Heat exchange tube, heat exchange device, cascade unit and combined cooling and heating system

Abstract

The utility model relates to a heat exchange tube, a heat exchange device, a cascade unit and a cold and heat cogeneration system, the heat exchange tube comprises a tube body and a first heat exchange structure, and the tube body is internally provided with a first channel used for containing a first working medium; the multiple first heat exchange structures are arranged on the peripheral face of the pipe body and used for making contact with a second working medium for heat exchange; the first heat exchange structure comprises a heat exchange main body and a turbulent flow part which are in angular connection. The first heat exchange structure of the heat exchange tube comprises the heat exchange main body and the turbulent flow part which are in angular connection, in the process that the second working medium firstly makes contact with the heat exchange main body and flows to the peripheral face of the tube body along the heat exchange main body, part of the second working medium makes contact with the turbulent flow part, turning of the flowing direction is achieved, and heat exchange efficiency is improved. Therefore, turbulent motion is generated at the turbulent flow part, the first heat exchange structure and a flowing boundary layer outside the tube body are damaged by enhancing disturbance on the second working medium, and the heat transfer efficiency and the heat exchange effect of the heat exchange tube can be improved.

Description

Technical Field

[0001] This application relates to the field of heat exchange technology, and in particular to a heat exchange tube, a heat exchange device, a cascade unit, and a combined cooling and heating system. Background Technology

[0002] In industrial production, food and medical industries, energy industries, and daily life, heat exchange devices are often used to achieve heat exchange between two or more substances, thereby achieving effects such as temperature control, energy transfer, cost reduction, and efficiency improvement.

[0003] As a core component of a heat exchange device, the heat exchange tube significantly affects the heat exchange efficiency and performance of the device. Specifically, the tube wall serves as the heat transfer medium between two working fluids, and its material and structure both influence the heat transfer coefficient and heat exchange efficiency.

[0004] To reduce manufacturing costs, heat exchange tubes in existing technologies are usually smooth tubes, that is, straight or curved tubes without special structures on the inner and outer surfaces of the tube. When the working fluid flows along the surface of the smooth tube, a stable flow boundary layer (also known as the fluid boundary layer) is generated. When the thickness of the flow boundary layer is large, the distance that heat is transferred from the fluid to the solid wall is longer, the heat transfer efficiency is lower, and the heat exchange effect of the heat exchange device is worse. Utility Model Content

[0005] This application provides a heat exchange tube, a heat exchange device, a cascade unit, and a combined cooling and heating system to solve the technical problem that when the heat exchange tube is a bare tube, a stable thickness of flow boundary layer is easily generated, resulting in low heat transfer efficiency of the heat exchange tube.

[0006] In a first aspect, this application provides a heat exchange tube, comprising:

[0007] The tube body has a first channel inside for containing the first working fluid;

[0008] The first heat exchange structure, there are multiple first heat exchange structures, which are disposed on the outer circumferential surface of the tube body for heat exchange with the second working fluid; the first heat exchange structure includes a heat exchange body and a turbulence section connected at an angle.

[0009] Optionally, the heat exchanger body extends radially along the tube body, and the turbulence-dispersing part extends axially along the tube body.

[0010] Optionally, the heat exchanger body may have protrusions on one or both sides.

[0011] Optionally, a second heat exchange structure is provided on the inner circumferential surface of the tube to increase the heat exchange area inside the first channel.

[0012] Optionally, there are multiple second heat exchange structures, which are arranged in a spiral shape on the inner circumferential surface of the tube body to form multiple spiral grooves on the inner circumferential surface of the tube body.

[0013] Secondly, this application provides a heat exchange device, including the heat exchange tube provided in the first aspect of this application, and also includes a housing, the interior of which has a cavity for containing a second working fluid, and the heat exchange tube is disposed inside the cavity.

[0014] Optionally, a flow equalization element is provided in the end cap at one end of the shell, and multiple heat exchange tubes are arranged in parallel inside the cavity. The side of the end cap away from the cavity has a first working fluid inlet. In the flow direction of the first working fluid, the flow equalization element is provided at the front end of the multiple heat exchange tubes.

[0015] Thirdly, this application provides a cascade unit, including the heat exchange device provided in the second aspect of this application, and further including a high-temperature stage system and a low-temperature stage system. The heat exchange device is an evaporator-condenser in the cascade unit, and the heat exchange device is connected to the high-temperature stage system and the low-temperature stage system respectively.

[0016] Optionally, the refrigerant circulating in the high-temperature stage system is the first working fluid, and the refrigerant circulating in the low-temperature stage system is the second working fluid, and the first working fluid and the second working fluid are of different types.

[0017] Optionally, the first working medium is R1233zd(E) or R245fa, and the second working medium is R134a, R515B or R1234ze.

[0018] Optionally, the high-temperature stage system includes a first compressor, and the low-temperature stage system includes a second compressor, both of which are equipped with compression ratio regulating valves.

[0019] Fourthly, this application provides a combined cooling and heating system, including the cascade unit provided in the third aspect of this application, and further including a hot fluid supply system, a steam supply system and a cold fluid supply system. The hot fluid supply system and the steam supply system are both connected to the high-temperature stage system and exchange heat through the condenser of the high-temperature stage system. The cold fluid supply system is connected to the low-temperature stage system and exchanges heat through the evaporator of the low-temperature stage system.

[0020] Optionally, the steam supply system includes a steam generator.

[0021] Optionally, the steam supply system may also include a booster pump connected to the steam generator.

