Enhancement of Heat Transfer by Nanofluids in Solar Collectors Santhisree Nerella Department of MECHANICAL Engineering Institute Of Aeronautical Engineering, Hyderabad, India Dr.N.V.V.S.Sudheer Department of MECHANICAL Engineering R.V.R. & J.C.College Of Engineering, Guntur, Andhrapradesh, India Dr. P. Bhramara Department of MECHANICAL Engineering Jntuh .College Of Engineering, Hyderabad, India Abstract- Research and development activities are carried out to improve the heat transfer process to reduce the energy loss, which is an important task in this era of the great demand for energy. The heat transfer process can be improved by means of active and passive techniques .The Heat transfer rates can be enhanced in solar collectors with dispersion of Nanoparticles in to it The advanced research in nanotechnology emerging heat transfer fluids called nano fluids which are colloidal mixtures of nanometric metallic or ceramic particles in abase fluid, such as water, ethylene glycol or oil. Nanofluids possess immense potential to enhance the heat transfer character of the original fluid due to improved thermal transport properties. By using these nanofluids instead of conventional fluids, the heat transfer rate can be increased. Enhancement can be done in heat transfer by conduction, convective heat transfer under both natural and forced flow conditions, and boiling heat transfer in the nucleate regime. Keywords – nanofluids, heat transfer enhancement techniques, solar energy, and solar collector I. INTRODUCTON Solar Energy: A worldwide research and development in the field of renewable energy resources and systems is carried out during the last two decades. As known fossil fuels are expensive, require for a stockroom, combustion of them makes pollution of the atmosphere and resources of fossil fuels in the nearest future will run away .Like an alternative energy sources it is possible to use: biomass, biogas, waterpower, wind energy, geothermal heat and solar radiation. Energy conversion systems that are based on renewable energy technologies appeared to be cost effective compared to the projected high cost of oil. Solar thermal systems are non-polluting and offer significant protection of the environment. The reduction of greenhouse gasses pollution is the main advantage of utilizing solar energy. Therefore, solar thermal systems should be employed whenever possible in order to achieve a sustainable future. Converting the suns’ radiant energy to heat is the most common and well-developed solar conversion technology today. The temperature level and amount of this converted energy are the key parameters that must be known to match a conversion scheme to a specific task effectively. Conversion of solar radiation to other energy forms Fig: 1 Conversion of solar energy Most solar water heating systems have two main parts: solar collector and a storage tank. Solar thermal collector essentially forms the first unit in a solar thermal heat transport fluid. The heat transport fluid delivers this heat to thermal storage tank/boiler/heat exchanger etc system. It absorbs solar energy, converts into heat and then transfers it to be utilized in the subsequent stages of the system. International Journal of Innovations in Engineering and Technology (IJIET) Vol. 3 Issue 4 April 2014 115 ISSN: 2319 – 1058