Sheela K. Ramasesha Ph.D

Divecha Centre for Climate Change,

Indian Institute of Science

Email: sheela@caos.iisc.ernet.in

Tel:  +91-80-2293-3427

Fax:       080-2293-3425

Research Interest

Renewable energy and climate change research

• Involved in basic and applied research in renewable energy technologies

Projects:

• Rail Coaches with Rooftop Solar Photovoltaic Systems: The performance of solar photovoltaic modules mounted on the rooftop of a rail coach of The Indian Railways is reported here. The focus of this experiment was to quantify the reduction in diesel consumption of the end-on generation system that powers the electrical load in the new generation coaches. A coach retrofitted with two flexible solar photovoltaic modules was run at speeds up to 120 km/h by coupling it to three popular trains of south India, namely, Chennai-Coimbatore-Chennai Shatabdi Express, Chennai-Mysore-Chennai Shatabdi Express and Chennai-Bangalore-Chennai Double Decker Express. Based on the experimental results, the benefits of operating solar rail coaches is projected. It is estimated that one solar rail coach can generate atleast 18 kWh of electricity in a day, leading to an annual diesel saving of 1700 litre. The Indian Railways operates 63,511 coaches and hence, under ideal conditions, can save around 108.5 million litre of diesel annually. This would help to control environmental pollution and mitigate climate change, as it reduces the carbon dioxide emission by 2.9 million tonnes in a year. A statistical model was developed to estimate the power output per unit rooftop area of the coach, to enable The Indian Railways to calculate the benefits of operating solar rail coaches on various routes..


• 20 kWp Solar Photovoltaic System : A 20 kWp Solar Photovoltaic (SPV) system was set up on the library roof-top in Indian Institute of Science, Bangalore, India. This roof-top photovoltaic (RTPV) system partly powers the Central Office of IISc. The system has been producing an average daily yield of approximately 80 kWh for the past two years which translates to an annual yield of 28.9 MWh. The main objective of setting up this SPV system is to study the performance of solar plants under different seasons and climatic conditions of Bangalore. Forecast models to predict the performance and yield of the SPV system are also being developed using the data collected from the system..


• Electric buses v/s Diesel buses : The performance analysis of an electric bus procured by Bangalore Metropolitan Transport Corporation (BMTC) was carried out. The performance of this electric bus was compared with the performance of diesel bus being operated in the same route. The study concluded that the introduction of electric buses as a means of public transport in the city would be beneficial both economically as well as environmentally.


• Fabrication of semi-transparent solar cells : Low cost processes for making thin film solar cells is being developed. The envisaged application for these cells is for windows and skylights of buildings. Transparency in visible wavelength of solar radiation is critical for these applications. Thin film deposition of both n-type and p-type semiconductor is carried out using optimized solutions. The main advantage of this process is that in addition to being a cost effective process it is possible to deposit large area solar cells.


• CPV testing and simulation for Indian weather conditions: We, in collaboration with Imperial College, London, UK, set up Concentrated Photovoltaic (CPV) modules on a dual-axis sun tracker on Divecha Centre rooftop to study the effect of atmospheric conditions like aerosols, temperature and water vapour on the power output. In addition to CPV modules, a polycrystalline silicon flat panel is also mounted on the sun tracker and the power output of this panel is being monitored.


• Charging an ultra capacitor with solar power : 12 V / 250 F Substrate-integrated lead-carbon hybrid ultracapacitors (SI-lead-carbon HUCs) with polymeric silica gel electrolyte, which is the hybrid of lead-acid battery and electrical double-layer capacitor (EDLC). Due to the quick charging character of the ultracapacitor, even on cloudy days the charging was complete. This work was done in collaboration with Prof. A.K. Shukla, SSCU, IISc.