Stream Energy Research Articles

Mobile app «My energy stream» as a digital receptive music therapy technology of neurotic stress related disorders

Mobile app «My energy stream» as a digital receptive music therapy technology of neurotic stress related disorders

On the Modelling of Marine Current Turbine Power Curves

On the Modelling of Marine Current Turbine Power Curves

Purple Perilla by Can Xue

Reviewed by: Purple Perilla by Can Xue Siyu Cao Can Xue Purple Perilla Trans. Karen Gernant & Chen Zeping. New York. Common Era. 2020. 148 pages. CAN XUE’S Purple Perilla includes three short stories that immerse readers in a world where reality and absurdity collide. In “An Affair,” the peaceful yet bland life of a primary school teacher in her midthirties [End Page 65] is suddenly disrupted by an anonymous love letter, and her ensuing adventure turns out to be both physical and spiritual. While the teenage boy in “Mountain Ants” is entrusted by an old beggar to retrieve and safeguard a lost world where humans and ants can live together, the kid in “Purple Perilla,” the title story, encounters five wolves in hallucinations and decides to live in the hills permanently. With Can Xue’s concise, energetic narrative, and the excellent translation by Karen Gernant and Chen Zeping, these stories, in spite of their totally different settings and plots, constitute a relay of spiritual rebellions allowing all the protagonists to reconsider the meaning of life and the possibility of self-redemption. For many commentators, it is almost irresistible to compare the style of Can Xue’s fiction with the works of Franz Kafka and Italo Calvino. In this collection of short stories, readers can still identify some fundamental themes recurring in modern-ist literatures: alienation, the separation between nature and the civilized world, and the lingering confusion about the meaning of existence. A revisit to these ahistorical, universalist questions in the (post)pandemic era seems timely, for Can Xue adds a touch of idealistic optimism to her characters’ seemingly irrational adventure. The sense of absurdity oozing from all the stories does not imply a total surrender to loneliness and meaninglessness. On the contrary, a quiet stream of energy to undertake “little revolutions” in everyday life, though presented in a self-restrained tone, can be clearly detected in all three protagonists’ internal monologues. Can Xue’s works are well known for their obscurity, and this Isolarii collection is no exception. While the language is simple and straightforward, its multilayered narrative structure poses a challenge to prospective readers. As a work of translation, elements of Chinese tradition and mythology occasionally pop up in its settings and plots but prove to be no cultural obstacle for international readers to empathize with the characters throughout their adventures. Still, readers may benefit from rereadings of the texts, for these stories, in a sense, can be seen as a literary experiment. After witnessing the characters’ “accidental” involvement in the confrontation between human and nature, readers are encouraged to ask themselves: after absorption into an endless monotonousness and loneliness, is it still possible for them to invoke the impulsion to break away, even just temporarily, from the repetition of sameness in daily life? Siyu Cao Shanghai International Studies University Copyright © 2022 World Literature Today and the Board of Regents of the University of Oklahoma

Renewable Energy and Its Implications in the African Context

The environmental implications of energy systems in developing countries have significant impacts on the daily and long-term life quality of the population. These implications include mitigating impacts of climate change, deforestation, improving food security and the multidimensional energy security concerns. Increasing accessibility of reliable and cost-effective renewable energy streams, creating sustainable and profitable businesses that improve living standards and create economic opportunities, which co-create social and environmental values are necessary and essential markers for transitions towards a flourishing society. Energy is essential to sustain modern life. Here, security implies the economic, social, and environmental impacts of energy on the wellbeing of a society. The energy regime that a country chooses has wider implications on its national security strategy and foreign relations. It affects the economic and technological pathways it takes and impinges on overall developments, which include industry, education, environment, and the way of life. Selecting the optimal innovation strategy that includes appropriate renewable energy technologies which meet the needs and harness the available energy resources is one of the primary variables that impact the performance renewable energy projects. Cost, reliability, maintenance, and cultural orientation need to be considered for innovation & technology selection. In the African context, our research indicates addressing the environmental implications of energy systems necessitates whole system wide change that is underpinned by transitions from utilizing conventional energy sources to renewable energy streams. Furthermore, it requires re-configuration of research & development to applied research, re-constitution & focus on incubating enterprises & entrepreneurs, re-configuration of education from abstract education to education that enables solutions development to address local challenges, development in the energy & other sectors to address climate change, health impacts, job creation, energy & food security in concert with developing synergistic and symbiotic shared vision and paradigm shift towards a flourishing future. Our research findings inform us that the meaning and application of energy affordability has a significant difference from what is in the current literature. Energy affordability is defined as the financial capability of a household to pay for basic energy services. In other words, it could be expressed as the monthly energy expenditure of a household divided by its monthly income. Expenditure substitution, digital/electronic payments for energy services, which are configured as “pay-as-you-go” have changed the affordability landscape. While affordability is an important factor, its meaning and application is more nuanced from what is reported in extant literatures.

