Wind energy has proven to be one of the quickest-developing sources of electricity generation in the world, with installed capacities surpassing 1,000 GW globally at the end of 2023. With the deployment of wind turbines in the power grids on unprecedented scales, the dynamics of wind turbines in response to grid and mechanical perturbations have become a serious issue to power system stability, reliability, and protection. The paper provides a detailed discussion on the behavior of wind turbine systems when disturbed including voltage dips, frequency variations, short-circuit faulting, lightning, mechanical stresses caused by turbulence, and islanding. We compare the dynamic properties of fixed-speed induction generators (FSIGs) and doubly-fed induction generators (DFIGs) and full-converter permanent magnet synchronous generators (PMSGs) with special focus on the low-voltage ride-through (LVRT) capability and frequency ride-through (FRT) requirements. The simulation models of time domain and frequency domain in MATLAB/Simulink and DIgSILENT Powerfactory are discussed and compared to field measurement results of a 150 MW onshore wind farm. The control measures such as crowbar protection, reactive current injection, active power modulation and virtual synchronous generator (VSG) schemes are considered. Findings show that high-order converter control can shorten voltage recovery time by as much as 47 percent relative to operation without converter control. As practical design tools, stability boundaries, protection coordination charts, and parametric sensitivity analyses are available. The paper ends with recommendations to operate grid-code compliant and mentions open research holes in the field of black-start capability and sub-synchronous resonance mitigation.

The selection of wall materials is critical factor influencing long- term building. This study aims to analyze the impact of using eco-friendly wall materials on building costs using the Life Cycle Cost (LCC) approach. The research compares Eco Hollow Block (EHB), which utilizes recycled multilayer plastic waste, with conventional red brick as a comparison material. The study was conducted on Sekolah Dasar Negeri (SDN) 002 buildings in Palembang. The LCC analysis includes initial construction cost, maintenance cost, and replacement cost during a 50-year building service life. The results indicate that the initial construction cost of EHB walls is higher than conventional brick. Furthermore, the total Life Cycle Cost of EHB is also higher due to its shorter service life, which requires periodic replacement within the analysis period. However, the use of EHB provides significant environmental benefits through plastic waste utilization and supports sustainable construction practices.

This study investigates the effects of varying aerosol concentrations, relative humidity (RH), phase functions, effective polarizability, and Ångström exponent (alpha) on North African desert aerosols, comparing OPAC 4.0 simulations with MODIS satellite data. Five model mixtures were analyzed for Mineral Accumulation Non-spherical (MIAN), Mineral Coarse Non-spherical (MICN), Mineral Nucleation Non-spherical (MINN), and water-soluble (WASO) components across concentration ranges. At 0% and 50% RH, OPAC 4.0 simulations showed that RH consistently increases alpha by +0.04 to +0.06 across all components due to hygroscopic growth. MICN and MINN models exhibited excellent internal consistency (R² > 0.99), with alpha values ranging from 0.086 to 0.133 (MICN) and 0.098 to 0.172 (MINN). WASO models produced alpha between 0.097 to 0.189 showing the strongest hygroscopic response. MIAN models showed variable alpha (-0.036 to 0.077), with Model 5 (alpha ≈ 0.04 to 0.05) now consistent with accumulation-mode dust. The turbidity coefficient (beta) remained stable for most OPAC models (0.127 to 0.301). Phase function analysis revealed two distinct angular scattering patterns: strong forward peaks for coarse dust and weaker, broader peaks for finer particles. Effective polarizability increased with concentration and RH. Validation using MODIS Deep Blue data (2000 to 2010) over ten North African locations yielded predominantly negative alpha values at eight sites (mean -0.284 to -0.086), confirming satellite detection of coarse-mode mineral dust. However, MODIS beta was quantitatively unreliable (R² 0.002 to 0.52, unphysical negative and extreme values), highlighting the challenge of bright desert surfaces. Positive alpha at Tamanrasset (+0.195) indicates mixed aerosols (dust + biomass burning). These findings provide a theoretical baseline (OPAC 4.0) and identify specific retrieval limitations (MODIS), improving the interpretation of satellite aerosol products over arid regions.

The paper is a detailed performance report on a solar-assisted single-effect lithium bromide-water (LiBr–H₂O) absorption cooling system installed and commissioned in Riyadh, Saudi Arabia -a typical hot-arid desert climate. The system combines evacuated tube solar collectors (ETCs) with a 35 kW absorption chiller, a thermal storage tank, and a backup gas heater. Twelve months of experimental data were taken to obtain the complete range of seasonal performance. Absorption chiller coefficient of performance (COP) varied between 0.61 in winter to 0.78 in peak-summer conditions, and the solar fraction was greater than 82% in June-August. On a sunny summer day, the entire system solar COP was 0.52. A techno economic analysis indicates a payback period of about 8.4 years as compared to a standard vapor-compression base, with an average CO₂ reduction per year of 18.7 tonnes. Parametric sensitivity tests test the effect of hot-water supply temperature (75–95 ^oC), cooling water temperature (28-36 ^oC) and chilled-water set point (6-12 ^oC) on chiller performance. The results of the simulation using TRNSYS 18 report a good match with measured values (RMSE ≤ 4.3%). These results substantiate the idea that solar absorption cooling can be thermally viable and cost-competitive in desert conditions with optimal system design and operational strategies.

The paper is a detailed performance report on a solar-assisted single-effect lithium bromide-water (LiBr–H₂O) absorption cooling system installed and commissioned in Riyadh, Saudi Arabia -a typical hot-arid desert climate. The system combines evacuated tube solar collectors (ETCs) with a 35 kW absorption chiller, a thermal storage tank, and a backup gas heater. Twelve months of experimental data were taken to obtain the complete range of seasonal performance. Absorption chiller coefficient of performance (COP) varied between 0.61 in winter to 0.78 in peak-summer conditions, and the solar fraction was greater than 82% in June-August. On a sunny summer day, the entire system solar COP was 0.52. A techno economic analysis indicates a payback period of about 8.4 years as compared to a standard vapor-compression base, with an average CO₂ reduction per year of 18.7 tonnes. Parametric sensitivity tests test the effect of hot-water supply temperature (75–95 ^oC), cooling water temperature (28-36 ^oC) and chilled-water set point (6-12 ^oC) on chiller performance. The results of the simulation using TRNSYS 18 report a good match with measured values (RMSE ≤ 4.3%). These results substantiate the idea that solar absorption cooling can be thermally viable and cost-competitive in desert conditions with optimal system design and operational strategies.