Abstract

Modeling the water content in soil is important for the development of agricultural information systems. Various data are necessary for such modelling. In this paper the authors are proposing a methodology for a frequent situation, i.e., when the modeler is facing a problem due to the lack of available data. Soil water prediction, e.g., for irrigation planning, should be performed with a daily time step. Unfortunately, past measurements of soil moisture, which are necessary for the calibration of a model, are often not available at such a frequency. In the case study presented the soil moisture data were acquired every two weeks. The authors have tested a model utilizing the Random Forests (RF) algorithm, which was used for the conversion of the original data to data with a daily time step. The accuracy of the application of RF to this task is compared with a neural network-based model. The testing accomplished shows that the RF algorithm performs with a higher degree of accuracy and is more suitable for this task.

Abstract

This study proposes a green way to design Plug Flow Reactors (PFR) that use biodegradable polymer solutions, capable of contaminant retaining, for industrial wastewater treatment. Usually, to the design of a reactor, the reaction rate is determined by tests on a Continuous Stirred-Tank (CST), these generate toxic effluents and also increase the cost of the design. In this work, empirical expressions (called “slip functions”), in terms of the average concentration of the contaminant, were developed through the study of the transport behaviour of CrVI into solutions of xanthan gum. “In situ” XRμF was selected as a no-invasive micro-technique to determine local concentrations. Slip functions were used with laboratory experiments planned in similar conditions using Plug Flow Reactors, to obtain useful dimensionless parameters for the industrial design.

Abstract

The energy consumption associated with domestic hot water supply services correspond to a significant portion of the total energy consumption of the urban water cycle. The objective of this study is to analyse the performance of domestic water heaters in the three largest cities of Australia (i.e. Sydney, Melbourne and Brisbane). The performance of systems was investigated undertaking a multi-parametric analysis, in which energy efficiency indicators (i.e. energy intensity and power peaks) were combined with level of service indicators (i.e. compliance rate with minimum temperature thresholds for end use points and hot water tanks). The operation of water heaters was modelled using the software EnergyPlus. Results demonstrate the need for a more holistic approach for the design and assessment of domestic water heaters taking into account not only the technology type to heat water, but also site specific aspects.

Abstract

Kathmandu is one of the fastest growing cities in South Asia facing various challenges related to climate change, local pollutants emissions and energy security of supply. This study analysed the greenhouse gas mitigation potential in different economic sectors of the city by using Long-range Energy Planning (LEAP) frame work. It shows that the effect of implementing various low carbon development strategy options can reduce 35.2% of total greenhouse gas emission from energy use as compared to the base case scenario in 2030. This indicates the need for exploring the possibility of utilizing the global climate funds and adopting voluntary mechanisms for greenhouse gas mitigation. The estimated demand side technology investment cost of low carbon measures for different sectors ranges from less than USD 1/tonne CO2e for residential sector to USD 99/tonne CO2e for transport sector. The low carbon options also results co-benefits in terms of significant reduction in emission of local pollutants and improvement of energy security. As Government of Nepal has envisioned following low carbon economic development path on the long run, there is the need of establishment of regulatory framework, institutional framework and development of clear action plans for realizing the implementation of low carbon development strategy measures in the country.

Abstract

The paper analyses dependence of water quality parameters on flow rates at several sites in the Vltava River catchment in the Czech Republic. The presented results indicate that at the monitored sites, concentrations of nitrates, suspended solids and dissolved oxygen are in direct relation to flow rate. Temperature has an inverse relationship to flow rate. Other parameters show various relationships to flow rate at individual monitored sites or do not show any statistically significant relations.

