Gravity energy storage lower bin waste heat power and residual moisture amount calculation method based on vertical shaft

Abstract

The invention discloses a vertical shaft-based gravity energy storage lower bin waste heat power and residual moisture amount calculation method, which comprises the following steps of: assuming that the distribution of surrounding rock temperature along with the distance of a tunnel wall under an initial condition is an arbitrary function f (x), obtaining a one-dimensional heat conduction definite solution problem of the surrounding rock of the tunnel wall, and further calculating the waste heat power; it is assumed that evaporation of water on the surface of the lower bin tunnel wall is divided into two parts, one part is a gap part of a lower bin concrete lining, bed rock crack water seeps, seeped water flow is distributed with a certain width, and the range with the water flow distribution is regarded as the gap part; the other part is a general part except the gap part of the lower bin tunnel wall; and the residual moisture amount is calculated by integrating the two parts. According to the method for calculating the waste heat power and the waste moisture amount of the gravity energy storage lower bin based on the vertical shaft, an effective solution is provided, the blank in the prior art is filled, and therefore the gravity energy storage system can be better constructed, and the requirements of maintainers, electrical equipment and mechanical equipment of the lower bin are better met.

Description

Technical Field

[0001] The invention belongs to the technical field of gravity energy storage, and in particular relates to a method for calculating residual heat power and residual moisture in a lower bin of a gravity energy storage based on a shaft. Background Art

[0002] As the proportion of new energy continues to increase and the electricity trading market gradually improves, various energy storage technologies have ushered in huge development opportunities. The gravity energy storage technology based on the shaft is a large-scale, long-term physical energy storage power generation technology that can achieve peak shaving and valley filling of electric energy. Its technical principles are as follows: Figure 1 As shown. During the off-peak electricity price stage, the power station uses electric energy to drive the motor to lift the heavy objects in the lower warehouse to the upper warehouse through the shaft in sequence, and the electric energy is converted into potential energy stored in the heavy objects in the upper warehouse, realizing the energy storage process; during the peak electricity consumption period, the heavy objects in the upper warehouse on the surface are lowered to the lower warehouse through the shaft in sequence. During the lowering process, the potential energy of the heavy objects is converted into rotational kinetic energy, driving the generator to generate electricity, realizing the energy release process.

[0003] The buried depth of the gravity energy storage lower warehouse can reach hundreds of meters or even thousands of meters. At such a great depth, the temperature of the surrounding rock of the lower warehouse is relatively high. According to the stratum temperature increase gradient, the rock wall temperature of the lower warehouse at a depth of 1000m can reach 30~50℃. Under the condition of high surrounding rock temperature, the air temperature in the lower warehouse is relatively high. Under the condition of long-term lack of ventilation, the air temperature in the lower warehouse will be consistent with the surrounding rock temperature.

[0004] Due to the large buried depth of the lower warehouse, the bedrock fissure water pressure on the outer side of the concrete lining of the lower warehouse wall is relatively large, which can reach 5~10MPa. At the joints of the lining casting, bedrock fissure water may seep out; on the surface of the lining, bedrock fissure water can seep out directly through infiltration. These seeped groundwater evaporates and enters the air in the lower warehouse, increasing the humidity of the air in the lower warehouse. Under the condition of long-term non-ventilation, the air humidity in the lower warehouse will reach 100%.

[0005] When ventilation measures are taken in the lower warehouse to keep the air temperature and humidity in the lower warehouse constant, there is convective heat exchange between the cave wall and the air in the cave, generating the so-called residual heat; water seeping from the cave wall evaporates into the air, generating the so-called residual moisture. The calculation of residual heat power and residual moisture determines the selection and design of ventilation measures.

[0006] Unlike the mining industry, the lower warehouse of gravity energy storage has no dust and gas problems. The temperature and humidity environment requirements of the lower warehouse mainly depend on the maintenance personnel, electrical equipment and mechanical equipment requirements of the lower warehouse. The calculation of the residual heat power and residual humidity of the lower warehouse space of gravity energy storage under the required environmental conditions is an important content and the basic basis for the ventilation plan of the lower warehouse. Therefore, the present invention proposes a method for calculating the residual heat power and residual humidity of the lower warehouse under the normal operating conditions of the gravity energy storage power station. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for calculating the waste heat power and residual moisture in the lower warehouse of a gravity energy storage system based on a shaft, so as to solve the problem that there is a lack of basis for the selection and design of ventilation measures for the lower warehouse at present, realize the calculation of the waste heat power and residual moisture in the lower warehouse under the normal operating conditions of a gravity energy storage power station, and provide technical support for the construction of a gravity energy storage system.

