CN110530047B - Double-vortex-tube-assisted transcritical CO2System and control method thereof - Google Patents

Double-vortex-tube-assisted transcritical CO2System and control method thereof Download PDF

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CN110530047B
CN110530047B CN201910645238.2A CN201910645238A CN110530047B CN 110530047 B CN110530047 B CN 110530047B CN 201910645238 A CN201910645238 A CN 201910645238A CN 110530047 B CN110530047 B CN 110530047B
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auxiliary
vortex tube
refrigerant flow
regulating valve
flow regulating
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CN110530047A (en
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曹锋
方健珉
殷翔
王静
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Xian Jiaotong University
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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
    • F25B39/00—Evaporators; Condensers
    • F25B39/02—Evaporators
    • 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
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • F25B40/02—Subcoolers
    • 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
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • F25B40/06—Superheaters
    • 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
    • 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
    • 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

Abstract

The invention discloses a double-vortex-tube-assisted transcritical CO2 system and a control method thereof, wherein a vortex tube is used at the outlet of a gas cooler to divide a refrigerant into cold fluid and hot fluid, the hot fluid heats the other path of hot water, and the temperature in front of the valve is adjusted, so that the heating capacity of the system is further improved; a vortex tube is used at the outlet of the evaporator to divide the refrigerant into cold fluid and hot fluid, the cold fluid absorbs the environmental heat, the problem of insufficient heat absorption at the low-pressure side in a low-temperature environment is solved, and meanwhile, the suction superheat degree can be adjusted to ensure the normal work of the compressor; the system can stably run under the proper optimal exhaust pressure by using the vortex tube and the expansion valve, and can realize larger heating capacity in a low-temperature environment. The control method enables the system to be in the best working condition by adjusting the opening degrees of the refrigerant flow regulating valve and the water flow regulating valve, and realizes the high-performance operation of the system under any test working condition.

Description

Double-vortex-tube-assisted transcritical CO2System and control method thereof
Technical Field
The invention belongs to the field of transcritical carbon dioxide heat pump systems, and particularly relates to a double-vortex-tube-assisted transcritical CO2A system and a control method thereof.
Background
In the field of refrigeration and air conditioning, the replacement of an environment-friendly refrigerant is one of the hot points in recent years, carbon dioxide as a natural refrigerant has the advantages of environmental friendliness, excellent performance and particularly good performance in a heat pump system in a low-temperature environment, and the high exhaust temperature and temperature slippage caused by the transcritical cycle of the carbon dioxide make the carbon dioxide have incomparable advantages compared with other existing working media in the field of heat pump water heaters. In a subcritical system using a traditional working medium, a refrigerant is in a two-phase state with basically unchanged temperature in most regions in a condenser, hot water is heated mainly by latent heat of vaporization, the temperature of outlet water is limited by the saturation temperature of the refrigerant, in a carbon dioxide transcritical system, since the critical temperature of carbon dioxide is only 31.1 ℃, transcritical circulation is used, the exhaust side is in a supercritical state, the exhaust temperature is higher and can exceed 100 ℃, temperature slippage occurs during heat exchange with water in a gas cooler and is just matched with the temperature change of the water, the sensible heat exchange has higher heat exchange efficiency, and the temperature of outlet water is controlled by the exhaust temperature, so that the hot water can be heated to a higher target temperature at one time, and the carbon dioxide transcritical heat pump system is suitable for the field of domestic hot water.
Due to the special property of carbon dioxide in a supercritical region, the COP of a carbon dioxide transcritical circulation system has great correlation with the discharge pressure, and under a certain working condition, the optimal discharge pressure with the maximum system performance coefficient is generally correlated with the temperature of the refrigerant at the outlet of the gas cooler, so that the reduction of the temperature of the refrigerant at the outlet of the gas cooler is one of important ideas and means for reducing the optimal discharge pressure and improving the system performance. In the existing transcritical carbon dioxide heat pump water heater system, the temperature of carbon dioxide at the outlet of a gas cooler is mainly controlled by the temperature of inlet water, and when the temperature of the inlet water is higher (t)w,in>35 ℃), the carbon dioxide has higher temperature at the outlet of the gas cooler, which leads to poorer system performance, and some additional supercooling systems can improve the overall system performance, but lead to more complex and bulky systems; further, in a low temperature environment (t)air<15 ℃), the heating demand of the user is increased, but the heating capacity of the system is inevitably reduced due to the deterioration of the working condition, and although carbon dioxide is used as the refrigerant, the low-temperature heating capacity is better than other refrigerants, but the situation that the heating capacity is insufficient can still exist.
Disclosure of Invention
The invention aims to provide a double vortex tube assisted transcritical CO2The system and the control method thereof solve the technical problems.