Abstract

The energy demand of the corn-based bioethanol production could be reduced using the agricultural byproducts as bioenergy feedstock for biogas digesters. The release of lignocellulosic material and therefore the acceleration of degradation processes can be achieved using thermal and mechanical pretreatments, which assist to hydrolyze the cell walls and speed the solubilization of biopolymers in biogas feedstock. This study is focused on liquid hot water, steam explosion and ultrasonic pretreatments of corn stover. The scientific contribution of this paper is a comprehensive comparison of the performance of the pretreatments by fast analytical, biochemical, anaerobic digestibility and biomethane potential tests, extended by energy consumptions and energy balance calculations. The effectiveness of pretreatments was evaluated by means of soluble chemical oxygen demand, biochemical oxygen demand and by the biogas and methane productivities. The results have shown that the thermal pretreatment, steam explosion and ultrasonic irradiation of biogas feedstock disintegrated the lignocellulosic structure, increased and accelerated the methane production and increased the cumulative biogas and methane productivity of corn stover in reference to the control during mesophilic anaerobic digestion. The energy balance demonstrated that there is an economical basis of the application of the liquid hot-compressed water pretreatments in a biogas plant. However, the steam explosion and ultrasonication are energetically not profitable for corn stover pretreatment.

Abstract

Increasing global warming and decreasing fossil fuel reserves have necessitated the use of renewable energy resources like solar energy in India. To maximize returns on a solar farm, it has to be set up at a place with high solar radiation. The solar radiation values are available only for a small number of places and must be interpolated for the rest. This paper utilizes Artificial Neural Network (ANN) in interpolation, by obtaining a function with input as combinations of 7 geographical and meteorological parameters affecting radiation, and output as Global Solar Radiation (GSR). Data considered was of past 9 years for 13 Indian cities. Low values of error and high values of coefficient of determination thus obtained, verified that the results were accurate in terms of the original solar radiation data known. Thus, ANN can be used to interpolate the solar radiation for the places of interest depending on the availability of the data.

Abstract

Biomass productivity presents a challenging problem in arid and semi-arid areas.  Despite a large need for energy in the form of solid biomass, liquid fuel or needs for animal feed, these regions remain largely unproductive.  A convenient way to overcome this challenge is to utilize plants with high water-use efficiency.  Agave lechuguilla is an example of a highly productive (3.8 tons ha^-1 yr^-1 ) desert plant that holds the potential for producing biomass with minimal water resources.  For this purpose, a global suitability map has been developed showing areas where this plant can be planted, and its productivity was assessed.  A Maxent model was used and was further refined by excluding protected areas and used lands (urban, agriculture, etc..).  Productivity assessment provides a good way forward for prioritizing the regional utilization of this plant.   This study provides an initial analysis for the use of arid and semi-arid regions for biomass production.  Results indicate the potential generation of 93.8 million tons per year of dry biomass if the suitable areas were fully utilized.  The analytical method can be readily applied to other potential plant species to optimize the use of certain areas.

Abstract

The heat pump water heater is one of the most energy efficient technologies for heating water for household use. The present work proposes a simplified model of coefficient of performance and examines its predictive capability. The model is based on polynomial functions where the variables are temperatures and the coefficients are derived from the Australian standard test data, using regression technics. The model enables to estimate the coefficient of performance of the same heat pump water heater under other test standards (i.e. US, Japanese, European and Korean standards). The resulting estimations over a heat-up phase and a full test cycle including a draw off pattern are in close agreement with the measured data. Thus the model allows manufacturers to avoid the need to carry out physical tests for some standards and to reduce product cost. The limitations of the methodology proposed are also discussed.

Abstract

Indonesia is facing challenges on the lack of electricity access in rural areas and the management of agricultural waste. The utilization of waste-to-energy technology can help in mitigating these issues. The aim of this paper is to assess the economic viability of a biomass gasification system for rural electrification by investigating its competitiveness in relation to various government supports. Financial modelling is applied to calculate Net Present Value (NPV), Internal Rate of Return (IRR), and Levelized Cost of Electricity (LCOE). NPV and IRR results indicate that biomass gasification is an economically viable option when appropriate financial government supports exist. LCOE result indicates that biomass gasification system is already more economically competitive compared to diesel generator even without additional support but it is less competitive compared to the national electricity grid tariff. In conclusion, the biomass gasification system is an economically viable option for rural electrification in Indonesian context.

