Optimal lay-out and operation of district heating and cooling distributed trigeneration systems

The paper deals with the optimization of a distributed urban district heating and cooling cogeneration system. The model is based on a Mixed Integer Linear Program (MILP) and includes a set of micro-cogeneration gas turbines and a district heating network potentially connecting each considered building to all the others. Absorption machines, supplied with cogenerated heat, can be used instead of conventional electrical chiller to face the cooling demand. In addition, a district cooling network can be introduced, independently from the district heating one. The objective of the paper is to obtain the optimal synthesis and operation strategy of the whole system, in terms of Total Annual Cost for owning, maintaining and operating the system. The solution has to specify 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 effects of different plant options, comparing cogeneration and tri-generation machines adoption and district heating and cooling pipelines installation, are considered.