Air-supplementing enthalpy-increasing heat pump system

Abstract

The utility model discloses an air-supplementing enthalpy-increasing heat pump system which comprises a compressor, a first indoor heat exchanger, a flash tank with a subcooler, a second indoor heat exchanger, an outdoor heat exchanger, a gas-liquid separator, a plurality of throttling valves and a needle valve. According to the system, a flash tank with a subcooler is adopted, a subcooler air supplementing system and a flash tank air supplementing system are coupled, the system can be switched among a subcooler air supplementing mode, a flash tank air supplementing mode and a parallel dehumidification heating mode through adjustment of a throttling valve and a needle valve, and supplemented air backflow is prevented under the condition that the heat exchange efficiency is guaranteed. And meanwhile, the indoor evaporator and the outdoor evaporator are connected in parallel, so that the evaporation pressure in the two evaporators can be independently controlled, and frosting of the indoor evaporator is effectively prevented while the dehumidification capacity of the indoor evaporator is improved.

Description

TECHNICAL FIELD

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

[0002] According to the research of American Automobile Industry Association (SAE), the energy consumption of air conditioning refrigeration and PTC (Positive Temperature Coefficient) material heating accounts for 33% of the whole vehicle energy consumption. At the same time, the power battery of pure electric vehicle is seriously attenuated in winter, and the full load operation under the condition of heating by heating PTC material will reduce the cruising range by nearly 50%. As an efficient, energy-saving and environmentally 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 used in electric vehicle winter heating can effectively reduce the energy consumption of electric vehicle and increase its cruising range. 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 increase the compression ratio of the system and increase the exhaust temperature, which will reduce the reliability and safety of the compressor operation, and seriously hinder the popularization and application of the heat pump system.

[0003] The air supplementing enthalpy increasing technology can improve the heating energy efficiency performance of the heat pump system under low ambient temperature condition. The application of air supplementing enthalpy increasing technology not only increases the supercooling degree and circulation flow, realizes the purpose of improving the heating capacity, and to some extent, widens the operating temperature range of the system under low ambient temperature, but also reduces the power consumption of the compressor by building a quasi-two-stage compression system, so that the COP (Coefficient of Performance) is significantly improved. The typical air supplementing enthalpy increasing heat pump system mainly consists of one intermediate air supplementing compressor, evaporator, condenser, flash tank or subcooler and multiple throttling components, which is divided into subcooler air supplementing system and flash tank air supplementing system. The subcooler air supplementing system follows the principle of modular independent design, that is, the flow of refrigerant in the evaporator and the intermediate air supplementing flow are controlled by two throttling valves respectively, which is convenient for adjustment, and the air supplementing pressure will not be higher than the exhaust pressure, so that the backflow of refrigerant will not occur, but the system COP will be affected by the heat transfer efficiency of the subcooler. Although the flash tank air supplementing system can avoid the problem of low heat transfer efficiency, the system follows the principle of coupled control, that is, the adjustment of any throttling valve will affect the flow of refrigerant in the evaporator and the intermediate air supplementing amount, which needs to be controlled jointly, and backflow is easy to occur when the pressure in the flash tank is lower than the air supplementing pressure. SUMMARY

[0004] The utility model discloses a purpose at providing a kind of gas supplementing enthalpy increasing heat pump system, the system adopts the flash tank with subcooler, subcooler gas supplementing system and flash tank gas supplementing system coupling, make system can switch in subcooler gas supplementing mode and flash tank gas supplementing mode two modes, prevent gas supplementing backflow under the condition of guaranteeing heat exchange efficiency.Meanwhile system connects in parallel with indoor evaporator and outdoor evaporator, so that the evaporation pressure in two evaporators can be controlled separately, while increasing indoor evaporator dehumidification capacity, effectively prevent its frost.

