Secondary loop thermal management system for co 2 heat pump air conditioner

Abstract

The present invention belongs to the technical field of thermal management of rail vehicles. Disclosed is a secondary loop thermal management system for a CO2 heat pump air conditioner, comprising: a CO2 processing module comprising a compressor, a gas cooler, a throttle valve, an evaporator and a gas-liquid separator; an outdoor air module comprising a first heat exchanger and a second heat exchanger; an indoor air module comprising a cooling plate and a heating plate, wherein the heating plate comprises a third heat exchanger and a fourth heat exchanger, and the cooling plate comprises a fifth heat exchanger and a sixth heat exchanger; a drinking water module comprising a heater; and an electrical and waste heat recovery module comprising a transformer converter, a seventh heat exchanger and a high-temperature energy storage device. According to the technical solution provided by the present invention, full energy recovery and gradient utilization of energy can be realized, so that the effects of energy conservation and environmental protection are achieved; and the economic cost of a CO2 heat pump air conditioning system of the rail vehicle can be lowered, and the use safety is improved.

Description

A secondary circuit thermal management system for CO2 heat pump air conditioning Technical Field

[0001] The present invention belongs to the technical field of rail vehicle thermal management, and in particular relates to a secondary circuit thermal management system for a CO2 heat pump air conditioner. Background Art

[0002] At present, rail vehicles have become one of the most important means of transportation for convenient travel, but they have also caused increasingly significant problems in energy consumption and carbon emissions. Therefore, it is urgent to propose new thermal management strategies to address the energy problems and carbon emission challenges faced in the cooling and heating process of rail vehicles.

[0003] In existing technologies, rail vehicles in most operating environments have been converted to electric drive, and a large number of electrical equipment often generate abundant cascade waste heat. Compared with ordinary small passenger cars, rail vehicles have a large thermal load and thermal inertia, and the waste heat they generate will also be greatly increased. If it is not recycled and reused, it will be a large part of the energy loss, which is not conducive to achieving the dual carbon goals and achieving better energy conservation and environmental protection effects. Among the rail vehicle technologies currently used, the basic thermal management strategy system function is relatively simple. It simply collects the waste heat generated and then discharges it to the outdoor environment to improve the thermal stability and safety of the rail vehicle working environment. It is obvious that a large amount of waste heat is not recovered through some method, resulting in energy waste. Energy management and cascade energy recovery and utilization on rail vehicles are important links to improve energy utilization efficiency.

[0004] Furthermore, driven by international legislation such as the Kigali Amendment to the Montreal Protocol, CO2 heat pump air conditioning systems, which offer significant advantages in low-temperature heating, have been introduced on some rail vehicles to meet the demand for new refrigerant alternatives. In current direct CO2 heat pump air conditioning systems, the CO2 refrigerant directly exchanges heat with both the indoor and outdoor environments, necessitating a high demand for CO2 piping components and stringent high-pressure resistance requirements. The typically high cost of copper piping also increases the cost of using CO2 heat pump air conditioning. Furthermore, given the numerous joints required to connect distributed thermal management equipment to the piping, failures in these joints or equipment, leading to significant leakage into the passenger compartment, pose a risk of suffocation.

[0005] In summary, in order to better utilize the excellent low-temperature heating efficiency of CO2, rail vehicles urgently need new thermal management systems and control methods to solve the technical problems mentioned above, such as insufficient waste heat recovery and utilization, high cost of using the new refrigerant CO2, and poor safety.

[0006] Summary of the Invention

[0007] The present invention aims to provide a secondary circuit thermal management system and control method for CO2 heat pump air conditioning, addressing the technical issues of insufficient waste heat recovery and the high cost of using the new refrigerant CO2 in existing technologies. The technical solution provided by this invention achieves sufficient energy recovery and cascaded energy utilization, achieving energy conservation and environmental protection. It can also reduce the economic cost of CO2 heat pump air conditioning systems for rail vehicles and improve operational safety.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides a secondary circuit thermal management system for a CO2 heat pump air conditioner, comprising:

[0010] CO2 processing module, including compressor, gas cooler, throttle valve, evaporator and gas-liquid separator;

[0011] an outdoor air module comprising a first heat exchanger and a second heat exchanger;

[0012] An indoor air module, comprising a cooling plate and a heating plate; wherein the heating plate comprises a third heat exchanger and a fourth heat exchanger, and the cooling plate comprises a fifth heat exchanger and a sixth heat exchanger;

[0013] Drinking water module, including heater;

[0014] Electrical and waste heat recovery module, including transformer converter, seventh heat exchanger and high-temperature energy storage device;

[0015] in,

[0016] In the CO2 circulation pipeline, the outlet of the compressor is connected to the inlet of the compressor through the first heat exchange channel of the gas cooler, the throttle valve, the first heat exchange channel of the evaporator, and the gas-liquid separator in sequence;

[0017] In the water circulation pipeline, the inlet of the second heat exchange channel of the gas cooler is connected to the port a of the second four-way valve, and the outlet is connected to the port a of the first four-way valve on the one hand, and is connected to the port a of the first four-way valve after passing through the fifth solenoid valve and the heater in sequence on the other hand; the b port of the first four-way valve is connected to the b port of the second four-way valve through the first heat exchanger, the c port of the first four-way valve is connected to the c port of the three-way valve, the d port of the first four-way valve is connected to the d port of the second four-way valve in sequence through the first solenoid valve and the fifth heat exchanger, and the d port of the first four-way valve is further connected to the d port of the second four-way valve in sequence through the second solenoid valve and the third heat exchanger; the inlet of the second heat exchange channel of the evaporator is connected to the c port of the second four-way valve, and the outlet is connected to the b port of the three-way valve; the a port of the three-way valve is connected to the b port of the second four-way valve through the first heat exchange channel of the seventh heat exchanger;

[0018] In the grease-oil circulation pipeline, the outlet of the second heat exchange channel of the seventh heat exchanger is connected to the inlet of the high-temperature energy storage device via the third solenoid valve and the sixth heat exchanger in sequence. The outlet of the second heat exchange channel of the seventh heat exchanger is also connected to the inlet of the high-temperature energy storage device via the fourth solenoid valve and the fourth heat exchanger in sequence. The outlet of the high-temperature energy storage device is connected to the inlet of the second heat exchange channel of the seventh heat exchanger. The outlet of the high-temperature energy storage device is also connected to the inlet of the high-temperature energy storage device via the second heat exchanger and the transformer converter in sequence.

