A centralized heating system for towns in high-altitude and large-elevation-difference areas and a design method thereof

Abstract

The present application belongs to the technical field of urban heating, and particularly relates to a design method of a centralized heating system for a town in a high-altitude and large-elevation area. The design method of the centralized heating system for the town in the high-altitude and large-elevation area first determines a primary-side hot water flow rate through a heating system heat load and primary-side supply and return water temperature, determines a pressure-isolating heat exchange station setting position according to a highest point and lowest point elevation difference and system pressure bearing, and determines a secondary-side hot water flow rate according to an end system load and secondary-side supply and return water temperature. Then, the pressure-isolating heat exchange station and user heat exchange station system type and equipment parameters are determined according to the pressure-isolating heat exchange station setting position. Finally, the heating system parameters are determined and reviewed in combination with the pressure-isolating heat exchange station and urban heat exchange station system type and equipment parameters and primary and secondary network system type. The method is reliable in result, simple in operation, and strong in realizability, and effectively solves the design problem of the centralized heating system for the town caused by the high altitude and large elevation.

Description

Technical Field

[0001] This invention belongs to the field of urban heating technology, and specifically relates to a centralized heating system and design method for urban areas with high altitude and large elevation differences. Background Technology

[0002] With urban development, the load within the existing centralized heating area is rapidly increasing. To meet the increased heat load, it is necessary to upgrade the heat source and heating network to maximize the use of waste heat from power plants and leverage the comprehensive benefits of combined heat and power (CHP). Power plants, as the main heat source, are generally located far from the heating center, often characterized by long heating distances, wide heating ranges, and large heating areas. When power plants serve as the heat source, long-distance hot water transportation is unavoidable. Due to the long heating distances, the heating system often faces threats to system safety, such as overpressure, vaporization, and water hammer, when encountering terrain with significant elevation differences. To ensure that large-scale centralized heating projects can be implemented in cities under these circumstances, and to guarantee the safety and feasibility of the heating system, the design must find the safest and most economical solution.

[0003] Causes of overpressure: To prevent vaporization of the heating medium at higher points in the heating system, the static water pressure is higher in areas with lower elevations, making overpressure more likely. Causes of vaporization and water hammer: When the pressure at a point in the heating system is lower than the vaporization pressure of the high-temperature hot water, the hot water in the pipes will vaporize. During heating system operation, when the circulating pump malfunctions, valves close unexpectedly, or heat exchangers malfunction, the heating medium at the highest point of the heating network is prone to vaporization, leading to water hammer. The causes of overpressure, vaporization, and water hammer in heating systems are varied, but regardless of the specific situation, the result will be heating system malfunction, affecting the heating effect for residents. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide a centralized heating system and design method for towns in high-altitude areas with significant elevation differences. By setting up pressure-reducing heat exchange stations along the route, the operating pressure of the heating network is reduced, and the static pressure formed by the terrain elevation difference is distributed to each level of the network, thereby reducing the operating pressure of the network and meeting the requirements for heating over long distances with significant elevation differences. Compared with relay pump stations, this method is safer and overcomes the shortcomings of existing technologies, such as system complexity, poor feasibility, and poor stability.

[0005] The technical solution of the present invention is as follows: a centralized heating system for towns in high-altitude areas with large elevation differences, including a primary heating station, multiple pressure-reducing heat exchange stations and user heat exchange stations, wherein the primary heating station and the pressure-reducing heat exchange stations form a primary heating network through pipelines, the pressure-reducing heat exchange stations and the user heat exchange stations form a secondary heating network through pipelines, and the user heat exchange stations and users form a tertiary heating network through pipelines.

[0006] A design method for a centralized heating system in a town located in a high-altitude area with significant elevation differences includes the following steps:

[0007] S1: Determine the system type and equipment parameters of the primary heating station based on the urban heating load and the supply and return water temperatures of the heat source;

[0008] S2: Based on the elevation difference between the highest and lowest points in the heating system and the system pressure, determine the location of the pressure-reducing heat exchange station while ensuring that the system does not exceed the pressure limit.

