Promotionsvorhaben Doktorand Ahmed Khoja

Towards Net Zero-Energy Neighborhood Retrofitting: A Feasibility Assessment Methodology for Hot Arid Climates

Betreuende Professoren
Prof. Dr. Nathalie Eßig (Hochschule München, Fakultät für Architektur)
Prof. Dipl.-Ing. Thomas Auer (Technische Universität München)

The Building sector contribute to about a third of the total greenhouse gas emissions, consume over 40% of the primary energy and around 30% of the final energy which in turn, makes it the largest energy consuming sector worldwide. Therefore, the built environment and the existing building stock in particular represents the largest untapped source of cost effective energy saving and CO2 reduction.

The proposed dissertation project contributes to the research in the area of Net zero-energy neighborhoods (Net-ZEN) by means of creating a methodology to assess the technical and economic feasibility of retrofitting the existing building stock to reach the Net ZEN status under hot arid climate conditions.

In contrast to the current energy retrofitting approaches the Net-ZEN approach offers a more holistic approach to the issue, as the whole neighborhood is treated as one entity, thus taking advantage of energy saving/production measures that can be only taken at a neighborhood scale (i.e. reduction of the heat island effect, utilization of asphalt solar collectors, district heating/cooling stations, smart grid).

Following this approach the proposed PhD project will investigate and analyze by means of case study analysis the current energy performance of the chosen neighborhood and identify the energy reduction/ production potentials and propose different retrofitting measures in order for the neighborhood to reach the intended Net ZEN status.

The impact of each proposed combination of retrofitting measures on energy consumption/ production rates is then to be analysed by means of computer simulations software. The simulation will be conducted for separate buildings and for the whole neighbourhood along with a cost-benefit analysis for the chosen measures.

The fulfilment of these objectives would lay down the required ground work for the development of a feasibility assessment methodology for reaching the Net ZEN standard in hot arid climates.


  • Developing a feasibility assessment methodology that would contribute to the realization of Net ZEN in hot arid climates.
  • Evaluate the performance of onsite built renewable energy sources and to assess their integration into the existing urban fabric.
  • Evaluate the potential of energy mutualisation between different buildings at the neighborhood.
  • Identifying possible retrofitting measures that can be taken on the scale of a building as well as on the urban scale and to assess their impact on the building and neighborhood in terms of energy consumption.
  • To identify the impact of the urban morphology on the microclimate and to assess its influence on building energy consumption and outdoor temperature as well as on the urban heat island effect.


Ahmed Khoja
Raum: F 206

Tel.: 089 1265-2423
Fax: 089 1265-2630