Tidal energy assessment with hydrodynamic modelling

The increasing demand for sustainable energy generation brings a need for tidal current energy resource exploration around the globe. Hydrodynamic modelling is an essential aspect to explore macro tidal sites. In the current research paper, a 2D hydrodynamic model is set up by utilizing the numerical application of Delft3D. The model is validated against the database results and the two macro tidal sites are identified along the coastline of Sarawak, Malaysia. The maximum available kinetic energy flux at the identified location is 0.6 kW/m2, during peak neap tide hours. This stands as a sound justification to have a detailed tidal energy assessment study in this area in future research

Recent Development in the Design of Wind Deflectors for Vertical Axis Wind Turbine: A Review

Developments in the design of wind turbines with augmentation are advancing around the globe with the goal of generating electricity close to the user in built-up areas. This is certain to help lessen the power generation load as well as distribution and transmission network costs by reducing the distance between the user and the power source. The main objectives driving the development and advancement of vertical-axis wind turbines are increasing the power coefficient and the torque coefficient by optimizing the upstream wind striking on the rotor blades. Unlike horizontal-axis wind turbines, vertical axis turbines generate not only positive torque but also negative torque during operation. The negative torque generated by the returning blade is a key issue for vertical-axis wind turbines (VAWTs) that is counterproductive. Installation of wind deflectors for flow augmentation helps to reduce the negative torque generated by the returning blades as well as enhance the positive torque by creating a diversion in the upstream wind towards the forwarding blade during operation. This paper reviews various designs, experiments, and CFD simulations of wind deflectors reported to date. Optimization techniques for VAWTs incorporating wind deflectors are discussed in detail. The main focus of the review was on the installation position and orientation of the deflectors and their potential contribution to increasing the power coefficient. Topics for future study are suggested in the conclusion section of the paper

Micro Vertical Axis Wind Turbine Design Integrated with Wind Accelerating Techniques

Power generation from natural wind is the crucial issue due to rapid depletion of non-renewable energy resources and their pollution demerits. Most observers agreed that long-term economic growth will require technical innovation to make wind energy more competitive with other forms of energy. One among the key trends is the push to improve productivity. Vertical axis wind turbines are capable of extracting power from wind regardless of direction of natural wind flow. Very less work is devoted to improve the characteristics of wind to make it more useable for power generation. Major portion of the research is related to the wind energy system design that caters the domestic needs. A micro vertical axis wind turbine system with integrated wind accelerating techniques is proposed. At the outer of the turbine a wind accelerating convergent duct with larger wind area is proposed, that will perform as a nozzle action to accelerate the natural wind when it strikes on the front half portion of the turbine blades. Proposed micro wind turbine is also integrated with satellite dish type parabolic structure, mounted at the top of the turbine. The parabolic concentrator surface is coated with sun rays reflecting mirrors, sunlight striking on paraboliod surface is directed to words a heat absorbing hollow cylinder, erected at the center of the paraboliod concentrator. Hollow cylinder is the path channel for air leaving the turbine. Air molecules passing through this channel will be heated up, moving rapidly up word creating momentum in air leaving from the turbine. Design of the proposed vertical axis wind turbine system integrated with wind accelerating techniques and experimental study of wind accelerating duct composed of various section is reported in this research work

Micro Vertical Axis Wind Turbine Design Integrated with Wind Accelerating Techniques

Power generation from natural wind is the crucial issue due to rapid depletion of non-renewable energy resources and their pollution demerits. Most observers agreed that long-term economic growth will require technical innovation to make wind energy more competitive with other forms of energy. One among the key trends is the push to improve productivity. Vertical axis wind turbines are capable of extracting power from wind regardless of direction of natural wind flow. Very less work is devoted to improve the characteristics of wind to make it more useable for power generation. Major portion of the research is related to the wind energy system design that caters the domestic needs. A micro vertical axis wind turbine system with integrated wind accelerating techniques is proposed. At the outer of the turbine a wind accelerating convergent duct with larger wind area is proposed, that will perform as a nozzle action to accelerate the natural wind when it strikes on the front half portion of the turbine blades. Proposed micro wind turbine is also integrated with satellite dish type parabolic structure, mounted at the top of the turbine. The parabolic concentrator surface is coated with sun rays reflecting mirrors, sunlight striking on paraboliod surface is directed to words a heat absorbing hollow cylinder, erected at the center of the paraboliod concentrator. Hollow cylinder is the path channel for air leaving the turbine. Air molecules passing through this channel will be heated up, moving rapidly up word creating momentum in air leaving from the turbine. Design of the proposed vertical axis wind turbine system integrated with wind accelerating techniques and experimental study of wind accelerating duct composed of various section is reported in this research work

Effects of Air Supply Terminal Devices on the Performance of Variable Refrigerant Flow Integrated Stratum Ventilation System : An Experimental Study

