Heat pump air conditioning system

Abstract

The utility model relates to a heat pump air conditioning system, and belongs to the technical field of heat management. The outlet of the compressor, the indoor condenser, the second outdoor heat exchanger and the inlet of the compressor are sequentially connected to form a heating circulation loop, and during heating, heat of the motor is transmitted to the second outdoor heat exchanger through the motor radiator; and particularly, the evaporation temperature of the second outdoor heat exchanger serving as an evaporator is improved. Therefore, heat of the motor is fully utilized, the frosting problem of the second outdoor heat exchanger can be effectively solved, the problem of poor comfort caused by defrosting at present is solved, and energy conservation of the system can be achieved due to rising of the evaporation temperature.

Description

Technical Field

[0001] The utility model relates to a heat pump air-conditioning system, belonging to the technical field of thermal management. Background Art

[0002] The heat pump air conditioning system is a device that transfers heat energy from a low-temperature system (such as the ambient atmosphere) to a heated object (such as the cab). Figure 1 、 Figure 2 As shown, it includes an outdoor heat exchanger, a compressor and an indoor heat exchanger. When cooling in the summer, the indoor heat exchanger is used as an evaporator. The high-temperature and high-pressure refrigerant gas output by the compressor first passes through the outdoor heat exchanger, and the outdoor heat exchanger dissipates heat to the environment. After the heat is dissipated by the outdoor heat exchanger and throttled by the expansion valve, the low-temperature refrigerant enters the evaporator. The low-temperature refrigerant exchanges heat with the cab environment in the evaporator to achieve the effect of lowering the cab environment temperature. The refrigerant gas then passes through the gas-liquid separator and returns to the compressor to complete the refrigeration cycle. When heating is needed in the winter, as shown in FIG. Figure 1 As shown, the indoor heat exchanger is used as a condenser. The high-temperature and high-pressure refrigerant gas output by the compressor directly enters the condenser and exchanges heat with the cab environment to achieve the purpose of heating.

[0003] When a heat pump air conditioning system is heating, the evaporation temperature of the outdoor heat exchanger is also low when the outdoor temperature is low. When the temperature drops below the dew point of the air, moisture in the air condenses on the surface of the outdoor heat exchanger. When the surface temperature of the outdoor heat exchanger drops below 0°C, the condensed moisture forms frost on the heat exchanger. As the operating time increases, the thickness of the frost increases, resulting in a decrease in the heat transfer capacity of the outdoor heat exchanger and a reduction in heating efficiency. Therefore, when the outdoor heat exchanger is frosted, it needs to be defrosted. The current defrosting method controls the heat pump air conditioning system to operate in cooling mode, that is, the indoor heat exchanger acts as the evaporator and the outdoor heat exchanger acts as the condenser. Although defrosting is possible, it affects indoor comfort. In particular, when the outdoor heat exchanger is severely frosted, frequent defrosting is required. In this case, the heat pump air conditioning system must frequently switch to cooling mode, which in turn affects the heating demand in the vehicle and reduces interior comfort. Utility Model Content

[0004] The utility model aims to provide a heat pump air-conditioning system to solve the problem that the normal heating is affected during defrosting of the existing heat pump air-conditioning system.

[0005] In order to solve the above technical problems, the utility model provides a heat pump air-conditioning system, which includes a compressor, an indoor heat exchanger and an outdoor heat exchanger, and is characterized in that it also includes a motor radiator, the outdoor heat exchanger includes a first outdoor heat exchanger and a second outdoor heat exchanger, the indoor heat exchanger includes an evaporator and an indoor condenser, the compressor outlet, the first outdoor heat exchanger, the evaporator and the compressor inlet are connected in sequence to form a refrigeration cycle loop; the compressor outlet, the indoor condenser, the second outdoor heat exchanger and the compressor inlet are connected in sequence to form a heating cycle loop, and the motor radiator is used to transfer the heat of the motor to the second outdoor heat exchanger.