[0019] A further improvement of the present invention is that it further comprises: a low-temperature expansion water tank;

[0020] The low-temperature expansion water tank is respectively connected to the d port and the b port of the first four-way valve.

[0021] A further improvement of the present invention is that it further comprises: a first water pump, a second water pump, a first oil pump, and a second oil pump;

[0022] The first water pump is arranged at the outlet of the second heat exchange channel of the gas cooler;

[0023] The second water pump is arranged at the outlet of the second heat exchange channel of the evaporator;

[0024] The first oil pump is arranged at the inlet of the high-temperature energy storage device;

[0025] The second oil pump is disposed at an outlet of the second heat exchange channel of the seventh heat exchanger.

[0026] A further improvement of the present invention is that

[0027] The third heat exchanger and the fourth heat exchanger of the heating plate are used to heat the passenger compartment;

[0028] The fifth heat exchanger of the refrigeration panel is used to cool the passenger compartment;

[0029] The fifth heat exchanger and the sixth heat exchanger of the refrigeration plate are used to work together to achieve dehumidification of the passenger compartment;

[0030] The cooling air outlet of the cooling plate is used to be arranged at the upper part of the vehicle compartment; the heating air outlet of the heating plate is used to be arranged at the lower part of the vehicle compartment.

[0031] A further improvement of the present invention is that

[0032] When formula (1) is satisfied, the vehicle enters the cooling mode;

[0033] Where A is the empirical coefficient; T air is the ambient air temperature; T indoor is the indoor air temperature;

[0034] In cooling mode, the first solenoid valve is open and the second solenoid valve is closed; the third solenoid valve is open or closed, and the fourth solenoid valve is open or closed; the three-way valve port b and port c are connected; the first four-way valve port c and port d are connected, and port a and port b are connected; the second four-way valve port c and port d are connected, and port a and port b are connected.

[0035] A further improvement of the present invention is that

[0036] When formula (2) is satisfied, the vehicle enters the heating mode;

[0037] Where B is the empirical coefficient; T air is the ambient air temperature; T indoor is the indoor air temperature;

[0038] In heating mode, the first solenoid valve is closed and the second solenoid valve is open; the third solenoid valve is opened or closed, and the fourth solenoid valve is opened or closed; the three-way valve ports b and c are connected; the first four-way valve ports c and b are connected, and ports a and d are connected; the second four-way valve ports c and b are connected, and ports a and d are connected.

[0039] A further improvement of the present invention is that

[0040] When formula (3) is satisfied, the vehicle enters the dehumidification mode;

[0041] Where, C is the empirical coefficient; T air is the ambient air temperature; T indoor is the indoor air temperature; d indoor is the indoor air humidity;

[0042] In the dehumidification mode, the third solenoid valve is opened, the first solenoid valve is opened; the second solenoid valve is opened or closed, and the fourth solenoid valve is opened or closed.

[0043] A further improvement of the present invention is that

[0044] When formula (4) is satisfied, the vehicle enters the waste heat recovery mode;

[0045] Where m is the empirical coefficient; T air is the ambient air temperature; T indoor is the indoor air temperature; T equi is the transformer converter temperature; P cond P is the inlet pressure of the CO2 module gas cooler; evap is the outlet pressure of the CO2 module evaporator;

[0046] In waste heat recovery mode, the fourth solenoid valve is open, the third solenoid valve is closed, the first solenoid valve is closed, and the second solenoid valve is open; ports b and c of the second four-way valve are connected, and ports a and d of the second four-way valve are connected; ports b and c of the first four-way valve are connected, and ports a and d of the first four-way valve are connected;

[0047] Under the premise of waste heat recovery mode, when formula (5) is satisfied, oil direct heating is adopted. At this time, ports c and b of the three-way valve are connected. When formula (6) is satisfied, oil and low-temperature water circuit are used for heat exchange, and heating is achieved in the form of a heat pump. At this time, ports a and b of the three-way valve are connected.

[0048] Where n is the empirical coefficient; T was is the waste heat temperature; T air is the ambient air temperature.

[0049] A further improvement of the present invention is that

[0050] When drinking water needs to be heated, the fifth solenoid valve opens;

[0051] When both the passenger compartment and drinking water need to be heated, the flow distribution ratio is allocated using formula (7);

[0052] Where, E is the empirical coefficient; T dri is the temperature of the drinking water heating tank; T indoor is the indoor air temperature; m dri is the water mass flow rate distributed to the drinking water heating circuit; m high is the total mass flow rate of the high-temperature water channel.

