Ejector heat pump system of coupling air supply enthalpy increasing technology

Abstract

The utility model discloses an ejector heat pump system of a coupling air supply enthalpy increasing technology, and belongs to the field of heat pumps. The system comprises a compressor, a condenser, an ejector, a flash tank, an evaporator and a gas-liquid separator, an outlet of the compressor is connected with an inlet of the condenser, an outlet of the condenser is connected with a working fluid inlet of the ejector through a first needle valve, and a secondary fluid inlet of the ejector is connected with an outlet of the gas-liquid separator through a second needle valve. The outlet is connected with an inlet of the flash tank, the inlet of the flash tank is further connected with an outlet of the condenser through a third needle valve and a first throttling valve, a gas outlet of the flash tank is connected with a middle air supplement and suction port of the compressor through a fourth needle valve, and a liquid outlet of the flash tank is connected with an inlet of the evaporator through a second throttling valve; the inlet of the evaporator is further connected with an outlet of the condenser through a fifth needle valve and a first throttling valve, an outlet of the evaporator is connected with an inlet of the gas-liquid separator, and an outlet of the gas-liquid separator is connected with an air suction port of the compressor through a sixth needle valve.

Description

TECHNICAL FIELD

[0001] The utility model belongs to electric automobile heat pump technical field, concretely relates to a kind of ejector heat pump system of coupling air supplementing enthalpy increasing technology. BACKGROUND

[0002] According to the research of American Automobile Industry Association (SAE), the energy consumption of air conditioning refrigeration and PTC material heating accounts for 33% of the whole vehicle energy consumption. At the same time, the pure electric vehicle has serious power battery attenuation in winter and its cruising range will reduce nearly 50% when it runs at full load under the condition of heating PTC material. As a kind of efficient, energy-saving and environment-friendly heating technology, the heat pump can convert low-grade heat energy into high-grade heat energy while consuming a small amount of electric energy. The heat pump technology can effectively reduce the energy consumption of electric vehicle and increase its cruising range when it is used for winter heating of electric vehicle. However, under the condition of low temperature in winter, the decrease of outdoor temperature will cause the decrease of evaporation temperature (pressure), resulting in the decrease of refrigerant circulation flow and the decrease of heating capacity. The decrease of evaporation pressure will further cause the increase of system compression ratio and the increase of exhaust temperature, which reduces the reliability and safety of compressor operation and seriously hinders the popularization and application of heat pump system.

[0003] The air supplementing enthalpy increasing technology can improve the heating energy efficiency performance of heat pump system under low ambient temperature condition. The typical air supplementing enthalpy increasing heat pump system mainly consists of one intermediate air supplementing compressor, evaporator, condenser, flash tank and multiple throttling components. The technology adopts two-stage throttling and intermediate air supplementing cooling method to reduce the enthalpy value of refrigerant at the inlet of evaporator, increase the heat absorption amount of refrigerant in evaporator, and additionally provide air supplementing branch to increase the refrigerant flow in condenser. However, under lower ambient temperature, when the pressure in flash tank is lower than the air supplementing pressure, air supplementing backflow problem is easy to occur, which affects the normal operation of system and reduces the overall heating performance. In addition, multiple throttling processes in air supplementing enthalpy increasing technology will cause a large amount of expansion work loss and reduce the performance of system.

[0004] The ejector technology can realize the recovery of part of expansion work, reduce the irreversible loss of throttling process in throttling type expansion mechanism, and further significantly improve the efficiency of heat pump drying system. The technology can be used for improving the performance of heat pump under low temperature environment, but the structure of ejector is fixed and can only improve the heating performance of system when it operates near the design condition. When the operating condition deviates from the design condition of ejector, the performance of system will be reduced. UTILITY MODEL CONTENTS

[0005] In order to solve the problems in the prior art, the utility model provides a kind of ejector heat pump system of coupling air supplementing enthalpy increasing technology.

