Heat collection field, solar power station and design method of heat collection field

Abstract

The invention relates to the technical field of solar thermal power generation, and discloses a heat collection field, a solar power station and a design method of the heat collection field. The heat collection field comprises a liquid inlet pipe, a plurality of heat collection pipes and a liquid outlet pipe, the two ends of each heat collection pipe communicate with the liquid inlet pipe and the liquid outlet pipe correspondingly, the liquid inlet pipe comprises a first end, a plurality of first connecting openings and a second end which are sequentially distributed in the axial direction, each first connecting opening communicates with one heat collection pipe, and the inner diameters of all the heat collection pipes are consistent; the liquid inlet pipe is configured in the mode that the inner diameter of the liquid inlet pipe is gradually reduced from the first end to the second end. The inner diameter of the liquid inlet pipe is gradually reduced from the first end where the heat exchange medium flows in to the second end where the heat exchange medium flows out, the problem that flow loss is generated when the liquid inlet pipe flows through each heat collection pipe, and consequently flow is not uniform is solved, the reduction of the flow is matched with the reduction of the inner diameter, and the heat exchange efficiency is improved. The flow velocity uniformity degree of all positions in the liquid inlet pipe is improved, the flow uniformity degree in each heat collection pipe is improved, and the heat collection effect is improved.

Description

Technical Field

[0001] This invention relates to the field of solar thermal power generation technology, specifically to a design method for a solar collector field, a solar power plant, and a solar collector field. Background Technology

[0002] In solar thermal power plants, parabolic trough collectors absorb solar energy and heat the heat transfer medium through multiple parallel collector loops. Uniform flow distribution across each collector loop is crucial for ensuring the efficient and safe operation of the collector system. However, some related technologies suffer from uneven flow distribution in their collector systems. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a heat collection field that can improve the uniformity of flow rate.

[0004] The present invention also proposes a solar power plant having the above-mentioned heat collection field and a design method for the above-mentioned heat collection field.

[0005] According to a first aspect of the present invention, a heat collection field includes an inlet pipe, a plurality of heat collection tubes, and an outlet pipe: the two ends of the heat collection tubes are respectively connected to the inlet pipe and the outlet pipe, the inlet pipe includes a first end, a plurality of first connection ports and a second end distributed sequentially along the axial direction, each first connection port being connected to one heat collection tube, the heat exchange medium entering the inlet pipe from the first end, flowing through the heat collection tube through the first connection port and then flowing out from the outlet pipe, the inner diameter of each heat collection tube being the same; the inlet pipe is configured such that the inner diameter of the inlet pipe gradually decreases from the first end to the second end.

[0006] The heat collection field according to embodiments of the present invention has at least the following beneficial effects: the inlet pipe is configured such that its inner diameter gradually decreases from the first end into which the heat exchange medium flows to the second end into which the heat exchange medium flows out, thus solving the problem of flow loss and uneven flow caused by the inlet pipe flowing through each heat collection tube. The reduction in flow rate matches the reduction in inner diameter, improving the uniformity of flow velocity at various locations within the inlet pipe, thereby improving the uniformity of flow velocity of the heat exchange medium flowing from each first connection port to each heat collection tube, and further improving the uniformity of flow rate within each heat collection tube, thus improving the heat collection effect.

[0007] According to some embodiments of the present invention, the inlet pipe includes a plurality of first sub-pipes connected sequentially along the axial direction. From the first end to the second end, the inner diameter of the first sub-pipe located downstream is smaller than the inner diameter of the first sub-pipe located upstream.

[0008] According to some embodiments of the present invention, the inner diameter of each first sub-tube is constant, and at least one first sub-tube is provided with a plurality of first connection ports along the axial direction.

[0009] According to some embodiments of the present invention, the liquid outlet pipe includes a plurality of second sub-pipes connected sequentially along the axial direction, the heat collection field includes a plurality of equivalent groups, each of the equivalent groups includes a plurality of heat collection pipes, one end of each heat collection pipe in each of the equivalent groups is connected to the same first sub-pipe, and the other end is connected to the same second sub-pipe.

[0010] According to some embodiments of the present invention, the inner wall of the inlet pipe is tapered, and the inner diameter of the inlet pipe decreases linearly from the first end to the second end.

