scholarly journals Suitability of base liquid in a nanofluid-laden solar flat-plate collector with emphasize on bioglycol

2018 ◽  
Vol 225 ◽  
pp. 04014
Author(s):  
Seyed Reza Shamshirgaran ◽  
Hussain H. Al-Kayiem ◽  
Morteza K. Assadi ◽  
K.V. Sharma

Ethylene glycol and propylene glycol are commonly used as thermal liquids in solar flat-plate collectors (FPCs). They are utilized as base liquid as well as for improving the stability of nanofluids in FPCs. The objective of the present paper is to introduce a renewable-derived bio glycol for use as base liquid in FPCs. The effect of base ratio (BR) of different glycol products on the performance of a conventional FPC and a nanofluidladen FPC is investigated in this paper to determine its suitability. MATLAB programming was employed for modeling the performance of the FPC operating with copper and cerium oxide nanomaterials. The results show that 20:80 bio glycol/water mixture is capable of enhancing the FPC’s energetic efficiency up to 72.1% which is higher than with either ethylene glycol and propylene glycol. The energy efficiency of a glycol-based nanofluid-filled FPC decreases with the base ratio of all three glycol products. Since bio glycol is a non-toxic and safe product, it can be utilized as a safe and environmentally-friend antifreeze and base liquid in nanofluid-filled FPCs.

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
SeyedReza Shamshirgaran ◽  
Morteza Khalaji Assadi ◽  
Hussain H. Al-Kayiem ◽  
Korada Viswanatha Sharma

The evaluation of the performance and characteristics of a solar flat-plate collector (FPC) are reported for domestic and industrial requirements in the existing literature. A computer code was developed using matlab to model and evaluate the energetic and exergetic performance of a nanofluid-based FPC for steady-state and laminar conditions. The analysis was performed using practical geometry data, especially the absorber emittance, for a standard collector. Linear pressure losses in manifolds were taken into account, and a more accurate exergy factor corresponding to a correct value of 5770 K for the sun temperature was employed. The results demonstrate that copper–water nanofluid has the potential to augment the internal convection heat transfer coefficient by 76.5%, and to enhance the energetic efficiency of the collector from 70.3% to 72.1% at 4% volume concentration, when compared to the values with water. Additionally, it was revealed that copper nanofluid is capable of increasing the collector fluid's outlet temperature and decreasing the absorber plate's mean temperature by 3 K. The addition of nanoparticles to the water demonstrated a reduction in the total entropy generation by the solar FPC. Furthermore, increasing the nanoparticle size reflected a reduction in the overall performance of the solar collector.


2017 ◽  
Vol 374 ◽  
pp. 148-156 ◽  
Author(s):  
Montasser S. Tahat ◽  
Ali Cemal Benim

Hybrid nanofluid is the new generation of heat transfer fluid for various heat transfer applications where transport characteristics are substantially higher than the base liquid. The study presents an experimental investigation of rheological and thermophysical properties of Al2O3/ CuO hybrid nanoparticles suspended in 25:75 (by weight) ethylene glycol and water mixture. This manuscript presents experimental work of thermophysical properties of Al2O3/CuO/water/ethylene glycol hybrid nanofluids and its effect on thermal efficiency of flat plate solar collector. Nanofluids of particle volume percentage of 0.5%, 1%, 1.5% and 2% were tested. Results show that thermal conductivity, viscosity and density increases with nanoparticles concentration. The efficiency of the collector was improved by 45% by increasing the nanoparticle weight fraction.


2017 ◽  
Vol 53 (3) ◽  
pp. 222-228 ◽  
Author(s):  
Vidhi Upadhyay ◽  
Rashmi ◽  
P. Himanshu Khadloya ◽  
Y. Raja Sekhar ◽  
A. D Sai Anoop Reddy ◽  
...  