Abstract

Nowadays, the use of mobile telephony and wire-less devices has become more demanding, generating electromagnetic radiations. Microwave radiation can affect the growth rate of plants. For this study, the aromatic plants i.e. parsley, celery, dill, basil, were chosen as irradiated plants. This study aims to investigate the effects of irradiation with microwave field on polyphenolic compounds from basil, celery and parsley. The extracts were obtained by sonication. Quantitative analysis of polyphenolic compounds was performed by high performance liquid chromatography using an Altima C18 column. The elution was performed in gradient, with acetonitrile (eluent A) and formic acid in water (1%, eluent B). It was observed that in the irradiated plants, the content of polyphenolic compounds was higher than in the controlled plant. This finding suggests that that plants were strongly influenced by stress due to electromagnetic fields.

Abstract

The intention of this research was to select the ideal condition for accelerated aging of bio-oil and the consequences of additive in stabilizing the bio-oil. The bio-oil was produced from the catalytic pyrolysis of empty fruit bunch. The optimum reaction conditions applied to obtain the utmost bio-oil yield were 5 wt% of H-Y catalyst at reaction temperature of 500 °C and nitrogen flow rate of 100 ml/min. A 10 wt% of solvents including acetone, ethanol, and ethyl acetate were used to study the bio-oil’s stability. All the test samples were subjected to accelerated aging at temperature of 80 °C for 7 days. The properties of samples used as the indicator of aging were viscosity and water content. The effectiveness of solvents increased in the following order: acetone, ethyl acetate, and 95 vol% ethanol. Based on the result of Gas Chromatography-Mass Spectrometry (GC-MS), it could impede the chain of polymerization by converting the active units in the oligomer chain to inactive units. The solvent reacted to form low molecular weight products which resulted in lower viscosity and lessen the water content in bio-oil. Addition of 95 vol% ethanol also inhibited phase separation.

Abstract

The present paper consists of two parts. In the first part the interface delamination of bi-material structures (unit cell of wind rotor blade) with different material properties under mechanical loading at physical conditions – electricity, temperature and moisture is under consideration. The investigation of the above mentioned structures are motivated by the importance for safety of devices used for energy industry applications. The second part is devoted to renovation of old buildings by using new and modern composite materials. The goal is to find via mathematical modelling the safety zone, the reliability of the structures considered and the detection of possible interface delamination as a function of geometrical, material and physical parameters as well as the pull-out force of modern composites used in building industry. The analysis provided in both parts is based on the modified shear lag method. The results obtained in the first and second parts of the paper are illustrated by tables and figures. Some recommendations and possible criterions are proposed, as well.

Abstract

The goal of this work is to find a solution for disposal of Vitroplast FR4, a material found in waste printed circuit boards. In this study, the influence of addition of Vitroplast, generated by mechanical treatment of printed circuit boards waste on concrete properties such as compressive strength was investigated in laboratory conditions. By substitution of filler (i.e. sand) in a mass ratio of 5, 10, 15 and 20% with Vitroplast in concrete mixture, the compressive strength decreased into 57.5, 84.5, 95.0 and 95.9%. The results of leaching tests have shown that by incorporating Vitroplast in concrete mixtures in a 10% mass ratio, the elution of arsenic and cadmium is below the limitations prescribed for inert wastes. The studied approach offers the possibility for environmental friendly recycling of printed circuit boards.

Abstract

Various types of hybrid drives are increasingly being applied in transportation. Wing sails can provide additional propulsion to a motor-driven ship, thereby decreasing fossil fuel consumption. This article contributes to the selection and consideration of the influencing parameters for applying wing sails for ship propulsion. Basic developmental factors and application of wing sails are described. In addition, influential parameters and their relations are discussed. These parameters are connected to the physical and mechanical properties of wing sails and their impact on propulsion. It is important to recognize certain contributions of every influential parameter in relation to the final achievement. Parameters are ranked and described for several common types of sails, to find the best solution. Changing values of the influencing parameters on wing sails can significantly increase converted wind energy. The aim of this study was to note the parameters that influence the wing sail to drive ships more efficiently. Their importance is explained in an example based on the two most important sail types. This article evaluates the main parameters for a pointed semi-rigid wing with additional circulation for hybrid propulsion. All further research should be focused on this wing. Finally, guidelines for structural and operational changes in future wing sails are provided, which may assist developers in directing their efforts to discover a better solution for ship propulsion.

