CN1162667C - Throttle control mechanism of cross-critical CO2 refrigerating system - Google Patents
Throttle control mechanism of cross-critical CO2 refrigerating system Download PDFInfo
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- CN1162667C CN1162667C CNB031162983A CN03116298A CN1162667C CN 1162667 C CN1162667 C CN 1162667C CN B031162983 A CNB031162983 A CN B031162983A CN 03116298 A CN03116298 A CN 03116298A CN 1162667 C CN1162667 C CN 1162667C
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- pressure
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- expansion valve
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Classifications
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- 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
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
- F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide
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- 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
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/39—Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator
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- 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
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
- F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure
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- 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
- F25B2400/23—Separators
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- 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
- F25B2600/00—Control issues
- F25B2600/17—Control issues by controlling the pressure of the condenser
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Magnetically Actuated Valves (AREA)
Abstract
The present invention relates to a throttling control mechanism for a supercritical carbon dioxide refrigeration system, which mainly comprises a throttling valve, a vapor and liquid separator, an electromagnetic valve, a mixer, a thermostatic expansion valve, etc., wherein the opening degree of the thermostatic expansion valve is controlled the superheat degree of a refrigerant at an outlet of an evaporator. The functions of adjusting evaporation pressure and controlling the superheat degree of the refrigerant are achieved by the adjustment of the opening degree. The control of the pressure at a high pressure side is realized by controlling the inlet state of the refrigerant entering the thermostatic expansion valve through the on-off of the electromagnetic valve. The mechanism has the main advantages of economy and reliability. All used elements are elements with universality, and the self economical performance and the reliability of a device are favorable. The mechanism which is used not only can effectively control the evaporation pressure and enhance the heat transfer efficiency of the evaporator, but also can control the pressure at the high pressure side.
Description
Technical field:
The present invention relates to a kind of refrigeration system throttling controlling organization, particularly a kind of critical-cross carbon dioxide refrigeration system throttling controlling organization is used to control the high-pressure side of critical-cross carbon dioxide refrigeration system and the pressure of low-pressure side, belongs to refrigeration technology field.
Background technology:
At present the mankind are faced with more and more serious environmental problem, and wherein depletion of the ozone layer and greenhouse effects problem receive global concern day by day, cold-producing medium alternative extremely urgent.The CFC class refrigeration working medium of Shi Yonging damages the ozone layer in the past, though HFC class working medium commonly used does not now damage the ozone layer, greenhouse effects are obvious.Though people can make great efforts synthetic better refrigeration working medium, but because working medium is inevitably discharged, final result is that any non-nature is so the substitute materials that has damages all may for the ecological balance of the earth, therefore, the refrigeration working medium of final environment-friendly type should be unartificial synthetic natural refrigerant.Carbon dioxide is a kind of natural cold-producing medium, helps protecting environment, and the critical-cross carbon dioxide performance of refrigeration circulation is also suitable with traditional freon refrigeration circulation simultaneously, is therefore extensively thought rising.
The control characteristic of the high-low pressure of critical-cross carbon dioxide refrigeration system and our at present common compression-type refrigerating system have bigger different.We adopt subcritical cycle by compression-type refrigerating system commonly used at present, no matter be high-pressure side or low-pressure side, temperature and pressure are all closely related.In unit running process, mainly be to control evaporating pressure and temperature by regulating choke valve, improve the operating efficiency of system.For the high-pressure side, condensation temperature mainly depends on the temperature and the flow of cooling medium, condensing pressure is corresponding one by one with condensation temperature, and on high-tension side pressure is condensing pressure, therefore on high-tension side pressure depends on the temperature and the flow of cooling medium basically, does not need to control specially in system.For the critical-cross carbon dioxide system, what its high-pressure side cold-producing medium took place is not condensation process, but the cooling procedure of supercritical gas, its pressure and temperature are two independently variablees.Although therefore temperature is subjected to the qualification of cooling medium, pressure then directly is not restricted.In the critical-cross carbon dioxide refrigeration system, high side pressure can reach 70-150bar, is 7-10 times of refrigerating plant commonly used, and on high-tension side in addition pressure characteristic has very big influence for the operating efficiency of system.Therefore no matter be to consider, in the critical-cross carbon dioxide refrigeration system, all can the device of directly regulating for high side pressure be set as common subcritical cycle refrigeration system from security or from the thermal efficiency.
