摘要:This paper studied the retrofit project of an existing office building in Beijing to meet the requirements of nearly zero energy buildings. The office building is the first retrofit nearly zero energy building project in China. There are technical difficulties under the constraints of the building and resources. In order to study the technical solutions applicable to the project, we analyzed the suitability of different energy-saving technologies based on the resources and characteristics of the project. Then we obtained the key energy-saving factors. This paper also discussed the energy saving effects of different energy efficiency technology solutions, proposing an optimized nearly zero energy technology solution and verifying the energy-saving level of the optimized plan. Compared with normal new constructions complied with national energy efficiency standard, the energy efficiency of this retrofit building increased by 60%.