Building load fluctuation analysis method based on distributed energy system

Abstract

The present invention discloses a building load volatility analysis method based on a distributed energy system, including the determination of constraint conditions, wherein the determination of the constraint conditions includes the determination of energy balance conditions and the determination of equipment capacity constraints; the energy balance condition refers to the energy provided by each device of the system under a prescribed operation strategy can meet the user's demand for cooling, heating and electricity, and the determination of the equipment capacity constraints selects a gas turbine as a power generation unit of an optimization model, and the capacity of the gas turbine is ζ gt.E As a variable optimized by the algorithm, the capacity of the gas turbine determines the capacity of the waste heat boiler and the absorption refrigeration unit. The capacity of the gas boiler is determined by the capacity and heat load data of the gas turbine. The gas boiler needs to meet the maximum heating demand when the heating supply of the gas turbine is insufficient. The equipment capacity of the electric refrigeration unit is determined by the equipment capacity and cold load demand of the absorption refrigeration unit. The present invention has the characteristics of strong practicality.

Description

Technical Field

[0001] The present invention relates to the technical field of building load characteristics, and in particular to a building load volatility analysis method based on a distributed energy system. Background Art

[0002] At present, there have been a lot of studies on the optimization of distributed energy system operation strategies and economic costs, but the preliminary building load analysis is often not accurate enough, which may lead to deviations in the optimization results. Therefore, it is necessary to design a practical building load volatility analysis method based on distributed energy systems. Summary of the invention

[0003] The purpose of the present invention is to provide a building load volatility analysis method based on a distributed energy system to solve the problems raised in the above background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: a building load volatility analysis method based on a distributed energy system, including determination of constraint conditions, wherein the determination of the constraint conditions includes determination of energy balance conditions and determination of equipment capacity constraints;

[0005] The energy balance condition refers to the energy provided by each device in the system under the specified operation strategy can meet the user's demand for cooling, heating and electricity. The determination of the equipment capacity constraint selects the gas turbine as the power generation unit of the optimization model, and the capacity of the gas turbine is used as the variable of the algorithm optimization. Determines the capacity of the waste heat boiler and absorption refrigeration unit.

[0006] According to the above technical solution, the energy balance condition is as follows:

[0007] ;

[0008] In the formula, , , They refer to the hourly power supply of the municipal power grid, the hourly power generation of the gas turbine, and the hourly power consumption of the electric refrigeration unit in the DES system; , They refer to the hourly cooling capacity of electric refrigeration units and absorption refrigeration units respectively; , They refer to the hourly heating capacity of waste heat boilers and gas boilers respectively; , , Respectively refer to the user's hourly electricity, cooling and heating load values. is the efficiency of the waste heat boiler.

[0009] According to the above technical solution, the equipment capacity constraints are specifically as follows:

[0010] ;

[0011] In the formula, , , , refer to the rated heating capacity of the gas turbine, the rated power generation of the gas turbine, the rated capacity of the waste heat boiler, and the rated capacity of the absorption refrigeration unit respectively; , They refer to the efficiency of waste heat boiler and absorption refrigeration unit respectively. The ratio of heat supplied to the gas turbine to electricity generated;

[0012] The capacity of the gas boiler is determined by the capacity and heat load data of the gas turbine. The gas boiler needs to meet the maximum heating demand when the heat supply of the gas turbine is insufficient. Specifically:

[0013] ;

[0014] In the formula, Refers to the rated capacity of the gas boiler; Refers to the hourly heating amount of the gas turbine;

[0015] The equipment capacity of the electric refrigeration unit is determined by the equipment capacity of the absorption refrigeration unit and the cooling load demand, specifically:

[0016] ;

[0017] In the formula, Refers to the rated capacity of the electric refrigeration unit. Refers to the hourly cooling capacity of the gas turbine.

