Development of efficient district cooling systems: The modelling approach of the INDIGO project

Cooling demand in buildings is globally increasing, therefore developing more efficient cooling systems is important for the sustainability of European cities. Directive 2012/27/EU of the European Parliament and of the council on energy efficiency states: "Member States should carry out a comprehensive assessment of the potential for high-efficiency cogeneration and district heating and cooling". The EU project INDIGO is investigating this issue considering also the economic efficiency and the use of renewable energy sources. In a district cooling system different kinds of cooling production can be combined. E.g., the use of absorption chillers with waste heat or through the solar cooling or the use of free cooling (generally the heat is rejected to seas, lakes, rivers or waterways) offer the possibility of a more sustainable way of cooling. Controlling those systems in an efficient way is a complex problem (consider that the cooling demand is much more difficult to predict than the heat demand, particularly the peaks, and sources such as the solar energy and the waste heat are not predetermined by the designers). The present paper focuses mainly on the development of dynamic energy models and on their use in the context of the project.