Compressed air energy storage electric-electric efficiency calculation method and device based on equilibrium state

Abstract

The present invention relates to a method for calculating the electric-to-electric efficiency of compressed air energy storage based on a balanced state, comprising the following steps: obtaining the operating output of a turbine unit; obtaining the air flow rate of a compression unit; obtaining the power consumption of the compression unit; obtaining the air flow rate of the turbine unit; determining whether the compressed air energy storage system is in a balanced operating condition; if the compressed air energy storage system is not in a balanced operating condition, adjusting the compressed air energy storage system to a balanced operating condition; calculating the total air consumption during the operating time of the turbine unit; calculating the operating time of the compression unit based on the total air consumption of the turbine unit and the air flow rate of the compression unit; calculating the system output energy based on the operating time of the turbine unit and the operating output of the turbine unit; calculating the system input energy based on the operating time of the compression unit and the power consumption of the compression unit; and calculating the electric-to-electric efficiency of the system based on the system input energy and the system output energy.

Description

Technical Field

[0001] The present invention relates to a method and device for calculating the electric-electric efficiency of compressed air energy storage based on an equilibrium state, and belongs to the field of compressed air energy storage. Background Art

[0002] Compressed air energy storage, as a form of energy storage, is clean, efficient, and scalable, and is one of the most promising energy storage technologies. The thermal system of the compressed air energy storage system includes system components such as a compression unit, a heat exchange unit, a heat storage unit, a turbine unit, and an air storage chamber. When the grid load is low, the compressed air energy storage system absorbs excess electricity from the grid, drives the compression unit to work, and compresses the air into high-pressure air and stores it in the air storage chamber. Heat is generated during the compression process, which is exchanged out through the heat exchange unit and stored in the heat storage unit. When the grid load is peak, the compressed air energy storage system releases high-pressure air from the air storage chamber, enters the turbine unit to expand and work, and generates electricity to be sent to the grid. During the work process, the heat stored in the heat storage unit is absorbed by the heat exchange unit.

[0003] Electric-electric efficiency is one of the key parameters for evaluating compressed air energy storage systems. It is generally calculated by measuring the system's electrical energy input and output and taking into account the energy of other inputs to the system. This method is simple and easy to use, but on the one hand it can only be applied to systems that are already in operation; on the other hand it is difficult to expand its application, such as analyzing the impact of key system parameters on efficiency and optimizing system design parameters. For example, the efficiency of a traditional supplementary combustion compressed air energy storage system is calculated as follows: η = E out / (E in +Qη eff );where E in 、E out , Q are the input and output electric energy of the energy storage system and the heat contained in the input natural gas during the cycle; η eff is the conversion efficiency of natural gas equivalent electricity.

[0004] Patent publication number US20180080346A1, "A Method for Efficiency Evaluation of an RCAES System," discloses: calculating the electrical energy charged by the power system during compression; calculating the electrical energy discharged to the power system during expansion; and calculating the power ratio. The energy released during expansion is related to the energy released during compression, and this ratio is used as the efficiency of the entire RCAES system. The operating gas is an ideal gas, the air mass flow rate during compression and expansion is known and constant during operation, and an isothermal model is used for the CASV, where its temperature is the same as the surrounding environment, and the compressed air becomes constant after temperature and pressure throttling. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, the present invention designs a method and device for calculating the electric-to-electric efficiency of compressed air energy storage based on the equilibrium state. On the basis of the system heat and gas balance calculation, the compression unit operating time is calculated according to the total gas consumption of the turbine unit, and the system output power and system input power are obtained. The set design parameters conform to the system operation rules and can enable the system operation to achieve the optimal design operating conditions. The calculated electric-to-electric efficiency can more accurately reflect the actual efficiency of the system.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] Technical Solution 1

[0008] A method for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state includes the following steps:

[0009] Get the turbine unit operating output W t ;

[0010] Get the compression unit air flow q c ;

[0011] Get the power consumption W of the compression unit c ;

[0012] Get the turbine unit air flow q t ;

[0013] Determine whether the compressed air energy storage system is in a balanced operating condition based on the deviation between the heat storage medium flow rate on the compression side and the heat storage medium flow rate on the turbine side, as well as the deviation between the air flow rate of the compression unit and the air flow rate of the turbine unit; if the compressed air energy storage system is not in a balanced operating condition, adjust the compressed air energy storage system to a balanced operating condition;

[0014] Calculate the turbine unit operating time t in one cycle t The corresponding total gas consumption q t_total According to the total gas consumption of the turbine unit q t_total and compression unit air flow q c , calculate the compression unit running time t in a cycle c ;

[0015] According to the turbine unit operating time t in one cycle t And turbine unit operating output W t , calculate the system output energy; according to the compression unit running time t in a cycle c And the compression unit power consumption W c , calculate the system input energy; based on the system input energy and system output energy, calculate the system electrical-electrical efficiency.

