A method for calculating the marginal contribution of diversified market players

Abstract

The present invention proposes a method for calculating the marginal contribution of diversified market entities. First, according to the operation principle of central air conditioning, based on the law of conservation of energy, thermodynamics and mass conservation, a physical model of central air conditioning in public buildings is established, and a flexible control strategy for central air conditioning is proposed; considering that air conditioning users participate in the energy and reserve market under the unified coordination of aggregators, a two-layer market optimization model of aggregators containing multiple types of public buildings is constructed. The upper layer is the aggregator market optimization model, and the lower layer is the electricity market clearing model. Based on the KKT condition and duality theory, the two-layer optimization problem is converted into a single-layer optimization model with equilibrium constraints to achieve efficient solution of the model. The present invention can solve the market optimization results of air conditioning load aggregators in the energy and reserve market for a continuous period of time, evaluate the marginal contribution of each market entity, and thus provide support for the market power supervision of load aggregators in the electricity market environment.

Description

Technical Field

[0001] The present invention belongs to the field of power system calculation, and in particular relates to a method for calculating the marginal contribution of diversified market entities. Background Art

[0002] In recent years, with the development of social economy and the improvement of people's living standards, people's dependence on public buildings has continued to increase. Building loads have gradually become the main part of summer cutting-edge loads, among which air conditioning loads are particularly prominent. The central air-conditioning loads of public buildings are widely distributed, account for a large proportion and are highly controllable. They are high-quality demand-side resources with huge regulation potential. By integrating, managing and controlling air-conditioning load resources, the demand for power system expansion can be reduced, and the reliability, flexibility and stability of the power system can be improved. Buildings have different functions, many types of central air conditioners, different performances, response speeds and capacities. If each building participates in the bidding separately, it will inevitably bring about problems such as complicated management and control, difficult scheduling and slow response. Against this background, load aggregators came into being. Aggregators form a scheduling mode with high reliability and fast response speed by unified management and centralized control of air-conditioning loads.

[0003] In an open power market on both the supply and demand sides, flexible resources on the demand side can participate in the energy market and ancillary service market with the intervention of aggregators, transforming from passive peak avoidance to active participation. However, current power regulation focuses on monitoring and suppressing the market power of generators, while there is still a lack of appropriate regulatory mechanisms for analyzing the market power of large users / load aggregators.

[0004] The present invention proposes a bidding strategy for air conditioning load aggregators under the power market supervision environment. First, according to the operation principle of central air conditioning, based on the law of conservation of energy, thermodynamics and mass conservation, a physical model of central air conditioning in public buildings is established, and a flexible control strategy for central air conditioning is proposed. Secondly, considering that air conditioning users participate in the energy and reserve markets under the unified coordination of aggregators, a two-layer bidding model of aggregators containing multiple types of public buildings is constructed, in which the upper layer is the aggregator bidding model and the lower layer is the power market clearing model. Based on the KKT condition and duality theory, the two-layer optimization problem is transformed into a single-layer optimization model with equilibrium constraints to achieve efficient solution of the model. Summary of the invention

[0005] Purpose of the invention: The present invention provides a method for calculating the marginal contribution of diversified market entities. First, a physical model of central air conditioning in public buildings is established, and a flexible control strategy for central air conditioning is proposed. Secondly, considering that air-conditioning users participate in the energy and backup markets under the unified coordination of aggregators, a two-layer market optimization model of aggregators containing multiple types of public buildings is constructed, in which the upper layer is the aggregator market optimization model and the lower layer is the electricity market clearing model. Based on the KKT condition and duality theory, the two-layer optimization problem is transformed into a single-layer optimization model with equilibrium constraints to achieve efficient solution of the model.

[0006] Technical solution: The present invention provides a method for calculating the marginal contribution of diversified market entities, comprising the following steps:

[0007] Step 1: According to the operation principle of central air conditioning, based on the law of conservation of energy, thermodynamics and mass conservation, a physical model of central air conditioning in public buildings is established.

[0008] Step 2: Establish an optimization model for the upper-level aggregator market; establish a lower-level electricity market clearing model

[0009] Step 3: Through the KKT condition and strong duality theory, the lower-level electricity market clearing model is transformed into a single-layer mathematical optimization model with equilibrium constraints (MPEC). The GAMS software BARON solver is used to solve the above MPEC problem and obtain the market optimization results and the marginal contribution of multiple market players.

