A refrigeration system employing dual ejectors

Abstract

This invention discloses a refrigeration system employing dual ejectors, relating to the field of compression refrigeration technology. The system includes a condenser, a working fluid pump, a generator, a two-phase ejector, a steam ejector, a gas-liquid separator, a scroll compressor, and an evaporator. The condenser outlet is connected to the working fluid pump inlet, the working fluid pump outlet is connected to both the generator inlet and the primary flow inlet of the two-phase ejector, the generator outlet is connected to the primary flow inlet of the steam ejector, the two-phase ejector outlet is connected to the gas-liquid separator inlet, the gas outlet of the gas-liquid separator is connected to the scroll compressor inlet, the liquid outlet of the gas-liquid separator is connected to the evaporator inlet, the evaporator outlet is connected to the secondary flow inlet of the two-phase ejector, the scroll compressor outlet is connected to the secondary flow inlet of the steam ejector, and the steam ejector outlet is connected to the condenser inlet. This invention improves the efficiency and performance of the entire system, thereby achieving higher operational efficiency.

Description

Technical Field

[0001] This invention relates to the field of refrigeration, and in particular to a refrigeration system employing dual ejectors. Background Technology

[0002] According to the International Energy Agency (IEA), approximately 40% of global energy consumption is used for heating, cooling, ventilation, and air conditioning (RHVAC) systems, with air conditioning systems being one of the largest consumers of electrical equipment. It is projected that by 2050, two-thirds of buildings worldwide will have air conditioning systems installed, further increasing energy demand and carbon emission pressures. Currently, most air conditioning systems use vapor compression refrigeration technology, with mechanical compressors accounting for over 80% of total energy consumption. To address this challenge, it is necessary to develop and promote more efficient and energy-saving air conditioning technologies, such as jet refrigeration and absorption refrigeration technologies, to reduce energy consumption and carbon emissions.

[0003] Jet refrigeration systems utilize low-temperature heat sources to drive the refrigeration cycle, achieving energy conservation and environmental protection. For example, solar and geothermal energy can be used as driving energy sources for jet refrigeration systems, which helps reduce the use of fossil fuels and carbon emissions. Furthermore, industrial waste heat can be recovered and utilized through jet refrigeration systems, improving energy efficiency and reducing production costs. Compared to vapor compression refrigeration systems, jet refrigeration systems face some challenges in the market. One major influencing factor is their lower coefficient of performance (COP), typically less than 0.5. This means that jet refrigeration systems require more energy to produce the same cooling effect, leading to increased operating costs.

[0004] Currently, there is an urgent need to propose a refrigeration system that couples injection and compression to fully utilize low-grade heat energy, reduce compression power consumption, and improve system performance. Summary of the Invention

[0005] The purpose of this invention is to provide a refrigeration system using dual injectors, which makes full use of low-grade heat energy and reduces compression power consumption, thereby improving system performance.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A refrigeration system employing dual ejectors includes: a condenser, a working fluid pump, a generator, a two-phase ejector, a vapor ejector, a gas-liquid separator, a scroll compressor, and an evaporator; the outlet of the condenser is connected to the inlet of the working fluid pump, the outlet of the working fluid pump is connected to the inlet of the generator and the primary inlet of the two-phase ejector, the outlet of the generator is connected to the primary inlet of the vapor ejector, the outlet of the two-phase ejector is connected to the inlet of the gas-liquid separator, the gas outlet of the gas-liquid separator is connected to the inlet of the scroll compressor, the liquid outlet of the gas-liquid separator is connected to the inlet of the evaporator, the outlet of the evaporator is connected to the secondary inlet of the two-phase ejector, the outlet of the scroll compressor is connected to the secondary inlet of the vapor ejector, and the outlet of the vapor ejector is connected to the inlet of the condenser.

[0008] Optionally, the generator is used to absorb low-grade thermal energy, including solar energy, geothermal energy, and waste heat generated by the compression-jet refrigeration system.

[0009] Optionally, it also includes an expansion valve; the liquid output from the gas outlet of the gas-liquid separator enters the evaporator through the expansion valve.

