A carbon dioxide transcritical thermal management system for a hybrid locomotive

Abstract

The utility model discloses a kind of carbon dioxide transcritical heat management systems for hybrid locomotive, including refrigeration system and cold carrier system, refrigeration system and cold carrier system are connected by evaporator and exchange heat, refrigeration system includes by pipeline circulation connection's gas-liquid separator, compressor, check valve, gas cooler, high pressure valve, liquid accumulator, electronic expansion valve, evaporator, refrigeration system internal circulation carbon dioxide refrigerant;Cold carrier system includes by pipeline circulation connection's evaporator, heater, water pump and battery box, still include expansion water tank, the both ends of expansion water tank are respectively communicated with the front and rear ends of evaporator.The quick plug connector is installed on the pipeline before and after power battery box.The utility model uses carbon dioxide as refrigerant, safe, non-toxic, non-flammable, easy to obtain, low in price, the characteristics of high density and high heat transfer coefficient of CO2, small volume compressor, heat exchanger can be used, the weight of entire equipment is reduced.

Description

Technical Field

[0001] This utility model relates to the field of thermal management systems for hybrid locomotives, and more particularly to a transcritical carbon dioxide thermal management system for hybrid locomotives. Background Technology

[0002] With global warming and frequent extreme weather events becoming increasingly prominent environmental problems, green development has gradually become one of the mainstream trends in global social development. All sectors are actively promoting green transformation. The National Railway Administration has released the "Management Measures for the Elimination and Renewal of Old Railway Diesel Locomotives (Draft for Comments)," proposing that from 2035, old railway diesel locomotives should be completely phased out of the railway transportation market. Old diesel locomotives suffer from heavy pollution, high energy consumption, and high noise levels, making them unsuitable for meeting the needs of green and low-carbon railway development. Therefore, hybrid locomotives and other new energy locomotives have emerged in this context. Hybrid locomotives use a combination of a diesel engine and a battery, optimizing energy efficiency and intelligently adjusting the operating states of the diesel engine and electric motor to maintain optimal economic operation, thereby reducing energy consumption and operating costs. However, the battery thermal management and refrigeration systems of traditional hybrid locomotives currently use traditional refrigerants, such as R404A and R23 Freon refrigerants. These traditional refrigerants have high GWP (global warming potential), which can contribute to the greenhouse effect, damage the ozone layer, and harm the environment. Summary of the Invention

[0003] The technical problem solved by this utility model is to provide a transcritical carbon dioxide thermal management system that is highly efficient, compact, safe and non-toxic, and suitable for hybrid locomotives.

[0004] The technical solution adopted in this utility model is a transcritical carbon dioxide thermal management system for hybrid locomotives, including a refrigeration system and a refrigerant system. The refrigeration system and the refrigerant system are connected and exchange heat through an evaporator.

[0005] The refrigeration system includes a gas-liquid separator, compressor, check valve, gas cooler, high-pressure valve, liquid receiver, electronic expansion valve, and evaporator, all connected by a pipeline. Carbon dioxide refrigerant circulates within the refrigeration system.

[0006] The refrigerant system includes an evaporator, heater, water pump, and battery box, all connected by piping. It also includes an expansion tank, with its two ends connected to the front and rear ends of the evaporator, respectively. Quick-connect fittings are installed on the piping before and after the battery box. The heaters on the refrigerant piping are PTC high-voltage electro-liquid heaters. Ethylene glycol is used as the refrigerant.

[0007] The beneficial effects of this utility model are that it uses carbon dioxide (CO2) as a refrigerant, which is safe, non-toxic, non-flammable, readily available, and inexpensive. The high density and high heat transfer coefficient of CO2 allow for the use of small-volume compressors and heat exchangers, reducing the weight of the entire equipment. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of this utility model.

[0009] The following are the markings in the diagram: 1-Evaporator, 2-Gas-liquid separator, 3-Compressor, 4-Check valve, 5-Gas cooler, 6-High pressure valve, 7-Liquid receiver, 8-Electronic expansion valve, 10-Battery box, 11-Water pump, 12-Heater, 13-Expansion tank, 14-Quick connector. Detailed Implementation

[0010] The present invention will be further described below with reference to the accompanying drawings.

