As　a　promising　approach　for　sustainable　development,　thedistributed　energy　system　receives　increasing　attentionworldwide　and　has　become　a　key　topic　explored　by　researchersin　the　areas　of　building　energy　systems　and　smart　grid.　In　linewith　this　research　trend,　this　paper　presents　a　case　study　ofdesigning　an　integrated　distributed　energy　system　includingphotovoltaics　(PV),　combined　cooling　heating　and　power(CCHP)　and　electric　and　thermal　energy　storage　for　commercialbuildings　(i.e.,　a　hospital　and　a　large　hotel).　The　subsystems　aremodeled　individually　and　integrated　based　on　a　proposed　controlstrategy　to　meet　the　electric　and　thermal　energy　demand　of　abuilding.　A　multi-objective　particle　swarm　optimization　(PSO)　isperformed　to　determine　the　optimal　size　of　each　subsystem　withobjectives　to　minimize　carbon　dioxide　emissions　and　paybackperiod.　The　results　demonstrate　that　the　proposed　method　can　beeffectively　utilized　to　obtain　an　optimized　design　of　distributedenergy　systems　that　can　minimize　environmental　and　economicimpacts　for　different　buildings.　©　2018　ASME.