[0009] S3: Based on the primary network system type, the heating first station system type and equipment parameters determined in step S1, and the location of the pressure-reducing heat exchange station determined in step S2, determine the pressure-reducing heat exchange station system type and equipment parameters.

[0010] S4: Determine the secondary hot water flow rate under design conditions based on the terminal system load and the secondary side supply and return water temperatures;

[0011] S5: Determine the user's heat exchange station system type and equipment parameters based on the secondary network system type, the location of the pressure-reducing heat exchange station determined in step S2, and the secondary side hot water flow rate determined in step S4.

[0012] S6: Based on the aforementioned steps S1 to S5, complete the design of the heating system's pressure-bearing and pressure-isolation heat exchange station quantity, pressure-isolation heat exchanger parameters, and urban heat exchanger parameters.

[0013] S7: Determine whether the heat balance and hydraulic balance of the heating system in step S6 meet the actual operation and standard requirements. If not, adjust the system parameters of the pressure-reducing heat exchange station and user heat exchange station, and optimize the pipeline network layout until the requirements are met, and finally complete the heating system design.

[0014] In step S1, determining the system type and equipment parameters of the primary heating station includes determining the hot water flow rate and pump head of the primary heating station, specifically:

[0015] (1) The hot water flow rate G at the primary heating station is determined by the following formula:

[0016]

[0017] In the formula: Q is the urban heating load, kW; t g The primary hot water supply temperature is ℃; t h Δt is the primary hot water return temperature, in °C; Δt is the primary hot water supply and return temperature difference, in °C.

[0018] (2) The head H of the water pump at the primary heating station is determined by the following formula:

[0019] H=R×l (2)

[0020] In the formula: H is the head of the water pump at the first heating station, Pa; R is the specific friction resistance of the main line, taken as 30-70 Pa / m; l is the length of the main line at the first heating station, m.

[0021] The steps for determining the location of the pressure-reducing heat exchange station in step 2 are as follows:

[0022] S21: First, determine the maximum elevation difference Δh in the heating system using the following formula:

[0023] Δh=h1-h2 (3)

[0024] In the formula: Δh is the maximum elevation difference in the heating system, m; h1 is the altitude of the highest point, m; h2 is the altitude of the lowest point, m;

[0025] S22: Next, determine the maximum pressure P of the heating system. The specific process is as follows: According to the Urban Heating Pipeline Design Standard (CJJ / T34-2022), the design pressure of urban heating pipelines with thermal power plants and boiler rooms as heat sources is less than or equal to 2.5 MPa. For low-temperature hot water pipelines from user heating stations or small heat sources directly supplied to heat-using buildings, applicable to general heating, air conditioning and domestic hot water systems, the temperature is not higher than 95°C and the pressure is not higher than 1.6 MPa. Based on this, determine the maximum pressure P of the heating system as 1.6 MPa or P = 2.5 MPa.

[0026] S23: Finally, determine the location and number of pressure-reducing heat exchange stations, specifically:

[0027] When the maximum pressure of the heating system is P = 1.6 MPa, one pressure-reducing heat exchange station should be set up within every 100-meter elevation difference. The number of pressure-reducing heat exchange stations, N, is calculated using the following formula:

[0028]

[0029] Where: N is the number of pressure-reducing heat exchange stations in the heating system, in units; Δh is the maximum elevation difference in the heating system, in meters;

[0030] Similarly, when the maximum pressure of the heating system P = 2.5 MPa, one pressure-reducing heat exchange station should be set up within every 200-meter elevation difference. The number of pressure-reducing heat exchange stations N is calculated using the following formula:

[0031]

[0032] In the formula: N is the number of pressure-reducing heat exchange stations in the heating system, in units; ΔH is the maximum elevation difference in the terrain of the heating system, in meters.