[0022] The technical solutions provided in this application have the following advantages compared with the prior art:

[0023] The heat exchange tube provided in this embodiment has a first channel inside the tube body for containing a first working fluid. When the first working fluid flows in the first channel, it can transfer heat with the tube body. Multiple first heat exchange structures are disposed on the outer circumferential surface of the tube body. The heat exchange area can be significantly increased by the surface area of ​​the multiple first heat exchange structures, which are used for heat exchange with the second working fluid, thereby improving the heat transfer coefficient of the heat exchange tube. The first heat exchange structure includes a heat exchange body and a turbulence section connected at an angle. During the process of the second working fluid first contacting the heat exchange body and flowing along the heat exchange body to the outer circumferential surface of the tube body, a part of the second working fluid comes into contact with the turbulence section, realizing the change of flow direction, thereby generating turbulent motion at the turbulence section. While increasing the heat exchange area through the heat exchange body and the turbulence section, the flow boundary layer outside the first heat exchange structure and the tube body is destroyed by enhancing the disturbance to the second working fluid. The flow boundary layer on the tube body wall can be thinned, the distance of heat transfer from the fluid (i.e., the second working fluid) to the tube body wall is shorter, the heat transfer efficiency is higher, and the heat exchange effect of the heat exchange tube is improved. The heat transfer between the first working fluid and the second working fluid can be efficiently realized through the heat exchange tube.

[0024] The heat exchange device, cascade unit, and cogeneration system provided in this application include the aforementioned heat exchange tubes, which can achieve efficient heat transfer between working fluids. Therefore, they naturally possess the technical effects of the aforementioned heat exchange tubes. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0028] Figure 1 A partial cross-sectional view of a heat exchange tube provided in an embodiment of this application;

[0029] Figure 2 Provided for the embodiments of this application Figure 1 Enlarged detail of section A;

[0030] Figure 3This is a schematic diagram of the structure of the heat exchange device provided in the embodiments of this application;

[0031] Figure 4 A front view of the flow equalization element provided in an embodiment of this application;

[0032] Figure 5 This is a connection diagram of the cascade unit provided in an embodiment of this application;

[0033] Figure 6 This is a connection diagram of a combined cooling and heating system provided in an embodiment of this application;

[0034] Figure 7 A connection diagram of the high-temperature stage system, the hot fluid supply system, and the steam supply system provided for embodiments of this application;

[0035] Figure 8 This is a schematic diagram showing the connection between the cryogenic stage system and the cold fluid supply system provided in an embodiment of this application.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Heat exchange device; 11. Heat exchange tube; 111. Tube body; 112. Heat exchange main body; 113. Turbulence section; 114. Protrusion; 115. Second heat exchange structure; 116. Spiral groove; 12. Shell; 13. Flow equalization element; 131. Plate; 132. Flow equalization hole; 133. Clearance section; 14. Baffle plate; 15. First end cap; 16. Second end cap;

[0038] 2. High-temperature stage system; 21. First compressor; 22. First throttling element; 23. First economizer; 24. Second throttling element; 25. Condenser; 26. First refrigerant circulation loop; 261. First refrigerant output line; 262. Second refrigerant output line;

[0039] 3. Low-temperature stage system; 31. Second compressor; 32. Third throttling device; 33. Second economizer; 34. Fourth throttling device; 35. Evaporator; 36. Second refrigerant circulation loop; 361. Third refrigerant outlet line; 362. Fourth refrigerant outlet line;

[0040] 4. Hot fluid supply system; 41. First replenishment pipeline; 42. First pump; 43. Supply pipeline; 44. First valve;

[0041] 5. Steam supply system; 51. Steam generator; 52. Booster pump; 53. Second valve; 54. Second replenishment pipeline; 55. Second pump;

[0042] 6. Cold fluid supply system; 61. Inlet pipe; 62. Outlet pipe; 63. Third pump component. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0045] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0046] To address the technical problem of low heat transfer efficiency caused by the formation of a stable-thickness flow boundary layer when the heat exchange tube is a bare tube in the prior art, this application provides a heat exchange tube 11, a heat exchange device 1, a cascade unit, and a combined cooling and heating system. The heat exchange tube 11 can achieve contact and heat transfer with the first working fluid and the second working fluid respectively. Multiple first heat exchange structures are provided on the outer circumferential surface of the tube body 111, which can be used to significantly increase the heat exchange area of ​​the tube body 111. The first heat exchange structure includes a heat exchange body 112 and a turbulence section 113. While increasing the heat exchange area through the heat exchange body 112, the flow of the second working fluid can be disturbed through the turbulence section 113, thereby causing turbulent motion of the fluid (i.e., the second working fluid) on the outer circumferential surface of the tube body 111, avoiding the formation of a stable-thickness flow boundary layer, achieving the thinning of the flow boundary layer, and thus increasing the heat exchange area and frequency between the second working fluid and the outer wall of the tube body 111, thereby improving the heat transfer performance of the heat exchange tube 11.

[0047] Please see Figures 1 to 8 The first aspect of this application provides a heat exchange tube 11, including a tube body 111 and a plurality of first heat exchange structures. The tube body 111 has a first channel for containing a first working fluid. When the first working fluid flows in the first channel, it can transfer heat with the tube body 111.

[0048] Multiple first heat exchange structures are disposed on the outer circumferential surface of the tube body 111. Based on the original area of ​​the outer circumferential surface of the tube body 111, the heat exchange area can be greatly increased by the surface area of ​​multiple first heat exchange structures, which are used for heat exchange with the second working fluid, thereby improving the heat transfer coefficient of the heat exchange tube 11 and the heat exchange efficiency of the heat exchange tube 11, and enabling efficient heat transfer between the first working fluid and the second working fluid.

[0049] The first heat exchange structure includes a heat exchange body 112 and a turbulence section 113 connected at an angle. During the process of the second working fluid first contacting the heat exchange body 112 and flowing along the heat exchange body 112 to the outer circumference of the tube body 111, a portion of the second working fluid comes into contact with the turbulence section 113, thereby changing the flow direction and generating turbulent motion at the turbulence section 113. While increasing the heat exchange area through the heat exchange body 112 and the turbulence section 113, the flow boundary layer outside the first heat exchange structure and the tube body 111 is destroyed by enhancing the disturbance to the second working fluid. This can achieve the thinning of the flow boundary layer on the wall of the tube body 111. The shorter the distance of heat transfer from the fluid (i.e., the second working fluid) to the wall of the tube body 111, the higher the heat transfer efficiency. The heat exchange effect of the heat exchange tube 11 is improved, and the heat transfer between the first working fluid and the second working fluid can be efficiently realized through the heat exchange tube 11.