In order to achieve the purpose, the invention adopts the following technical scheme:
double-vortex-tube-assisted transcritical CO2The system comprises a compressor, a gas cooler, an auxiliary supercooling vortex tube, an auxiliary gas cooler, an evaporator, an auxiliary superheating vortex tube, an auxiliary evaporator and an expansion valve;
the outlet of the compressor is connected with the inlet of a first channel of the gas cooler, the inlet of the auxiliary supercooling vortex tube is connected with the outlet of the first channel of the gas cooler, the hot end outlet of the auxiliary supercooling vortex tube is connected with the auxiliary gas cooler, the outlet of the auxiliary gas cooler and the cold end outlet of the auxiliary supercooling vortex tube are connected with the inlet of the expansion valve together, the outlet of the expansion valve is connected with the inlet of the evaporator, the inlet of the auxiliary superheating vortex tube is connected with the outlet of the evaporator, the cold end outlet of the auxiliary superheating vortex tube is connected with the auxiliary evaporator, and the hot end outlet of the auxiliary superheating vortex tube and the outlet of the auxiliary evaporator are connected with the inlet of the compressor together;
the auxiliary supercooling vortex tube and the auxiliary superheating vortex tube can adjust the proportion of cold fluid and hot fluid.
The auxiliary supercooling vortex tube is characterized by further comprising a first refrigerant flow regulating valve and a second refrigerant flow regulating valve, wherein the first refrigerant flow regulating valve is positioned at the outlet of the hot end of the auxiliary supercooling vortex tube, the second refrigerant flow regulating valve is positioned at the outlet of the cold end of the auxiliary supercooling vortex tube, and the first refrigerant flow regulating valve and the second refrigerant flow regulating valve are both used for regulating the flow of the refrigerant.
The auxiliary superheat vortex tube is characterized by further comprising a third refrigerant flow regulating valve and a fourth refrigerant flow regulating valve, wherein the third refrigerant flow regulating valve is positioned at the outlet of the cold end of the auxiliary superheat vortex tube, the fourth refrigerant flow regulating valve is positioned at the outlet of the hot end of the auxiliary superheat vortex tube, and the third refrigerant flow regulating valve and the fourth refrigerant flow regulating valve are both used for regulating the flow of the refrigerant.
Further, the gas cooler also comprises a first water flow regulating valve and a second water flow regulating valve, wherein the first water flow regulating valve is used for regulating the water flow entering the gas cooler, and the second water flow regulating valve is used for regulating the water flow entering the auxiliary gas cooler.
Double-vortex-tube-assisted transcritical CO2Method for controlling system, and packageThe method comprises the following steps:
carbon dioxide is compressed into supercritical gas by a compressor, enters a gas cooler to release heat to heat a path of inlet water, then enters an auxiliary super-cooling vortex tube, and is divided into two flows of cold and hot fluid to flow out;
hot carbon dioxide fluid flowing out of the hot end of the auxiliary supercooling vortex tube enters the auxiliary gas cooler and heats the other path of inlet water, then is mixed with cold carbon dioxide fluid flowing out of the cold end of the auxiliary supercooling vortex tube and throttled by the expansion valve, the throttled two-phase carbon dioxide fluid passes through the evaporator and then passes through the auxiliary superheating vortex tube, refrigerant at the outlet of the cold end of the auxiliary superheating vortex tube passes through the auxiliary evaporator and then is mixed with refrigerant at the outlet of the hot end of the auxiliary superheating vortex tube and returns to the suction side of the compressor.
Furthermore, the auxiliary supercooling vortex tube is used for adjusting the temperature of the expansion valve before the valve and increasing the heating capacity of the system;
a first refrigerant flow regulating valve is arranged at the outlet of the hot end of the auxiliary supercooling vortex tube, and a second refrigerant flow regulating valve is arranged at the outlet of the cold end of the auxiliary supercooling vortex tube;
the opening degree of the first refrigerant flow regulating valve is vc1The opening degree of the second refrigerant flow regulating valve is vc2The ratio of the opening degree of the first refrigerant flow regulating valve to the opening degree of the second refrigerant flow regulating valve is rcThe relation is as follows:
Figure BDA0002133348250000031
the pre-valve temperature of the expansion valve is texv,iAt a gas cooler exit temperature of tgc,oWhen t isgc,o>At 30 deg.C, the opening degree of the first refrigerant flow regulating valve and the opening degree of the second refrigerant flow regulating valve are regulated to increase the opening degree ratio rcWhile increasing the auxiliary gas cooler water side flow until texv,i≤25℃。
Furthermore, the auxiliary superheat vortex tube is used for adjusting the suction superheat degree and increasing the heat absorption capacity of the system in a low-temperature environment;
