How to improve peak time coverage through a smart-controlled MCHP unit combined with thermal and electric storage systems

Abstract

In this study, we assessed the performance and suitability of a mini/micro combined heat and power (MCHP) unit combined with thermal and electric energy storage systems. Local generation of energy, complemented with storage of the energy during times of high supply and the discharge of stored energy during periods of high demand, can aid in increasing self-sufficiency and independence from suppliers for electrical energy users. Furthermore, reducing general electricity demand at peak times does not only make the national electricity grid more resilient as a whole, but also potentially reduces associated electricity costs for the consumer.Analyses were based on data obtained from an MCHP test stand at the Technology Centre Energy of the University of Applied Sciences Landshut, Germany. The MCHP system consists of generic components, which are all currently available on the market, but operated using an improved in-house systems control logic. We found that incorporating an electrical energy storage (EES) system has significant impact on balancing instantaneous supply and demand. It also ensures considerably longer MCHP unit run times. The EES stores 25–50% of the total MCHP-generated electricity and receives excess electricity during 70–95% of the total MCHP run time. Furthermore, we identified a minimum daily number of MCHP unit run times and electrical energy storage recharging cycles, both of which are associated with a high level of self-sufficiency. At least two MCHP unit run time cycles, each lasting approximately 3–3.5h, resulted in self-sufficiency in excess of 80%. Improvements to the current system control logic are proposed, which could result in higher levels of self-sufficiency, as well as in enhanced electrical demand coverage during peak time.