Intermediate air supply heat pump system

Abstract

The utility model discloses an intermediate air supply heat pump system and relates to the technical field of heat pump systems, a working medium inlet of a first ejector is communicated with a condenser, a working medium outlet of the first ejector is communicated with a first gas-liquid separator, a mixing chamber is arranged between a low-pressure compressor and a high-pressure compressor, and a gas outlet of the first gas-liquid separator is communicated with the mixing chamber. The liquid outlet is communicated with the first expansion valve, the first expansion valve is communicated with the second gas-liquid separator, the gas outlet of the second gas-liquid separator is communicated with the injection inlet of the first injector, the liquid outlet is communicated with the working medium inlet of the evaporator, and the evaporator is communicated with the low-pressure compressor; the compression ratio, the steam exhaust superheat degree and the system input power of the compressor are reduced through two-stage compression, the use stability of the compressor is guaranteed, meanwhile, the double gas-liquid separators are utilized, more saturated refrigerant steam with high pressure and energy directly enters the mixing chamber, and the overall system performance is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of heat pump systems, in particular to an intermediate gas-injected heat pump system. Background Art

[0002] The improvement of the energy efficiency of heat pump systems has always been a research hotspot. The compression ratio of traditional single-stage compression heat pump systems is relatively large, the exhaust temperature of the compressor is relatively high, and the energy efficiency of the system is relatively low.

[0003] At low ambient temperatures, due to the decrease in evaporation pressure, the coefficient of performance (COP) and heat output decrease rapidly as the compression ratio increases. In addition, a high compression ratio will cause the exhaust temperature of the compressor to be too high. If the temperature exceeds the set value, the compressor may shut down due to overheat protection.

[0004] Moreover, an expansion valve is mostly used in heat pumps as a component connecting the condenser and the evaporator to decompress the working medium. However, when all the working medium flows through the expansion valve, the energy loss is relatively large, which in turn leads to a decrease in the performance of the system.

[0005] Therefore, there is an urgent need for an intermediate gas-injected heat pump system with high performance and high stability in the use of the compressor. Summary of the Invention

[0006] The purpose of the utility model is to provide an intermediate gas-injected heat pump system to solve the problems existing in the above-mentioned prior art. By setting an intermediate gas-injection unit and two compressors, the compression ratio of the compressor is reduced, the system performance is improved, and the stability of the compressor in use is ensured.

[0007] To achieve the above purpose, the utility model provides the following scheme: The utility model provides an intermediate gas-injected heat pump system, which includes a low-pressure compressor, a high-pressure compressor, a condenser, an intermediate gas-injection unit, and an evaporator that are connected in sequence. The intermediate gas-injection unit includes a first ejector, a first gas-liquid separator, a second gas-liquid separator, and a first expansion valve. The working medium inlet of the first ejector is connected to the working medium outlet of the condenser, and the working medium outlet is connected to the first gas-liquid separator. A mixing chamber is arranged between the low-pressure compressor and the high-pressure compressor. The gas outlet of the first gas-liquid separator is connected to the mixing chamber, and the liquid outlet is connected to the working medium inlet of the first expansion valve. The working medium outlet of the first expansion valve is connected to the second gas-liquid separator. The gas outlet of the second gas-liquid separator is connected to the entrainment inlet of the first ejector, and the liquid outlet is connected to the working medium inlet of the evaporator. The working medium outlet of the evaporator is connected to the working medium inlet of the low-pressure compressor.

[0008] Preferably, a second expansion valve is arranged between the second gas-liquid separator and the evaporator.

