A mixed-integer linear programming (MILP) model for the evaluation of CHP system in the context of hospital structures

In this paper an optimal planning method is proposed for sizing a cogeneration plant to be installed within a public/commercial micro-grid. The optimization tool is based on a mixed integer linear programming model which uses a set of experimental input data in terms of both thermal and electric power consumption for determining the annual operational strategy, able to reach a twofold objective: minimizing the total operational cost of the micro-grid and finding the optimal size of the CHP to be installed. A numerical example arisen from a case study is proposed with the aim of investigating the economic advantages coming from the adoption of an optimal cogeneration operation strategy. Two different scenario problems exploiting a set of experimental data have been investigated. The former focuses on the comparison between a micro-grid wherein the cooling energy demand coming from final users is neglected and a micro-grid wherein the cooling energy demand is taken into account. The latter assesses the effect of a heat storage properly introduced into the micro-grid, once the cooling energy demand is taken into account.