Energy is a crucial component of the agri-food sector since almost 30% of the world’s energy is consumed by this sector. Under such circumstances, the employment of renewable energies can be a sustainable solution to mitigate the adverse environmental impacts as consequences of the greenhouse gas (GHG) emissions from the agri-food supply chain. Generation of electricity using photovoltaic (PV) technology to supply the power demand of the agriculture and food production sectors requires large areas of land. To solve this problem, the co-generation of solar PV electricity and crop production (agrivoltaic concept) is expected to relieve this restriction. An emerging agrivoltaic technology is the installation of concentrating PV (CPV) systems in crop cultivation environments to both provide the power demand and produce food on the same land. This study presents an overview of agrivoltaic systems and CPV technology with a special focus on the advent of CPV modules in agricultural environments. In this case, the main benefits and challenges of this technology are presented and discussed.
Co-firing of biomass syngas with pulverized coal under oxygen-rich combustion conditions is an advanced technology that facilitates the utilization of biomass energy and reduces greenhouse gas emissions. Numerical studies were conducted to investigate the characteristics of co-firing of biomass syngas with coal. The effect of biomass syngas injection position on the boiler combustion process when the total heat input to the boiler is stable. The simulation results show that the biomass syngas injection location also has an important effect on the co-combustion characteristics and NOx emissions. NO emissions were lowest when biomass syngas was injected at the bottom of the recombustion zone. This study can provide a reference for the operation and optimal design of biomass syngas cocombustion boilers
Energy consumption not only reflects the level of energy utilizing technology, but also reflects the level of economic development. Since the sudden outbreak of COVID-19 in 2020, world energy consumption dropped drastically. Therefore, the effective energy management is particularly important. In this paper, long short-term memory (LSTM) time series prediction model is used to conduct statistical analysis on the consumption of coal, petroleum, natural gas and renewable energy in the United States. The goal is to analyze the impact of the epidemic based on the consumption statistics from different energy types and predict the trend of energy consumption in the United States. Based on the historical data and LSTM model, it can be concluded that coal and natural gas consumption have obvious jump in the epidemic, while petroleum and renewable energy consumption are relatively stable.
Anion exchange membrane is the core component, and also the key development direction of alkaline fuel cells. In this paper, three popular commercialized anion exchange membranes (Orion 30 μm mechanically reinforced membrane, Orion 5 μm mechanically reinforced membrane, and Alkymer 25 μm membrane) were selected to investigate the effects of different temperature, humidity, stoichiometric ratio and other operating condition factors on the alkaline fuel cell. The experimental results show that the Orion membrane has more stable performance than Alkymer when the cathode stoichiometry ratio changes. The ohmic impedance and activation impedance of the Alkymer membrane decrease as the temperature increases, and thus the operating temperature can be properly increased to improve the fuel cell performance for Alkyme. Humidity change would significantly change the level of membrane hydration, which influences the membrane conductivity. It is also found that the ohmic impedance of Alkymer is more stable than that Orion when the humidity is reduced, and a slight reduction of humidity could improve the fuel cell performance in our experiments.
Modernization of the cooling system for the Data Center is a strategic task aimed at increasing efficiency and reducing costs. The proposed maximum use of the freecooling mode had a positive effect on the operating parameters. The results of the cooling system operation in a transitional climate over two years are discussed.
Hot water huff and puff (HWHP) technology is an effective means to improve the recovery factor (RF) of the tight volcanic reservoir, but the oil recovery effect still needs to be further optimized. In this paper, taking a staged fracturing horizontal well in a tight volcanic reservoir as the object, the influencing factors and optimal design of construction parameters in the process of HWHP were studied by numerical simulation. The results show that the oil production of HWHP is positively correlated with water injection volume (WIV), water injection pressure(WIP), huff and puff cycles(HPC), well soaking time(WST), and fracture density(FD), and negatively correlated with water injection rate(WIR) and water reinjection pressure(WRP). The weight of influencing factor of HWHP from large to small is WRP, FD, HPC, WIV, WIR, WIP, and WST. The best combination of construction parameters of HWHP for a single fractured well in a tight volcanic reservoir is that the FD is 36, WIV is 15000 m3, WIP is 50 MPa, WIR is 300 m3/d, WST is 30 d, HPC is 5, and WRP is 5 MPa. This research can provide an important basis for improving the RF of the HWHP in a tight volcanic reservoir.
Based on the derivation of frequency-domain transfer function, this work obtains natural gas pipelines lumped model directly reflecting the constraints of the inlet and outlet variables. This dynamic model transforms the original partial differential equations into linear lumped constraints of gas transport process and the nonlinear resistance characteristics of pipeline, which can be efficiently solved. Comparing with finite difference method, simulation on single tube and pipeline network indicates that the modeling and solution method proposed in this work has advantages in accuracy and calculation efficiency. On the basis of this method and the topology change caused by leakage, the location optimization calculation can accurately locate the leakage wherever the it occurs in single pipeline or pipeline network with illustrative cases.
Silty-clayey host sediments have been widely identified in natural gas hydrate-bearing sediments (HBS). While the effect of clay (montmorillonite, kaolinite, illite, etc.) on the kinetics of CH4 hydrate formation and dissociation is still not clear. The purpose of this study was to evaluate the kinetics of CH4 hydrate formation and dissociation in sodium montmorillonite (Na-MMT) suspensions with mass fractions ranging from 0.1 wt% to 9.0 wt%. The results indicate that Na-MMT can promote nucleation but delay the growth kinetics of CH4 hydrate, as indicated by the shortened induction time and prolonged reaction time. It is worth noting that as the mass fraction increases, the induction time increases while the rate of gas uptake decreases. The morphological analysis was conducted simultaneously. It was discovered that in the presence of montmorillonite, CH4 hydrate forms initially at the gas-liquid interface and grows upward along the reactor surface. Additionally, the clay-hydrate stratification is evident, indicating that water migrates upward and exacerbates the spatial heterogeneity of CH4 hydrate. The anti-seepage effect on the clay-water interface prevents water from seeping into the clay layer during the dissociation process. These findings have significant implications for understanding the occurrence of CH4 hydrate and developing optimized energy recovery strategies in clay-rich sediments.
Recently, the electric vehicle (EV) has become one of the most interesting next generation mobility technology. However, adoption of the electric vehicle is still limited to new vehicles. One promising alternative solution is to convert traditional engine vehicles into EV. In this study, mobile air-conditioning systems (MACs) of EV conversion are modified by replacing the original rotating compressor with an electrical air-compressor. Bench tests of both the original rotating compressor and the electrical compressor were performed. The results suggest that the original rotating compressor has a cooling performance of 3,927 W and compressing power consumption of 3,060 W, which gives a coefficient of performance (COP) of 1.28, while the new compressor has a cooling performance of 2,163 W and compressing power consumption of 770 W which gives a COP of 2.8. The efficiency of the new electrical compressor is about 2.18 times better than the original mechanical compressor because the mechanical loss of the original compressor was improved.