[0011] like Figure 1 As shown, the practical transcritical carbon dioxide thermal management system for hybrid locomotives consists of two parts. The first part is a refrigeration system formed by connecting the compressor 3, one-way valve 4, gas cooler 5, high-pressure valve 6, liquid receiver 7, electronic expansion valve 8, and evaporator 1 through pipelines, with carbon dioxide refrigerant circulating internally. The second part is a refrigerant system consisting of the evaporator 1, expansion tank 13, PTC high-pressure electro-liquid heater 12, water pump 11, quick connector 14, and connecting pipelines. The quick connector 14 is connected to the power battery box 10 on the user side, and the refrigerant circulates internally.

[0012] The refrigeration system is connected to the cooling system through an evaporator, and they exchange heat through the evaporator.

[0013] Its working principle is as follows: Low-temperature, low-pressure refrigerant is compressed from a low-temperature, low-pressure gas into a high-temperature, high-pressure gas by compressor 3, and then enters gas cooler 5 through one-way valve 4. The function of the one-way valve is to prevent liquid remaining in the pipeline and gas cooler 5 from entering compressor 3 after shutdown, which could cause liquid slugging in the compressor upon restart. The gas entering gas cooler 5 is cooled to high-pressure refrigerant gas at atmospheric temperature, and then throttled into a gas-liquid two-phase state by high-pressure valve 6. The refrigerant in the gas-liquid two-phase state enters liquid receiver 7, which compensates for liquid level changes caused by load variations. After that, it enters electronic expansion valve 8. The low-pressure refrigerant after throttling by electronic expansion valve 8 enters evaporator 1 for vaporization and heat exchange. The refrigeration system and the heat transfer system share the evaporator, which is a plate heat exchanger. One side of the plate heat exchanger is the refrigerant system, where the refrigerant liquid evaporates and absorbs heat, and the other side is the ethylene glycol heat transfer system. After evaporation, the refrigerant enters the gas-liquid separator, and the separated gaseous refrigerant then enters the compressor, thus completing the refrigerant cycle.

[0014] The working principle of this refrigerant system is as follows: High-temperature refrigerant from the user-side power battery box 10, connected via quick connector 14, enters the evaporator 1 for cooling after being connected to the PTC high-voltage electro-liquid heater 12 via water pump 11. During this time, the PTC high-voltage electro-liquid heater is not working; it only operates when heating the refrigerant is required in low-temperature winter conditions. After being cooled by the evaporator 1, the refrigerant then enters the user-side power battery pack 10 via quick connector 14 for cooling. The expansion tank 13 is connected to the refrigerant system pipeline and can accommodate the excess volume of ethylene glycol after thermal expansion, solving the system's pressure regulation problem and replenishing the system with ethylene glycol.

[0015] This utility model's thermal management system ensures efficient battery operation by maintaining the battery within a suitable temperature range. Compared to traditional refrigerants such as R404A and R23 Freon refrigerants, carbon dioxide, a natural working fluid, offers unique advantages. Carbon dioxide is a superior natural refrigerant with excellent environmental performance, safety, non-toxicity, non-flammability, easy availability, and low cost. The high density and high heat transfer coefficient of CO2 can reduce the size of compressors, heat exchangers, and other equipment, thus reducing the overall weight of the equipment.

Claims

1. A transcritical carbon dioxide thermal management system for hybrid locomotives, characterized in that: It includes a refrigeration system and a refrigerant system. The refrigeration system and the refrigerant system are connected and exchange heat through an evaporator. The refrigeration system includes a gas-liquid separator, compressor, check valve, gas cooler, high-pressure valve, liquid receiver, electronic expansion valve, and evaporator, all connected by a pipeline. Carbon dioxide refrigerant circulates within the refrigeration system. The refrigerant system includes an evaporator, a heater, a water pump, and a battery box, which are connected by a pipeline. It also includes an expansion tank, with its two ends connected to the front and rear ends of the evaporator, respectively.

2. The transcritical carbon dioxide thermal management system for hybrid locomotives as described in claim 1, characterized in that: The heater on the refrigerant line is a PTC high-pressure electro-liquid heater.

3. The transcritical carbon dioxide thermal management system for hybrid locomotives as described in claim 1, characterized in that: Quick-connect fittings are installed on the pipes before and after the power battery box.

4. The transcritical carbon dioxide thermal management system for hybrid locomotives as described in claim 1, characterized in that: The refrigerant used is ethylene glycol.

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