[0005] The utility model discloses a purpose at providing a kind of gas supplementing enthalpy increasing heat pump system, the system adopts the flash tank with subcooler, subcooler gas supplementing system and flash tank gas supplementing system coupling, make system can switch in subcooler gas supplementing mode and flash tank gas supplementing mode two modes, prevent gas supplementing backflow under the condition of guaranteeing heat exchange efficiency.Meanwhile system connects in parallel with indoor evaporator and outdoor evaporator, so that the evaporation pressure in two evaporators can be controlled separately, while increasing indoor evaporator dehumidification capacity, effectively prevent its frost.

[0006] A kind of gas supplementing enthalpy increasing heat pump system, by compressor, first indoor heat exchanger, the flash tank with subcooler, second indoor heat exchanger, outdoor heat exchanger, gas-liquid separator, several throttling valves and several needle valves are formed.

[0007] The outlet of compressor is connected with the inlet of first indoor heat exchanger, the outlet of first indoor heat exchanger has two branches, wherein, first throttling valve is arranged on the first branch, the first branch is connected with the tank body inlet of the flash tank with subcooler, the second branch is connected with the subcooler inlet of the flash tank with subcooler;The tank body of the flash tank with subcooler has liquid phase outlet and gas phase outlet, wherein the gas phase outlet is connected with the gas supplementing inlet of compressor, the liquid phase outlet is connected with the inlet of outdoor heat exchanger by second throttling valve;The outlet of outdoor heat exchanger is connected with the inlet of gas-liquid separator;

[0008] The outlet of the subcooler of the flash tank with subcooler is connected with third throttling valve, the outlet of third throttling valve is divided into two branches, one branch is connected with the inlet of outdoor heat exchanger, the other branch is connected with the inlet of second indoor heat exchanger, the outlet of second indoor heat exchanger is connected with the inlet of gas-liquid separator by fourth throttling valve;

[0009] The outlet of gas-liquid separator is connected with the inlet of compressor.

[0010] Preferably, first needle valve is arranged on the second branch, second needle valve is arranged on the pipeline between the outlet of third throttling valve and the inlet of outdoor heat exchanger, and third needle valve is arranged on the pipeline between the gas phase outlet and the inlet of compressor.

[0011] In the above system, the opening degree of the first needle valve can be adjusted.

[0012] The working medium used in the above system is refrigerant, and the refrigerant is CO2 or R134a.

[0013] In the system, the second indoor heat exchanger and the outdoor heat exchanger are in parallel connection, the working pressure of the two can be independently controlled, and the frosting problem caused by the too low evaporation pressure of the refrigerant in the second indoor heat exchanger is avoided; in addition, the refrigerant entering the second indoor heat exchanger is supercooled by the supercooler before throttling, the enthalpy difference of the refrigerant at the inlet and outlet of the second indoor heat exchanger is increased, and the dehumidification effect is enhanced.

[0014] The system of the utility model has the advantages that: the system adopts the flash tank with supercooler, the supercooler air supply system and the flash tank air supply system are coupled, the system can be switched in different working modes through the adjustment of the throttle valve and the needle valve, the air supply backflow is prevented under the condition of ensuring the heat exchange efficiency, the indoor evaporator and the outdoor evaporator are connected in parallel, the evaporation pressure in the two evaporators can be independently controlled, the dehumidification capacity of the indoor evaporator is increased, and the frosting is effectively prevented.

