This paper assesses wind resource characteristics and energy yield for micro wind turbines integrated on noise barriers. An experimental set-up with sonic anemometers placed on top of the barrier in ...reference positions is realized. The effect on wind speed magnitude, inflow angle and turbulence intensity is analysed. The annual energy yield of a micro wind turbine is estimated and compared using data from a micro-wind turbine wind tunnel experiment and field data. Electrical energy costs are discussed as well as structural integration cost reduction and the potential energy yield could decrease costs. It was found that instantaneous wind direction towards the barrier and the height of observation play an influential role for the results. Wind speed increases in perpendicular flows while decreases in parallel flow, by +35% down to −20% from the reference. The azimuth of the noise barrier expressed in wind field rotation angles was found to be influential resulted in 50%–130% changes with respect to annual energy yield. A micro wind turbine (0.375 kW) would produce between 100 and 600 kWh annually. Finally, cost analysis with cost reductions due to integration and the energy yield changes due to the barrier, show a LCOE reduction at 60%–90% of the reference value.
•Sonic anemometer measurement campaign on top of a noise barrier (windscreen).•1st attempt to quantify the energy yield of micro wind turbines atop noise barriers.•Wind speed above barrier increases for perpendicular and decreases for parallel flow.•Noise barriers can change the yield of a micro wind turbine by 50%–130%.•Electricity cost can drop due to increased yield and reduced cost from integration.
Centimeter-scale micro wind turbines have been proposed to power small devices. Design models and operating conditions for large scale wind turbines do not directly apply towards these small ...harvesters. We perform an experimental investigation of a swirl-type micro-wind turbine. We measure the useful power extracted from this turbine in an open circuit suction type wind tunnel facility. The optimal resistive loads for different flow speeds are determined. A model for the friction, torque drive and generated power is derived and validated. The effect of varying the direction of incident flow on the turbine performance is also determined. The results show an optimal combination between the rotor diameter and the number of rotor revolutions. The power density and efficiency of this turbine were found to be larger than previously tested turbines that have slightly larger diameters. This is true over a broad range of free stream speeds. Finally, because of its shape, the swirl configuration is effective in harvesting power for yaw angles of ±30°.
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•We test the performance of a swirl type micro-wind turbine.•We provide a model for output power prediction of CSMWTs.•We achieved high power density for swirl CSMWTs.•No reduction in generated power for yaw angles less than 10°.
Micro wind turbines can be structurally integrated on top of the solid base of noise barriers near highways. A number of performance factors were assessed with holistic experiments in wind tunnel and ...in the field. The wind turbines underperformed when exposed in yawed flow conditions. The theoretical cosθ theories for yaw misalignment did not always predict power correctly. Inverter losses turned out to be crucial especially in standby mode. Combination of standby losses with yawed flow losses and low wind speed regime may even result in a net power consuming turbine. The micro wind turbine control system for maintaining optimal power production underperformed in the field when comparing tip speed ratios and performance coefficients with the values recorded in the wind tunnel. The turbine was idling between 20%–30% of time as it was assessed for sites with annual average wind speeds of three to five meters per second without any power production. Finally, the field test analysis showed that inadequate yaw response could potentially lead to 18% of the losses, the inverter related losses to 8%, and control related losses to 33%. The totalized loss led to a 48% efficiency drop when compared with the ideal power production measured before the inverter. Micro wind turbine’s performance has room for optimization for application in turbulent wind conditions on top of noise barriers.
Wind energy conversion systems (WECS) have gained increasing attention in recent years as promising renewable energy sources. Despite their potential, a clear research gap exists: the majority of ...WECS underperform in low wind speed conditions, limiting their applicability in many regions. To address this problem, this study proposes a novel approach by developing a 100 W micro wind turbine using Polylactic Acid (PLA) to generate efficient power in low wind speed conditions. The proposed wind turbine design employs Blade Element Momentum Theory (BEMT), which is commonly used for modeling wind turbine performance. Geometric design, mechanical analysis, and aerodynamic analysis are the fundamental considerations for designing any machine. In this work, the CREO 3.0 three-dimensional modeling software is used to create the geometric design of the proposed work. The airfoil SD7080 is selected due to its superior aerodynamic performance, and mechanical properties such as Young's modulus, density, and Poisson's ratio are attained to evaluate the wind blade's performance. Additionally, ANSYS 15.0 is used to conduct a detailed analysis of the proposed wind turbine, evaluating properties such as equivalent stress, deformation, and equivalent strain. Both simulation (ANSYS 15.0) and experimental setups are used to investigate the proposed wind turbine's performance, and the corresponding results are presented and discussed in this manuscript. The results indicate a significant performance improvement of the proposed wind blade when compared to conventional and ABS wind blades, demonstrating its potential as a more efficient solution for WECS. This proposed wind turbine design overcomes the problems like underprformance in low wind speed conditions and the wind turbine efficiency in all regions.