[0016] Furthermore, the compressed air energy storage system is adjusted to a balanced operating condition, specifically:

[0017] Obtaining operating parameters of the compressed air energy storage system, wherein the operating parameters include a heat exchange end difference of a heat exchanger;

[0018] Based on the operating parameters, the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate are calculated; based on the deviation between the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate, and the deviation between the compression unit air flow rate and the turbine unit air flow rate, a balance index is calculated; if the balance index is not within a preset range, it is considered that the compressed air energy storage system is not in a balanced operating condition, and the operating parameters are reset until the compressed air energy storage system reaches a balanced operating condition.

[0019] Furthermore, it is characterized in that the calculation balance index is expressed as follows:

[0020]

[0021] Where n c is the number of compression cylinders; n t is the number of turbine cylinders; q c_w_i is the heat storage medium flow rate in the i-th compression side heat exchanger; q t_w_i is the heat storage medium flow rate in the i-th turbine side heat exchanger; q c is the air flow rate of the compression unit; q t is the air flow of the turbine unit.

[0022] Furthermore, the calculation of the compression side heat storage medium flow rate and the turbine side heat storage medium flow rate is specifically as follows:

[0023] The heat storage medium temperature is calculated based on the heat exchange end difference; the heat storage medium enthalpy value is obtained based on the heat storage medium temperature; the heat storage medium flow rate in the compression side heat exchanger is calculated based on the heat storage medium enthalpy value and the compression unit air flow rate; the heat storage medium flow rate in the turbine side heat exchanger is calculated based on the heat storage medium enthalpy value and the turbine unit air flow rate.

[0024] Furthermore, it also includes:

[0025] Calculate the downtime t of a compressed air energy storage system in one cycle s ;

[0026] Calculate the downtime t of a compressed air energy storage system in one cycle s The corresponding auxiliary equipment consumes energy;

[0027] Calculate the compression unit operating time t in one cycle of the compressed air energy storage system c The corresponding auxiliary equipment consumes energy;

[0028] Calculate the turbine unit operating time t in one cycle of the compressed air energy storage system t The corresponding auxiliary equipment consumes energy;

[0029] Correct the system output energy and system input energy according to the energy consumed by the auxiliary equipment;

[0030] The system electrical-electrical efficiency is calculated based on the corrected system output energy and system input energy.

[0031] Furthermore, the calculation system electric-electric efficiency is expressed as follows:

[0032]

[0033] Where, ε c , ε t , ε s Respectively represent the power consumption of auxiliary equipment during the operation of the compression unit, the operation of the turbine unit, and the system shutdown process of the compressed air energy storage system; W t Indicates the operating output of the turbine unit; t t Indicates the operating time of the turbine unit in one cycle; W c Indicates the power consumption of the compression unit; t c Indicates the running time of the compression unit in one cycle; t s Indicates the downtime of a compressed air energy storage system in one cycle.

[0034] Technical Solution 2

[0035] A device for calculating electric-electric efficiency of compressed air energy storage based on equilibrium state includes a memory and a processor, wherein the memory stores instructions, and the instructions are suitable for being loaded by the processor and executing the following steps:

[0036] Get the turbine unit operating output W t ;

[0037] Get the compression unit air flow q c ;

[0038] Get the power consumption W of the compression unit c ;

[0039] Get the turbine unit air flow q t ;

[0040] Determine whether the compressed air energy storage system is in a balanced operating condition based on the deviation between the heat storage medium flow rate on the compression side and the heat storage medium flow rate on the turbine side, as well as the deviation between the air flow rate of the compression unit and the air flow rate of the turbine unit; if the compressed air energy storage system is not in a balanced operating condition, adjust the compressed air energy storage system to a balanced operating condition;

[0041] Calculate the turbine unit operating time t in one cycle t Total gas consumption q t_total According to the total gas consumption of the turbine unit q t_total and compression unit air flow q c , calculate the compression unit running time t in a cycle c ;

[0042] According to the turbine unit operating time t in one cycle t And turbine unit operating output W t , calculate the system output energy; according to the compression unit running time t in a cycle c And the compression unit power consumption W c , calculate the system input energy; based on the system input energy and system output energy, calculate the system electrical-electrical efficiency.

[0043] Furthermore, the compressed air energy storage system is adjusted to a balanced operating condition, specifically:

[0044] Obtaining operating parameters of the compressed air energy storage system, wherein the operating parameters include a heat exchange end difference of a heat exchanger;

[0045] Based on the operating parameters, the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate are calculated; based on the deviation between the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate, and the deviation between the compression unit air flow rate and the turbine unit air flow rate, a balance index is calculated; if the balance index is not within a preset range, it is considered that the compressed air energy storage system is not in a balanced operating condition, and the operating parameters are reset until the compressed air energy storage system reaches a balanced operating condition.