[0006] The technical scheme of the utility model is as follows:

[0007] The utility model discloses a kind of ejector heat pump systems of coupling air supplementing enthalpy-increasing technology, the system includes compressor, condenser, ejector, flash tank, evaporator and gas-liquid separator;

[0008] The outlet of the compressor is connected with the inlet of the condenser, the outlet of the condenser is connected with the working fluid inlet of the ejector through a first needle valve, the secondary fluid inlet of the ejector is connected with the outlet of the gas-liquid separator through a second needle valve, the outlet of the ejector is connected with the inlet of the flash tank, the inlet of the flash tank is also connected with the outlet of the condenser through a third needle valve and a first throttling valve, the gas outlet of the flash tank is connected with the middle suction port of the compressor through a fourth needle valve, the liquid outlet of the flash tank is connected with the inlet of the evaporator through a second throttling valve, the inlet of the evaporator is also connected with the outlet of the condenser through a fifth needle valve and a first throttling valve, the outlet of the evaporator is connected with the inlet of the gas-liquid separator, and the outlet of the gas-liquid separator is connected with the suction port of the compressor through a sixth needle valve.

[0009] Compared with the prior art, the utility model has the beneficial effects that:

[0010] The utility model broadens the operation range of the heat pump system, and ensures that the heat pump system can operate efficiently in low-temperature and ultra-low-temperature environments. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a structure schematic view of the ejector heat pump system of coupling air supplementing enthalpy-increasing technology of the utility model embodiment.

[0012] REFERENCE SIGNS

[0013] 1-compressor; 2-condenser; 3-ejector; 4-flash tank; 5-evaporator; 6-gas-liquid separator; V1-first throttling valve; V2-second throttling valve; V3-V8-needle valve. DETAILED DESCRIPTION

[0014] The utility model will be further described and explained in combination with specific implementation manners. The embodiment is only a demonstration of the disclosure and does not define the limit range. The technical features of each embodiment in the utility model can be combined correspondingly without mutual conflict.

[0015] As Figure 1 shown, it shows the composition of the ejector heat pump system of coupling air supplementing enthalpy-increasing technology of the utility model, and the ejector heat pump system of coupling air supplementing enthalpy-increasing technology includes compressor 1, condenser 2, ejector 3, flash tank 4, evaporator 5, gas-liquid separator 6, first throttling valve V1, second throttling valve V2 and six needle valves V3-V8.

[0016] The outlet of the compressor 1 is connected with the inlet of the condenser 2, the outlet of the condenser 2 is connected with the working fluid inlet of the ejector 3 through a needle valve V3, the secondary flow fluid inlet of the ejector 3 is connected with the outlet of the gas-liquid separator 6 through a needle valve V7, the outlet of the ejector 3 is connected with the inlet of the flash tank 4, the inlet of the flash tank 4 is also connected with the outlet of the condenser 2 through a needle valve V4 and a first throttling valve V1, the gas outlet of the flash tank 4 is connected with the intermediate suction port of the compressor 1 through a needle valve V8, the liquid outlet of the flash tank 4 is connected with the inlet of the evaporator 5 through a second throttling valve V2, the inlet of the evaporator 5 is also connected with the outlet of the condenser 2 through a needle valve V5 and the first throttling valve V1, the outlet of the evaporator 5 is connected with the inlet of the gas-liquid separator 6, and the outlet of the gas-liquid separator 6 is connected with the suction port of the compressor 1 through a needle valve V6, wherein the needle valve V6 is in a normally open state, and the rest of the needle valves and the first throttling valve V1 and the second throttling valve V2 can adjust the opening degree thereof.

[0017] In the embodiment, the compressor is used for outputting refrigerant, the refrigerant is CO2 or R134a, and the intermediate suction port is arranged in the compressor and on a flow channel in the compressor and along a direction from a suction port to an outlet of the compressor.

[0018] In a preferred embodiment, the outlet of the condenser is connected with the first needle valve and the first throttling valve through a three-way pipe fitting; the first throttling valve is connected with the third needle valve and the fifth needle valve through a three-way pipe fitting; and the outlet of the gas-liquid separator is connected with the third needle valve and the sixth needle valve through a three-way pipe fitting.