[0053] A further improvement of the present invention is that

[0054] When formula (8) is satisfied, the compressor frequency remains stable; when formula (8) is not satisfied and the result of the formula is less than 1, the compressor frequency is increased; when formula (8) is not satisfied and the result of the formula is greater than 3, the compressor frequency is decreased;

[0055] Where, F is the empirical coefficient; Q is the heating or cooling capacity; W is the power consumption of the compressor; P cond P is the inlet pressure of the CO2 module gas cooler; evap is the outlet pressure of the CO2 module evaporator.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The secondary circuit thermal management system provided by the present invention is specifically a modular secondary circuit thermal management system that can fully recover and cascade the energy of the modules of the waste heat utilization circuit on the rail vehicle, thereby achieving the effect of energy saving and environmental protection. In addition, in the present invention, the CO2 cycle is integrated into one module to provide total energy, and the remaining heat exchange modules in the system use water or oil for heat exchange, which can reduce the use of CO2 copper pipes and instead adopt a circulating coolant pipe with low pressure resistance requirements, so that the heat exchange medium circulating in the system becomes the currently mature coolant, reducing the economic cost of the rail vehicle CO2 heat pump air conditioning system; in addition, the secondary system switches the cooling / heating medium. Even if a pipeline failure occurs, resulting in accidental accidents such as coolant leakage, the coolant leaked into the passenger compartment will not pose a threat to the personal safety of the passengers like the leakage of CO2, thereby improving the safety of the CO2 heat pump system used on rail vehicles.

[0058] In the present invention, when the transformer converter has excess heat that needs to be recovered, it enters the waste heat recovery mode, causes the oil circuit to circulate, and allows the heat of the transformer converter to enter the indoor air module, exchange heat with the indoor air, and increase the indoor temperature.

[0059] In the present invention, when the drinking water module has a heat demand, the fifth solenoid valve is opened, and the air absorbs heat from the gas cooler of the CO2 module to reach a high temperature, and enters the drinking water module to heat the water. There is no need to design a separate water heating module. The drinking water can be heated by utilizing the waste heat of the system, thereby achieving full energy recovery and cascade utilization, and further achieving energy saving and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] FIG1 is a schematic diagram of a secondary circuit thermal management system for a CO2 heat pump air conditioner provided by an embodiment of the present invention;

[0061] The reference numerals in the figure are explained as follows: 100, CO2 treatment module; 1, compressor; 2, gas cooler; 3, throttle valve; 4, evaporator; 5, gas-liquid separator; 200, outdoor air module; 300, indoor air module; 6, third heat exchanger; 7, fourth heat exchanger; 8, fifth heat exchanger; 9, sixth heat exchanger; 10, cooling air outlet; 11, heating air outlet; 12, first solenoid valve; 13, second solenoid valve; 14, third solenoid valve; 15, fourth solenoid valve; 400, drinking water module; 16, fifth solenoid valve; 17, first water pump; 500, electrical and waste heat recovery module; 18, transformer converter; 19, seventh heat exchanger; 20, first oil pump; 21, high-temperature energy storage device; 22, second oil pump; 23, second water pump; 24, three-way valve; 25, first four-way valve; 26, second four-way valve; 27, low-temperature expansion water tank. DETAILED DESCRIPTION

[0062] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0063] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the numbers used in this manner are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatus.

[0064] The present invention is described in further detail below with reference to the accompanying drawings:

[0065] Referring to FIG1 , an embodiment of the present invention discloses a secondary circuit thermal management system for a CO2 heat pump air conditioner, comprising:

[0066] The CO2 processing module 100 includes a compressor 1, a gas cooler 2, a throttle valve 3, an evaporator 4, and a gas-liquid separator 5;

[0067] The outdoor air module 200 includes a first heat exchanger and a second heat exchanger;

[0068] The indoor air module 300 includes a cooling block and a heating block; wherein the heating block includes a third heat exchanger 6 and a fourth heat exchanger 7, and the cooling block includes a fifth heat exchanger 8 and a sixth heat exchanger 9;

[0069] Drinking water module 400, including a heater;

[0070] The electrical and waste heat recovery module 500 includes a transformer converter 18, a seventh heat exchanger 19 and a high-temperature energy storage device 21;

[0071] The outlet of the compressor 1 is connected to the inlet of the compressor 1 through the first heat exchange channel of the gas cooler 2, the throttle valve 3, the first heat exchange channel of the evaporator 4, and the gas-liquid separator 5 in sequence; in the gas cooler 2, water flows in from the port a of the second four-way valve 26, flows out from the outlet of the second heat exchange channel, and is connected to the first water pump 17. The outlet of the first water pump 17 is connected to the port a of the first four-way valve 25 on one hand, and is connected to the branch on the other hand, and is connected to the fifth solenoid valve 16, and enters The water enters the drinking water module 400 and then returns to the port a of the first four-way valve 25; the port b of the first four-way valve 25 is connected to the first heat exchanger, and the outlet of the first heat exchanger is connected to the port b of the second four-way valve 26; the port c of the first four-way valve 25 is connected to the port c of the three-way valve 24; the port d of the first four-way valve 25 has two branches, which are respectively connected to the first solenoid valve 12 and the second solenoid valve 13, and then pass through the fifth heat exchanger 8 and the third heat exchanger 6 and then merge to connect to the port d of the second four-way valve 26; in the evaporator 4, the water is discharged from the second four-way valve 26 The oil flows into the c port of the seventh heat exchanger 19 and flows out to the second water pump 23. The outlet of the second water pump 23 is connected to the b port of the three-way valve 24. The a port of the three-way valve 24 is connected to the first heat exchange channel of the seventh heat exchanger 19, and its outlet is connected to the b port of the second four-way valve 26 as a waste heat recovery branch associated with the water channel. The oil exchanges heat in the second heat exchange channel of the seventh heat exchanger 19, and the outlet is connected to the second oil pump 22. The oil pump outlet has two branches, which are connected to the third solenoid valve 14 and the fourth solenoid valve 15 respectively, and then enter the sixth heat exchanger 9 and the first heat exchanger 9 respectively. The four heat exchangers 7 converge at their outlets and enter the high-temperature energy storage device 21. The outlet of the high-temperature energy storage device 21 has two branches, one connected to the inlet of the second heat exchange channel of the seventh heat exchanger 19, and the other connected to the second heat exchanger of the outdoor air module 200. Its outlet is connected to the transformer converter 18, then enters the first oil pump 20, and returns to the inlet of the high-temperature energy storage device 21; in addition, there is a low-temperature expansion water tank 27 respectively connected to the d port and the b port of the first four-way valve 25 to achieve the purpose of controlling the water volume of the circulating water circuit.