[0011] According to some embodiments of the present invention, the inlet pipe and the outlet pipe are arranged side by side, and multiple heat collection pipes are arranged at intervals along the length direction of the inlet pipe. The outlet pipe includes a third end, multiple second connection ports and a fourth end distributed sequentially along the axial direction. Each second connection port is connected to one heat collection pipe. The heat exchange medium flows out of the outlet pipe from the fourth end, and the fourth end is far away from the first end relative to the third end.

[0012] According to some embodiments of the present invention, the inner diameter of the outlet tube gradually increases from the third end to the fourth end.

[0013] According to some embodiments of the present invention, the outlet pipe includes a plurality of second sub-pipes connected sequentially along the axial direction. From the third end to the fourth end, the inner diameter of the downstream second sub-pipe is greater than the inner diameter of the upstream second sub-pipe. Alternatively, the outlet pipe is tapered, and the inner diameter of the outlet pipe increases linearly and continuously from the third end to the fourth end.

[0014] According to some embodiments of the present invention, the heat collection tubes are configured such that all the heat collection tubes have the same length and the interval between any two adjacent heat collection tubes is equal.

[0015] According to the design method of the heat collection field of the second aspect embodiment of the present invention, a heat collection field as described in any one of the first aspect embodiments is established, and the inner diameter of the liquid inlet pipe is designed. The inner diameter design of the liquid inlet pipe includes the following steps: setting the total flow rate of the liquid inlet pipe, calculating the flow loss generated when the heat exchange medium flows in the liquid inlet pipe and passes through each of the heat collection pipes; calculating the flow rate change rate of the heat exchange medium flowing from the first end to the second end based on the degree of flow loss; setting the flow velocity in the liquid inlet pipe to be constant, calculating the rate of change of the inner diameter of the liquid inlet pipe following the flow rate change rate in the liquid inlet pipe based on the flow rate change rate, and obtaining the theoretical change of the inner diameter of the liquid inlet pipe when the flow velocity is constant; and designing the actual inner diameter of the liquid inlet pipe based on the theoretical change of the inner diameter of the liquid inlet pipe.

[0016] The design method of the heat collection field according to the embodiments of the present invention has at least the following beneficial effects: by first establishing a theoretical model with an inlet pipe and a heat collection pipe, and then setting the total flow rate of the inlet pipe, the flow loss generated during the flow of the heat exchange medium can be better calculated, thereby calculating the theoretical change of the inner diameter through the flow rate change rate, solving the problem that the change of the inner diameter cannot well balance the flow loss, improving the flow uniformity brought about by the change of the inner diameter, and enabling the actual inner diameter of the inlet pipe to better achieve the flow balance in the heat collection field.

[0017] According to some embodiments of the present invention, the step of designing the actual inner diameter of the inlet pipe based on the theoretical change includes: after obtaining the theoretical change of the inner diameter of the inlet pipe, selecting to manufacture a tapered inlet pipe so that the change of the inner diameter of the inlet pipe is equal to the theoretical change; or selecting to manufacture a stepped inlet pipe so that the inlet pipe includes a plurality of first sub-pipes, the plurality of first sub-pipes being connected sequentially along the axial direction, from the first end to the second end, the inner diameter of the downstream first sub-pipe is smaller than the inner diameter of the upstream first sub-pipe, and the average rate of change of the inner diameter of the first sub-pipe is equal to the theoretical change.

[0018] According to some embodiments of the present invention, when the stepped inlet pipe is selected for manufacture, the inner diameter of the first sub-pipe conforms to the inner diameter requirements of the national standard pipe.

[0019] According to some embodiments of the present invention, the outlet pipe includes a third end and a fourth end distributed sequentially along the axial direction. The heat exchange medium flows out of the outlet pipe from the fourth end. The flow velocity in the outlet pipe is set to be constant. The rate of change of the inner diameter of the outlet pipe following the flow rate in the outlet pipe is calculated, and the theoretical change of the inner diameter of the outlet pipe when the flow velocity is constant is obtained.