[0019] The inner cavity of the ejector comprises a nozzle, a mixing chamber and a diffuser chamber which are sequentially communicated, the working fluid inlet is arranged at the inlet of the nozzle, the outlet of the nozzle is connected with the inlet of the mixing chamber, the outlet of the mixing chamber is connected with the inlet of the diffuser chamber, the outlet of the diffuser chamber is the outlet of the ejector, and the secondary flow fluid inlet is communicated with the mixing chamber.

[0020] The gas-liquid separator further has a liquid phase discharge outlet for discharging the liquid phase refrigerant separated from the refrigerant, so as to ensure the purity of the gas phase refrigerant and avoid the liquid refrigerant entering the compressor.

[0021] In a specific embodiment, the air injection and enthalpy increasing heat pump system has an ejector heating mode, an air injection and enthalpy increasing heating mode and a common heating mode. The ejector heating mode is used for heating in an ultra-low environment (below-20 DEG C), at this time, the heat pump system operates in the vicinity of the design condition of the ejector, the ejector 3 can effectively recover the expansion work of the high-pressure refrigerant output by the condenser 2, reduce the loss of the heat pump system, and thus improve the heating performance of the heat pump system at an ultra-low temperature.

[0022] When the system works in the ejector heating mode and the real-time substream and main stream mass flow ratio is equal to the preset substream and main stream mass flow ratio, the first throttling valve V1 is kept fully closed, at which time the flow of the main stream fluid of the ejector 3 is maximum, and the recovered expansion work is maximum; when the system works in the ejector heating mode and the real-time substream and main stream mass flow ratio is not equal to the preset substream and main stream mass flow ratio, the flow of the main stream fluid and the substream fluid of the ejector is controlled by adjusting the first throttling valve V1 and the needle valve V7 and the needle valve V6, so as to ensure that the ejector normally operates.

[0023] In a preferred embodiment of the present application, when the heat pump system works in the ejector heating mode and the real-time substream and main stream mass flow ratio is equal to the preset substream and main stream mass flow ratio, the flow path working process of the refrigerant is as follows: the compressor 1 outputs high-temperature refrigerant to the condenser 2, the condenser 2 performs heat release on the high-temperature refrigerant and outputs high-pressure refrigerant, the high-pressure refrigerant enters the ejector 3 from the working fluid inlet of the ejector 3 as the main stream fluid after the flow control of the needle valve V3, the ejector 3 outputs gas-liquid two-phase refrigerant to the flash tank 4, the gas refrigerant output by the flash tank 4 enters the compressor 1 after the flow control of the needle valve V8, and the output liquid refrigerant enters the evaporator 5 after the throttling of the second throttling valve V2; the evaporator 5 outputs evaporated refrigerant to the gas-liquid separator 6, the gas-liquid separator 6 outputs gas refrigerant, part of the gas refrigerant enters the ejector 3 from the substream fluid inlet of the ejector 3 as the substream fluid, the substream fluid and the main stream fluid are mixed to form medium-pressure gas-liquid two-phase refrigerant, and finally the gas-liquid two-phase refrigerant reenters the flash tank 4; the remaining gas refrigerant output by the gas-liquid separator 6 enters the compressor 1 to complete the cycle after the flow control of the needle valve V6.

