Control of micro-CHP and thermal energy storage for minimising electrical grid utilisation

Combined heat and power (CHP) systems in buildings present a control challenge for their efficient use due to their simultaneous production of thermal and electrical energy. The use of thermal energy storage coupled with a CHP engine provides an interesting solution to the problem – the electrical demands of the building can be matched by the CHP engine while the resulting thermal energy can be regulated by the thermal energy store. Based on the thermal energy demands of the building the thermal store can provide extra thermal energy or absorb surplus thermal energy production. This paper presents a multi-input multi-output (MIMO) inverse dynamics based control strategy that will minimise the electrical grid utilisation of a building, while simultaneously maintaining a defined operative temperature. Electrical demands from lighting and appliances within the building are considered. In order to assess the
performance of the control strategy, a European Standard validated simplified dynamic building physics model is presented that provides verified heating demands. Internal heat gains from solar radiation and internal loads are
included within the model. Results indicate the effectiveness of the control strategy in minimising the electrical grid use and maximising the utilisation of the available energy over conventional heating systems.