[0010] Further, the step 1 comprises the following steps:

[0011] Step 101: The central air-conditioning system of a public building is mainly composed of three circulation systems of chilled water, cooling water and refrigerant, including one or more refrigeration units and a corresponding number of chilled water pumps, cooling water pumps and cooling towers, as well as terminal equipment such as chillers, fan coils or fresh air units. For an air-conditioning system with N1 chillers, N2 chilled water pumps, N3 cooling coil fans, N4 cooling water pumps and N5 cooling towers, its energy consumption model can be expressed as follows:

[0012]

[0013] Where: P HVAC is the total energy consumption of the central air conditioning system, P chiller,i is the energy consumption of the i-th chiller, P CHWpump,j is the energy consumption of the jth chilled water pump, P coil,k is the energy consumption of the kth cooling coil fan, P CWpump,m is the power of the mth cooling water pump, P tower,nis the power of the nth cooling tower.

[0014] 1) Chiller:

[0015] For a multi-chilled water unit air conditioning system, the energy consumption of the chiller depends on the coefficient of performance (COP), and its model can be expressed as:

[0016]

[0017] Where: P chiller is the energy consumption of the chiller, Q e is the cooling load on the chilled water circulation side. Among them, COP is related to the evaporation temperature, condensation temperature and load rate of the chiller, which can be expressed as:

[0018]

[0019] Where: r is the chiller load rate, Q is the cooling load e With rated load Q nom The ratio of r = Q e / Q nom a1 and a2 are irreversible loss coefficients, and their values ​​are determined by the chiller test data. e is the evaporation temperature, T c is the condensation temperature, which can be calculated using the following formula:

[0020]

[0021]

[0022] Where: T chwr and T cws They represent the chilled water return temperature and the condensed water supply temperature, respectively. c Indicates the load on the condensate circulation side, F chw (m chw ) and F cw (m cw ) is the chilled water flow m chw and cooling water flow m cw The empirical formula of .

[0023] 2) Frequency conversion water pump:

[0024] The water pumps in the central air conditioning system mainly include chilled water pumps and cooling water pumps, which provide power for the water system circulation. At present, the water pumps in most building air conditioning systems operate at rated power, and the operating efficiency is low. This article assumes that all water pumps are equipped with variable frequency control systems to facilitate flow control and reduce energy consumption. The power of the variable frequency water pump depends on the water flow, that is:

[0025]

[0026]

[0027]

[0028] Where: P chw.pump is the chilled water pump power, P cw.pump is the cooling water pump power, m chw is the chilled water flow rate, m cw is the cooling water flow rate. m chw.nom is the rated value of chilled water flow, m cw.nom is the cooling water flow rating, k p and A p is the correlation coefficient, X w is the pump water flow ratio, η var is the mechanical efficiency of the pump, which is related to the water flow rate.

[0029] 3) Fan coil unit:

[0030] The fan coil is the terminal device in the central air conditioning system. The chilled water in the coil exchanges heat with the indoor air to achieve the purpose of cooling. The heat exchange process is expressed as:

[0031]

[0032] Where: Q room.k is the corresponding regional cooling load, m sa,k and m chw,k are the fan air flow and the chilled water flow in the coil respectively; c c,1,k , c c,1,k , c c,1,k is the kth fan constant; T chws is the chilled water supply temperature, T ma,k is the mixed temperature of indoor and outdoor air in the bellows, Calculated, where T out is the outdoor temperature, is the indoor temperature of the room corresponding to the kth fan, and the sum of the chilled water flow in the coil is equal to the total chilled water flow in the system, that is:

[0033]

[0034] Where: m chw,j is the chilled water flow rate in the jth chilled water pump, m chw,k is the chilled water flow rate in the kth fan coil unit.