[0018] According to the above technical solution, the device model is also established, and the establishment of the device model includes:

[0019] The output thermal efficiency and electrical efficiency of the gas turbine are determined by the load rate. The calculation formula is:

[0020] ;

[0021] The discrete data of gas turbine operating efficiency is fitted, and the fitting function expression is:

[0022] ;

[0023] From the above gas turbine load factor The thermal efficiency fitting function can calculate the hourly operating efficiency of the gas turbine and the hourly gas consumption of the gas turbine:

[0024] ;

[0025] In the formula, , They refer to the rated power generation and the rated heating capacity of the gas turbine respectively; Refers to the calorific value of natural gas;

[0026] Waste heat boiler unit model: ;

[0027] In the formula, Refers to the hourly heating amount of the waste heat boiler;

[0028] Gas boiler model: ;

[0029] In the formula, Refers to the heating capacity of gas boiler. Refers to the amount of natural gas consumed by gas boilers hourly;

[0030] Electric refrigeration unit: ;

[0031] In the formula, Refers to the hourly cooling capacity of the electric refrigeration unit. Refers to the hourly power consumption of electric refrigeration units; Refers to the refrigeration COP of the electric refrigeration unit;

[0032] Absorption refrigeration unit model: .

[0033] According to the above technical solution, including the formulation of DES operation strategy:

[0034] Based on the operating efficiency of the above equipment, the operating strategies under different seasons and different load demand characteristics are discussed in detail:

[0035] A: In winter and load ratio > ; < When the power supply is insufficient, the power grid will provide the power for the insufficient load.

[0036] B: In winter and load ratio > ; > When the gas turbine runs at rated power, the insufficient heat and electricity loads are provided by the gas boiler and the power grid;

[0037] C: In winter and load ratio < ; > When the heat load is insufficient, the gas boiler will be used to provide the insufficient heat load.

[0038] D: In summer and load ratio > ; < When the power is low, the cold-power operation mode is adopted, and the insufficient power load demand is provided by the power grid;

[0039] E: In summer and load ratio > ; > When the gas turbine runs at full load, the insufficient cooling load and electrical load are provided by the electric refrigeration unit and the power grid respectively;

[0040] F: In summer and load ratio < When the load factor of the gas turbine is for

[0041] At this time, the gas turbine can just meet all the user's electrical load and cooling load requirements for the system.

[0042] According to the above technical solution, an evaluation index method is also included. The evaluation index method comprehensively considers economic, environmental and energy efficiency factors, and compares the annual total cost and annual total cost saving rate, primary energy utilization efficiency, Emissions and The emission reduction rate is used as an evaluation indicator;

[0043] Annual operating cost of the distribution system and DES annual cost savings The expression is:

[0044] ;

[0045] In the formula, , They refer to hourly electricity prices and natural gas unit prices respectively; , They respectively refer to the hourly electricity consumption of the distribution system and the hourly natural gas consumption of the distribution system.

[0046] According to the above technical solution, in the above evaluation index method, the primary energy utilization efficiency The evaluation index expression is:

[0047] ;

[0048] In the formula, It is the hourly primary energy consumption of DES.

[0049] According to the above technical solution, in the above evaluation index method, the annual The emission expression is:

[0050] ;

[0051] ;

[0052] In the formula, The carbon dioxide produced per kilowatt-hour of electricity generated by a power plant; is the amount of carbon dioxide produced by burning a unit volume of natural gas; , , , They respectively refer to the amount of electricity purchased by the DES system from the power grid, the amount of natural gas consumed by the DES system hourly, the amount of electricity purchased by the distribution system from the power grid, and the amount of natural gas consumed by the distribution system.

[0053] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention provides a reference for the design and optimization of distributed energy systems by comparing and analyzing the impact of the building's annual cooling and heating load fluctuations on the distributed energy system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0055] Figure 1 The discrete data of the gas turbine operating efficiency of the present invention is used to fit the curve;

[0056] Figure 2 It is a schematic diagram of the load of each unit of the present invention;

[0057] Figure 3 is a schematic diagram of the dispersion of the load data set of the present invention;

[0058] Figure 4 It is a schematic diagram of the correlation coefficient of discrete composite data of the present invention. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] See also Figure 1-4 , the present invention provides a technical solution: a building load volatility analysis method based on a distributed energy system, including the determination of constraint conditions, the determination of constraint conditions including the determination of energy balance conditions and the determination of equipment capacity constraints;