[0024] In the preferred embodiment of the utility model, when the heat pump system works in the ejector heating mode and the real-time secondary flow and primary flow mass flow ratio is not equal to the preset secondary flow and primary flow mass flow ratio, the flow path working process of the refrigerant is: the compressor 1 outputs high-temperature refrigerant to the condenser 2, the condenser 2 releases heat to the high-temperature refrigerant and outputs gas-liquid two-phase refrigerant, part of the gas-liquid two-phase refrigerant enters the ejector 3 from the working fluid inlet of the ejector 3 after the flow control of the needle valve V3, the remaining part of the gas-liquid two-phase refrigerant enters the evaporator 5 after the throttling of the first throttling valve V1 and the flow control of the needle valve V5, the evaporator 5 outputs evaporated refrigerant to the gas-liquid separator 6, the gas-liquid separator 6 outputs gas refrigerant, part of the gas refrigerant enters the ejector 3 from the secondary flow fluid inlet of the ejector 3, the secondary flow fluid mixes with the high-speed working fluid passing through the nozzle in the ejector to form high-speed fluid, then the high-speed fluid passes through the diffuser section at the end of the ejector to reduce the flow rate and increase the static pressure, and finally the gas-liquid two-phase refrigerant is formed, and finally the gas-liquid two-phase refrigerant enters the flash tank 4, the flash tank 4 outputs gas refrigerant to the compressor 1, the flash tank 4 also outputs liquid refrigerant, and the liquid refrigerant enters the evaporator 5 after the throttling of the second throttling valve V2; the remaining gas refrigerant output by the gas-liquid separator 6 enters the compressor 1 to complete the cycle after the flow control of the needle valve V6.

[0025] In the ejector heating mode, the function of the ejector 3 is to recover part of the expansion work of the high-pressure refrigerant at the outlet of the condenser 2, reduce the heat loss of the heat pump system and improve the heating performance, and the function of the first throttling valve V1 is to adjust the primary flow entering the ejector 3 to ensure the normal operation of the ejector 3. When the operating conditions of the heat pump system are close to the design conditions of the ejector 3, the first throttling valve V1 is kept closed, at this time, the primary flow of the ejector 3 is maximum, and the recovered expansion work is maximum; when the operating conditions of the heat pump system deviate from the design conditions of the ejector, the primary flow and the secondary flow of the ejector 3 can be controlled by adjusting the first throttling valve V1 and the needle valves V6-V7 at the outlet of the gas-liquid separator 6, so as to ensure the normal operation of the ejector 3.

[0026] The air supplementing and enthalpy increasing heating mode is used for heating in a low-temperature environment (-20-0 DEG C), which deviates far from the design conditions of the ejector, and the use of the ejector will reduce the performance of the heat pump system, so the air supplementing and enthalpy increasing technology is adopted. The air supplementing and enthalpy increasing technology reduces the enthalpy of the refrigerant at the inlet of the evaporator 5, increases the heat absorption amount of the refrigerant in the evaporator 5, and additionally provides an air supplementing branch to improve the refrigerant flow in the condenser 2, so as to improve the heating performance of the heat pump system, and the air supplementing pressure in this temperature range is lower than the pressure in the flash tank 4, so there is no air supplementing backflow problem.

[0027] In the above-mentioned heating mode of the gas supplement and enthalpy increasing, the needle valve V3 from the condenser 2 to the ejector 3 is closed, the high-temperature refrigerant at the outlet of the compressor 1 is discharged through the condenser 2 to release heat, and then all the refrigerant is expanded through the first throttling valve V1. At this time, the needle valve V5 between the first throttling valve V1 and the evaporator 5 is closed, the expanded refrigerant enters the flash tank 4 to be separated, the separated gas refrigerant enters the compressor 1 from the gas supplement branch of the compressor, the liquid refrigerant is throttled again through the second throttling valve V2 and then enters the evaporator 5 to release heat, the evaporated refrigerant enters the gas-liquid separator 6, and the separated gas refrigerant enters the compressor 1 to complete the cycle. In the heating mode of the gas supplement and enthalpy increasing, the heat pump system follows the coupling control principle, that is, the adjustment of any throttling valve will affect the refrigerant flow in the evaporator 5 and the intermediate gas supplement of the compressor, so the joint control is required between the throttling valves and the needle valves.

