A novel energy system which serves public buildings with large interior zones was proposed in this study. The proposed system integrates a modified water loop heat pump (WLHP) with a natural-gas-fueled SOFC plant. The distributed SOFC plant is employed to complete the conversion from chemical energy to electricity and heat, and the modified WLHP which retrieves the waste heat of the SOFC plant is used for space cooling or heating. A "standards-oriented" model was built, and an "as-designed" approach was adopted to estimate the performance of the WLHP. For understanding the energy saving potential and CO2 emission reduction of the proposed system, a reference system, representative of the general level of energy production and consumption, is brought about for comparison. The LEER (integrated energy efficiency ratio) and CO2 emission trend show that the proposed system offers a much higher primary energy efficiency and realizes an obvious CO2 emission reduction compared to the reference system. Although the estimate of the IEER and CO2 emission reduction is conservative for some imperfections of the built models, the results of this study will still help significantly in guiding China's future CO2 emission reduction efforts. (C) 2018 Elsevier Ltd. All rights reserved.