Waste heat from electric vehicles drives jet refrigeration and heating devices

Abstract

A waste heat-driven jet refrigeration and heating device for electric vehicles relates to the field of thermal management technology for new energy vehicles. It includes a three-medium heat exchanger, an intermediate heat exchanger, a compressor, and a water pump. The vehicle motor is connected to the three-medium heat exchanger via a pipeline. A water pump is installed on the pipeline between the vehicle motor and the three-medium heat exchanger, drawing coolant that has absorbed heat from the vehicle motor into the three-medium heat exchanger. The three-medium heat exchanger is connected to the primary inlet of the jet injector via a pipeline. A gas-liquid separator is connected to the other side of the jet injector. A secondary inlet below the jet injector is connected to the interior heat exchanger. A three-way valve II and a ball valve I are installed between the jet injector and the interior heat exchanger. The gas-liquid separator is connected to the interior heat exchanger via a pipeline. The intermediate heat exchanger is connected to the three-medium heat exchanger via pipelines, each equipped with a three-way valve. The intermediate heat exchanger is connected to the vehicle motor. This device reduces the number of devices and installation space, has a short heat exchange process, low heat loss, and a heat transfer coefficient 15%-30% higher than conventional heat exchangers.

Description

Technical Field

[0001] This utility model relates to the field of thermal management technology for new energy vehicles, specifically to a waste heat-driven jet refrigeration and heating device for electric vehicles. Background Technology

[0002] With the rapid development of new energy vehicles, the thermal management performance and energy efficiency of electric vehicles have become key factors affecting the vehicle's range and comfort. Existing electric vehicles generally use electrically driven compression heat pump systems or electric heating devices (PTC) for cooling and heating, but these systems suffer from the following main problems: 1. Low energy efficiency at low temperatures: Traditional heat pump systems suffer from insufficient heating capacity due to the low external air temperature and reduced evaporation pressure. To maintain the interior temperature, the system often needs to activate the electric heater, significantly increasing overall vehicle energy consumption and reducing range. 2. Waste heat not fully utilized: During operation, electric vehicles generate a large amount of low- and medium-temperature waste heat from the drive motor, power electronics module, and battery. However, existing systems often directly release this heat into the environment without effective recovery and utilization, resulting in energy waste. 3. Simple heat exchange structure and complex thermal management system: Existing systems often use single-medium heat exchangers, making it difficult to simultaneously meet the coupled heat exchange needs of the air, refrigerant, and coolant sides. This leads to complex system structures, long piping, and low energy transfer efficiency.

[0003] To improve energy efficiency and simplify system structure, some studies have introduced jet cycles to enhance system performance by utilizing the ejection effect of high-pressure refrigerant fluid. However, traditional jet cycle systems still rely on compressor drives, failing to achieve an energy-saving solution that utilizes waste heat as the driving force for jetting. Meanwhile, existing thermal management systems generally employ dual-medium heat exchangers (air-refrigerant or refrigerant-coolant), which struggle to achieve efficient heat coupling and transfer across multiple operating modes. To address this issue, a three-medium heat exchanger approach (air-CO2 refrigerant-coolant) is proposed, enabling flexible energy exchange between air, refrigerant, and coolant under different operating conditions, while simultaneously meeting the comprehensive thermal management needs of the battery, crew compartment, and waste heat source.

[0004] Patent CN202010374238.6 discloses a vehicle, its air conditioning system, and a control method thereof. This invention integrates the traditional vehicle's cooling and heating systems, reducing fuel consumption and saving interior space. By using a flash evaporator to increase enthalpy through gas replenishment, the range of temperatures that can be cooled and heated can be expanded. When parked, the system automatically activates heating and cooling modes based on the outside and inside temperatures. While driving, the heating mode switches from a heat pump system to a refrigerant-based heating system, utilizing the engine's waste heat from the heat exchange components, based on the temperature of the engine's heat exchange components. Adjusting different HVAC dampers allows for setting different modes, such as defogging, face blowing, and foot blowing. This invention reduces fuel consumption, decreases the number of parts, and saves interior space. It automatically determines the activation mode based on the outside temperature, is simple to operate, improves ease of use, provides high temperature comfort, and has low noise.