[0050] It should be noted that the heat exchange body 112 can be in the shape of a plate, column, or needle, and the turbulence-disrupting part 113 can also be in the shape of a plate, column, needle, or pointed structure, all of which can achieve the purpose of this application.

[0051] In some embodiments of this application, please refer to Figure 1 Multiple primary heat exchange structures are evenly arranged on the outer circumferential surface of the tube 111, which can achieve uniform heat conduction on the heat exchange tube 11, ensuring that heat is transferred more efficiently from one working medium to another, reducing heat loss and waste. At the same time, it can also reduce thermal stress caused by temperature differences inside the heat exchange tube 11, reducing the risk of damage to the heat exchange tube 11 due to excessive thermal stress.

[0052] In some embodiments of this application, please refer to Figure 1 The heat exchange body 112 extends radially along the tube body 111, maximizing the heat exchange area while avoiding interference with other heat exchange bodies 112 axially adjacent to the tube body 111. The turbulence-inducing part 113 extends axially along the tube body 111. When the second working fluid flows radially along the outer wall of the heat exchange body 112 on the tube body 111, a portion of the second working fluid can achieve near-vertical reversal through the turbulence-inducing part 113, thereby generating turbulence between two axially adjacent first heat exchange structures, enhancing the disturbance, and improving the heat exchange efficiency between the second working fluid and the outer wall of the tube body 111.

[0053] In some embodiments of this application, please refer to Figure 1 In the axial direction of the tube body 111, the turbulence-inducing part 113 is disposed on one side of the heat exchange body 112. This is because if the turbulence-inducing part 113 is disposed on both sides of the heat exchange body 112, the axial distance between two adjacent first heat exchange structures will be too small, resulting in the fluid (i.e., the second working medium) accumulating between the two first heat exchange structures having an excessively high temperature. Consequently, the temperature difference between the second working medium outside the tube body 111 and the first working medium inside the tube body 111 will be too large, reducing the heat transfer effect between them. In this application, the turbulence-inducing part 113 is disposed only on one side of the heat exchange body 112, which can generate turbulence between two adjacent first heat exchange structures and avoid the situation of excessively high temperature between two adjacent first heat exchange structures due to excessively small distance.

[0054] In some embodiments of this application, please refer to Figure 1 and Figure 2 The heat exchange body 112 has protrusions 114 on one or both sides, which can further increase the heat exchange area of ​​the first heat exchange structure. At the same time, it can also play a certain role in disturbing the fluid outside the tube 111, thereby enhancing the heat transfer effect between the second working fluid and the heat exchange tube 11.

[0055] In some embodiments of this application, please refer to Figures 1 to 2 In the radial direction from the inside to the outside of the tube body 111, the cross-sectional size of the heat exchange body 112 gradually decreases, so that the distance between two adjacent heat exchange bodies 112 gradually increases. It is preferable to set the protrusions 114 on both sides of the free end of the heat exchange body 112 (i.e. the end away from the tube body 111), which can not only increase the heat exchange area and reduce the disturbance to the fluid, but also reduce the impact of the protrusions 114 on the distance between two adjacent first heat exchange structures.

[0056] In some embodiments of this application, the protrusion 114 can be a sheet-like, block-like, or pointed structure, all of which can achieve the purpose of this application. The size of the protrusion 114 is smaller than the size of the turbulence portion 113, which can reduce the influence of the protrusion 114 on the spacing between two adjacent first heat exchange structures.

[0057] In some embodiments of this application, please refer to Figure 1 The inner circumferential surface of the tube body 111 is provided with a second heat exchange structure 115, which is used to increase the heat exchange area inside the first channel, thereby improving the heat transfer efficiency and heat exchange effect between the first working fluid and the tube body 111.

[0058] It should be noted that the second heat exchange structure 115 can be a finned structure, a textured structure, or a grooved structure disposed on the inner wall of the tube body 111, all of which can achieve the purpose of this application.

[0059] In some embodiments of this application, please refer to Figure 1 Multiple second heat exchange structures 115 are arranged in a spiral shape on the inner circumferential surface of the tube body 111 to form multiple spiral grooves 116 on the inner circumferential surface of the tube body 111. When the first working fluid flows inside the tube body 111, the flow restriction effect of the spiral grooves 116 can cause the fluid inside the tube to make an overall spiral motion, increasing fluid disturbance. At the same time, the shape resistance caused by the spiral grooves 116 can separate the flow boundary layer inside the tube body 111, thereby enhancing the heat transfer effect between the first working fluid and the tube body 111.

[0060] It should be noted that the cross-section of the second heat exchange structure 115 can be toothed, rectangular, or triangular, etc., all of which can achieve the purpose of this application.

[0061] As a specific embodiment of this application, the cross-section of the second heat exchange structure 115 is toothed, and the cross-section of the spiral groove 116 formed between two adjacent second heat exchange structures 115 is trapezoidal, making the inner wall surface of the tube 111 uneven, which can significantly increase the heat exchange area of ​​the inner wall of the tube 111. A portion of the fluid near the inner wall rotates along the spiral groove 116, while another portion flows axially along the wall surface, causing the fluid (i.e., the first working fluid) to change from laminar flow to turbulent flow or a more violently turbulent state. This change in flow state helps reduce the thickness of the flow boundary layer, making it easier for the fluid to contact the inner wall of the tube 111, thereby improving heat transfer efficiency.

[0062] Please see Figures 1 to 8 The second aspect of this application provides a heat exchange device 1, which includes the heat exchange tube 11 described in the above embodiments and a housing 12. The housing 12 has a cavity for accommodating a second working fluid. The heat exchange tube 11 is disposed inside the cavity. The first working fluid and the second working fluid undergo efficient heat transfer through the heat exchange tube 11 inside the heat exchange device 1.