[0033] In step S3, the system type and equipment parameters of the pressure-reducing heat exchange station are determined. The steps are as follows:

[0034] S31: First, determine the heat load Q1 of a single pressure-reducing heat exchange station, calculated using the following formula:

[0035] Q1 = q1 × A1 × 10 -3 (6)

[0036] In the formula: Q1 is the heat load of a single pressure-reducing heat exchange station, in kW; q1 is the heating index, in W / m². 2 A1 represents the heating area provided by a single pressure-reducing heat exchange station, in m². 2 ;

[0037] S32: Next, determine the heat exchange capacity of the heat exchanger in the pressure diaphragm heat exchange station based on the heat load Q1 of a single pressure diaphragm heat exchange station;

[0038] S33: Next, based on the heat load Q1 of a single pressure-reducing heat exchange station and the supply and return water temperatures of the pressure-reducing heat exchange station, determine the flow rate G1 of the pressure-reducing heat exchange station using the following formula:

[0039]

[0040] In the formula: Q1 is the heat load of a single pressure-reducing heat exchange station, in kW; t g1 The hot water supply temperature on the pressure-retaining side is in °C; t h1 Δt1 is the hot water return temperature on the pressure diaphragm side, in °C; Δt1 is the hot water supply and return temperature difference on the pressure diaphragm side, in °C.

[0041] S34: Finally, determine the pump head H1 of the pressure-reducing heat exchange station by calculating the following formula:

[0042] H1=R×l1 (8)

[0043] In the formula: H1 is the pump head of the pressure-reducing heat exchange station, Pa; R is the specific friction resistance of the main line, taken as 30-70 Pa / m; l1 is the length of the main line of the pressure-reducing heat exchange station, m.

[0044] In step S4, the secondary hot water flow rate GG is calculated using equation (9):

[0045]

[0046] In the formula: QQ is the load of the terminal system, in kW; t gg The secondary hot water supply temperature is expressed in °C; t hh Δtt represents the secondary hot water return temperature, in °C; Δtt represents the temperature difference between the secondary hot water supply and return, in °C.

[0047] In step S5, the system type and equipment parameters of the user's heat exchange station are determined. The steps are as follows:

[0048] S51: First, determine the heat load Q2 of the user's heat exchange station, which is calculated using the following formula:

[0049] Q2 = q2 × A2 × 10 -3 (10)

[0050] In the formula: Q2 is the heat load of the user's heat exchange station, kW; q1 is the heat index of the heating terminal, W / m². 2 A2 represents the heating area provided by a single user heat exchange station, in m². 2 ;

[0051] S52: Next, select the heat exchanger for the user's heat exchange station based on the user's heat load Q2;

[0052] S53: Finally, based on the user's heat exchange station heat load Q2 and the supply and return water temperatures of the user's heat exchange station, determine the user's heat exchange station flow rate G2 using the following formula:

[0053]

[0054] In the formula: Q2 is the heat load of the user's heat exchange station, in kW; t g2 The hot water supply temperature for the user's heat exchange station is in °C; t h2 Δt2 is the hot water return temperature of the user's heat exchange station, in °C; Δt2 is the temperature difference between the hot water supply and return water of the user's heat exchange station, in °C.

[0055] S54: Finally, determine the pump head H2 of the user's heat exchange station by calculating the following formula:

[0056] H2=R×l2 (12)

[0057] In the formula: H2 is the pump head of the user's heat exchange station, Pa; R is the specific friction resistance of the main line, taken as 30-70 Pa / m; l2 is the length of the main line of the user's heat exchange station, m.

[0058] Step 6 involves determining whether the thermal and hydraulic balance of the heating system meets the requirements of actual operation and regulatory standards. The specific process is as follows:

[0059] (1) Based on the urban heating load Q, the heat load Q1 of the pressure-reducing heat exchange station, and the heat load Q2 of the user heat exchange station determined in steps S1, S3, and S5, the heat balance is verified by the following formula:

[0060] Q = Q1 = Q2 (13)

[0061] (2) Based on the primary hot water flow rate G, the pressure-reducing heat exchange station flow rate G1, and the user heat exchange station flow rate G2 determined in steps S1, S3, and S5 above, the hydraulic balance is verified by the following formula:

[0062] H = S × G 2 (14)

[0063] H1 = S1 × G1 2 (15)

[0064] H2=S2×G2 2 (16)

[0065] Where: S is the pipeline resistance coefficient of the primary heating station, Pa / (m) 3 / h) 2 S1 represents the resistance coefficient of the main pipeline of the pressure-reducing heat exchange station, in Pa / (m). 3 / h) 2 S2 represents the resistance of the main pipeline of the user's heat exchange station, in Pa / (m). 3 / h) 2 .