[0061] The energy balance condition means that the energy provided by each device in the system under the specified operation strategy can meet the user's demand for cooling, heating and electricity. The determination of equipment capacity constraints selects gas turbines as the power generation unit of the optimization model. The capacity of the gas turbine As the variable optimized by the algorithm, the capacity of the gas turbine determines the capacity of the waste heat boiler and the absorption chiller;

[0062] The energy balance conditions are as follows:

[0063] ;

[0064] In the formula, , , They refer to the hourly power supply of the municipal power grid, the hourly power generation of the gas turbine, and the hourly power consumption of the electric refrigeration unit in the DES system; , They refer to the hourly cooling capacity of electric refrigeration units and absorption refrigeration units respectively; , They refer to the hourly heating capacity of waste heat boilers and gas boilers respectively; , , Respectively refer to the user's hourly electricity, cooling and heating load values. is the efficiency of the waste heat boiler;

[0065] The equipment capacity constraints are as follows:

[0066] ;

[0067] In the formula, , , , They refer to the rated heating capacity of the gas turbine, the rated power generation of the gas turbine, the rated capacity of the waste heat boiler, and the rated capacity of the absorption refrigeration unit respectively; , They refer to the efficiency of waste heat boiler and absorption refrigeration unit respectively. The ratio of heat supplied to the gas turbine to electricity generated;

[0068] The capacity of the gas boiler is determined by the capacity and heat load data of the gas turbine. The gas boiler needs to meet the maximum heating demand when the heat supply of the gas turbine is insufficient. Specifically:

[0069] ;

[0070] In the formula, Refers to the rated capacity of the gas boiler; Refers to the hourly heating amount of the gas turbine;

[0071] The equipment capacity of the electric refrigeration unit is determined by the equipment capacity of the absorption refrigeration unit and the cooling load demand, specifically:

[0072] ;

[0073] In the formula, Refers to the rated capacity of the electric refrigeration unit. Refers to the hourly cooling capacity of the gas turbine;

[0074] It also includes the establishment of the equipment model, which includes:

[0075] The output thermal efficiency and electrical efficiency of the gas turbine are determined by the load rate. The calculation formula is:

[0076] ;

[0077] The discrete data of gas turbine operating efficiency is fitted, and the fitting function expression is:

[0078] ;

[0079] From the above gas turbine load factor The thermal efficiency fitting function can calculate the hourly operating efficiency of the gas turbine and the hourly gas consumption of the gas turbine:

[0080] ;

[0081] In the formula, , They refer to the rated power generation and the rated heating capacity of the gas turbine respectively; Refers to the calorific value of natural gas;

[0082] Waste heat boiler unit model: ;

[0083] In the formula, Refers to the hourly heating amount of the waste heat boiler;

[0084] Gas boiler model: ;

[0085] In the formula, Refers to the heating capacity of gas boiler. Refers to the amount of natural gas consumed by gas boilers hourly;

[0086] Electric refrigeration unit: ;

[0087] In the formula, Refers to the hourly cooling capacity of the electric refrigeration unit. Refers to the hourly power consumption of electric refrigeration units; Refers to the refrigeration COP of the electric refrigeration unit;

[0088] Absorption refrigeration unit model: ;

[0089] Including the formulation of DES operation strategy:

[0090] Based on the operating efficiency of the above equipment, the operating strategies under different seasons and different load demand characteristics are discussed in detail:

[0091] A: In winter and load ratio > ; < When the power supply is insufficient, the power grid will provide the power for the insufficient load.

[0092] B: In winter and load ratio > ; > When the gas turbine runs at rated power, the insufficient heat and electricity loads are provided by the gas boiler and the power grid;

[0093] C: In winter and load ratio < ; > When the heat load is insufficient, the gas boiler will be used to provide the insufficient heat load.