a third refrigerant flow regulating valve is arranged at the outlet of the cold end of the auxiliary superheated vortex tube, and a fourth refrigerant flow regulating valve is arranged at the outlet of the hot end of the auxiliary superheated vortex tube;
the opening degree of the third refrigerant flow regulating valve is vh1The opening degree of the fourth refrigerant flow rate regulating valve is vh2The ratio of the opening degree of the third refrigerant flow regulating valve to the opening degree of the fourth refrigerant flow regulating valve is rhThe relation is as follows:
Figure BDA0002133348250000041
the suction superheat of the compressor is delta t, when delta t<At 5 deg.C, the opening degree of the third refrigerant flow regulating valve and the opening degree of the fourth refrigerant flow regulating valve are regulated to increase the opening degree ratio rh(ii) a When v ish1After reaching the maximum value, the opening degree v of the fourth refrigerant flow regulating valve is reducedh2To increase the opening ratio rhTherefore, the flow of the refrigerant at the outlet of the cold end of the auxiliary superheated vortex tube is increased, and the heat absorption capacity of the refrigerant in the auxiliary evaporator is increased, so that the suction superheat degree of the compressor is increased;
ambient temperature tairWhen t isairWhen the temperature is less than or equal to minus 10 ℃, the opening v of the third refrigerant flow regulating valve is regulatedh1And the opening degree v of the fourth refrigerant flow rate regulating valveh2By increasing the opening v of the third refrigerant flow regulating valveh1To increase the opening ratio rhWhen v ish1After reaching the maximum value, the opening degree v of the fourth refrigerant flow regulating valve is reducedh2Increase rhTherefore, the flow of the refrigerant at the outlet of the cold end of the auxiliary superheated vortex tube is increased, and the heat absorption capacity of the refrigerant in the auxiliary evaporator is increased, so that the purpose of increasing the heat absorption capacity of the system in a low-temperature environment is achieved.
Furthermore, a first refrigerant flow regulating valve is arranged at the outlet of the hot end of the auxiliary supercooling vortex tube, and a second refrigerant flow regulating valve is arranged at the outlet of the cold end of the auxiliary supercooling vortex tube; a third refrigerant flow regulating valve is arranged at the outlet of the cold end of the auxiliary superheated vortex tube, and a fourth refrigerant flow regulating valve is arranged at the outlet of the hot end of the auxiliary superheated vortex tube;
the system works under the optimal working condition and obtains enough heating capacity by jointly controlling the expansion valve, the auxiliary supercooling vortex tube and the auxiliary superheating vortex tube;
water flow of m at the gas cooler1The flow rate of water at the auxiliary gas cooler is m2The water flow ratio of the gas cooler to the auxiliary gas cooler is rwThe relation is as follows:
Figure BDA0002133348250000042
initially, the first refrigerant flow regulating valve, the third refrigerant flow regulating valve and the second water flow regulating valve are all closed, and the second refrigerant flow regulating valve, the fourth refrigerant flow regulating valve and the first water flow regulating valve are all opened to enable r to be fully openedwAdjusting the expansion valve and the first water flow regulating valve to keep the outlet water temperature of the gas cooler at 60 ℃, and enabling the exhaust pressure to be the optimal exhaust pressure, wherein the system heating COP is the maximum at the moment, and the optimal exhaust pressure formula is as follows:
Popt,Liao＝(2.778-0.0157tsvor,o)texv,i+0.0381tsvor,o-9.34
wherein, tsvor,oIs the temperature of the mixed fluid at the outlet of the auxiliary superheated vortex tube, texv,iIs the pre-valve temperature, t, of the expansion valvegc,oIs the gas cooler exit temperature;
monitoring compressor discharge pressure PdisAnd gas cooler exit temperature tgc,oWhen t isgc,o>At 30 ℃, r is increasedcAnd rwUp to Texv,i≤25℃；
The expansion valve is again adjusted so that the discharge pressure is the optimum discharge pressure.
Furthermore, a first refrigerant flow regulating valve is arranged at the outlet of the hot end of the auxiliary supercooling vortex tube, and a second refrigerant flow regulating valve is arranged at the outlet of the cold end of the auxiliary supercooling vortex tube; a third refrigerant flow regulating valve is arranged at the outlet of the cold end of the auxiliary superheated vortex tube, and a fourth refrigerant flow regulating valve is arranged at the outlet of the hot end of the auxiliary superheated vortex tube;
monitoring the suction superheat delta t and the ambient temperature t of the compressorairWhen t isair<Adjusting the refrigerant adjusting valves at two ends of the auxiliary superheat vortex tube at the temperature of minus 10 ℃, and increasing the opening v of a third refrigerant flow adjusting valveh1To increase the opening ratio rhWhen v ish1After reaching the maximum value, the opening degree v of the fourth refrigerant flow regulating valve is reducedh2Increase rh(ii) a When Δ t is reached<At 5 ℃, adjusting the refrigerant adjusting valves at two ends of the auxiliary overheat vortex tube to increase rhUntil delta t is more than or equal to 5 ℃; the steps are repeated, so that the system can obtain enough heating capacity under the optimal COP.
