Method and system for improving heating capacity by utilizing soil heat storage

Abstract

The invention relates to the technical field of heating and heat supply, and discloses a method and system for improving the heating and heat supply capacity through soil heat storage, and the method comprises the steps that thermal power generating unit data are collected, and whether the heating steam extraction capacity meets the load requirement or not is judged; when the heating steam extraction capacity meets the load requirement, heat is stored through the soil heat accumulator; when the heating steam extraction capacity is insufficient, heat is released through the soil heat accumulator; heat storage and release parameters are calculated according to thermal power generating unit data, the heat release rate is dynamically adjusted, and heating load fluctuation is stabilized. According to the method, thermal power generating unit data are collected, the heating steam extraction capacity is judged, and the heat storage and release process is dynamically adjusted; through the sleeve structure and the fin design of the soil heat accumulator, the heat accumulation and heat release efficiency is improved; and in combination with calculation of heat storage and release parameters and soil heat storage amount, accurate monitoring and optimization of heat utilization are achieved, energy loss is reduced, the reliability and economical efficiency of the system are improved, and therefore efficient and stable operation of the heating system is achieved, and the requirements of deep peak regulation and extremely cold periods are met.

Description

Technical Field

[0001] The present invention relates to the field of heating technology, and in particular to a method and system for improving heating capacity by utilizing soil heat storage. Background Art

[0002] With the continuous increase in the installed capacity of new energy power generation such as solar energy and wind energy, traditional thermal power generation has gradually changed from the main role of power generation to supply guarantee and peak load regulation. At present, urban residents in my country still rely mainly on heating steam extraction from thermal power plants. As thermal power units frequently participate in the peak load regulation of the power grid, the heating steam extraction capacity of the units fluctuates accordingly. With the continuous increase in the capacity of new energy grid-connected power generation, the depth of participation of thermal power units in peak load regulation has gradually increased, and the frequency has gradually increased. With the advancement of urbanization, the demand for urban heating has continued to increase, and the technology for thermal power plants to improve their heating capacity has continued to develop. Common technologies include: medium and low pressure connecting pipe steam extraction heating transformation, high back pressure / low vacuum heating transformation, low pressure optical axis heating transformation, heat pump heating transformation, low pressure cylinder zero output heating transformation, turbine bypass heating transformation, etc.

[0003] The above heating steam extraction technologies are all modified on the steam source side, aiming to improve the heating steam extraction capacity of the unit under low power load conditions by changing the steam-water process of thermal power generation. Therefore, the heating capacity of the above technologies is limited by the unit's own technical parameters and grid dispatch, and cannot break through the limitations of the unit's own thermal system. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is that the heating capacity of the existing technology is limited by the unit's own technical parameters and power grid scheduling, and cannot break through the unit's own thermal system limitations.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a method for improving heating capacity by utilizing soil heat storage, comprising: collecting data of thermal power units to determine whether the heating steam extraction capacity meets the load demand; when the heating steam extraction capacity meets the load demand, storing heat through the soil heat accumulator; when the heating steam extraction capacity is insufficient, releasing heat through the soil heat accumulator; calculating heat storage and release parameters according to the thermal power unit data, dynamically adjusting the heat release rate, and smoothing the heating load fluctuations.

[0007] As a preferred solution of the method of utilizing soil heat storage to improve heating capacity described in the present invention, the thermal power unit data includes the inlet and outlet temperatures, flow rate, soil temperature of the heat network circulating water, and the heating steam extraction flow rate and pressure of the thermal power unit.

[0008] As a preferred solution of the method of utilizing soil heat storage to improve heating capacity described in the present invention, the soil heat accumulator has a casing structure inside, fins for enhancing heat exchange are arranged on the outer surface, and thermocouple temperature measuring points are evenly arranged around it.

[0009] As a preferred solution of the method of utilizing soil heat storage to improve heating capacity described in the present invention, the heat storage by the soil heat accumulator includes that hot water flows into the inside of the casing during heat storage, exchanges heat with the surrounding low-temperature soil, and then enters the heat network return water.

[0010] As a preferred solution of the method of utilizing soil heat storage to improve heating capacity described in the present invention, the heat release through the soil heat accumulator includes that when releasing heat, the return water of the heat network enters the soil heat accumulator, bringing the heat in the soil to the water supply of the heat network.

[0011] As a preferred solution of the method for improving heating capacity by using soil heat storage described in the present invention, the heat storage and heat release parameters include heat storage, heat release, heat storage efficiency and soil heat storage. The heat storage and heat release are calculated according to the inlet and outlet temperatures of the heat network circulating water at the soil heat accumulator and the circulating water flow rate. The heat storage is expressed as:

[0012]

[0013] Among them, Q 储1 is the heat storage; C p Specific heat capacity of circulating water in the heat network; ρ is the circulating water density; V is the circulating water flow rate; T2 is the circulating water inlet temperature; T1 is the circulating water outlet temperature; t1 is the start time of heat storage; t2 is the end time of heat storage; the heat release is expressed as:

[0014]

[0015] Among them, Q 放1 is the heat release; t3 is the start time of heat release; t4 is the end time of heat release; the ratio of heat release to heat storage is the heat storage efficiency, which is expressed as:

[0016]

[0017] Where η is the heat storage efficiency.