Gas Dynamic Air Distribution for Post-Reaction Gas Afterburning in a Metallurgical Furnace

In the paper, the course of post-reaction gas afterburning generated during the metallurgical process where the reduction of metal and semi-metal oxides is performed with the use of carbon is presented. Process waste gases can be an alternative source of energy to be used in the same process or converted to another. The participation of chemical enthalpy in the total energy stream of the post-reaction gas is 93 %, the rest is physical enthalpy. In the study, particular attention was paid to the proper mixing of fuel and oxidizer and to maintaining an appropriate ratio of excess combustion air λa. The dynamics of the post-reaction gas combustion processes was calculated according to several popular models but the best results were obtained using the two-step mechanism with reaction constants according to Westbrook-Dryer.

Flood Hazard Modelling in Upper Mandakini Basin of Uttarakhand

Floods in Himalayan region raise serious concerns regarding ongoing path of development as recent manifestations of catastrophic events establish link between climate changes and risk to anthropogenic activities in mountainous regions. Scientists predict frequent occurrence of such disasters wherein rapid glacial melting; incidents of glacial lake outburst and weather extremes may trigger floods in the Himalayan mountains. This paper examined flood risk in Upper Mandakini basin through GIS based flood simulationto highlight flood potential and risk associated with such hazard in the study area.It is observed that floods in study area display hazardous interplay of natural terrain gradient, high kinetic energy of streams, and intense rainfall. The upper sections of basin that includes Kali Ganga, Mandani Ganga, Madhyamaheshwar and Mandakini rivers shows high flood susceptibility with greatest risk in the latter. Such hazardousness is likely to be intensified by ongoing anthropogenic activities in the basin.

Proposal and analysis of a poly-generation process for coal gasification and ironmaking

The novel gasification-reduction coupling process (GRCP) was proposed to obtain higher coal gas/hot metal poly-generation system efficiency. The hematite particles replaced previous moderators (H2O/CO2) in the entrained-flow gasifiers, and direct reduced iron (DRI) can be obtained simultaneously. In this study, the thermodynamic model was established to predicate material streams in GRCP. Numerous cases with different material ratios were also examined to investigate the relevant effects, such as effective gas ratio ([CO] + [H2]), metallization ratio (Fe wt.%), and reduction degree (R). To further quantify energy streams, the exergetic analysis was also conducted according to different definitions. The results indicated that both chemical and physical exergy of high temperature reducing gas transferred into DRIs through the coupling process. Therefore, a significant decrease was observed in cold gas efficiency (72.7%). The exergetic evaluation also shows that GRCP still kept a high-level (83.6%) based on all substances. Since the chemical exergy of DRI was stable exergy storage during the subsequent utilization, higher system efficiency can be expected in the further development of GRCP.

Mapping a blue energy future for British Columbia: Creating a holistic framework for tidal stream energy development in remote coastal communities

