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Considerable interest is being shown in using biochar production from waste biomass with a variety of disciplines to address the most pressing environmental challenges. Biochar produced by the thermal decomposition of biomass under oxygen-limited conditions is gaining popularity as a low-cost amendment for agro-ecosystems. The efficiency of biochar formation is affected by temperature, heating rate, feedstock type, particle size and reactor conditions. Properties such as pH, surface area and ash content of produced biochar increases with increasing temperatures. Biochar produced at lower heating rates may have high porosity and be beneficial for morphological changes in the soil. Biochar can help to enhance soil health and fertility as well as improve agricultural yield. As a result, biochar can assist in increasing food security by promoting sustainable agricultural systems and preserving an eco-friendly environment. Biochar is also widely being used as a sorbent for organic and inorganic pollutants, owing to its large surface area, allowing it to be immobilized from soil with ease. The functional groups and charges present on the surface of biochar play an important role in pollutants removal. This review focuses on the mechanisms of biochar production using different waste materials as a feed stock, factors that influence biochar quality as well as application of biochar in agricultural soil and their reclamation as well. This article also discusses knowledge gaps and future perspectives in the field of biochar-based toxic-pollution remediation.

Massive adoptions of combined heat and power (CHP) units necessitate the coordinated operation of power system and district heating system (DHS). Exploiting the reconfigurable property of district heating networks (DHNs) provides a cost-effective solution to enhance the flexibility of the power system by redistributing heat loads in DHS. In this paper, a unit commitment considering combined electricity and reconfigurable heating network (UC-CERHN) is proposed to coordinate the day-ahead scheduling of power system and DHS. The DHS is formulated as a nonlinear and mixed-integer model with considering the reconfigurable DHN. Also, an auxiliary energy flow variable is introduced in the formed DHS model to make the commitment problem tractable, where the computational burdens are significantly reduced. Extensive case studies are presented to validate the effectiveness of the approximated model and illustrate the potential benefits of the proposed method with respect to congestion management and wind power accommodation. (Corresponding author:Hongbin Sun)

SunPower Corp. describes its research to develop low-cost, next-generation SunPower modules with 30-year warranties and at least 50% higher energy production per area relative to today's typical multicrystalline Si modules.

Abstract As the adverse effects of global warming become increasingly apparent, the need for low-GWP solutions in the HVAC&R industry is its highest in decades. Alternative working fluids, including natural refrigerants such as Carbon Dioxide (CO2), and high efficiency systems are ways to mitigate the negative environmental impact of refrigeration systems. Researchers have focused on investigating several transcritical CO2 cycles for supermarket and transport applications. Yet, a systematic experimental comparison between multiple advanced cycle architectures is still lacking. To this end, a novel test stand capable of comparing two methods of expansion as well as open-economization at one or both evaporator pressure levels, allowing six cycle configurations that represent much of the state-of-the-art has been developed. Cycle designs, thermodynamic modeling for component sizing, and experimental validation of test stand operation and energy balances are discussed in-depth. Limitations and modifications to the test stand are discussed, as are next steps.

Over the past 30 years, wind power has become a mainstream source of electricity generation around the world. However, the future of wind power will depend a great deal on the ability of the industry to continue to achieve cost of energy reductions. In this summary report, developed as part of the International Energy Agency Wind Implementing Agreement Task 26, titled 'The Cost of Wind Energy,' we provide a review of historical costs, evaluate near-term market trends, review the methods used to estimate long-term cost trajectories, and summarize the range of costs projected for onshore wind energy across an array of forward-looking studies and scenarios. We also highlight the influence of high-level market variables on both past and future wind energy costs.

For the first time, we here propose a green methodology to modify a low bandgap polymer for highly efficient solar cells using atmospheric pressure plasma jet or soft plasma operating on different feeding gases (air, Ar and N2). The physical properties of the modified polymer were investigated using conductivity measurements, UV-visible spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammograms, atomic force microscopy, cathodoluminescence and confocal Raman spectroscopy. Further, we examined the variation of the work function of the polymer before and after plasma treatment using a γ-focused ion beam. Additionally, photovoltaic cells based on the plasma-modified polymer having ITO/PEDOT:PSS/PHVTT (with or without plasma modification):PC71BM/LiF/Al configuration were fabricated and then characterized. We found that the power conversion efficiency (PCE) of the plasma-modified polymer increased dramatically as compared to the control polymer (without plasma treatment). PCE of the control polymer was found to be 4.11%, while after air, Ar and N2 gas plasma treatment the polymer showed PCEs of 4.85%, 4.87% and 5.14% respectively. Thus, plasma treatment not only alters the surface properties, but also modifies the bulk properties (changes in HOMO and LUMO bandgap level). Hence, this work provides new dimensions to explore more about plasma and polymer chemistry.

This report describes experimental studies performed at Carnegie Mellon University to study the parameters that affect the performance of plasma-assisted ammonia radical injection for NO{sub x} control from stationary combustion sources. First, the NO{sub x} reduction potential of hot ammonia injection was studied to determine whether the use of the plasma for radical generation was key to the high NO{sub x} reduction potential of the plasma deNO{sub x} process. It was found that while some of the NO{sub x} reduction in the plasma deNO{sub x} demonstration experiments could be attributed to the enhanced thermal breakdown of NH{sub 3} into NO{sub x} reducing radicals, the effect of using the plasma accounted for 15--35% absolute additional NO{sub x} reduction beyond any thermal benefit. This benefit of using the plasma increases with increased excess air and decreased flue gas temperature. With the benefit of using the plasma verified on the larger scale of a demonstration experiment, two additional experiments were performed to study the parameters that affect plasma deNO{sub x} performance on the local level. The opposed flow experiment failed to produce significant NO{sub x} reduction, although it did highlight some key aspects of plasma performance with ammonia injection. The reverse injection experiment successfully demonstrated the effects of NO-stream temperature, plasma power, and ammonia flow rate on plasma deNO{sub x} performance. Finally, a preliminary study of the chemical kinetics of the plasma deNO{sub x} system was performed. This study highlighted the importance of effective plasma temperature and the residence time of the reagent at that temperature to efficient radical generation.

Abstract A criterion, based on optimization principles, for determining the SAT setpoint in VAV systems is presented. It is generally accepted that conventional SAT reset controls (SATRC), bounded by either space humidity or ductwork size, will save cooling and/or heating energy. How-ever, the ventilation consequences and penalty resulting from increased fan power have generally been overlooked. Ventilation is impacted since changes in the SAT setpoint change the primary airflow rate and the operation of economizer cycles, i.e. the distribution of fresh outdoor air (OA). These changes may result in extra energy demand and ventilation inefficiency if the reset criterion is not appropriate. This optimization concept simultaneously reduces energy consumption and meets ventilation requirements. Simulation results illustrate that the use of the optimized SATRC saves more energy than a conventional one.