[0066] The technical advantages of this invention are as follows: 1. The design method for urban centralized heating systems in high-altitude areas with large elevation differences can quickly complete the design of the heating system's pressure bearing capacity, the number of pressure-reducing heat exchange stations, the parameters of the pressure-reducing heat exchangers, and the parameters of the urban heat exchangers. The design method is simple, safe, and reliable, and can effectively reduce problems such as system overpressure, vaporization, and water hammer caused by high altitude and large elevation differences; 2. This invention isolates the long-distance pipeline network and the primary pipeline network into two independent systems through pressure-reducing heat exchange stations, which is beneficial to the operation and regulation of the urban heating system. This can greatly reduce the possibility of failure, prevent problems before they occur, and ensure the safe, stable, and efficient operation of the unit during the operation period.

[0067] The following will provide further explanation in conjunction with the accompanying drawings. Attached Figure Description

[0068] Figure 1 This is a flowchart illustrating a design method for a centralized heating system in a high-altitude, high-difference urban area, according to an embodiment of the present invention.

[0069] Figure 2 This is a schematic diagram of a centralized heating system for towns in high-altitude areas with large elevation differences, according to the present invention. Detailed Implementation

[0070] Example 1

[0071] like Figure 2 As shown, a centralized heating system for towns in high-altitude areas with large elevation differences includes a primary heating station, multiple pressure-reducing heat exchange stations, and user heat exchange stations. The primary heating station and the pressure-reducing heat exchange stations form a primary heating network through pipelines. The pressure-reducing heat exchange stations and the user heat exchange stations form a secondary heating network through pipelines. The user heat exchange stations and users form a tertiary heating network through pipelines.

[0072] In practical use, this invention isolates the long-distance pipeline network and the primary pipeline network into two independent systems through the pressure-isolation heat exchange station, which is beneficial to the operation and regulation of the urban heating system. This can greatly reduce the possibility of failure, prevent problems before they occur, and ensure the safe, stable and efficient operation of the unit during the operation period.

[0073] Example 2

[0074] like Figure 1 As shown, a design method for a centralized heating system in a town located in a high-altitude area with a large elevation difference includes the following steps:

[0075] S1: Determine the system type and equipment parameters of the primary heating station based on the urban heating load and the supply and return water temperatures of the heat source;

[0076] S2: Based on the elevation difference between the highest and lowest points in the heating system and the system pressure, determine the location of the pressure-reducing heat exchange station while ensuring that the system does not exceed the pressure limit.

[0077] S3: Based on the primary network system type, the heating first station system type and equipment parameters determined in step S1, and the location of the pressure-reducing heat exchange station determined in step S2, determine the pressure-reducing heat exchange station system type and equipment parameters.

[0078] S4: Determine the secondary hot water flow rate under design conditions based on the terminal system load and the secondary side supply and return water temperatures;

[0079] S5: Determine the user's heat exchange station system type and equipment parameters based on the secondary network system type, the location of the pressure-reducing heat exchange station determined in step S2, and the secondary side hot water flow rate determined in step S4.

[0080] S6: Based on the aforementioned steps S1 to S5, complete the design of the heating system's pressure-bearing and pressure-isolation heat exchange station quantity, pressure-isolation heat exchanger parameters, and urban heat exchanger parameters.

[0081] S7: Determine whether the heat balance and hydraulic balance of the heating system in step S6 meet the actual operation and standard requirements. If not, adjust the system parameters of the pressure-reducing heat exchange station and user heat exchange station, and optimize the pipeline network layout until the requirements are met, and finally complete the heating system design.