[0046] Furthermore, it is characterized in that the calculation balance index is expressed as follows:

[0047]

[0048] Where n c is the number of compression cylinders; n t is the number of turbine cylinders; q c_w_i is the heat storage medium flow rate in the i-th compression side heat exchanger; q t_w_i is the heat storage medium flow rate in the i-th turbine side heat exchanger; q c is the air flow rate of the compression unit; q t is the air flow of the turbine unit.

[0049] Furthermore, the calculation of the compression side heat storage medium flow rate and the turbine side heat storage medium flow rate is specifically as follows:

[0050] The heat storage medium temperature is calculated based on the heat exchange end difference; the heat storage medium enthalpy value is obtained based on the heat storage medium temperature; the heat storage medium flow rate in the compression side heat exchanger is calculated based on the heat storage medium enthalpy value and the compression unit air flow rate; the heat storage medium flow rate in the turbine side heat exchanger is calculated based on the heat storage medium enthalpy value and the turbine unit air flow rate.

[0051] Furthermore, it also includes:

[0052] Calculate the downtime t of a compressed air energy storage system in one cycle s ;

[0053] Calculate the downtime t of a compressed air energy storage system in one cycle s The corresponding auxiliary equipment consumes energy;

[0054] Calculate the compression unit operating time t in one cycle of the compressed air energy storage system c The corresponding auxiliary equipment consumes energy;

[0055] Calculate the turbine unit operating time t in one cycle of the compressed air energy storage system t The corresponding auxiliary equipment consumes energy;

[0056] Correct the system output energy and system input energy according to the energy consumed by the auxiliary equipment;

[0057] The system electrical-electrical efficiency is calculated based on the corrected system output energy and system input energy.

[0058] Furthermore, the calculation system electric-electric efficiency is expressed as follows:

[0059]

[0060] Where, ε c , ε t , ε s Respectively represent the power consumption of auxiliary equipment during the operation of the compression unit, the operation of the turbine unit, and the system shutdown process of the compressed air energy storage system; W t Indicates the operating output of the turbine unit; t t Indicates the operating time of the turbine unit in one cycle; W c Indicates the power consumption of the compression unit; t c Indicates the running time of the compression unit in one cycle; t s Indicates the downtime of the compressed air energy storage system in one cycle.

[0061] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0062] 1. Based on the calculation of the system heat and gas balance, the present invention calculates the compression unit operating time according to the total gas consumption of the turbine unit to obtain the system output power and system input power. The set design parameters (such as temperature, pressure, flow, etc.) conform to the system operating rules and can enable the system to operate at the optimal design conditions. The calculated electric-to-electric efficiency can more accurately reflect the actual efficiency of the system.

[0063] 2. The prior art assumes that the air mass flow rate during compression and expansion is known and constant during operation; however, the present invention assumes that the turbine operates in a throttling + air supply mode, and the air flow rate is not a constant value, which is closer to the actual operating conditions and improves the accuracy of the electric-to-electric efficiency calculation.

[0064] 3. The present invention fully considers factors such as air pressure loss, heat exchange temperature drop, etc. in each link during actual operation, is closer to actual operating conditions, and improves the accuracy of electric-electric efficiency calculation.

[0065] 4. The present invention also takes into account the power consumption of auxiliary equipment during compression, expansion and system shutdown, which is closer to actual operating conditions and improves the accuracy of electric-to-electric efficiency calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a flow chart of the present invention;

[0067] Figure 2 is a schematic diagram of a compressed air energy storage system;

[0068] Figure 3 is the variation of the actual power consumption of the last compression cylinder with the exhaust pressure;

[0069] Figure 4 It is a schematic diagram of the air flow curve of the turbine unit. DETAILED DESCRIPTION

[0070] The present invention will be described in more detail below with reference to the embodiments.

[0071] Example 1

[0072] like Figure 2As shown, a compressed air energy storage system includes a compression unit, a heat exchange unit, a heat storage unit, a turbine unit, a cooling unit, and an air storage unit. The compression unit includes a compressor, which includes several compression cylinders and valves and pipes connected thereto; the heat exchange unit includes several heat exchangers on the compression side and several heat exchangers on the turbine side and valves and pipes connected thereto; the heat storage unit includes a high-temperature heat storage device (such as a high-temperature water storage tank), a low-temperature heat storage device (such as a low-temperature water storage tank), and pumps, valves, and pipes connected thereto; the turbine unit includes a turbine, which includes several turbine cylinders and valves and pipes connected thereto; the cooling unit includes a cooling tower and valves and pipes connected thereto; and the air storage unit includes an air storage chamber and valves and pipes connected thereto.