[0008] According to the technical scheme of the present invention, the present invention provides a method for calculating the residual heat power and residual moisture of the lower warehouse of gravity energy storage based on a shaft, and the conceptual model used for the calculation includes the following assumptions: the air in the lower warehouse is constant temperature and humidity; the surrounding rock temperature is uniformly distributed under initial conditions; the surrounding rock thermophysical parameters are consistent with the thermophysical parameters of the lining of the lower warehouse wall; the influence range of the lower warehouse air temperature change on the surrounding rock temperature is limited, and the heat conduction of the surrounding rock of the wall can be simplified to one-dimensional heat conduction, and the influence range is constant with the temperature of the outer rock; the convection heat transfer conditions of the lower warehouse wall in all directions are consistent; the evaporation and heat absorption of water on the surface of the lower warehouse wall are ignored; the evaporation of water on the surface of the lower warehouse wall is divided into two types of parts, and the amount of water entering the air is composed of these two parts, one type of part is the gap part of the concrete lining of the lower warehouse, there is water seeping out of the bedrock fissures, the seeping water flow distribution has a certain width, and the range with water flow distribution is regarded as the gap part; the other part is the general part of the lower warehouse wall except the gap part; Based on the above conceptual model, the mathematical model used for calculation includes the following: For the calculation of waste heat power, it is assumed that the distribution of surrounding rock temperature with distance from the cave wall under initial conditions is an arbitrary function f ( x ), then the one-dimensional heat conduction problem of the surrounding rock of the cave wall is solved as follows: , In the formula, T c is the surrounding rock temperature; x is the distance from the inner wall of the lower bin; t For time; a c is the thermal diffusion coefficient of surrounding rock; L cr is the distance between the outer boundary of the surrounding rock heat conduction and the inner wall of the lower bin; T cm is the temperature of the concrete lining on the inner surface of the lower bin; T R0 is the initial temperature of surrounding rock; The waste heat power is calculated according to the following formula 5: , In the formula, w cd ( t ) is the convection heat transfer power between the inner surface of the lower chamber wall lining and the air in the lower chamber, that is, the waste heat power; T a0The temperature required for the lower warehouse; A c is the inner surface area of ​​the lower bin; h c is the convective heat transfer coefficient, which is calculated by the following formula 6: , v is the average air velocity in the lower chamber; For residual moisture calculation, the residual moisture in the gap is calculated using the following formula: , In the formula, E e The evaporation amount of bedrock fissure water in the lining gap; r is the relative humidity of the air in the lower warehouse; v is the average air velocity in the lower chamber; The residual moisture content of general parts is calculated using the following formula: , In the formula, E d It is the water seepage rate of bedrock fissures in general parts of concrete lining; K c is the permeability coefficient of the concrete lining; η is the external water pressure reduction factor; H w is the height of bedrock fissure water head; B c is the lining thickness; Combining the above two parts, the residual moisture is calculated according to the following formula 9: , Where, E is the amount of water entering the lower chamber, i.e., residual moisture; B fx L is the width of water seepage in the lining gap; fx is the cumulative length of lining gap; ρ w is the specific gravity of water.

[0009] Furthermore, a method of discretizing time is adopted in the calculation and solution. It is assumed that in each time step, the boundary conditions of heat conduction inside the surrounding rock and the convective heat transfer between the surrounding rock and the air in the lower warehouse are constant conditions, and the boundary conditions are solved as constant boundary conditions. The calculation process of each time step includes: calculating the convective heat transfer power of the lower warehouse wall, obtaining the heat conduction power of the cave wall based on the temperature distribution, and then obtaining the temperature of the concrete lining on the inner surface of the lower warehouse according to the equality of the convective heat transfer power and the heat conduction power. T cm ,by T cm As the boundary condition, one-dimensional heat conduction calculation of the cave wall is carried out to obtain the new temperature distribution of the cave wall (surrounding rock); after obtaining the temperature distribution of the surrounding rock, the residual heat power of the surrounding rock to the air, the evaporation amount and residual moisture of the cave wall are calculated.