Controlled in order to guarantee critical-cross carbon dioxide refrigerating plant high side pressure, a kind of idea of generality is to control on high-tension side pressure with choke valve, when high side pressure is too high, increases the aperture of choke valve, and when pressure descends, then reduces aperture.But thus, then can not directly control, might cause the evaporator outlet degree of superheat too big, cause system effectiveness to descend for evaporating pressure.
Because the existence of the problems referred to above should seek to solve high side pressure and the simultaneously controlled scheme of low-pressure lateral pressure.In the prior art, Shengming Liao and Arne Jakobsen are in its paper " Shengming Liao; ArneJakobsen.Optimal heat rejection pressure in transcritical carbon dioxide airconditioning and heat pump systems.Proc.Natural Working Fluids ' 98; Oslo; 1998:301-310 ", a kind of control thought has been proposed, its core is: control on high-tension side pressure with choke valve, and the employing frequency-changeable compressor, control the frequency of compressor by the catch a cold temperature in space of impression, thereby reach the effect of control low-pressure side performance.This scheme though solved the simultaneously controlled problem of high and low pressure side to a certain extent, then can not be suitable for for the carbon dioxide refrigerating system that adopts the constant volume compressor.And the expense of frequency-changeable compressor is much higher than the constant volume compressor, so the economy of aforementioned schemes is relatively poor.
Summary of the invention:
The objective of the invention is at the deficiencies in the prior art, design provides a kind of critical-cross carbon dioxide refrigeration system that adopts the constant volume compressor that is applicable to, the throttling controlling organization that can control simultaneously its high and low pressure side pressure.
The critical-cross carbon dioxide refrigeration system throttling controlling organization that the present invention proposes is made up of choke valve, vapour liquid separator, magnetic valve, blender, heating power expansion valve.The import of choke valve links to each other with the gas cooler outlet, the vapour liquid separator import links to each other with the choke valve outlet, the outlet of vapour liquid separator then has two, wherein gaseous phase outlet links to each other with the magnetic valve import, electromagnetic valve outlet links to each other with the blender import by pipeline, and the liquid phase outlet directly links to each other with the blender import, and mixer outlet links to each other with the heating power expansion valve import, and the thermal expansion valve outlet port then links to each other with evaporator.Compressor is imported and exported and is linked to each other with the import of gas cooler with the outlet of evaporimeter respectively.Magnetic valve adopts open type.
Restricting element in the whole throttling controlling organization has choke valve and heating power expansion valve.
The aperture of heating power expansion valve is controlled by the refrigerant superheat degree of evaporator outlet.When evaporating pressure is low excessively, when the degree of superheat was excessive, the aperture of heating power expansion valve increased, and the flow of cold-producing medium increases, so evaporating pressure rises degree of superheat decline with evaporating temperature; When evaporating pressure was too high, then expansion valve suppressed the rising of evaporating pressure by reducing aperture.
The control of on high-tension side pressure then is to realize by the refrigerant condition that control enters heating power expansion valve.The high-pressure carbon dioxide that gas cooler comes out might be subcooled liquid, also might be supercritical fluid, but through the step-down of choke valve, all can become two-phase fluid and flows to gas-liquid separator.In most cases, two outlet difference trickles of gas-liquid separator and gas are to blender.Switch for magnetic valve preestablishes two controlled pressure values, and one is the upper pressure limit working value, and one is the low pressure limit working value.If the pressure overpressure upper limit working value of system high pressure side, then this moment closed electromagnetic valve, have only liquid to arrive the heating power expansion valve import by mixing chamber, this moment is under same thermal expansion valve opening, the refrigerant flow that flows through heating power expansion valve increases, thereby the refrigerant amount in the gas cooler is descended fast, cause high side pressure to descend fast.When on high-tension side pressure drops to when being lower than the low pressure limit working value, magnetic valve is opened and since arrive this moment enter the heating power expansion valve import be the two-phase system cryogen again, then the flow by heating power expansion valve descends, and makes on high-tension side pressure rise once more.