[0028] In an embodiment of the utility model, when the heat pump system works in the heating mode of the gas supplement and enthalpy increasing, the working process of the refrigerant flow path is as follows: the compressor 1 outputs high-temperature refrigerant to the condenser 2, the condenser 2 releases heat from the high-temperature refrigerant and outputs gas-liquid two-phase refrigerant, the gas-liquid two-phase refrigerant enters the flash tank 4 after throttling through the first throttling valve V1 and flow control through the needle valve V4, the gas refrigerant output from the flash tank 4 enters the compressor 1 after flow control through the needle valve V8, the liquid refrigerant is throttled through the second throttling valve V2 and then enters the evaporator 5, the evaporator 5 outputs the evaporated refrigerant to the gas-liquid separator 6, the gas-liquid separator 6 outputs the gas refrigerant, and the gas refrigerant enters the compressor 1 to complete the cycle after flow control through the needle valve V6.

[0029] The ordinary heating mode is used in the normal temperature (above 0℃) condition, at this time, the improvement effect of the gas supplement and enthalpy increasing technology is continuously reduced with the increase of the evaporation temperature of the heat pump system, and the control difficulty of the heat pump system is increased due to the use of multiple throttling processes, so the use of the flash tank 4 is cancelled, and only one throttling process is used to reduce the control difficulty of the heat pump system.

[0030] In the above-mentioned ordinary heating mode, the needle valve V3 from the condenser 2 to the ejector 3 is closed, the high-temperature refrigerant at the outlet of the compressor 1 is discharged through the condenser 2 to release heat, and then all the refrigerant is expanded through the first throttling valve V1. At this time, the needle valve V4 between the first throttling valve V1 and the flash tank 4 is closed, the expanded refrigerant enters the evaporator 5 to release heat, and then enters the gas-liquid separator 6. The needle valve V7 between the gas-liquid separator 6 and the ejector 3 is closed, and the gas refrigerant separated from the gas-liquid separator 6 enters the compressor 1 to complete the cycle.

[0031] In the utility model a concrete embodiment, when the heat pump system works in the air supplementing and enthalpy increasing heating mode, the flow path working process of refrigerant is: the compressor 1 outputs high temperature refrigerant to the condenser 2, the condenser 2 carries out heat release to high temperature refrigerant and outputs gas-liquid two-phase refrigerant, the gas-liquid two-phase refrigerant enters the evaporator 5 after throttling of the first throttling valve V1 and flow control of the needle valve V5, the evaporator 5 outputs evaporated refrigerant to the gas-liquid separator 6, the gas-liquid separator 6 outputs gas refrigerant, the gas refrigerant enters the compressor 1 after flow control of the needle valve V6 to complete circulation.

[0032] The ordinary heating mode is used in the case that ambient temperature is not low, at this time, the working condition of the heat pump system is far away from the design condition of the ejector, the ejector 3 cannot normally operate, in addition, the promotion effect of air supplementing and enthalpy increasing is continuously reduced with the increase of the evaporation temperature of the heat pump system, which instead promotes the control complexity of the heat pump system. Therefore, the ordinary heating mode is adopted to simplify the system control process, and the operating state of the heat pump system is controlled by controlling the opening degree of the first throttling valve V1 and the rotating speed of the compressor 1.

[0033] In the utility model a concrete embodiment, the heating mode switching method of the heat pump system comprises the following steps:

[0034] The external temperature sensor acquires the ambient temperature in real time, and according to the ambient temperature, the opening and closing of all needle valves and throttling valves are controlled to switch the system among the ejector heating mode, the air supplementing and enthalpy increasing heating mode and the ordinary heating mode;

[0035] If the ambient temperature is-20 DEG C and below, the third needle valve is closed, the remaining needle valves and the second throttling valve are opened, and the opening and closing of the first throttling valve is controlled according to the real-time secondary flow and primary flow mass flow ratio, at this time, the system works in the ejector heating mode, which makes the system maintain high heating performance in the super-low temperature environment and does not appear the case of compressor intermediate air supplementing backflow; when the real-time secondary flow and primary flow mass flow ratio is not equal to the preset secondary flow and primary flow mass flow ratio, the first throttling valve is opened, and when the real-time secondary flow and primary flow mass flow ratio is equal to the preset secondary flow and primary flow mass flow ratio, the first throttling valve is closed;