[0010] Furthermore, for the solution of the one-dimensional heat conduction equation, the problem of determining the heat conduction of the surrounding rock is decomposed into the following two problems: Steady-state nonhomogeneous problem: , The solution to this problem is: , In the formula, T cw The surrounding rock temperature of the lower chamber for the steady-state nonhomogeneous problem; Unsteady Homogeneous Problem: , The solution to this problem is: ; In the formula, T cf The surrounding rock temperature of the lower chamber for the non-steady-state homogeneous problem; The solutions of the original solution formula 1 to formula 4 are: ; Substituting Formula 13 and Formula 18 into Formula 19 and rearranging them, we obtain: , In the formula, β m is the eigenvalue, , m is a natural number, m =1, 2, 3,…,∞.

[0011] Compared with the prior art, the beneficial technical effects of the present invention are as follows: The calculation of the residual heat power and residual moisture of the lower warehouse space of gravity energy storage under the required environmental conditions is an important content and the basic basis for the ventilation plan of the lower warehouse. The method for calculating the residual heat power and residual moisture of the lower warehouse of gravity energy storage based on the shaft of the present invention proposes an effective solution for this, filling the gap in the prior art, thereby contributing to better construction of the gravity energy storage system and better meeting the requirements of maintenance personnel, electrical equipment and mechanical equipment in the lower warehouse. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a basic structural diagram of a gravity energy storage system based on a vertical shaft.

[0013] Figure 2 It is a schematic diagram of a conceptual model for calculating residual heat power and residual moisture in a long-term vacant lower warehouse condition according to an embodiment of the present invention.

[0014] Figure 3aThe figure is a schematic diagram of the structure of the evaporation area of ​​the lower bin side wall according to an embodiment of the present invention.

[0015] Figure 3b It is a schematic diagram of the cross-sectional structure of the lower bin according to an embodiment of the present invention.

[0016] Figure 4 It is a calculation flow chart of each time step of an embodiment of the present invention.

[0017] Figure 5 This is a curve diagram of the change of the lower bin waste heat power over time according to an embodiment of the present invention.

[0018] Figure 6 This is a curve diagram of the change of the residual moisture content in the lower bin over time according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The present invention provides a method for calculating the residual heat power and residual moisture of the lower warehouse of a gravity energy storage system based on a shaft, which solves the problem that there is a lack of basis for the selection and design of ventilation measures for the lower warehouse at present, realizes the calculation of the residual heat power and residual moisture of the lower warehouse under the normal operating conditions of the gravity energy storage power station, and provides technical support for the construction of the gravity energy storage system.

[0020] The basic structure of the gravity energy storage system based on the shaft of the present invention is as follows: Figure 1 As shown, it includes an upper warehouse 1 located above the ground, a gravity turbine system 2 and a plant 3, and a lower warehouse 6 located below the ground. The upper warehouse 1 and the lower warehouse 6 are connected by a shaft 4. The gravity turbine system 2 realizes the lifting and movement of a heavy object 7 (usually a block) in the shaft 4 by, for example, a wire rope transmission, and the heavy object 7 can be moved and stored by the transmission system in the upper and lower warehouses; the lower warehouse 6 is surrounded by surrounding rock 5 (the part close to the internal space of the lower warehouse 6 is called the cave wall, and the surface of the cave wall has a concrete lining structure layer). This basic structure is an existing technology, and this solution can also be applied to other similar gravity energy storage systems to analyze and solve the problems related to temperature and humidity control caused by the deep burial depth of the lower warehouse.

[0021] The computational models used in this scheme include conceptual models and mathematical models.

[0022] The conceptual model includes the following contents.