[0018] As a preferred solution of the method for improving heating capacity by using soil heat storage according to the present invention, the soil heat storage is calculated according to the measured heat exchange of the soil, and is expressed as:

[0019] Q 储2 =ρ 土壤 C p，土壤 ∫∫∫ΔTdv

[0020] Among them, Q储2 Stores heat in the soil; 土壤 is soil density; C p，土壤 is the specific heat capacity of soil; ΔT is the change in soil temperature; v represents the volume of soil.

[0021] A system for improving heating capacity by utilizing soil heat storage using any of the methods described in the present invention, wherein: a collection module collects data of thermal power units to determine whether the heating steam extraction capacity meets the load demand; a heat storage module stores heat through a soil heat accumulator when the heating steam extraction capacity meets the load demand; a heat release module releases heat through a soil heat accumulator when the heating steam extraction capacity is insufficient; and an adjustment module calculates heat storage and release parameters based on the thermal power unit data, dynamically adjusts the heat release rate, and smoothes heating load fluctuations.

[0022] A computer device comprises: a memory and a processor; the memory stores a computer program, comprising: the steps of implementing any one of the methods of the present invention when the processor executes the computer program.

[0023] A computer-readable storage medium stores a computer program, comprising: when the computer program is executed by a processor, the steps of implementing any one of the methods of the present invention are implemented.

[0024] The beneficial effects of the present invention are as follows: the method of the present invention collects data of thermal power units and determines the heating steam extraction capacity, dynamically adjusts the heat storage and release processes, realizes intelligent heat distribution, and effectively alleviates the impact of heating load fluctuations on heating stability; through the casing structure and fin design of the soil heat accumulator, the efficiency of heat storage and heat release is improved to ensure efficient operation of the system; combined with the calculation of heat storage and heat release parameters and soil heat storage capacity, heat utilization is accurately monitored and optimized, energy loss is reduced, and system reliability and economy are improved, thereby realizing efficient and stable operation of the heating system and meeting the needs of deep peak regulation and extreme cold periods. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0026] Figure 1 An overall flow chart of a method for improving heating capacity by utilizing soil heat storage provided by an embodiment of the present invention;

[0027] Figure 2 A conventional thermal power unit heating flow chart of a method for improving heating capacity by utilizing soil heat storage provided by an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of a system for improving heating capacity by using soil, which is a method for improving heating capacity by using soil heat storage, provided by one embodiment of the present invention;

[0029] Figure 4 A schematic diagram of a heat storage process structure (heat storage process) of a single soil heat accumulator in a method for improving heating capacity by using soil heat storage provided by an embodiment of the present invention;

[0030] Figure 5 A schematic diagram of a single soil heat accumulator structure (heat release process) of a method for improving heating capacity by utilizing soil heat storage provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0032] Example 1, reference Figure 1-Figure 5 , which is an embodiment of the present invention, provides a method for improving heating capacity by using soil heat storage, comprising:

[0033] S1: Collect data from thermal power units to determine whether the heating steam extraction capacity meets the load demand.

[0034] S2: When the heating steam extraction capacity meets the load demand, the heat is stored in the soil heat storage tank.

[0035] S3: When the heating steam extraction capacity is insufficient, heat is released through the soil heat storage.

[0036] S4: Calculate the heat storage and release parameters based on the data of the thermal power units, dynamically adjust the heat release rate, and smooth out heating load fluctuations.

[0037] The present invention aims to design a technology for improving the heating stability of thermal power generating units by utilizing soil heat storage. Without affecting the thermal power generating units' participation in deep peak-shaving scheduling of the power grid, the heat energy in the heating steam extraction during the peak output period of the units is stored in the underground soil. When the units participate in deep peak-shaving and the heating steam extraction capacity decreases, the heat is released to supplement the heat load of the insufficient heating capacity of the units, thereby improving the overall operating stability of the heating system.

[0038] Figure 2This is the process of the heating system of a traditional thermal power plant. The unit uses the exhaust steam from the medium-pressure cylinder and the heating network heater to heat the circulating water. Figure 3 As described above, hot water is used to store heat during the peak period of the unit, and soil heat storage is used as a supplement when the unit is adjusted deeply and the steam supply capacity decreases, so as to make up for the insufficient heat supply.