[0020] According to some embodiments of the present invention, the design method of the heat collection field further includes a verification step: after obtaining the theoretical change of the inner diameter of the inlet pipe when the flow rate is constant, a simulation tool is used to establish a calculation model of the heat collection field, so that the change of the inner diameter of the inlet pipe in the calculation model is equal to the theoretical change. A set total flow rate is input into the first end of the calculation model, the flow rate data at each first connection port is recorded, and compared with a preset flow rate range. If the flow rate data at the first connection port is greater than the preset flow rate range, the inner diameter of the inlet pipe at the current first connection port is increased; if the flow rate data at the first connection port is less than the preset flow rate range, the inner diameter of the inlet pipe at the current first connection port is decreased.

[0021] A solar power plant according to a third aspect of the present invention includes a collector field as described in any one of the first aspect embodiments.

[0022] The solar power plant according to embodiments of the present invention has at least the following beneficial effects: In the first aspect embodiment, the uniform flow rate of the heat collection tubes in the heat collection field can improve the overall efficiency, stability, and safety of the solar power plant system. Uniform flow rate ensures that each heat collection tube is heated evenly, preventing some tubes from overheating due to excessively low flow rate or insufficient heat exchange due to excessively high flow rate, thereby maximizing the photothermal conversion efficiency.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the heat collection field in the first embodiment of the present invention; Figure 2 This is a schematic diagram of the heat collection field in the second embodiment of the present invention; Figure 3 This is a flowchart illustrating a method for designing a heat collection field in one embodiment of the present invention.

[0025] Reference numerals: collector field 100, liquid inlet pipe 101, collector tube 102, liquid outlet pipe 103, first end 104, first connection port 105, second end 106, first sub-tube 107, second sub-tube 108, equivalent group 109, third end 110, fourth end 111, second connection port 112. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0028] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0029] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0030] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] In existing heat collection fields, the diameter of the inlet pipe is usually fixed. However, the heat exchange medium is affected by various factors as it flows from the inlet to the outlet. These factors include flow loss as it flows through each heat collection tube. Therefore, the flow rate decreases as it moves further away from the inlet. Since the pipe diameter remains constant, the flow velocity also decreases, resulting in different flow velocities towards the heat collection tubes. This causes unequal flow velocities and flow rates at different locations within the heat collection field (because the pipe diameter is usually kept constant). Consequently, some loops may experience overheating or even solidification of the heat exchange medium due to insufficient flow, while other loops may experience unnecessary pressure drops and pump power consumption due to excessive flow, affecting the thermal efficiency and economy of the heat collection field.

[0032] This application proposes a heat collection field 100 that can improve the uniformity of flow, thereby improving thermal efficiency and economy.

[0033] refer to Figure 1 and Figure 2According to a first aspect embodiment of the present invention, the heat collection field 100 includes an inlet pipe 101, multiple heat collection tubes 102, and an outlet pipe 103. The two ends of the heat collection tubes 102 are respectively connected to the inlet pipe 101 and the outlet pipe 103. The inlet pipe 101 includes a first end 104, multiple first connection ports 105, and a second end 106 distributed sequentially along the axial direction. Each first connection port 105 is connected to a heat collection tube 102. The heat exchange medium enters the inlet pipe 101 from the first end 104, flows through the heat collection tubes 102 through the first connection ports 105, and then flows out from the outlet pipe 103. The inner diameter of each heat collection tube 102 is the same. The inlet pipe 101 is configured such that the inner diameter of the inlet pipe 101 gradually decreases from the first end 104 to the second end 106. By configuring the inlet pipe 101 with a gradually decreasing inner diameter from the first end 104 where the heat exchange medium flows in to the second end 106 where the heat exchange medium flows out, the problem of flow loss and uneven flow caused by the inlet pipe 101 flowing through each heat collector tube 102 is solved. The reduction in flow rate matches the reduction in inner diameter, improving the uniformity of flow velocity at various locations within the inlet pipe 101. This, in turn, improves the uniformity of flow velocity of the heat exchange medium flowing from each first connection port 105 to each heat collector tube 102, thereby improving the uniformity of flow rate within each heat collector tube 102 and enhancing the heat collection effect. Flow rate and velocity are directly proportional, while flow rate and inner diameter are inversely proportional. Therefore, if the inner diameter remains constant, both flow rate and velocity will gradually decrease. By configuring the inner diameter to gradually decrease, the variation in flow velocity can be reduced, thus balancing the flow rate and velocity within each heat collector tube 102 as much as possible.