[0023] In gravity energy storage projects, the lower warehouse generally adopts a crisscross tunnel scheme. The rail transit tunnel is connected to the vertical shaft, and the vertical shaft realizes the vertical path of gravity energy storage. The volume of the lower warehouse is generally thousands to tens of thousands of cubic meters. The heavy objects are concrete blocks or cast iron blocks. The single heavy object is several tons to tens of tons, and the total number can reach hundreds of blocks.

[0024] Under normal operating conditions of the energy storage power station, heavy objects frequently enter and exit the lower warehouse, and a heat exchange process occurs on the contact surface between the heavy objects and the air, and a heat conduction process occurs inside the heavy objects. The temperature of the heavy objects stored in the upper warehouse is generally lower than the temperature of the surrounding rock in the lower warehouse. Therefore, the frequent entry and exit of heavy objects is conducive to lowering the temperature of the lower warehouse and reducing the evaporation of water on the wall of the lower warehouse.

[0025] When the energy storage power station is not in operation, that is, when the lower warehouse is vacant for a long time, necessary heat removal and dehumidification measures need to be taken in the warehouse to ensure that the air temperature and humidity reach the required temperature and humidity. Under this condition, the temperature of the surrounding rock of the cave wall is higher than the air temperature of the lower warehouse, and a convection heat exchange process occurs at the contact surface between the inner surface of the cave wall lining and the air; a heat conduction process occurs in the surrounding rock of the cave wall; and water evaporation occurs on the cave wall.

[0026] Therefore, the long-term vacancy condition of the lower warehouse is the control condition of the residual heat power and residual moisture in the lower warehouse. The residual heat power and residual moisture calculated according to the vacancy condition can be used as the basis for engineering ventilation design.

[0027] According to the above analysis and the actual situation of the warehouse, the following is proposed: Figure 2 The conceptual model for calculating the residual heat power and residual moisture under the condition of long-term vacancy of the lower warehouse is shown in the figure. In the figure, E refers to the evaporation on the surface of the concrete lining.

[0028] To simplify the calculation, the following assumptions are made: 1) The air in the lower warehouse is kept at a constant temperature and humidity; 2) The surrounding rock temperature is uniformly distributed under initial conditions, and its value is equal to the initial temperature of the surrounding rock; 3) The thermophysical parameters of the surrounding rock are consistent with those of the lower warehouse wall lining; 4) The influence range of the change of air temperature in the lower chamber on the surrounding rock temperature is limited. The heat conduction of the surrounding rock of the cave wall can be simplified to one-dimensional heat conduction, and the influence range is constant with the temperature of the surrounding rock; 5) The convection heat transfer conditions of the lower chamber wall are consistent in all directions; 6) The heat absorption caused by evaporation of water on the surface of the lower warehouse wall is small and can be ignored.

[0029] Depending on whether there is sufficient water supply, the evaporation of water on the surface of the lower warehouse wall can be divided into two types of parts. One type of part is the gap part of the lower warehouse concrete lining. This part is the concrete pouring joint, and its integrity is generally poor. There is often water seepage from the bedrock fissures, and the seepage amount is greater than the evaporation amount. The water that cannot evaporate flows into the drainage ditch located on the bottom plate of the warehouse for discharge. Generally speaking, the joints of the concrete lining are very narrow, but after the bedrock fissure water seeps out, the water flow distribution generally has a certain width. Within this width range, the evaporated water supply is sufficient. Therefore, the range with water flow distribution is regarded as the gap part. The other part is the general part of the lower warehouse wall excluding the gap part. This part is controlled by the water-blocking effect of the lining, and the seepage amount of bedrock fissure water is generally less than the evaporation amount. The actual amount of water entering the air should be composed of these two parts. See the schematic diagram of the evaporation part division and drainage ditch after the lower warehouse side wall is unfolded. Figure 3a , Figure 3b Specifically, the cross section of the lower bin is a rectangle with a semicircular arch 9, the boundary line between the rectangle and the arch 9 on the side wall 8 is an arch line 10, the bottom of the side wall 8 is a bottom plate 11, and both sides of the side wall 8 have recessed drainage ditches 14; the side wall 8 of the lower bin has the aforementioned gap portion 12 and a general portion 13 other than the gap portion 12; the side wall 8 and the inner side of the arch are lined, and the outer side of the lining is surrounding rock.

