A building load model for the electricity consumption of the KIER (Korea Institute of Energy Research) complex was developed by compiling the year-round hourly data of each member building. Heating and cooling load models for the complex were also estimated by building TRNSYS models for the member buildings. By matching measured data that are only available for a limited time on a building, suitable parameter values for the TRNSYS simulation were empirically determined. Then, an operational simulator that can accommodate arbitrary combinations of energy producing devices was developed. Our simulator allows for prioritization among the energy supplying devices, and cases where photovoltaic (PV) and solar thermal devices are mixed can be easily simulated. Several scenarios were composed for the KIER buildings. Tested components include small to medium-size conventional cogeneration systems and renewable energy production devices such as photovoltaic cells, solar collectors, fuel cells, and bio-ORC (organic Rankine cycle). Tests reveal that our tool produces reasonable results of physical quantities such as electricity production, fuel consumption, and the device operational characteristics. Scenario comparisons were made as a preliminary part of a feaSibility study, and renewable energy contribution was estimated. (C) 2017 Elsevier B.V. All rights reserved.