[0063] In some embodiments of this application, please refer to Figure 3 A flow equalization element 13 is provided in the end cap at one end of the shell 12. Multiple heat exchange tubes 11 are arranged in parallel inside the cavity. The side of the end cap away from the cavity has a first working fluid inlet for introducing liquid first working fluid into the end cap. In the flow direction of the first working fluid, the flow equalization element 13 is arranged at the front end of multiple heat exchange tubes 11. The flow equalization element 13 can optimize the flow state and mixing effect of the first working fluid inside the end cap, and can avoid uneven distribution of the first working fluid and uneven temperature distribution among multiple heat exchange tubes 11, thereby avoiding heat transfer deterioration caused by uneven liquid distribution.

[0064] It should be noted that the shape, location and number of the flow equalization element 13 can be set according to the flow of the first working medium inside the head. As long as the flow state and mixing effect of the first working medium can be optimized, the purpose of this application can be achieved.

[0065] In some embodiments of this application, please refer to Figure 3When the heat exchanger 1 is a horizontal shell-and-tube heat exchanger, a first working fluid inlet and a first working fluid outlet are respectively provided on the first end cap 15 at one end of the shell 12. The interior of the first end cap 15 is divided into two independent cavities by a partition 14 to prevent the liquid and gaseous first working fluids from mixing in the first end cap 15. A flow equalization element 13 is provided at the lower part of the first end cap 15, and the top of the flow equalization element 13 is connected to the partition 14. The flow equalization element 13 equalizes the flow of the first working fluid inside the first end cap 15 and evenly distributes the liquid first working fluid to the multiple heat exchange tubes 11 at the bottom of the shell 12. After the gaseous second working fluid enters the shell 12, it can exchange heat and condense with the first heat exchange structure on the outer circumference of the heat exchange tubes 11. The multiple first heat exchange structures can slow down the flow rate of the gaseous second working fluid to facilitate long-term contact and sufficient heat exchange between the second working fluid and the heat exchange tubes. The condensed second working fluid falls to the bottom of the shell 12 under the action of gravity, and the liquid second working fluid can be output from the bottom of the shell 12; the gaseous first working fluid can achieve U-shaped reflux in the second end cap 16, and reflux back to the first end cap 15 through the heat exchange tube 11 at the top of the shell 12, and flow out through the first working fluid outlet at the top of the first end cap 15.

[0066] In some embodiments of this application, please refer to Figure 4 The flow equalization component 13 includes a plate 131 and a plurality of flow equalization holes 132 disposed on the plate 131. When the second working fluid passes through the plurality of flow equalization holes 132, the second working fluid can be more evenly distributed and flowed within the housing 12. The upper part of the plate 131 has a plurality of clearance portions 133, which can prevent interference with other components (such as partitions 14, etc.) assembled inside the head of the housing 12.

[0067] In some embodiments of this application, a phase mixing device is also provided at the end caps at both ends of the housing 12, which can further improve the mixing effect of the first working fluid inside the housing 12.

[0068] It should be noted that the heat exchange device 1 described above can be applied to any application scenario that requires heat exchange, such as home life, industrial production, energy and chemical industry, and can achieve efficient heat transfer between different working fluids.

[0069] Please see Figures 1 to 8The third aspect of this application provides a cascade unit, including the heat exchange device 1 described in the above embodiments, and further including a high-temperature stage system 2 and a low-temperature stage system 3. The heat exchange device 1 is an evaporator and condenser in the cascade unit. The heat exchange device 1 is connected to the high-temperature stage system 2 and the low-temperature stage system 3 respectively, so that the heat exchange device 1 is both an evaporator in the high-temperature stage system 2 and a condenser in the low-temperature stage system 3. Since the heat exchange tube 11 in the heat exchange device 1 has the advantages of high heat transfer coefficient and good heat exchange effect, it can ensure that the heat transfer between the high-temperature stage system 2 and the low-temperature stage system 3 is sufficient and efficient, which can reduce the energy loss of the cascade unit and improve the overall efficiency of the cascade unit.

[0070] In some embodiments of this application, please refer to Figure 5 In the high-temperature stage system 2, the refrigerant circulating is the first working fluid, which can flow in the first channel inside the heat exchange tube 11 and enhance the heat exchange efficiency between the first working fluid and the tube body 111 through the second heat exchange structure 115; in the low-temperature stage system 3, the refrigerant circulating is the second working fluid, which can contact the first heat exchange structure set outside the heat exchange tube 11 for heat exchange, thereby realizing the heat transfer between the high-temperature stage system 2 and the low-temperature stage system 3.

[0071] Specifically, the first working fluid is in a liquid state before flowing into the tube body 111, and the second working fluid is in a gaseous state before entering the shell 12 of the heat exchange device 1. After heat conduction is achieved through the tube body 111, the second heat exchange structure 115 and the first heat exchange structure, the first working fluid evaporates from a liquid state to a gaseous state inside the tube body 111, and the second working fluid condenses from a gaseous state to a liquid state inside the shell 12.

[0072] In traditional heat pump systems, because conventional heat pump systems use a single refrigerant and have only one refrigeration cycle, it is not only difficult to achieve a large temperature rise (such as above 120°C) between the evaporator and condenser sides, but it also leads to a huge overall compression ratio and a significant decrease in compressor efficiency. For example, when the refrigerant temperature on the evaporator side is 5°C and the refrigerant temperature on the condenser side is 132°C, if R1233zd(E) is used as the refrigerant, the compression ratio can be as high as 33.32.