[0009] Preferably, the second gas-liquid separator is provided with a first liquid outlet and a second liquid outlet, the low-pressure compressor is provided with a first inlet and a second inlet, the first liquid outlet is connected to the working fluid inlet of the evaporator through a valve, and the working fluid outlet of the evaporator is connected to the low-pressure compressor through the first inlet; the second liquid outlet is connected to the first working fluid inlet of the intercooler through a valve, the first working fluid outlet of the intercooler is connected to the second inlet, the second working fluid outlet of the intercooler is connected to the evaporator through a third expansion valve, the working fluid outlet of the evaporator is connected to the injection inlet of the second ejector, the working fluid outlet of the second ejector is connected to the second working fluid inlet of the intercooler, the second working fluid outlet of the intercooler is connected to the generator through a delivery pump, and the working fluid outlet of the generator is connected to the working fluid inlet of the second ejector.

[0010] Preferably, the valve is an electrically controlled valve.

[0011] Preferably, the valve is an electromagnetic reversing valve, and the first liquid outlet and the second liquid outlet are respectively connected to two liquid inlets of the electromagnetic reversing valve.

[0012] Preferably, the heat source of the generator is solar energy, an auxiliary heat source or a heat storage device.

[0013] Preferably, when the heat source of the generator is solar energy, the intermediate air supply heat pump system further comprises a light sensor for detecting external ambient light, and the light sensor and the valve are both electrically connected to a control system.

[0014] Preferably, the intercooler is a plate heat exchanger.

[0015] Preferably, the intermediate air supply heat pump system is provided with a four-way valve for exchanging the positions of the condenser and the evaporator in the flow path.

[0016] Compared with the prior art, the utility model mainly achieves the following technical effects:

[0017] By using a low-pressure compressor and a high-pressure compressor for staged compression, the compression ratio, exhaust superheat degree and system input power of the compressor can be reduced, the stability of the compressor during use can be ensured. At the same time, the intermediate gas injection unit uses a double gas-liquid separator to perform two-stage gas-liquid separation on the refrigerant working medium at the outlet of the ejector on the high-temperature cycle side of the system, enabling more saturated refrigerant vapor with higher pressure and energy to directly enter the mixing chamber, fully utilizing the energy of the refrigerant circulating working medium in the system. While increasing the heat output of the system, it can not only reduce the operating power of the high-pressure compressor, but also cause less working medium to flow into the low-pressure compressor, significantly reducing the operating power of the low-pressure compressor, and effectively improving the overall system performance; in addition, more working medium directly enters the mixing chamber without passing through the expansion valve, reducing the energy loss at the expansion valve and improving the system performance.

[0018] The following technical effects are achieved by other solutions of the present invention compared with the prior art:

[0019] As a supplementary means for the heat source of the system, the evaporator 14 cooperates with the generator 13 to increase the heat input of the system and enhance the sustainability and stability of the heat source of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic flow chart of the conventional heat input condition of the intermediate gas injection heat pump system of the present invention;

[0022] Figure 2 It is a schematic flow chart of the cascade heat input condition of the intermediate gas injection heat pump system of the present invention;

[0023] Figure 3 It is the intermediate gas injection cycle pressure-enthalpy diagram of the present invention;

[0024] Figure 4 It is the cascade heat cycle pressure-enthalpy diagram of the present invention;

[0025] Among them, 1, intermediate cooler; 2, low-pressure compressor; 3, mixing chamber; 4, high-pressure compressor; 5, condenser; 6, first gas-liquid separator; 7, first ejector; 8, first expansion valve; 9, second gas-liquid separator; 10, second expansion valve; 11, third expansion valve; 12, delivery pump; 13, generator; 14, evaporator; 15, second ejector. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] The utility model aims to provide an intermediate air supply heat pump system to solve the problems existing in the prior art, and utilizes the intermediate air supply unit and the arrangement of two compressors to reduce the compression ratio of the compressor, improve the system performance and ensure the stability of the compressor use.

