Cooling and heating combined supply system based on transcritical carbon dioxide heat pump coupling jet type refrigeration

Abstract

The invention relates to the technical field of refrigeration and heat supply, in particular to a combined cooling and heating system based on transcritical carbon dioxide heat pump coupling injection type refrigeration, which comprises a compressor, an air cooler connected with the output end of the compressor, an injector connected with the output end of the air cooler, and a condenser and an evaporator which are respectively connected with the injector, wherein one output end of the condenser is connected with the input end of the heat exchanger, and the other output end of the condenser is connected with the input end of the evaporator through the throttling valve; the output end of the heat exchanger is connected with the input end of the compressor; the input end of the condenser is connected with the output end of the ejector; the air cooler is connected with the first input end of the ejector, and the output end of the evaporator is connected with the second input end of the ejector. The performance of the coupling system can be improved while cooling and heating are achieved, on one hand, high-temperature heat and low-temperature heat can be provided, on the other hand, medium-temperature heat can be provided, and the comprehensive performance of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration and heating, and in particular to a combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration. Background Art

[0002] The combined cooling and heating system is a heating and cooling system that utilizes energy in an integrated manner. Its design purpose is to maximize energy efficiency while meeting the comfortable temperature requirements inside the building. Traditional cooling and heating systems usually use compression chillers and boilers. These devices consume a lot of electricity or fuel during operation and emit a large amount of greenhouse gases such as CO2, which has a negative impact on the environment. In order to meet the dual challenges of environmental protection and energy efficiency, researchers have begun to explore the use of new energy technologies to replace traditional heating and cooling equipment. Among them, carbon dioxide has become a highly regarded solution due to its environmentally friendly characteristics of ODP of 0, GWP of 1 and its excellent thermodynamic properties. The ejector refrigeration system is a technology that uses pressure difference and heat exchange to achieve energy transfer. It has the advantages of simple structure and high energy efficiency, and has broad application prospects in cooling systems.

[0003] In this regard, for example, the patent with publication number CN118776164A discloses a transcritical carbon dioxide compression-injection dual-temperature evaporator combined heat and cold supply system. By connecting components such as a gas-liquid separator, a medium-temperature evaporator, a low-temperature evaporator, a high-pressure compressor, a low-pressure compressor, a gas cooler, an ejector, a regenerator, a medium-temperature throttle valve, and a low-temperature throttle valve, the refrigeration performance and energy efficiency of the transcritical carbon dioxide compression-injection dual-temperature evaporator combined heat and cold supply system can be effectively improved. In addition, the transcritical carbon dioxide compression-injection dual-temperature evaporator combined heat and cold supply system in the disclosed technology provides a refrigeration system with two different evaporation temperatures to meet the refrigeration needs of a dual-temperature zone environment, thereby reducing costs.

[0004] Although the above disclosed technology can meet the use requirements of dual temperature zones, the compressors required include a high-pressure compressor and a low-pressure compressor. Based on this, the piping design of the overall system becomes more complicated, which increases the use cost of the system.

[0005] Therefore, in terms of the transcritical carbon dioxide combined heating and cooling system, on the basis of taking into account its need to meet the use requirements of different temperature zones, it is also necessary to further optimize its structure in terms of simplifying its overall piping structure. Summary of the invention

[0006] The purpose of the present invention is to provide a combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with an ejector refrigeration system, so as to solve the technical problems of simplifying the overall piping structure and reducing the use cost.

[0007] The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration of the present invention is implemented as follows: A combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with an ejector refrigeration system comprises: a compressor, an air cooler connected to the output end of the compressor, an ejector connected to the output end of the air cooler, and a condenser and an evaporator respectively connected to the ejector; wherein One output end of the condenser is connected to the input end of the heat exchanger, and the other output end of the condenser is connected to the input end of the evaporator through a throttle valve; and the output end of the heat exchanger is connected to the input end of the compressor; The input end of the condenser is connected to the output end of the ejector; the air cooler is connected to the first input end of the ejector, and the output end of the evaporator is connected to the second input end of the ejector.