[0005] While the aforementioned patents also utilize engine waste heat exchange components for heating, the heat exchange process is long, resulting in significant heat loss and a low heat transfer coefficient. Therefore, a waste heat-driven injection cooling and heating device for electric vehicles is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a waste heat-driven jet refrigeration and heating device for electric vehicles to solve existing problems. Electric vehicles generate a lot of heat during operation. In order to utilize the waste heat of the motor more efficiently, create a comfortable driving and riding environment in the driver's cabin, reduce the power consumption of the electric vehicle's air conditioning, and improve the utilization rate of motor waste heat, it is necessary to explore a device that uses the motor waste heat as a driving heat source to drive jet refrigeration and heating to reduce the energy consumption of the compressor. At the same time, a three-medium heat exchanger is combined to improve the heat exchange efficiency of the device.

[0007] The technical solution of this utility model: An electric vehicle waste heat-driven jet refrigeration and heating device includes a three-medium heat exchanger 13, an intermediate heat exchanger 2, a compressor 1, a water pump 10, an indoor heat exchanger 6, an electric vehicle motor, an injector 9, an expansion valve 4, a three-way valve 7, and a ball valve 11. The electric vehicle motor is connected to the three-medium heat exchanger 13 via a pipe. A water pump 10 is installed on the pipe between the electric vehicle motor and the three-medium heat exchanger 13. The water pump 10 draws coolant that has absorbed heat from the electric vehicle motor into the three-medium heat exchanger 13. The three-medium heat exchanger 13 is connected to the primary inlet of the injector 9 via a pipe. A ball valve II 11 and a three-way valve III 12 are installed on the pipe. A gas-liquid separator 3 is connected to the other side of the injector 9. The secondary inlet below the ejector (9) is connected to the indoor heat exchanger (6). A three-way valve II (7) and a ball valve I (8) are installed between the ejector (9) and the indoor heat exchanger (6). The indoor heat exchanger (6) is connected to the gas-liquid separator (3) through a pipe. A three-way valve I (5) and an expansion valve (4) are installed on the pipe between the indoor heat exchanger (6) and the gas-liquid separator (3). The gas-liquid separator (3) is connected to one side of the intermediate heat exchanger (2) through a pipe. The other side of the intermediate heat exchanger 2 is connected to the compressor 1. The other end of the compressor 1 is connected to the three-medium heat exchanger (13). The intermediate heat exchanger (2) and the three-medium heat exchanger (13) are connected through a pipe. A three-way valve IV (14) is installed on the pipe. The intermediate heat exchanger (2) is connected to the car motor.

[0008] In the cooling mode, the left valve of three-way valve I (5) is closed, the left valve of three-way valve II (7) is closed, the lower valve of three-way valve III (12) is closed, and the right valve of three-way valve IV (14) is closed. At this time, the high-temperature and high-pressure gaseous refrigerant in the three-medium heat exchanger transfers heat to the air outside the vehicle and the coolant of the electric drive system. The gas-liquid mixture ejected by the injector is separated into low-temperature and low-pressure liquid refrigerant by the gas-liquid separator. The liquid refrigerant enters the indoor heat exchanger to absorb heat inside the vehicle. The low-temperature and low-pressure gaseous refrigerant separated by the gas-liquid separator is preheated by the coolant of the electric drive system and then enters the compressor to be compressed into high-temperature and high-pressure gaseous refrigerant to complete the cooling cycle.

[0009] The heating mode is to close the upper valve of three-way valve I (5), close the upper valve of three-way valve II (7), close the right valve of three-way valve III (12), and close the upper valve of three-way valve IV (14). At this time, the gas-liquid mixture ejected by the injector is separated into low-temperature and low-pressure liquid refrigerant by the gas-liquid separator. The liquid refrigerant enters the three-medium heat exchanger to absorb heat from the outside air and the coolant of the electric drive system. The low-temperature and low-pressure gaseous refrigerant separated by the gas-liquid separator is preheated by the coolant of the electric drive system. The gaseous refrigerant enters the compressor and is compressed into high-temperature and high-pressure gaseous refrigerant. The heat is transferred to the vehicle interior in the indoor heat exchanger to complete the heating cycle.

