Study On The Operation Optimization Of CCHP Systems Driven By Gas

Built on the concept of energy cascade utilization, CCHP is a distributed energy system which integrates cooling, heating with power generation. It can not only improve the efficiency of energy use, but also protect the environment and reduce the investment cost. Research and application on CCHP system is started relatively late in our country, and the operation effect is not much satisfactory. Thus researching on the operation optimization of CCHP system carefully and deeply is significant for application of the system in our country.The basic configuration of CCHP system driven by gas includes m dynamic units, n translation units, heat recovery unit and supplementary unit. On the premise of meeting the heating, cooling and electric demands, this paper establishes an operation optimization model under the condition of multi-sets configuration with the equipment performance parameters as constraint conditions. By selecting operation cost, exergy efficiency and carbon dioxide emission as the single objective functions and confirming multi-objective functions of optimization based on efficacy coefficient method, this paper forms different operation strategies according to the decision makers. This paper computes the energy consumption of the corresponding objective function through listing all combination forms of the generating electricity of each dynamic unit using enumeration method, and calculating the minimum gas consumption of the complementary unit using interior point method. Afterwards this paper obtain the optimal energy consumption and the objective function values under each of the operating strategy in the GUI of MATLAB through inputting the data of energy price, conversion factor, hourly load data and so on.Taking the internal combustion engine and direct-fired absorption chiller CCHP system in Tianjin as the research object, this paper simulates hourly cooling, heating, electric load of the building using eQUEST, establishes the operation optimization model of the system according to the configuration and the equipment performance of the system, and compares debugging data at the beginning of 2014 with model operation data. According to the comparison, the errors are in the range of ±15% to verify the precision of the equipment operation performance parameters.Under different load case, this paper illustrates running effect of each strategy according to the performance of combustion engine. So the operation of the system should be analyzed in two aspects: the electric load is relatively larger and the cooling load is relatively larger. This paper calculates the energy consumption and objective values of each operation strategy in winter and summer through the operation optimization model, and compares the consequence with that of separate system. The result shows that running effect in summer of this system is better than that in winter which can be shown in the analysis of the operation situation in the typical days. On that basis, this paper analyses the sensitivity of gas, electricity price to the economical operation strategy. And the impact how electricity price sold to the grid affect the economical effect is analyzed in the current energy price.Practical application of the model in the system shows that the model has a universal significance to the CCHP systems driven by gas. This lays the foundation for operation optimization of multi-sets configuration CCHP system.