[0073] To address the aforementioned issues, in some embodiments of this application, the first and second working fluids are of different types, and the evaporation temperature of the second working fluid is lower than that of the first working fluid. The high-temperature rise requirement can be met by using two independent refrigeration systems in the cascade unit, while simultaneously reducing the compression ratio within the single-stage refrigeration system. For example, when the refrigerant temperature in the evaporator 35 of the low-temperature stage system 3 is 5°C, and the refrigerant temperature in the condenser 25 of the high-temperature stage system 2 is 132°C, the single-stage compression ratio does not exceed 3 (i.e., the compression ratios of both the high-temperature stage system 2 and the low-temperature stage system 3 do not exceed 3), which can improve compressor efficiency and enhance the system energy efficiency of the cascade unit.

[0074] In some embodiments of this application, the first working fluid is R1233zd(E) (trans-1-chloro-3,3,3-trifluoropropene) or R245fa (pentafluoropropane); wherein, R1233zd(E) has a GWP (Global Warming Potential) of 1, making it a refrigerant with a low global warming potential and not depleting the ozone layer, in line with future environmental regulations; while R245fa has a GWP of 858, but due to its high heat capacity and good evaporation properties... Its properties enable it to provide excellent cooling performance over a wide temperature range, making it particularly suitable for applications requiring efficient and reliable cooling. When selecting a refrigerant, from an environmental perspective, R1233zd(E) is superior to R245fa; from an energy efficiency perspective, R1233zd(E) is 5%-7% more energy efficient than R245fa; and from a unit mass cooling / heating capacity perspective, R1233zd(E) has a 10%-15% lower heating capacity than R245fa. Therefore, from both environmental and energy efficiency perspectives, R1233zd(E) should be selected as the primary working fluid, while R245fa should be selected only when considering cooling capacity matching. This allows the high-temperature system 2 to meet different usage requirements.

[0075] In some embodiments of this application, the second working fluid is R134a (tetrafluoroethane), R515B (Honeywell R515B refrigerant), or R1234ze (1,3,3,3-tetrafluoropropylene). From an environmental perspective, the ODP (Ozone Depletion Potential) values ​​of all three are close to 0, and their GWP values, arranged from largest to smallest, are R515B > R134a > R1234ze. Furthermore, R1234ze has an extremely low GWP value (less than 1), far lower than that of traditional refrigerants, which helps reduce negative environmental impacts. In terms of energy efficiency, the system energy efficiency of R134a is more than 16% higher than that of R515B and on par with R1234ze. Considering the cooling capacity / heating capacity per unit mass, the cooling capacity of R134a is about 30% lower than that of R515 and about 25% higher than that of R1234ze. Therefore, when considering the highest energy efficiency, R134a is used as the second working fluid; when considering matching cooling capacity and not having high energy efficiency requirements, R515B is used as the second working fluid; from an environmental perspective, R1234ze is considered as the second working fluid, which can enable the cryogenic stage system 3 to meet different usage requirements.

[0076] In some embodiments of this application, from an energy efficiency perspective, the low-temperature stage system 3 should select R134a and R1233zd(E) in the high-temperature stage system 2; from an environmental protection perspective, the low-temperature stage system 3 should select R1234ze and R1233zd(E) in the high-temperature stage system 2; only when considering the matching of cooling / heating capacity and the energy efficiency requirements are not high, the low-temperature stage system 3 uses R515B and R245fa in the high-temperature stage system 2, so that the cascade unit can meet the usage requirements from different perspectives.

[0077] In some embodiments of this application, please refer to Figure 5 The high-temperature stage system 2 includes a first compressor 21, and the low-temperature stage system 3 includes a second compressor 31. Both the first compressor 21 and the second compressor 31 are equipped with compression ratio regulating valves, which can regulate the discharge pressure of the compressors (i.e., the first compressor 21 and the second compressor 31). The compression ratio of the compressors can be adjusted according to actual needs, so that they can adapt to different working conditions and load requirements. It can be used to match system working conditions, ensure that the compressors can operate in the best state under different working conditions, and ensure that the system energy efficiency is at its best.

[0078] In some preferred embodiments of this application, the compression ratio regulating valve is specifically a compression ratio regulating slide valve. The compression ratio regulating slide valve is used to match the system operating conditions and can regulate the discharge pressure of the compressor, thereby realizing the compression ratio regulation of the high temperature stage system 2 and the low temperature stage system 3, and ensuring that the system energy efficiency is at its best.

[0079] In some embodiments of this application, please refer to Figure 5 Both the first compressor 21 and the second compressor 31 are two-stage variable frequency variable pressure ratio screw compressors. Through two-stage compression, the compression ratio of a single compressor can be reduced, achieving a reasonable pressure distribution and reducing the stress on the rotor and bearings. This makes the compressor operation more stable, offering advantages such as high efficiency and energy saving, stable operation, low noise and vibration, low maintenance costs, and wide applicability. Furthermore, since both the first compressor 21 and the second compressor 31 have variable frequency functionality, the compressor's speed can be varied by adjusting the variable frequency motor, thereby regulating the compressor's discharge capacity.

[0080] In some embodiments of this application, please refer to Figure 5The high-temperature stage system 2 also includes a first throttling element 22, a first economizer 23, a second throttling element 24, a condenser 25, and a first refrigerant circulation loop 26. The first throttling element 22, the first economizer 23, the second throttling element 24, and the condenser 25 are all installed on the first refrigerant circulation loop 26. Both ends of the heat exchange device 1 are connected to the first refrigerant circulation loop 26 respectively, and are used to transport the first working fluid to the heat exchange tube 11 of the heat exchange device 1. After the first working fluid is discharged from the first compressor 21, it enters the condenser 25 and condenses into a liquid first working fluid. Then, it passes through the first throttling device 22 to achieve throttling and pressure reduction. The first working fluid after throttling and pressure reduction enters the first economizer 23. The first economizer 23 is a first flash evaporator, which can realize the rapid expansion and partial vaporization of the first working fluid. Part of the gaseous first working fluid is input into the air inlet of the first compressor 21 through the first refrigerant output pipe 261 for gas replenishment. The other part of the liquid first working fluid flows through the second refrigerant output pipe 262, passing through the second throttling device 24 and the heat exchange device 1 in sequence. After evaporating and vaporizing in the heat exchange device 1, it is then sucked into the first compressor 21 to realize the refrigerant circulation of the high-temperature stage system 2.