By above-mentioned control mode, when guaranteeing that low-pressure side has convenient pressure, on high-tension side pressure also is under control, and has avoided causing because of high side pressure is too high the danger of system.
The major advantage of this controlling organization is that it is economical and reliable.In this controlling organization, only utilize the economic general like this element of choke valve, heating power expansion valve, magnetic valve, gas-liquid separator, blender, so the economy of device itself and reliability are better.Though control these two variablees that intercouple of the degree of superheat of on high-tension side pressure and evaporimeter simultaneously, need to pay close attention to the stability problem of control, but because in the control strategy of the present invention, cause the switch motion of magnetic valve and predefined two controlled pressure values have a certain distance, the response of this control loop is much slower than the evaporator superheat control loop.Because the time constant of two control loops has the difference of the order of magnitude, can avoid possible control instability problem.
Description of drawings:
Fig. 1 is a critical-cross carbon dioxide refrigeration system throttling controlling organization schematic diagram of the present invention.
Among the figure, 1 is choke valve, and 2 is gas-liquid separator, and 3 is magnetic valve, and 4 is blender, and 5 is heating power expansion valve, and 6 is evaporimeter, and 7 is compressor, and 8 is gas cooler,
The specific embodiment:
Below in conjunction with accompanying drawing concrete enforcement of the present invention is further described.
As shown in Figure 1, critical-cross carbon dioxide refrigeration system throttling controlling organization of the present invention mainly comprises choke valve 1, vapour liquid separator 2, magnetic valve 3, blender 4, heating power expansion valve 5.Except that the throttling controlling organization, the critical-cross carbon dioxide refrigeration system also comprises evaporimeter 6, compressor 7 and gas cooler 8 etc.
Compressor 7 outlets link to each other with gas cooler 8 imports, gas cooler 8 outlets link to each other with choke valve 1 import, choke valve 1 outlet links to each other with vapour liquid separator 2 imports, vapour liquid separator 2 has gas phase and two outlets of liquid phase, wherein gaseous phase outlet links to each other with magnetic valve 3 imports by pipeline, magnetic valve 3 outlets are connected with blender 4 imports by pipeline, the liquid phase outlet of vapour liquid separator 2 directly links to each other with blender 4 imports, blender 4 outlets link to each other with heating power expansion valve 5 imports, heating power expansion valve 5 outlets then link to each other with evaporimeter 6 imports, and evaporimeter 6 outlets link to each other with compressor 7 imports.
Choke valve 1 adopts common copper choke valve, vapour liquid separator 2 adopts the cast iron manufacturing, magnetic valve 3 adopts open type, blender 4 adopts the cast iron manufacturing, heating power expansion valve 5 adopts F type heating power expansion valve, evaporimeter 6 and gas cooler 8 adopt the aluminum tube-strip heat exchanger, and compressor 7 adopts Reciprocting piston compressor.
Under nominal situation, compressor 8 is discharged supercritical CO 2 high pressure gas, become liquid or temperature behind the gas coming through cooler 8 than supercritical gas near environment temperature, flowing through then becomes two-phase fluid behind the choke valve 1 again, effect by gas-liquid separator 2, liquid and gas obtain separating, liquid phase directly enters blender 4, gas phase then enters mixing chamber 4 again by magnetic valve 3, the two-phase system cryogen that comes out from mixing chamber 4 flows to evaporimeter 6 by heating power expansion valve 5, and then is sucked by compressor 7.Switch for magnetic valve 3 preestablishes two controlled pressure values, and one is the upper pressure limit working value, and one is the low pressure limit working value.If the pressure overpressure upper limit working value of system high pressure side, then this moment, magnetic valve 3 cut out, have only liquid to pass through mixing chamber 4 and arrive heating power expansion valve 5 imports, this moment is under same heating power expansion valve 5 apertures, the refrigerant flow that flows through heating power expansion valve 5 increases, thereby the refrigerant amount in the gas cooler 8 is descended fast, cause high side pressure to descend fast.When on high-tension side pressure drops to when being lower than the low pressure limit working value, magnetic valve 3 is opened and since arrive this moment enter heating power expansion valve 5 imports be the two-phase system cryogen again, then the flow by heating power expansion valve 5 descends, and makes on high-tension side pressure rise once more.