[0010] Advantages and technical effects of this utility model: The device utilizes waste heat generated during vehicle operation to drive an injector, forming a cooling or heating cycle. A three-medium heat exchanger enables efficient energy exchange between the air, refrigerant, and coolant sides, resulting in a compact structure, high energy efficiency, and superior low-temperature performance. The device uses the low-to-medium temperature waste heat generated during electric vehicle operation as the injection driving force, achieving heat energy recovery and reuse, reducing energy consumption, and improving the vehicle's range. The injection cycle structure reduces mechanical compression work through the ejection effect, improving the device's cooling and heating efficiency. The air-CO2 refrigerant-coolant three-medium heat exchanger achieves efficient energy coupling between the air, refrigerant, and liquid sides, meeting the thermal management requirements of the battery and passenger compartment. The device combines cooling and heating functions, adapting to summer and winter operating conditions, and maintaining good heating performance in low-temperature environments. The combined design of the three-medium heat exchanger and injection device simplifies piping and component layout, resulting in a more compact system structure and higher reliability. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the device structure of this utility model.

[0012] In the diagram, 1 is the compressor, 2 is the intermediate heat exchanger, 3 is the gas-liquid separator, 4 is the expansion valve, 5 is the three-way valve I, 6 is the indoor heat exchanger, 7 is the three-way valve II, 8 is the ball valve I, 9 is the ejector, 10 is the water pump, 11 is the ball valve II, 12 is the three-way valve III, 13 is the three-medium heat exchanger, and 14 is the three-way valve IV. Detailed Implementation

[0013] To further illustrate the invention, examples will be provided below.

[0014] Example 1 The device switches to cooling mode and closes the left valve of three-way valve I (5), the left valve of three-way valve II (7), the lower valve of three-way valve III (12), and the right valve of three-way valve IV (14). The coolant that has absorbed the heat of the car motor is drawn into the three-medium heat exchanger (13) by the water pump (10). The high-temperature and high-pressure refrigerant gas in the three-medium heat exchanger (13) transfers heat to the coolant and air. The refrigerant gas after releasing heat becomes a medium-temperature and high-pressure refrigerant liquid and enters the primary inlet of the ejector (9). The secondary inlet of the ejector (9) draws in the low-temperature and low-pressure gaseous refrigerant from the indoor heat exchanger (6). The primary and secondary inlets... After mixing in the injector (9), a low-temperature, low-pressure gas-liquid mixture is ejected. The gas-liquid mixture is separated into gas and liquid in the gas-liquid separator (3). The separated low-temperature, low-pressure liquid refrigerant enters the indoor heat exchanger (6) to absorb heat. The separated low-temperature, low-pressure gaseous refrigerant enters the intermediate heat exchanger (2). The hot coolant from the three-medium heat exchanger (13) enters the intermediate heat exchanger (2). The hot coolant transfers heat to the low-temperature, low-pressure gaseous refrigerant in the intermediate heat exchanger (2). The preheated gaseous refrigerant enters the compressor (1) and is compressed into a high-temperature, high-pressure gaseous refrigerant. The coolant from the intermediate heat exchanger (2) returns to the car motor to absorb heat.