[0081] In some embodiments of this application, the cryogenic stage system 3 further includes a third throttling element 32, a second economizer 33, a fourth throttling element 34, an evaporator 35, and a second refrigerant circulation loop 36; the third throttling element 32, the second economizer 33, the fourth throttling element 34, and the evaporator 35 are all disposed on the second refrigerant circulation loop 36, and both ends of the heat exchange device 1 are respectively connected to the second refrigerant circulation loop 36 for conveying the second working fluid to the inside of the shell 12 of the heat exchange device 1. After the second working fluid is discharged from the second compressor 31, it enters the heat exchange device 1 and condenses into a liquid first working fluid. Then, it passes through the third throttling device 32 to achieve throttling and pressure reduction. The throttled and pressure-reduced second working fluid enters the second economizer 33, which is a second flash evaporator. It can realize the rapid expansion and partial vaporization of the second working fluid. Part of the gaseous second working fluid is input into the air inlet of the second compressor 31 through the third refrigerant output pipe 361 for gas replenishment. The other part of the liquid second working fluid flows through the fourth refrigerant output pipe 362, passing through the fourth throttling device 34 and the evaporator 35 in sequence. After evaporating and vaporizing in the evaporator 35, it is then sucked into the second compressor 31 to realize the refrigerant circulation of the low-temperature stage system 3.

[0082] It should be noted that in the above-mentioned cascade unit, the temperature rise between the evaporator 35 of the low-temperature stage system 3 and the condenser 25 of the high-temperature stage system 2 can exceed 100 degrees Celsius, and the single-stage compression ratio does not exceed 3. By optimizing the selection of refrigerant and the circulation process, a higher energy efficiency ratio can be achieved and energy consumption can be reduced.

[0083] Please see Figures 1 to 8The fourth aspect of this application provides a combined cooling and heating system, including the cascade unit described in the above embodiments, and further including a hot fluid supply system 4, a steam supply system 5 and a cold fluid supply system 6. The hot fluid supply system 4 and the steam supply system 5 are both connected to the high-temperature stage system 2 and exchange heat through the condenser 25 of the high-temperature stage system 2. The industrial waste heat of the cascade unit can be used to produce high-temperature hot fluid or high-temperature steam, realizing the transfer and reuse of energy.

[0084] The cold fluid supply system 6 is connected to the low temperature stage system 3 and exchanges heat through the evaporator 35 of the low temperature stage system 3. It can cool the cold fluid by absorbing the waste heat of the cold fluid supply system 6, and can also realize the transfer and reuse of energy.

[0085] It should be noted that cascade units can reduce energy waste and emissions during combined cooling and heating (CCHP) processes. Traditional refrigeration and heating systems often operate separately, resulting in low energy efficiency and generating significant amounts of waste heat and emissions. CCHP systems, however, combine the cooling and heating processes through cascade units, achieving energy recycling and efficient utilization, thereby reducing energy consumption and emissions.

[0086] It should be noted that the hot fluid supply system 4 can be used to supply any high-temperature (i.e., temperature above 60°C) liquid fluid substance, the steam supply system 5 can be used to supply any fluid substance that evaporates into a gaseous state, and the cold fluid supply system 6 can be used to supply any low-temperature (temperature below 20°C) liquid fluid substance. The aforementioned liquid fluid substance can specifically be water, oil, solution, etc., and the fluid substance that evaporates into a gaseous state can be water vapor or steam generated by the evaporation of other liquid substances, which is not limited here.

[0087] In some embodiments of this application, when the components of the supplied substances in the hot fluid supply system 4 and the steam supply system 5 are different, heat exchange can be carried out through two independent pipelines with the condenser 25, thereby achieving the supply of hot fluid and steam respectively.

[0088] In some embodiments of this application, please refer to Figure 6 and Figure 7 When the components of the supplied substances in the heat fluid supply system 4 and the steam supply system 5 are the same, both being the first heat exchange working fluid, they can share the same heat exchange pipeline to input the first heat exchange working fluid into the high-temperature stage condenser 25, and exchange heat with the first working fluid in the condenser 25, thereby achieving a temperature increase of the first heat exchange working fluid.

[0089] In some embodiments of this application, please refer to Figure 6 and Figure 7The heat fluid supply system includes a first replenishment line 41 connected to the condenser 25, and a first pump 42 is provided on the first replenishment line 41, which can be used to drive the flow of the first heat exchange working fluid.

[0090] In some embodiments of this application, please refer to Figure 6 and Figure 7 The steam supply system 5 includes a second replenishment line 54 connected to the condenser 25. A second pump 55 is provided on the second replenishment line 54 to drive the first heat exchange medium for generating steam into the heat exchange line of the condenser 25.

[0091] In some embodiments of this application, please refer to Figure 6 and Figure 7 The heat fluid supply system 4 includes a first valve 44, and the steam supply system 5 includes a second valve 53. When the first heat exchange medium, after its temperature rises, flows out of the condenser 25, the flow direction of the first heat exchange medium can be controlled by the first valve 44 and the second valve 53, so that it can enter the supply pipeline 43 of the heat fluid supply system 4 and / or the steam supply system 5 as needed.

[0092] In some embodiments of this application, please refer to Figure 6 and Figure 7 The steam supply system 5 includes a steam generator 51. When the first heat exchange medium is not completely vaporized in the condenser 25, steam can be further generated and transported through the steam generator 51.

[0093] In some embodiments of this application, please refer to Figure 6 and Figure 7 The steam generator 51 is connected to the second liquid replenishment pipeline 54 and can be used to store the first heat exchange medium. The steam generator 51 has a vapor-liquid separation function, which can separate the liquid first heat exchange medium from the gaseous first heat exchange medium (i.e., steam), thereby ensuring the quality and stability of the steam output from the steam generator 51.