[0082] In step S1, determining the system type and equipment parameters of the primary heating station includes determining the hot water flow rate and pump head of the primary heating station, specifically:

[0083] (1) The hot water flow rate G at the primary heating station is determined by the following formula:

[0084]

[0085] In the formula: Q is the urban heating load, kW; t g The primary hot water supply temperature is ℃; t h Δt is the primary hot water return temperature, in °C; Δt is the primary hot water supply and return temperature difference, in °C.

[0086] (2) The head H of the water pump at the primary heating station is determined by the following formula:

[0087] H=R×l (2)

[0088] In the formula: H is the head of the water pump at the first heating station, Pa; R is the specific friction resistance of the main line, taken as 30-70 Pa / m; l is the length of the main line at the first heating station, m.

[0089] The steps for determining the location of the pressure-reducing heat exchange station in step 2 are as follows:

[0090] S21: First, determine the maximum elevation difference Δh in the heating system using the following formula:

[0091] Δh=h1-h2 (3)

[0092] In the formula: Δh is the maximum elevation difference in the heating system, m; h1 is the altitude of the highest point, m; h2 is the altitude of the lowest point, m;

[0093] S22: Next, determine the maximum pressure P of the heating system. The specific process is as follows: According to the design standard of urban heating pipeline network (CJJ / T 34-2022), the design pressure of urban heating pipeline network with thermal power plants and boiler rooms as heat sources is less than or equal to 2.5 MPa. For low-temperature hot water pipeline network from user heating stations or small heat sources directly supplied to heat-using buildings, applicable to general heating, air conditioning and domestic hot water systems, the temperature is not higher than 95°C and the pressure is not higher than 1.6 MPa. Based on this, determine the maximum pressure P of the heating system as 1.6 MPa or P = 2.5 MPa.

[0094] S23: Finally, determine the location and number of pressure-reducing heat exchange stations, specifically:

[0095] When the maximum pressure of the heating system is P = 1.6 MPa, one pressure-reducing heat exchange station should be set up within every 100-meter elevation difference. The number of pressure-reducing heat exchange stations, N, is calculated using the following formula:

[0096]

[0097] Where: N is the number of pressure-reducing heat exchange stations in the heating system, in units; Δh is the maximum elevation difference in the heating system, in meters;

[0098] Similarly, when the maximum pressure of the heating system P = 2.5 MPa, one pressure-reducing heat exchange station should be set up within every 200-meter elevation difference. The number of pressure-reducing heat exchange stations N is calculated using the following formula:

[0099]

[0100] In the formula: N is the number of pressure-reducing heat exchange stations in the heating system, in units; ΔH is the maximum elevation difference in the terrain of the heating system, in meters.

[0101] In step S3, the system type and equipment parameters of the pressure-reducing heat exchange station are determined. The steps are as follows:

[0102] S31: First, determine the heat load Q1 of a single pressure-reducing heat exchange station, calculated using the following formula:

[0103] Q1 = q1 × A1 × 10 -3 (6)

[0104] In the formula: Q1 is the heat load of a single pressure-reducing heat exchange station, in kW; q1 is the heating index, in W / m². 2 A1 represents the heating area provided by a single pressure-reducing heat exchange station, in m². 2 ;

[0105] S32: Next, determine the heat exchange capacity of the heat exchanger in the pressure diaphragm heat exchange station based on the heat load Q1 of a single pressure diaphragm heat exchange station;

[0106] S33: Next, based on the heat load Q1 of a single pressure-reducing heat exchange station and the supply and return water temperatures of the pressure-reducing heat exchange station, determine the flow rate G1 of the pressure-reducing heat exchange station using the following formula:

[0107]

[0108] In the formula: Q1 is the heat load of a single pressure-reducing heat exchange station, in kW; t g1 The hot water supply temperature on the pressure-retaining side is in °C; t h1 Δt1 is the hot water return temperature on the pressure diaphragm side, in °C; Δt1 is the hot water supply and return temperature difference on the pressure diaphragm side, in °C.