[0006] Furthermore, the motor radiator is arranged between the first outdoor heat exchanger and the second outdoor heat exchanger.

[0007] Furthermore, the motor radiator, the first outdoor heat exchanger and the second outdoor heat exchanger are integrated.

[0008] Furthermore, the first outdoor heat exchanger and the second outdoor heat exchanger share a cooling fan, and the wind direction when the cooling fans used by the first outdoor heat exchanger, the motor radiator and the second outdoor heat exchanger are started is: from the first outdoor heat exchanger to the motor radiator, and then from the motor radiator to the second outdoor heat exchanger.

[0009] Furthermore, a first switch valve is provided on the heating cycle circuit for controlling the conduction of the heating cycle circuit when there is a heating demand; a second switch valve is provided on the refrigeration cycle circuit for controlling the conduction of the refrigeration cycle circuit when there is a cooling demand.

[0010] Furthermore, both the heating cycle and the refrigeration cycle are provided with electronic expansion valves.

[0011] Furthermore, the compressor outlet and the evaporator outlet in the heating cycle are both provided with temperature sensors and pressure sensors.

[0012] The beneficial effects of this utility model are as follows: As an improved invention, this utility model sequentially connects the compressor outlet, indoor condenser, second outdoor heat exchanger, and compressor inlet to form a heating circuit. During heating, the motor heat sink is used to transfer motor heat to the second outdoor heat exchanger, thereby increasing the ambient temperature around the second outdoor heat exchanger, particularly the evaporation temperature of the second outdoor heat exchanger as an evaporator. Therefore, this utility model fully utilizes the motor heat, effectively solving the problem of frosting on the second outdoor heat exchanger and the current problem of poor comfort caused by defrosting. It also achieves energy savings due to the increased evaporation temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the principle of the existing heat pump air conditioning system when heating;

[0014] Figure 2 This is a schematic diagram of the cooling principle of an existing heat pump air conditioning system;

[0015] Figure 3 This is a schematic diagram of the principle of the heat pump air conditioning system of the utility model during heating;

[0016] Figure 4 It is a schematic diagram of the principle of the heat pump air-conditioning system of the utility model during cooling. DETAILED DESCRIPTION

[0017] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0018] Heat pump air conditioning system embodiment

[0019] This utility model sequentially connects the compressor outlet, indoor condenser, second outdoor heat exchanger, and compressor inlet to form a heating circuit. During heating, the motor heat sink transfers motor heat to the second outdoor heat exchanger, raising the ambient temperature around the second outdoor heat exchanger, particularly the evaporation temperature of the second outdoor heat exchanger, which serves as the evaporator. Therefore, this utility model fully utilizes the motor heat, effectively solving the problem of frosting on the second outdoor heat exchanger and achieving energy savings due to the increased evaporation temperature.

[0020] Specifically, if Figure 3 As shown, the heat pump air conditioning system includes a compressor, an indoor heat exchanger and an outdoor heat exchanger, wherein the indoor heat exchanger adopts an HVAC (Heating Ventilation and Air Conditioning) assembly, and the HVAC assembly includes an indoor condenser, an indoor evaporator, a blower and a damper mechanism (not shown in the figure), wherein the damper mechanism can be used to selectively conduct the air duct leading to the indoor condenser and / or the air duct leading to the indoor evaporator. The HVAC in this embodiment is used to be installed in the cab of the vehicle; the outdoor heat exchanger includes a first outdoor heat exchanger (i.e. Figure 3 、 Figure 4 Heat exchanger 1 in the outdoor heat exchanger) and the second outdoor heat exchanger (i.e. Figure 3 、 Figure 4 In heat exchanger 1), the motor radiator is positioned between the two outdoor heat exchangers. When the cooling fans for the first outdoor heat exchanger, the motor radiator, and the second outdoor heat exchanger are activated, the air flows from the first outdoor heat exchanger to the motor radiator, and then from the motor radiator to the second outdoor heat exchanger. The motor radiator, first outdoor heat exchanger, and second outdoor heat exchanger are integrated, allowing the first and second outdoor heat exchangers to share the motor radiator's cooling fan. This not only saves space on the vehicle but also reduces costs.

