specifically in generator 16.
  • lithium bromide solution flows from high stage generator 16 to low stage generator 18.
  • operating conditions such as a low cooling demand, exist when it may be necessary or beneficial to vary circulation of the lithium bromide solution if the absorbent solution rises above a predetermined level in the dam of high stage generator 16.
  • the excess lithium bromide solution in generator 16 is directed through overflow piping 46 back to absorber 14. This allows chiller system 10 to continue operating under conditions which may cause a greater volume of absorbent solution to reside in generator 16.
  • steam from generator 16 also may reside in overflow piping 46, system 10 includes steam trap 50 between absorber 14 and generator 16, as described in more detail below in reference to FIG. 2.
  • FIG. 2 is a schematic diagram of a portion of overflow piping 46 and steam trap 50 from FIG. 1.
  • overflow piping 46 may be used to remove excess lithium bromide solution from generator 16 and prevent an overflow of the absorbent solution inside generator 16.
  • Overflow piping 46 is configured to recycle excess lithium bromide solution in generator 16 back to absorber 14.
  • overflow piping 46 may contain steam only, lithium bromide only, or lithium bromide and steam. Because steam is useful energy, it is undesirable to allow any steam from generator 16 to flow back to absorber 14 with the absorbent solution.
  • Steam trap 50 is configured to selectively allow lithium bromide solution to recycle back to absorber 14, while preventing steam from passing through to absorber 14.
  • overflow piping 46 from generator 16 may be attached to a bottom end 50a of steam trap 50, and piping 54 extending from absorber 14 may be attached to a top end 50b of steam trap 50. The excess lithium bromide that is recycled back to absorber 14 through piping 54 may then be contained within a sump of absorber 14.
  • steam trap 50 may be an inverted bucket trap. It is recognized that other types of steam traps may alternatively be used in system 10, including, for example, thermostatic, mechanical and thermodynamic steam traps.
  • FIG. 3 is a schematic diagram of a portion of evaporator 12 and absorber 14 from FIG. 1 to illustrate a refrigerant circulation loop, which includes sensors 52, to vary circulation of refrigerant in evaporator 12.
  • the refrigerant circulation loop is configured to prevent running pump 36 when there is not enough water in sump 34.
  • refrigerant water
  • refrigerant water
  • container 56 is connected to evaporator 12 and contains liquid level sensors 52.
  • Liquid refrigerant from condenser 20 travels to evaporator 12 through piping 58 and then is contained within sump 34 and container 56.
  • a level of refrigerant in container 56 correlates to a refrigerant level in sump 34.
  • Liquid level sensors 52 are configured to sense a level of refrigerant in container 56. Sensors 52 include low level sensor 52a, high level sensor 52b and common sensor 52c.
  • Container 56 is configured such that sensors 52 may easily be removed and replaced as necessary.
  • sensors 52 are connected to a controller of system 10 that controls operation of pump 36.
  • pump 36 may be manually controlled based on signals from sensors 52.
  • a signal from sensor 52a causes the controller to abort operation of pump 36, which stops liquid refrigerant from being delivered from sump 34 to sprayer 38 through piping 60.
  • high level sensor 52b senses that a water level in sump 34 has returned to a predetermined level
  • a signal from sensor 52b results in pump 36 being restarted.
  • Common sensor 52c extends the furthest into container 56- such that a water level in sump 34 should always be above a sensing end of common sensor 52c. As such, common sensor 52c acts as a reference point for sensors 52a and 52b. It is recognized that more than three sensors may be included in container 56.
  • chiller system 10 includes overflow piping 46 (with steam trap 50) and liquid level sensors 52 in combination.
  • Overflow piping 46 and steam trap 50 vary circulation of the absorbent solution from generator 16 to allow continuous operation of chiller system 10 during a low cooling or heating demand.
  • Liquid level sensors 52 vary circulation of refrigerant in evaporator 12 to allow continuous operation of chiller system 10 during a low cooling or heating demand.
  • Overflow piping 46 and liquid level sensors 52 may be used together to vary circulation of the refrigerant and the absorbent solution, in order to increase a turndown ratio of system 10. It is recognized that a chiller system may include overflow piping 46 and steam trap 50, and exclude liquid level sensors 52; alternatively, the chiller system may include liquid level sensors 52, without overflow piping 46 and steam trap 50.
  • the overflow piping, steam trap and liquid level sensors are used in combination.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Sorption Type Refrigeration Machines (AREA)

Abstract

La présente invention concerne un procédé et un système pour améliorer le fonctionnement d'un refroidisseur à absorption doté d'un évaporateur, d'un absorbeur, d'un générateur, et d'un condenseur modifiant la circulation d'une solution réfrigérante et/ou absorbante afin de permettre le fonctionnement continu du refroidisseur à absorption durant une demande de faible refroidissement et/ou de faible chauffage. Une boucle de débordement de circulation est configurée afin de modifier la circulation de la solution absorbante et de recycler de façon sélective la solution absorbante en excès du générateur vers l'absorbeur. Une boucle de circulation réfrigérante est configurée pour modifier la circulation du frigorigène dans l'évaporateur afin d'éviter le fonctionnement d'une pompe réfrigérante lorsque l'évaporateur contient une quantité minimum de frigorigène. Le condenseur d'absorption peut être un condenseur d'absorption à effet simple, double ou triple. Dans certains modes de réalisation, le condenseur d'absorption peut être capable de chauffer et de refroidir de façon simultanée.
EP07755385A 2007-04-13 2007-04-13 Procédé et système pour augmenter une marge de réglage d'un refroidisseur à absorption Withdrawn EP2156109A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2007/009098 WO2008127236A1 (fr) 2007-04-13 2007-04-13 Procédé et système pour augmenter une marge de réglage d'un refroidisseur à absorption

Publications (1)

Publication Number Publication Date
EP2156109A1 true EP2156109A1 (fr) 2010-02-24

Family

ID=39864193

Family Applications (1)

Application Number Title Priority Date Filing Date
EP07755385A Withdrawn EP2156109A1 (fr) 2007-04-13 2007-04-13 Procédé et système pour augmenter une marge de réglage d'un refroidisseur à absorption

Country Status (4)

Country Link
EP (1) EP2156109A1 (fr)
KR (1) KR20100019422A (fr)
CN (1) CN101688704A (fr)
WO (1) WO2008127236A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101688723B1 (ko) * 2015-04-06 2016-12-21 주식회사 센추리 0.5중 효용 흡수식 냉방기 및 그를 이용한 냉난방기
CN113669956B (zh) * 2021-08-02 2023-01-20 北京工业大学 可调节发生器及其控制方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09269162A (ja) * 1996-03-29 1997-10-14 Sanyo Electric Co Ltd 吸収式冷凍機
US6550272B2 (en) * 2000-11-08 2003-04-22 Kawasaki Thermal Engineering Co., Ltd. Absorption chiller/absorption chiller-heater having safety device
US6564562B1 (en) * 2002-01-10 2003-05-20 American Standard International Inc. Generator solution outlet box for an absorption chiller

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2008127236A1 *

Also Published As

Publication number Publication date
CN101688704A (zh) 2010-03-31
WO2008127236A1 (fr) 2008-10-23
KR20100019422A (ko) 2010-02-18

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