• Energy Research
• AU close
• AR close

AbstractThis paper shows the experimental study of the thermal efficiency of a counter-flow double-pass solar air heater and the theoretical thermal model developed to describe its thermal behavior. The prototype was designed and manufactured at INENCO, Universidad Nacional de Salta, Argentina, The useful collection area is 2m2, and a channel height of 0.025m. The edge and bottom surfaces are thermally insulated with a 0.05 m thick glass wool layer. The air flow is forced by a tangential fan installed in a 0.18m diameter pipe that is connected to the flow outlet. The collector was mounted with a slope of 40° facing north, in order to maximize the intensity of solar irradiance during winter. Experimental outdoor tests were carried out during a winter period, with maximum solar irradiance on the collector plane around 1050W/m2. A semi-empirical thermal model was developed in order to simulate the air temperature at the collector outlet under different outdoor climatic conditions and air flow. Experimental results and the predictions of the theoretical model were found to be in good agreement.

Abstract Integration of solar photovoltaic (PV) and battery storage systems is an upward trend for residential sector to achieve major targets like minimizing the electricity bill, grid dependency, emission and so forth. In recent years, there has been a rapid deployment of PV and battery installation in residential sector. In this regard, optimal planning of PV-battery systems is a critical issue for the designers, consumers, and network operators due to high number of parameters that can affect the optimization problem. This paper aims to present a comprehensive and critical review on the effective parameters in optimal planning process of solar PV and battery storage system for grid-connected residential sector. The key parameters in process of optimal planning for PV-battery system are recognized and explained. These parameters are economic and technical data, objective functions, energy management systems, design constraints, optimization algorithms, and electricity pricing programs. A timely review on the state-of-the-art studies in PV-battery optimal planning is presented. The challenges, trends and latest developments in the topic are discussed. At the end, scopes for future studies are developed. It is found that new guidelines should be provided for the customers based on various electricity rates and demand response programs. Also, several design considerations like grid dependency and resiliency need further investigation in the optimal planning of PV-battery systems.