[0034] It should be noted that the inner diameter of the inlet pipe 101 gradually decreases, including... Figure 1 The gradient descent structure shown also includes Figure 2 The structure shown is a linearly decreasing structure.

[0035] It should be noted that, Figure 1 and Figure 2 The hollow arrows indicate the flow direction of the heat exchange medium. In some embodiments of the present invention, the heat exchange medium can be water, heat transfer oil, or molten salt. Molten salt refers to the melt formed by the melting of inorganic salts at high temperatures. It is composed of metal cations and non-metal anions, has a high specific heat capacity, and can store and transfer a large amount of heat energy. Furthermore, molten salt has low viscosity and high thermal conductivity, good fluidity in the liquid state, and high heat transfer efficiency. Using molten salt as a heat exchange medium can effectively improve the thermal efficiency of the heat collection field 100.

[0036] refer to Figure 1In some embodiments of the present invention, the inlet pipe 101 includes a plurality of first sub-pipes 107 connected sequentially along the axial direction, from the first end 104 to the second end 106. The inner diameter of the downstream first sub-pipe 107 is smaller than that of the upstream first sub-pipe 107. By using multiple first sub-pipes 107, the finished pipe can be used as the first sub-pipe 107, and the inlet pipe 101 can be formed by welding or other means. This reduces the processing difficulty and cost of the inlet pipe 101, and maintains the characteristic of gradually decreasing inner diameter, thus improving flow balance while reducing processing difficulty and cost. It should be noted that if the first sub-pipe 107 is like... Figure 2 The diameter variation shown is configured such that the maximum inner diameter of the first sub-pipe 107 located downstream is smaller than the minimum inner diameter of the first sub-pipe 107 located upstream, thus meeting the requirements for flow balance.

[0037] refer to Figure 1 In some embodiments of the present invention, the inner diameter of each first sub-tube 107 is constant, and at least one first sub-tube 107 is provided with a plurality of first connection ports 105 along the axial direction. First sub-tubes 107 with constant inner diameters are more readily available from finished tubes, eliminating the need for additional manufacturing and further reducing processing difficulty and costs. The multiple first connection ports 105 along the axial direction of the first sub-tube 107 allow for the connection of multiple collector tubes 102, reducing the final number of first sub-tubes 107 required and lowering processing costs. It should be noted that the flow velocity and flow rate within collector tubes 102 connected to the same first sub-tube 107 may deviate, but due to the close proximity, the flow loss is not significant. Using first sub-tubes 107 with the same inner diameter can significantly reduce processing costs with minimal reduction in precision. In some embodiments, a first sub-tube 107 with an optimal inner diameter can also be provided between every two adjacent collector tubes 102, ensuring that the flow velocities of the collector tubes 102 upstream and downstream of the first sub-tube 107 are the same.

[0038] refer to Figure 1In some embodiments of the present invention, the liquid outlet pipe 103 includes a plurality of second sub-pipes 108, which are connected sequentially along the axial direction. The heat collection field 100 includes a plurality of equivalent groups 109, each equivalent group 109 including a plurality of heat collection pipes 102. One end of the heat collection pipe 102 in each equivalent group 109 is connected to the same first sub-pipe 107, and the other end is connected to the same second sub-pipe 108. Using a plurality of second sub-pipes 108, the finished pipe can be used as the second sub-pipe 108 and combined by welding or other means to form the liquid outlet pipe 103, which can also reduce the processing difficulty and processing cost of the liquid outlet pipe 103. The two ends of the plurality of heat collection pipes 102 in an equivalent group 109 are connected to the same first sub-pipe 107 and second sub-pipe 108, which can make the flow velocities of these heat collection pipes 102 relatively close. Under the premise of reducing a small amount of precision, the processing cost is greatly reduced, and the length of the heat collection pipe 102 can be made as... Figure 1 As shown, the heat collection tube 102 can also maintain a straight design, ensuring that the values ​​remain equal.

[0039] refer to Figure 2 In some embodiments of the present invention, the inner wall of the liquid inlet pipe 101 is tapered, and the inner diameter of the liquid inlet pipe 101 decreases linearly from the first end 104 to the second end 106. The heat collection pipes 102 of the heat collection field 100 are typically numerous and closely arranged, thus the trend of flow loss tends to change linearly. Therefore, the linearly decreasing inner diameter can better match the linearly decreasing flow rate, thereby making the flow velocity from each first connection port 105 to the heat collection pipe 102 more balanced, further improving the flow uniformity and thermal efficiency.

