Numerical Optimization and Energetic Advantages of an Innovative Solar Power System Based on Scheffler Receiver Coupled with Volumetric Expanders

In the current context of increasing public awareness of the externalities of fossil fuel-based energy consumption, improvement in new technologies for energy-saving systems has become a crucial target to reduce both global warming and air pollution. Being motivated by such a critical matter, this study presents an innovative solar thermal plant based on volumetric expanders as work-producing devices coupled with Scheffler solar receivers as a thermal source. Nowadays, Scheffler receivers are well performing owing to high efficiency of the focal receiver which reduce heat losses. Simultaneously, screw expanders are volumetric machines which are able to convert thermal to mechanical power with acceptable efficiency also by expanding vapor-liquid blends at low operating pressures. The numerical model presented in this study evaluates the energetic benefits of the proposed solar power system for various operating situations. Parametric optimization of this solar power plant is then performed in a broad range of operating conditions: the optimum evaporation temperatures, together with the corresponding maximum global efficiencies, were so defined under various solar radiation intensities. The numerical results attained in this research prove that solar electricity generation systems based on screw expanders coupled with the Scheffler receivers are a promising technology.

Evaluating the impact of energy and environment on economic growth in BRI countries

This study investigates the impact of renewable energy consumption (REC), nonrenewable energy consumption (NREC), and carbon emissions on economic growth in 133 Belt and Road Initiative (BRI) countries from 1996 to 2020. We divided our sample into four income groups. For empirical estimation, this study employs panel quantile regression (PQR), and fully modified ordinary least squares (FMOLS) estimation techniques. The results confirm that REC have a positive impact on economic growth and NREC has a negative impact on economic growth. A 1% increase in REC and carbon emissions results in an increase in economic growth of 0.108% and 1.085%, respectively. A 1% increase in NREC reduces economic growth by 0.263% in the full sample countries. There are regional differences, although NREC has a positive impact on economic growth in all income groups in the long run. These novel empirical findings will help policymakers design energy policies to fulfill the target of economic growth in BRI countries.

The moderating role of informal economy on financial development induced ekc hypothesis in turkey

This study conducts an empirical investigation about the moderating role of the informal economy on Turkey's environmental performance by employing advanced econometric techniques that account numerous structural breaks in series. In this extent, we created three interaction variables by captivating the impact of informal economic activities on CO2 emissions through income, energy use, and financial sector development. Besides, we built a main effect model without the interaction variables to assess the direct effects of our variables on global environmental degradation. The outcomes of the carried analyses produced supporting evidence toward the confirmation of the Environmental Kuznets Curve (EKC) assumption. Obtained findings shown that energy use, financial development and the informal economy in Turkey transmit a deteriorating impact on environmental well-being. Furthermore, the moderating role of the informal economy was found to be statistically significant factor in terms of both economic and environmental efficiency.

Energy and exergy analysis of the transient performance of a qanat-source heat pump using TRNSYS-MATLAB co-simulator

In this study, the transient performance of a qanat source heat pump is investigated using a TRNSYS-MATLAB co-simulator. The water/ethylene glycol-to-air compression heat pump and the helical coil heat exchanger, which is used to inject heat to or to extract heat from the qanat water, are mathematically modeled in matrix laboratory (MATLAB), and then, coupled to transient systems simulation (TRNSYS) model to evaluate the system transient performance and calculate the heating and cooling loads of the case study building. Comparison of the performance of the qanat source heat pump with an air source heat pump showed that the coefficient of performance of the qanat source heat pump is at least 5% and at most 34% higher than that of the air source heat pump. By increasing the flow rate of the working fluid in the helical coil heat exchanger from 2 L/min to 8 L/min, the coefficient of performance of the qanat source heat pump increases at least 12% and at most 34.1%. The maximum increase in energy efficiency ratio and free energy ratio of the system by the similar increase in the flow rate is 46.4% and 24.8%, respectively. The exergy analysis of the qanat source heat pump reveals that the minimum and maximum exergy efficiency of the system is 32% and 85.5%, respectively. The findings also indicate that the most exergy destruction occurs in the condenser in heating mode and in the evaporator in cooling mode.

