A thermal system regulation modeling method

Abstract

The present application belongs to the technical field of cogeneration regulation, and particularly relates to a kind of heat system regulation modeling methods: corresponding electric heating process establishes the energy flow model of electric heating energy storage and heating system;Corresponding heat storage process establishes heat storage capacity electrical model;Corresponding heat transfer process establishes heat exchanger steady-state flow model;Corresponding heat user side heat demand establishes heat energy flow model;The energy flow model of electric heating energy storage and heating system, heat storage capacity electrical model, heat exchanger steady-state flow model and heat energy flow model are matrixed based on the method of the present application, which improves the accuracy of overall system analysis, thereby improving the accuracy of electric-thermal integrated energy system regulation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cogeneration regulation, and particularly relates to a thermal system regulation modeling method. BACKGROUND

[0002] Although the development of renewable energy power generation brings clean energy to people, due to uncontrollability of wind power and photovoltaic power generation, slow growth of social electricity consumption, and problems of power grid transmission channels, etc., serious wind curtailment and light curtailment phenomena are caused. Battery energy storage is an ideal device to solve this problem, which can be regarded as an adjustment means of power supply and an adjustment means of load. If a more flexible operation mode can be realized, it has important practical significance for guaranteeing safe operation of the power grid and supporting transmission channels. Comprehensive utilization of electric heating and heat storage will realize an important part of completely clean energy supply.

[0003] At present, large-scale development of electric heating and heat storage still faces great technical challenges and cost constraints. In cold regions, coal-fired units are generally used for heating. Due to the use of "heat determines electricity", the isolation of heat demand and electricity demand causes inaccurate and delayed supply and demand response, and the regulation margin of the heating unit is very small. Winter is also the season of abundant wind power and photovoltaic power, which is an important factor causing wind curtailment and light curtailment. The wind and light power is abundant, and the output of cogeneration units is reduced, thereby reducing the heat supply. In the decision of "heat determines electricity", a high cost and energy waste situation is caused. In the past thermal power modeling, a unified representation model is not used to couple the two kinds of energy visualization. Therefore, on the basis of quantitative demand, the thermal power analysis quantitative calculation is inaccurate, causing unbalanced production and demand, and the supply and demand of electricity-heat cannot be quickly expressed through an integrated model. Therefore, there is an urgent need for a thermal modeling method consistent with the form of the electrical model to solve the above problems. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a thermal system regulation modeling method to solve the problem of inaccurate thermal power analysis quantitative calculation, causing unbalanced production and demand.

[0005] The present application is implemented as follows,

[0006] A thermal system regulation modeling method, the method comprising:

[0007] establishing an energy flow model of the electric heating and heat storage system corresponding to the electric heating process;

[0008] establishing an electrical model of the heat storage capacity corresponding to the heat storage process;

[0009] establishing a heat exchanger steady-state flow model corresponding to the heat transfer process;

[0010] A thermal energy flow model is established corresponding to the thermal demand of the user side;

[0011] The energy flow model of the electric heat storage and heat supply system, the heat storage capacity electrical model, the heat exchanger steady-state flow model, and the thermal energy flow model are matrixed as follows:

[0012]

[0013] T u,1 -T u,0 = Q u × R u

[0014]

[0015] wherein T d,o -T d,n is the thermal potential of the 1-n heat storage devices, T CHP1 -T CHPn is the thermal potential of the 1-n combined heat and power heat supply devices, R HX1 , R HX2 , R HXn are the thermal resistance of the heat exchange links, R1-R n are the thermal resistance of the user side using combined heat and power heat supply plus heat storage, Q u is the thermal resistance of the heat exchange links, R a1 -R an are the thermal resistance of the user side directly using heat storage T a , T B are the thermal potential after flowing through the user side.

[0016] Further, the heat storage capacity electrical model characterizes the heat capacity of the heat storage device in the form of a capacitor, with the thermal potential across the heat capacity as the variable, and integrates with respect to time, Q i is the heat fluid flow of the i-th heat storage device in the energy storage and release process in the non-steady state heat transfer stage, C i is the heat capacity of the heat storage device, is the rate of change of the thermal potential of the heat fluid flowing into the heat storage device.

[0017] Further, the heat exchanger steady-state flow model includes: taking the heat exchanger as a thermal resistance, the thermal energy difference as the driving potential, and the heat fluid as the heat flow, to obtain the heat exchanger steady-state flow model:

[0018] ΔU = QR e

[0019] ΔU = T h,j -T c,i

[0020] R e = R(KA,m hm c )

[0021] ΔU is driving potential, exothermic is positive, endothermic is negative; Q is heat flow; R e =R(KA,m h ,m c ) is thermal resistance;

[0022] In the heat network, the heat fluid passes through the parallel, series and multi-loop three forms of the heat flow network, and the heat driving potential is formed by the potential difference at both ends to convert heat flow.

[0023] Further, the energy flow model of the electric heating energy storage and heating system is:

[0024]

[0025] Wherein, T d,0 is the heat potential generated by the electric heating at the energy storage heat exchange node, T u,i is the heat potential stored by the electric heating energy storage device, and T a is the heat potential energy supplied by the heat storage device.