[0094] In some embodiments of this application, please refer to Figure 6 and Figure 7 The steam supply system 5 also includes a booster pump 52 connected to the steam generator 51, which can be used to pressurize the first heat exchange medium so that the first heat exchange medium can evaporate after reaching the required temperature in the condenser 25 and / or the steam generator 51.

[0095] In some embodiments of this application, please refer to Figure 6 and Figure 7 The booster pump 52 is installed on the second replenishment pipeline 54, which can pressurize the first heat exchange medium before it enters the condenser 25.

[0096] It should be noted that when only the supply of hot fluid is required, the first valve 44 is open, the second valve 53 is closed, and the first pump 42 is in operation; when only the supply of steam is required, the first valve 44 and the first pump 42 are closed, the second valve 53 and the second pump 55 are open, and the steam generator 51 and the booster pump 52 are both in normal operation, realizing the generation and supply of steam.

[0097] In some embodiments of this application, please refer to Figure 6 and Figure 8 The cold fluid supply system 6 includes an inlet pipe 61, an outlet pipe 62, and a third pump 63. The inlet pipe 61 and the outlet pipe 62 are connected to both ends of the low-temperature stage system 3 and are used to input the second heat exchange medium into the evaporator 35, so that the second heat exchange medium and the second working medium can exchange heat inside the evaporator 35. During the heat exchange process, the temperature of the second heat exchange medium drops and flows out from the outlet pipe 62, thus realizing the supply of cold fluid.

[0098] In some embodiments of this application, the hot fluid supply system 4 is used to supply hot water below 100°C, the steam supply system 5 is used to supply steam above 100°C, and the cold fluid supply system 6 is used to supply chilled water. When the supply temperature of chilled water is below 0°C, ethylene glycol can be added to the chilled water to prevent freezing.

[0099] Please see Figures 1 to 8 The fifth aspect of this application provides a control method applied to the combined cooling and heating system described in the above embodiments to optimize system energy efficiency, comprising the following steps:

[0100] Step 1: Obtain fluid supply requirements;

[0101] Fluid supply demand includes fluid type demand and fluid temperature demand. Fluid types include cold fluids, hot fluids, and steam, which can be supplied through a combined cooling and heating system. Specifically, cold fluids can be chilled water, hot fluids can be hot water, and steam can be steam. When the temperature difference between cold and hot fluids, or between cold and steam, is large (e.g., the required temperature of chilled water is below 7°C, while the required temperature of steam is above 130°C, resulting in a temperature difference of over 120°C), the temperature difference between the second working fluid in the evaporator 35 of the low-temperature stage system 3 and the first working fluid in the condenser 25 of the high-temperature stage system 2 is also large. The compression ratio of the first compressor 21 and the second compressor 31 can be controlled by the compression ratio regulating valve, so that the low-temperature stage evaporation temperature and the high-temperature stage condensation temperature meet the fluid temperature requirements (i.e., chilled water temperature requirements, hot water temperature requirements, and steam temperature requirements, etc.). When the compression ratios of both the high-temperature stage system 2 and the low-temperature stage system 3 are close to the theoretically calculated maximum system energy efficiency compression ratio, the evaporation and condensation temperatures of the heat exchange device 1 (i.e., the evaporator and condenser) (i.e., the temperatures of the first and second working fluids in the heat exchange device 1) can be maintained within a reasonable range, further ensuring that the system's compression ratio and energy efficiency are at their optimal state.

[0102] Step 2: Adjust the compression ratio of the high-temperature stage system 2 and the low-temperature stage system 3 according to the fluid supply requirements, so that there is a first temperature difference between the refrigerant temperature in the heat exchange device 1 and the refrigerant temperature in the evaporator 35 of the low-temperature stage system 3, and a second temperature difference between the refrigerant temperature in the condenser 25 of the high-temperature stage system 2 and the refrigerant temperature in the heat exchange device 1.

[0103] In some embodiments of this application, the discharge pressure and compression ratio of the first compressor 21 and the second compressor 31 can be adjusted by a compression ratio regulating valve. The compressor discharge volume can be adjusted by the frequency conversion function of the compressor, thereby adjusting the evaporation and condensation temperature (i.e., the refrigerant temperature in the heat exchange device 1) of the heat exchange device 1.

[0104] In a specific embodiment of this application, when the low-temperature stage system 3 uses R134a as the second working fluid and the high-temperature stage system 2 uses R1233zd(E) as the first working fluid, the discharge capacity of the second compressor 31 in the low-temperature stage system 3 is Q1, and the discharge capacity of the first compressor 21 in the high-temperature stage system 2 is Q2. The enthalpy difference of the second working fluid in the low-temperature stage system 3 through the evaporator-condenser (i.e., heat exchange device 1) is h1, and the enthalpy difference of the first working fluid in the high-temperature stage system 2 through the evaporator-condenser is h2. According to the law of conservation of energy, the heat absorbed by the high-temperature stage refrigerant (i.e., the first working fluid) in the evaporator-condenser, E2 (E2 = Q2 * h2), should be equal to the heat released by the low-temperature stage refrigerant (i.e., the second working fluid) in the evaporator-condenser, E1 (E1 = Q1 * h1), and the enthalpy difference is only related to the evaporation-condensation temperature (i.e., the refrigerant temperature in the heat exchange device 1). Therefore, once the discharge capacity of the first compressor 21 and the second compressor 31 is confirmed, the enthalpy difference h1 and h2 are confirmed, and thus the evaporation and condensation temperatures are confirmed.

[0105] Since the refrigerant temperature in the evaporator 35 of the low-temperature system 3 is related to the cold fluid temperature requirement, and the refrigerant temperature in the condenser 25 of the high-temperature system 2 is related to the hot fluid or steam temperature requirement, and the refrigerant temperature in the evaporator 35 of the low-temperature system 3, the evaporation-condensation temperature, and the refrigerant temperature in the condenser 25 of the high-temperature system 2 increase sequentially, when the evaporation-condensation temperature is within a reasonable range, the difference between the first temperature difference and the second temperature difference can be avoided, thereby preventing the compression ratio of the low-temperature system 3 and / or the compression ratio of the high-temperature system 2 from being too high, which would affect the system energy efficiency.

