Analysis of Nanofluids Behavior in Concentrated Solar Power Collectors with Organic Rankine Cycle

Abstract

In this paper, the performance of nanofluids in a Parabolic Trough Concentrating Solar Collector (CSP)-based power generation plant, an Organic Rankine Cycle (ORC), and a Thermal Energy Storage (TES) system is studied. 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 integrated concentrating solar power (CSP) with ORC, and TES under different solar radiations, angles of incidence, and different nanofluid concentrations. The refrigerant mixture used in the ORC loop to enhance the ORC efficiency is an environmentally sound quaternary mixture composed of R134a, R245fa, R125, R236fa. The results showed that the power absorbed, and power collected by the CSP collector and thermal energy stored in the storage tank are enhanced with the increase of the solar radiation. It was also found that the CSP hybrid system efficiency has been enhanced mainly by the increase of the solar radiation and higher nanofluid concentrations over the thermal oil as base fluid. Also, the study concludes that the nanofluid CuO outperforms the other nanofluids-Al 2 O 3 , Fe 3 O 4 and SiO 2 -and has the highest CSP solar collector performance compared to the other nanofluids and thermal oil base fluid under study at similar conditions. Finally, it was found that the model's prediction compares fairly with data reported in the literature; however, some discrepancies exist between the model's prediction and the experimental data.Appl. Syst. Innov. 2019, 2, 0022 2 of 26 Rankine Turbine generator (ORC) using refrigerant, where electricity is generated [1,7]. Thermal energy storage is an integral part of a CSP plant in order to overcome the intermittency of solar radiations for continuous production of power during the night and on cloudy days [8,9].Nanofluid is a mixture of an HTF and nanoparticles and can be used to enhance the thermo-physical properties of HTF. Recently, it was proposed in references [10-18] to nanofluids as a heat transfer fluid in solar power collectors, and to investigate their optical properties, which are essential to the phenomenon of direct energy absorption. The results reported in these references showed that the maximum allowable temperature at which the absorption coefficient does not change significantly is as high as 500 • C. This makes metal-oxide nanoparticles suitable for use at very high temperatures in heat transfer fluids in CSP plants.Heat transfer fluids with nanoparticles provide significant benefits in CSP solar power plants because of the enhancement of heat transfer, thermodynamic and thermophysical properties in absorbing heat induced by solar radiation. Enhanced heat transfer by the use nanofluids yields improvement to the receiver performance and absorption efficiency that may reduce the number of CSP collectors required to produce power using the basis fluid as thermal oil [28][29][30][31][32][33][34][35].It has been shown theoretically and experimentally that, in low-temperature solar collectors at around 100 • C, ef...

Analysis of Nanofluids Behavior in a PV-Thermal-Driven Organic Rankine Cycle with Cooling Capability

“…It is belived that this is attributed to the fact that the nanolfuid CuO has higher thermo-physical properties compared to the other nanolfuids, including water as the heat transfer fluid. Due to the lack of experimental data published in the literature on the new concept presented hereby, to validate our numerical model, the predicted values of the efficiency of the ORC cycle at the specific conditions reported in this study were compared with what has been published in the literature on low-temperature applications of ORC , namely Sami [5][6][7]16,28], and were found to be in fair agreement with these references and Demirkaya et al [11] and Goswami [12]. In addition, the PV solar panels efficiency values reported elsewhere in this paper were also found to be in agreement with what has been published, namely, Faragli [8], and Sami [24][25][26].…”

“…The following thermal analysis was performed for the PV cell; however, it is assumed that all PV cells behaved the same; therefore, it was applied to the PV solar panel. The heat absorbed by the PV solar cell can be calculated by the following [6,[24][25][26][27]:…”

“…The solar photovoltaic panel is constructed of various modules and each module consists of arrays and cells. The dynamic current output can be obtained as follows [6,[24][25][26][27]:…”

“…The AC power is calculated using the inverter efficiency η inv , output voltage between phases, neutral for single-phase current I o and cosϕ as follows [6,[24][25][26][27]:…”

“…Nowadays, the organic rankine cycle (ORC) has become an important technology for recovering waste heat, heat from renewable heat source for improving thermal performances. This technology is manly used for low temperature and low-grade energy resource [6,7,18]. ORC can be integrated with 2 of 21 different working thermal power plants such as a combined gas-steam power plant, a solar-integrated combined cycle, a solid oxide fuel cell, geothermal, biomass or combination of these hybrid power plants to be used as a heat source to ORC.…”