Compared with the prior art, the invention has the following beneficial effects:
a vortex tube is used at the outlet of the gas cooler to divide the refrigerant into cold fluid and hot fluid, the hot fluid heats the other path of hot water, and the temperature in front of the valve is adjusted, so that the heating capacity of the system is further improved;
a vortex tube is used at the outlet of the evaporator to divide the refrigerant into cold fluid and hot fluid, the cold fluid absorbs the environmental heat, the problem of insufficient heat absorption at the low-pressure side in a low-temperature environment is solved, and meanwhile, the suction superheat degree can be adjusted to ensure the normal work of the compressor;
the system can stably run under the proper optimal exhaust pressure by using the vortex tube and the expansion valve, and can realize higher heating capacity in a low-temperature environment;
the control method enables the system to be in the best working condition by adjusting the opening degrees of the refrigerant flow regulating valve and the water flow regulating valve, and realizes the high-performance operation of the system under any test working condition.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a dual vortex tube assisted transcritical CO2The structure of the system is shown schematically.
The system comprises a compressor 1, a gas cooler 2, an auxiliary supercooling vortex tube 3, an auxiliary gas cooler 4, an evaporator 5, an auxiliary superheating vortex tube 6, an auxiliary evaporator 7, an expansion valve 8, a first refrigerant flow regulating valve 9, a second refrigerant flow regulating valve 10, a third refrigerant flow regulating valve 11, a fourth refrigerant flow regulating valve 12, a first water flow regulating valve 13 and a second water flow regulating valve 14.
Detailed Description
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
The following detailed description is exemplary in nature and is intended to provide further details of the invention. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention.
Referring to FIG. 1, the present invention provides a dual vortex tube assisted transcritical CO2A system, comprising: the system comprises a compressor 1, a gas cooler 2, an auxiliary super-cooling vortex tube 3, an auxiliary gas cooler 4, an evaporator 5, an auxiliary super-heating vortex tube 6, an auxiliary evaporator 7, an expansion valve 8, a first refrigerant flow regulating valve 9, a second refrigerant flow regulating valve 10, a third refrigerant flow regulating valve 11, a fourth refrigerant flow regulating valve 12, a first water flow regulating valve 13 and a second water flow regulating valve 14.
An outlet of a compressor 1 is connected with a first channel inlet of a gas cooler 2, an inlet of an auxiliary supercooling vortex tube 3 is connected with a first channel outlet of the gas cooler 2, a hot end of the outlet of the auxiliary supercooling vortex tube 3 is provided with a first refrigerant flow regulating valve 9, a cold end of the outlet of the auxiliary supercooling vortex tube 3 is provided with a second refrigerant flow regulating valve 10, a first channel inlet of the auxiliary gas cooler 4 is connected with the first refrigerant flow regulating valve 9, the first channel outlet of the auxiliary gas cooler 4 and the second refrigerant flow regulating valve 10 are jointly connected with an inlet of an expansion valve 8, an outlet of the expansion valve 8 is connected with an inlet of an evaporator 5, an inlet of an auxiliary superheating vortex tube 6 is connected with an outlet of the evaporator 5, a cold end outlet of the auxiliary superheating vortex tube 6 is provided with a third refrigerant flow regulating valve 11, and a hot end outlet of the auxiliary superheating vortex tube 6 is provided with, the inlet of the auxiliary evaporator 7 is connected with the third refrigerant flow regulating valve 11, the fourth refrigerant flow regulating valve 12 and the outlet of the auxiliary evaporator 7 are connected with the inlet of the compressor 1, and the auxiliary supercooling vortex tube 3 and the auxiliary superheating vortex tube 6 can both regulate the proportion of cold fluid and hot fluid.
The first refrigerant flow regulating valve 9, the second refrigerant flow regulating valve 10, the third refrigerant flow regulating valve 11 and the fourth refrigerant flow regulating valve 12 are all used for regulating the flow of the refrigerant;
a first water flow regulating valve 13 on the water side regulates the second passage water flow through the gas cooler 2 and a second water flow regulating valve 14 regulates the second passage water flow through the auxiliary gas cooler 4.
The invention also provides a double vortex tube assisted transcritical CO2The control method of the system comprises the following steps:
the low-temperature low-pressure refrigerant carbon dioxide is compressed by a compressor 1 to become high-temperature high-pressure supercritical gas, enters a gas cooler 2 to release heat to heat hot water, then enters an auxiliary supercooling vortex tube 3 to be divided into cold and hot two flows, the high-temperature carbon dioxide flow enters an auxiliary gas cooler 4 through a first refrigerant flow regulating valve 9 at the hot end of the auxiliary supercooling vortex tube 3 and heats the other path of water, then is mixed with the low-temperature carbon dioxide flow passing through a second refrigerant flow regulating valve 10 at the cold end of the auxiliary supercooling vortex tube 3 and throttled by an expansion valve 8, the throttled two-phase carbon dioxide flow passes through an evaporator 5 and then passes through an auxiliary superheating vortex tube 6, the refrigerant with lower temperature further absorbs environmental heat in an auxiliary evaporator 7 after passing through a third refrigerant flow regulating valve 11 at the cold end of the auxiliary superheating vortex tube 6, and then is higher in temperature than a fourth refrigerant flow regulating valve 12 at the hot Mixes back into the suction side of the compressor 1 and completes a cycle.