La production industrielle d'huile de palme génère simultanément une quantité substantielle de fibres de grappe de fruits vides (EFB) qui pourraient être utilisées comme matière première dans une bioraffinerie à base de lignocellulose. Les sous-produits de la lignine générés par ce processus peuvent offrir des possibilités d'isolation des produits à valeur ajoutée, tels que le p-hydroxybenzoate (pBz), pour aider à compenser les coûts d'exploitation. L'analyse de la lignine EFB par spectroscopie de résonance magnétique nucléaire (RMN) a clairement révélé la présence d'acétate lié et de pBz, la saponification révélant que 1,1 % en poids de l'EFB était du pBz ; avec une teneur en lignine de 22,7 %, 4,8 % de la lignine est du pBz qui peut être obtenu comme composant pur pour être utilisé comme charge chimique. L'analyse de la lignine EFB par RMN et dérivatisation suivie d'un clivage réducteur (DFRC) a montré que le pBz acylate sélectivement le groupe γ-hydroxyle des unités S. Cette sélectivité suggère que le pBz, de manière analogue à l'acétate dans le kénaf, le p-coumarate dans les graminées et le ferrate dans un peuplier transgénique augmenté d'une féruloyl-CoA monolignol transférase (FMT), est incorporé dans la chaîne de lignine en croissance via son conjugué monolignol γ-p-hydroxybenzoylé. L'implication de tels conjugués dans la lignification des palmiers est prouvée par l'observation de nouvelles unités couplées au β-β non résinol p-hydroxybenzoylé dans les lignines. Ensemble, les données impliquent l'existence de p-hydroxybenzoyl-CoA :monolignol transférases qui sont impliquées dans la lignification chez les différents saules (Salix spp.), peupliers et peupliers faux-trembles (Populus spp., famille des Salicacées) et palmiers (famille des Arecacées) qui ont des lignines p-hydroxybenzoylées. Même sans augmenter les niveaux par la sélection ou le génie génétique, les « déchets » actuels de l'EFB d'huile de palme devraient être en mesure de générer un flux important d'acide p-hydroxybenzoïque qui offre des opportunités pour le développement de produits à valeur ajoutée dérivés de l'industrie du palmier à huile. La producción industrial de aceite de palma genera simultáneamente una cantidad sustancial de fibras de racimo de frutas vacías (EFB) que podrían utilizarse como materia prima en una biorrefinería a base de lignocelulosa. Los subproductos de lignina generados por este proceso pueden ofrecer oportunidades para el aislamiento de productos de valor agregado, como el p-hidroxibenzoato (pBz), para ayudar a compensar los costos operativos. El análisis de la lignina EFB por espectroscopía de resonancia magnética nuclear (RMN) reveló claramente la presencia de acetato unido y pBz, y la saponificación reveló que el 1,1% en peso del EFB era pBz; con un contenido de lignina del 22,7 %, el 4,8 % de la lignina es pBz que se puede obtener como un componente puro para su uso como materia prima química. El análisis de la lignina EFB por RMN y la derivatización seguida de escisión reductora (DFRC) mostró que pBz acila selectivamente el grupo γ-hidroxilo de las unidades S. Esta selectividad sugiere que pBz, análogamente con acetato en kenaf, p-cumarato en gramíneas y ferular en un álamo transgénico aumentado con una feruloil-CoA monolignol transferasa (FMT), se incorpora a la cadena de lignina en crecimiento a través de su conjugado de monolignol γ-p-hidroxibenzoilado. La participación de dichos conjugados en la lignificación de la palma se demuestra al observar nuevas unidades no acopladas a β-β-resinol p-hidroxibenzoiladas en las ligninas. Juntos, los datos implican la existencia de p-hidroxibenzoil-CoA:monolignol transferasas que participan en la lignificación en los diversos sauces (Salix spp.), álamos y álamo temblón (Populus spp., familia Salicaceae) y palmeras (familia Arecaceae) que tienen ligninas p-hidroxibenzoiladas. Incluso sin mejorar los niveles mediante mejoramiento o ingeniería genética, los 'desechos' actuales de aceite de palma EFB deberían ser capaces de generar una corriente considerable de ácido p-hidroxibenzoico que ofrezca oportunidades para el desarrollo de productos de valor agregado derivados de la industria de la palma aceitera. The industrial production of palm oil concurrently generates a substantial amount of empty fruit bunch (EFB) fibers that could be used as a feedstock in a lignocellulose-based biorefinery. Lignin byproducts generated by this process may offer opportunities for the isolation of value-added products, such as p-hydroxybenzoate (pBz), to help offset operating costs. Analysis of the EFB lignin by nuclear magnetic resonance (NMR) spectroscopy clearly revealed the presence of bound acetate and pBz, with saponification revealing that 1.1 wt% of the EFB was pBz; with a lignin content of 22.7 %, 4.8 % of the lignin is pBz that can be obtained as a pure component for use as a chemical feedstock. Analysis of EFB lignin by NMR and derivatization followed by reductive cleavage (DFRC) showed that pBz selectively acylates the γ-hydroxyl group of S units. This selectivity suggests that pBz, analogously with acetate in kenaf, p-coumarate in grasses, and ferulate in a transgenic poplar augmented with a feruloyl-CoA monolignol transferase (FMT), is incorporated into the growing lignin chain via its γ-p-hydroxybenzoylated monolignol conjugate. Involvement of such conjugates in palm lignification is proven by the observation of novel p-hydroxybenzoylated non-resinol β–β-coupled units in the lignins. Together, the data implicate the existence of p-hydroxybenzoyl-CoA:monolignol transferases that are involved in lignification in the various willows (Salix spp.), poplars and aspen (Populus spp., family Salicaceae), and palms (family Arecaceae) that have p-hydroxybenzoylated lignins. Even without enhancing the levels by breeding or genetic engineering, current palm oil EFB 'wastes' should be able to generate a sizeable stream of p-hydroxybenzoic acid that offers opportunities for the development of value-added products derived from the oil palm industry. ينتج الإنتاج الصناعي لزيت النخيل في الوقت نفسه كمية كبيرة من ألياف مجموعة الفاكهة الفارغة (EFB) التي يمكن استخدامها كمادة وسيطة في مصفاة حيوية تعتمد على اللجينوسليلوز. قد توفر المنتجات الثانوية لليجنين الناتجة عن هذه العملية فرصًا لعزل المنتجات ذات القيمة المضافة، مثل p - hydroxybenzoate (pBz)، للمساعدة في تعويض تكاليف التشغيل. كشف تحليل اللجنين EFB بواسطة مطياف الرنين المغناطيسي النووي (NMR) بوضوح عن وجود أسيتات مرتبطة و pBz، مع كشف التصبن أن 1.1 ٪ بالوزن من EFB كان pBz ؛ مع محتوى اللجنين بنسبة 22.7 ٪، 4.8 ٪ من اللجنين عبارة عن pBz يمكن الحصول عليه كمكون نقي للاستخدام كمادة وسيطة كيميائية. أظهر تحليل اللجنين EFB بواسطة NMR والاشتقاق متبوعًا بالانقسام الاختزالي (DFRC) أن pBz يعمل بشكل انتقائي على أسيتيل مجموعة γ - hydroxyl من وحدات S. تشير هذه الانتقائية إلى أن pBz، بالتناظر مع الأسيتات في الكناف، و p - comarate في الأعشاب، و ferulate في حور معدّل وراثيًا معززًا بـ feruloyl - CoA monolignol transferase (FMT)، يتم دمجه في سلسلة اللجنين المتنامية عبر γ - p - hydroxybenzoylated monolignol conjugate. ثبت تورط مثل هذه المترافقات في ترصيع النخيل من خلال ملاحظة وحدات p - hydroxybenzoylated غير الراتينول β - β المقترنة في اللجنين. معا، تشير البيانات إلى وجود p - hydroxybenzoyl - CoA: monolignol transferases التي تشارك في تبييض في الصفصاف المختلفة (Salix spp.)، الحور والحور (Populus spp.، عائلة Salicaceae)، والنخيل (عائلة Arecaceae) التي تحتوي على p - hydroxybenzoylated lignins. حتى من دون تعزيز المستويات عن طريق التكاثر أو الهندسة الوراثية، يجب أن تكون "نفايات" زيت النخيل الحالية قادرة على توليد تيار كبير من حمض p - hydroxybenzoic الذي يوفر فرصًا لتطوير منتجات ذات قيمة مضافة مشتقة من صناعة نخيل الزيت.