[0072] In another embodiment of the present invention, a secondary circuit thermal management system for a CO2 heat pump air conditioner is disclosed, comprising:

[0073] The CO2 processing module 100 includes a compressor 1, a gas cooler 2, a throttle valve 3, an evaporator 4, and a gas-liquid separator 5 connected in sequence. For illustrative purposes, the CO2 processing module 100 is used to perform a transcritical cycle of CO2 to provide cooling / heating for the entire secondary loop thermal management system. The compressor 1 may be a transcritical CO2 compressor.

[0074] The outdoor air module 200 includes a first heat exchanger with a coolant as the working fluid and a second heat exchanger with a grease as the working fluid. Specifically, the outdoor air module 200 is used to achieve heat exchange between the coolant and the outdoor air in the secondary circuit thermal management system. The coolant can be water. Furthermore, the high-speed rail converter transformer must be equipped with a grease heat dissipation circuit.

[0075] The indoor air module 300 includes a cooling block and a heating block; the heating block includes a third heat exchanger 6 whose working fluid is coolant and a fourth heat exchanger 7 whose working fluid is fat oil, both of which can heat the passenger compartment; the cooling block includes a fifth heat exchanger 8 whose working fluid is coolant and a sixth heat exchanger 9 whose working fluid is fat oil, the fifth heat exchanger 8 can cool the passenger compartment, and when the fifth heat exchanger 8 and the sixth heat exchanger 9 are used in conjunction, the passenger compartment can be dehumidified to improve the comfort of the passenger compartment; further Explanatory note: the indoor air module 300 is used to meet the temperature target requirement in the cabin, which is a basic operating requirement. In a further preferred technical solution, the cooling air outlet 10 of the cooling plate is located in the upper part of the vehicle compartment. The cold air sinks downward, making the temperature in the entire vehicle compartment more evenly distributed from top to bottom, thereby achieving the purpose of improving passenger comfort. Similarly, the heating air outlet 11 of the heating plate is located in the lower part of the vehicle compartment. The hot air floats upward to achieve the same effect. With the above configuration, the effect of "hot air blowing on the feet and cold air blowing on the face" can be achieved.

[0076] The drinking water module 400 is used to heat drinking water on the rail vehicle and is a permanent heating block. Specifically, a bypass line can be drawn from the gas cooler 2 side to heat the drinking water.

[0077] The electrical and waste heat recovery module 500 is used to balance the energy recovery of the heat used by the transformer converter 18. Considering the safety of high-voltage electrical components, the circulation loop involved in this module uses grease as the working fluid to transfer heat. Specifically, the electrical and waste heat recovery module 500 includes a seventh heat exchanger 19 whose working fluid is coolant and which performs waste heat recovery. It includes a second oil pump 22 for waste heat recovery, which is used to pump grease to achieve flow in the oil circuit. It includes a first oil pump 20, which can realize the transformer converter 18 directly providing heat to the indoor air module 300 by pumping oil for circulation. It also includes a high-temperature energy storage device 21 for flexibly storing waste heat energy in the oil circuit system to solve the time domain imbalance problem in the supply and demand between waste heat production and other heat-consuming locations in the vehicle.

[0078] In addition, a low-temperature expansion water tank 27 is added to the water circulation loop to ensure that each water channel is connected to this low-temperature expansion water tank 27, so as to balance the water consumption of the entire loop. That is, the water consumption will not be too little, resulting in insufficient heat transmission, nor too much, resulting in insufficient flow of the working fluid, causing increased losses along the water channel. Therefore, the expansion water tank can reduce losses and make more full use of the heat of the loop.

[0079] The secondary circuit thermal management system for rail vehicle CO2 heat pump air conditioning provided by an embodiment of the present invention is different from the conventional primary system in that it directly discharges waste heat. The system designed by the present invention can make full use of waste heat. In addition, unlike the general primary system, the present invention integrates the circulation of transcritical CO2 into a separate CO2 processing module, and uses water in the secondary circulation system for heat exchange of heat-consuming equipment. On the one hand, since the secondary system uses water as the working fluid, the copper pipes used to carry high-pressure CO2 can be reduced, thereby reducing costs and improving economic benefits. Since the water pressure is much lower than the CO2 pipeline pressure, the valve components and the like will also reduce losses, thereby improving economy. On the other hand, since the working fluid is water, even if it leaks into the passenger compartment, there will not be too much safety hazard, and the risk of suffocation of passengers caused by excessive CO2 due to pipeline leakage can be effectively avoided.

[0080] In another embodiment of the present invention, a control method for an integrated thermal management system for a rail vehicle is disclosed. The method is based on the secondary circuit thermal management system for a CO2 heat pump air conditioner described above in the embodiment of the present invention, and includes the following steps:

[0081] The CO2 working medium is passed into the transcritical CO2 compressor for compression, temperature increase, and pressure increase. Then, the CO2 releases heat through the gas cooler 2 in the CO2 processing module 100, is throttled by the throttle valve 3, and then enters the evaporator 4 to absorb heat. The CO2 after heat exchange enters the gas-liquid separator 5 and finally returns to the compressor to complete the CO2 transcritical cycle. This cycle ensures that the gas cooler 2 can continuously provide heat and the evaporator 4 can continuously provide cooling, thereby providing stable cooling / heating to the entire secondary circuit system.