[0035] 4) Cooling tower:

[0036] The cooling tower is a heat dissipation device of the central air conditioning system. It absorbs the heat in the indoor air and discharges it into the atmosphere through the circulation of cooling water. The heat dissipation process is expressed as:

[0037]

[0038] Where: m ta,n and m cw,n are the wind speed and cooling water flow rate in the cooling tower respectively; T cwr and T wb are the chilled water return temperature and the cooling tower wet bulb temperature, respectively. c,i is the cooling water circulation load of the i-th chiller, c c,1,n ,c c,2,n ,c c,3,n is the constant of the nth cooling tower. In addition, the total flow of cooling water in the air-conditioning system remains unchanged, that is:

[0039]

[0040] The energy consumption of fan coil units and cooling towers comes from fans. Their energy consumption model is the same as that of variable frequency water pumps, which can be expressed as:

[0041]

[0042]

[0043]

[0044] Where: P coil is the fan coil energy consumption, P tower is the energy consumption of cooling tower, m sa is the fan coil air flow rate, m ta is the cooling tower air flow rate. m sa.nom is the rated value of the fan coil air flow, m ta.nom Rated value of cooling tower air flow, k f and A f is the correlation coefficient, X a is the fan air flow ratio, η var is the mechanical efficiency of the fan, which is related to the wind flow rate;

[0045] Step 102: Establish the constraints of the central air conditioning system, mainly including the interaction between devices and the physical constraints of variables.

[0046] The interaction between the chiller and the refrigeration / cooling cycle can be expressed as:

[0047]

[0048]

[0049] In the formula, the cooling water eliminates the heat on the cooling water side based on the energy balance principle, including the heat generated by the compressor and the heat transferred to the condenser via the evaporator on the chilled water circulation side. Therefore, the cooling load Q in the cooling water circulation is c,i =Q e,i +P chiller,i .Q e,i is the cooling load in the chilled water cycle of the i-th chiller, P chiller,i is the energy consumption of the i-th chiller, m chw.m is the chilled water flow rate in the jth chilled water pump, m cw.m is the cooling water flow rate in the mth cooling water pump. w is the specific heat capacity of water, T chwr and T chws Respectively represent the chilled water return temperature and supply water temperature, T cwr and T cws Represent the cooling water return temperature and supply water temperature respectively.

[0050] To ensure the performance of the air conditioning system, each control variable must be maintained within an acceptable range:

[0051] T chws.min ≤T chws ≤T chws.max

[0052] T cws.min ≤T cws ≤T cws.max

[0053] m chw,j.min ≤m chw,j ≤m chw,j.max

[0054] m cw,m.min ≤m cw,m ≤m cw,m.max

[0055] m sa,k.min ≤m sa,k ≤m sa,k.max

[0056] m ta,n.min ≤m ta,n ≤m ta,n.max .

[0057] Where: T chws is the chilled water supply temperature, T chws.max , T chws.min It is the upper and lower limits of the chilled water supply temperature. cws is the cooling water supply temperature, T cws.max , T cws.min It is the upper and lower limits of cooling water supply temperature. m chw,jis the water flow rate of the jth chilled water pump, m chw,j.max 、m chw,j.min It is the upper and lower limits of the chilled water pump flow rate. m cw,m is the water flow rate of the mth cooling water pump, m cw,m.max 、m cw,m.min It is the upper and lower limits of the cooling water pump flow rate. m sa,k is the air flow rate of the kth coil fan, m sa,k.max 、m sa,k.min The upper and lower limits of the coil fan air flow rate. m ta,n is the wind flow rate of the nth cooling tower, m ta,n.max 、m ta,n.min It is the upper and lower limits of the cooling tower air flow.

[0058] Further, the step 2 comprises the following steps:

[0059] Step 201: Establish an upper-level air conditioning load aggregator market optimization model.

[0060] 1) Objective function:

[0061] The load aggregator aggregates a certain number of public buildings and has partial control over the central air conditioning of the public buildings within the aggregation range. The objective function of the upper optimization model is to maximize the aggregator's profit:

[0062]

[0063] The objective function consists of three parts: the profit obtained by aggregator j from participating in the energy market Profits from alternate markets and the cost U required to change the electricity consumption behavior of air conditioner users j,i,t , the specific expression is as follows:

[0064]

[0065]

[0066]

[0067] Where: and are the market optimization results of aggregator j in the energy and reserve markets respectively; and represents the capacity of the aggregator in the energy and reserve market. This paper adopts the utility function U of indoor temperature j,i,t represents the loss compensation caused by the change of comfort level, where and denote the indoor temperature and reference temperature of area k in building i under the jurisdiction of aggregator j, respectively. Represents the quantitative economic cost correlation coefficient.

