Photon management for augmented photosynthesis.

Renewable energy sources have received considerable attention during the past two decades, owing to the advantages in terms of the absence of greenhouse gas emissions, cleanliness, and sustainability. With the growing energy crisis and environmental consciousness, the global perspectives are in the direction of promoting sustainable technologies. The wind and solar energy conversion systems under such a perspective are found very promising. Therefore, these two renewable technologies are the main focus of this chapter.The power electronic converters interfacing play a vital role in the solar and wind energy conversion system with a maximum conversion efficiency. These converters can introduce reliability challenges to the system if not properly designed. A reliability index of a power electronics converter is calculated in terms of design, operation, maintenance, and performance assessment. Generally, the converter failure rate contributes to its overall cost of energy. In this regard, one of the significant challenges facing is reliability.The overall purpose of a reliability analysis is to analyze failure and its impact on systems and to develop a rigid and reliable system.This chapter focuses on the reliability of the used power electronic systems applied for wind energy conversion system (WECS) and solar energy conversion system (SECS).

MOLECULAR EDITING What to watch for in 2022Experts predict next year’s big chemistry research trends ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2021, 99 (45), pp 46–47December 20, 2021Cite this:C&EN 99, 45, 46-47(Credit: C&EN/Shutterstock)Figure1of7Javier García Martínez (Credit: Rive Technology)Figure1of7Vernon Morris (Credit: Jamie Cepernich, Barry Evans Studio, Pinole, CA)Figure2of7Laura-Isobel McCall (Credit: University of Oklahoma)Figure3of7Eugene Y.-X. Chen (Credit: Colorado State University)Figure4of7Corinna Schindler (Credit: Courtesy of Corinna Schindler)Figure5of7Diego Solis-Ibarra (Credit: Courtesy of Diego Solis-Ibarra)Figure6of7Javier García Martínez, president-elect, International Union of Pure and Applied Chemistry“Among all the exciting new trends in catalysis, I would like to mention the photocatalytic conversion of CO2 into useful chemicals. In the last few years, we have seen not only significant improvements in overall CO2 conversion yields, but also in selectivity towards increasingly complex and useful molecules with multiple carbon atoms and a variety of functional groups. Based on the impressive advances in this field over the past few years, I am convinced that during 2022, we will see some significant breakthroughs in terms of what we can do with CO2 using only sunlight to drive its conversion into useful chemicals.”Note: García Martínez is a member of C&EN’s advisory board.Vernon Morris, atmospheric chemist, Arizona State University“The highly publicized social unrest in 2021 inspired calls to the STEM [science, technology, engineering, and mathematics] community to redress the institutionalized systems, mechanisms, and attitudes of exclusion that assure racially biased outcomes in science and technology. Equity-minded scientists will continue to challenge our community to move beyond the status-quo perceptions of who gets to become a scientist and who gets recognition as a producer of knowledge. But if past is precedent, look for heightened backlash against these efforts. Meanwhile, inclusive, interdisciplinary scientific teams will catalyze the development of robust, equity-centered solutions to complex challenges associated with air pollution (particularly in megacities) and environmental justice.”Laura-Isobel McCall, analytical chemist, University of Oklahoma“Now that several new methods have expanded our ability to annotate metabolite features, I am hopeful that scientists beyond the groups that developed these methods will begin to implement them. I will be watching for new biological insights generated from analytical chemistry and computational structure prediction tools. A key step will be increasing confidence in the output of in silico tools, especially with regards to rankings of predicted structures. I also think that we’re all hungry to reclaim the sense of community that was lost during the pandemic. This may lead to a growth in collaborative research projects, with new perspectives on the ‘tough questions.’ ”Eugene Y.-X. Chen, polymer chemist, Colorado State University“The plastics problem is not just about the plastic pollution crisis that everyone witnesses but also about energy and climate change, as plastics manufacturing is predicted to account for 20% of global petroleum consumption and 15% of the carbon budget by 2050. Furthermore, while this is a global problem, R&D activities are not yet globally connected. In 2022, with researchers hoping to travel more freely, we will see a burst of cross-disciplinary, collaborative activities not only in publications but also in international summits and conferences towards our common goal of creating innovative and sustainable solutions to meet this urgent challenge of our time.”Corinna Schindler, synthetic organic chemist, University of Michigan“In organic chemistry, I expect that we will see the trend of skeletal or molecular editing continue to grow. Mark Levin’s young research group at the University of Chicago created a lot of interest earlier this year with their work on skeletal editing through nitrogen deletion. They developed a creative and unexpected approach that got many chemists in the field fascinated. The question is very captivating—can you take a complex molecule and turn it into a very different one (that would take many steps to make) by one simple synthetic transformation? I anticipate that chemists will build on these results to quickly get their hands on new, complex molecules that will have important biological functions.”Diego Solis-Ibarra, materials chemist, National Autonomous University of Mexico “After a little over a decade of excitement and development, 2022 is likely to be the year in which perovskite photovoltaics will finally see the light at a commercial stage. This milestone will surely bring a lot of knowledge, questions, and challenges to the field. Simultaneously, perovskites and perovskite-inspired materials will further venture into new territories beyond solar cells and light-emitting diodes. Frontier applications, such as spintronics, detectors, transistors, and catalysts, are some of the exciting avenues that the field will undoubtedly be exploring.”Learn more in C&EN’s 2022 predictions webinar at cenm.ag/2022predictions.