[0015] Example 2 In heating mode, the upper valve of three-way valve I (5) is closed, the upper valve of three-way valve II (7) is closed, the right valve of three-way valve III (12) is closed, and the upper valve of three-way valve IV (14) is closed. The coolant that has absorbed the heat of the car motor is drawn into the three-medium heat exchanger (13) by the water pump (10). The low-temperature and low-pressure refrigerant liquid in the three-medium heat exchanger (13) absorbs the heat of the coolant and air. After absorbing the heat, the refrigerant liquid becomes a low-temperature and low-pressure refrigerant gas and enters the secondary inlet of the ejector (9). The medium-temperature and high-pressure liquid refrigerant from the indoor heat exchanger (6) enters the primary inlet of the ejector (9). The primary and secondary refrigerants are then connected. After mixing in the injector (9), a low-temperature, low-pressure gas-liquid mixture is ejected. The gas-liquid mixture is separated into gas and liquid in the gas-liquid separator (3). The separated low-temperature, low-pressure liquid refrigerant enters the three-medium heat exchanger (13) to absorb heat. The separated low-temperature, low-pressure gaseous refrigerant enters the intermediate heat exchanger (2). The hot coolant from the three-medium heat exchanger enters the intermediate heat exchanger (2). The hot coolant transfers heat to the low-temperature, low-pressure gaseous refrigerant in the intermediate heat exchanger (2). The preheated gaseous refrigerant enters the compressor (1) and is compressed into a high-temperature, high-pressure gaseous refrigerant. The coolant from the intermediate heat exchanger (2) returns to the car motor to absorb heat.

[0016] This application introduces ejector and three-medium heat exchanger components. The ejector can replace part of the compressor function by injecting refrigerant to generate negative pressure to draw in low-pressure vapor from the evaporator, and then mix and diffuse it to the condensing pressure to drive the air conditioning refrigeration cycle. Secondly, it can recover the expansion work of the refrigerant during throttling, or use the heat energy such as the waste heat of the motor to convert it into pressure energy to increase the suction pressure of the compressor and reduce the energy loss of the device. The three-medium heat exchanger integrates the functions of multiple traditional heat exchangers, reducing the number of devices and installation space. It has a short heat exchange process, low heat loss, and a heat transfer coefficient that is 15%-30% higher than that of conventional heat exchangers.

Claims

1. A waste heat-driven jet refrigeration and heating device for electric vehicles, comprising a three-medium heat exchanger (13), an intermediate heat exchanger (2), a compressor (1), a water pump (10), an indoor heat exchanger (6), an automotive motor, an injector (9), an expansion valve (4), a three-way valve, and a ball valve, characterized in that: The car motor is connected to the three-medium heat exchanger (13) via a pipe. A water pump (10) is installed between the car motor and the three-medium heat exchanger (13). The water pump (10) draws the coolant that has absorbed the heat of the car motor into the three-medium heat exchanger (13). The three-medium heat exchanger (13) is connected to the primary inlet of the ejector (9) via a pipe. A ball valve II (11) and a three-way valve III (12) are installed on the pipe. The other side of the ejector (9) is connected to the gas-liquid separator (3). The secondary inlet below the ejector (9) is connected to the indoor heat exchanger (6). A three-way valve is installed between the ejector (9) and the indoor heat exchanger (6). Valve II (7), ball valve I (8), the gas-liquid separator (3) is connected to the indoor heat exchanger (6) through a pipe, a three-way valve I (5) and an expansion valve (4) are installed on the pipe between the indoor heat exchanger (6) and the gas-liquid separator (3), the gas-liquid separator (3) is connected to one side of the intermediate heat exchanger (2) through a pipe, the other side of the intermediate heat exchanger (2) is connected to the compressor (1), the other end of the compressor (1) is connected to the three-medium heat exchanger (13); the intermediate heat exchanger (2) and the three-medium heat exchanger (13) are connected through a pipe, a three-way valve IV (14) is installed on the pipe, and the intermediate heat exchanger (2) is connected to the car motor.

2. The waste heat-driven jet refrigeration and heating device for electric vehicles according to claim 1, characterized in that: The cooling mode is to close the left valve of three-way valve I (5), close the left valve of three-way valve II (7), close the lower valve of three-way valve III (12), and close the right valve of three-way valve IV (14).

3. The waste heat-driven jet refrigeration and heating device for electric vehicles according to claim 1, characterized in that: The heating mode is to close the upper valve of three-way valve I (5), close the upper valve of three-way valve II (7), close the right valve of three-way valve III (12), and close the upper valve of three-way valve IV (14).

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