[0008] In an optional implementation of the present invention, carbon dioxide working medium flows between the compressor, the air cooler, the ejector, the condenser, the throttle valve and the evaporator.

[0009] In an optional implementation of the present invention, the compressor is used to compress low-pressure and low-temperature carbon dioxide gas into high-pressure and high-temperature transcritical carbon dioxide.

[0010] In an optional implementation of the present invention, the air cooler is used to cool high-temperature and high-pressure transcritical carbon dioxide; and the air cooler is also suitable for heat exchange with the medium-temperature water pipe to convert the medium-temperature hot water in the medium-temperature water pipe into high-temperature hot water.

[0011] In an optional implementation of the present invention, the heat exchanger also uses heat exchange with high-temperature hot water to heat and gasify the liquid carbon dioxide.

[0012] In an optional embodiment of the present invention, the ejector is suitable for mixing high-pressure and high-temperature carbon dioxide gas with low-pressure and low-temperature carbon dioxide gas to form a medium-pressure and medium-temperature carbon dioxide fluid.

[0013] In an optional implementation of the present invention, the condenser is used to condense medium-temperature and medium-pressure carbon dioxide fluid into liquid carbon dioxide; and The condenser is also suitable for heat exchange with the cooling water pipe to convert the normal temperature cold water in the cold water pipe into medium temperature hot water.

[0014] In an optional implementation of the present invention, the liquid carbon dioxide formed by the condenser is divided into two paths, one of which is throttled and reduced in pressure by a throttle valve to become a low-pressure and low-temperature carbon dioxide liquid. After entering the evaporator, the low-pressure and low-temperature carbon dioxide liquid absorbs heat and evaporates into a low-pressure and low-temperature carbon dioxide gas.

[0015] In an optional implementation of the present invention, the evaporator is also suitable for heat exchange with the cold water pipe to convert the normal temperature cold water in the cold water pipe into low temperature cold water.

[0016] In an optional implementation of the present invention, another path of liquid carbon dioxide formed by the condenser is heat exchanged with high-temperature hot water through a heat exchanger to reach a carbon dioxide gas close to the initial temperature, and then returns to the compressor.

[0017] By adopting the above technical scheme, the present invention has the following beneficial effects: the combined heat and cold supply system based on the transcritical carbon dioxide heat pump coupled with the jet refrigeration of the present invention adopts the natural working fluid transcritical carbon dioxide heat pump system coupled with the jet refrigeration combined heat and cold supply system, which can improve the performance of the coupling system while realizing the supply of heat and cold. On the one hand, it can provide high-temperature heat and low-temperature heat, and at the same time, it can provide medium-temperature heat, and the comprehensive performance of the system is improved; on the other hand, the ejector is used to recover part of the throttling loss, and the energy efficiency ratio of the system is improved. In addition, the use of environmentally friendly working fluid carbon dioxide replaces the traditional refrigerant, reduces the emission of greenhouse gases, and at the same time, can provide a high-quality heat source for the jet refrigeration system. The ejector can recover the expansion work of the transcritical carbon dioxide system and improve the system performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Shown is a structural schematic diagram of a combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with ejection refrigeration according to the present invention.

[0019] In the figure: compressor 1, air cooler 2, ejector 3, condenser 4, heat exchanger 5, throttle valve 6, evaporator 7, heat usage scene 8, living heating area 9. DETAILED DESCRIPTION

[0020] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0021] See also Figure 1 As shown, this embodiment provides a combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with ejector refrigeration, comprising: a compressor 1, an air cooler 2 connected to the output end of the compressor 1, an ejector 3 connected to the output end of the air cooler 2, and a condenser 4 and an evaporator 7 respectively connected to the ejector 3; wherein the ejector 3 realizes cooling on the evaporator 7 side and heating on the condenser 4 side, while increasing the pressure of the gas returned to the compressor 1.