[0094] D: In summer and load ratio > ; < When the power is low, the cold-power operation mode is adopted, and the insufficient power load demand is provided by the power grid;

[0095] E: In summer and load ratio > ; > When the gas turbine runs at full load, the insufficient cooling load and electrical load are provided by the electric refrigeration unit and the power grid respectively;

[0096] F: In summer and load ratio < When the load factor of the gas turbine is for

[0097] , at this time, the gas turbine can just meet all the user's electrical load and cooling load requirements for the system;

[0098] It also includes an evaluation index method, which comprehensively considers economic, environmental and energy efficiency factors, and compares the annual total cost and annual total cost saving rate, primary energy utilization efficiency, Emissions and The emission reduction rate is used as an evaluation indicator;

[0099] Annual operating cost of the distribution system and DES annual cost savings The expression is:

[0100] ;

[0101] In the formula, , They refer to hourly electricity prices and natural gas unit prices respectively; , They refer to the hourly electricity consumption of the distribution system and the hourly natural gas consumption of the distribution system respectively;

[0102] In the above evaluation index method, primary energy efficiency The evaluation index expression is:

[0103] ;

[0104] In the formula, The hourly primary energy consumption of DES;

[0105] In the above evaluation index method, the annual The emission expression is:

[0106] ;

[0107] ;

[0108] In the formula, The carbon dioxide produced per kilowatt-hour of electricity generated by a power plant; is the amount of carbon dioxide produced by burning a unit volume of natural gas; , , , They respectively refer to the amount of electricity purchased by the DES system from the power grid, the amount of natural gas consumed by the DES system hourly, the amount of electricity purchased by the distribution system from the power grid, and the amount of natural gas consumed by the distribution system.

[0109] Example: To verify the above theory, this paper takes an office building in Nanjing as an example, with a building area of ​​about 20,000 square meters, and performs simulation optimization calculation. The load data of the building is obtained by DeST simulation software, and the cooling and heating loads of the building are discretized using Matlab software to obtain 100 sets of discrete load data. Figure 2 Taking the original load of the building (group B) and its two groups of discrete loads (groups A and C) as examples, the delay curves of the cooling, heating and electricity loads are shown: The volatility variance of the discrete load data is as follows: Figure 3 Shown by: Figure 3 It can be seen that the variance of discrete load data shows an obvious increasing trend, which indicates that the load data after discretization has different volatility. The next step is to calculate the Pearson correlation coefficient of the typical daily load of the discrete load data and the original load data to verify that the discrete load data has a typical daily load similar to the original load data. The discrete cooling and heating load data and the original cooling and heating load data are introduced into the following formula. The calculation results are as follows: Figure 4 As shown:

[0110] .

[0111] Depend on Figure 4 It can be seen that the Pearson correlation coefficient of the typical daily load between the discrete load data and the original load data is higher than 0.93, which can verify that the discrete load data and the original load data have a high degree of similarity in typical daily loads. Therefore, it can be considered that the load data obtained by load discretization processing can control the typical daily load under the condition of changing the load volatility.

[0112] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0113] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A building load volatility analysis method based on a distributed energy system, characterized by: The method comprises determining constraint conditions, wherein the constraint conditions include determining energy balance conditions and determining equipment capacity constraints; The energy balance condition refers to the energy provided by each device in the system under the specified operation strategy can meet the user's demand for cooling, heating and electricity. The determination of the equipment capacity constraint selects the gas turbine as the power generation unit of the optimization model. The capacity of the gas turbine As the variable optimized by the algorithm, the capacity of the gas turbine determines the capacity of the waste heat boiler and the absorption chiller; The energy balance conditions are as follows: ； In the formula, , , They refer to the hourly power supply of the municipal power grid, the hourly power generation of the gas turbine, and the hourly power consumption of the electric refrigeration unit in the DES system; , They refer to the hourly cooling capacity of electric refrigeration units and absorption refrigeration units respectively; , They refer to the hourly heating capacity of waste heat boilers and gas boilers respectively; , , Respectively refer to the user's hourly electricity, cooling and heating load values. is the efficiency of the waste heat boiler; The equipment capacity constraints are as follows: ； In the formula, , , , They refer to the rated heating capacity of the gas turbine, the rated power generation of the gas turbine, the rated capacity of the waste heat boiler, and the rated capacity of the absorption refrigeration unit respectively; , They refer to the efficiency of waste heat boiler and absorption refrigeration unit respectively. The ratio of heat supplied to the gas turbine to electricity generated; The capacity of the gas boiler is determined by the capacity and heat load data of the gas turbine. The gas boiler needs to meet the maximum heating demand when the heat supply of the gas turbine is insufficient. Specifically: ； In the formula, Refers to the rated capacity of the gas boiler; Refers to the hourly heating amount of the gas turbine; The equipment capacity of the electric refrigeration unit is determined by the equipment capacity of the absorption refrigeration unit and the cooling load demand, specifically: ； In the formula, Refers to the rated capacity of the electric refrigeration unit. Refers to the hourly cooling capacity of the gas turbine.