[0021] If one outdoor heat exchanger is used, for example, if only the first outdoor heat exchanger (i.e. Figure 3 、 Figure 4 Heat exchanger 1 in the figure), then when heating in winter, the first outdoor heat exchanger is the evaporator, and it is easy for the first outdoor heat exchanger to frost. The unit needs to defrost, which affects the heating effect and ultimately affects the comfort. If only the second outdoor heat exchanger (i.e. Figure 3 、 Figure 4 If the heat exchanger 2 is used, then during summer cooling, because the second outdoor heat exchanger is placed behind the motor radiator, the wind will first pass through the motor radiator and then the second outdoor heat exchanger. This will result in a high inlet temperature for the second outdoor heat exchanger, which will not only affect the cooling effect but also the reliability of the product. Therefore, the present invention uses two outdoor heat exchangers to solve the above problems.

[0022] The compressor outlet is connected to the inlet of the indoor condenser, which is connected to the inlet of the second outdoor heat exchanger via a pipeline. The outlet of the second outdoor heat exchanger is connected to the inlet of the compressor via a gas-liquid separator, forming a heating cycle. The compressor outlet is also connected to the inlet of the first outdoor heat exchanger, which is connected to the inlet of the evaporator via a pipeline. The outlet of the evaporator returns to the inlet of the compressor via the gas-liquid separator, forming a refrigeration cycle. To achieve cooling and heating control, the present invention further provides corresponding valves in the heating cycle and the refrigeration cycle. In this embodiment, a first solenoid valve is provided in the pipeline between the inlet of the second outdoor heat exchanger and the outlet of the indoor condenser in the heating cycle, and a second solenoid valve is provided in the pipeline between the inlet of the evaporator and the outlet of the first outdoor heat exchanger in the refrigeration cycle. Because the compressor outlet must be connected to both the inlet of the first outdoor heat exchanger and the inlet of the indoor condenser, the present invention utilizes a three-way valve for ease of connection. Specifically, the first port of the three-way valve is connected to the compressor outlet, the second port is connected to the inlet of the first outdoor heat exchanger, and the third port is connected to the inlet of the indoor condenser. In order to facilitate the adjustment of the opening of the electronic expansion valve, the utility model also sets P / T (pressure / temperature sensor) at the outlet of the compressor, the inlet of the first outdoor heat exchanger and the outlet of the evaporator. By detecting the pressure and temperature, the superheat at the outlet of the evaporator can be calculated to adjust the opening of the electronic expansion valve, thereby achieving energy saving and reliable operation of the system.

[0023] The working principle of the heat pump air conditioning system is as follows:

[0024] When there is a cooling demand, such as Figure 4As shown, the first solenoid valve is controlled to be disconnected and the second solenoid valve is connected. The compressor inputs the compressed high-temperature and high-pressure refrigerant gas into the first outdoor heat exchanger through the three-way valve. At this time, the first outdoor heat exchanger is in condenser mode, and the heat dissipation fan on the motor radiator is used to dissipate heat to the first outdoor heat exchanger, so that the refrigerant passing through the first outdoor heat exchanger is cooled. The cooled refrigerant enters the evaporator under the control of the second solenoid valve and the electronic expansion valve. The low-temperature refrigerant exchanges heat with the indoor environment in the evaporator to achieve the purpose of lowering the ambient temperature of the cab. After that, the refrigerant gas passes through the gas-liquid separator (referred to as gas separator) and returns to the input end of the compressor for compression processing by the compressor, thereby realizing the circulation of the cooling gas.

