Commercial buildings in the United States annually consume 15 - 20% of the total national energy production. Approximately 40% of this is used to provide space heating, cooling, ventilation and hot water. The systems that provide this functionality are typically designed and operated using decades-old practices resulting in system-level efficiencies from fuel to end use on the order of 30%. Yet, prototype Cooling, Heating and Power (CHP) systems have been demonstrated to provide efficiencies as high as 80%. If these technologies could be brought from what amount to laboratory demonstrations to the commercial building market the benefits to the nation would be enormous. Technologies such as distributed generation micro turbines, fuel cells, thermally activated heat pumps, integrated electric multifunction heat pumps and high efficiency reciprocating engines are cited repeatedly as vitally important areas in which to focus research and development resources. However, it is also necessary to perform careful and effective integration of these components into coordinated building systems to fully capture the system-level benefits. To meet this challenge the United Technologies Research Center (UTRC), Oculus Technologies of Boston and the School of Architecture at Carnegie Mellon University have come together to establish a model-based systems design methodology that will enable future development of integrated HVAC/R and CHP solutions and advanced building controls. Funded by the National Institute of Standards Advanced Technology Program , the three-year project has as its objectives to:1) Create a model-based systems engineering design process to enable the development of high efficiency integrated HVAC/R and CHP products;2) Establish model-based design methods for energy and building system control;3) Develop IT tools and processes that facilitate industry-wide concurrent engineering of integrated HVAC/R and CHP systems in the commercial building industry. In this talk we will provide an overview of this project, present the integrated concurrent engineering infrastructure and process that we developed for building energy systems, and emphasize the key challenges that represent potential areas of collaboration.