Guest lectures from PPRE-Alumni at Oldenburg University

Guest lectures from PPRE-Alumni at Oldenburg University

Guest lectures from PPRE-Alumni at Oldenburg University

November 2017

Large solar radiation resource assessment initiative in India

by Dr. Indradip Mitra, India (PPRE 2003-04), presently giz India

India has world’s largest pyrheliometric solar radiation measurement network called SRRA (Solar radiation resource assessment). This led to bankable solar and weather database in India. Also a new and improved solar radiation atlas was launched using this data along with satellite derived values. This presentation intends to describe the SRRA network, its composition, quality control, functioning and key applications.


Introduction to the Grid Integration of variable Renewable Energy in India

by Dr. Indradip Mitra, India (PPRE 2003-04), presently giz India

India has a target of 175 GW of renewable energy installation by the year 2022. In this overall plan target of 100 GW is allotted to the grid connected solar domain and 60 GW is dedicated for wind power. Till very recent years the grid connected renewable energy, particularly from variable sources like solar was rather low in India. It was necessary for government authorities to identify important issues in order to resolve the technical, regulatory, financial and market related barriers. Since the year 2013 several actions have been taken and several policy got modified. This presentation intends to provide an overview on the important aspects of this journey towards smooth integration of variable renewable energy.


May 2017

Development of Low Cost Renewable Cooling and Heating Systems for Residential Buildings in Egypt

MSc-thesis project conducted at Research Centre for Sustainable Energy Technology Research at HFT-Stuttgart ( - by Nermeen Galal, Egypt (PPRE 2014-16)

During the EHF-Research Group colloquium at University of Oldenburg, Nermeen presented the findings of her MSc-thesis project at HFT Stuttgart. The aim of her project was to investigate the potential of nocturnal radiative cooling systems for the Egyptian residential buildings. Egypt has been facing an exceeding energy demand since 2011. The cooling demand of the residential sector in Egypt is responsible for the recurrent electricity cut-offs in summer. Radiative cooling to the night sky represents a low-cost renewable energy source. The predominant dry desert climate of Egypt, with clear night skies, promotes radiative cooling applications. The system technology is based on plastic solar absorbers integrated with the building’s hydronic system. With a different control strategy, the same system can also be used for heating applications during winter. The results of this research are simulation-based. The dynamic simulation program TRNSYS17 was used to simulate the transient behavior of the system. Three work-portfolios were considered in this thesis to develop a simulation model for the real system. Firstly, a number of plastic solar absorbers were tested in order to identify their performance parameters. The test was based on the quasi-dynamic test method of the international standard for solar thermal collectors EN ISO 9806:2013. Secondly, a building model, representing a typical residential apartment in Egypt, needed to be developed. For that purpose, a literature review was conducted on recent field surveys and other research-work for residential apartment buildings in Egypt. Finally, a control scheme was designed so that the whole system components collaborate in a proper operation.

Nermeen (introduced by H. Holtorf – left) guest-lecturing at E-lab during EHF Colloquium

The analysis considered the three main different weather conditions in Egypt. Accordingly, the simulation was done for the cities of Alexandria, Cairo and Asyut. The more hot and dry weather conditions result in a higher cooling potential. In Asyut, higher levels of temperature difference could be achieved, and the highest cooling potential was also in Asyut. The simulated cooling power was 28.4 W/m2 for a 70 m2 absorber field. For a smaller field area of 10 m2, the cooling power reached 109 W/m2 in Asyut, but with humble temperature differences. Working in a hybrid system, as a supplementary part to the conventional AC units, a 10% reduction in the active cooling energy demand could be achieved, thanks to the radiative cooling system. This percentage reduction was nearly doubled when the thermal comfort set-point was two degrees higher (26 ◦C). The new Egyptian code for buildings was also investigated as part of the sensitivity analysis of this work. The simulation results proved that the new Egyptian energy standard can independently play a very important role in energy efficiency of buildings.

Contact: Nermeen Galal

(Changed: 2020-01-23)