[0010] Optionally, it also includes a three-way valve, the inlet of which is connected to the inlet of the working fluid pump, the first outlet of which is connected to the inlet of the generator, and the second outlet of which is connected to the primary flow inlet of the two-phase injector.

[0011] The present invention also discloses a refrigeration system employing dual ejectors, comprising: a condenser, a working fluid pump, a generator, a two-phase ejector, a steam ejector, a gas-liquid separator, and an evaporator; the outlet of the condenser is connected to the inlet of the working fluid pump, the outlet of the working fluid pump is connected to the inlet of the generator and the primary inlet of the two-phase ejector, the outlet of the generator is connected to the primary inlet of the steam ejector, the outlet of the two-phase ejector is connected to the inlet of the gas-liquid separator, the gas outlet of the gas-liquid separator is connected to the secondary inlet of the steam ejector, the liquid outlet of the gas-liquid separator is connected to the inlet of the evaporator, the outlet of the evaporator is connected to the secondary inlet of the two-phase ejector, and the outlet of the steam ejector is connected to the inlet of the condenser.

[0012] Optionally, the generator is used to absorb low-grade heat energy, including solar energy, geothermal energy, and waste heat generated by the refrigeration system.

[0013] Optionally, it also includes an expansion valve; the liquid output from the gas outlet of the gas-liquid separator enters the evaporator through the expansion valve.

[0014] Optionally, it also includes a three-way valve, the inlet of which is connected to the inlet of the working fluid pump, the first outlet of which is connected to the inlet of the generator, and the second outlet of which is connected to the primary flow inlet of the two-phase injector.

[0015] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0016] This invention utilizes a gas-to-gas ejector as the steam ejector, which replaces the scroll compressor to compress the evaporator outlet vapor to the condenser pressure. This cycle is called a heat-driven jet refrigeration cycle. The two-phase ejector is a gas-to-liquid ejector, which can be used as an expansion device to recover expansion work. This cycle includes a scroll compressor and is called an ejector expansion refrigeration cycle. The dual-ejector refrigeration cycle combines the heat-driven ejector with the ejector expansion refrigeration cycle, with a cryogenic ejector replacing the expansion device to reduce throttling losses. The gas-to-liquid ejector can provide a larger intake flow rate, thereby reducing the load on the gas-to-gas ejector. The gas-to-gas ejector entrains the working fluid discharged from the scroll compressor and delivers the total working fluid to the condenser. This design improves the efficiency and performance of the entire system, resulting in higher operating performance. Furthermore, this invention fully utilizes low-grade heat energy and reduces compression power consumption, improving system performance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a refrigeration system using dual ejectors is provided as an embodiment of the present invention;

[0019] Figure 2 A pressure-enthalpy diagram of a refrigeration system employing dual injectors is provided for an embodiment of the present invention.

[0020] Symbol explanation:

[0021] First pipe—1, Second mixing chamber—2, Second diffuser—3, Second pipe—4, Third pipe—5, Fourth pipe—6, First mixing chamber—7, First diffuser—8, Fifth pipe—9, Sixth pipe—10, Liquid outlet of gas-liquid separator—11, Inlet of evaporator—12, Seventh pipe—13, Eighth pipe—14, Working fluid pump—15, Generator—16, Condenser—17, Two-phase ejector—18, Steam ejector—19, Gas-liquid separator—20, Scroll compressor—21, Evaporator—22, Expansion valve—23. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The purpose of this invention is to provide a refrigeration system using dual injectors, which makes full use of low-grade heat energy and reduces compression power consumption, thereby improving system performance.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Vapor compression refrigeration cycles consume significant amounts of electricity, leading to fuel consumption and greenhouse gas emissions. Absorption, adsorption, and jet refrigeration cycles have the potential to significantly reduce energy consumption. These cycles use waste heat and renewable energy sources such as solar and geothermal energy as driving forces, avoiding fuel consumption and greenhouse gas emissions.

[0026] Jet refrigeration systems offer advantages such as simple structure, reliable operation, and low cost and maintenance. Compared to complex and expensive absorption refrigeration systems, jet refrigeration systems can effectively compete when the heat source temperature is below 80°C.