Auxiliary subcoolingThe vortex tube 3 is used for adjusting the pre-valve temperature of the expansion valve 8 and increasing the system heating amount, and the opening degree of the first refrigerant flow regulating valve 9 is defined as vc1The opening degree of the second refrigerant flow rate adjusting valve 10 is defined as vc2The opening ratio, which is the ratio of the opening of the first refrigerant flow rate adjustment valve 9 to the opening of the second refrigerant flow rate adjustment valve 10, is defined as rcThe relation is as follows:
Figure BDA0002133348250000081
the pre-valve temperature of the expansion valve 8 is defined as texv,iDefining the outlet temperature of the gas cooler 2 as tgc,oWhen T isgc,o>At 30 ℃, the opening v of the first refrigerant flow regulating valve 9 is increasedc1To increase the opening ratio rcWhen v isc1After reaching the maximum value, the opening v of the second refrigerant flow rate adjusting valve 10 is reducedc2Thereby increasing the flow of the refrigerant at the outlet of the hot end of the auxiliary supercooling vortex tube 3, adjusting the second water flow regulating valve 14 to increase the flow of the water side of the auxiliary gas cooler 4, increasing the heat exchange quantity in the auxiliary gas cooler 4 and increasing the heating quantity of the system until texv,i≤25℃。
The auxiliary superheat vortex tube 6 is used for adjusting the degree of superheat of suction gas and increasing the heat absorption capacity of the system. The opening degree of the third refrigerant flow regulating valve 11 is defined as vh1The fourth refrigerant flow regulating valve 12 is defined by the opening degree vh2The ratio of the opening degree of the third refrigerant flow rate adjustment valve 11 to the opening degree of the fourth refrigerant flow rate adjustment valve 12, i.e., the opening degree ratio, is defined as rhThe relation is as follows:
Figure BDA0002133348250000082
defining the suction superheat of compressor as delta t<At 5 ℃, the opening v of the third refrigerant flow regulating valve 11 is increasedh1To increase the opening ratio rhWhen v ish1After reaching the maximum value, the opening v of the fourth refrigerant flow rate adjustment valve 12 is decreasedh2To increase the opening ratio rhTherefore, the flow of the refrigerant at the outlet of the cold end of the auxiliary superheated vortex tube 6 is increased, the heat absorption capacity of the refrigerant in the auxiliary evaporator 7 is increased, and the purpose of increasing the suction superheat degree of the compressor is achieved;
defining the ambient temperature as tairWhen t isairWhen the temperature is less than or equal to minus 10 ℃, the opening v of the third refrigerant flow regulating valve 11 is regulatedh1And the opening degree v of the fourth refrigerant flow rate adjustment valve 12h2By first increasing the opening v of the third refrigerant flow regulating valve 11h1To increase the opening ratio rhWhen v ish1After reaching the maximum value, the opening v of the fourth refrigerant flow rate adjustment valve 12 is decreasedh2Increase rhTherefore, the flow of the refrigerant at the outlet of the cold end of the auxiliary superheated vortex tube 6 is increased, the heat absorption capacity of the refrigerant in the auxiliary evaporator 7 is increased, and the purpose of increasing the heat absorption capacity of the system in a low-temperature environment is achieved.
The system works under the optimal working condition and obtains enough heating quantity by jointly controlling the expansion valve 8, the auxiliary supercooling vortex tube 4 and the auxiliary superheating vortex tube 6. The water flow at the side of the gas cooler 2 is m1The flow rate of water at the side of the auxiliary gas cooler 4 is m2Defining the water flow ratio rwComprises the following steps:
Figure BDA0002133348250000091
at the beginning, the first refrigerant flow rate adjusting valve 9, the third refrigerant flow rate adjusting valve 11 and the second water flow rate adjusting valve 14 are all closed, the second refrigerant flow rate adjusting valve 10, the fourth refrigerant flow rate adjusting valve 12 and the first water flow rate adjusting valve 13 are all opened, and r is set to bewAdjusting the expansion valve 8 and the first water flow regulating valve 13 to keep the temperature of the outlet water at the side of the gas cooler 2 at 60 ℃, and setting the exhaust pressure to be the optimal exhaust pressure, namely the system heating COP is maximum at the moment, wherein the optimal exhaust pressure is expressed by
Popt,Liao＝(2.778-0.0157tsvor,o)texv,i+0.0381tsvor,o-9.34
Wherein, tsvor,oIs the temperature t of the mixed fluid at the outlet of the auxiliary superheated vortex tube 6exv,iIs in front of the expansion valve 8(ii) temperature;
monitoring the discharge pressure P of the compressor 1disAnd the outlet temperature t of the gas cooler 2gc,oWhen t isgc,o>At 30 ℃, the opening v of the first refrigerant flow regulating valve 9 is increased 9c1To increase the opening ratio rcWhen v isc1After reaching the maximum value, the opening v of the second refrigerant flow rate adjusting valve 10 is reducedc2To increase the opening ratio rcWhile simultaneously opening the second water flow rate regulating valve 14 to increase rwSo as to increase the flow of the refrigerant at the hot end outlet of the auxiliary supercooling vortex tube 3 and the flow of the water side of the auxiliary gas cooler 4 until Texv,i≤25℃；
The expansion valve 8 is again adjusted so that the discharge pressure is the optimum discharge pressure.