[0028] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] Please refer to Figures 1 to 4 As shown, an intermediate air-supplementing heat pump system is provided, comprising a low-pressure compressor 2, a high-pressure compressor 4, a condenser 5, an intermediate air-supplementing unit and an evaporator 14 which are connected in sequence, the intermediate air-supplementing unit comprising a first ejector 7, a first gas-liquid separator 6, a second gas-liquid separator 9 and a first expansion valve 8, the working medium inlet of the first ejector 7 is connected to the working medium outlet of the condenser 5, the working medium outlet is connected to the first gas-liquid separator 6, a mixing chamber 3 is arranged between the low-pressure compressor 2 and the high-pressure compressor 4, the gas outlet of the first gas-liquid separator 6 is connected to the mixing chamber 3, the liquid outlet is connected to the working medium inlet of the first expansion valve 8, the working medium outlet of the first expansion valve 8 is connected to the second gas-liquid separator 9, the gas outlet of the second gas-liquid separator 9 is connected to the injection inlet of the first ejector 7, the liquid outlet is connected to the working medium inlet of the evaporator 14, the working medium outlet of the evaporator 14 is connected to the low-pressure compressor 2 are connected to the working medium inlet. The principle of this system is: using the low-pressure compressor 2 and the high-pressure compressor 4 for staged compression can reduce the compression ratio of the compressor, the exhaust steam superheat and the system input power, and ensure the stability of the compressor. At the same time, the intermediate air supply unit uses a double gas-liquid separator to perform two gas-liquid separations on the refrigerant working medium at the outlet of the ejector on the high-temperature circulation side of the system, so that more saturated refrigerant vapor with higher pressure and energy can directly enter the mixing chamber 3, making full use of the energy of the system refrigerant circulation working medium, increasing the system heat output, and at the same time, not only can the operating power of the high-pressure compressor 4 be reduced, but also less working medium can flow into the low-pressure compressor 2, greatly reducing the operating power of the low-pressure compressor 2, and the overall system performance is effectively improved; in addition, more working medium directly enters the mixing chamber 3 without passing through the expansion valve, reducing the energy loss at the expansion valve and improving the performance of the system.

[0030] In order to ensure the evaporation effect of the working medium in the evaporator 14 , a second expansion valve 10 is provided between the second gas-liquid separator 9 and the evaporator 14 .

[0031] In the utility model, the second gas-liquid separator 9 is provided with a first liquid outlet and a second liquid outlet, the low-pressure compressor 2 is provided with a first inlet and a second inlet, the first liquid outlet is connected to the working fluid inlet of the evaporator 14 through a valve, and the working fluid outlet of the evaporator 14 is connected to the low-pressure compressor 2 through the first inlet, which is a conventional heat input working condition; the second liquid outlet is connected to the first working fluid inlet of the intercooler 1 through a valve, the first working fluid outlet of the intercooler 1 is connected to the second inlet, and the second working fluid outlet of the intercooler 1 is connected to the evaporator 14 through the third expansion valve 11. The working fluid outlet of the evaporator 14 is connected to the injection inlet of the second ejector 15, the working fluid outlet of the second ejector 15 is connected to the second working fluid inlet of the intercooler 1, the second working fluid outlet of the intercooler 1 is connected to the generator 13 through the delivery pump 12, and the working fluid outlet of the generator 13 is connected to the working fluid inlet of the second ejector 15. This is a cascade heat input condition; that is, two evaporation heat absorption channels are set, and the evaporator 14 is used as a supplementary means of the system heat source, cooperating with the generator 13 to increase the system heat input, thereby enhancing the sustainability and stability of the system heat source.

[0032] Preferably, the valve is controlled electronically to improve the automation level of the system.

[0033] The passages of the first liquid outlet and the second liquid outlet are controlled by valves or by one valve respectively. When they are controlled by valves respectively, the valves are electrically controlled valves; when they are controlled by one valve, the valves are electromagnetic reversing valves, and the first liquid outlet and the second liquid outlet are connected to the two liquid inlets of the electromagnetic reversing valve respectively.

[0034] The heat source of the evaporator 14 is the heat in the external ambient air.