[0073] The air inlet of the first-stage compression cylinder is connected to the atmosphere via an air duct. Air ducts connect every two compression cylinders in series with the air side of the compression-side heat exchanger and the air side of the radiator. The air outlet of the last-stage compression cylinder is connected in series with the air side of the compression-side heat exchanger and the air inlet of the air storage chamber. The air inlet of the first-stage turbine cylinder is connected in series with the air side of the turbine heat exchanger and the air outlet of the air storage chamber. Air ducts connect the turbine cylinders in series with the air side of the turbine heat exchanger. The air outlet of the last-stage turbine cylinder is connected to the atmosphere via an air duct. The inlets of the high-temperature heat storage device are connected to the water-side outlets of the compression-side heat exchanger, which are connected to a main pipe through branch pipes. The outlets of the high-temperature heat storage device are connected to the water-side inlets of the turbine-side heat exchanger, which are connected to a main pipe through branch pipes. The outlets of the low-temperature heat storage device are connected to the water-side inlets of the compression-side heat exchanger, which are connected to a main pipe through branch pipes. The inlets of the low-temperature heat storage device are connected to the water-side outlets of the turbine-side heat exchanger, which are connected to a main pipe through branch pipes. The water side inlet of the radiator is connected to the outlet of the cooling tower through branch pipes into a main pipe, and the water side outlet of the radiator is connected to the inlet of the cooling tower through branch pipes into a main pipe.

[0074] Example 2

[0075] like Figure 1 As shown, the method for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state includes the following steps:

[0076] Get the turbine unit operating output W t .

[0077] Get the compression unit air flow q c .

[0078] Get the power consumption W of the compression unit c .

[0079] Get the turbine unit air flow q t .

[0080] Based on the deviation between the heat storage medium flow rate on the compression side and the heat storage medium flow rate on the turbine side, as well as the deviation between the air flow rate of the compression unit and the air flow rate of the turbine unit, it is judged whether the compressed air energy storage system is in a balanced operating condition, specifically including:

[0081] Based on the operating parameters, the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate are calculated; based on the deviation between the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate, and the deviation between the compression unit air flow rate and the turbine unit air flow rate, a balance index is calculated; if the balance index is not within a preset range, it is considered that the compressed air energy storage system is not in a balanced operating condition, and the operating parameters are reset until the compressed air energy storage system reaches a balanced operating condition.

[0082] Calculate the turbine unit operating time t in one cycle t The corresponding total gas consumption q t_total According to the total gas consumption of the turbine unit q t_total and compression unit air flow q c , calculate the compression unit running time t in a cycle c .

[0083] According to the turbine unit operating time t in one cycle t And turbine unit operating output W t , calculate the system output energy; according to the compression unit running time t in a cycle c And the compression unit power consumption W c , calculate the system input energy; based on the system input energy and system output energy, calculate the system electrical-electrical efficiency.

[0084] Example 3

[0085] A method for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state includes the following steps:

[0086] S1: Obtain the initial environmental parameters of the compressed air energy storage system, including the daytime temperature T 0_day , daytime air pressure P 0_day , daytime humidity RH day , night temperature T 0_night , nighttime air pressure P 0_night , night humidity RH niqht and other parameters.

[0087] Obtain the design parameters of the compressed air energy storage system, including the output W of the turbine unit t 、Number of compression cylinders n c , compression unit air flow q c 、Number of turbine cylinders n t and other parameters.

[0088] S2: Based on the initial environmental parameters, the operating parameters of the compression unit are obtained, including the inlet and outlet air temperature and pressure of each compression cylinder, and the actual power consumption of the compression cylinder under variable operating conditions.

[0089] Calculate the actual power consumption of the i-th compression cylinder and express it as follows:

[0090]

[0091] Where W c_i is the actual power consumption of the i-th compression cylinder; η c_d is the motor efficiency of the i-th compression cylinder.

[0092] Calculate the power consumption of the compression unit and express it as follows:

[0093]

[0094] Where n c Indicates the number of compression cylinders.

[0095] S3: Set the initial heat exchange end difference of the heat exchanger; specifically, set the upper end difference of the heat exchanger to Δ u , the lower end difference is Δ d .

[0096] S4: Based on the difference between the upper and lower ends of the heat exchanger, obtain the turbine unit operating parameters under variable operating conditions, including the turbine unit air flow q t , turbine cylinder air inlet and outlet temperatures, etc. In this embodiment, the turbine unit adopts a throttling + air supply operation mode, that is, in the initial operating state, the turbine unit air flow rate remains constant. When the turbine unit inlet air pressure drops to a certain level, the air supply valve opens, and the turbine unit air flow rate gradually increases over time.

[0097] S5: Determine whether the heat and gas volume are balanced after the compressed air energy storage system runs for one cycle; if not, return to S3 and reset the initial end difference of the heat exchanger; if balanced, continue to S6.

[0098] S51. Calculate the balance index:

[0099] Calculate parameters such as heat storage medium temperature, heat storage medium flow rate, enthalpy value, etc. under variable working conditions.

[0100] The temperature of the heat storage medium in the compression side heat exchanger can be calculated as follows:

[0101] T chx_w_out_i =T chx_a_in_i -Δ u

[0102] Where, T chx_a_in_i represents the air inlet temperature of the i-th compression side heat exchanger; T chx_w_out_irepresents the outlet temperature of the heat storage medium of the i-th compression side heat exchanger.