Monitoring the suction superheat delta t and the ambient temperature t of the compressorairWhen t isair<At the temperature of minus 10 ℃, adjusting the refrigerant adjusting valves at two ends of the auxiliary superheat vortex tube by increasing the opening v of a third refrigerant flow adjusting valve 11h1To increase the opening ratio rhWhen v ish1After reaching the maximum value, the opening v of the fourth refrigerant flow rate adjustment valve 12 is decreasedh2Increase rhI.e. increasing the flow of refrigerant through the auxiliary evaporator 7 to increase the heat absorption of the system, when at<At 5 ℃, adjusting the refrigerant adjusting valves at two ends of the auxiliary overheat vortex tube to increase rhUntil delta t is more than or equal to 5 ℃; the steps are repeated, so that the system can obtain enough heating capacity under the optimal COP.
It will be appreciated by those skilled in the art that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed above are therefore to be considered in all respects as illustrative and not restrictive. All changes which come within the scope of or equivalence to the invention are intended to be embraced therein.

Claims (7)

1. Double-vortex-tube-assisted transcritical CO2The control method of the system is characterized in that the double vortex tube assisted transcritical CO2The system comprises a compressor (1), a gas cooler (1)2) The system comprises an auxiliary supercooling vortex tube (3), an auxiliary gas cooler (4), an evaporator (5), an auxiliary superheating vortex tube (6), an auxiliary evaporator (7) and an expansion valve (8); an outlet of the compressor (1) is connected with a first channel inlet of the gas cooler (2), an inlet of the auxiliary supercooling vortex tube (3) is connected with a first channel outlet of the gas cooler (2), a hot end outlet of the auxiliary supercooling vortex tube (3) is connected with the auxiliary gas cooler (4), an outlet of the auxiliary gas cooler (4) and a cold end outlet of the auxiliary supercooling vortex tube (3) are connected with an inlet of an expansion valve (8), an outlet of the expansion valve (8) is connected with an inlet of the evaporator (5), an inlet of the auxiliary superheating vortex tube (6) is connected with an outlet of the evaporator (5), a cold end outlet of the auxiliary superheating vortex tube (6) is connected with an auxiliary evaporator (7), and a hot end outlet of the auxiliary superheating vortex tube (6) and an outlet of the auxiliary evaporator (7) are connected with an inlet of the compressor (1); the auxiliary supercooling vortex tube (3) and the auxiliary superheating vortex tube (6) can adjust the proportion of cold fluid and hot fluid;
the control method comprises the following steps:
carbon dioxide is compressed into supercritical gas by a compressor (1), enters a gas cooler (2) to release heat to heat a path of inlet water, then enters an auxiliary super-cooling vortex tube (3), and is divided into two streams of cold and hot fluid to flow out;
hot carbon dioxide fluid flowing out of the hot end of the auxiliary supercooling vortex tube (3) enters the auxiliary gas cooler (4) and heats the other path of inlet water, then is mixed with cold carbon dioxide fluid flowing out of the cold end of the auxiliary supercooling vortex tube (3) and throttled by the expansion valve (8), the throttled two-phase carbon dioxide fluid passes through the evaporator (5) and then passes through the auxiliary superheating vortex tube (6), refrigerant at the outlet of the cold end of the auxiliary superheating vortex tube (6) passes through the auxiliary evaporator (7), and then is mixed with refrigerant at the outlet of the hot end of the auxiliary superheating vortex tube (6) and returns to the gas suction side of the compressor (1);
the auxiliary supercooling vortex tube (3) is used for adjusting the temperature of the expansion valve (8) in front of the valve and increasing the heating capacity of the system;
a first refrigerant flow regulating valve (9) is arranged at the outlet of the hot end of the auxiliary supercooling vortex tube (3), and a second refrigerant flow regulating valve (10) is arranged at the outlet of the cold end of the auxiliary supercooling vortex tube (3);
first of allThe opening degree of the refrigerant flow regulating valve (9) is vc1The opening degree of the second refrigerant flow control valve (10) is vc2The ratio of the opening degree of the first refrigerant flow control valve (9) to the opening degree of the second refrigerant flow control valve (10) is rcThe relation is as follows:
Figure FDA0002583984100000021
the pre-valve temperature of the expansion valve (8) is texv，iThe outlet temperature of the gas cooler (2) is tgc，oWhen t isgc，oWhen the temperature is higher than 30 ℃, the opening degree of the first refrigerant flow regulating valve (9) and the opening degree of the second refrigerant flow regulating valve (10) are regulated, and the opening degree ratio r is increasedcWhile increasing the flow rate of the water side of the auxiliary gas cooler (4) until texv，i≤25℃。