[0026] Further, the heat energy flow model of the heat user side is:

[0027]

[0028] Wherein, T i is the heat potential of the i-th heat user, R i is the thermal resistance of the i-th user, and T i-1 is the heat potential of the i-1-th user.

[0029] Compared with the prior art, the present application has the beneficial effects that:

[0030] Based on the method of the present application, the accuracy of overall system analysis is improved, so as to improve the accuracy of electric-heat comprehensive energy system regulation. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is an electrification structure schematic diagram of the heat exchanger power flow model of the present application;

[0032] Figure 2 It is a heat exchanger power flow model converted from a physical model in a parallel heat exchanger network of the present application;

[0033] Figure 3 Energy flow model of the electric heating energy storage and heating system;

[0034] Figure 4 Electrification characterization and matrix of the electric heating-energy storage-heating system. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0036] The present application proposes a thermal system regulation modeling method. The thermal resistance and thermal capacity model of the heating, heat transfer, heat leakage and heat storage characteristics is used to characterize the electric heating, heat storage and heat release, and the electrical modeling of the thermal system is realized. The model established based on the method of the present application improves the accuracy of the overall system analysis, thereby improving the accuracy of the regulation.

[0037] In order to achieve the above-mentioned purpose of the present application, the present application describes a thermal system regulation modeling method by the following embodiment. The thermal resistance and thermal capacity model of the heating, heat transfer, heat leakage and heat storage characteristics is used to characterize the electrical modeling. The method comprises:

[0038] The four processes of electric heating, heat storage and heat release (heat transfer) in the thermal system and the user side heat demand are respectively established as electrical models; and the entire process is uniformly modeled; wherein:

[0039] The energy flow model of the electric heating and heat supply system corresponding to the electric heating process is established;

[0040] The electrical model of the heat storage capacity corresponding to the heat storage process is established;

[0041] The steady-state flow model of the heat exchanger corresponding to the heat transfer process is established;

[0042] The thermal energy flow model corresponding to the heat demand of the user side is established;

[0043] The thermal resistance and thermal capacity model of the heating, heat transfer, heat leakage and heat storage characteristics in the form of electrical modeling: in the electric heating, heat storage and heat release, the energy change of heat in the non-steady state transfer stage, the heat transfer resistance between the hot fluid, cold fluid and heat transfer wall in the heat exchanger and heat storage equipment, and the heat leakage resistance of the heat storage equipment in the heat storage device are characterized by the heat resistance R, which is used to express the size of each heat loss, and the calculation accuracy of the entire system is improved to the maximum extent.

[0044] The electrical model of the heat storage capacity, the heat capacity of the heat storage equipment is expressed by the capacitance, and the thermal potential at both ends of the heat capacity is used as the variable, and the integral is performed with respect to time, Q i The hot fluid flow of the i-th heat storage equipment in the energy storage and release process of heat in the non-steady state transfer stage, i The heat capacity of the heat storage equipment, The rate of change of the thermal potential of the hot fluid flowing into the heat storage equipment.

[0045] Reference Figure 1As shown, the heat exchanger power flow model is based on the steady-state performance of the heat exchanger, and analyzes the flow of hot fluid to establish an electrical form of steady-state model; the heat leakage is the thermal resistance of the heat exchanger, and the thermal energy difference is the driving potential, and the hot fluid establishes a heat flow model:

[0046]

[0047] According to the above thermodynamic model, the heat exchanger power flow model is characterized by electricity:

[0048] ΔU = QR e

[0049] ΔU = T h,j -T c,i

[0050] R e = R(KA,m h ,m c )

[0051] ΔU is the driving potential, and the heat release is positive and the heat absorption is negative. Q is the heat flow (hot fluid flow); R e is the thermal resistance, which depends on (KA,m h ,m c ), where KA is the heat exchanger area, m h heat transfer coefficient, and m c the mass flow of two fluid flows. Based on the thermoelectric analogy analysis, the heat exchanger power flow model is established, which is unified with the power system power flow model.

[0052] Referring to Figure 2 As shown, the steady-state power flow model of the heat exchange system can be analogized to an electrical model with three basic structures, namely parallel, series and multi-loop, and the three forms of heat flow in the heat network are formed by the heat driving potential of the two end heat potential difference. For example, a three-way parallel heat exchanger network is converted from a physical model to an electrical power flow model, which is represented as:

[0053]

[0054] Where Q CO is the heat flow out of the end of the heat exchange network after heat exchange in the parallel heat exchanger, T h1 , T h2 , T h3 represent the heat potential at the inlet of the first, second and third heat exchangers, respectively, and T ci represents the heat potential of the hot fluid in the heat network before entering the heat exchange network. The construction method of the power flow model of the series and multi-loop heat exchange network is consistent with that of the parallel heat exchange network.