National targets for increased renewable energy are common-place internationally and small/micro-generation may help achieve such goals. Energy yields from such technologies however, are very ...location and site specific. In rural environments, the average wind speed is relatively high and the homogeneous landscape promotes laminar air flow and stable (relatively) wind direction. In urban environments however, the wind resource has lower mean wind speeds and increased levels of atmospheric turbulence due to heterogeneous surface forms. This paper discusses the associated costs per unit of electricity generated by micro wind energy conversion systems from the perspective of both urban and rural locations, with three case studies that consider the potential and financial viability for such systems. The case studies ascertain the cost of energy associated with a standard HAWT (horizontal axis wind turbine), in terms of exemplar rural and urban locations. Sri Lanka, Ireland and the UK, are prioritised as countries that have progressive, conservative and ambitious goals respectively towards the integration of micro-generation. LCOE (Levelized cost of energy) analyses in this regard, offers a contextualised viability assessment that is applicable in decision making relating to economic incentive application or in the determination of suitable feed-in tariff rates.
•Levelized cost of energy analysis of rural/urban wind energy systems is presented.•Progressive, conservative and ambitious wind energy case studies are compared.•Design of Experiments analysis (DOE) considers LCOE parameter intra-dependencies.•Urban wind energy harvesting for each case proved to be a cost preclusive option.
•Three micro-turbines with output power less than 1kW were designed for operation in low wind speed regions.•In addition to the output power, starting time was considered as a key parameter during ...the design.•The effects of generator resistive torque and number of blades on the performance of the turbines were investigated.
Utilizing the micro scales of wind turbines could noticeably supply the demand for the electricity in low wind speed regions. Aerodynamic design and optimization of the blade, as a main part of a wind turbine, were addressed in the study. Three micro scales of horizontal axis wind turbines with output power of 0.5, 0.75 and 1kW were considered and the geometric optimization of the blades in terms of the two involved parameters, chord and twist, was undertaken. In order to improve the performance of the turbines at low wind speeds, starting time was included in an objective function in addition to the output power – the main and desirable goal of the wind turbine blade design. A purpose-built genetic algorithm was employed to maximize both the output power and the starting performance which were calculated by the blade-element momentum theory. The results emphasize that the larger values of the chord and twist at the root part of the blades are indispensable for the better performance when the wind speed is low. However, the noticeable value of the generator resistive torque could largely delay the starting of the micro-turbines especially for the considered smaller size, 0.5kW, where the starting aerodynamic torque could not overcome the generator resistive torque. For that size, an increase in the number of blades improved both the starting performance and also output power.
This study gives a thorough analysis on the wind energy potential in Dhaka, Bangladesh, utilizing data from NASA Power's remote sensing tools and weather data from the Bangladesh Meteorological ...Department (BMD). The wind speed data collected over a 22 year period at an altitude of 10 m. The results indicate that 3.07 m per second (ms
−1
) is Dhaka city's typical wind speed, while the maximum wind speeds were recorded in June and July. A Weibull distribution is used to observe the wind data, as well as to calculate the Weibull form parameter of 2.65 and the scale parameter of 3.43 ms
−1
. Based on these parameters, the most probable wind speed along with the wind speed carrying maximum energy were calculated 2.83 ms
−1
and 4.28 ms
−1
, respectively. The highest density of energy has been found in the month of July with a value of 52.11 W/m
2
. According to the study, the south is the most prominent wind direction for Dhaka city. Moreover, the study analyzes the relations between energy density and other variables, like wind speed, humidity, dry bulb temperature, etc. Positive correlations between energy density, wind speed, and dry bulb temperature imply that the higher wind speeds and dry bulb temperatures result in greater energies. The study's conclusions offer intuitive information about Dhaka City's potential for wind energy and can support direct future efforts to pursue this green resource in alignment with the Sustainable Development Goals (SDGs) of Bangladesh.