[0039] The method of the present invention utilizes soil heat storage to store the heat of the heat network circulating water in the soil. When the unit participates in deep peak regulation and the heating steam extraction capacity is insufficient, the heat stored in the soil is released through the heat network circulating water to smooth the impact of the fluctuation of the heating steam extraction volume on the stability of the heating supply, and at the same time, it can also improve the peak operation capacity of the unit during the extreme cold period. In addition, the units participating in the spot electricity trading can arrange energy storage in advance according to the changes in the unit load, and store the heat contained in the unit's heating steam extraction in the soil energy storage device in advance, so as to reduce the situation where the unit load is limited by the heating load during the future operation of the unit.

[0040] like Figure 3 and Figure 4 As shown in the figure, the soil heat accumulator has a casing structure. When storing heat, hot water flows in from the inside of the casing, exchanges heat with the surrounding low-temperature soil, and then enters the heat network return water. During the heat release process, the heat network return water enters the soil heat accumulator, bringing the heat in the soil to the heat network water supply. The outer surface of the heat exchanger is arranged with fins to enhance the heat exchange effect, which has increased the heat storage and heat release rate and improved the heat transfer efficiency of the system. Thermocouple temperature measurement points are evenly arranged around the soil heat accumulator to monitor the operating status of the heat storage system and calculate the heat storage and heat release.

[0041] The heat storage and heat release can be calculated based on the inlet and outlet temperatures of the heat network circulating water in the soil energy storage heat exchanger and the circulating water flow rate. The formula is as follows:

[0042]

[0043] Among them, Q 储1 is the heat storage; C p Specific heat capacity of circulating water in the heating network; ρ is the circulating water density; V is the circulating water flow rate; T2 is the circulating water inlet temperature; T1 is the circulating water outlet temperature; t1 is the start time of heat storage; t2 is the end time of heat storage.

[0044] The heat release is expressed as:

[0045]

[0046] Among them, Q 放1 is the amount of heat released; t3 is the start time of heat release; t4 is the end time of heat release.

[0047] The ratio of heat release to heat storage is the heat storage efficiency, which is expressed as:

[0048]

[0049] Where η is the heat storage efficiency.

[0050] In addition, the heat storage capacity can be calculated based on the soil heat transfer, the formula is as follows:

[0051]

[0052] Where α is the soil heat transfer coefficient; T is the soil temperature; τ is the time; It is the second-order partial derivative of temperature at the spatial coordinates x, y, and z, indicating the spatial variation of temperature distribution in the soil.

[0053] The soil heat storage is expressed as:

[0054] Q 储2 =ρ 土壤 C p，土壤 ∫∫∫ΔTdv

[0055] Among them, Q 储2 Stores heat in the soil; 土壤 is soil density; C p，土壤 is the specific heat capacity of soil; ΔT is the change in soil temperature; v represents the volume of soil.

[0056] It should be noted that the heat storage refers to the heat calculated by storing the heat of the heat network circulating water in the soil through the heat storage heat exchanger. Based on the inlet and outlet temperature changes of the circulating water, the circulating water flow rate and time, the heat stored in the heat storage heat exchanger in a specific period of time is calculated, which is directly related to the flow characteristics of the circulating water in the heat network.

[0057] Soil heat storage refers to the amount of heat that the soil itself can store within a certain volume, which is related to the physical properties and heat distribution of the soil. It is calculated based on the soil's density, specific heat capacity, thermal conductivity, and temperature distribution, reflecting the total heat storage capacity of the soil as a heat storage medium, which is different from the instantaneous heat exchange capacity of the heat storage heat exchanger.

[0058] The present embodiment also provides a system for improving heating capacity by utilizing soil heat storage, including: a collection module, which collects data of thermal power units to determine whether the heating steam extraction capacity meets the load demand; a heat storage module, which stores heat through a soil heat accumulator when the heating steam extraction capacity meets the load demand; a heat release module, which releases heat through a soil heat accumulator when the heating steam extraction capacity is insufficient; and an adjustment module, which calculates heat storage and release parameters based on the thermal power unit data, dynamically adjusts the heat release rate, and smoothes out heating load fluctuations.

[0059] Example 2, below, is an embodiment of the present invention, which provides a method for improving heating capacity by utilizing soil heat storage. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0060] Taking a 600MW unit as an example, its heating steam extraction capacity under different load conditions is shown in the following table.

[0061] Table 1 Permissible operating range of a 600MW unit for single-unit heating extraction during the heating season

[0062] Heating steam extraction capacity (t / h) Load(MW) Load(MW) 200 140 585 400 150 530 600 200 480 800 270 430 1000 330 390

[0063] It can be seen from the table that the larger the steam extraction of the unit, the narrower the unit's allowable operating range. When the demand for heating steam extraction is reduced from 1000t / h to 400t / h, the unit load change range is increased from 60MW to 380MW. It can be seen that after adopting soil energy storage and thermal storage technology, the peak load regulation capacity of the unit has been greatly increased.