[0109] S34: Finally, determine the pump head H1 of the pressure-reducing heat exchange station by calculating the following formula:

[0110] H1=R×l1 (8)

[0111] In the formula: H1 is the pump head of the pressure-reducing heat exchange station, Pa; R is the specific friction resistance of the main line, taken as 30-70 Pa / m; l1 is the length of the main line of the pressure-reducing heat exchange station, m.

[0112] In step S4, the secondary hot water flow rate GG is calculated using equation (9):

[0113]

[0114] In the formula: QQ is the load of the terminal system, in kW; t gg The secondary hot water supply temperature is expressed in °C; t hh Δtt represents the secondary hot water return temperature, in °C; Δtt represents the temperature difference between the secondary hot water supply and return, in °C.

[0115] In step S5, the system type and equipment parameters of the user's heat exchange station are determined. The steps are as follows:

[0116] S51: First, determine the heat load Q2 of the user's heat exchange station, which is calculated using the following formula:

[0117] Q2 = q2 × A2 × 10 -3 (10)

[0118] In the formula: Q2 is the heat load of the user's heat exchange station, kW; q1 is the heat index of the heating terminal, W / m². 2 A2 represents the heating area provided by a single user heat exchange station, in m². 2 ;

[0119] S52: Next, select the heat exchanger for the user's heat exchange station based on the user's heat load Q2;

[0120] S53: Finally, based on the user's heat exchange station heat load Q2 and the supply and return water temperatures of the user's heat exchange station, determine the user's heat exchange station flow rate G2 using the following formula:

[0121]

[0122] In the formula: Q2 is the heat load of the user's heat exchange station, in kW; t g2 The hot water supply temperature for the user's heat exchange station is in °C; t h2 Δt2 is the hot water return temperature of the user's heat exchange station, in °C; Δt2 is the temperature difference between the hot water supply and return water of the user's heat exchange station, in °C.

[0123] S54: Finally, determine the pump head H2 of the user's heat exchange station by calculating the following formula:

[0124] H2=R×l2 (12)

[0125] In the formula: H2 is the pump head of the user's heat exchange station, Pa; R is the specific friction resistance of the main line, taken as 30-70 Pa / m; l2 is the length of the main line of the user's heat exchange station, m.

[0126] Step 6 involves determining whether the thermal and hydraulic balance of the heating system meets the requirements of actual operation and regulatory standards. The specific process is as follows:

[0127] (1) Based on the urban heating load Q, the heat load Q1 of the pressure-reducing heat exchange station, and the heat load Q2 of the user heat exchange station determined in steps S1, S3, and S5, the heat balance is verified by the following formula:

[0128] Q = Q1 = Q2 (13)

[0129] (2) Based on the primary hot water flow rate G, the pressure-reducing heat exchange station flow rate G1, and the user heat exchange station flow rate G2 determined in steps S1, S3, and S5 above, the hydraulic balance is verified by the following formula:

[0130] H = S × G 2 (14)

[0131] H1 = S1 × G1 2 (15)

[0132] H2=S2×G2 2 (16)

[0133] Where: S is the pipeline resistance coefficient of the primary heating station, Pa / (m) 3 / h) 2 S1 represents the resistance coefficient of the main pipeline of the pressure-reducing heat exchange station, in Pa / (m). 3 / h) 2 S2 represents the resistance of the main pipeline of the user's heat exchange station, in Pa / (m). 3 / h) 2 .