[0027] This invention considers using recycled waste heat and renewable energy sources (such as solar and geothermal energy) as driving energy sources, and takes advantage of jet refrigeration systems.

[0028] Example 1

[0029] This embodiment provides a refrigeration system employing dual ejectors, such as Figure 1As shown, a refrigeration system employing dual ejectors includes: a condenser 17, a working fluid pump 15, a generator 16, a two-phase ejector 18, a steam ejector 19, a gas-liquid separator 20, a scroll compressor 21, and an evaporator 22; the outlet of the condenser 17 is connected to the inlet of the working fluid pump 15, the outlet of the working fluid pump 15 is connected to the inlet of the generator 16 and the primary inlet of the two-phase ejector 18, the outlet of the generator 16 is connected to the primary inlet of the steam ejector 19, the outlet of the two-phase ejector 18 is connected to the inlet of the gas-liquid separator 20, the gas outlet of the gas-liquid separator 20 is connected to the inlet of the scroll compressor 21, the liquid outlet 11 of the gas-liquid separator is connected to the inlet 12 of the evaporator, the outlet of the evaporator 22 is connected to the secondary inlet of the two-phase ejector 18, the outlet of the scroll compressor 21 is connected to the secondary inlet of the steam ejector 19, and the outlet of the steam ejector 19 is connected to the inlet of the condenser 17.

[0030] This invention introduces a heat-driven jet refrigeration cycle into the ejector expansion refrigeration cycle, which utilizes the expansion work from the pressure of condenser 17 to the pressure of evaporator 22 to improve the performance of the ejector refrigeration system and reduce the mechanical power input of scroll compressor 21.

[0031] The generator 16 is used to absorb low-grade heat energy, including solar energy, geothermal energy, and waste heat generated by the compression-jet refrigeration system. The generator 16 can utilize solar energy, geothermal energy, or low-grade industrial waste heat to drive the steam ejector 19, thereby avoiding fuel consumption and greenhouse gas emissions.

[0032] A refrigeration system employing dual ejectors also includes an expansion valve 23; the liquid output from the gas outlet of the gas-liquid separator 20 enters the evaporator 22 through the expansion valve 23.

[0033] A refrigeration system employing dual ejectors further includes a three-way valve, the inlet of which is connected to the inlet of the working fluid pump 15, the first outlet of which is connected to the inlet of the generator 16, and the second outlet of which is connected to the primary flow inlet of the two-phase ejector 18.

[0034] The working process of the two-phase ejector 18 and the steam ejector 19 is as follows: the main stream of superheated steam enters the main nozzle, where its pressure and temperature decrease while its velocity increases. The secondary stream, under low pressure, enters the mixing chamber. Furthermore, the pressure and temperature of the secondary stream entering the mixing chamber also decrease. The two fluids mix, and the mixing pressure is lower than the pressure of the evaporator 22, so that the secondary stream is drawn into the mixing chamber. At the ejector outlet, the pressure of the mixed stream increases, and its velocity decreases until the flow almost stops.

[0035] The two-phase injector 18 includes a first mixing chamber 7 and a first diffuser 8, and the steam injector 19 includes a second mixing chamber 2 and a second diffuser 3.

[0036] The specific workflow of the dual-ejector refrigeration system of this invention includes: the fluid at the outlet of condenser 17 is pressurized to the pressure of generator 16 by working fluid pump 15, and then divided into two parts using a three-way valve with one inlet and two outlets. One part of the fluid passes through generator 16, absorbs low-grade heat energy and becomes saturated steam, becoming the primary flow of the high-temperature ejector (steam ejector 19), used to increase the discharge pressure of scroll compressor 21 (secondary flow). The high-temperature ejector increases the pressure of the mixed flow to the pressure of condenser 17. The other part of the fluid, as the primary flow, enters the low-temperature ejector (two-phase ejector 18). The secondary flow comes from the outlet of evaporator 22 and is a two-phase fluid, so the mixed flow enters gas-liquid separator 20. The saturated steam flow output from gas-liquid separator 20 enters scroll compressor 21, and the saturated liquid flow enters evaporator 22 after passing through expansion valve 23 to absorb heat, achieving a cooling effect.