The conversion of solar energy into electrical current by photosynthetic organisms has the potential to produce clean energy. Life on earth depends on photosynthesis, the major mechanism for biological conversion of light energy into chemical energy. Indeed, billions of years of evolution and adaptation to extreme environmental habitats have resulted in highly efficient light-harvesting and photochemical systems in the photosynthetic organisms that can be found in almost every ecological habitat of our world. In harnessing photosynthesis to produce green energy, the native photosynthetic system is interfaced with electrodes and electron mediators to yield bio-photoelectrochemical cells (BPECs) that transform light energy into electrical power. BPECs utilizing plants, seaweeds, unicellular photosynthetic microorganisms, thylakoid membranes or purified complexes, have been studied in attempts to construct efficient and non-polluting BPECs to produce electricity or hydrogen for use as green energy. The high efficiency of photosynthetic light-harvesting and energy production in the mostly unpolluting processes that make use of water and CO2 and produce oxygen beckons us to develop this approach. On the other hand, the need to use physiological conditions, the sensitivity to photoinhibition as well as other abiotic stresses, and the requirement to extract electrons from the system are challenging. In this review, we describe the principles and methods of the different kinds of BPECs that use natural photosynthesis, with an emphasis on BPECs containing living oxygenic photosynthetic organisms. We start with a brief summary of BPECs that use purified photosynthetic complexes. This strategy has produced high-efficiency BPECs. However, the lifetimes of operation of these BPECs are limited, and the preparation is laborious and expensive. We then describe the use of thylakoid membranes in BPECs which requires less effort and usually produces high currents but still suffers from the lack of ability to self-repair damage caused by photoinhibition. This obstacle of the utilization of photosynthetic systems can be significantly reduced by using intact living organisms in the BPEC. We thus describe here progress in developing BPECs that make use of cyanobacteria, green algae, seaweeds and higher plants. Finally, we discuss the future challenges of producing high and longtime operating BPECs for practical use.

In this chapter, we are focusing on the understanding of the basic characteristics of the Sun and the solar radiation, solar energy conversion, wind velocity, wind power, and wind energy conversion systems, the methods to estimate, analyze, and assess the solar or wind energy resource potential. The solar radiation has directional characteristics that are defined by a set of angles that determine the angle of incidence of the radiation on a surface. After completing this chapter, the readers are able to compute these angles and to estimate the available solar radiation incident on horizontal and tilted surfaces. Wind regime and wind characteristics are influenced by synoptic circulation, mesoscale dynamics, being strongly shaped by the local circulation, topography, and conditions. The most important characteristics of wind are its variability and intermittency on a broad range of spatiotemporal scales. The assessment of wind energy potential, design, or operation of wind energy conversion systems requires in-depth knowledge of wind regime and characteristics. In this chapter, we have also included those topics that are based on the extraterrestrial radiation and the geometry of the Earth and Sun. Knowledge about the effects of the atmosphere on the solar radiation, measurement techniques, direct, diffuse, and global radiation are also presented and discussed. Similar topics, such as wind velocity statistics, wind velocity measurements are included and discussed in this chapter. After successfully completing this chapter, the readers or students have a good understating, and become familiar with solar and wind energy system parameters, characteristics, principles of operation, performances, and estimation methods. They also are able to analyze and perform basic calculations and design of wind energy and/or solar energy conversion systems, estimates and assess wind or solar energy potential, select appropriate systems and/or components for a specific application.