This study develops and implements an interdisciplinary framework to provide a holistic examination of the potential for tidal stream turbines (TST) to displace diesel generated electricity in remote coastal First Nations communities in British Columbia. In doing so it seeks to answer the following research questions: what is the distribution of practical tidal resources in the study region, for which communities is tidal energy a potentially viable electricity source, and what are the benefits and challenges of TST development. GIS Multi-Criteria Decision Analysis and interviews with high level marine spatial planning decision makers are used to identify practical resource sites, bridge knowledge gaps, assess views towards TST development, and understand the desired characteristics of community energy systems. Additional techno-economic criteria for tidal site identification are included to identify communities that may be candidates for TST integration. Results illustrate the need for information provision to communities from resource quantification to characteristics of renewable energy technologies; self sufficiency as being the primary electrification driver; and funding/human resource capacity as being substantial barriers to development. Approximately 89.8 km2 of practical tidal resource is identified, with ≈21.9 km2 of techno-economically feasible practical resource in proximity to nine communities. Four communities appear to be promising candidates for tidal development, and overall results indicate significant interest within the study region for TST development. The interdisciplinary framework presented here provides a methodology that can be adapted and implemented in other jurisdictions to identify practical resources and incorporate social dimensions into MRE decision making.

Determining the Level of Security Culture of the Entity Using the Midified Shalom Schwartz Value Model

Each consciously existing entity has its own unique, hierarchical set of values, helping to make decisions and set directions for action. This power is a security culture, also defined as a set of universal values, attitudes and beliefs. The foundation upon which the security culture grows is the three pillars of security – the three energy streams of the security culture. The objective is to estimate the level of the entity’s security culture and present its structure. The determination of the empirical size of a security culture is made by adapting Shalom Schwartz’s value theory and his ten types of fundamental values. The values placed on the Schwartz circle model are aggregated to the appropriate energy streams of the security culture, and this move allows for empirical determination of the level of the security culture of an individual. The obtained results show the structure of energy streams and determine the empirical level of the subject’s security culture. The approach taken shows that the level of security culture is computable.

Tidal stream energy potential in the Shannon Estuary

The tidal and river in-stream energy resource in the Shannon Estuary (W Ireland) is investigated using of high-resolution numerical modelling and spatial analysis. Although freshwater discharges are large, their influence on the available resource is found to be all but negligible, the tide being the main driver of estuarine circulation. The Tidal Stream Exploitability (TSE) index is adapted to the analysis of estuaries with non-depth-limited areas (TSEndl), such as the Shannon Estuary, and then used to select the hotspots with potential for a tidal stream farm. For this purpose, a new depth penalty-limiting function is defined to avoid overestimating the available energy potential in areas with depths greater than those required for tidal energy converter operation. Seven hotspots are identified based on the revised index. The approach followed in this study illustrates the applicability of high-resolution numerical modelling and spatial analysis for identifying the most appropriate areas for tidal stream energy conversion. Finally, the potential of tidal stream energy to contribute to the much-needed decarbonisation of the energy mix in Ireland is emphasized.

Thermal Fluxes and Solar Energy Storage in a Massive Brick Wall in Natural Conditions

The thermal state of building elements is a combination of steady and transient states. Changes in temperature and energy streams in the wall of the building in the transient state are particularly intense in its outer layer. The factors causing them are solar radiation, ambient temperature and long-wave radiation. Due to the greater variability of these factors during the summer, the importance of the transient state increases at this time. The study analysed heat transfer in three aspects, temperatures in the outer, middle and inner parts of the wall, heat fluxes between these layers and absorption of solar energy, heat transfer coefficient on the wall exterior was also calculated. The analysis is based on temperature measurements at several depths in the wall and measurements of solar radiation. The subject of research is a solid brick wall. The results show that the characteristics of heat flow in winter and summer for the local climate show distinct differences. In the winter, the maximum temperature difference between the external and internal surface of the wall was 10 °C and in summer, 20 °C. In the winter, the negative flux on the internal surface reached 10 W/m2 and on the external 40 W/m2 and was constant throughout the day. The mean heat transfer coefficient on the exterior surface for winter week was 8 W/(mK). A Nusselt and Biot number for dimensionless convection analysis was calculated. The research contributes to the calculation of the variability of heat or cold demand in a daily period and to learn about the processes of energy storage in the wall using sensible heat.