Abstract Two new codes for calculating with space and energy details in the resonance region are presented here: RMET21 and RMET22. The first one is for homogeneous mixtures and pin cells and the second for cluster type fuel elements. The methods used in these codes are based on the solution of the integral form of the Boltzmann transport equation, with first-flight collision probabilities. Resonance profile tabulations are used, constructed from basic evaluated nuclear data files. In the RMET21 program, there is an option to calculate resonance cross-sections with the Breit—Wigner formula, using any set of resonance parameters. This option is useful, e.g. in comparisons with analytical methods and to make sensitivity studies. In the RMET22 code, a new procedure is presented in the resonance region, using collison probabilities, without the approximation of annularization, commonly used to deal with this geometry. In the RMET22 code, the different pins and other regions within a cluster of rods are treated allowing for the details of space and energy. A new method is used to obtain collision probability tables for interpolations and other approximations to speed up the calculations. Comparisons of results obtained by different treatments and experiments are included, showing the accuracy of the methods presented here and their applicability.

Abstract The upward energy demand, along with the depletion of conventional energy sources, demands improved utilization of renewable energy resources. Among all renewable energy resources, solar energy is the most appropriate alternative to conventional energy sources owing to its inexhaustibility and green property. Solar collectors are devices that convert solar radiation into heat or energy. However, the efficiency of the solar collector is still not adequate. The competent step to enhance the efficiency of the solar collector is to use nanofluids. This study is carried out different phases viz. characterization and stabilization while both qualitative and quantitative methods used to evaluate the stability of nanofluids thermophysical properties of Al2O3 and CNC nanofluids such as thermal conductivity measured at four different temperature using KD2 Pro, viscosity and specific heat determined at similar temperature range by viscometer and differential scanning calorimetry respectively. The experiment is executed with a fixed flow rate and in steady-state conditions under extensive solar radiation. The experimental study has revealed that up to 2.48% and 8.46% efficiency of solar collector enhanced by using 0.5% Al2O3 and 0.5% CNC nanofluids respectively. Moreover, nanofluids show good to moderate stability performance. Besides, the thermal conductivity of nanofluids increased while viscosity is in a decreasing trend with increasing temperature. Nanofluids could enhance the efficiency of a flat-plate solar collector.

Our aim was to model the current and future potential global distribution of Chloris truncata (windmill grass) based on the plant's biology, soil requirements and colonisation success. The growth response of C. truncata to constant temperatures and soil moisture levels were measured and estimated respectively, to develop parameters for a CLIMEX bioclimatic model of potential distribution. The native distribution in eastern Australia and naturalised distribution in Western Australia was also used to inform the model. Associations with soil types were assessed within the suitable bioclimatic region in Australia. The global projection of the model was tested against the distribution of soil types and the known successful and failed global introductions. The verified model was then projected to future conditions due to climate change. Optimal temperature for plant development was 28°C and the plant required 970 degree-days above a threshold of 10°C. Early collection records indicate that the species is native to Queensland, New South Wales and Victoria. The plant has been introduced elsewhere in Australia and throughout the world as a wool contaminant and as a potential pasture species, but some of the recorded establishments have failed to persist. The CLIMEX model projected to the world reflected effectively both the successful and failed distributions. The inclusion of soil associations improved the explanation of the observed distribution in Australia, but did not improve the ability to determine the potential distribution elsewhere, due to lack of similarity of soil types between continents. The addition of a climate change projection showed decreased suitability for this species in Australia, but increased suitability for other parts of the world, including regions where the plant previously failed to establish.