Optimization of Distributed Trigeneration Systems Integrated with Heating and Cooling Micro-grids

The paper deals with the influence of the amortization period in the optimization of a distributed urban district heating and cooling trigeneration system. The model, presented in detail in [1], is based on a Mixed Integer Linear Program (MILP) and includes a set of micro-cogeneration gas turbines for producing electricity and thermal energy and a set of absorption chillers, driven by cogenerated heat, for producing cooling energy. Micro-gas turbines and absorption chillers can be used instead of purchasing electricity from the grid, producing thermal energy by boilers and cooling energy by compression chillers. Moreover, various building can be connected each other through a district heating and cooling network (DHC network). The optimization specifies the kind, the number and the location of cogeneration equipment and absorption machines, the size and the position of district heating and cooling pipelines as well as the optimal operation of each component. The objective function takes into account investment cost of micro-gas turbine, absorption chillers and DHC network, maintenance costs, operation costs and any income from the sale of electricity. The aim of the paper is to obtain the optimal solution varying the amortization period of machines and networks, for understanding the influence of capital costs on the annual total cost, the optimal system configuration and operation.