[0030] Based on the above conceptual model, the mathematical model used for calculation includes the following contents.

[0031] For the calculation of waste heat power, in order to achieve the coupling of heat conduction of the cave wall and the thermodynamic process of the air in the lower chamber, it is assumed that the distribution of the surrounding rock temperature with the distance from the cave wall under the initial conditions is an arbitrary function f ( x ), then the one-dimensional heat conduction problem of the surrounding rock of the cave wall is solved as follows: , In the formula, T c is the surrounding rock temperature, which is a function of position and time, in K; x is the distance from the inner wall of the lower bin, in m; t is the time, in seconds; a c is the thermal diffusion coefficient of the surrounding rock, in m 2 ⁄s; L cr is the distance between the outer boundary of the surrounding rock heat conduction and the inner wall of the lower bin, in meters; T cm is the temperature of the concrete lining on the inner surface of the lower bin, which is a function that changes with time and is in K; TR0 is the initial temperature of the surrounding rock, in K.

[0032] The convection heat transfer power (i.e., waste heat power) between the inner surface of the lower chamber wall lining and the air in the lower chamber is calculated according to the following formula 5: , In the formula, w cd ( t ) is the convection heat transfer power between the inner surface of the lower chamber wall lining and the air in the lower chamber, that is, the waste heat power, in W; T a0 The temperature required for the lower warehouse is a constant value in K. A c is the inner surface area of ​​the lower bin, in m 2 ; h c is the convective heat transfer coefficient, in W⁄(m 2 K), is calculated by the following formula 6: , v It is the average air velocity in the lower chamber, in m / s.

[0033] For the calculation of residual moisture, the water in the bedrock fissures at the lining casting joints seeps out quickly, the water replenishment is sufficient, the evaporation rate is lower than the seepage rate, and the amount of water evaporated into the air at this location is limited by the evaporation amount. Considering that the silo wall temperature is higher than the air temperature in the lower silo, its evaporation process is similar to the evaporation amount during the concrete curing process, so the calculation formula in the "Technical Specifications for Curing of Cast-in-Place Concrete" (JC / T60018-2023) is used, that is, the residual moisture at the gap is calculated using the following formula: , In the formula, E e The evaporation amount of bedrock fissure water in the lining gap, in mm / d; r is the relative humidity of the air in the lower warehouse, which is a constant value in %; v It is the average air velocity in the lower bin, which is determined by the ratio of the ventilation volume of the lower bin to the cross-sectional area of ​​the lower bin, and the unit is km / h.

[0034] In general, the water seepage rate of bedrock fissures is lower than the evaporation rate, and the amount of water entering the air in this part is controlled by the seepage rate. The water seepage rate of bedrock fissures is determined according to Darcy's law, that is, the residual moisture in general parts is determined by the following formula: , In the formula,E d is the water seepage rate of bedrock fissures in general parts of concrete lining, in mm / d; K c is the permeability coefficient of the concrete lining, in m / s; η is the external water pressure reduction factor, dimensionless; H w is the height of bedrock fissure water head, in m, measured from the bottom plate of the lower bin; B c is the lining thickness, in m.

[0035] Combining the above two parts, the amount of water entering the air (i.e., residual moisture) is calculated according to the following formula 9: , In the formula, E is the amount of water entering the lower bin air, that is, the residual moisture, the unit is t / h; B fx The width of water seepage in the lining joints, in m; L fx is the cumulative length of lining gaps, in m; ρ w is the bulk density of water, in t / m 3 .

[0036] As for the solution method, in the calculation model, the convection heat exchange between the cave wall and the air is considered. The air temperature in the cave is constant, but the cave wall temperature gradually increases with time. Therefore, due to the boundary conditions of the solution problem defined by formulas 1 to 4, the temperature of the concrete lining on the surface of the warehouse is T cm (i.e., the surface temperature of the cave wall) is a function that changes with time, and it is difficult to directly solve the above problem.