[0055] Electricity heating and heat storage capacity model:

[0056] S i (j+1)=S i (j)+P hs_i (j)Δt-η×S i (j)

[0057] Where: S i (j+1), S i (j) are the cumulative heat storage capacity MWh of the heat storage system in the j+1 and j scheduling stages of the i-th electric heating equipment, P hs_i (j) is the output power of the heat storage system in stage j; Δt is the scheduling period of the heat storage system, h; η is the heat storage efficiency of the heat storage system within Δt (the heat storage system will have heat leakage loss within Δt), which is converted into electrical form:

[0058] See also Figure 3 As shown in the figure, the energy flow model of the electric heating energy storage and heating system is:

[0059]

[0060] Where T d,0 is the thermal potential generated by electric heating at the energy storage heat exchange node, T u,i is the heat potential stored in the electric heating energy storage device, T a Thermal potential energy used to heat the thermal storage device.

[0061] The thermal energy flow model represented by the thermal user side is:

[0062]

[0063] Among them, T i is the thermal potential of the ith hot user, R i is the thermal resistance of the i-th user, T i-1 is the thermal potential of the i-1th user. The building thermal energy flow model on the heat user side consists of N users, so it can be constructed as a series heat network model.

[0064] See also Figure 4 As shown, the matrix of the electric heating-heat storage-heating system is:

[0065]

[0066] T u,1 -T u,0 =Q u ×R u

[0067]

[0068] It consists of three parts: heat storage, heat transfer and heat leakage in the heat storage-heating system, among which Td,o -T d,n is the thermal potential of 1-n heat storage devices, T CHP1 -T CHPn is the thermal potential of 1-n combined heat and power heating devices, R HX1 , R HX2 , R HXn , R1-R n is the user-side thermal resistance using combined heat and power heating plus heat storage, Q u is the heat transfer link heat leakage thermal resistance, R a1 -R an is the user-side thermal resistance directly using heat storage, T a , T B is the thermal potential after flowing through the user side.

[0069] The heat of the heat storage device passes through the heat network, together with the heat generated by the electric heating device, through the heat transfer link, to the user side, and the leakage heat occurring in the heat transfer process, and the heat network of each leakage heat is modeled as a leakage heat resistance. The electric heating-heat storage-heating system is calculated in an electrified form.

[0070] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A thermal system control modeling method, characterized in that: The method includes: Establish an energy flow model of the electric heating energy storage and heating system corresponding to the electric heating process; Establish an electrical model of heat storage capacity corresponding to the heat storage process; Establish a steady-state flow model of the heat exchanger corresponding to the heat transfer process; Establish a thermal energy flow model corresponding to the thermal demand on the thermal user side; The energy flow model of the electric heating energy storage and heating system, the electrical model of the heat storage capacity, the steady-state power flow model of the heat exchanger, and the thermal energy flow model are expressed in matrices as follows: T u,1 -T u,0 =Q u ×R u Where T d,o ......T d,n is the thermal potential of n+1 heat storage devices, T CHP1 ......T CHPn is the thermal potential of n cogeneration heating equipment, R HX1 、R HX2 ...R HXn are the heat leakage resistance of the heat exchange link, R1...R n Q is the thermal resistance on the user side of combined heat and power heating and heat storage, u is the heat leakage heat flow in the heat transfer link, R a1 ......R an is the thermal resistance on the user side that directly uses the heat storage, T a 、T B It is the thermal potential after flowing through the user side.

2. The method according to claim 1, characterized in that The heat storage capacity electrical model represents the heat capacity of the heat storage device in the form of capacitance, takes the thermal potential at both ends of the heat capacity as a variable, and integrates it over time. Q i is the thermal fluid flow rate of the i-th heat storage device during the storage and release process of heat in the non-steady-state transfer stage, C i is the heat capacity of the heat storage device, is the rate of change of thermal potential of the thermal fluid flowing into the heat storage device.

3. The method according to claim 1, characterized in that The steady-state flow model of the heat exchanger includes: taking the heat exchanger as the thermal resistance, the thermal energy difference as the driving potential, and the thermal fluid as the heat flow, to obtain the steady-state flow model of the heat exchanger: ΔU=QR e ΔU=T h,j -T c,i R e =R(KA,m h m c ) ΔU is the driving potential, exothermic is positive and endothermic is negative; Q is the heat flow; R e =R(KA,m h ,m c ) is the thermal resistance; In the thermal network, the thermal fluid passes through the parallel, series and multi-loop forms of the heat flow network, and the thermal potential difference at both ends forms a thermal driving potential for heat flow conversion.

4. The method according to claim 1, characterized in that The energy flow model of the electric heating energy storage and heating system is: Among them, T d,0 is the thermal potential generated by electric heating at the energy storage heat exchange node, T u,i is the heat potential stored in the electric heating energy storage device, T a Thermal potential energy used to heat the thermal storage device.

5. The method according to claim 1, characterized in that The thermal energy flow model on the heat user side is: Among them, T i is the thermal potential of the ith hot user, R i is the thermal resistance of the i-th user, T i-1 is the heat potential of the i-1th user.

Images