[0035] The heat source of the generator 13 is solar energy, an auxiliary heat source or a heat storage device. The solar energy can be a solar panel supplying power to an electric heating wire, the auxiliary heat source can be a gas heater, and the heat storage device can be a water heat storage device.

[0036] When the heat source of the generator 13 is solar energy, the intermediate air supply heat pump system also includes a light sensor for detecting external ambient light. The light sensor and the valve are electrically connected to the control system. The light sensor detects the external light conditions in real time. When the external ambient light is insufficient or it is at night, the control system can control the valve to switch. At this time, the generator 13, the delivery pump 12 and the second ejector 15 do not work, and the working fluid flows from the second gas-liquid separator 9 through the evaporator 14 and directly enters the low-pressure compressor 2, that is, the control system switches to the conventional heat input condition.

[0037] In order to ensure the service life and heat transfer effect, the intercooler 1 uses a plate heat exchanger. Of course, other types of heat exchangers can also be selected according to needs.

[0038] The intermediate air supply heat pump system is provided with a four-way valve for switching the positions of the condenser 5 and the evaporator 14 in the flow path, so that the system can be used for indoor cooling, and the switching method is the same as that of a conventional heat pump.

[0039] In actual use, under the condition of cascade heat input, the gaseous medium 103 from the mixing chamber 3 is compressed in the high-pressure compressor 4 to become a high-temperature and high-pressure gas 104, enters the condenser 5 to release heat, isobarically cooled to become a saturated liquid 105, and enters the first ejector 7 as a power fluid. The first ejector 7 ejects the saturated steam 110 from the second gas-liquid separator 9, and then passes through the mixing and expansion section of the first ejector 7 to increase the pressure, becoming wet steam 106 and being discharged from the first ejector 7, and then enters the first gas-liquid separator 6 to separate into saturated steam 107 and wet steam 110. Saturated liquid 108, the saturated liquid 108 obtained by the first gas-liquid separator 6 is converted into a two-phase flow 109 through the first expansion valve 8 and then enters the second gas-liquid separator 9, and is separated into saturated vapor 110 and saturated liquid 111 in the second gas-liquid separator 9. The refrigerant saturated vapor 110 enters the first ejector 7 as the ejected fluid, and the refrigerant saturated liquid 111 is throttled by the second expansion valve 10 and converted into a two-phase flow 112 and enters the intercooler 1, evaporates and absorbs the heat of the low-temperature circulation side of the system, and becomes the refrigerant saturated vapor 101 and enters the low-pressure compressor 2. The superheated gas 102 at the outlet of the low-pressure compressor 2 is mixed with the saturated steam 107 obtained from the first gas-liquid separator 6 in the mixing chamber 3, and the mixed gaseous working medium 103 is further compressed in the high-pressure compressor 4 to reach the pressure of the condenser 5. This is the intermediate gas replenishment cycle. Taking solar energy as the heat source of the generator 13 as an example: the high-pressure liquid refrigerant 115 inside the generator 13 absorbs the outdoor solar radiation heat energy, evaporates into high-temperature and high-pressure saturated steam 117, and then enters the second ejector 15. At the same time, the second ejector 15 draws the saturated steam 118 from the outlet of the evaporator 14. After the two are mixed and diffused in the second ejector 15, their pressure is increased, and they become high-temperature and high-pressure gas 113 and are discharged from the second ejector 15, and then enter the intercooler 1, and release heat to the high-temperature circulation side of the system to become saturated condensed liquid 114. Part of the condensed liquid 114 flows into the third expansion valve 11, expands into low-temperature and low-pressure wet steam 116, enters the evaporator 14, and absorbs low-grade heat from the outdoor air source to become low-temperature and low-pressure saturated steam 118. The remaining condensed liquid is sent by the delivery pump 12 to become high-pressure supercooled liquid 115 and then enters the generator 13. This is a superimposed heat cycle.