[0040] refer to Figure 1 and Figure 2 In some embodiments of the present invention, the inlet pipe 101 and the outlet pipe 103 are arranged side by side, and multiple heat collection pipes 102 are arranged at intervals along the length direction of the inlet pipe 101. The outlet pipe 103 includes a third end 110, multiple second connection ports 112 and a fourth end 111 arranged sequentially along the axial direction. Each second connection port 112 is connected to a heat collection pipe 102. The heat exchange medium flows out of the outlet pipe 103 from the fourth end 111. The fourth end 111 is farther away from the first end 104 than the third end 110. This arrangement ensures that the fluid flow length of all heat collection loops is basically the same. For example, the heat collection tube 102, which is closer to the first end 104 where the heat exchange medium flows in, has a shorter flow in the inlet pipe 101 but a longer flow in the outlet pipe 103. Conversely, the heat collection tube 102, which is closer to the fourth end 111 where the heat exchange medium flows out, has a longer flow in the inlet pipe 101 but a shorter flow in the outlet pipe 103. Overall, the total flow length of both is similar, thereby reducing flow unevenness caused by flow differences and improving flow uniformity.

[0041] refer to Figure 3In some embodiments of the present invention, the inner diameter of the outlet pipe 103 gradually increases from the third end 110 to the fourth end 111. The flow rate change of the outlet pipe 103 is based on the same principle as the flow rate change of the inlet pipe 101, but the trend is opposite. From the third end 110 to the fourth end 111, the heat exchange medium from each heat collection tube 102 continuously flows into the outlet pipe 103, thus gradually increasing the flow rate. Therefore, the inner diameter of the outlet pipe 103 gradually increases, making the flow velocity at each position in the outlet pipe 103 eventually more balanced. This further improves the flow velocity balance at each position in the heat collection field 100, avoids safety problems caused by excessively high or low flow velocities at individual positions, and improves safety and thermal efficiency.

[0042] refer to Figure 1 and Figure 2 In some embodiments of the present invention, the outlet pipe 103 includes a plurality of second sub-pipes 108, which are connected sequentially along the axial direction from the third end 110 to the fourth end 111. The inner diameter of the downstream second sub-pipe 108 is larger than that of the upstream second sub-pipe 108. Alternatively, the outlet pipe 103 is tapered, with its inner diameter increasing linearly from the third end 110 to the fourth end 111. The stepped outlet pipe 103 can reduce manufacturing costs and processing difficulty, while the tapered outlet pipe 103 can further improve flow uniformity. Any structure of the outlet pipe 103 can be selected according to requirements.

[0043] refer to Figure 1 and Figure 2 In some embodiments of the present invention, the heat collection tubes 102 are configured such that all heat collection tubes 102 have equal lengths and the spacing between any two adjacent heat collection tubes 102 is equal. Equal lengths of each heat collection tube 102 facilitate the calculation of flow loss caused by the first connection port 105, while equal spacing between two heat collection tubes 102 ensures a linear trend in the final flow rate. This allows for better calculation of the theoretical inner diameters of the inlet pipe 101 and outlet pipe 103 based on the flow rate change trend, and enables the corresponding manufacture of the actual inlet pipe 101 and outlet pipe 103.

[0044] refer to Figure 2According to the design method of the heat collection field of the second aspect embodiment of the present invention, a heat collection field 100 of any one of the first aspect embodiments is established, and the inner diameter of the liquid inlet pipe 101 is designed. The design of the inner diameter of the liquid inlet pipe 101 includes the following steps: setting the total flow rate of the liquid inlet pipe 101, and calculating the flow loss generated when the heat exchange medium flows in the liquid inlet pipe 101 and passes through each heat collection pipe 102. Calculating the flow rate change rate of the heat exchange medium flowing from the first end 104 to the second end 106 based on the degree of flow loss. Setting the flow velocity in the liquid inlet pipe 101 to be constant, and calculating the rate of change of the inner diameter of the liquid inlet pipe 101 following the flow rate change rate based on the flow rate change rate, thereby obtaining the theoretical change of the inner diameter of the liquid inlet pipe 101 when the flow velocity is constant; and designing the actual inner diameter of the liquid inlet pipe 101 based on the theoretical change of the inner diameter of the liquid inlet pipe 101. By first establishing a theoretical model with inlet pipe 101 and heat collection pipe 102, and then setting the total flow rate of inlet pipe 101, the flow loss generated during the flow of heat exchange medium can be calculated better. Thus, the theoretical change of inner diameter can be calculated through the flow rate change rate, solving the problem that the change of inner diameter cannot well balance the flow loss, improving the flow uniformity caused by the change of inner diameter, and enabling the actual inner diameter of inlet pipe 101 to better achieve flow balance within heat collection field 100.

