Effect of mechanical activation on thermal energy storage properties of Co3O4/CoO system

Nekokar, Nariman
Pourabdoli, Mehdi
Hamidi, Ahmad Ghaderi
Üner, Deniz
The heat produced by a solar receiver during on-sun operation can be employed to drive the endothermic reduction reaction of Co3O4 to CoO; then the consumed thermal energy can be recovered completely by the exothermic reverse oxidation reaction of CoO to Co3O4 which can take place during off-sun operation. In this research, the effect of mechanical activation duration (1, 2, 4, 8, and 16 h) on thermal energy storage by Co3O4/CoO redox pair was investigated. It was found that increasing the mechanical activation duration increases the sintering and particle size of the cobalt oxide powder after one cycle redox, and subsequently the thermal energy storage properties are declined. The weight loss was about 4-5 wt.% for samples heated by 1, 3, and 5 degrees C/min, while it was about 2 wt.% for 10 degrees C/min heating rate and less than 1 wt.% for 15 degrees C/min heating rate. The comparison of cycleability of as-received and 1 h mechanical activated cobalt oxide showed that mechanical activation weakens the cycleability of redox reactions of cobalt oxide. The as-received cobalt oxide cycleability continued up to three cycles, although the reduction and oxidation capacities gradually declined. The cycleability of 1 h mechanical activated sample entirely diminished after two cycles. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.


Effect of porosity on the efficiency of DSSC produced by using nano size TiO2 powders
Bilgin, Nursev; Park, Jongee; Öztürk, Abdullah (2014-01-01)
Gözenekliliğin, 20 nm ve 200 nm TiO2 partiküllerinin farklı oranlarda karıştırılmasıyla oluşturulan pastalar kullanılarak hazırlanan boyaya duyarlı güneş pillerinin (DSSC'ler) enerji dönüşüm verimine etkisi araştırılmıştır. Macunların mikroyapısını incelemek için XRD ve SEM analizleri yapılmıştır. DSSC'lerin enerji dönüşüm verimliliği, tam akım yoğunluğu-voltaj eğrisi çizilerek belirlendi. Ağırlıkça% 40 20 nm ve ağırlıkça% 60 200 nm TiO2 partiküllerinden oluşan karışım kullanılarak hazırlanan DSSC,% 6.74'lü...
Effect of Implanted Phosphorus Profile on iVoc Variations During Firing Process of n-type Silicon
Bektaş, Gence; Çiftpınar, Emine Hande; Bütüner, Sümeyye Koçak; Keçeci, Ahmet Emin; Canar, Hasan Hüseyin; Kökbudak, Gamze; Asav, Hasan; Turan, Raşit (2022-08-24)
Electrical activation of implanted phosphorus can be carried out simultaneously with boron dopants at high temperatures or separately at lower temperatures. In this study, we investigate the effect of high and low-temperature annealing processes for dopant activation following the phosphorous implantation process in n-type c-Si. Symmetrically implanted wafers are activated at 875 °C (low temperature) and 1050 °C (high temperature) and subsequently coated with PEC VD SiNx:H. iVoc values of the samples activa...
Effect of changing biomass source on radiative heat transfer during co-firing of high-sulfur content lignite in fluidized bed combustors
Ates, CİHAN; Selçuk, Nevin; Külah, Görkem (2018-01-05)
In this study, effect of changing biomass source on radiative heat transfer during co-firing of high-sulfur content lignite in the freeboard of 300 kW(t) Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) is investigated by using an in-house developed radiation code based on Method of Lines (MOL) solution of Discrete Ordinates Method (DOM). The freeboard is treated as a 3D rectangular enclosure containing gray, absorbing, emitting gas with absorbing, emitting, anisotropically scattering particles surround...
Effect of metal oxide on light oil combustion - TA and kinetic analysis
Kök, Mustafa Verşan (Springer Science and Business Media LLC, 2003-01-01)
Simultaneous thermogravimetry (TG) and differential thermal analysis (DTA) were applied to light crude oil combustion in the presence and absence of metal oxide. In crude oil-limestone mixture, three main transitional stages are detected. These are distillation, low-temperature oxidation (LTO) and high temperature oxidation (HTO) regions respectively. In the case of experiments with Fe(III)chloride at different amounts, the shape of TG-DTA curve is changed considerably. Kinetic parameters of the samples are...
Effect of temperature and membrane preparation parameters on gas permeation properties of polymethacrylates
Guelmues, Serguel Acikalin; Yılmaz, Levent (Wiley, 2007-11-15)
Permeabilities of N-2, Ar, O-2, CO2, and H-2 gases in PEMA (Polyethylmethaerylate) membranes have been measured above and below glass transition in the temperature range of 25-70 degrees C. The permeabilities of the gases were observed increasing with temperature. Arrhenius plot of permeability versus temperature data showed that there is a slope discontinuity at near to T-g of PEMA. In addition, the effects of membrane preparation parameters by solvent casting method (percentage of polymer in solvent, anne...
Citation Formats
N. Nekokar, M. Pourabdoli, A. G. Hamidi, and D. Üner, “Effect of mechanical activation on thermal energy storage properties of Co3O4/CoO system,” ADVANCED POWDER TECHNOLOGY, pp. 333–340, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/43112.