[0106] In some embodiments of this application, the hot fluid supply system 4 is used to supply hot water, the steam supply system 5 is used to supply steam, and the cold fluid supply system 6 is used to supply chilled water; the first temperature difference = evaporation-condensation temperature - refrigerant temperature in the evaporator 35 of the low-temperature stage system 3, and the second temperature difference = refrigerant temperature in the condenser 25 of the high-temperature stage system 2 - evaporation-condensation temperature. When the evaporation-condensation temperature is in the range of 40-80℃, in order to meet the supply needs of chilled water, hot water and steam, the first temperature difference is 35℃-75℃, which can achieve a chilled water supply of -30℃-45℃; the second temperature difference is 50℃-100℃, which can achieve a hot water or steam supply of 90℃-180℃, which can meet the low-temperature cooling demand and high-temperature heating demand that are commonly present in industrial production.

[0107] In some preferred embodiments of this application, the evaporation and condensation temperature range is 50-70°C, which can maximize the system's energy efficiency.

[0108] As a specific embodiment of this application, when the refrigerant temperature in the evaporator 35 of the low-temperature stage system 3 is 5°C and the refrigerant temperature in the condenser 25 of the high-temperature stage system 2 is 132°C, the first temperature difference is 45-65°C, which can prevent the compression ratio of the low-temperature stage system 3 from being too high, thus helping to ensure the energy efficiency of the low-temperature stage system 3; the second temperature difference is 62°C-82°C, which can prevent the compression ratio of the high-temperature stage system 2 from being too high, thus helping to ensure the energy efficiency of the high-temperature stage system 2, and thereby ensuring the energy efficiency of the entire combined cooling and heating system.

[0109] In some embodiments of this application, when the system load changes, the compressor speed can be adjusted by the frequency conversion function of the first compressor 21 and the second compressor 31 to match the cooling or heating load demand; when both the system operating conditions and load change, the compressor speed can be adjusted to match the load first, and then the compression ratio can be adjusted by the compression ratio regulating valve to make the system energy efficiency the highest.

[0110] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0111] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0112] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A heat exchange tube (11), characterized in that, include: The tube (111) has a first channel inside for containing a first working fluid; The first heat exchange structure is a plurality of the first heat exchange structures, which are disposed on the outer peripheral surface of the tube body (111) for heat exchange with the second working fluid; the first heat exchange structure includes a heat exchange body (112) and a turbulence section (113) connected at an angle.

2. The heat exchange tube (11) according to claim 1, characterized in that, The heat exchange body (112) extends radially along the tube body (111), and the turbulence-disrupting part (113) extends axially along the tube body (111).

3. The heat exchange tube (11) according to claim 1, characterized in that, The heat exchange body (112) is provided with protrusions (114) on one or both sides.

4. The heat exchange tube (11) according to any one of claims 1 to 3, characterized in that, The inner circumferential surface of the tube (111) is provided with a second heat exchange structure (115) to increase the heat exchange area inside the first channel.

5. The heat exchange tube (11) according to claim 4, characterized in that, The number of the second heat exchange structure (115) is multiple, and the multiple second heat exchange structures (115) are arranged in a spiral shape on the inner circumferential surface of the tube body (111) to form multiple spiral grooves (116) on the inner circumferential surface of the tube body (111).

6. A heat exchange device (1), characterized in that, The device includes a heat exchange tube (11) as described in any one of claims 1 to 5, and a housing (12) having an interior cavity for accommodating the second working fluid, wherein the heat exchange tube (11) is disposed inside the cavity.

7. The heat exchange device (1) according to claim 6, characterized in that, A flow equalization element (13) is provided in the end cap of one end of the shell (12). A plurality of heat exchange tubes (11) are arranged in parallel inside the cavity. The end cap has a first working fluid inlet on the side away from the cavity. In the flow direction of the first working fluid, the flow equalization element (13) is provided at the front end of the plurality of heat exchange tubes (11).

8. A cascade generator unit, characterized in that, The system includes the heat exchange device (1) as described in claim 6 or 7, and further includes a high-temperature stage system (2) and a low-temperature stage system (3). The heat exchange device (1) is the evaporator-condenser in the cascade unit, and the heat exchange device (1) is connected to the high-temperature stage system (2) and the low-temperature stage system (3) respectively.

9. The cascade unit according to claim 8, characterized in that, The refrigerant circulating in the high-temperature stage system (2) is the first working fluid, and the refrigerant circulating in the low-temperature stage system (3) is the second working fluid. The first working fluid and the second working fluid are of different types.

10. The cascade unit according to claim 9, characterized in that, The first working medium is R1233zd(E) or R245fa, and the second working medium is R134a, R515B or R1234ze.

11. The cascade unit according to any one of claims 8 to 10, characterized in that, The high-temperature stage system (2) includes a first compressor (21), and the low-temperature stage system (3) includes a second compressor (31). Both the first compressor (21) and the second compressor (31) are equipped with a compression ratio regulating valve.

12. A combined cooling and heating system, characterized in that, The cascade unit as described in any one of claims 8 to 11 further includes a hot fluid supply system (4), a steam supply system (5), and a cold fluid supply system (6), wherein the hot fluid supply system (4) and the steam supply system (5) are both connected to the high-temperature stage system (2) and exchange heat through the condenser (25) of the high-temperature stage system (2), and the cold fluid supply system (6) is connected to the low-temperature stage system (3) and exchanges heat through the evaporator (35) of the low-temperature stage system (3).

13. The combined cooling and heating system according to claim 12, characterized in that, The steam supply system (5) includes a steam generator (51).

14. The combined cooling and heating system according to claim 13, characterized in that, The steam supply system (5) also includes a booster pump (52) connected to the steam generator (51).

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