International Journal of Innovative Research in Engineering & Science ISSN 2319-5665 (June 2013, issue 2 volume 6) 66 Design Study of Nanofluid Solar Absorption Refrigeration system Farhan Lafta Rashid (1) , Muhammad Asmail Eleiwi (2) , Hisham Assi Hoshi (3) (1) Ministry of Science and Technology (2) Lecture, Tikrit University, College of Engineering (3) Lecture, University of Technology Abstract Solid metallic materials, such as silver, copper and iron, and non-metallic materials, such as Alumina, CuO, SiC and carbon nanotubes, have much higher thermal conductivities than heat transfer fluids (HTFs). It is thus an innovative idea trying to enhance the thermal conductivity by adding solid particles into HTFs and can be used as heat transfer media in the solar absorption refrigeration system. AgO nanofluid with weights percent of 0.1, 0.2, 0.3 and 0.4%, which compared in the ability of transfer and storage the heat with distilled water, it is found that the suitable weight percent was 0.1 wt%. The flow rate required supplying heat input to generator and the volume of hot fluid storage required to operate the refrigerator for 24 hours has been calculated. Experimental and theoretical results obtained from the present work show a good improvement by comparing with literatures. Keywords: Nanofluid, Absorption Refrigeration System, Energy Storage, Heat Transfer, Heat Capacity. Introduction Generally, nanofluids are formed by dispersing nanometer-sized particles (1-100 nm) or droplets into HTFs. Nanoparticles have unique properties, such as large surface area to volume ratio, dimension-dependent physical properties, and lower kinetic energy, which can be exploited by the nanofluids. At the same time, the large surface area make nanoparticles better and more stably dispersed in base fluids. Compared with micro-fluids or milli-fluids, nanofluids stay more stable, so nanofluids are promising for practical applications without causing problems mentioned above. Nanofluids well keep the fluidic properties of the base fluids, behave like pure liquids and incur little penalty in pressure drop due to the fact that the dispersed phase (nanoparticles) are extremely tiny, which can be very stably suspended in fluids with or even without the help of surfactants[1]. The concept of nanofluid is not new as in 1857 Michael Faraday first reported the study on the synthesis and colors of colloidal gold, but it was possible to put it into practice only after the tremendous development of nanotechnologies during the last decade1. The mixture of suspended nanoparticles in a base liquid is usually referred to as a nanofluid. Nature is full of nanofluids, like blood, a complex biological nanofluid where different nanoparticles (at molecular level) accomplish different functions, and functional components actively respond to their local environment. According to the types of liquids (organic and inorganic) and kinds of nanoparticles, one can get different types of nanofluids like process extraction nanofluids, environmental (pollution-controlling nanofluids), bio-, and pharmaceutical nanofluids. A new class of polymer nanofluids, drag-reducing nanofluids, aim at enhanced heat transfer, as well as, flow friction reduction. A wide range of active self-assembly mechanisms for nanoscale structures start from a suspension of nanoparticles in fluid. Addition of nanoparticles in liquid remarkably enhances energy transport process of the base liquid2. Modern nanotechnology