[0103] T chx_w_in_i =T chx_a_out_i -Δ d

[0104] Where, T chx_a_out_i represents the air outlet temperature of the i-th compression side heat exchanger; T chx_w_in_d represents the inlet temperature of the heat storage medium of the i-th compression side heat exchanger.

[0105] The air inlet parameters of the compression side heat exchanger are associated with the exhaust parameters of the compression cylinder connected thereto, and the air inlet parameters of the compression cylinder are associated with the air outlet parameters of the compression side heat exchanger connected thereto.

[0106] Enthalpy value h is a function of temperature T, that is, enthalpy value h can be obtained by looking up the enthalpy entropy table of air and water according to temperature T. chx_a_in_i 、T chx_a_out_i 、T chx_w_out_i 、T chx_w_in_i Query the air enthalpy entropy table and water enthalpy entropy table to obtain h chx_a_in_i 、h chx_a_out_i 、h chx_w_out_i 、h chx_w_in_i Among them, T chx_a_oin_i 、T chx_a_out_i 、T chx_w_out_i 、T chx_w_in_i are the air inlet temperature of the ith compression side heat exchanger, the air outlet temperature of the dth compression side heat exchanger, the heat storage medium outlet temperature of the ith compression side heat exchanger, and the heat storage medium inlet temperature of the ith compression side heat exchanger; h chx_a_in_i represents the air inlet enthalpy of the i-th compression side heat exchanger, h chx_a_out_i represents the air outlet enthalpy of the i-th compression side heat exchanger, h chx_w_out_i represents the outlet enthalpy of the heat storage medium of the i-th compression side heat exchanger, h chx_w_in_i represents the inlet enthalpy of the heat storage medium of the i-th compression side heat exchanger.

[0107] Calculate the heat storage medium flow rate q of the compression side heat exchanger c_w_i , expressed as:

[0108] q c_w_i =(h chx_a_in_i -h chx_a_out_i )q c η hx / (h chx_w_out_i -h chx_w_in_i )

[0109] Among them, q c is the air flow rate of the compression unit, η hxIndicates the heat transfer efficiency of the heat exchanger.

[0110] During the heat storage process, the heat storage medium of different compression side heat exchangers is finally collected into the high temperature heat storage device. The enthalpy value of the heat storage medium in the high temperature heat storage device is calculated and expressed as follows:

[0111]

[0112] Among them, h sto is the enthalpy of the heat storage medium in the high-temperature heat storage device.

[0113] Temperature T is a function of enthalpy value h, that is, temperature T can be obtained by looking up the enthalpy entropy table of air and water according to enthalpy value h. sto Look up the enthalpy and entropy tables of air and water to obtain T sto Among them, T sto is the temperature of the heat storage medium in the high-temperature heat storage device.

[0114] The parameters of the heat storage medium in the high-temperature heat storage device are associated with the heat storage medium inlet parameters of the turbine side heat exchanger.

[0115] The temperature of the heat storage medium in the turbine side heat exchanger can be calculated as follows:

[0116] T thx_w_out_i =T thx_a_in_i +Δ d

[0117] Where, T thx_a_in_i represents the air inlet temperature of the i-th turbine side heat exchanger; T thx_w_out_i represents the outlet temperature of the heat storage medium of the i-th turbine side heat exchanger.

[0118] T thx_w_in_i =T thx_a_out_i +Δ u

[0119] Where, T thx_a_out_i represents the air outlet temperature of the i-th turbine side heat exchanger; T thx_w_in_i represents the inlet temperature of the heat storage medium of the i-th turbine side heat exchanger.

[0120] The air outlet parameters of the turbine side heat exchanger are associated with the air intake parameters of the turbine cylinder connected thereto, and the air outlet parameters of the turbine cylinder are associated with the air inlet parameters of the turbine side heat exchanger connected thereto.

[0121] Enthalpy value h is a function of temperature T, that is, enthalpy value h can be obtained by looking up the enthalpy entropy table of air and water according to temperature T. thx_a_in_i 、T thx_a_out_i 、T thx_w_out_i 、T thx_w_in_i Query the air enthalpy entropy table and water enthalpy entropy table to obtain h thx_a_in_i、h thx_a_out_i 、h thx_w_out_i 、h thx_w_in_i Among them, T thx_a_in_i 、T thx_a_out_i 、T thx_w_out_i 、T thx_w_in_i are the air inlet temperature of the ith turbine side heat exchanger, the air outlet temperature of the ith turbine side heat exchanger, the heat storage medium outlet temperature of the ith turbine side heat exchanger, and the heat storage medium inlet temperature of the ith turbine side heat exchanger; h thx_a_in_i represents the air inlet enthalpy of the i-th turbine side heat exchanger, h thx_a_out_i represents the air outlet enthalpy of the i-th turbine side heat exchanger, h thx_w_out_i represents the outlet enthalpy of the heat storage medium of the i-th turbine side heat exchanger, h thx_w_in_i represents the inlet enthalpy of the heat storage medium of the i-th turbine side heat exchanger.