[0036] If the ambient temperature is-20 DEG C to 0 DEG C, the first needle valve, the second needle valve and the fifth needle valve are closed, the remaining needle valves and the throttling valves are opened, at this time, the system works in the air supplementing and enthalpy increasing heating mode, which makes the system have high heating performance in the low temperature environment and can avoid the operating failure of the ejector under the condition far away from the design condition;

[0037] If the ambient temperature is greater than 0 DEG C, the first needle valve, the second needle valve, the third needle valve, the fourth needle valve and the second throttle valve are closed, and the remaining needle valves and the first throttle valve are opened, at this time, the system works in the ordinary heating mode, at this time, the ambient temperature, the system control is more simple, the ordinary heating mode is adopted.

[0038] The heat pump system combines the ejector technology and the air supplement and enthalpy increasing technology, so that the system can be switched and operated in the ejector heating mode and the air supplement and enthalpy increasing heating mode.

[0039] The above-mentioned embodiments only express several implementation manners of the heat pump system, the description is more specific and detailed, but it cannot be understood as the limitation of the patent range of the heat pump system. For the ordinary skilled in the art, without departing from the concept of the heat pump system, a plurality of deformations and improvements can be made, which belong to the protection range of the heat pump system.

Claims

1. A jet heat pump system coupled with gas injection and enthalpy enhancement technology, characterized in that, The system comprises a compressor, a condenser, an ejector, a flash tank, an evaporator and a gas-liquid separator; The outlet of the compressor is connected with the inlet of the condenser, the outlet of the condenser is connected with the working fluid inlet of the ejector through a first needle valve, the secondary fluid inlet of the ejector is connected with the outlet of the gas-liquid separator through a second needle valve, the outlet of the ejector is connected with the inlet of the flash tank, the inlet of the flash tank is also connected with the outlet of the condenser through a third needle valve and a first throttle valve, the gas outlet of the flash tank is connected with the intermediate suction port of the compressor through a fourth needle valve, the liquid outlet of the flash tank is connected with the inlet of the evaporator through a second throttle valve, the inlet of the evaporator is also connected with the outlet of the condenser through a fifth needle valve and the first throttle valve, the outlet of the evaporator is connected with the inlet of the gas-liquid separator, and the outlet of the gas-liquid separator is connected with the suction port of the compressor through a sixth needle valve.

2. The coupled ejector heat boost technology ejector heat pump system of claim 1, wherein, The compressor is used for outputting refrigerant, and the refrigerant is CO2 or R134a.

3. The coupled ejector heat boost technology ejector heat pump system of claim 1, wherein, The intermediate suction port is arranged in the compressor and along the flow channel of the compressor from the suction port to the outlet.

4. The coupled ejector heat boost technology ejector heat pump system of claim 1, wherein, The sixth needle valve is in a normally open state, and the remaining needle valves and the first and second throttle valves can adjust their opening degrees.

5. The coupled ejector heat boost technology ejector heat pump system of claim 1, wherein, The outlet of the condenser is connected with the first needle valve and the first throttle valve through a three-way pipe fitting; the first throttle valve is connected with the third needle valve and the fifth needle valve through a three-way pipe fitting; and the outlet of the gas-liquid separator is connected with the third needle valve and the sixth needle valve through a three-way pipe fitting.

6. The coupled ejector heat boost technology ejector heat pump system of claim 1, wherein, The inner cavity of the ejector comprises a nozzle, a mixing chamber and a diffuser chamber which are connected in sequence, the working fluid inlet is arranged at the inlet of the nozzle, the outlet of the nozzle is connected with the inlet of the mixing chamber, the outlet of the mixing chamber and the inlet of the diffuser chamber are connected, the outlet of the diffuser chamber is the outlet of the ejector, and the secondary fluid inlet is connected with the mixing chamber.

7. The coupled ejector heat boost technology ejector heat pump system of claim 2, wherein, The gas-liquid separator also has a liquid phase discharge outlet for discharging the liquid phase refrigerant separated from the refrigerant, ensuring the purity of the gas phase refrigerant and avoiding the liquid refrigerant entering the compressor.

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