Chapter 10 - An Evaluation of N2 Fixation and H2 Production in Fermentation Culture

Catalyst: Can Systems Chemistry Unravel the Mysteries of the Chemical Origins of Life?

Many approaches to discovering the interaction energy of molecular transition dipoles use the well-known coefficient xi(phi, psi (1) psi (2)) = (cos phi - 3 cos psi (1) cos psi (2))(2), where phi, Psi (1), and Psi (2) are inter-dipole angles. Unfortunately, this formula often yields rather approximate results, in particular, when it is applied to closely positioned molecules. This problem is of great importance when dealing with energy migration in photosynthetic organisms, because the major part of excitation transfers in their chlorophyllous antenna proceed between closely positioned molecules. In this paper, the authors introduce corrected values of the orientation factor for several types of mutual orientation of molecules exchanging with electronic excitations for realistic ratios of dipole lengths and spacing. The corrected magnitudes of interaction energies of neighboring bacteriochlorophyll molecules in LH2 and LH1 light-absorbing complexes are calculated for the class of photosynthetic purple bacteria. Some advantageous factors are revealed in their mutual positions and orientations in vivo.

Experimental investigation on electrical power and thermal energy storage performance of a solar hybrid PV/T-PCM energy conversion system

Solar thermal systems are playing important role to encounter environmental issues like global warming, in the last two decades they replace conventional systems to create an eco-friendly environment. Lot of research have been undergone on solar thermal systems to improve their performance and efficiency, but still the area is wide open for improvement because of demand on renewable sources increase. As their is need for increasing the performance of solar thermal systems, phase change materials could serve as energy storing device during abundant available of energy. For solar thermal systems the major challenge is energy availability will not be round the clock, in order to clear this hurdle phase change materials backing served as a better support. The biggest challenge of developing countries today is to provide clean drinking water, as there are many conventional systems to convert saline water into drinking water their main disadvantage is pollution of environment due to harmful emissions. Hence, solar thermal systems with phase change materials are considered as best option in production of clean drinking water due to their operation by renewable energy, compactness and zero emissions. Phase change materials are coupled with solar system experimentally, and their behaviour and performance were characterized with results and observation, here the phase change material paraffin wax is embedded in copper tubes coupled with solar system is employed in production of clean drinking water; their performance and efficiency are compared with single slope solar still without phase change material. The thermal stability, corrosive resistance and impressive properties of paraffin wax and thermal conductivity of copper were tied together to single slope solar still for improving performance and efficiency of clean drinking water production. It is observed solar still without phase change material could generate drinking water from saline water only during day time, but the solar still coupled with phase change material embedded in copper tubes showed better results with 11 percent increase in production of drinking water even during dark hours.

Solar energy conversion systems are facing the problem of having low optical and thermal performance. The low thermal conductivity of the heat transfer fluid and non-effective optical coating of the solar collector are the main reasons for this. Hence, there is a need to improve the thermal and optical performance of the energy conversion systems. This review paper focuses on the application of nanofluids and nanocomposites for solar collectors operating in low, medium and high temperature ranges, for performance enhancement. A review on applications of nanofluids and nanocomposites shows the desired improvement in thermal and optical properties of solar energy conversion systems from the efficiency and reliability points of view. Solar energy conversion systems play a very important role in the solar energy field, which includes concentrated and non-concentrated systems that convert solar energy into electricity or thermal power. The conversion efficiencies of these systems can possibly be enhanced by using a nanofluid as the heat transfer medium and a nanocomposite as the selective coating.