[0134] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A design method for a centralized heating system in a town located in a high-altitude area with a large elevation difference, characterized in that: Design a centralized heating system for towns in high-altitude areas with large elevation differences. The system includes a primary heating station, multiple pressure-reducing heat exchange stations, and user heat exchange stations. A primary heating network is formed between the primary heating station and the pressure-reducing heat exchange stations via pipelines. A secondary heating network is formed between the pressure-reducing heat exchange stations and the user heat exchange stations via pipelines. A tertiary heating network is formed between the user heat exchange stations and the users via pipelines. The design method includes the following steps: S1: Determine the system type and equipment parameters of the primary heating station based on the urban heating load and the supply and return water temperatures of the heat source; S2: Based on the elevation difference between the highest and lowest points in the heating system and the system pressure, determine the location of the pressure-reducing heat exchange station while ensuring that the system does not exceed the pressure limit. S3: Based on the primary network system type, the heating first station system type and equipment parameters determined in step S1, and the location of the pressure-reducing heat exchange station determined in step S2, determine the pressure-reducing heat exchange station system type and equipment parameters. S4: Determine the secondary hot water flow rate under design conditions based on the terminal system load and the secondary side supply and return water temperatures; S5: Determine the user's heat exchange station system type and equipment parameters based on the secondary network system type, the location of the pressure-reducing heat exchange station determined in step S2, and the secondary side hot water flow rate determined in step S4. S6: Based on the aforementioned steps S1~S5, complete the design of the heating system's pressure-bearing and pressure-isolation heat exchange station quantity, pressure-isolation heat exchanger parameters, and urban heat exchanger parameters. S7: Determine whether the heat balance and hydraulic balance of the heating system in step S6 meet the actual operation and standard requirements. If not, adjust the system parameters of the pressure-reducing heat exchange station and user heat exchange station, and optimize the pipeline network layout until the requirements are met, and finally complete the heating system design.

2. The design method for a centralized heating system in a high-altitude area with a large elevation difference according to claim 1, characterized in that: In step S1, determining the system type and equipment parameters of the primary heating station includes determining the hot water flow rate and pump head of the primary heating station, specifically: (1) The hot water flow rate G at the primary heating station is determined by the following formula: （1） In the formula: For urban heating load, kW; The primary hot water supply temperature is ℃; The primary side hot water return temperature is ℃; The temperature difference between the primary hot water supply and return water is expressed in °C. (2) Head of the water pump at the first heating station It is determined by the following formula: （2） In the formula: The head of the water pump at the first heating station is measured in Pa. For the main line, the specific friction resistance should be 30-70. ; The length of the main line of the first heating station is in meters (m).

3. The design method for a centralized heating system in a high-altitude area with a large elevation difference according to claim 1, characterized in that: The steps for determining the location of the pressure-reducing heat exchange station in step S2 are as follows: S21: First, determine the maximum elevation difference in the terrain within the heating system. Calculated using the following formula: （3） In the formula: The maximum elevation difference in the terrain within the heating system is expressed in meters (m). The altitude of the highest point is in meters (m). The lowest point's elevation is in meters (m). S22: Next, determine the maximum pressure that the heating system can withstand. The specific process is as follows: According to the Urban Heating Pipeline Design Standard (CJJ / T34-2022), the design pressure of urban heating pipelines using thermal power plants and boiler rooms as heat sources is less than or equal to 2.5 MPa. Low-temperature hot water pipelines from user heating stations or small heat sources directly supplying heat to heat-using buildings are applicable to general heating, air conditioning, and domestic hot water systems, with temperatures not exceeding 95°C and pressures not exceeding 1.6 MPa. Based on this, the maximum pressure of the heating system is determined. or ; S23: Finally, determine the location and number of pressure-reducing heat exchange stations, specifically: When the heating system is under maximum pressure In this case, one pressure-reducing heat exchange station should be set up within every 100-meter elevation difference. The number of pressure-reducing heat exchange stations, N, is calculated using the following formula: （4） In the formula: N is the number of pressure-reducing heat exchange stations in the heating system, in units; The maximum elevation difference in the terrain within the heating system is expressed in meters (m). Similarly, when the heating system reaches its maximum pressure In this case, one pressure-reducing heat exchange station should be set up within every 200-meter elevation difference. The number of pressure-reducing heat exchange stations, N, is calculated using the following formula: （5） In the formula: N is the number of pressure-reducing heat exchange stations in the heating system, in units; The maximum elevation difference in the heating system is expressed in meters (m).