[0082] By using a secondary circuit to supply heat to the target heat user, the currently mature coolant working fluid can be used as the heat transfer working fluid of the secondary system. On the one hand, it can prevent leakage caused by pipeline failure, which threatens the safety of the occupants; on the other hand, it can reduce the use of CO2 copper pipelines, thereby saving costs and improving the economic benefits of system utilization.

[0083] In an embodiment of the present invention, Figure 1 shows a schematic diagram of the secondary circuit system, in which the short dashed line is a schematic route for the CO2 circulation; the solid line is a schematic route for the water circulation; and the dotted line is a schematic route for the fat oil circulation. According to different driving modes and the heat demand of each heat user in different time periods, the mode is switched by switching the valves in the system to achieve sufficient waste heat recovery and full utilization of energy. The following details different driving modes and corresponding control methods.

[0084] Specifically, in the embodiment of the present invention, when the rail vehicle enters the cooling mode, the bc port of the three-way valve 24 is opened, the first four-way valve 25 opens the cd port and the ab port, and the second four-way valve 26 opens the cd port and the ab port. On the one hand, the low-temperature water pump provides power for the water supply and performs low-temperature water circulation. The water exchanges heat in the evaporator 4 of the CO2 treatment module 100, absorbs the cooling capacity, and the temperature is reduced. It is pumped out by the low-temperature water pump, and the three-way valve 24 of the water circuit is switched to allow water to enter from the b port of the three-way valve 24 and flow out from the c port. The water flows to the first four-way valve 25 of the water circuit, enters from the c port of the first four-way valve 25, and flows out from the d port, so that the water flows into the cooling plate of the indoor air module 300 for heat exchange, and then flows through the second four-way valve 26, enters from the d port of the second four-way valve 26, and flows out from the c port, so that the water flows back to the evaporator 4 of the CO2 treatment module 100 and enters again. Heat exchange is carried out to complete the circulation of the evaporator 4 plate; on the other hand, the high-temperature water pump provides power for water supply to carry out high-temperature water circulation. The water exchanges heat in the gas cooler 2 of the CO2 treatment module 100 and is pumped out by the high-temperature water pump. The water flows out to the first four-way valve 25, enters from the a port of the first four-way valve 25, and flows out from the b port, so that the water flows into the heat exchanger of the outdoor air module 200 to release heat to the external environment, and then flows through the second four-way valve 26, enters from the b port of the second four-way valve 26, and flows out from the a port, so that the water flows back to the gas cooler 2 of the CO2 treatment module 100 for heat exchange again, completing the circulation of the gas cooler 2 plate.

[0085] Specifically, in the embodiment of the present invention, when the rail vehicle enters the heating mode, the bc port of the three-way valve 24 is opened, the first four-way valve 25 opens the bc port and the ad port, and the second four-way valve 26 opens the bc port and the ad port. On the one hand, the low-temperature water pump provides power for the water supply and performs low-temperature water circulation. The water exchanges heat in the evaporator 4 of the CO2 treatment module 100 and is pumped out by the low-temperature water pump. The three-way switching valve of the water circuit is switched to allow water to enter from the b port of the water circuit three-way valve 24 and flow out from the c port. The water flows to the first four-way valve 25, enters from the c port of the first four-way valve 25, and flows out from the b port, so that the water flows into the heat exchanger of the outdoor air module 200 to exchange heat with the environment, and then flows through the second four-way valve 26, enters from the b port of the second four-way valve 26, and flows out from the c port, so that the water flows back to the evaporator 4 of the CO2 treatment module 100 for re-heat exchange, completing the evaporator 4. On the other hand, the high-temperature water pump provides power for water circulation, and the water exchanges heat in the gas cooler 2 of the CO2 treatment module 100, absorbs heating energy, and its temperature rises. It is pumped out by the high-temperature water pump, and the water flows out to the first four-way valve 25, enters from the a port of the first four-way valve 25, and flows out from the d port, so that the water flows into the heating plate of the indoor air module 300 for heat exchange, and then flows through the second four-way valve 26, enters from the d port of the second four-way valve 26, and flows out from the a port, so that the water flows back to the gas cooler 2 of the CO2 treatment module 100 for heat exchange again, completing the circulation of the gas cooler 2 plate.

[0086] Specifically, in the embodiment of the present invention, the vehicle can enter the waste heat recovery mode in the heating mode; there are two ways to implement waste heat recovery: the first is that the oil circuit of the transformer converter 18 directly enters the heat exchanger in the passenger compartment to directly provide heat, at which time the fourth solenoid valve 15 is opened. The corresponding oil circuit direction is: the waste heat recovery oil pump directly pumps the oil into the indoor air module 300, exchanges heat with the passenger compartment heat exchanger to provide heat, then flows into the high-temperature energy storage module for heat storage, flows through the waste heat recovery heat exchanger (no heat exchange occurs in this heat exchanger at this time), and finally returns to the waste heat recovery compressor 1 to complete the oil cycle of direct heating;

[0087] The second method involves the waste heat recovery heat exchanger directly exchanging heat with the low-temperature water heat exchanger, transferring the heat to the heat pump, which then generates heat. In this case, the fourth solenoid valve 15 is open, the three-way valve 24 opens channels ab, and the second four-way valve 26 opens ports bc and ad. The corresponding system route is as follows: the oil from the high-temperature energy storage module enters the waste heat recovery heat exchanger, where the oil circuit exchanges heat with the low-temperature water circuit. The oil then enters the waste heat recovery oil pump, flows through the indoor air module 300, and finally returns to the high-temperature energy storage module, completing the oil circuit. However, the low-temperature water circuit undergoes a change in circulation. After heat exchange in the evaporator 4, the water enters the low-temperature water pump and is pumped to the water circuit three-way switching valve. It then enters port b of the three-way valve 24, exits port a, flows into the waste heat recovery heat exchanger for heat exchange, then enters port b of the second four-way valve 26, exits port c, and returns to the evaporator 4, completing the low-temperature water circuit.