The aperture of heating power expansion valve 5 is controlled by the refrigerant superheat degree of evaporimeter 6 outlets.When evaporating pressure is low excessively, when the degree of superheat was excessive, the aperture of heating power expansion valve 5 increased, and the flow of cold-producing medium increases, so evaporating pressure rises degree of superheat decline with evaporating temperature; When evaporating pressure was too high, then expansion valve 5 suppressed the rising of evaporating pressure by reducing aperture.
Claims (2)
1, a kind of critical-cross carbon dioxide refrigeration system throttling controlling organization, mainly comprise choke valve (1), vapour liquid separator (2), magnetic valve (3), blender (4), heating power expansion valve (5), it is characterized in that: choke valve (1) import links to each other with gas cooler (8) outlet, choke valve (1) outlet links to each other with vapour liquid separator (2) import, vapour liquid separator (2) has gas phase and two outlets of liquid phase, wherein gaseous phase outlet links to each other with magnetic valve (3) import by pipeline, magnetic valve (3) outlet is connected with blender (4) import by pipeline, the liquid phase outlet of vapour liquid separator (2) directly links to each other with blender (4) import, blender (4) outlet links to each other with heating power expansion valve (5) import, and heating power expansion valve (5) outlet is then joined with evaporimeter (6) import.
2, as the said critical-cross carbon dioxide refrigeration system of claim 1 throttling controlling organization, its feature is that also magnetic valve (3) adopts open type.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031162983A CN1162667C (en) | 2003-04-10 | 2003-04-10 | Throttle control mechanism of cross-critical CO2 refrigerating system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031162983A CN1162667C (en) | 2003-04-10 | 2003-04-10 | Throttle control mechanism of cross-critical CO2 refrigerating system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1441214A CN1441214A (en) | 2003-09-10 |
| CN1162667C true CN1162667C (en) | 2004-08-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB031162983A Expired - Fee Related CN1162667C (en) | 2003-04-10 | 2003-04-10 | Throttle control mechanism of cross-critical CO2 refrigerating system |
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20080022593A (en) * | 2004-06-11 | 2008-03-11 | 다이킨 고교 가부시키가이샤 | Air conditioner |
| CN1296663C (en) * | 2005-09-15 | 2007-01-24 | 上海交通大学 | Throttle orifice plate of transcritical carbon dioxide refrigerating system |
| JP5045524B2 (en) * | 2008-03-31 | 2012-10-10 | ダイキン工業株式会社 | Refrigeration equipment |
| JP2012502245A (en) * | 2008-09-05 | 2012-01-26 | ダンフォス アクチ−セルスカブ | Method for controlling the flow of refrigerant to the evaporator |
| CN101485952B (en) * | 2009-01-12 | 2012-02-08 | 清华大学 | System with transcritical carbon dioxide heat pump for providing heat to CCS |
| CN103105021B (en) * | 2013-01-22 | 2015-12-09 | 秦海涛 | CO 2the refrigerating heat pump unit of trans critical cycle and control method thereof |
| CN105890107B (en) * | 2015-02-13 | 2020-01-07 | 杭州三花研究院有限公司 | Control method of air conditioning system |
| CN106705508A (en) * | 2015-08-07 | 2017-05-24 | 丹佛斯（天津）有限公司 | Flash tank and refrigerating system |
| US20180031282A1 (en) * | 2016-07-26 | 2018-02-01 | Lg Electronics Inc. | Supercritical refrigeration cycle apparatus and method for controlling supercritical refrigeration cycle apparatus |
| US20210372678A1 (en) * | 2018-10-21 | 2021-12-02 | Proff Investment As | Cooling system |
| JP7011847B2 (en) * | 2019-12-27 | 2022-01-27 | Ｃｐｍホールディング株式会社 | Mixed refrigerant production equipment and mixed refrigerant production method |
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2003
- 2003-04-10 CN CNB031162983A patent/CN1162667C/en not_active Expired - Fee Related
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| CN1441214A (en) | 2003-09-10 |
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