2. The dual vortex tube assisted transcritical CO of claim 12The control method of the system is characterized in that the auxiliary superheat vortex tube (6) is used for adjusting the suction superheat degree and increasing the heat absorption capacity of the system in a low-temperature environment;
a third refrigerant flow regulating valve (11) is arranged at the outlet of the cold end of the auxiliary superheated vortex tube (6), and a fourth refrigerant flow regulating valve (12) is arranged at the outlet of the hot end of the auxiliary superheated vortex tube (6);
the opening degree of the third refrigerant flow regulating valve (11) is vh1The fourth refrigerant flow control valve (12) has an opening degree vh2The ratio of the opening degree of the third refrigerant flow control valve (11) to the opening degree of the fourth refrigerant flow control valve (12) is rhThe relation is as follows:
Figure FDA0002583984100000022
the suction superheat of the compressor is delta t, when the delta t is less than 5 ℃, the opening degree of the third refrigerant flow regulating valve (11) and the opening degree of the fourth refrigerant flow regulating valve (12) are regulated, and the opening degree ratio r is increasedh(ii) a When v ish1After reaching the maximum value, the fourth refrigerant is reducedOpening v of the flow control valve (12)h2To increase the opening ratio rhThereby increasing the refrigerant flow at the outlet of the cold end of the auxiliary superheated vortex tube (6) and increasing the heat absorption capacity of the refrigerant in the auxiliary evaporator (7) so as to increase the suction superheat degree of the compressor;
ambient temperature tairWhen t isairWhen the temperature is less than or equal to minus 10 ℃, the opening v of the third refrigerant flow regulating valve (11) is regulatedh1And the opening v of the fourth refrigerant flow control valve (12)h2First, the opening v of the third refrigerant flow control valve (11) is increasedh1To increase the opening ratio rhWhen v ish1After reaching the maximum value, the opening v of the fourth refrigerant flow regulating valve (12) is reducedh2Increase rhTherefore, the refrigerant flow at the outlet of the cold end of the auxiliary superheated vortex tube (6) is increased, and the heat absorption capacity of the refrigerant in the auxiliary evaporator (7) is increased, so that the purpose of increasing the heat absorption capacity of the system in a low-temperature environment is achieved.
3. The dual vortex tube assisted transcritical CO of claim 12The control method of the system is characterized in that a first refrigerant flow regulating valve (9) is installed at a hot end outlet of an auxiliary supercooling vortex tube (3), and a second refrigerant flow regulating valve (10) is installed at a cold end outlet of the auxiliary supercooling vortex tube (3); a third refrigerant flow regulating valve (11) is arranged at the outlet of the cold end of the auxiliary superheated vortex tube (6), and a fourth refrigerant flow regulating valve (12) is arranged at the outlet of the hot end of the auxiliary superheated vortex tube (6);
the system works in the optimal working condition and obtains enough heating capacity by jointly controlling the expansion valve (8), the auxiliary supercooling vortex tube (3) and the auxiliary superheating vortex tube (6);
the water flow at the gas cooler (2) is m1The water flow at the auxiliary gas cooler (4) is m2The water flow ratio of the gas cooler (2) to the auxiliary gas cooler (4) is rwThe relation is as follows:
Figure FDA0002583984100000031
at the beginning, the first systemThe refrigerant flow regulating valve (9), the third refrigerant flow regulating valve (11) and the second water flow regulating valve (14) are all closed, and the second refrigerant flow regulating valve (10), the fourth refrigerant flow regulating valve (12) and the first water flow regulating valve (13) are all opened to enable r to be fully openedwAdjusting the expansion valve (8) and the first water flow regulating valve (13) to keep the outlet water temperature of the gas cooler (2) at 60 ℃, and enabling the exhaust pressure to be the optimal exhaust pressure, wherein the system heating COP is the maximum, and the optimal exhaust pressure formula is as follows:
Popt，Liao＝(2.778-0.0157tsvor，o)texv，i+0.0381tsvor，o-9.34
wherein, tsvor，oIs the temperature t of the mixed fluid at the outlet of the auxiliary superheated vortex tube (6)exv，iIs the pre-valve temperature, t, of the expansion valve (8)gc，oIs the gas cooler (2) outlet temperature;
monitoring compressor discharge pressure PdisAnd the outlet temperature t of the gas cooler (2)gc，oWhen t isgc，oAt > 30 ℃, r is increasedcAnd rwUp to Texv，i≤25℃；
The expansion valve (8) is adjusted again so that the exhaust pressure is the optimum exhaust pressure.