[0088] Specifically, in an exemplary embodiment of the present invention, when formula (1) is satisfied, the vehicle enters the cooling mode, the corresponding valve openings are changed, the first solenoid valve 12 is opened, the second solenoid valve 13 is closed, the three-way valve 24 opens the bc port, and the four-way switching valve of the water channel changes direction according to the passage direction of the cooling mode described above.

[0089] Where A is the empirical coefficient (4≤A≤5, obtained from research); T air is the ambient air temperature, in K; T indoor is the indoor air temperature in K.

[0090] Specifically, as an example of an embodiment of the present invention, when formula (2) is satisfied, the vehicle enters the heating mode, the corresponding valve opening changes, the first solenoid valve 12 is closed, the second solenoid valve 13 is opened, the three-way valve 24 opens the bc port, and the four-way water switching valve changes direction according to the passage direction of the heating mode described above.

[0091] Where B is the empirical coefficient (1≤B≤2, obtained from research); T air is the ambient air temperature, in K; T indoor is the indoor air temperature in K.

[0092] Specifically, in an exemplary embodiment of the present invention, when formula (3) is satisfied, the vehicle enters the dehumidification mode. At this time, the third solenoid valve 14 is opened, the first solenoid valve 12 is also opened, and the water circuit and the oil circuit work in coordination to dehumidify the indoor air, thereby increasing the comfort of the passenger compartment.

[0093] Where, C is the empirical coefficient (4≤C≤4.5, obtained from research); T air is the ambient air temperature, in K; Tindoor is the indoor air temperature, in K; d indoor Indoor air humidity.

[0094] Specifically, in an exemplary embodiment of the present invention, when formula (4) is satisfied, the vehicle enters the waste heat recovery mode. At this time, the fourth solenoid valve 15 is opened, and the waste heat recovery oil pump is used to pump the working fluid oil for heat transfer. The heat of the transformer converter 18 itself is used to heat the air in the passenger compartment, thereby achieving the effect of not wasting heat and completing waste heat recovery.

[0095] Where m is the empirical coefficient (18≤m≤20, obtained from research); T air is the ambient air temperature, in K; T indoor is the indoor air temperature, in K; T equi is the transformer converter temperature, in K; P cond is the inlet pressure of the CO2 module gas cooler (i.e., the compressor exhaust pressure), in MPa; P evap It is the outlet pressure of the CO2 module evaporator (i.e. the compressor inlet pressure), in MPa.

[0096] The embodiment of the present invention is specifically illustrative. There are two waste heat recovery methods in the present invention (specifically, one is that the oil directly enters the indoor heat exchanger for direct heating; the other is that the oil is exchanged with the low-temperature water circuit and then heated by a heat pump). When formula (5) is satisfied, the oil direct heating method is adopted; when formula (6) is satisfied, the oil is exchanged with the low-temperature water circuit and heating is achieved by a heat pump.

[0097] Where n is the empirical coefficient (1.6≤n≤2.2, obtained from research); T was is the waste heat temperature, in K; T air is the ambient air temperature in K.

[0098] Specifically, in an exemplary embodiment of the present invention, when drinking water on a vehicle needs to be heated, the fifth solenoid valve 16 is opened to obtain a bypass branch connected to the normal circulation loop. The heat obtained by the gas cooler 2 in the CO2 processing module 100 is used to heat the drinking water at any time to meet the needs of passengers in the vehicle for hot drinking water. When both the passenger compartment and the drinking water need to be heated, the flow distribution ratio is distributed according to formula (7).

[0099] Where, E is the empirical coefficient (0.7≤E≤1.5, obtained from research); T dri is the temperature of the drinking water heating tank; T indoor is the indoor air temperature, in K; mdri is the water mass flow rate distributed to the drinking water heating circuit; m high is the total mass flow rate of the high-temperature water channel.

[0100] Specifically, in an exemplary embodiment of the present invention, when the heating / cooling capacity of the entire system is sufficient or does not meet the preset requirements, the compressor 1 will perform corresponding frequency conversion operations, increasing the frequency to increase the heating / cooling capacity of the system or reducing the frequency to reduce the power consumption of the system. When the calculated value is within the range shown in formula (8), the frequency of the compressor 1 remains stable. When it is less than 1, the compressor 1 increases the frequency to increase the heating / cooling capacity of the system; when it is greater than 3, the compressor 1 reduces the frequency, which can reduce power consumption and reduce the exhaust temperature and pressure of the compressor 1 to improve safety.

[0101] Where, F is the empirical coefficient (1.5≤F≤2.5, obtained from research); Q is the heating / cooling capacity, in kW; W is the compressor power consumption, in kW; P cond is the inlet pressure of the gas cooler of the CO2 processing module (i.e., the exhaust pressure of the compressor), in MPa; P evap It is the outlet pressure of the evaporator of the CO2 treatment module (i.e. the inlet pressure of the compressor), in MPa.