Can the Financial Industry ‘Anchor’ Carbon Emission Reductions?

Existing research is ambiguous about the relationship between the financial industry development scale and carbon emission reduction targets. Therefore, using data from 30 provinces and municipalities directly under the central government (excluding Tibet, Hong Kong, Macao, and Taiwan) from 2009–2018, this study divides the reduction targets into emission quantity and intensity to investigate this relationship. Using the improved STIRPAT equation, the pooled OLS and other estimation technique in robustness test, we found that the financial industry development scale is positively related to emission quantity and negatively related to emission intensity. The financial industry development scale inhibits carbon emission intensity through the mediating role of the technology market development degree, which also has a moderating effect on the scale. The study also discusses the regional differences in the scale's impact on carbon emission intensity, its compensation effect on the economic loss caused by carbon emissions, and the positive influence of policy implementation on carbon emission intensity. We provide suggestions to reduce carbon emissions and achieve carbon neutrality.

Process optimization for the production of biodiesel from Azolla Microphylla oil and its fuel characterization

The most competent and operative use of renewable feedstock is super critical for the production of biodiesel which has increased attention worldwide pertaining to aquatic fern Azolla. Maximizing the biodiesel yield by optimizing the process parameters of the low-frequency ultrasonic energy-assisted transesterification process of Azolla oil is the need of the hour for minimizing the production cost of biodiesel. Response Surface Methodology (RSM) was applied using central composite rotatable design (CCRD) to find the best optimum reaction parameters for this transesterification process. The optimized reaction parameters arrived from the design of experiments were as following: methanol/Azolla oils molar ratio (A) = 6.49 mole/mole, KOH catalyst concentration (B) = 1.69 (weight% of oil), reactiion time (C) = 34.74 min and reaction temperature (D) = 38.87°C. The best higher theoretical predicted Azolla Fatty Acid Methyl Ester (FAME) yield was Y = 99.76% which is in well coincidence with the actual yield. The extracted Azolla biodiesel was tested for various fuel properties with standard test procedures and found to be in agreement with various Biodiesel standards and the results are promising in terms of utilizing Azolla oil as an inexhaustible and potentially economical source of biodiesel.

Analysis of vibrations in a diesel engine produced by Jatropha biodiesel using heterogeneous catalyst

Extensive consumption of fossil fuel has contributed to the worldwide decline of its reserves and detrimental effect on the environment. Therefore, it is essential to explore alternative option of fuel for diesel engine. The main objective of this research article is to optimize vibrations in a single-cylinder variable compression ratio diesel engine driven by Jatropha biodiesel blend. The heterogeneous catalyst (calcium oxide) is used to manufacture of biodiesel from Jatropha curcas oil by a process of transesterification. The optimization technique (Response Surface Methodology) has been employed to optimize root mean square acceleration of vibration by taking load, compression ratio (CR), and fuel injection pressure (FIP) as engine input parameters. Experiments were designed according to central composite design. The amplitude of the frequency domain signals is determined using Fast Fourier Transform and the influence of input parameters has been investigated in the frequency domain analysis of the vibration signatures. The adequacy and significance of the models have been checked by p-value and F value tests. Regression coefficients Adj. R2, R2, Pred. R2 were also found in acceptable range. The experimental outcome reveals that biodiesel yield of 81.6% was obtained at methanol-to-oil molar ratio of 12:1, reaction temperature of 65°C, reaction time of 3 h, and catalyst concentration of 5 wt%. Simultaneously, the model obtained a series of solutions based on the desirability criteria and proposed optimum setting of engine input parameters at a load of 2.59 kg, 17.94 CR, and 268.76 bar FIP for B30 blend. B30 blend generated root mean square acceleration of 4.46 m/s2 at above optimized conditions. A validation trial was conducted and the percentage of error for root mean square acceleration was found to be 2.3356% and 1.3039%, respectively, for B0 and B30 blend.

