A novel control strategy for optimizing combined cooling, heating, and power systems with energy storage devices in commercial buildings

The prime mover within a combined cooling, heating, and power system is responsible for supplying the dominant energy to a building and satisfying energy demands neither insufficiently nor excessively according to the control strategy applied to the system. However, there are extremely limited control strategies that consider the dedicated heat-to-power ratio and include multiple energy storage devices in the control domain for prime mover and renewable energy systems. The present study proposes an innovative control strategy that controls the user's energy demand to precisely match the heat-to-power ratio between the energy demand and supply hourly and maintain a specific stored energy level of active energy storage devices through control mode differentiation. This control allows for the maximum utilization of energy produced by prime mover and renewable energy systems, thereby improving overall system performance. The solid oxide fuel cell-based combined cooling, heating, and power system coupled with the developed control strategy exhibits the best system performance and the highest system utilization rate with the lowest reliance on supplemental energy sources and the lowest wasted energy compared to the baseline control strategy. In addition, it reduces the primary energy consumption, carbon dioxide emissions, and annual total costs by 52.4%, 49.0%, and 13.3%, respectively, compared to the conventional system. Finally, the performance of the new control strategy is examined with different building and prime mover types, and it still exhibits advantages over the baseline control strategy.