[0102] In a further preferred technical solution of the present invention, there is a high-temperature energy storage device 21 in the electrical and waste heat recovery module 500, which can temporarily store excess waste heat and can be called upon when other heat users have heat demand; if there is no heat demand for a long time, in order to balance the heat in the vehicle, a high-temperature oil pump can be used to pump the oil to the outdoor air module 200 for heat exchange with the outdoor air.

[0103] In the control method of the present invention, based on the real-time status parameters in the vehicle cabin and taking into account various indicators, the valve group in the system is adjusted to achieve the switching of cooling and heating modes and the processing of waste heat recovery, thereby achieving effective energy utilization and real-time and precise control of the temperature and humidity in the vehicle cabin.

[0104] Further explanation of the invention point of the embodiment of the present invention is that when there is waste heat that needs to be recycled, such as when the transformer converter module has excess heat that needs to be recycled, the control system enters the waste heat recovery mode, opens the first oil pump 20 and the second oil pump 22, and makes the oil circuit circulate, allowing the heat of the transformer converter module to enter the indoor air module 300, exchange heat with the indoor air, and increase the indoor temperature; similarly, when the drinking water module 400 has a heat demand, the fifth solenoid valve 16 is opened, and the air absorbs heat from the gas cooler 2 of the CO2 module to reach a high temperature, and enters the drinking water module 400 to heat the water. There is no need to design a separate water heating module. Only the waste heat of the system can be used to heat the drinking water, thereby achieving full energy recovery and cascade utilization, thereby achieving energy saving and environmental protection. In addition, the present invention integrates the CO2 cycle into one module to provide total energy, and the remaining heat exchange modules in the system use water or oil for heat exchange. The use of copper CO2 pipes can be reduced, and circulating coolant pipes with low pressure requirements can be used instead, so that the heat exchange medium circulating in the system becomes the currently mature coolant, reducing the economic cost of the CO2 heat pump air-conditioning system of the rail vehicle; in addition, the secondary system switches the cooling / heating medium. Even if a pipeline failure occurs, resulting in an accidental accident such as coolant leakage, the coolant leaked into the passenger compartment will not pose a threat to the personal safety of the passengers like the leakage of CO2, thereby improving the safety of the CO2 heat pump system on the rail vehicle. In the control method of the present invention, according to the real-time condition parameters in the car, various indicators are comprehensively considered, and the valve group in the system is adjusted to achieve the switching of the cooling and heating modes and the processing of waste heat recovery, thereby realizing the efficient use of energy and the real-time and precise control of the temperature and humidity in the car.

[0105] [Corrected 17 May 2024 in accordance with Rule 26] In summary, the embodiments of the present invention specifically disclose a secondary circuit thermal management system for a CO2 heat pump air conditioner on a rail vehicle. The integrated thermal management system comprises a CO2 processing module 100, an indoor air module 300, an outdoor air module 200, an electrical and waste heat recovery module 500, and a drinking water module 400. The technical solution provided by the embodiments of the present invention can change the type of working fluid flowing over a large area (specifically, transitioning from a CO2 system to a water circulation system) through a secondary system, thereby improving system safety, reducing the cost of using the CO2 system, and fully utilizing waste heat, thereby resolving various cost and performance issues remaining from the use of CO2 heat pump air conditioners on rail vehicles.

Claims

1. A secondary circuit thermal management system for a CO2 heat pump air conditioner, characterized in that: include: A CO2 processing module (100) comprises a compressor (1), a gas cooler (2), a throttle valve (3), an evaporator (4) and a gas-liquid separator (5); An outdoor air module (200) includes a first heat exchanger and a second heat exchanger; An indoor air module (300) comprises a cooling block and a heating block; wherein the heating block comprises a third heat exchanger (6) and a fourth heat exchanger (7), and the cooling block comprises a fifth heat exchanger (8) and a sixth heat exchanger (9); A drinking water module (400) comprising a heater; An electrical and waste heat recovery module (500) comprising a transformer converter (18), a seventh heat exchanger (19) and a high temperature energy storage device (21); in, In the CO2 circulation pipeline, the outlet of the compressor (1) is connected to the inlet of the compressor (1) via the first heat exchange channel of the gas cooler (2), the throttle valve (3), the first heat exchange channel of the evaporator (4), and the gas-liquid separator (5) in sequence; In the water circulation pipeline, the inlet of the second heat exchange channel of the gas cooler (2) is connected to the port a of the second four-way valve (26), and the outlet is connected to the port a of the first four-way valve (25) on the one hand, and is connected to the port a of the first four-way valve (25) on the other hand through the fifth solenoid valve (16) and the heater in sequence; the port b of the first four-way valve (25) is connected to the port b of the second four-way valve (26) through the first heat exchanger, the port c of the first four-way valve (25) is connected to the port c of the three-way valve (24), and the port d ... a of the first four-way valve (25) in sequence through the fifth solenoid valve (16) and the heater in sequence. The first solenoid valve (12) and the fifth heat exchanger (8) are connected to the port d of the second four-way valve (26); the port d of the first four-way valve (25) is also connected to the port d of the second four-way valve (26) via the second solenoid valve (13) and the third heat exchanger (6) in sequence; the inlet of the second heat exchange channel of the evaporator (4) is connected to the port c of the second four-way valve (26), and the outlet is connected to the port b of the three-way valve (24); the port a of the three-way valve (24) is connected to the port b of the second four-way valve (26) via the first heat exchange channel of the seventh heat exchanger (19); In the fat oil circulation pipeline, the outlet of the second heat exchange channel of the seventh heat exchanger (19) is connected to the inlet of the high-temperature energy storage device (21) via the third solenoid valve (14) and the sixth heat exchanger (9) in sequence, and the outlet of the second heat exchange channel of the seventh heat exchanger (19) is also connected to the inlet of the high-temperature energy storage device (21) via the fourth solenoid valve (15) and the fourth heat exchanger (7) in sequence; the outlet of the high-temperature energy storage device (21) is connected to the inlet of the second heat exchange channel of the seventh heat exchanger (19), and the high-temperature energy storage device (21) is connected to the inlet of the second heat exchange channel of the seventh heat exchanger (19). The outlet is also connected to the inlet of the high-temperature energy storage device (21) via the second heat exchanger and the transformer converter (18) in sequence.

2. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: Also includes: Low temperature expansion water tank (27); The low-temperature expansion water tank (27) is respectively connected to the d port and the b port of the first four-way valve (25).

3. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: It also includes: a first water pump (17), a second water pump (23), a first oil pump (20), and a second oil pump (22); The first water pump (17) is arranged at the outlet of the second heat exchange channel of the gas cooler (2); The second water pump (23) is arranged at the outlet of the second heat exchange channel of the evaporator (4); The first oil pump (20) is arranged at the inlet of the high-temperature energy storage device (21); The second oil pump (22) is arranged at the outlet of the second heat exchange channel of the seventh heat exchanger (19).

4. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: The third heat exchanger (6) and the fourth heat exchanger (7) of the heating plate are used to heat the passenger compartment; The fifth heat exchanger (8) of the refrigeration block is used to cool the passenger compartment; The fifth heat exchanger (8) and the sixth heat exchanger (9) of the refrigeration plate are used in coordination to achieve dehumidification of the passenger compartment; The cooling air outlet (10) of the cooling plate is used to be arranged at the upper part of the vehicle compartment; and the heating air outlet (11) of the heating plate is used to be arranged at the lower part of the vehicle compartment.

5. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: When formula (1) is satisfied, the vehicle enters cooling mode; Where A is the empirical coefficient; T air is the ambient air temperature; T indoor is the indoor air temperature; In the cooling mode, the first solenoid valve (12) is opened, and the second solenoid valve (13) is closed; the third solenoid valve (14) is opened or closed, and the fourth solenoid valve (15) is opened or closed; the port b and the port c of the three-way valve (24) are connected; the port c and the port d of the first four-way valve (25) are connected, and the port a and the port b are connected; the port c and the port d of the second four-way valve (26) are connected, and the port a and the port b are connected.

6. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: When formula (2) is satisfied, the vehicle enters the heating mode; Where B is the empirical coefficient; T air is the ambient air temperature; T indoor is the indoor air temperature; In the heating mode, the first solenoid valve (12) is closed, and the second solenoid valve (13) is opened; the third solenoid valve (14) is opened or closed, and the fourth solenoid valve (15) is opened or closed; the port b and the port c of the three-way valve (24) are connected; the port c and the port b of the first four-way valve (25) are connected, and the port a and the port d are connected; the port c and the port b of the second four-way valve (26) are connected, and the port a and the port d are connected.

7. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: When formula (3) is satisfied, the vehicle enters the dehumidification mode; Where C is the empirical coefficient; T air is the ambient air temperature; T indoor is the indoor air temperature; d indoor is the indoor air humidity; In the dehumidification mode, the third solenoid valve (14) is opened, and the first solenoid valve (12) is opened; the second solenoid valve (13) is opened or closed, and the fourth solenoid valve (15) is opened or closed.

8. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: When formula (4) is satisfied, the vehicle enters the waste heat recovery mode; Where m is the empirical coefficient; T air is the ambient air temperature; T indoor is the indoor air temperature; T equi is the transformer converter temperature; P cond P is the inlet pressure of the gas cooler of the CO2 processing module; evap The outlet pressure of the evaporator of the CO2 processing module; In the waste heat recovery mode, the fourth solenoid valve (15) is opened, the third solenoid valve (14) is closed, the first solenoid valve (12) is closed, and the second solenoid valve (13) is opened; the port b and the port c of the second four-way valve (26) are connected, and the port a and the port d of the second four-way valve (26) are connected; the port b and the port c of the first four-way valve (25) are connected, and the port a and the port d of the first four-way valve (25) are connected; Under the premise of waste heat recovery mode, when formula (5) is satisfied, oil direct heating is adopted, at which time, ports c and b of the three-way valve (24) are connected; when formula (6) is satisfied, oil and low-temperature water circuit heat exchange is adopted to achieve heating in the form of a heat pump, at which time, ports a and b of the three-way valve (24) are connected; Where n is the empirical coefficient; T was is the waste heat temperature; T air is the ambient air temperature.

9. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: When drinking water needs to be heated, the fifth solenoid valve (16) is opened; wherein, When both the passenger cabin and drinking water need to be heated, the flow distribution ratio is allocated by formula (7); Where, E is the empirical coefficient; T dri is the temperature of the drinking water heating tank; T indoor is the indoor air temperature; m dri is the water mass flow rate distributed to the drinking water heating circuit; m high is the total mass flow rate of the high-temperature water circuit.

10. A secondary circuit thermal management system for a CO2 heat pump air conditioner according to claim 1, characterized in that: When formula (8) is satisfied, the frequency of the compressor (1) remains stable; when formula (8) is not satisfied and the result of the formula calculation is less than 1, the frequency of the compressor (1) is increased; When formula (8) is not satisfied and the result of the calculation is greater than 3, the compressor (1) reduces the frequency; Where, F is the empirical coefficient; Q is the heating or cooling capacity; W is the power consumption of the compressor; P cond P is the inlet pressure of the gas cooler of the CO2 processing module; evap It is the outlet pressure of the evaporator of the CO2 processing module.

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