[0040] The conventional heat input condition only involves the intermediate gas injection cycle. Different from the intermediate gas injection cycle of the cascade heat input condition, the saturated refrigerant liquid separated by the second gas-liquid separator 9 is throttled by the second expansion valve 10 and then enters the evaporator 14. The evaporator 14 evaporates and absorbs the low-grade heat of the air source and becomes saturated refrigerant vapor, which enters the low-pressure compressor 2.

[0041] The refrigerants in the two cycles can be the same or different.

[0042] Any adaptive changes made according to actual requirements are within the protection scope of the present invention.

[0043] It should be noted that for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed by the present invention. Any reference signs in the claims should not be regarded as limiting the claimed invention.

[0044] Specific examples are used in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An intermediate air supply heat pump system, characterized in that: It includes a low-pressure compressor, a high-pressure compressor, a condenser, an intermediate air supply unit and an evaporator which are connected in sequence. The intermediate air supply unit includes a first ejector, a first gas-liquid separator, a second gas-liquid separator and a first expansion valve. The working fluid inlet of the first ejector is connected to the working fluid outlet of the condenser, and the working fluid outlet is connected to the first gas-liquid separator. A mixing chamber is arranged between the low-pressure compressor and the high-pressure compressor. The gas outlet of the first gas-liquid separator is connected to the mixing chamber, and the liquid outlet is connected to the working fluid inlet of the first expansion valve. The working fluid outlet of the first expansion valve is connected to the second gas-liquid separator. The gas outlet of the second gas-liquid separator is connected to the injection inlet of the first ejector, and the liquid outlet is connected to the working fluid inlet of the evaporator. The working fluid outlet of the evaporator is connected to the working fluid inlet of the low-pressure compressor.

2. The intermediate air supply heat pump system according to claim 1, characterized in that: A second expansion valve is provided between the second gas-liquid separator and the evaporator.

3. The intermediate air supply heat pump system according to claim 1, characterized in that: The second gas-liquid separator is provided with a first liquid outlet and a second liquid outlet, the low-pressure compressor is provided with a first inlet and a second inlet, the first liquid outlet is connected to the working fluid inlet of the evaporator through a valve, and the working fluid outlet of the evaporator is connected to the low-pressure compressor through the first inlet; The second liquid outlet is connected to the first working fluid inlet of the intercooler through a valve, the first working fluid outlet of the intercooler is connected to the second inlet, the second working fluid outlet of the intercooler is connected to the evaporator through a third expansion valve, the working fluid outlet of the evaporator is connected to the injection inlet of the second ejector, the working fluid outlet of the second ejector is connected to the second working fluid inlet of the intercooler, the second working fluid outlet of the intercooler is connected to the generator through a delivery pump, and the working fluid outlet of the generator is connected to the working fluid inlet of the second ejector.

4. The intermediate air supply heat pump system according to claim 3, characterized in that: The valve is an electrically controlled valve.

5. The intermediate air supply heat pump system according to claim 3, characterized in that: The valve is an electromagnetic reversing valve, and the first liquid outlet and the second liquid outlet are respectively connected to two liquid inlets of the electromagnetic reversing valve.

6. The intermediate air supply heat pump system according to claim 4 or 5, characterized in that: The heat source of the generator is solar energy, an auxiliary heat source or a heat storage device.

7. The intermediate air supply heat pump system according to claim 6, characterized in that: When the heat source of the generator is solar energy, the intermediate air supply heat pump system further comprises a light sensor for detecting external ambient light, and the light sensor and the valve are both electrically connected to a control system.

8. The intermediate air supply heat pump system according to claim 3, characterized in that: The intercooler is a plate heat exchanger.

9. The intermediate air supply heat pump system according to claim 1, characterized in that: The intermediate air supply heat pump system is provided with a four-way valve for exchanging the positions of the condenser and the evaporator in the flow path.

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