[0015] The system can realize the switching of the supercooler air supply mode, the flash tank air supply mode and the parallel connection dehumidification and heating mode through the adjustment of the throttle valve and the needle valve. When the ambient temperature is low, the flash tank air supply and heating mode takes the flash tank as the key component, has strong heat exchange efficiency, can reduce the enthalpy value of the refrigerant at the inlet of the evaporator, increase the heat absorption amount of the refrigerant in the evaporator, and additionally increase the air supply branch, thereby improving the refrigerant flow in the condenser. When the ambient temperature is low, the flash tank and the air supply branch are prone to air supply backflow, at this time, the heating mode is switched to the supercooler air supply and heating mode, and the heating performance of the system under the lower ambient temperature can be ensured. In the parallel connection dehumidification and heating mode, the second indoor heat exchanger and the outdoor heat exchanger are in parallel connection, the pressure in the two can be independently controlled, the frosting problem caused by the too low evaporation pressure of the refrigerant in the second indoor heat exchanger is avoided; in addition, the refrigerant entering the second indoor heat exchanger is supercooled by the supercooler before throttling, the enthalpy difference of the refrigerant at the inlet and outlet of the second indoor heat exchanger is increased, and the dehumidification effect is enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a structure schematic view of the air supply and enthalpy increasing heat pump system of the utility model embodiment.

[0017] MARKS

[0018] 1-compressor;2-first indoor heat exchanger;3-flash tank with supercooler;4-second indoor heat exchanger;5-outdoor heat exchanger;6-gas-liquid separator;V1-first throttle valve;V2-second throttle valve;V3-third throttle valve;V4-fourth throttle valve;V5-first needle valve;V6-second needle valve;V7-third needle valve. DETAILED DESCRIPTION

[0019] The utility model will be further explained in connection with specific embodiment and drawings.

[0020] As Figure 1 shown, a kind of gas supplementing enthalpy heat pump system, by compressor 1, first indoor heat exchanger 2, with supercooler flash tank 3, second indoor heat exchanger 4, outdoor heat exchanger 5, gas-liquid separator 6, throttling valve V1~V4 and needle valve V5~V7 composition.

[0021] The outlet of compressor 1 is connected with the inlet of first indoor heat exchanger 2, the outlet of first indoor heat exchanger 2 has two branches, wherein, first throttling valve V1 is arranged on the first branch, the first branch is connected with the tank body inlet of with supercooler flash tank 3, the second branch is connected with the supercooler inlet of with supercooler flash tank 3, needle valve V5 is arranged on the second branch;The tank body of with supercooler flash tank 3 has liquid phase outlet and gas phase outlet, wherein the gas phase outlet is connected with the gas supplementing inlet of compressor 1 by needle valve V7, the liquid phase outlet is connected with the inlet of outdoor heat exchanger 5 by second throttling valve V2;The outlet of outdoor heat exchanger 5 is connected with the inlet of gas-liquid separator 6;

[0022] The supercooler outlet of with supercooler flash tank 3 is connected with third throttling valve V3, the outlet of third throttling valve V3 is divided into two branches, wherein one branch is connected with the inlet of outdoor heat exchanger 5 by needle valve V6, the other branch is connected with the inlet of second indoor heat exchanger 4, the outlet of second indoor heat exchanger 4 is connected with the inlet of gas-liquid separator 6 by fourth throttling valve V4,

[0023] The outlet of gas-liquid separator 6 is connected with the inlet of compressor 1.

[0024] Further, as Figure 1 shown, first needle valve V5 is arranged on the second branch, second needle valve V6 is arranged on the pipeline between the outlet of third throttling valve and the inlet of outdoor heat exchanger, and third needle valve V7 is arranged on the pipeline between the gas phase outlet and the inlet of compressor.

[0025] The refrigerant working medium in the system can be CO2, R134a and other common refrigerants, and the type of refrigerant is not limited to one.

[0026] The gas supplementing enthalpy heat pump system can be applied to pure electric vehicle thermal management, building indoor heating and other scenes, and is taken as an example for being applied to pure electric vehicle, the system can realize that pure electric vehicle maintains high heating performance in low temperature environment and prevents indoor dehumidification heat exchanger from frosting. The first indoor heat exchanger 2 in the system is the cabin air heater of electric vehicle, the second indoor heat exchanger 4 is the cabin air dehumidification heat exchanger of electric vehicle, and the outdoor heat exchanger 5 is the outdoor evaporator of electric vehicle.

