Nowadays, carbon neutrality becomes a long-term goal for many countries all over the world. In order to reach the final goal, carbon neutral, it requires people to reduce the fossil fuel energy consumption and carbon dioxide emission. Distributed energy systems (DES) have received an increasing attention from the researchers and governments. However, despite the previous DES studies on various distributed energy resources and systems from different aspects, the integration and design optimization issues have not been investigated sufficiently. In this paper, a multi-objective optimization in terms of life cycle environmental and economic impacts is proposed to obtain an optimal design of distributed energy systems for different building types in various climate regions. Several typical distributed energy technologies are considered in this paper including combined heat and power system (CHP), solar photovoltaic (PV), solar thermal collector (STC), wind turbine (WT), as well as battery energy storage (BES) and thermal energy storage (TES). The building types under investigation are hospital, large office, and large hotel. The proposed multi-objective optimization is applied to determine the best combination of distributed energy technologies as well as the system size for different locations building types. Results show that the proposed optimization method can be applied to obtain an optimal design of distributed energy systems for different building types in different climate zones and reach a balance between the life cycle environmental and economic impacts.