Abstract

The Journal of Sustainable Development of Energy, Water and Environment Systems - JSDEWES is an international journal dedicated to the improvement and dissemination of knowledge on methods, policies and technologies for increasing the sustainability of development by de-coupling growth from natural resources and replacing them with knowledge based economy, taking into account its economic, environmental and social pillars, as well as methods for assessing and measuring sustainability of development, regarding energy, transport, water, environment and food production systems and their many combinations. In total 32 manuscripts were published in Volume III, all of them reviewed by at least two reviewers. The Journal of Sustainable Development of Energy, Water and Environment Systems would like to thank reviewers for their contribution to the quality of the published manuscripts.

Abstract

The indoor visual comfort of subjects faced with indoor ambient lighting varies with the position of the subject and is not constant over time. Average performance indexes, such as the mean value of Daylight Factor and Daylight Autonomy, are commonly used to analyse lighting distribution. These indexes, however, don’t properly take into account either the spatial or the time distribution of values affecting the non-uniformity of environmental lighting. Indeed, these are limited to the definition of a mean value or to the assessment of time availability of daylighting. This paper examines spatial and temporal non-uniformities in indoor lighting as possible causes of discomfort for occupants. The goal is to propose and verify possible supplementary tools to integrate traditional methods of evaluating ambient indoor lighting. Use of the entropy theory with a probabilistic approach can help to obtain more detailed information about the environment. The authors have developed a case study of several sample environments and have analysed the relationships between lighting parameters and typical indices of information theory. Results show that this approach could be a useful way for predicting possible indoor visual comfort issues and for developing a preliminary assessment to a sustainable building design.

Abstract

Municipal solid waste was collected from Varanasi’s municipal solid waste dumpsite and sorted for organic fraction present in it. Current work showed the consequences of calcium hydroxide or lime digestion on organic fraction of municipal solid waste of Varanasi, India. The organic fraction of municipal solid waste sample was digested with desired amount of calcium hydroxide. The different concentrations (0.1, 0.2, and 0.5%) of calcium hydroxide was blended separately to substrates (10% total solid) at 30-35 °C in 3 different beakers denoted by A1, A2 and A3, respectively of 2 L capacity. Experiments of hydrolysis step were conducted on all three samples for evaluation of chemical oxygen demand, pH and volatile fatty acids content in sample. The parameters measured during experiments were chemical oxygen demand, biogas production, total solid, volatile solids, total Kjeldahl nitrogen and total organic carbon. Rate enhancement of anaerobic digestion and biogas production were occurred for calcium hydroxide digested samples. Therefore calcium hydroxide can be used as an effective alkali for the digestion of organic fraction of municipal solid waste.

Abstract

In this work, waste marigold flowers from Temple were used as adsorbent to remove cadmium (II) and chromium (VI) ions from aqueous solutions. Influences of initial heavy metal concentrations, contact time, adsorbent dose, temperature and initial pH on removal of cadmium (II) and chromium (VI) ions were studied under batch mode of operation. Both the adsorption process of cadmium (II) and chromium (VI) followed pseudo-second order kinetics. Adsorption isotherm parameters of cadmium (II) and chromium (VI) on dried marigold flower were determined using Langmuir and Freundlich models. Thermodynamic parameters depicted that the process was spontaneous and exothermic under experimental conditions. The maximum removal efficiency of cadmium (II) was obtained as 83% at contact time 75 min and pH 5. The maximum removal efficiency of chromium (VI) was found as 96% at contact time 105 min and pH 3. Dried marigold flower showed active reusability characteristics upto three consecutive adsorption-desorption cycles.

Abstract

The optimum inclination and orientation of fixed Photovoltaic (PV) panels has long been defined in terms of maximizing the annual electricity yield per capacity installed according to the hemisphere and latitude where the PV system is located. Such optimum setup would thus also maximize the output per system cost, but it would not maximize the output per unit of available area, and it would not necessarily optimize the contribution of photovoltaic electricity vis-a-vis overall electricity demand patterns. This study seeks to draw the attention of policy-makers to the fact that incentivizing lower-than-optimum PV panel tilt angles can be an inexpensive strategy to substantially increase the renewable electricity yield in a given area. It also discusses how such strategy can be incorporated into an overall supply/demand grid management and renewable energy integration plan.