[0022] Specifically, one output end of the condenser 4 is connected to the input end of the heat exchanger 5, and the other output end of the condenser 4 is connected to the input end of the evaporator 7 through the throttle valve 6; and the output end of the heat exchanger 5 is connected to the input end of the compressor 1; the input end of the condenser 4 is connected to the output end of the ejector 3; the air cooler 2 is connected to the first input end of the ejector 3, and the output end of the evaporator 7 is connected to the second input end of the ejector 3.

[0023] Based on the above situation, it should be noted that in this embodiment, carbon dioxide is circulated between the compressor 1, the air cooler 2, the ejector 3, the condenser 4, the throttle valve 6 and the evaporator 7. The use of environmentally friendly carbon dioxide replaces traditional refrigerants and reduces greenhouse gas emissions.

[0024] In more detail, the compressor 1 of this embodiment is used to compress low-pressure and low-temperature carbon dioxide gas into high-pressure and high-temperature transcritical carbon dioxide. The air cooler 2 is used to cool the high-temperature and high-pressure transcritical carbon dioxide; and the air cooler 2 is also suitable for heat exchange with the medium-temperature water pipe to form high-temperature hot water from the medium-temperature hot water in the medium-temperature water pipe. The heat exchanger 5 also uses heat exchange with the high-temperature hot water to heat and gasify the liquid carbon dioxide to prevent liquid hammer from occurring in the compressor 1. The ejector 3 is suitable for mixing the high-pressure and high-temperature carbon dioxide gas with the low-pressure and low-temperature carbon dioxide gas to form a medium-pressure and medium-temperature carbon dioxide fluid.

[0025] Furthermore, the condenser 4 is used to condense the medium-temperature and medium-pressure carbon dioxide fluid into liquid carbon dioxide; and the condenser 4 is also suitable for heat exchange with the cooling water pipe to convert the normal-temperature cold water in the cold water pipe into medium-temperature hot water. The liquid carbon dioxide formed by the condenser 4 is divided into two paths, one of which is throttled and reduced in pressure by the throttle valve 6 to become a low-pressure and low-temperature carbon dioxide liquid. The low-pressure and low-temperature carbon dioxide liquid enters the evaporator 7 and absorbs heat to evaporate into a low-pressure and low-temperature carbon dioxide gas. The evaporator 7 is also suitable for heat exchange with the cold water pipe to convert the normal-temperature cold water in the cold water pipe into low-temperature cold water. The other path of liquid carbon dioxide formed by the condenser 4 is heat-exchanged with high-temperature hot water through the heat exchanger 5 to reach a carbon dioxide gas close to the initial temperature, and then returns to the compressor 1.

[0026] In summary, for the combined cooling and heating system based on the transcritical carbon dioxide heat pump coupled with ejection refrigeration in this embodiment, the specific implementation principle is as follows: The low-pressure and low-temperature carbon dioxide gas enters the compressor 1 and is compressed into high-pressure and high-temperature transcritical carbon dioxide; the high-pressure and high-temperature carbon dioxide gas enters the air cooler and forms high-temperature hot water with the medium-temperature hot water in the medium-temperature water pipe, which can be used in water heater heating, pasteurization or blanching and other heat-using scenarios 8; the high-pressure and high-temperature carbon dioxide gas enters the ejector 3, and is mixed in the mixing chamber by the injection of low-pressure and low-temperature carbon dioxide gas to form a medium-pressure and medium-temperature carbon dioxide fluid that enters the condenser 4. The carbon dioxide fluid exchanges heat with the cooling water pipe to convert the normal-temperature cold water in the cold water pipe into medium-temperature hot water, which can be used in the domestic heating area 9. One path of liquid carbon dioxide is throttled and reduced in pressure by the throttle valve 6 to become a low-pressure The low-temperature carbon dioxide liquid, after entering the evaporator 7, absorbs heat and evaporates into low-pressure and low-temperature carbon dioxide gas. The evaporator 7 simultaneously exchanges heat with the cold water pipe to convert the normal-temperature cold water in the cold water pipe into low-temperature cold water, which can be used in occasions such as but not limited to data centers that require cooling. The low-pressure and low-temperature carbon dioxide gas here is injected into the ejector 3 again, and the high-pressure and high-temperature carbon dioxide gas is injected and mixed in the mixing chamber to form a medium-pressure and medium-temperature carbon dioxide fluid, starting a new round of circulation; the other liquid carbon dioxide is exchanged with high-temperature hot water through the heat exchanger 5 to reach a carbon dioxide gas close to the initial temperature, and then returns to the compressor 1. Therefore, the combined heat and cold supply system based on the transcritical carbon dioxide heat pump coupled with the ejector refrigeration of this embodiment can improve the performance of the coupled system while achieving cooling and heating. On the one hand, it can provide high-temperature heat and low-temperature heat, and at the same time, it can provide medium-temperature heat, and the overall performance of the system is improved.

