Optimisation of structure and operation of district cooling networks in urban regions

Optimisation of the structure and operation of district cooling networks in urban regions was studied. An optimisation model was developed for cooling networks that comprise a number of cooling consumers with different cooling demands in different period of a year, a number of possible cooling generation plant sites as well as cold media storage sites and a number of possible district cooling pipeline routes. The developed Mixed Integer Linear Programming model was applied for the design of a DC network in an urban region. The consumer cooling demands in the region for the year 2006 and a predicted future data with a number of new potential consumers for the year 2020 were used. From the solutions the structure of the district cooling system including the locations where cooling plants should be built, the cooling capacity of the plants, the cold media storage locations, the storage capacities and the routing of the distribution pipelines to individual consumers was obtained for the two cases. Additionally, the solutions comprise also data for the optimal operation, i.e. how the cooling generation plants will be run in different periods of the year, how the storages will be discharged and recharged and what will be the cold medium flow rates in the district cooling pipelines. The developed model is suitable both for optimisation of district cooling in new regions or for expansions of existing networks.