A variable refrigerant flow integrated stratum ventilation (VRF-SV) system was proposed as an energy efficient substitute for conventional central cooling systems for buildings. The novel system provided conditioned air to enclosed spaces with high indoor air quality and thermal comfort. This study investigated the effects of different types of ASTDs on the performance of the VRF-SV hybrid system. The performance was experimentally evaluated with five air terminal types, including bar grille, double deflection grille, jet slot, perforated and drum louver diffusers. The evaluation was carried out using standard indices: temperature and velocity distribution, airflow pattern, effective draft temperature (EDT), air distribution performance index (ADPI), thermal sensation vote and comfort feedback survey. The results indicated that the ASTD type had a significant impact on airflow pattern. Furthermore, the bar grille diffuser provided the occupants with greater thermal comfort and acceptable indoor environment. Almost all the EDT values determined in the breathing zone in the case with bar grille diffuser found under the satisfactory range, i.e., −1.2 < K < 1.2. Based on these values, the ADPI for bar grille diffuser was calculated as 92.8%. Thus, the bar grille diffuser is recommended to be installed with the VRF-SV hybrid system in buildings.publishedVersionPeer reviewe

Fabrication and Enhanced Performance Evaluation of TiO₂@Zn/Al-LDH for DSSC Application: The Influence of Post-Processing Temperature

A sequence of dye-sensitized solar cells is proposed, utilizing TiO2@Zn/Al-layered double hydroxide (LDH) as their starting materials, in which Ruthenizer N719 was used as a photon absorber. The anticipated system was turned into sheet-like TiO2@mixed metal oxide (MMO) via post-processing treatment. The crystal quality indicated a relation to power conversion efficiency (PCE); this was combined with a comparable morphology profile. In detail, the optimum DSSC device exhibited average sheet-like thickness and a dye loading amount of 43.11 nm and 4.28 ×10−3 mM/cm−2, respectively. Concurrently, a considerable PCE enhancement of the optimum DSSC device (TiO2@MMO-550°) was attained compared to pristine MMO (0.91%), which could be due to boosted electron transfer efficiency. Of the fabricated devices, DSSC fabricated at 550° exhibited the highest PCE (1.91%), with a 35.6% enhancement compared to that obtained at 450°, as a result of its increased open-circuit voltage (3.29 mA/cm2) and short-circuit current (0.81 V). The proposed work delivers an enhanced efficiency as compared to similar geometries

Towards Achieving 100% Renewable Energy Supply for Sustainable Climate Change in Pakistan

Fossil fuel-based energy systems are mostly used for supplying energy that creates negative impacts on the environment, so in this study, the development of a 100% renewable energy system is evaluated for Pakistan for sustainable climate change. This study modeled three scenarios, namely, ongoing (ONG), energy saving policy (ESP), and green energy policy (GEP) scenarios using low emission analysis platform (LEAP) software for the study period 2022 to 2050 for Pakistan. The results revealed that a 100% renewable energy supply could be achieved through the GEP scenario. Model results show that the share of renewable sources in the total energy mix is 1117.08 TWh and non-renewable sources contribute only 18.12 TWh to meet the energy demand of 966.05 TWh until 2050. Non-renewable production leads to the generation of 8.85 million metric tons of carbon emissions, which is too low compared with the 135.47 million metric tons under the ONG scenario. The USD 1482.46 billion investment cost required for adding renewable energy capacity until 2050 is too high as compared with the USD 46.80 billion under the ONG scenario. Energy demand and production requirements are reduced by 34.18% under the ESP scenario until 2050. This approach can also be applicable to the majority of nations worldwide

Subtropical broad-leaved urban forests as the foremost dynamic and complex habitats for a wide range of bird species

Broad-leaved subtropical forests are the most productive, diversified, and complex ecosystems on the planet. Unfortunately, they are currently under severe threat from anthropogenic activities, such as. deforestation, housing settlements, and agricultural expansion. In response to these severe effects, the present study was conducted to explore the current conservation status and population structure of a wide range of bird species inhabiting different subtropical broad-leaved urban forests of Pakistan. In total, 2879 individuals comprising 53 species and 28 families were detected between December 2017 and November 2018 as revealed through the distance sampling line transect method. The habitat selection among bird species varied according to vegetation structure and composition, food resources, adjoining habitats, and human settlements. According to IUCN Red List data, one species was deemed vulnerable out of 53 bird species, while the remaining 52 species were ranked as ofleast concern. The findings of the density analysis revealed that bird density varied between six subtropical broad-leaved forests. Palamar (3.954 ± 0.221 birds/ha) and Kityari (3.138 ± 0.162 birds/ha) were densely populated, whereas Kamal Khan (1.102 ± 0.178 birds/ha) was of the least concern. Likewise, the diversity analysis showed that Kamal Khan was a more diverse habitat (Shannon–Wiener Index; H’ = 3.581 ± 0.021). Shahabad was richer (Margalef Richness Index; R1 = 8.007 ± 0.053) and Dob Ghar was evenly distributed (Pielou J Evenness Index; E = 0.940 ± 0.005) compared to other urban habitats studied. Eight foraging guilds were identified among the bird species. Insectivores were the most abundant bird species utilizing the urban dwelling habitats. carnivores/piscivores/insectivores utilized Dob Ghar forest, while more frugivores utilized Kamal Khan and Dob Ghar. Based on the data, it was concluded that subtropical broad-leaved urban forests are dynamic, complex, and of vital significance for a diverse range of bird species