[0122] Calculate the heat storage medium flow rate on the turbine side of the turbine side heat exchanger, expressed as follows:

[0123] q t_w_i =(h thx_a_in_i -h thx_a_out_i )q t / [(h thx_w_out_i -h thx_w_in_i )η hx ]

[0124] Among them, h thx_a_in_i represents the air inlet enthalpy of the i-th turbine side heat exchanger, h thx_a_out_i represents the air outlet enthalpy of the i-th turbine side heat exchanger, q t is the air flow rate of the turbine unit, η hx Indicates the heat transfer efficiency of the heat exchanger, h thx_w_out_i represents the outlet enthalpy of the heat storage medium of the i-th turbine side heat exchanger, h thx_w_in_i represents the inlet enthalpy of the heat storage medium of the i-th turbine side heat exchanger.

[0125] Calculate the balance indicator, expressed as the formula:

[0126]

[0127] Where n c is the number of compression cylinders; n t is the number of turbine cylinders; q c_w_i is the heat storage medium flow rate in the i-th compression side heat exchanger; q t_w_i is the heat storage medium flow rate in the i-th turbine side heat exchanger; q c is the air flow rate of the compression unit; q t is the air flow of the turbine unit.

[0128] If the balance index E is within the preset range, the compressed air energy storage system is considered to be in a balanced working condition.

[0129] S6: Calculate the total gas consumption of the turbine unit during the entire compressed air energy storage system process, expressed as follows:

[0130]

[0131] Where, t t It is the operating time of the turbine unit in one cycle.

[0132] S7: Calculate the operating time of the compression unit of the compressed air energy storage system, expressed as follows:

[0133]

[0134] Where, t c The running time of the compression unit in one cycle.

[0135] S8: Calculate the downtime of the compressed air energy storage system in one cycle, expressed as:

[0136] t s =24-t t -t c

[0137] Where, t s It represents the downtime of a compressed air energy storage system in one cycle. In this embodiment, the cycle is one day.

[0138] S8: Calculate the electric-electric efficiency of the compressed air energy storage system, expressed as:

[0139]

[0140] Where, ε c , ε t , ε s Respectively represent the power consumption of auxiliary equipment during the operation of the compression unit, the operation of the turbine unit, and the system shutdown process of the compressed air energy storage system; t Indicates the operating output of the turbine unit; t t Indicates the operating time of the turbine unit in one cycle; W c Indicates the power consumption of the compression unit; t c Indicates the running time of the compression unit in one cycle; t s Indicates the downtime of a compressed air energy storage system in one cycle.

[0141] Example 4

[0142] Taking a practical example, the electric-to-electric efficiency of compressed air energy storage is calculated as follows:

[0143] S1: Get the initial environmental parameters as follows: daytime temperature T 0_day =21.4℃, daytime air pressure P 0_day =955.2hPa, daytime humidity RH day =72.7%, night temperature T 0_night =16.3℃, nighttime air pressure P 0_night =955.4hPa, night humidity RH night =94.8%.

[0144] The design parameters of the compressed air energy storage system are as follows: the operating output of the turbine unit is 300MW, the number of compression cylinders is n c =4, compression unit air flow q c =800t / h, number of turbine cylinders n t =4.

[0145] S2: According to the initial environmental parameters, the compression unit operating parameters are obtained, as shown in Table 1.

[0146] Table 1

[0147]

[0148] Note: The compression cylinder numbers 1 to 3 represent the operating parameters of the 1st to 3rd compression cylinders, the compression cylinder number 4a represents the operating parameters when the 4th compression cylinder starts to operate, and the compression cylinder number 4b represents the operating parameters when the 4th compression cylinder ends to operate. The actual power consumption of the 4th (last) compression cylinder changes with the exhaust pressure as shown in the figure below. Figure 3 shown.

[0149] S3: Set the initial heat exchange end difference of the heat exchanger.

[0150] Set the upper end difference of the heat exchanger to Δ u =15℃, the lower end difference is Δ d =10℃.

[0151] S4: Based on the difference between the upper and lower ends of the heat exchanger, the operating parameters of the turbine unit under variable working conditions are obtained as follows: The initial air flow rate of the turbine unit q t =2294.64t / h, the turbine unit adopts the throttling + air supply operation mode, that is, the air flow of the turbine unit is constant in the initial operation state. When the pressure drops to a certain level, the air supply valve opens, and the air flow of the turbine unit gradually increases over time. The air flow of the turbine unit changes with time, such as Figure 4 The inlet and outlet temperatures of the turbine cylinder air are 160°C and 40°C respectively.