[0037] To this end, this scheme adopts the time discretization method, assuming that in each time step, the heat conduction inside the surrounding rock and the convection heat exchange boundary conditions with the air in the lower warehouse are constant value conditions, which can be used as constant value boundary conditions to solve this model. The calculation process of each time step is as follows Figure 4 As shown, it includes: calculating the convection heat transfer power of the lower warehouse wall, obtaining the heat conduction power of the cave wall based on the temperature distribution, and then obtaining the temperature of the concrete lining on the inner surface of the lower warehouse according to the equality of the convection heat transfer power and the heat conduction power. T cm ,by T cmAs the boundary condition, one-dimensional heat conduction calculation of the cave wall is carried out to obtain the new temperature distribution of the cave wall (surrounding rock). After obtaining the temperature distribution of the surrounding rock, the residual heat power of the surrounding rock to the air, the evaporation amount and residual moisture of the cave wall can be calculated.

[0038] Furthermore, for the solution of the one-dimensional heat conduction equation, the problem of solving the surrounding rock heat conduction problem can be decomposed into the following two problems: (1) Steady-state nonhomogeneous problem: , The solution to this problem is: , In the formula, T cw The surrounding rock temperature of the lower chamber for the steady-state nonhomogeneous problem; (2) Non-steady-state homogeneous problem: , The solution to this problem is: ; In the formula, T cf The surrounding rock temperature of the lower chamber for the non-steady-state homogeneous problem; The solutions of the original solution formula 1 to formula 4 are: ; Substituting Formula 13 and Formula 18 into Formula 19 and rearranging them, we obtain: , In the formula, β m is the eigenvalue, , m is a natural number, m =1, 2, 3,…,∞.

[0039] The solution to the fixed-point problem involves the summation of infinite series. In actual calculation, the cutoff value can be determined through trial calculation, and m can be taken as 30.

[0040] In order to facilitate a more intuitive understanding of this calculation method and its function, a specific example is given below.

[0041] The parameters required for calculating the residual heat power and residual moisture of the lower warehouse of the gravity energy storage based on the shaft are divided into three parts: lower warehouse, air and groundwater parameters, see Table 1 to Table 3. The total calculation time is 30 days and the time step is 30 seconds.

[0042] Table 1 Lower warehouse parameters

[0043] Table 2 Air parameters

[0044] Table 3 Groundwater parameters

[0045] According to the above mathematical model and solution method, the temperature distribution of the surrounding rock at each time node can be obtained, and then the curves of residual heat power and residual moisture changing with time can be obtained ( Figure 5~Figure 6 ). In the initial stage, the temperature of the lower chamber wall is quite different from the air temperature in the lower chamber, the convective heat transfer and evaporation are obvious, the residual heat power is large, and the residual humidity is large. As time goes by, the heat conduction of the chamber wall proceeds, the chamber wall temperature decreases, and the convective heat transfer and evaporation weaken. From the calculation results, it can be seen that in order to keep the air temperature and humidity in the lower chamber constant, it is necessary to continuously adjust the heat removal and dehumidification power. However, from the perspective of engineering design, it is only necessary for the temperature and humidity of the lower chamber to reach the required values ​​within a given time, so it can be based on Figure 5 and Figure 6 The average residual heat power and residual humidity of the lower warehouse can be obtained by taking the average value of the curve within a given time period.

[0046] When the given time is 3d and 30d, the corresponding average waste heat power and residual moisture are shown in Table 4. As can be seen from Table 4, the longer the given time is, the smaller the waste heat power and residual moisture are, which is consistent with theoretical analysis and engineering judgment.