[0068] 2) Constraints:

[0069] Aggregators use the load curve of the response period corresponding to the normal production working days in the most recent week as the baseline, and use the reduced power as non-productive power generation resources to participate in the energy and reserve market bidding. and marginal cost The following constraints must be met:

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077] Where: t' represents the previous period of the current period, that is, t' = t + 1, is the baseline load of aggregator j, Minimum energy consumption for air conditioning; and They are the upper and lower limits of the assessed energy and reserve market bidding capacity for each building; and are the upper and lower bounds of marginal costs in the energy and reserve markets respectively.

[0078] At the same time, to ensure the balance of the energy and reserve markets, the minimum bidding capacity of the aggregator should meet the following constraints.

[0079]

[0080]

[0081] Where: Energy market capacity for all buildings, Spare market capacity provided for all buildings.

[0082] Secondly, the room temperature time-varying equation is derived:

[0083]

[0084] In the formula: In the formula: α i(t) is the thermal parameter related to the building at the i-th building in period t, β i is the building thermal parameters related to walls and windows of the i-th building, γ i is the building thermal parameter related to the indoor temperature of the i-th building, ignoring the heat loss in the air conditioning system, Q j,i,k represents the cooling capacity output by the central air-conditioning system in area k of building i, is the indoor temperature.

[0085] Establish summer human comfort constraints to control the indoor temperature of public buildings within a certain range:

[0086]

[0087] Where: and The upper and lower limits of room temperature.

[0088] Step 202: Establish a lower-level electricity market clearing model.

[0089] The electricity market clearing model refers to the PJM market in the United States, taking into account the joint clearing of the energy market and the reserve market, and settles according to the actual market optimization results. The objective function is to minimize the purchase cost of energy and reserve services.

[0090]

[0091] Where T and J represent the total number of scheduling periods and the total number of buildings, respectively.

[0092] Among them, the winning capacity and The following constraints must be met:

[0093]

[0094]

[0095]

[0096]

[0097] Where: Bidding capacity for the aggregator energy market and reserve market, Energy market capacity for all buildings, Spare market capacity provided for all buildings. are the dual variables of each equation.

[0098] Further, the step 3 is:

[0099] Considering that the lower-level model established above is a linear model, the KKT condition is used to transform the objective function of the lower-level optimization model into the corresponding constraint conditions:

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108] To facilitate the solution, the complementary relaxation condition is linearized using strong duality theory to obtain the following formula:

[0109]

[0110] The BARON solver of GAMS software is used to solve the above MPEC problem, and the aggregator's profit and market optimization results as well as the marginal contribution of diversified market players are obtained.

[0111] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0112] 1. In the present invention, load aggregators aggregate a certain number of public buildings to achieve unified management and regulation of air conditioning resources, which can form reliable demand-side resources to participate in the energy and reserve markets, assist in grid regulation, and obtain considerable economic profits. The joint clearing mechanism of the energy and reserve markets can make more full use of demand-side resources, which is conducive to increasing the aggregators' own profits.

[0113] 2. According to the operation principle of central air conditioners, the law of conservation of energy, the principle of thermodynamics, and the principle of conservation of mass, the present invention establishes a physical model of central air conditioners in public buildings and proposes a flexible control strategy for central air conditioners. The flexible control strategy for central air conditioners can accurately track the load, improve the operating efficiency of central air conditioners, reduce equipment start-up and shutdown, and extend the life of air conditioners. BRIEF DESCRIPTION OF THE DRAWINGS

[0114] Figure 1 A flow chart of the method is provided for the present invention;

[0115] Figure 2 is the outdoor temperature;

[0116] Figure 3 is the indoor temperature of public buildings under the jurisdiction of aggregator A. DETAILED DESCRIPTION

[0117] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0118] The present invention is described below by taking an air conditioning load aggregator A as an example:

[0119] There are 8 buildings in the aggregation range. The reference temperature, number of floors and unit information of each building are shown in Table 1. The outdoor temperature is Figure 2 shown.