1936 ◽  
Vol 19 (5) ◽  
pp. 773-780 ◽  
Author(s):  
Philip S. Winner ◽  
Carl L. A. Schmidt

1. The solubilities of l-tyrosine, dichloro-l-tyrosine (hydrated), dibromo-l-tyrosine (anhydrous), and diiodo-l-tyrosine in ethanol-water mixtures at 25° have been determined. 2. It was found that the solubilities of the dihalogenated substitution products of l-tyrosine are increased by addition of ethanol up to a certain concentration. Further addition of ethanol leads to a decrease in solubility. The solubility of l-tyrosine is decreased by addition of ethanol. 3. Dichloro-l-tyrosine (hydrated) was found to change to the anhydrous form when allowed to stand in the presence of ethanol. 4. The apparent heat of solution of diiodo-l-tyrosine in an ethanol-water mixture has been determined. 5. The solubility of dl-thyroxine at 30° has been determined in urea solution, ethanol, dioxan, ethylene glycol, and propylene glycol.


2020 ◽  
pp. 48-55
Author(s):  
M.E. Sharanda ◽  
◽  
E.A. Bondarenko ◽  

Ethylene glycol and propylene glycol are important representatives of polyols. On an industrial scale, they are obtained from petrochemical raw materials. Within a decade, significant efforts were made for the producing of polyols from biologically renewable raw materials - carbohydrates. The general trend for carbohydrate hydrogenolysis includes application of liquid-phase process with the use of modified metal-oxide catalysts, at 120-120 ° C and pressure of 3MPa or above. So high pressure is used for the reason to increase hydrogen solubility, and also due to the high partial pressure of low boiling solvents. We supposed that usage of high boiling solvents could allow hydrogenolysis to be performed at the lower pressure. Ethylene glycol and propylene glycol are of particular interest as such kind of solvent since they are both the main products of glucose hydrogenolysis. In this work, the process of hydrogenolysis of glucose and fructose over Cu / MgO-ZrO2 catalyst have been studied at temperature range of 160-200 °C and a pressure of 0.1-0.3 MPa in a flow reactor. The solvents were simultaneously the target products of the reaction - ethylene glycol and / or propylene glycol. Gas chromatography and 13C NMR were used for the reaction products identification. It was found that the solubility of glucose in propylene glycol is 21 % by weight, and in ethylene glycol 62% by weight. It was pointed out that the process of hydrogenolysis can take place at a pressure close to atmospheric. Under these conditions, the conversion of hexoses reaches 96-100 %. The reaction products are preferably propylene glycol and ethylene glycol. The total selectivity for C3-2 polyols is 90-94 %, that is higher than in the hydrogenolysis of glucose in aqueous solution.


Author(s):  
DALWADI M.D. ◽  
NAIK H.K. ◽  
PADHIAR R.D. ◽  
RANA S.S. ◽  
CHAVDA N.K. ◽  
...  

2018 ◽  
Author(s):  
M. T. Nitsas ◽  
I. P. Koronaki ◽  
L. Prentza

The utilization of solar energy in thermal energy systems was and always be one of the most effective alternative to conventional energy resources. Energy efficiency is widely used as one of the most important parameters in order to evaluate and compare thermal systems including solar collectors. Nevertheless, the first law of thermodynamics is not solely capable of describing the quantitative and qualitative performance of such systems and thus exergy efficiency is used so as to introduce the systems’ quality. In this work, the performance of a flat plate solar collector using water based nanofluids of different nanoparticle types as a working fluid is analyzed theoretically under the climatic conditions in Greece based on the First and Second Law of Thermodynamics. A mathematical model is built and the model equations are solved iteratively in a MATLAB code. The energy and exergy efficiencies as well as the collector losses coefficient for various parameters such as the inlet temperature, the particles concentration and type are determined. Moreover, a dynamic model is built so as to determine the performance of a flat plate collector working with nanofluids and the useful energy that can be stored in a water tank. The exergy destruction and exergy leakage are determined for a typical day in summer during which high temperatures and solar intensity values are common for the Greek climate.


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