[0045] It should be noted that there is a specific relationship between flow rate, flow velocity, and inner diameter. For example, in some embodiments, the volumetric flow rate is Q, the inner diameter of the inlet pipe 101 is D, and the flow velocity of the heat exchange medium in the inlet pipe 101 is v. According to the formula Q = π × (D / 2)² × v, it can be known that when v is constant, the inner diameter D of the inlet pipe 101 has a certain functional relationship with the flow rate Q. The theoretical change value can then be calculated based on the functional relationship.

[0046] In some embodiments of the present invention, the step of designing the actual inner diameter of the inlet pipe 101 based on the theoretical change includes: after obtaining the theoretical change of the inner diameter of the inlet pipe 101, selecting to manufacture a tapered inlet pipe 101 so that the change of the inner diameter of the inlet pipe 101 is equal to the theoretical change; or, selecting to manufacture a stepped inlet pipe 101 so that the inlet pipe 101 includes a plurality of first sub-pipes 107, the plurality of first sub-pipes 107 being connected sequentially along the axial direction from the first end 104 to the second end 106, the inner diameter of the downstream first sub-pipe 107 being smaller than the inner diameter of the upstream first sub-pipe 107, and the average rate of change of the inner diameter of the first sub-pipe 107 being equal to the theoretical change. After obtaining the theoretical change value, one can choose to design a stepped inlet pipe 101 with lower processing difficulty and cost, or a conical inlet pipe 101 with better flow uniformity, depending on the requirements. When manufacturing a stepped shape, using the average change rate of the inner diameter of the first sub-pipe 107 as the manufacturing benchmark value can maximize the flow uniformity while maintaining the stepped tubular structure. For example, when the first sub-pipe 107 is connected to three heat collection pipes 102, and the theoretical change of the inner diameter of the first sub-pipe 107 is from the first end 104 to the second end 106, the inner diameter of the first sub-pipe 107 shrinks from 30mm to 20mm. In this case, the first sub-pipe 107 can be manufactured as a through pipe with a diameter of (30+20) / 2=25mm. It should be noted that in some embodiments, the outlet pipe 103 can also be manufactured into a conical or stepped structure according to production requirements.

[0047] In some embodiments of the present invention, when a stepped inlet pipe 101 is selected for manufacturing, the inner diameter of the first sub-pipe 107 conforms to the inner diameter requirements of national standard pipes. The stepped reducer constructed using national standard pipes allows for seamless connection between its components and other pipes, valves, flanges, and other parts that meet the same standards on the market. This greatly simplifies design selection, procurement, and inventory management, avoids supply chain complexity and project delay risks caused by the use of non-standard parts, and also improves construction efficiency and reduces overall costs. Specifically, in some embodiments, seamless steel pipes according to national standard GB / T 8162-2018 can be used to manufacture the first sub-pipe 107 or the second sub-pipe 108. The average change rate of the inner diameter of the first sub-pipe 107 is calculated, and then a national standard inner diameter steel pipe with the closest average change rate is selected to manufacture the actual first sub-pipe 107.

[0048] In some embodiments of the present invention, the outlet pipe 103 includes a third end 110 and a fourth end 111 distributed sequentially along the axial direction. The heat exchange medium flows out of the outlet pipe 103 from the fourth end 111. The flow velocity within the outlet pipe 103 is set to be constant. The rate of change of the inner diameter of the outlet pipe 103 following the flow rate within the outlet pipe 103 is calculated, yielding the theoretical change in the inner diameter of the outlet pipe 103 when the flow velocity is constant. The calculation principle for the change in the inner diameter of the outlet pipe 103 is the same as that for the change in the inner diameter of the inlet pipe 101, also calculated based on the relationship between flow velocity, flow rate, and inner diameter. Obtaining the theoretical change in the inner diameter of the outlet pipe 103 allows for better manufacturing of the actual outlet pipe 103, thereby improving the uniformity of the flow rate within the outlet pipe 103.