Optimal design of a hybrid thermal- and membrane-based desalination unit based on renewable geothermal energy

• A renewable-based hybrid desalination system consisting of HDH and RO is evaluated. • Two different operating modes of the introduced system are investigated. • Exergoeconomics is used to identify the optimal working condition of the system. • Maximum exergy efficiency of the plant is 28.86% for the second operating mode. • The first operating mode can provide freshwater at a maximum rate of 22070 m 3 /day. In this article, exergoeconomic analysis of a hybrid desalination system driven by renewable geothermal energy source is investigated. Freshwater and electrical power are the products of this system. Humidification – dehumidification (HDH) unit works in parallel with reverse osmosis (RO) unit to produce freshwater and Kalina cycle is the power generator unit. Thermoelectric generator (TEG) is responsible for providing the energy required by RO unit. As both HDH and TEG can operate with low-grade energy, two different modes are suggested for the proposed system. In the first mode, the geothermal low grade energy stream is passed to TEG unit, while in the second, it goes through the HDH unit. The effect of different parameters on four main objective functions is examined in parametric study. Moreover, with the aid of selection maps, the objectives of modes can be compared in different operating conditions. The maximum attainable exergy efficiency is calculated to be 28.86% for mode 2. Single objective optimization studies revealed that the first mode produces the largest amount of freshwater at a rate of 22,072 (m 3 /day), while the minimum achievable freshwater cost and total product cost rate can be obtained in the second mode, which is calculated to be 21.94 (¢/m3) and 37.19 ($/GJ). Besides, Sankey diagrams for exergy flow and mass flow of saline water are presented to unravel the impact of each sub-system on exergy and salinity.

Changes in stream power and morphological adjustments at the event-scale and high spatial resolution along an ephemeral gravel-bed channel

Sediment budgets and morphological channel adjustments are closely related to changes in stream power. In ephemeral channels, whose geomorphic response depends on the magnitude and frequency of hydrological events isolated in time, such relationships are often difficult to establish. This study sought to quantitatively relate morphological adjustments to stream power along different reference channel reaches for the period 2018–2020 in the Azohía Rambla, a Mediterranean gravel-bed ephemeral stream in southeastern Spain. Very high resolution digital terrain models (VHR DTM) (at 1 to 2.5 cm pixel size), combined with ortophotographs and 3D point clouds, generated via SfM photogrammetry and terrestrial laser scanning (TLS) for pre- and post-event stages, together with ground-based surveys were used to estimate the spatial variability of morphological sediment budgets and to assess channel bed mobility and changes in net sediment flux during the study period in two spatial scenarios: reference channel reaches (RCRs) and pilot bed survey areas (PBSAs). The hydraulic variables (flow velocity, Froude number, shear stress, mean stream power and energy gradient, among other) were estimated using a 1D hydrodynamic model calibrated with field information. The high resolution maps allowed a spatially-explicit analysis of stream power and transport efficiency in accordance with the areas of erosion and deposition in each RCR. The incision and bed armoring processes showed different trends according to the stream power (ω), cumulative excess energy (εc), and relative bed stability (RBS). The greatest morphological adjustments at the event scale coincided with ω values above 300 W m−2, εc higher than 3 MJ, and RBS below 0.5. The relationships between the mean stream power gradient at peak flood discharges and the changes in bed elevation verified the bed aggradation (an average surface raising of 0.17 to 0.22 m for δω/δs of −6.2 to −14.5 W m−2 m−1) during the major flood and bed scour (average surface lowering of 0.16 to 0.19 m for δω/δs of 5.8 to 10.6 W m−2 m−1) in the moderated events at the bankfull and sub-bankfull stages. Furthermore, this study contributes new relevant data to the scarce existing literature on the relationships between stream power and morphosedimentary adjustments in a fluvial system highly sensitive and resilient to climate change, as is the case of ephemeral gravel-bed channels.

Runoff generation from a combined glacier and páramo catchment within the Antisana Reserve in Ecuador

Runoff processes in glacier and páramo catchments in the Andean region are of interest as they are vitally important to serve the water needs of surrounding communities. Particularly in Northern Ecuador, the runoff processes are less well-known due to the high variability of precipitation, young volcanic ash soil properties, soil moisture dynamics and other local factors. Previous studies have shown that the melting of glaciers contributes to runoff generation and that the páramo ecosystem plays an important role in regulating runoff during periods of low precipitation. Data collection and experimental investigations were carried out in a catchment of 15.2 km2 and altitude ranging between 4000 and 5700 m above sea level. Environmental tracers and hydrochemical catchment characterization were used for identifying runoff sources and their respective contributions during dry and wet conditions. Dry conditions are defined as periods where precipitation was absent for at least three consecutive days and wet conditions imply rainfall events. This study highlights the importance of the páramo on contributing to total runoff during baseflow (70% of total runoff) and the capacity of the páramo to dissipate the stream energy and buffer the peak flow during rainfall conditions. Electrical conductivity together with stable isotopes were identified as conservative tracers that characterize the end-member concentrations.