[0152] S5: Determine whether the heat and gas volume of the compressed air energy storage system are balanced after one cycle. If not, return to S3. If balanced, continue to S6. The compression side balance calculation results are shown in Table 2:

[0153] Table 2

[0154]

[0155]

[0156] Note a: Indicates the parameters when the compressor starts running / the parameters when the compressor ends running.

[0157] The heat storage enthalpy is calculated as

[0158]

[0159] Query the enthalpy entropy table of water to obtain the temperature T of the heat storage medium in the high-temperature heat storage device sto =175℃

[0160] The results of turbine side balance calculation are shown in Table 3:

[0161] Table 3

[0162]

[0163] Calculate the equilibrium state index:

[0164]

[0165] If the balance index E is within the preset range (0.99 to 1.01), the compressed air energy storage system is considered to be in a balanced working condition.

[0166] Reach equilibrium and enter S6.

[0167] S6: Assuming the turbine unit operation time in one cycle is 6 hours, calculate the total gas consumption of the turbine unit in the entire process of the compressed air energy storage system

[0168]

[0169] S7: Calculate the operating time of the compression unit system in one cycle of the compressed air energy storage system

[0170]

[0171] S8: Calculate the electric-electric efficiency of the compressed air energy storage system

[0172] Compressed air energy storage system calculates downtime in a cycle:

[0173] t s=24-t t -t c =8.96h

[0174] In this embodiment, the cycle period is one day.

[0175] Calculate the electric-electric efficiency of the compressed air energy storage system:

[0176]

[0177] It should be noted that the above-mentioned compressed air energy storage electric-electric efficiency calculation device based on equilibrium state is also used to implement the method steps corresponding to each embodiment in the above-mentioned compressed air energy storage electric-electric efficiency calculation method based on equilibrium state, and this application will not repeat them here.

[0178] It should be noted that the functional units / modules in the various embodiments of the present invention may be integrated into a single processing unit / module, each unit / module may exist physically separately, or two or more units / modules may be integrated into a single unit / module. The aforementioned integrated units / modules may be implemented in the form of hardware or software functional units / modules.

[0179] Through the description of the above embodiments, it will be clear to those skilled in the art that the embodiments described herein can be implemented in hardware, software, firmware, middleware, code, or any appropriate combination thereof. For hardware implementation, the processor can be implemented in one or more of the following units: an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microcontroller, a microprocessor, other electronic units designed to implement the functions described herein, or a combination thereof. For software implementation, part or all of the processes of the embodiments can be completed by instructing the relevant hardware through a computer program. During implementation, the above program can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transmission of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a computer. Computer-readable media can include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer.

[0180] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should analyze that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state, characterized in that: The following steps are involved: Get the turbine unit operating output W t ; Get the compression unit air flow q c ; Get the power consumption W of the compression unit c ; Get the turbine unit air flow q t ; Determine whether the compressed air energy storage system is in a balanced operating condition based on the deviation between the heat storage medium flow rate on the compression side and the heat storage medium flow rate on the turbine side, and the deviation between the air flow rate of the compression unit and the air flow rate of the turbine unit; If the compressed air energy storage system is not in a balanced operating condition, adjust the compressed air energy storage system to a balanced operating condition; Calculate the turbine unit operating time t in one cycle t The corresponding total gas consumption q t_total According to the total gas consumption of the turbine unit q t_total and compression unit air flow q c , calculate the compression unit running time t in a cycle c ; According to the turbine unit operating time t in one cycle t And turbine unit operating output W t , calculate the system output energy; according to the compression unit running time t in a cycle c And the compression unit power consumption W c , calculate the system input energy; Calculate the system electrical-electrical efficiency based on the system input energy and system output energy; Also includes: Calculate the downtime t of the compressed air energy storage system in a cycle s ; Calculate the downtime t of the compressed air energy storage system in a cycle s The corresponding auxiliary equipment consumes energy; Calculate the compression unit running time t in one cycle c The corresponding auxiliary equipment consumes energy; Calculate the turbine unit operating time t in one cycle t The corresponding auxiliary equipment consumes energy; Correct the system output energy and system input energy according to the energy consumed by the auxiliary equipment; Calculate the system electrical-electrical efficiency based on the corrected system output energy and system input energy; The calculation system electric-electric efficiency is expressed as follows: Where, ε c , ε t , ε s Respectively represent the power consumption of auxiliary equipment during the operation of the compression unit, the operation of the turbine unit, and the system shutdown process of the compressed air energy storage system; W t Indicates the operating output of the turbine unit; t t Indicates the operating time of the turbine unit in one cycle; W c Indicates the power consumption of the compression unit; t c Indicates the running time of the compression unit in one cycle; t s Indicates the downtime of a compressed air energy storage system in one cycle.