4. The dual vortex tube assisted transcritical CO of claim 12The control method of the system is characterized in that a first refrigerant flow regulating valve (9) is installed at a hot end outlet of an auxiliary supercooling vortex tube (3), and a second refrigerant flow regulating valve (10) is installed at a cold end outlet of the auxiliary supercooling vortex tube (3); a third refrigerant flow regulating valve (11) is arranged at the outlet of the cold end of the auxiliary superheated vortex tube (6), and a fourth refrigerant flow regulating valve (12) is arranged at the outlet of the hot end of the auxiliary superheated vortex tube (6);
monitoring the suction superheat delta t and the ambient temperature t of the compressorairWhen t isairWhen the temperature is lower than minus 10 ℃, the refrigerant regulating valves at two ends of the auxiliary overheat vortex tube are regulated, and the opening v of the third refrigerant flow regulating valve (11) is increasedh1To increase the opening ratio rhWhen v ish1After the maximum value is reached, the fourth refrigerant flow is reducedOpening v of the quantity control valve (12)h2Increase rh(ii) a When delta t is less than 5 ℃, adjusting the refrigerant adjusting valves at two ends of the auxiliary superheated vortex tube to increase rhUntil delta t is more than or equal to 5 ℃; the steps are repeated, so that the system can obtain enough heating capacity under the optimal COP.
5. The dual vortex tube assisted transcritical CO of claim 12The control method of the system is characterized by further comprising a first refrigerant flow regulating valve (9) and a second refrigerant flow regulating valve (10), wherein the first refrigerant flow regulating valve (9) is located at a hot end outlet of the auxiliary supercooling vortex tube (3), the second refrigerant flow regulating valve (10) is located at a cold end outlet of the auxiliary supercooling vortex tube (3), and the first refrigerant flow regulating valve (9) and the second refrigerant flow regulating valve (10) are both used for regulating the flow of the refrigerant.
6. The dual vortex tube assisted transcritical CO of claim 12The control method of the system is characterized by further comprising a third refrigerant flow regulating valve (11) and a fourth refrigerant flow regulating valve (12), wherein the third refrigerant flow regulating valve (11) is located at the cold end outlet of the auxiliary superheated vortex tube (6), the fourth refrigerant flow regulating valve (12) is located at the hot end outlet of the auxiliary superheated vortex tube (6), and the third refrigerant flow regulating valve (11) and the fourth refrigerant flow regulating valve (12) are used for regulating the flow of the refrigerant.
7. The dual vortex tube assisted transcritical CO of claim 12The control method of the system is characterized by further comprising a first water flow regulating valve (13) and a second water flow regulating valve (14), wherein the first water flow regulating valve (13) is used for regulating the water flow entering the gas cooler (2), and the second water flow regulating valve (14) is used for regulating the water flow entering the auxiliary gas cooler (4).
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1449481A (en) * 2000-06-30 2003-10-15 瓦伊集团有限公司 Regenerative refrigeration system with mixed refrigerants
JP3969154B2 (en) * 2001-08-24 2007-09-05 株式会社デンソー Hot water storage water heater
CN101852490A (en) * 2010-05-31 2010-10-06 华北电力大学（保定） Air source carbon dioxide heat pump water heater
WO2011046458A1 (en) * 2009-10-12 2011-04-21 Oleszkiewicz Blazej The compression heat pump with thermal accelerator
CN205747569U (en) * 2016-05-09 2016-11-30 珠海格力节能环保制冷技术研究中心有限公司 A kind of air conditioning system
EP3208556A1 (en) * 2016-02-22 2017-08-23 LSIS Co., Ltd. Cooling apparatus for power converter

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1449481A (en) * 2000-06-30 2003-10-15 瓦伊集团有限公司 Regenerative refrigeration system with mixed refrigerants
JP3969154B2 (en) * 2001-08-24 2007-09-05 株式会社デンソー Hot water storage water heater
WO2011046458A1 (en) * 2009-10-12 2011-04-21 Oleszkiewicz Blazej The compression heat pump with thermal accelerator
CN101852490A (en) * 2010-05-31 2010-10-06 华北电力大学（保定） Air source carbon dioxide heat pump water heater
EP3208556A1 (en) * 2016-02-22 2017-08-23 LSIS Co., Ltd. Cooling apparatus for power converter
CN205747569U (en) * 2016-05-09 2016-11-30 珠海格力节能环保制冷技术研究中心有限公司 A kind of air conditioning system

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