Dynamic performance enhancement of solar-aided coal-fired power plant by control strategy optimization with solar/coal-to-power conversion characteristics

A solar-aided coal-fired power plant (SACFPP) facilitates the investment reduction and efficiency enhancement of concentrated solar power, having multiple input energy streams. The intermittent nature of solar energy requires new control strategies for SACFPP to generate controllable power. A revised control strategy considering solar/coal-to-power conversion characteristics is proposed, where the influences of solar irradiance changes are decomposed into the changes in live-steam working capacity and boiler heat absorption. Within the proposed control strategy, models to explicitly calculate the set points of coal consumption and feedwater mass flowrate are developed. The operational enhancement is evaluated with a 660 MW SACFPP where the trough collector system works in parallel with the second and third high-pressure heaters. The control effects on stability and energy conversion are analyzed under solar irradiance disturbances and actual conditions. Results show that the revised control strategy promotes the quick and smooth power stabilization. The settle time decreases from 1663 s to 701 s when solar irradiance step decreases from 700 W m−2 to 500 W m−2. Under actual conditions, the power ratio deviation reduces by 63.16% with the proposed strategy compared with the original strategy. The solar-to-electricity efficiency fluctuations are slightly reduced.

Energy management and control optimization of marine current power system based on hybrid energy storage system

Due to climate change and the risk of depletion of traditional fossil energy, developing renewable energy has become a common consensus of the international community. Marine current energy is regarded as the most desirable form of ocean energy due to its high density and strong predictability. However, the variations of marine current velocity caused by the swell effect lead to the fluctuation of marine current power. In this paper, an energy management strategy based on a Two-Stage Fuzzy Logical Controller (TSFLC) is proposed to redistribute the marine current power and abate marine current power fluctuation. The hybrid energy storage system composed of vanadium redox flow battery and supercapacitor banks (SCB) is applied to smooth the marine current power and improve the power quality according to the energy management strategy. Meanwhile, TSFLC can reduce the rated capacity of SCB, avoid the overcharge and over-discharge of the SCB, and keep the state of charge of SCB within a reasonable range. Furthermore, for better tracking performance and smaller steady-state error, particle swarm optimization is applied to tune the parameters of the PI controller in the SCB control loop. A simulation model of a 3-MW marine current power system is built to verify the effectiveness of the control strategy.

A review of tidal energy—Resource, feedbacks, and environmental interactions

The ocean contains a variety of renewable energy resources, little of which has been exploited. Here, we review both tidal range and tidal stream energy, with a focus on the resource, feedbacks, and environmental interactions. The review covers a wide range of timescales of relevance to tidal energy, from fortnightly (spring-neap) and semi-diurnal variability, down to array, and device-scale turbulence. When simulating the regional tidal energy resource, and to assess environmental impacts, it is necessary to account for feedbacks between the tidal array and the resource itself. We critically review various methods for simulating energy extraction, from insights gained through theoretical studies of “tidal fences” in idealized channels, to realistic three-dimensional model studies with complex geometry and arrays of turbines represented by momentum sinks and additional turbulence due to the presence of rotors and support structures. We discuss how variability can be reduced by developing multiple (aggregated) sites with a consideration of the enhanced phase diversity offered by exploiting less energetic tidal currents. This leads to future research questions that have not yet been explored in depth at first-generation tidal sites in relatively sheltered channels (e.g., the interaction of waves with currents). Such enhanced understanding of real sea conditions, including the effects of wind and waves, leads to our other identified primary future research direction—reduced uncertainties in turbulence predictions, including the development of realistic models that simulate the interaction between ambient turbulence and the turbulence resulting from multiple wakes, and changes to system-wide hydrodynamics, water quality, and sedimentation.

A review of the UK and British Channel Islands practical tidal stream energy resource.

