Development of a simulation model of transient operation of micro-CHP systems in a microgrid

This paper presents the development of a simulation tool for modeling the transient behavior of micro-CHP systems, equipped with both thermal and electric storage units and connected with both electric and district heating grid. The prime mover considered in this paper is an internal combustion reciprocating engine, which is currently the only well-established micro-CHP technology. Different users, characterized by different demands of electric and thermal energy, both in terms of absolute value and electric-to-thermal energy ratio, are analyzed in this paper. Both summer and winter hourly trends of electric and thermal energy demand are simulated by using literature data. The results present a comprehensive energy analysis of all scenarios on a daily basis, in terms of both user demand met and energy share among system components. The transient response of the prime mover and the thermal energy storage is also analyzed for the two scenarios with the lowest and highest daily energy demand, together with the trend over time of the state of charge of both thermal and electric energy storage.