[0049] In some embodiments of the present invention, the design method of the heat collection field further includes a verification step: after obtaining the theoretical change in the inner diameter of the inlet pipe 101 when the flow rate is constant, a calculation model of the heat collection field 100 is established using simulation tools, so that the change in the inner diameter of the inlet pipe 101 in the calculation model is equal to the theoretical change. A set total flow rate is input into the first end 104 of the calculation model, and the flow rate data at each first connection port 105 is recorded and compared with a preset flow rate range. If the flow rate data at the first connection port 105 is greater than the preset flow rate range, the inner diameter of the inlet pipe 101 at the current first connection port 105 is increased; if the flow rate data at the first connection port 105 is less than the preset flow rate range, the inner diameter of the inlet pipe 101 at the current first connection port 105 is decreased. Using simulation tools to establish a model can further verify the theoretical calculation, and multiple parameters such as fluid friction resistance, water pressure change, and pressure difference can be comprehensively tested in the model to improve the actual flow uniformity. Furthermore, the inner diameter of the inlet pipe 101 can be adjusted according to the parameters at each first connection port 105 to make it tend to balance. It should be noted that flow velocity, water pressure, flow rate, and the temperature of the inlet pipe 101 and outlet pipe 103 are all parameters that reflect the uniformity of the flow of the heat exchange medium in the heat collection field 100. They are all related to each other. In some embodiments of this application, the flow velocity data can be tested and adjusted, or the inner diameter of the inlet pipe 101 or outlet pipe 103 can be adjusted by testing the water pressure data or flow rate data.

[0050] It should be noted that in some embodiments, simulation tools can be simulation software such as Flowmaster, Apros, AspenHYSYS, MATLAB, and Simulink.

[0051] According to a third aspect embodiment of the present invention, a solar power plant includes a collector field 100 as described in any of the first aspect embodiments. In the collector field 100 of the first aspect embodiment, the flow rate of the collector tubes 102 is uniform, which can improve the overall efficiency, stability, and safety of the solar power plant system. Uniform flow rate ensures that each collector tube 102 is heated evenly, avoiding overheating in some pipes due to excessively low flow rate or insufficient heat exchange due to excessively high flow rate, thereby maximizing the photothermal conversion efficiency.

[0052] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A heat collection field, characterized in that, Includes an inlet pipe, multiple collector tubes, and an outlet pipe: The two ends of the heat collection tube are respectively connected to the inlet pipe and the outlet pipe. The inlet pipe includes a first end, a plurality of first connection ports and a second end distributed in sequence along the axial direction. Each first connection port is connected to one heat collection tube. The heat exchange medium enters the inlet pipe from the first end, flows through the heat collection tube through the first connection port and then flows out from the outlet pipe. The inner diameter of each heat collection tube is the same. The inlet pipe is configured such that its inner diameter gradually decreases from the first end to the second end.

2. The heat collection field according to claim 1, characterized in that, The inlet pipe includes a plurality of first sub-pipes connected sequentially along the axial direction. From the first end to the second end, the inner diameter of the first sub-pipe located downstream is smaller than the inner diameter of the first sub-pipe located upstream.

3. The heat collection field according to claim 2, characterized in that, The inner diameter of each of the first sub-tubes is constant, and at least one of the first sub-tubes is provided with a plurality of first connection ports along the axial direction.

4. The heat collection field according to claim 3, characterized in that, The liquid outlet pipe includes multiple second sub-pipes, which are connected sequentially along the axial direction. The heat collection field includes multiple equivalent groups, and each equivalent group includes multiple heat collection pipes. One end of each heat collection pipe in each equivalent group is connected to the same first sub-pipe, and the other end is connected to the same second sub-pipe.

5. The heat collection field according to claim 1, characterized in that, The inner wall of the inlet pipe is tapered, and the inner diameter of the inlet pipe decreases linearly from the first end to the second end.