This review provides a critical, multi-faceted assessment of the practical contribution tidal stream energy can make to the UK and British Channel Islands future energy mix. Evidence is presented that broadly supports the latest national-scale practical resource estimate, of 34 TWh/year, equivalent to 11% of the UK’s current annual electricity demand. The size of the practical resource depends in part on the economic competitiveness of projects. In the UK, 124 MW of prospective tidal stream capacity is currently eligible to bid for subsidy support (MeyGen 1C, 80 MW; PTEC, 30 MW; and Morlais, 14 MW). It is estimated that the installation of this 124 MW would serve to drive down the levelized cost of energy (LCoE), through learning, from its current level of around to below , based on a mid-range technology learning rate of 17%. Doing so would make tidal stream cost competitive with technologies such as combined cycle gas turbines, biomass and anaerobic digestion. Installing this 124 MW by 2031 would put tidal stream on a trajectory to install the estimated 11.5 GW needed to generate 34 TWh/year by 2050. The cyclic, predictable nature of tidal stream power shows potential to provide additional, whole-system cost benefits. These include reductions in balancing expenditure that are not considered in conventional LCoE estimates. The practical resource is also dependent on environmental constraints. To date, no collisions between animals and turbines have been detected, and only small changes in habitat have been measured. The impacts of large arrays on stratification and predator–prey interaction are projected to be an order of magnitude less than those from climate change, highlighting opportunities for risk retirement. Ongoing field measurements will be important as arrays scale up, given the uncertainty in some environmental and ecological impact models. Based on the findings presented in this review, we recommend that an updated national-scale practical resource study is undertaken that implements high-fidelity, site-specific modelling, with improved model validation from the wide range of field measurements that are now available from the major sites. Quantifying the sensitivity of the practical resource to constraints will be important to establish opportunities for constraint retirement. Quantification of whole-system benefits is necessary to fully understand the value of tidal stream in the energy system.

Sea level rise changes estuarine tidal stream energy

Worldwide, many estuaries have the potential to harness tidal stream energy via the conversion of current velocities into a consumable energy source. However, the effects of future sea level rise on the tidal stream energy resource within different estuary types are largely unknown. To address this knowledge gap, 978 idealised hydrodynamic simulations were carried out to first identify estuary types and the location of hotspots within them that are promising for tidal energy exploitation in present-day conditions, and then provide insights into the altered tidal stream energy of different estuary types under various future sea level rise and river inflow scenarios. The results indicate that, under sea level rise, the tidal stream energy of prismatic estuaries reduces more than that of converging estuaries. This implies that estuaries that are currently worth exploiting for tidal power may cease to be in the future due to accelerating sea level rise. Further, as sea level rise may bring about geomorphic adjustments, the spatial energy patterns within an estuary may shift and optimal energy sites may be eliminated or displaced. These climate change effects pose a serious challenge for the management of tidal energy generation in future. In this context, the findings of this study are of practical significance for decision-makers in designing long-term strategies for the development of tidal energy installations in estuaries under rising mean sea levels.

Sizing strategies of photovoltaic systems in nZEB schemes to maximize the self-consumption share

The integration of renewable energy systems in buildings has become a common practice. The design of net Zero Energy Buildings promotes the energy transition from fossil fuels based technologies by coupling renewable systems as photovoltaic (PV) plants with heat pumps for heating and cooling. In this framework, the correct sizing of PV plants plays a central role in the perspective of the definition of self-consumption schemes. Considering the problems related to small-scale photovoltaic plants, the present paper proposes an analysis of different sizing strategies on the energy streams between the building and the electrical grid to reduce the bidirectional energy flows with the electrical grid. The design objective concern the minimization of both the energy exported and imported through an optimized size of the PV plant and the integration of electrochemical energy storage. The investigation is based on the experimental data under real operating conditions obtained from two different residential buildings, a conventional residential house, and a nearly Zero Energy Building (nZEB). The paper aims to discuss the results of the monitoring activity and define criteria and guidelines for the design of this kind of systems based on real collected data. The use of two different self-consumption indexes helps to determine how close the system is to a zero-energy configuration showing that the use of a small to medium size storage system is fundamental for maximizing the self-consumption share of the energy produced.