The study aims to analyse the heating and cooling demand of the An Najah university campus, and to optimize the building envelope for selected buildings, in order to achieve energy efficiency, and make use of renewable solar energy. Building and urban simulation programs are used to evaluate the effects of applying different technologies and design strategies on the energy consumption. The university campus hosts 11 university buildings. The proposed methodology makes use of an urban energy modelling tool, called CitySim and Design Builder based on EnergyPlus model to analyse the heating and cooling demand of the university campus and assess the solar potential of the site. The energy calculation considers the hourly heating and cooling demand per building, and for the whole campus. The solar irradiation received by the buildings envelope (walls and roofs) consider the impact of the urban environment, including the inter-reflections between buildings and albedo of the outdoor surfaces. The climatic data provided by Meteonorm. The geometrical information of the campus and selected buildings retrieved by GIS while the physical characteristics of buildings are based on on-site previous studies. The results point to the potential for a significant decrease in energy consumption for cooling and heating.