[0120] The revenue of aggregator A under the two mechanisms of independent sequential clearing and joint clearing are shown in Table 2. Under the independent sequential clearing mechanism, since aggregator A reserves capacity to participate in the reserve market, the revenue of the energy market decreases. Because other aggregators also put their remaining capacity into the reserve market for bidding, the competitiveness of aggregator A in the subsequent reserve market decreases. Under the joint clearing mechanism, the revenue of aggregator A can be increased by about 3.33%. It can be seen that compared with the independent sequential clearing mechanism, the joint clearing mechanism of the energy and reserve market can achieve the coordinated optimization of energy and reserve, which is conducive to the aggregator to improve its own revenue.

[0121] Aggregators control indoor temperature and air conditioning system energy consumption by changing the cooling water temperature, chilled water temperature, flow rate, and wind speed of the air conditioning system. Taking the central air conditioning system of Hotel 2 as an example, the control strategy from 11:00 to 12:00 is shown in Table 3. The indoor temperature of each building is as follows: Figure 3 The central air conditioning system mainly adopts the control strategy of "large temperature difference-small flow". Under this strategy, the flow and wind speed both track the trend of cooling capacity, which is conducive to reducing the energy consumption of the water pump. The energy efficiency ratio of the central air conditioning system is close to 5.0, which is significantly higher than the energy efficiency ratio of most current central air conditioners, and the operating effect is significantly improved. Figure 3 It can be seen that compared with the current start-stop control and periodic rotation control strategies, the flexible control method proposed in this paper can reduce indoor temperature fluctuations and reduce users' thermal discomfort.

[0122] The above simulation results verify the effectiveness and practicality of the method of the present invention. The method of the present invention fully utilizes demand-side resources, which is beneficial for aggregators to increase their own profits. At the same time, the flexible control strategy of central air conditioners can accurately track the load, improve the operating efficiency of central air conditioners, reduce equipment start-up and shutdown, and extend the life of air conditioners.

[0123] Table 1 Building and central air conditioning equipment parameters

[0124]

[0125] Table 2: Aggregator revenue under sequential independent clearing and joint clearing mechanisms

[0126]

[0127]

[0128] Table 3 Central air conditioning control strategy of Hotel 2

[0129]