[0037] The pressure-enthalpy diagram of the refrigeration system using dual ejectors in this invention is shown below. Figure 2 As shown, Figure 2 The vertical axis represents pressure P, and the horizontal axis represents enthalpy h. Pipe 1 is the pipe between generator 16 and two-phase ejector 18; pipe 4 is the pipe between two-phase ejector 18 and condenser 17; pipe 5 is the pipe between condenser 17 and working fluid pump 15; pipe 6 is the pipe between working fluid pump 15 and generator 16; pipe 9 is the pipe between gas-liquid separator 20 and two-phase ejector 18; pipe 10 is the pipe between gas-liquid separator 20 and scroll compressor 21; pipe 13 is the pipe between evaporator 22 and two-phase ejector 18; pipe 14 is the pipe between scroll compressor 21 and steam ejector 19; 13' is the state point at the nozzle outlet of two-phase ejector 18; and 14' is the state point at the nozzle outlet of steam ejector 19.

[0038] The core of this invention's compression refrigeration system is to utilize the physical properties of fluids at different temperatures, and leverage the ejector's induction, mixing, and pressurization functions to achieve heat transfer and conversion. Under the same operating conditions, a dual-ejector refrigeration cycle can produce higher refrigeration efficiency than a refrigeration cycle using a single thermally driven ejector.

[0039] The high-temperature ejector of this invention is a gas-to-gas ejector (both primary and secondary flows are dry gas). The gas-to-gas ejector replaces the scroll compressor 21 to compress the outlet vapor of the evaporator 22 to the pressure of the condenser 17. This cycle is called a heat-driven jet refrigeration cycle. The low-temperature ejector is a gas-to-liquid ejector (the primary flow is liquid, and the secondary flow is gas). The gas-to-liquid ejector serves as an expansion device to recover expansion work. This cycle includes the scroll compressor 21 and is called an ejector expansion refrigeration cycle. The primary flow of the high-temperature ejector is saturated dry working fluid leaving the generator 16.

[0040] The dual-ejector refrigeration cycle of this invention combines a thermally driven ejector with an ejector expansion refrigeration cycle. A low-temperature ejector replaces the expansion device to reduce throttling losses. The high-temperature ejector ejects the working fluid discharged from the scroll compressor 21 and delivers the total working fluid to the condenser 17, thereby reducing the energy consumption of the scroll compressor 21.

[0041] This invention incorporates a scroll compressor at the steam ejector inlet, effectively increasing the secondary fluid inlet pressure, improving steam ejector performance, and preventing malfunctions. The gaseous refrigerant compressed by the scroll compressor enters the steam ejector, reducing compressor power consumption and effectively improving system refrigeration performance. The two-phase ejector, scroll compressor, and steam ejector jointly handle the refrigerant compression, reducing power consumption and improving system energy efficiency. This invention adds a two-phase ejector and a gas-liquid separator to the existing solar-powered jet refrigeration system, utilizing the expansion energy from the condenser to the evaporator to enhance system performance.

[0042] Example 2

[0043] This embodiment provides a refrigeration system employing dual ejectors. The system includes: a condenser 17, a working fluid pump 15, a generator 16, a two-phase ejector 18, a steam ejector 19, a gas-liquid separator 20, and an evaporator 22. The outlet of the condenser 17 is connected to the inlet of the working fluid pump 15. The outlet of the working fluid pump 15 is connected to both the inlet of the generator 16 and the primary inlet of the two-phase ejector 18. The outlet of the generator 16 is connected to the primary inlet of the steam ejector 19. The outlet of the two-phase ejector 18 is connected to the inlet of the gas-liquid separator 20. The gas outlet of the gas-liquid separator 20 is connected to the secondary inlet of the steam ejector 19. The liquid outlet of the gas-liquid separator is connected to the inlet of the evaporator 22. The outlet of the evaporator 22 is connected to the secondary inlet of the two-phase ejector 18. The outlet of the steam ejector 19 is connected to the inlet of the condenser 17.

