In this study, we present the activities of Al₂O₃ supported CaO and MgO catalysts in the transesterification of lipid of yellow green microalgae, Nannochloropsis oculata, as a function of methanol ...amount and the CaO and MgO loadings at 50°C. We found that pure CaO and MgO were not active and CaO/Al₂O₃ catalyst among all the mixed oxide catalysts showed the highest activity. Not only the basic site density but also the basic strength is important to achieve the high biodiesel yield. Biodiesel yield over 80wt.% CaO/Al₂O₃ catalyst increased to 97.5% from 23% when methanol/lipid molar ratio was 30.
Decarbonizing the urban environment has two significant challenges: Increasing electricity demand due to the electrification of space heating and increased renewables share in the electricity supply. ...The European Commission defines a new grid support mechanism for peak‐shaving products in renewed Electricity Market Design. This aims to enable a new market tool to stabilize electric supply and demand. This study examines a grid‐integrated thermal storage device's technical feasibility and economic performance to meet net zero building (nZEB) definitions. Alternative scenarios considering current national nZEB targets, present energy market options, and regulations are compared using the life cycle cost and the global warming potentials over the building lifetime. The results show that better building performance is possible even with a low investment increase of 6.7% compared to minimum building standards based on regulations. This enables older building cases to perform similarly with new building targets for Turkish National nZEB. Building electrification using heat pumps and thermal storage systems gives similar economic performances in the long term when a dynamic electricity tariff is available. Adapting the life cycle approach to decision‐making in construction contracts can lead to a 50% decrease in building emissions while staying within the same construction budget.
► CaO/Al
2O
3 single step sol–gel made catalysts for sunflower transesterification. ► Sunflower transesterification at 50
°C. ► Basicity and basic strength using CO
2 temperature programmed ...desorption. ► Volcano plot using turnover frequency and basic strength. ► High turnover frequency does not mean high biodiesel yield at 50
°C. ► 60% CaO/Al
2O
3 has high TOF, 0.028
s
−1, but low biodiesel yield, ∼80%.
The activities of single step sol–gel made calcium oxide on alumina catalysts were studied as a function of CaO loading, methanol/oil molar ratio and the amount of the catalyst in the transesterification of sunflower oil at 50
°C. Also, the turnover frequency (TOF) of the catalysts was calculated to better understand the relationship between the basicity/basic strength and the catalytic activity. From volcano curve (TOF vs. basic strength), it was found that under 50
°C and methanol/oil molar ratio of 9, 60% CaO/Al
2O
3 had the highest turnover frequency, 0.028
s
−1, whereas 85% CaO/Al
2O
3 showed the highest biodiesel yield, ∼96.6%, but TOF obtained on it was 0.012
s
−1. It seemed that 60% CaO catalyst had the proper basic strength to obtain the highest TOF.
•Heat transfer behavior of microalgae panel bio-reactors was investigated.•Effects of reservoir, air layer and reservoir wall thicknesses were studied.•Box-Behnken experimental design method was ...applied for 3 design factors.•The lowest U value was observed as 3.84 W/m2 K.•Most influential factor was observed as air layer thickness of the bio-reactor.
Microalgae has great potential reducing embedded CO2 emissions of buildings through their entire life cycles by both increasing energy efficiency and actively capturing CO2. The use of closed microalgae photo bioreactors as building components has the added benefits of acting as an effective insulation system. Additionally, microalgae can give a dynamic appearance with living dynamic system that also works as an adaptive sunshade. In this study, the thermal transmittance (U value) of different photo bioreactors is determined by using experimental design methods for parametric studies. Heat transfer behaviour of the manufactured panel bioreactors at different operational conditions, which satisfy both thermal comfort in building and microalgae growth conditions, is evaluated. U values between 3.84 and 53.19 W/m2 K are observed in the study. Results show that there is a significant interaction between all main factors (reservoir, air layer, and reservoir wall thicknesses) and U value. Yet a two-way interaction is observed for only between reservoir and air layer thicknesses. Further, air layer thickness has the highest contribution to the U value in the developed model as both a main and synergetic factor.
The activities of single step sol-gel made calcium oxide on alumina catalysts were studied as a function of CaO loading, methanol/oil molar ratio and the amount of the catalyst in the ...transesterification of sunflower oil at 50°C. Also, the turnover frequency (TOF) of the catalysts was calculated to better understand the relationship between the basicity/basic strength and the catalytic activity. From volcano curve (TOF vs. basic strength), it was found that under 50°C and methanol/oil molar ratio of 9, 60% CaO/Al(2)O(3) had the highest turnover frequency, 0.028s(-1), whereas 85% CaO/Al(2)O(3) showed the highest biodiesel yield, ∼96.6%, but TOF obtained on it was 0.012s(-1). It seemed that 60% CaO catalyst had the proper basic strength to obtain the highest TOF.