[0027] The gas supplementing enthalpy heat pump system can realize three heating modes of flash tank gas supplementing heating mode, supercooler gas supplementing heating mode and parallel dehumidification heating mode.

[0028] The flash tank gas injection heating mode is used when the pressure in the flash tank is higher than the gas injection pressure (the pressure at the compressor gas injection port). At this time, the flash tank, as a key component, has excellent heat exchange efficiency, which helps to reduce the enthalpy value at the inlet of the evaporator (outdoor heat exchanger) and improve the system heating COP.

[0029] When the outdoor temperature decreases, the system evaporation pressure and the pressure in the flash tank decrease, and the gas injection pressure is likely to be higher than the pressure in the flash tank, causing gas injection backflow. The subcooler gas injection heating mode is used when gas injection backflow occurs. At this time, the flow rate of the refrigerant in the evaporator and the intermediate gas injection flow rate are separately controlled by the third throttling valve V3 and the first throttling valve V1, respectively, which can ensure that the gas injection pressure is not higher than the exhaust pressure, avoiding the problem of gas injection backflow, and the intermediate gas injection reduces the exhaust temperature of the compressor 1, making the compression process closer to an isentropic process and reducing the power consumption of the compressor 1. The parallel dehumidification and heating mode is used when the indoor air humidity is high. In the parallel dehumidification and heating mode, the second indoor heat exchanger 4 and the outdoor heat exchanger 5 operate in parallel, which can freely control the evaporation pressure of the outdoor and indoor evaporators and effectively avoid the problem of evaporator frosting.

[0030] In the flash tank gas injection heating mode described above, the valves V3 to V6 are closed, and the remaining valves are kept open. The components through which the refrigerant flows include the compressor 1, the first indoor heat exchanger 2, the first throttling valve V1, the flash tank with subcooler 3, the second throttling valve V2, the outdoor heat exchanger 5, and the gas-liquid separator 6. High-temperature refrigerant from the outlet of the compressor 1 first enters the first indoor heat exchanger 2, which at this time functions as a condenser to heat air with the refrigerant. Then, the refrigerant expands and reduces pressure after passing through the first throttling valve V1 and enters the tank body of the flash tank with subcooler 3. The flashed gas refrigerant enters the compressor 1 through the gas injection branch, and the liquid refrigerant expands again after passing through the second throttling valve V2 and enters the outdoor heat exchanger 5, which at this time functions as an evaporator to absorb heat from the air to heat the refrigerant. The evaporated refrigerant is separated by the gas-liquid separator 6, and the gas refrigerant is input into the compressor 1 to complete the cycle.

[0031] In the above-mentioned supercooler air supplement heating mode, the second throttle valve V2 and the fourth throttle valve V4 are closed, and the remaining valves are kept open. The components through which the refrigerant flows include the compressor 1, the first indoor heat exchanger 2, the first throttle valve V1, the supercooler flash tank 3, the third throttle valve V3, the outdoor heat exchanger 5, and the gas-liquid separator 6. The high-temperature refrigerant from the outlet of the compressor 1 first enters the first indoor heat exchanger 2 to heat the air. Then, the refrigerant after being cooled is divided into two branches. One branch enters the tank body of the supercooler flash tank 3 through the first throttle valve V1, and the other branch directly enters the supercooler inside the supercooler flash tank 3. The flow of the refrigerant in the supercooler is adjusted by controlling the opening degree of the first needle valve V5 to ensure that the refrigerant in the tank body is completely vaporized. At this time, the low-pressure refrigerant in the tank body absorbs heat from the high-pressure refrigerant in the supercooler and evaporates into gas, which then enters the compressor 1 through the air supplement branch. The refrigerant in the supercooler is cooled and then enters the outdoor evaporator 5 after being expanded by the third throttle valve V3 to absorb heat from the air. The evaporated refrigerant is separated in the gas-liquid separator 6, and the gas refrigerant is input into the compressor 1 to complete the cycle.