[0025] When there is a demand for heating, such as Figure 3 As shown, the second solenoid valve is controlled to be disconnected and the first solenoid valve is connected. The compressor inputs the compressed high-temperature and high-pressure refrigerant gas into the indoor condenser through the three-way valve. At this time, the indoor condenser exchanges heat with the cab environment, so that the ambient temperature in the cab increases. Due to the heat exchange, the refrigerant output from the indoor condenser is cooled into liquid. The refrigerant liquid enters the second outdoor heat exchanger under the control of the first solenoid valve and the electronic expansion valve, and the cooling fan is started. Under the action of the cooling fan, the heat of the motor will be transferred to the second outdoor heat exchanger, thereby increasing the temperature of the second outdoor heat exchanger, so that the second outdoor heat exchanger can evaporate and absorb heat better. The refrigerant passing through the second outdoor heat exchanger passes through the gas-liquid separator (referred to as gas separator) and returns to the input end of the compressor for compression processing by the compressor, thereby realizing the circulation of the cooling gas.

[0026] Through the above process, it can be seen that the utility model can fully utilize the waste heat of the motor to heat the second outdoor heat exchanger, effectively solving the problem of frost during heat pump heating. In addition, the motor radiator of the utility model is arranged between the first outdoor heat exchanger and the second outdoor heat exchanger. In cooling mode, the motor radiator fan is turned on, and the wind first passes through the first outdoor heat exchanger and then passes through the motor radiator to dissipate heat to the external environment. This arrangement prevents the heat of the motor radiator from being reversely transferred to the first outdoor heat exchanger, ensuring the heat dissipation effect of the first outdoor heat exchanger; while in heating mode, the motor radiator fan is turned on, and the wind first passes through the motor radiator and then passes through the second outdoor heat exchanger. The waste heat of the motor can be fully and effectively used to heat the second outdoor heat exchanger, avoiding frost on the second outdoor heat exchanger.

Claims

1. A heat pump air conditioning system, comprising a compressor, an indoor heat exchanger and an outdoor heat exchanger, characterized in that: It also includes a motor radiator. The outdoor heat exchanger includes a first outdoor heat exchanger and a second outdoor heat exchanger. The indoor heat exchanger includes an evaporator and an indoor condenser. The outlet of the compressor, the first outdoor heat exchanger, the evaporator and the inlet of the compressor are connected in sequence to form a refrigeration cycle loop; the outlet of the compressor, the indoor condenser, the second outdoor heat exchanger and the inlet of the compressor are connected in sequence to form a heating cycle loop. The motor radiator is used to transfer the heat of the motor to the second outdoor heat exchanger.

2. The heat pump air conditioning system according to claim 1, characterized in that: The motor radiator is arranged between the first outdoor heat exchanger and the second outdoor heat exchanger.

3. The heat pump air conditioning system according to claim 1 or 2, characterized in that: The motor radiator, the first outdoor heat exchanger and the second outdoor heat exchanger are integrated.

4. The heat pump air conditioning system according to claim 3, characterized in that: The first outdoor heat exchanger and the second outdoor heat exchanger share a cooling fan, and the wind direction of the cooling fans used by the first outdoor heat exchanger, the motor radiator and the second outdoor heat exchanger when started is: from the first outdoor heat exchanger to the motor radiator, and then from the motor radiator to the second outdoor heat exchanger.

5. The heat pump air conditioning system according to claim 1 or 2, characterized in that: The heating cycle is provided with a first switch valve for controlling the conduction of the heating cycle when there is a heating demand; the cooling cycle is provided with a second switch valve for controlling the conduction of the cooling cycle when there is a cooling demand.

6. The heat pump air conditioning system according to claim 5, characterized in that: The heating cycle and the refrigeration cycle are both provided with electronic expansion valves.

7. The heat pump air conditioning system according to claim 6, characterized in that: The compressor outlet and the evaporator outlet in the heating cycle are both provided with temperature sensors and pressure sensors.

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