Claims

1. A method for calculating the marginal contribution of diversified market entities, characterized in that: The method comprises the following steps: Step 1: According to the operation principle of central air conditioning, based on the law of conservation of energy, thermodynamics and mass conservation, establish a physical model of central air conditioning in public buildings; Step 2: Establish an upper-level aggregator market optimization model and a lower-level power market clearing model; Step 3: The lower-level electricity market clearing model is transformed into a single-layer mathematical optimization model with balance constraints through KKT conditions and strong duality theory. The GAMS software BARON solver is used to solve the above single-layer mathematical optimization model with balance constraints, so as to obtain the market optimization results and the marginal contribution of multiple market players; The step 1 comprises the following steps: Step 101: The central air-conditioning system of a public building includes three circulation systems of chilled water, cooling water and refrigerant, including one or more refrigeration units and corresponding numbers of chilled water pumps, cooling water pumps and cooling towers, as well as chillers, fan coils or fresh air units. For an air-conditioning system with N1 chillers, N2 chilled water pumps, N3 cooling coil fans, N4 cooling water pumps and N5 cooling towers, its energy consumption model is expressed as follows: Where: P HVAC is the total energy consumption of the central air conditioning system, P chiller,i is the energy consumption of the i-th chiller, P CHWpump,j is the energy consumption of the jth chilled water pump, P coil,k is the energy consumption of the kth cooling coil fan, P CWpump,m is the power of the mth cooling water pump, P tower,n is the power of the nth cooling tower; 1) Chiller: For a multi-chilled water unit air conditioning system, the energy consumption of the chiller depends on the energy efficiency ratio COP, and its model is expressed as: Where: P chiller is the energy consumption of the chiller, Q e is the cooling load on the chilled water cycle side, where COP is related to the evaporation temperature, condensation temperature and load rate of the chiller, and is expressed as: Where r is the chiller load factor, Q is the cooling load on the chilled water cycle side e With rated load Q nom The ratio of r = Q e / Q nom , a1, a2 are irreversible loss coefficients, the values ​​are determined by the chiller test data, T e is the evaporation temperature, T c is the condensation temperature, T e and T c Calculated using the following formula: Where, T chwr and T cws They represent the chilled water return temperature and the condensed water supply temperature, respectively. c Indicates the load on the condensate circulation side, F chw (m chw ) and F cw (m cw ) is the chilled water flow m chw and cooling water flow m cw The function value of 2) Frequency conversion water pump: The water pumps in the central air-conditioning system include chilled water pumps and cooling water pumps, which provide power for the water system circulation; the water pumps in the building air-conditioning system are all operated at rated power. Assuming that all water pumps are equipped with a variable frequency control system to control the flow, the power of the variable frequency water pump depends on the water flow, that is: Where: P chw.pump is the chilled water pump power, P cw.pump is the cooling water pump power, m chw is the chilled water flow rate, m cw is the cooling water flow rate, m chw.nom is the rated value of chilled water flow, m cw.nom is the cooling water flow rating, k p and A p is the correlation coefficient, X w is the pump water flow ratio, η var is the mechanical efficiency of the water pump, which is related to the water flow rate, and b0, b1, b2, and b3 are correlation coefficients; 3) Fan coil unit: The fan coil is the terminal device in the central air conditioning system. The chilled water in the coil exchanges heat with the indoor air to achieve the purpose of cooling. The heat exchange process is expressed as: Where: Q room.k is the corresponding regional cooling load, m sa,k and m chw,k are the fan air flow and the chilled water flow in the coil respectively; c c,1,k , c c,1,k , c c,1,k is the kth fan constant; T chws is the chilled water supply temperature, T ma,k is the mixed temperature of indoor and outdoor air in the bellows, Calculated, where T out is the outdoor temperature, is the indoor temperature of the room corresponding to the kth fan, and the sum of the chilled water flow in the coil is equal to the total chilled water flow in the system, that is: Where: m chw,j is the chilled water flow rate in the jth chilled water pump, m chw,k is the chilled water flow rate in the kth fan coil; 4) Cooling tower: The cooling tower is a heat dissipation device of the central air conditioning system. It absorbs the heat in the indoor air and discharges it into the atmosphere through the circulation of cooling water. The heat dissipation process is expressed as: Where: m ta,n and m cw,n are the wind speed and cooling water flow rate in the cooling tower respectively; T cwr and T wb are the chilled water return temperature and the cooling tower wet bulb temperature, respectively. c,i is the cooling water circulation load of the i-th chiller, c c,1,n ,c c,2,n ,c c,3,n is the constant of the nth cooling tower. In addition, the total flow of cooling water in the air-conditioning system remains unchanged, that is: The energy consumption of fan coil units and cooling towers comes from fans. Their energy consumption model is the same as that of variable frequency water pumps, which can be expressed as: Where: P coil is the fan coil energy consumption, P tower is the energy consumption of cooling tower, m sa / ta Represented as m sa and m ta , where m sa is the fan coil air flow rate, m ta is the cooling tower air flow, m sa / ta.nom Represented as m sa.nom and m ta.nom , where m sa.nom is the rated value of the fan coil air flow, m ta.nom Rated value of cooling tower air flow, k f and A f is the correlation coefficient, X a is the fan air flow ratio, η var is the mechanical efficiency of the fan, which is related to the fan air flow ratio, and c0, c1, c2, and c3 are correlation coefficients; Step 102: Establishing constraints of the central air conditioning system, including interactions between devices and physical constraints of variables; The interaction between the chiller and the refrigeration / cooling cycle can be expressed as: In the formula, the cooling water eliminates the heat on the cooling water side based on the energy balance principle, including the heat generated by the compressor and the heat transferred to the condenser via the evaporator on the chilled water circulation side. The cooling load Q in the cooling water circulation is c,i =Q e,i +P chiller,i , Q e,i is the cooling load in the chilled water cycle of the i-th chiller, P chiller,i is the energy consumption of the i-th chiller, m chw.j is the chilled water flow rate in the jth chilled water pump, m cw.m is the cooling water flow rate in the mth cooling water pump, c w is the specific heat capacity of water, T chwr and T chws Respectively represent the chilled water return temperature and supply water temperature, T cwr and T cws Respectively represent the cooling water return temperature and supply water temperature; To ensure the performance of the air conditioning system, each control variable must be maintained within an acceptable range: T chws.min ≤T chws ≤T chws.max T cws.min ≤T cws ≤T cws.max m chw,j.min ≤m chw,j ≤m chw,j.max m cw,m.min ≤m cw,m ≤m cw,m.max m sa,k.min ≤m sa,k ≤m sa,k.max m ta,n.min ≤m ta,n ≤m ta,n.max Where, T chws is the chilled water supply temperature, T chws.max 、T chws.min is the upper and lower limits of the chilled water supply temperature, T cws is the cooling water supply temperature, T cws.max 、T cws.min is the upper and lower limits of cooling water supply temperature, m chw,j is the water flow rate of the jth chilled water pump, m chw,j.max 、m chw,j.min is the upper and lower limits of the chilled water pump flow rate, m cw,m is the water flow rate of the mth cooling water pump, m cw,m.max 、m cw,m.min is the upper and lower limits of the cooling water pump flow rate, m sa,k is the air flow rate of the kth coil fan, m sa,k.max 、m sa,k.min is the upper and lower limits of the coil fan air flow, m ta,n is the wind flow rate of the nth cooling tower, m ta,n.max 、m ta,n.min It is the upper and lower limits of the cooling tower air flow.

