Multi-criteria evaluation of poly-generation system applied to commercial buildings with various prime movers and building types

The present study evaluates the performance of a poly-generation system applied to commercial buildings. An internal combustion engine (ICE) and solid oxide fuel cell (SOFC) used as prime movers represent different efficiency distributions according to part load ratio variation. Accordingly, discrete results are found in terms of energy, environment, and economy depending on the prime mover type applied to each building. A renewable energy system is combined with the poly-generation system, and the outputs produced from the energy generation units are transferred to the energy storage system and supplied to the demand sources. Through the parametric study and hybrid control method, the stored energy is optimally distributed to the cooling and heating system to maximize the primary energy saving ratio. The major components constituting the poly-generation system are modeled and validated based on experiments and literature to enhance the reliability of the dynamic simulation model. The monthly amounts of replenished and wasted energy are examined, and the magnitude of produced energy contribution to the building self-sufficiency ratio is also identified. When ICE- and SOFC-based poly-generations are applied to the hospital, 30.2% and 45.2% of the primary energy consumption is saved, respectively, compared with the conventional system. For the office, the corresponding systems reduce primary energy consumption by 1.8% and 37.2%, respectively. The economic feasibility of the poly-generation systems is examined considering the current energy project in South Korea.