This paper evaluates the life cycle environmental sustainability of micro-wind turbines in the UK in comparison with grid electricity and solar PV (photovoltaics). The results suggests that per kWh ...electricity generated, the majority of environmental impacts from the wind turbines are lower than from grid electricity, ranging from 26% lower terrestrial toxicity to 92% lower global warming. However, depletion of abiotic elements, fresh-water and human toxicities are 82%, 74% and 53% higher than for grid electricity, respectively. The wind turbines are more environmentally sustainable than solar PV for seven out of 11 impacts, ranging from 7.5% lower eutrophication to 85% lower ozone layer depletion. However, depletion of fossil resources, fresh-water, human and terrestrial toxicities are higher for the wind turbine than for the PV, ranging from 5% for the former to 87% for the latter. UK-wide deployment of micro-wind turbines would save between 0.6 and 1% of GHG (greenhouse gas) emissions on 2009 levels. Therefore, the potential of micro-wind turbines to contribute towards UK's climate change targets is limited.
•Life cycle environmental impacts of micro-wind turbines estimated for UK conditions.•The majority impacts are lower for micro-wind turbines than for grid electricity and solar PV.•Some impacts from micro-wind are higher, notably fresh-water and human toxicity.•At the national level, wind turbines would save only 0.6% GHG emissions on 2009 levels.•The potential of micro-wind turbines to contribute to UK's climate change targets is limited.
•This paper presents an energy and environmental analysis of a small hybrid system.•It includes photovoltaic (PV) and a micro wind turbine (MWT).•Micro wind turbine and PV array tested individually ...and as hybrid system.
This paper presents a preliminary energy and environmental analysis of a vertical-axis micro wind turbine with a nominal electric power of 3.7kW. This prototype is called AM300.
The main aim of the paper is to assess the amount of electric energy production of the AM300 and its feasible use in low wind speed areas. Furthermore, analyzing its low environmental impact, a potential installation in a natural protected area was considered.
The turbine power curve was estimated by anemometric measurements. Furthermore, foreseeable prototype hybridization with PV array was analyzed.
The environmental performance was assessed evaluating the soil, hydro geological, biodiversity and noise impacts. Finally, an analysis of the CO2 emissions avoided is reported. The obtained results show good sustainability perspectives.
► Net-zero exergy targets are put forth for more energy-sufficient buildings and districts. ► A premier building that is the first LEED Platinum building in Turkey exemplifies this target. ► The ...building integrates low-exergy measures with PV/BIPV, CHP, GSHP, solar collectors and TES. ► Two districts in the south heating network of Stockholm are compared with this technology bundle. ► Net-zero exergy targets are related to a re-structuring of an exergy-aware energy value chain.
Based on two case studies, this paper explores the nexus of exergy, net-zero targets, and sustainable cities as a means of analyzing the role of exergy-aware strategies at the building and district level. The first case study is a premier building in Ankara that is ready to meet the net-zero exergy target. It is also the first building in Turkey to receive the highest Platinum rating in Leadership in Energy and Environmental Design. A net-zero exergy building (NZEXB) is a building that has an annual sum of net-zero exergy transfer across the building-district boundary. This new target is made possible by lowered annual exergy consumption, (AEXC), and increased on-site production from a bundle of sustainable energy technologies. The modeled results of the building indicate that the reduced AEXC of 60kWh/m2yr is met with on-site production of 62kWh/m2yr. On-site production includes PV and building integrated PV, a micro-wind turbine, combined heat and power, GSHP, and solar collectors. Diversified thermal energy storage tanks further facilitate the exergy supply to meet with the exergy demand. The results of this case study provide key lessons to structure an energy value chain that is more aware of exergy, which are up-scalable to the district level when the bundle of sustainable energy technologies is zoomed out across a larger spatial area. These key lessons are then compared with the second case study of two districts in the south heating network of the city of Stockholm, which was the European Green Capital in 2010. The levels of exergy match in these districts of Stockholm, namely the districts of Högdalen and Hammarby, is found to be 0.82 and 0.84, respectively. However, there remain several bottlenecks for these districts to reach net-zero targets at the community level. The paper concludes that the NZEXB case study has much to offer as a “building block” to reform the way energy is converted and managed and in this way, to structure an exergy-aware energy value chain for greater sustainability in green cities of the future.
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