Increasing renewables in energy mix results in lower emissions but also increased fluctuations in the electricity grid. Current thermal energy conversion-based systems will stay as main electricity ...generation in the grid, and they will support base loads of the system. Whether these systems are fossil or geothermal sourced they need adaptive technologies to harmonize with the changing network. This study aims to investigate feasibility and performance to satisfy response demands for a proposed thermal energy storage system connected to feed stream of thermal power generation to support ancillary services in a case study in Turkey. Tin is selected as the phase change material for its good inductive properties. It is demonstrated numerically that the evaluated heat storage tank, filled with tin, provides adequate time for thermal discharging within time limits to benefit from hourly ancillary power market. Using hourly pricing data for entire 2020, it is found that proposed system shows better economic performance than investment requirement of ROI over 11% as stated in various literature for renewable energy systems. Analysis of system economic performance shows a ROI of 16% and NPV is 17.8% higher than required investment.
The activities of single step sol-gel made calcium oxide on alumina catalysts were studied as a function of CaO loading, methanol/oil molar ratio and the amount of the catalyst in the ...transesterification of sunflower oil at 50 degree C. Also, the turnover frequency (TOF) of the catalysts was calculated to better understand the relationship between the basicity/basic strength and the catalytic activity. From volcano curve (TOF vs. basic strength), it was found that under 50 degree C and methanol/oil molar ratio of 9, 60% CaO/Al sub(2)O sub(3) had the highest turnover frequency, 0.028 s super(-1), whereas 85% CaO/Al sub(2)O sub(3) showed the highest biodiesel yield, similar to 96.6%, but TOF obtained on it was 0.012 s super(-1). It seemed that 60% CaO catalyst had the proper basic strength to obtain the highest TOF.
Historic buildings need to be re-functionalized because of environmental factors, economic reasons, socio-cultural changes. During the re-functionalization-renovation period, only the seismic ...performance of the building is analyzed to sustain the historic building according to law and legislation. However, the historic buildings show a considerable energy saving potential. Therefore, the performance assessment of historic buildings requires multidisciplinary approach, which examines both energy and seismic issues. The study aims to demonstrate how the energy and seismic performance improvement of a re-functioned historic building conducted with an integrated approach based on four phases: 1) evaluating the energy performance of the existing building, 2) determining energy & seismic retrofit packages 3) the energy and cost performance evaluation of retrofit packages 4) analyzing the performance of the retrofit measures. A detailed energy simulations used for finding the effects of energy measures that are passive, active, and their combinations by taking into consideration the historical value of the buildings. Life-cycle cost analysis is applied to find the best retrofit strategy for the historical building case by using the net present value method. The proposed methodology has been applied to a historical building in a Mediterranean City, İzmir to find the best retrofit measures for improving the performance of the building. Results show that the implementation of the external wall and applying the new HVAC system are the most effective measures considering both energy, seismic and cost performance. The study indicates that an integrated approach can improve both energy, seismic and cost performance of the historic buildings.
•Passive, active and combination packages of retrofit measures evaluated to find appropriate energy and cost performance.•Implementation to the exterior wall and HVAC system replacement provides the highest performance.•Seismic and energy retrofit measures show synergistic effect for historical building renovation.•This approach can be applied to the historic building before the re-function/renovation process.
In this study, we present the activities of Al
2O
3 supported CaO and MgO catalysts in the transesterification of lipid of yellow green microalgae,
Nannochloropsis oculata, as a function of methanol ...amount and the CaO and MgO loadings at 50
°C. We found that pure CaO and MgO were not active and CaO/Al
2O
3 catalyst among all the mixed oxide catalysts showed the highest activity. Not only the basic site density but also the basic strength is important to achieve the high biodiesel yield. Biodiesel yield over 80
wt.% CaO/Al
2O
3 catalyst increased to 97.5% from 23% when methanol/lipid molar ratio was 30.
The objective of this study is to investigate crystallite-size effect for oxides of transition metals iron supported on magnesium oxide (MgO) and cerium oxide (CeO2) modified alumina (Al2O3) and the ...effect of the basicity and/or basic strength of support material, on activity and hydrogen selectivity in the steam reforming of glycerol.Crystallite size effect is observed for MgO and Fe on MgO/Al2O3. It is observed that larger MgO crystallites size shifts gaseous product selectivity towards CO. Further as crystallite size is becomes higher than ~5 nm for Fe for gas product selectivity decreases. Basisity has also a similar behaviour; higher basisity or presence of unidentate carbonate basic sites observed at 865 and 800 cm-1 FTIR bands for CeO2 promoted catalysts hinder CO formation and promotes CO2 formation. This also results in high activity of steam reforming. Also basisity studies shows that inorganic carboxylate catalyst site with FTIR band 1535 and 1410 cm-1 is dominantly effective for gaseous product selectivity. High total basisity do not required for high glycerol conversion, yet high total basisity results in high gaseous product selectivity.Considering studied catalysts and their catalytic activities it can be concluded that MgO and Fe modified catalysts shows better activity for syngas production due to their basic and crystalline properties. And CeO2 modified catalysts or MgO catalysts with crystallite sizes lower than 5 nm are shows better performances for CO free product
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