6. The heat collection field according to claim 1, characterized in that, The inlet pipe and the outlet pipe are arranged side by side, and multiple heat collection tubes are arranged at intervals along the length of the inlet pipe. The outlet pipe includes a third end, multiple second connection ports and a fourth end distributed sequentially along the axial direction. Each second connection port is connected to one heat collection tube. The heat exchange medium flows out of the outlet pipe from the fourth end, which is farther away from the first end relative to the third end.

7. The heat collection field according to claim 6, characterized in that, From the third end to the fourth end, the inner diameter of the outlet pipe gradually increases.

8. The heat collection field according to claim 7, characterized in that, The outlet pipe includes multiple second sub-pipes, which are connected sequentially along the axial direction from the third end to the fourth end. The inner diameter of the downstream second sub-pipe is larger than that of the upstream second sub-pipe. Alternatively, the outlet pipe is tapered, and the inner diameter of the outlet pipe increases linearly and continuously from the third end to the fourth end.

9. The heat collection field according to claim 6, characterized in that, The heat collection tubes are configured such that all the heat collection tubes are of equal length and the interval between any two adjacent heat collection tubes is equal.

10. A method for designing a thermal collector field, characterized in that, To establish a heat collection field according to any one of claims 1 to 9, the inner diameter of the liquid inlet pipe is designed, and the design of the inner diameter of the liquid inlet pipe includes the following steps: Set the total flow rate of the inlet pipe and calculate the flow loss of the heat exchange medium when it flows through each of the heat collector tubes. The rate of change of flow of the heat exchange medium flowing from the first end to the second end is calculated based on the degree of flow loss. The flow velocity in the inlet pipe is set to be constant. Based on the flow rate change rate, the inner diameter of the inlet pipe is calculated as a function of the flow rate in the inlet pipe, and the theoretical change of the inner diameter of the inlet pipe when the flow velocity is constant is obtained. The actual inner diameter of the inlet pipe is designed based on the theoretical variation of the inlet pipe's inner diameter.

11. The design method for a thermal collector field according to claim 10, characterized in that, The step of designing the actual inner diameter of the inlet pipe based on the theoretical change includes: after obtaining the theoretical change of the inner diameter of the inlet pipe, selecting to manufacture a tapered inlet pipe so that the change of the inner diameter of the inlet pipe is equal to the theoretical change; or selecting to manufacture a stepped inlet pipe so that the inlet pipe includes multiple first sub-pipes, the multiple first sub-pipes are connected sequentially along the axial direction, from the first end to the second end, the inner diameter of the downstream first sub-pipe is smaller than the inner diameter of the upstream first sub-pipe, and the average rate of change of the inner diameter of the first sub-pipe is equal to the theoretical change.

12. The design method for a thermal collector field according to claim 11, characterized in that, When the stepped inlet pipe is selected for manufacturing, the inner diameter of the first sub-pipe meets the requirements of the national standard pipe inner diameter.

13. The method for designing a thermal collector field according to claim 10, characterized in that, The outlet pipe includes a third end and a fourth end distributed sequentially along the axial direction. The heat exchange medium flows out of the outlet pipe from the fourth end. The flow velocity in the outlet pipe is set to be constant. The rate of change of the inner diameter of the outlet pipe following the flow rate in the outlet pipe is calculated, and the theoretical change of the inner diameter of the outlet pipe when the flow velocity is constant is obtained.

14. The design method for a thermal collector field according to any one of claims 10 to 13, characterized in that, The design method of the heat collection field also includes a verification process: after obtaining the theoretical change of the inner diameter of the inlet pipe when the flow rate is constant, a simulation tool is used to establish a calculation model of the heat collection field, so that the change of the inner diameter of the inlet pipe in the calculation model is equal to the theoretical change. A set total flow rate is input into the first end of the calculation model, the flow rate data at each first connection port is recorded, and compared with a preset flow rate range. If the flow rate data at the first connection port is greater than the preset flow rate range, the inner diameter of the inlet pipe at the current first connection port is increased; if the flow rate data at the first connection port is less than the preset flow rate range, the inner diameter of the inlet pipe at the current first connection port is decreased.

15. A solar power station, characterized in that, The heat collection field includes any one of claims 1 to 9.

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