[0027] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0028] In the description of the present invention, it is necessary to understand that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, unless otherwise clearly specified and limited, a first feature being above or below a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, a first feature being above, above, and above a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being below, below, and below a second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

Claims

1. A combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration, characterized in that: include: A compressor, an air cooler connected to an output end of the compressor, an ejector connected to an output end of the air cooler, and a condenser and an evaporator respectively connected to the ejector; in One output end of the condenser is connected to the input end of the heat exchanger, and the other output end of the condenser is connected to the input end of the evaporator through a throttle valve; and the output end of the heat exchanger is connected to the input end of the compressor; The input end of the condenser is connected to the output end of the ejector; the air cooler is connected to the first input end of the ejector, and the output end of the evaporator is connected to the second input end of the ejector.

2. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 1 is characterized in that: Carbon dioxide working medium flows among the compressor, the air cooler, the ejector, the condenser, the throttle valve and the evaporator.

3. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 2 is characterized in that: The compressor is used to compress low-pressure and low-temperature carbon dioxide gas into high-pressure and high-temperature transcritical carbon dioxide.

4. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 3 is characterized in that: The air cooler is used to cool high-temperature and high-pressure transcritical carbon dioxide; and the air cooler is also suitable for heat exchange with the medium-temperature water pipe to convert the medium-temperature hot water in the medium-temperature water pipe into high-temperature hot water.

5. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 4 is characterized in that: The heat exchanger also heats and vaporizes the liquid carbon dioxide by heat exchange with high-temperature hot water.

6. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 5 is characterized in that: The ejector is suitable for mixing high-pressure and high-temperature carbon dioxide gas with low-pressure and low-temperature carbon dioxide gas to form medium-pressure and medium-temperature carbon dioxide fluid.

7. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 6 is characterized in that: The condenser is used to condense medium-temperature and medium-pressure carbon dioxide fluid into liquid carbon dioxide; and The condenser is also suitable for heat exchange with the cooling water pipe to convert the normal temperature cold water in the cold water pipe into medium temperature hot water.

8. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 7 is characterized in that: The liquid carbon dioxide formed by the condenser is divided into two paths. One path of the liquid carbon dioxide is throttled and reduced in pressure by a throttle valve to become low-pressure and low-temperature carbon dioxide liquid. The low-pressure and low-temperature carbon dioxide liquid enters the evaporator and absorbs heat to evaporate into low-pressure and low-temperature carbon dioxide gas.

9. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 8, characterized in that: The evaporator is also suitable for heat exchange with the cold water pipe to convert the normal temperature cold water in the cold water pipe into low temperature cold water.

10. The combined cooling and heating system based on a transcritical carbon dioxide heat pump coupled with jet refrigeration according to claim 8 or 9, characterized in that: The other liquid carbon dioxide formed by the condenser exchanges heat with high-temperature hot water through a heat exchanger to reach a carbon dioxide gas temperature close to the initial temperature, and then returns to the compressor.

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