2. The method for calculating the marginal contribution of diversified market entities according to claim 1 is characterized by: The step 2 comprises the following steps: Step 201: Establishing the upper air conditioning load aggregator market optimization model 1) Objective function: The load aggregator aggregates a certain number of public buildings and has partial control over the central air-conditioning of the public buildings within the aggregation range. The objective function of the upper optimization model is to maximize the aggregator's profit: The objective function consists of three parts: the profit obtained by aggregator j from participating in the energy market Profits from alternate markets and the cost U required to change the electricity consumption behavior of air conditioner users j,i,t , the specific expression is as follows: Where: and are the market optimization results of aggregator j in the energy and reserve markets respectively; and represents the aggregator's winning bid capacity in the energy and reserve market, using the utility function U of indoor temperature j,i,t represents the loss compensation caused by the change of comfort level, where and denote the indoor temperature and reference temperature of area k in building i under the jurisdiction of aggregator j, respectively. represents the correlation coefficient of quantitative economic cost; 2) Constraints: Aggregators use the load curve of the response period corresponding to the normal production working day in the most recent week as the baseline, and use the reduced electricity as non-productive power generation resources to participate in the energy and reserve market bidding, bidding for capacity and marginal cost The following constraints must be met: In the formula, t' represents the previous period of the current period, that is, t'=t+1, is the baseline load of aggregator j, Minimum energy consumption for air conditioning; and They are the upper and lower limits of the assessed energy and reserve market bidding capacity for each building; and are the upper and lower bounds of marginal costs in energy and reserve markets, respectively; To ensure a balanced energy and reserve market, the minimum bidding capacity of the aggregator should meet the following constraints: Where: Energy market capacity for all buildings, spare market capacity for all buildings; The room temperature time-varying equation is derived: Where: α i (t) is the thermal parameter related to the building at the i-th building in period t, β i is the building thermal parameters related to walls and windows of the i-th building, γ i is the building thermal parameter related to the indoor temperature of the i-th building, ignoring the heat loss in the air conditioning system, Q j,i,k represents the cooling capacity output by the central air-conditioning system in area k of building i, is the indoor temperature; Establish summer human comfort constraints to control the indoor temperature of public buildings within a certain range: Where: and are the upper and lower limits of room temperature; Step 202: Establishing a lower-level electricity market clearing model; The electricity market clearing model considers the joint clearing of the energy market and the reserve market, and settles according to the actual market optimization results. The objective function is to minimize the purchase cost of energy and reserve services. In the formula, T and J represent the total number of scheduling periods and the total number of buildings respectively; Among them, the winning capacity and The following constraints must be met: In the formula, Bidding capacity for the aggregator energy market and reserve market, P t E Energy market capacity for all buildings, Spare market capacity for all buildings, are the dual variables of each formula respectively.

3. The method for calculating the marginal contribution of diversified market entities according to claim 2 is characterized by: The specific method of step 3 is as follows: Considering that the lower-level model established above is a linear model, the KKT condition is used to transform the objective function of the lower-level optimization model into the corresponding constraint conditions: Using strong duality theory to linearize the complementary relaxation condition, we get the following formula: The GAMS software BARON solver is used to solve the single-layer mathematical optimization model with equilibrium constraints, and the aggregator's profit and market optimization results as well as the marginal contribution of diversified market players are obtained.

Images