2. The method for analyzing building load fluctuation based on distributed energy system according to claim 1 is characterized in that: The method also includes establishing a device model, wherein the establishing of the device model includes: The output thermal efficiency and electrical efficiency of the gas turbine are determined by the load rate. The calculation formula is: ； The discrete data of gas turbine operating efficiency is fitted, and the fitting function expression is: ； From the above gas turbine load factor The thermal efficiency fitting function can calculate the hourly operating efficiency of the gas turbine and the hourly gas consumption of the gas turbine: ； In the formula, , They refer to the rated power generation and the rated heating capacity of the gas turbine respectively; Refers to the calorific value of natural gas; Waste heat boiler unit model: ; In the formula, Refers to the hourly heating amount of the waste heat boiler; Gas boiler model: ; In the formula, Refers to the heating capacity of gas boiler. Refers to the amount of natural gas consumed by gas boilers hourly; Electric refrigeration unit: ; In the formula, Refers to the hourly cooling capacity of the electric refrigeration unit. Refers to the hourly power consumption of electric refrigeration units; Refers to the refrigeration COP of the electric refrigeration unit; Absorption refrigeration unit model: .

3. The method for analyzing building load fluctuation based on distributed energy system according to claim 2 is characterized in that: Including the formulation of DES operation strategy: Based on the operating efficiency of the above equipment, the operating strategies under different seasons and different load demand characteristics are discussed in detail: A: In winter and load ratio > ; < When the power supply is insufficient, the power grid will provide the power for the insufficient load. B: In winter and load ratio > ; > When the gas turbine runs at rated power, the insufficient heat and electricity loads are provided by the gas boiler and the power grid; C: In winter and load ratio < ; > When the heat load is insufficient, the gas boiler will be used to provide the insufficient heat load. D: In summer and load ratio > ; < When the power is low, the cold-power operation mode is adopted, and the insufficient power load demand is provided by the power grid; E: In summer and load ratio > ; > When the gas turbine runs at full load, the insufficient cooling load and electrical load are provided by the electric refrigeration unit and the power grid respectively; F: In summer and load ratio < When the load factor of the gas turbine is for At this time, the gas turbine can just meet all the user's electrical load and cooling load requirements for the system.

4. The method for analyzing building load fluctuation based on distributed energy system according to claim 3 is characterized in that: It also includes an evaluation index method, which comprehensively considers economic, environmental and energy efficiency factors, and compares the annual total cost and annual total cost saving rate, primary energy utilization efficiency, Emissions and The emission reduction rate is used as an evaluation indicator; Annual operating cost of the distribution system and DES annual cost savings The expression is: ； In the formula, , They refer to hourly electricity prices and natural gas unit prices respectively; , They respectively refer to the hourly electricity consumption of the distribution system and the hourly natural gas consumption of the distribution system.

5. The method for analyzing building load fluctuation based on distributed energy system according to claim 4 is characterized in that: In the above evaluation index method, primary energy efficiency The evaluation index expression is: ； In the formula, It is the hourly primary energy consumption of DES.

6. The method for analyzing building load fluctuation based on distributed energy system according to claim 5 is characterized in that: In the above evaluation index method, the annual The emission expression is: ； ； In the formula, The carbon dioxide produced per kilowatt-hour of electricity generated by a power plant; is the amount of carbon dioxide produced by the combustion of a unit volume of natural gas; , , , They respectively refer to the amount of electricity purchased by the DES system from the power grid, the amount of natural gas consumed by the DES system hourly, the amount of electricity purchased by the distribution system from the power grid, and the amount of natural gas consumed by the distribution system.

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