2. The method for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state according to claim 1, characterized in that: The compressed air energy storage system is adjusted to a balanced operating condition, specifically: Obtaining operating parameters of the compressed air energy storage system, wherein the operating parameters include a heat exchange end difference of a heat exchanger; Based on the operating parameters, the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate are calculated; based on the deviation between the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate, and the deviation between the compression unit air flow rate and the turbine unit air flow rate, a balance index is calculated; if the balance index is not within a preset range, it is considered that the compressed air energy storage system is not in a balanced operating condition, and the operating parameters are reset until the compressed air energy storage system reaches a balanced operating condition.

3. The method for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state according to claim 2, characterized in that: The calculation balance index is expressed as follows: Where n c is the number of compression cylinders; n t is the number of turbine cylinders; q c_w_i is the heat storage medium flow rate in the i-th compression side heat exchanger; q t_w_i is the heat storage medium flow rate in the i-th turbine side heat exchanger; q c is the air flow rate of the compression unit; q t is the air flow of the turbine unit.

4. The method for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state according to claim 2, characterized in that: The calculation of the compression side heat storage medium flow rate and the turbine side heat storage medium flow rate is specifically as follows: Calculate the heat storage medium temperature based on the heat exchange end difference; obtain the heat storage medium enthalpy value based on the heat storage medium temperature; calculate the heat storage medium flow rate in the compression side heat exchanger based on the heat storage medium enthalpy value and the compression unit air flow rate; The heat storage medium flow rate in the turbine side heat exchanger is calculated based on the heat storage medium enthalpy value and the turbine unit air flow rate.

5. A device for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state, characterized in that: The system comprises a memory and a processor, wherein the memory stores instructions, and the instructions are suitable for being loaded by the processor and executing the following steps: Get the turbine unit operating output W t ; Get the compression unit air flow q c ; Get the power consumption W of the compression unit c ; Get the turbine unit air flow q t ; Determine whether the compressed air energy storage system is in a balanced operating condition based on the deviation between the heat storage medium flow rate on the compression side and the heat storage medium flow rate on the turbine side, and the deviation between the air flow rate of the compression unit and the air flow rate of the turbine unit; If the compressed air energy storage system is not in a balanced operating condition, adjust the compressed air energy storage system to a balanced operating condition; Calculate the turbine unit operating time t in one cycle t The corresponding total gas consumption q t_total According to the total gas consumption of the turbine unit q t_total and compression unit air flow q c , calculate the compression unit running time t in a cycle c ; According to the turbine unit operating time t in one cycle t And turbine unit operating output W t , calculate the system output energy; according to the compression unit running time t in a cycle c And the compression unit power consumption W c , calculate the system input energy; Calculate the system electrical-electrical efficiency based on the system input energy and system output energy; Also includes: Calculate the downtime t of the compressed air energy storage system in a cycle s ; Calculate the downtime t of the compressed air energy storage system in a cycle s The corresponding auxiliary equipment consumes energy; Calculate the compression unit running time t in one cycle c The corresponding auxiliary equipment consumes energy; Calculate the turbine unit operating time t in one cycle t The corresponding auxiliary equipment consumes energy; Correct the system output energy and system input energy according to the energy consumed by the auxiliary equipment; Calculate the system electrical-electrical efficiency based on the corrected system output energy and system input energy; The calculation system electric-electric efficiency is expressed as follows: Where, ε c , ε t , ε s Respectively represent the power consumption of auxiliary equipment during the operation of the compression unit, the operation of the turbine unit, and the system shutdown process of the compressed air energy storage system; W t Indicates the operating output of the turbine unit; t t Indicates the operating time of the turbine unit in one cycle; W c Indicates the power consumption of the compression unit; t c Indicates the running time of the compression unit in one cycle; t s Indicates the downtime of a compressed air energy storage system in one cycle.

6. The device for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state according to claim 5, characterized in that: The compressed air energy storage system is adjusted to a balanced operating condition, specifically: Obtaining operating parameters of the compressed air energy storage system, wherein the operating parameters include a heat exchange end difference of a heat exchanger; Based on the operating parameters, the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate are calculated; based on the deviation between the compression-side heat storage medium flow rate and the turbine-side heat storage medium flow rate, and the deviation between the compression unit air flow rate and the turbine unit air flow rate, a balance index is calculated; if the balance index is not within a preset range, it is considered that the compressed air energy storage system is not in a balanced operating condition, and the operating parameters are reset until the compressed air energy storage system reaches a balanced operating condition.

7. The device for calculating the electric-electric efficiency of compressed air energy storage based on equilibrium state according to claim 6, characterized in that: The calculation of the compression side heat storage medium flow rate and the turbine side heat storage medium flow rate is specifically as follows: Calculate the temperature of the heat storage medium according to the heat exchange end difference; obtain the enthalpy value of the heat storage medium according to the temperature of the heat storage medium; Calculate the heat storage medium flow rate in the compression side heat exchanger based on the heat storage medium enthalpy value and the air flow rate of the compression unit; The heat storage medium flow rate in the turbine side heat exchanger is calculated based on the heat storage medium enthalpy value and the turbine unit air flow rate.

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