Abstract

Benghazi North power plant is subjected to large ambient air and seawater temperature fluctuations throughout the year, adversely impacting performance and generated power, consequently increasing CO₂ emission rates. Stabilizing the inlet air temperature and controlling the condenser inlet cooling water temperature under design conditions enhances and maintains performance and efficiency year-round. A single-effect water-lithium bromide absorption cycle powered by a solar parabolic trough collector was implemented. For efficient operation during non-sunny periods, an insulated thermal storage tank stores the thermal energy of the working medium, with an assisting heat supply from HRSG downstream exhaust gases to compensate any temperature drop inside the tank, which must not fall below 80°C to ensure effective cooling system operation. Model results indicate an improvement of overall efficiency by 3.635% and generated power by 12.18%, reducing greenhouse gas emissions by 3.537%. Annual power output increased by 9.767% and 7.728% for standalone gas turbines and combined cycle power plants, respectively, and net electricity production increased by 141,358,530 kWh/yr, saving $14,135,853 annually. Despite relatively high capital costs, the payback period is 1.48 years at an energy selling price of $0.1/kWh. The annual solar contribution factor of the parabolic trough system reached 91.896% during sunny periods. Keywords: Solar Cooling, Plant Efficiency, Renewable Energy, Pollution Reduction, Power Production.

Abstract

This paper implements and tests one type of renewable energy, solar energy. Enhancing the performance and efficiency of these sources has become increasingly important to compete with traditional fossil fuel sources in terms of efficiency, power quality, and production cost. The project explains in detail the methods used to increase solar energy efficiency. The primary approach is the sun tracking system, which continuously directs the solar panels toward the sun to maximize direct solar irradiation. Additionally, maintaining the optimal temperature for photovoltaic (PV) cells improves efficiency and prolongs their lifespan, achieved by integrating a cooling system with the sun tracking system. PV cells are sensitive to temperature variations. Increased ambient temperature and solar irradiance raise the PV cells’ operating temperature, reducing open-circuit voltage, fill factor, and power output for mono- and polycrystalline PV cells, potentially causing irreversible damage. Proper cooling is necessary to maintain operating temperature within manufacturer-specified values. This review presents passive cooling methods (heat pipe and fins) to enhance the performance of commercial PV and concentrated photovoltaic (CPV) cells. Results indicate that using the mentioned methods, solar panel efficiency improved by 15% with the tracking system, and after cooling, efficiency reached approximately 85%. Keywords: Solar cells, Solar rays, Sun tracking system, Cooling system, Photovoltaic

Abstract

Housing is defined as the basic cell that constitutes the living fabric of the city, where the individual interacts with the community and the surrounding environment. Public housing refers to dwellings built and owned by the state and provided to beneficiaries for short or long periods at affordable prices, aiming to achieve justice and equality among citizens in accessing housing and to reduce costs. Different terms are used for this type of housing such as: social housing, low-cost housing, popular housing, and housing for the disadvantaged. Government approaches vary in providing such housing depending on their capacities and development policies, yet the common objective remains to balance the housing market and secure adequate housing. This study evaluates the performance of public housing in Benghazi city, focusing on the 7000 housing units project, by applying Space Syntax theory as an effective tool to analyze spatial configurations, study residents’ behavior, and assess the distribution patterns of housing units and neighborhood layouts. The findings show that space syntax analysis revealed distinctive characteristics of housing units and apartment layouts, highlighting similarities and differences among them, as well as the social and cultural relations expressed by these spatial patterns. The results also demonstrated the project’s adequacy in meeting the needs of target families, its contribution to improving the urban environment, and its role in creating more efficient public spaces through pedestrian and vehicular networks. The study concludes that the 7000 housing units project in Benghazi demonstrates spatial and environmental characteristics that respond to residents’ needs and strengthen the city’s urban structure. Keywords: Public housing, Space syntax theory, Spatial analysis, Benghazi city, Urban environment.

Abstract

Information and results from previous studies on different concrete additives were collected and compared in terms of their effects on concrete properties such as density and compressive strength. The aim of this research is to select the most appropriate additive regarding its effect on concrete resistance, light weight, material cost, and availability in areas near the work site. The study concluded that iron furnace slag is abundantly available, with quantities estimated at about 300 kg per ton of iron ore, making it a cheap and easily accessible material. Sawdust is also available and relatively low-cost compared to other materials, while palm fronds are abundant in Libya but expensive due to the difficulty of grinding them according to the required gradation. This subject has significant economic importance since it contributes to reusing waste materials in structural applications, especially with increasing population density and the challenges of waste disposal and its negative environmental impacts. Using furnace slag as a coarse aggregate alternative reduces environmental effects, while sawdust and palm fronds are considered environmentally friendly alternatives as they are natural materials and do not cause harmful residues when mixed with concrete. The results showed that increasing the percentages of these additives (furnace slag, sawdust, and palm fronds) generally led to lower compressive strength and reduced density of concrete, while providing new properties such as light weight. Keywords: Concrete, Concrete additives, Furnace slag, Sawdust, Palm fronds, Compressive strength.