Amine-Ionic Liquid Blends in CO2 Capture Process for Sustainable Energy and Environment

In the present work, an experiment for CO2 capture process were performed by absorption using various aqueous solvent blends of amine and ionic liquids. The solvent blends were prepared for various compositions by mixing TetraButylAmmonium Acetate [TBA][OAC] and TetraButylAmmonium Bromide [TBA][Br] ionic liquids with Monoethanolamine (MEA). The obtained results were compared with baseline MEA. It was observed that capture efficiency of CO2, absorption rate of CO2 and CO2 diffusion coefficient of MEA-[TBA][OAC] and MEA-[TBA][Br] solvent blends were comparatively higher than baseline 30%MEA. Moreover, the parameters such as density, viscosity, pH, carbon loading and surface tension of all the solvent blends were measured for before and after absorption process. The carbon loading of solvent blends MEA-[TBA][Br] (0.405 mole of CO2/mole of solvent) and MEA-[TBA][OAC](0.459 mole of CO2/mole of solvent) was slightly lower than baseline MEA (0.494 mole of CO2/mole of solvent). However, the viscosity of MEA-[TBA][Br] blends were remarkably lower than MEA-[TBA][OAC] blend and baseline MEA. This might be an important key factor in solvent recovery process with lesser energy demand for sustainable energy and environment.

Thermal performance assessment of a cylindrical box solar cooker fitted with decahedron outer reflector

One of the important issues humankind globally faces in recent years is the scarcity of non-renewable energy resources. Solar energy is considered safe and renewable, which can fulfil the demand and supply chain requirements. Solar box cookers (SBCs) are popular in domestic cooking due to their ease of use and handling. The prime objective of the present work is to develop and test the performance of a cylindrical SBC fitted with decahedron-shaped reflector (CSBC-FDR). The CSBC is designed using minimum entropy generation (MEG) method. Through experiments, we observed that absorber plate attains peak temperature of about 138°C–150°C with the aid of decahedron reflector. The first figure of merit (F1) is found to be 0.13, indicating better optical efficiency and low heat loss coefficient for the SBC. The second figure of merit (F2) is obtained as 0.39, which indicates good heat exchange efficiency (F') and less heat capacity for cooker's interior. The average energy efficiency, exergy efficiency, and standardized cooking power values are 21.93%, 3.04%, and 25.28W, respectively. These results show that the present CSBC-FDR is able to cook food in a shorter period with better efficiency. The experimental and numerical values of overall heat loss coefficient of the developed SBC are in close agreement. The experimentally assessed performance parameters reveal superior performance of the present cylindrical SBC in comparison with many conventional rectangular and trapezoidal box solar cookers.

How solar-based renewable energy contributes to CO2 emissions abatement? Sustainable environment policy implications for solar industry

Renewable energy sources are gaining popularity because they are less expensive and more efficient than traditional energy sources. Using data from 1991 to 2018, we examined the asymmetric impact of solar energy consumption on CO2 emissions in the top-ten solar energy-consumer economies (China, the United States, Japan, Germany, India, Italy, Australia, Vietnam, South Korea, and Spain). Earlier research has used a panel data technique, which has produced consistent conclusions on the solar power–CO2 emissions association, despite the fact that some economies have no evidence of such a linkage. The current study, on the other hand, employs a unique methodology known as “quantile-on-quantile,” which can evaluate time-series dependence in each economy separately to give world yet country-related information for the association among the variables. The findings investigate how quantiles of solar energy consumption quantiles influence CO2 emissions quantiles asymmetrically by giving an appropriate structure to apprehend the whole dependency pattern. The results suggest that, except in Spain and India, solar energy consumption minimizes carbon dioxide emissions at various quantiles. However, the strength of nonlinear association in solar energy–CO2 emissions nexus varies from country to country that needs individual attention and caution for governments in developing the policies related to the solar industry and the sustainable environment.