A Hybrid Electric and Thermal Solar Receiver

This paper presents a two stage, three-phase grid interfaced SPV (Solar Photovoltaic) energy conversion system with an ANF (Adaptive Notch Filter) based control algorithm. The proposed SPV system is a multi-function grid-interfaced solar PV energy conversion system, which along with conversion of dc-power from SPV to AC mains, is capable of reactive power compensation, harmonics current elimination and load balancing in a three-phase AC distribution system. Compared to multiple devices with different functionalities, a multifunction grid-interfaced SPV energy conversion system is capable to save substantially capital investment, space and maintenance cost. The ANF successfully extracts a single sinusoid of a possibly non-stationary nature from harmonics corrupted load currents at PCC (Point of Common Coupling). The control algorithm is adaptive with respect to the fundamental frequency of the system compared to other methods; and provides instantaneous values of the fundamental signals. Simulation and experimental results verify the validity of the presented algorithm and confirms its desirable transient and steady state performances. The THD (Total Harmonics Distortion) of grid currents is found well under IEEE-519 standard even under nonlinear loads.

The vast expansion of available synthetic biology tools has led to explosive developments in the field of materials science. No longer confined to engineering just synthetic materials, the increased accessibility of these tools has pushed the frontier of materials science into the field of engineering biological and even living materials. By coupling the tunability of nanomaterials with the prospect of re-programming living devices, one can re-purpose biology to fulfill needs that are otherwise intractable using traditional engineering approaches. Optical technologies in particular could benefit from capitalizing on untapped potential in coupling the optical properties of nanomaterials with the specificity and scalability of biological materials. This presentation highlights specific applications in optical sensing and light-harvesting energy technologies that exploit the synergistic coupling of nanobio-hybrid materials. We discuss the development of bio-conjugated single-walled carbon nanotubes (SWCNTs) for near-infrared fluorescence sensing and the application of these nanobioptic sensors for continuous measurements in living cells and organisms. We further explore the development living photovoltaics based on bioengineered, photosynthetic organisms with augmented capabilities.

Due to the intermittent nature of sunlight, practical solar energy utilization systems demand both efficient solar energy conversion and inexpensive large scale energy storage. We have developed hybrid solar-charged storage devices called solar flow batteries (SFBs) that integrate photoelectrochemical solar cells with redox flow batteries (RFBs). In these devices, photoexcited carriers collected at the semiconductor-liquid electrolyte interface convert the redox couples to charge up the RFB without external electric bias; which can be discharged to generate the electricity when needed. By matching various silicon solar cells and tandem III-V solar cells (Chem 2018, 4, 2644) with various organic redox couples and optimizing the SFB device design, we improved their round trip solar-to-output electricity efficiency (SOEE) and eventually achieved a record SOEE of 20% with a 500-hour lifetime using high performance tandem perovskite/silicon solar cells (Nature Mater. 2020, 19, 1326). The design principles and the quantitative analysis model for voltage matching solar cells with RFBs (Acc. Chem. Res. 2020, 53, 2611) light up the pathways for achieving even better performance and stability yet maintaining a low cost, which would make these SFBs practical for standalone solar energy conversion and storage systems in remote off-grid locations.

The main objective of this chapter is to address both energy security and power quality improvement, two challenges being faced by the distribution system. The research is focused toward the design, analysis, and implementation of grid-interfaced solar photovoltaic (PV) energy conversion systems. Grid-interfaced solar PV systems can integrate the renewable power of solar PV with the utility grid and simultaneously enhance power quality at their point of common coupling (PCC). As compared to multiple device performing different operations, the proposed solar PV system can save great amount of capital investment and the system space. This also helps in increasing the effective utilization of solar PV energy conversion systems, and the cost recovery is expect to be faster. Simulated results of the presented topology and control for the grid-interfaced solar energy conversion system have been demonstrated and their performances are also reported through simulation and test results. Topology of grid-interfaced PV energy conversion has been studied and success fully implemented in the laboratory. Therefore, in this chapter, the performance of SPV generating systems have been simulated and tested under different operating conditions.