摘要： Owing to how effectively it can convert solar energy into usable form, solar thermal technology has gained a lot of importance during the recent years. Heat exchangers, refrigeration, air conditioning, material science engineering, etc. are the biggest proponents incorporating solar technology along with nano particles for their high thermal conductivity. This study concerns with the effect of water based Al2O3 Nano fluid on the performance of solar water heater- Flat plate type. In the study, the dispersion quality of nanoparticles in fluid was enhanced using high quality surfactant sodium dodecyl sulfate (SDS). The experiments were conducted at Amity University Rajasthan, Jaipur, India (27.1721° N, 75.9542° E) which has an annual average solar irradiance 5.56 kWh/m2/day. Different conditions like flow rate, pressure, climatic conditions, time, solar collector inclination angle, composition of Nano fluid etc. were tested. The Al2O3 concentration varied from 0.1 to 0.3 vol. percentage. The tests were performed at different mass flow rates 1-3 LPM. The measured values of the thermal conductivity in the range of 0.610-0.622 W/m-k. Results indicated that by increasing the volume fraction of Al2O3 from 0.1% to 0.3%, there is a 21.32% growth in collector efficiency.