# Analysis of Nanofluids Behavior in Concentrated Solar Power Collectors with Organic Rankine Cycle
###### Abstract
The review article provided comprehensive information for the design of a solar thermal system working at the different operating conditions. The enhancement of the thermal properties of various high-temperature nanofluids for solar thermal energy storage application in concentrating solar power (CSP) systems, the thermo-physical properties of the heat transfer fluids (HTF), and the thermal energy storage (TES) materials were studied and presented by reference [14]. In this study, silica (SiO\({}_{2}\)) and alumina (Al\({}_{2}\)O\({}_{3}\)) nanoparticles, as well as carbon nanotubes (CNT), were dispersed into a molten salt and a commercially available HTF. Dimensional analyses and computer simulations were performed to predict the enhancement of thermal properties of the nanofluids. A model was presented by [PERSON] [18] for the analysis of thermodynamic cycle of the solar thermal production of power, heating and cooling utilizing nanofluid as a working fluid in Organic Rankine Cycle. The initial studies in reference [18] were performed with silver-nano pentane as a working fluid in the cycle. An available modeling program was used by this reference to model and investigate the performance of the system with nano organic fluid. This paper concluded that under optimum conditions, the thermodynamic efficiencies were higher than those obtained from the base fluid. Reference [19] reported and analyzed high-temperature parabolic trough collectors (PTC) coupled with an Organic Rankine Cycle (ORC) to carry out optimization at both levels: financially and energetically. They investigated the solar field, the storage tank and the ORC module under many conditions of collecting solar areas and storage tank volumes. They also presented an economic comparison for different commercial solar collectors. [PERSON] and [PERSON] [20] studied the performance of Parabolic Trough Solar Collector (PTSC)-based power generation plant, the effect of adding an Organic Rankine Cycle (ORC), and a Thermal Energy Storage (TES) system and the most efficient fluid on the performance and financial metrics of the PTSC-power plant. The simulation results of this paper showed that Benzene is the most efficient organic fluid, having the highest thermal and exergetic efficiency, and the lowest pumping power when compared to other organic fluids. Finally, thermodynamic modeling of ORC was reported in the literature by [PERSON] et al. [21], [PERSON] [22; 23], and [PERSON] [24] where low- and high-grade waste heat is converted into power. In this paper, we present a numerical model to simulate and study the behavior of heat transfer fluid with different nanofluids circulating in the parabolic trough solar collector loop to drive an Organic Rankine Cycle with patent quaternary refrigerant mixture, under different solar radiations. The model is based upon the mass and energy equations written for the heat transfer fluid with nanofluids. These equations were integrated and solved to predict the behavior of the parabolic trough collectors (PTC) coupled with an Organic Rankine Cycle (ORC) under different operating conditions such as solar radiations, nanofluid flow rates, ambient temperatures, and various volumetric nanofluid concentrations. This study is intended to investigate the enhancement effect and characteristics of nanofluids Al\({}_{2}\)O\({}_{3}\), CuO, Fe\({}_{3}\)O\({}_{4}\) and SiO\({}_{2}\) in an integrated concentrating solar power (CSP) with ORC, and TES under different solar radiations, angle of incidence, and different nanofluids concentrations. Also, the objectives of this study are to investigate impact of the nanofluids Al\({}_{2}\)O\({}_{3}\), Fe\({}_{3}\)O\({}_{4}\), CuO and SiO\({}_{2}\) on the CSP solar collector performance compared to thermal oil base fluid under study at similar conditions. This research represents a significant contribution to the nanofluid science where nanofluid are nanofluids are used to enhance performance of CSP solar collectors and integrated ORCs compared to thermal oil as base heat transfer fluid.