4. The design method for a centralized heating system in a high-altitude area with a large elevation difference according to claim 1, characterized in that: In step S3, the system type and equipment parameters of the pressure-reducing heat exchange station are determined. The steps are as follows: S31: First, determine the heat load of a single pressure-reducing heat exchange station. Calculated using the following formula: （6） In the formula: For the heat load of a single pressure-reducing heat exchange station, ; For heating heat index, ; The heating area provided by a single pressure-reducing heat exchange station. ; S32: Secondly, based on the heat load of a single pressure-reducing heat exchange station Determine the heat exchange capacity of the heat exchanger in the pressure-reducing heat exchange station; S33: Next, based on the heat load of a single pressure-reducing heat exchange station The flow rate of the pressure-reducing heat exchange station is determined by the supply and return water temperatures. Calculated using the following formula: （7） In the formula: The heat load of a single pressure-reducing heat exchange station is kW; The hot water supply temperature on the pressure-isolating side is ℃; The temperature of the hot water return on the pressure isolation side is ℃; The temperature difference between the hot water supply and return on the pressure isolation side is ℃; S34: Final determination of the pump head for the pressure-reducing heat exchange station Calculated using the following formula: （8） In the formula: The pump head of the pressure-reducing heat exchange station is given in Pa. For the main line, the specific friction resistance should be 30-70. ; The length of the main pipeline of the pressure-reducing heat exchange station is in meters (m).

5. The design method for a centralized heating system in a high-altitude area with a large elevation difference according to claim 1, characterized in that: In step S4, the secondary hot water flow rate GG is calculated using equation (9): （9） In the formula: For the end-system load, kW; The secondary hot water supply temperature is in °C. The secondary hot water return temperature is in °C. The temperature difference between the secondary hot water supply and return water is expressed in °C.

6. The design method for a centralized heating system in a high-altitude area with a large elevation difference according to claim 1, characterized in that: In step S5, the system type and equipment parameters of the user's heat exchange station are determined. The steps are as follows: S51: First, determine the heat load of the user's heat exchange station. Calculated using the following formula: （10） In the formula: For the heat load of the user's heat exchange station, ; For the heat index at the end of the heating system, ; The heating area provided by a single user heat exchange station. ; S52: Secondly, based on the heat load of the user's heat exchange station Select heat exchangers for user heat exchange stations; S53: Finally, based on the heat load of the user's heat exchange station The supply and return water temperatures of the user's heat exchange station determine the flow rate of the user's heat exchange station. Calculated using the following formula: （11） In the formula: Heat load of the user's heat exchange station, kW; The hot water supply temperature for the user's heat exchange station is in °C. The hot water return temperature of the user's heat exchange station, in °C; The temperature difference between the hot water supply and return water at the user's heat exchange station, in °C; S54: Final determination of the pump head at the user's heat exchange station Calculated using the following formula: （12） In the formula: The pump head of the user's heat exchange station is measured in Pa. For the main line, the specific friction resistance should be 30-70. ; The length of the main line of the user's heat exchange station is in meters (m).

7. The design method for a centralized heating system in a high-altitude area with a large elevation difference according to claim 1, characterized in that: In step S6, it is determined whether the thermal balance and hydraulic balance of the heating system meet the requirements of actual operation and standard specifications. The specific process is as follows: (1) Urban heating load determined according to steps S1, S3 and S5 Heat load of pressure-reducing heat exchange station Heat load of user heat exchange station The thermal balance is verified by the following formula: （13） (2) The primary hot water flow rate determined according to the aforementioned steps S1, S3, and S5. Flow rate of pressure-reducing heat exchange station User heat exchange station flow The hydraulic balance is verified by the following formula: （14） （15） （16） In the formula: The resistance value of the pipeline at the first heating station. ; This refers to the resistance of the main pipeline of the pressure-reducing heat exchange station. ; For the resistance of the main pipeline of the user's heat exchange station, .

Images