[0044] This embodiment describes a refrigeration system using dual ejectors, suitable for applications with high evaporation temperatures. It eliminates the need for a scroll compressor 21, allowing the refrigerant gas from the gas-liquid separator 20 to directly enter the high-temperature ejector.

[0045] The generator 16 is used to absorb low-grade thermal energy, including solar energy, geothermal energy, and waste heat generated by the refrigeration system.

[0046] A refrigeration system employing dual ejectors also includes an expansion valve 23; the liquid output from the gas outlet of the gas-liquid separator 20 enters the evaporator 22 through the expansion valve 23.

[0047] A refrigeration system employing dual ejectors also includes a three-way valve, the inlet of which is connected to the inlet of the working fluid pump 15, the first outlet of which is connected to the inlet of the generator 16, and the second outlet of which is connected to the primary flow inlet of the two-phase ejector 18.

[0048] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0049] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A refrigeration system employing dual injectors, characterized by, Comprising: a condenser, a working fluid pump, a generator, a two-phase ejector, a steam ejector, a gas-liquid separator, a scroll compressor and an evaporator; an outlet of the condenser is connected to an inlet of the working fluid pump, an outlet of the working fluid pump is connected to an inlet of the generator and a primary flow inlet of the two-phase ejector respectively, an outlet of the generator is connected to a primary flow inlet of the steam ejector, an outlet of the two-phase ejector is connected to an inlet of the gas-liquid separator, a gas outlet of the gas-liquid separator is connected to an inlet of the scroll compressor, a liquid outlet of the gas-liquid separator is connected to an inlet of the evaporator, an outlet of the evaporator is connected to a secondary flow inlet of the two-phase ejector, an outlet of the scroll compressor is connected to a secondary flow inlet of the steam ejector, and an outlet of the steam ejector is connected to an inlet of the condenser.

2. The refrigeration system employing dual injectors as set forth in claim 1, wherein, The generator is used to absorb low-grade heat energy, and the low-grade heat energy includes solar energy, geothermal energy, industrial waste heat and waste heat generated by the refrigeration system.

3. The refrigeration system employing dual injectors as set forth in claim 1, wherein, Further comprising an expansion valve, and liquid output by the gas outlet of the gas-liquid separator enters the evaporator through the expansion valve.

4. The refrigeration system employing dual injectors as set forth in claim 1, wherein, Further comprising a three-way valve, an inlet of the three-way valve is connected to the inlet of the working fluid pump, a first outlet of the three-way valve is connected to the inlet of the generator, and a second outlet of the three-way valve is connected to the primary flow inlet of the two-phase ejector.

5. A refrigeration system employing dual injectors, characterized by, Comprising: a condenser, a working fluid pump, a generator, a two-phase ejector, a steam ejector, a gas-liquid separator and an evaporator; an outlet of the condenser is connected to an inlet of the working fluid pump, an outlet of the working fluid pump is connected to an inlet of the generator and a primary flow inlet of the two-phase ejector respectively, an outlet of the generator is connected to a primary flow inlet of the steam ejector, an outlet of the two-phase ejector is connected to an inlet of the gas-liquid separator, a gas outlet of the gas-liquid separator is connected to a secondary flow inlet of the steam ejector, a liquid outlet of the gas-liquid separator is connected to an inlet of the evaporator, an outlet of the evaporator is connected to a secondary flow inlet of the two-phase ejector, an outlet of the steam ejector is connected to an inlet of the condenser.

6. The refrigeration system employing dual injectors as set forth in claim 5, wherein, The generator is used to absorb low-grade heat energy, and the low-grade heat energy includes solar energy, geothermal energy, industrial waste heat and waste heat generated by the refrigeration system.

7. The refrigeration system employing dual injectors as set forth in claim 5, wherein, Further comprising an expansion valve, and liquid output by the gas outlet of the gas-liquid separator enters the evaporator through the expansion valve.

8. The refrigeration system employing dual injectors as set forth in claim 5, wherein, Further comprising a three-way valve, an inlet of the three-way valve is connected to the inlet of the working fluid pump, a first outlet of the three-way valve is connected to the inlet of the generator, and a second outlet of the three-way valve is connected to the primary flow inlet of the two-phase ejector.

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