[0032] In the above-mentioned parallel dehumidification and heating mode, the second needle valve V6 is closed, and the remaining valves are kept open. The components through which the refrigerant flows include the compressor 1, the first indoor heat exchanger 2, the first throttle valve V1, the supercooler flash tank 3, the second throttle valve V2, the third throttle valve V3, the second indoor heat exchanger 4, the fourth throttle valve V4, the outdoor heat exchanger 5, and the gas-liquid separator 6. The high-temperature refrigerant from the outlet of the compressor 1 first enters the first indoor heat exchanger 2 to heat the air. Then, the refrigerant after being cooled is divided into two branches. One branch enters the tank body of the supercooler flash tank 3 through the first throttle valve V1, and the other branch directly enters the supercooler inside the supercooler flash tank 3. At this time, the opening degree of the first needle valve V5 is smaller than that in the supercooler air supplement heating mode, so the flow of the refrigerant in the supercooler is relatively low, and the refrigerant in the tank body of the supercooler flash tank 3 is not completely vaporized. After absorbing heat, the refrigerant in the tank body is divided into gas refrigerant and liquid refrigerant. The gas refrigerant enters the compressor 1 through the air supplement branch, and the liquid refrigerant enters the outdoor heat exchanger 5 after passing through the second throttle valve V2 to evaporate, and then enters the gas-liquid separator 6 to separate. The refrigerant in the supercooler is cooled and then enters the second indoor heat exchanger 4 after being expanded by the third throttle valve V3. At this time, the second indoor heat exchanger 4 acts as an evaporator to cool the air and condense the water vapor in the air. The refrigerant from the second indoor heat exchanger 4 then enters the gas-liquid separator 6 through the fourth throttle valve V4 to separate. The separated gas enters the compressor 1 to complete the cycle.

[0033] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A gas-injection enthalpy augmentation heat pump system, characterized by, The system comprises a compressor, a first indoor heat exchanger, a flash tank with a subcooler, a second indoor heat exchanger, an outdoor heat exchanger and a gas-liquid separator. The outlet of the compressor is connected to the inlet of the first indoor heat exchanger, the outlet of the first indoor heat exchanger has two branches, the first branch is provided with a first throttling valve, the first branch is connected to the tank inlet of the flash tank with a subcooler, and the second branch is connected to the subcooler inlet of the flash tank with a subcooler; the tank of the flash tank with a subcooler has a liquid phase outlet and a gas phase outlet, the gas phase outlet is connected to the inlet of the compressor, and the liquid phase outlet is connected to the inlet of the outdoor heat exchanger through a second throttling valve; the outlet of the outdoor heat exchanger is connected to the inlet of the gas-liquid separator; The outlet of the subcooler of the flash tank with a subcooler is connected to a third throttling valve, the outlet of the third throttling valve is divided into two branches, one branch is connected to the inlet of the outdoor heat exchanger, and the other branch is connected to the inlet of the second indoor heat exchanger; the outlet of the second indoor heat exchanger is connected to the inlet of the gas-liquid separator through a fourth throttling valve; The outlet of the gas-liquid separator is connected to the inlet of the compressor.

2. The regasified enhanced heat pump system of claim 1, wherein, A first needle valve is arranged on the second branch, a second needle valve is arranged on the pipeline between the outlet of the third throttling valve and the inlet of the outdoor heat exchanger, and a third needle valve is arranged on the pipeline between the gas phase outlet and the inlet of the compressor.

3. The regasified enhanced heat pump system of claim 1 wherein, The working medium used in the system is a refrigerant, and the refrigerant is CO2 or R134a.

4. The regasified enhanced heat pump system of claim 1 wherein, The second indoor heat exchanger and the outdoor heat exchanger are in parallel connection, and the working pressures of the two can be independently controlled.

5. The regasified enhanced heat pump system of claim 2, wherein, The opening degree of the first needle valve can be adjusted.

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