[0064] In summary, the method of the present invention has the following advantages: high thermal efficiency: the thermal efficiency of the soil thermal storage reservoir can reach more than 75%, which is one of the lowest cost thermal storage technologies currently;

[0065] Large heat storage capacity: Soil has the characteristics of large thermal inertia, large volume, and relatively slow temperature change. It is a good heat source and heat storage body. It can be used for large-scale energy storage to overcome the influence of random group load fluctuations in heating steam supply;

[0066] Good economic efficiency: The cost of soil thermal storage heating is only about 1 / 3 of that of other energy storage technologies, with low construction and maintenance costs, and good economic efficiency;

[0067] Wide distribution of resources: Soil resources are widely present in the natural environment and are cheap and easy to obtain compared to other heat storage materials;

[0068] Small footprint: The soil thermal storage device is built underground, and only the machine room needs to be built on the ground, saving precious ground space resources.

[0069] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0070] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0071] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0072] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for improving heating capacity by using soil heat storage, characterized in that: include: Collect data from thermal power units to determine whether the heating steam extraction capacity meets the load demand; When the heating steam extraction capacity meets the load demand, the heat is stored in the soil heat storage tank; When the heating steam extraction capacity is insufficient, heat is released through the soil heat storage; The heat storage and release parameters are calculated based on the data of thermal power units, and the heat release rate is adjusted dynamically to smooth out heating load fluctuations.

2. The method for improving heating capacity by utilizing soil heat storage as claimed in claim 1, characterized in that: The thermal power unit data include the inlet and outlet temperatures, flow rate, soil temperature of the heat network circulating water, and the heating steam extraction flow rate and pressure of the thermal power unit.

3. The method for improving heating capacity by utilizing soil heat storage as claimed in claim 2, characterized in that: The soil heat accumulator has a casing structure inside, fins for enhancing the heat exchange effect are arranged on the outer surface, and thermocouple temperature measuring points are evenly arranged around it.

4. The method for improving heating capacity by utilizing soil heat storage as claimed in claim 3, characterized in that: The heat storage by the soil heat accumulator includes that during heat storage, hot water flows into the inside of the casing, exchanges heat with the surrounding low-temperature soil, and then enters the heat network return water.

5. The method for improving heating capacity by utilizing soil heat storage as claimed in claim 4, characterized in that: The releasing of heat through the soil heat accumulator includes that when releasing heat, the return water of the heating network enters the soil heat accumulator, and brings the heat in the soil to the water supply of the heating network.

6. The method for improving heating capacity by utilizing soil heat storage as claimed in claim 5, characterized in that: The heat storage and heat release parameters include heat storage, heat release, heat storage efficiency and soil heat storage. The heat storage and heat release are calculated based on the inlet and outlet temperatures of the heat network circulating water in the soil heat storage and the circulating water flow rate. The heat storage is expressed as: Among them, Q 储1 is the heat storage; C p Specific heat capacity of circulating water in the heat network; ρ is the circulating water density; V is the circulating water flow rate; T2 is the circulating water inlet temperature; T1 is the circulating water outlet temperature; t1 is the start time of heat storage; t2 is the end time of heat storage; The heat release is expressed as: Among them, Q 放1 is the heat release; t3 is the start time of heat release; t4 is the end time of heat release; The ratio of heat release to heat storage is the heat storage efficiency, which is expressed as: Where η is the heat storage efficiency.

7. The method for improving heating capacity by utilizing soil heat storage as claimed in claim 6, characterized in that: The soil heat storage is calculated based on the measured heat transfer of the soil and is expressed as: Q 储2 =ρ 土壤 C p，土壤 ∫∫∫ΔTdv Among them, Q 储2 Stores heat in the soil; 土壤 is soil density; C p，土壤 is the specific heat capacity of soil; ΔT is the change in soil temperature; v represents the volume of soil.

8. A system for improving heating capacity by utilizing soil heat storage according to any one of the methods of claims 1 to 7, characterized in that: include, The acquisition module collects data from thermal power units to determine whether the heating steam extraction capacity meets the load demand; Heat storage module, when the heating steam extraction capacity meets the load demand, heat is stored through the soil heat accumulator; Heat release module, when the heating steam extraction capacity is insufficient, releases heat through the soil heat storage; The adjustment module calculates the heat storage and release parameters based on the data of the thermal power units, dynamically adjusts the heat release rate, and smoothes out heating load fluctuations.

9. A computer device comprising: Memory and processor; The memory stores a computer program, characterized in that when the processor executes the computer program, the steps of the method for improving heating capacity by utilizing soil heat storage as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for improving heating capacity by utilizing soil heat storage as described in any one of claims 1 to 7 are implemented.

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