Gunjo, Dawit Gudeta2019-07-152023-10-262019-07-152023-10-262018ROLL NO.136103030http://172.17.1.107:4000/handle/123456789/1263Supervisors: Pinakeswar Mahanta and P.S. RobiEnergy is an essential requirement for the technological and industrial development of any nation. Among the various energy sources, solar energy and biogas have been identified as clean, safe, sustainable, abundantly available energy source with least environmental constraint. The production of biogas from organic waste is a temperature dependent process. There are three optimum temperature ranges for generating methanogens which is responsible for production of biogas. These are: psychrophilic (≤ 293 K), mesophilic (303 – 313K) and thermophilic (323 K – 333 K).This may be achieved by heating of feedstock in the biogas digester through a heat exchanger in which primary working fluid is water and same is heated with solar thermal collector. Since solar energy varies widely during the day and also dependent on weather as well as season of the year, utilizing the solar energy in continues manner is difficult. Further, geometry, shape and size of the water tubes (riser tube) play an important role in heat transfer. Thus there is a need to undertake detail experimental as well as numerical study on type of collectors (straight and bent tube) on performance of solar water heating system. The fluctuating nature of solar energy restricts its demand for various applications. Integrating the solar collector with the thermal energy storage system (TES) using paraffin wax as phase change material is favourable solution to smoothen the inconsistencyenMECHANICAL ENGINEERINGThesis