[0047] Table 4: Residual heat power and residual humidity of lower warehouse

Claims

1. A method for calculating the residual heat power and residual humidity of the lower warehouse of a gravity energy storage based on a shaft, characterized in that: The conceptual model used in the calculation includes the following assumptions: the air in the lower chamber is of constant temperature and humidity; the surrounding rock temperature is uniformly distributed under initial conditions; the surrounding rock thermophysical parameters are consistent with the thermophysical parameters of the lower chamber wall lining; the influence of the lower chamber air temperature change on the surrounding rock temperature is limited, and the heat conduction of the surrounding rock of the chamber wall can be simplified to one-dimensional heat conduction, and the influence range is constant with the surrounding rock temperature; The convection heat transfer conditions of the lower chamber wall are the same in all directions; the heat absorption due to evaporation of water on the surface of the lower chamber wall is ignored; The evaporation of water on the surface of the lower warehouse wall is divided into two parts. The amount of water entering the air is composed of these two parts. One part is the gap part of the lower warehouse concrete lining, where bedrock fissure water seeps out. The seepage water flow distribution has a certain width, and the range with water flow distribution is regarded as the gap part; the other part is the general part of the lower warehouse wall except the gap part; Based on the above conceptual model, the mathematical model used for calculation includes the following: For the calculation of waste heat power, it is assumed that the distribution of surrounding rock temperature with distance from the cave wall under initial conditions is an arbitrary function f ( x ), then the one-dimensional heat conduction problem of the surrounding rock of the cave wall is solved as follows: ， In the formula, T c is the surrounding rock temperature; x is the distance from the inner wall of the lower bin; t For time; a c is the thermal diffusion coefficient of surrounding rock; L cr is the distance between the outer boundary of the surrounding rock heat conduction and the inner wall of the lower bin; T cm is the temperature of the concrete lining on the inner surface of the lower bin; T R0 is the initial temperature of surrounding rock; The waste heat power is calculated according to the following formula 5: ， In the formula, w cd ( t ) is the convection heat transfer power between the inner surface of the lower chamber wall lining and the air in the lower chamber, that is, the waste heat power; T a0 The temperature required for the lower warehouse; A c is the inner surface area of ​​the lower bin; h c is the convective heat transfer coefficient, which is calculated by the following formula 6: , v is the average air velocity in the lower chamber; For residual moisture calculation, the residual moisture in the gap is calculated using the following formula: ， In the formula, E e The evaporation amount of bedrock fissure water in the lining gap; r is the relative humidity of the air in the lower warehouse; v is the average air velocity in the lower chamber; The residual moisture content of general parts is calculated using the following formula: ， In the formula, E d It is the water seepage rate of bedrock fissures in general parts of concrete lining; K c is the permeability coefficient of the concrete lining; η is the external water pressure reduction factor; H w is the height of bedrock fissure water head; B c is the lining thickness; Combining the above two parts, the residual moisture is calculated according to the following formula 9: ， Where, E is the amount of water entering the lower chamber, i.e., residual moisture; B fx L is the width of water seepage in the lining gap; fx is the cumulative length of lining gap; ρ w is the specific gravity of water.

2. The method for calculating the residual heat power and residual humidity of the lower warehouse of the gravity energy storage based on the shaft according to claim 1 is characterized in that: The method of discretizing time is adopted in the calculation and solution. It is assumed that in each time step, the boundary conditions of heat conduction inside the surrounding rock and convection heat transfer with the air in the lower warehouse are constant value conditions, and the solution is taken as the constant value boundary conditions. The calculation process for each time step includes: calculating the convection heat transfer power of the lower warehouse wall, obtaining the heat conduction power of the cave wall based on the temperature distribution, and then obtaining the temperature of the concrete lining on the inner surface of the lower warehouse based on the equality of the convection heat transfer power and the heat conduction power. T cm ,by T cm As the boundary condition, one-dimensional heat conduction calculation of the cave wall is carried out to obtain the new temperature distribution of the cave wall (surrounding rock); after obtaining the temperature distribution of the surrounding rock, the residual heat power of the surrounding rock to the air, the evaporation amount and residual moisture of the cave wall are calculated.

3. The method for calculating the residual heat power and residual humidity of the lower warehouse of the gravity energy storage based on the shaft according to claim 1 is characterized in that: For the solution of the one-dimensional heat conduction equation, the problem of determining the heat conduction of the surrounding rock is decomposed into the following two problems: Steady-state nonhomogeneous problem: ， The solution to this problem is: ， In the formula, T cw The surrounding rock temperature of the lower chamber for the steady-state nonhomogeneous problem; Unsteady Homogeneous Problem: ， The solution to this problem is: ； In the formula, T cf The surrounding rock temperature of the lower chamber for the non-steady-state homogeneous problem; The solutions of the original solution formula 1 to formula 4 are: ； Substituting Formula 13 and Formula 18 into Formula 19 and rearranging them, we obtain: ， In the formula, β m is the eigenvalue, , m is a natural number, m =1, 2, 3,…,∞.

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