Trade-off between environmental and economic objectives in the optimization of multi-energy systems

An increase in the energy and environmental performance of building system can be found in a design that allows the operators to choose between multiple energy sources. Such a system can be referred to as multi-energy system and recently a strong interest was put in this topic at both district and building levels. Since multi-energy systems use non conventional aggregation of energy sources, new energy converters, and unusual system layouts, it is of the foremost importance to provide modelling and optimization procedures for those systems. In this paper, some objective functions based on a set of economic and environmental criteria are defined and used to perform the system optimization. The relations between the outcomes of the optimizations are then analyzed on a case study as a function of the customer, the energy costs, and the pollutants emissions showing that there is generally a trade-off between environmental and economic objectives.