Journal of Solar Energy Research
Volume:6 Issue: 2, Spring 2021

Attention to daylighting methods in traditional houses is one of the prominent features of the rich vernacular architecture of Iran. Therefore, recognizing the experiences of the predecessors about the transparent surfaces of the indigenous houses of Tabriz city which is located in the cold-dry climate of Iran and updating the previous strategies can improve the quality of daylight in contemporary buildings. This paper examines physical elements of the open and closed spaces in the traditional houses of Tabriz and their role in increasing the quality of daylighting and sunlight hours in the interior spaces, analyzes the logical relationship between the components of transparent surfaces and the closed spaces associated with them. The purpose of this study is to recognize quality and sunlight hours of traditional houses of Tabriz and to provide suggestions and design patterns for closed spaces in this city buildings and cold-dry climate buildings in Iran. The research method is based on data collection, field studies and the use of daylight analysis software to check the illuminance of the spaces, sunlight hours and shading in the yard throughout the year. Standards related to daylight quality and statistical methods were used to analyze the obtained information. The results indicate the existence of a logical relationship between some elements of window and room in the closed spaces related to windows that provide adequate daylight, which is presented as proposed design patterns

Electric springs (ES) are often known to be demand-side power management systems in decentralized grids with renewable energy sources, which, due to their nature, inject unreliable electricity power into the system. The second type of electrical spring (ES_2) produces an intelligent load by placing it next to a sensitive load, which, in addition to regulating the voltage level, will optimize various parameters of the power quality for the sensitive load. In imbalance grids with harmonic voltages and local non-linear load, where conventional controllers are used, the intelligent load cannot improve the power quality for a sensitive load. In this paper, a proportional resonance (PR) controller is used to regulate both the voltage level and the source voltage imbalances due to the least tracking error in the sinusoidal mode as well as a repetitive controller (RC) is designed to reduce THD and improve the power factor thanks to its infinite poles on the imaginary axis. Finally, these two suggested controllers were tested simultaneously in three-phase and single-phase grids by mathematical and machine simulation. The grid considered in this paper has harmonics up to order 17 and voltage fluctuations in the range of 0.954 to 1.1 per unit, as well as a local non-linear load with 100% of the sensitive load size and, in the three-phase mode, the grid, has unbalanced three-phase load. The results of the MATLAB simulation for electrical spring, controlled by the PR RC controller, which is a combination of two proportional resonance controllers and a repetitive controller in both three and single-phase mode Note that the sensitive load voltage is completely adjusted to its reference value, THD reduces by 80.31% compared to the uncompensated condition and will be less than the value defined by the IEEE standard and the power factor rises up to near the unit.

Solar energy is one of the most important renewable sources and Iran is an ideal place for the use of solar energy. This form of renewable energy can be utilized through both active and passive systems. This research aimed to investigate the impact of the most common methods of using solar energy in passive ways, which are sunspaces (glazed balcony and atrium) on reducing energy consumption of two residential buildings in Iran-Mashhad city with cold semi-arid climate. The method of the research is descriptive, analytical and practical. The data collection was based on literature review, case study and climate data from meteorological station of Mashhad and reputable global web sites during a period of (2004-2018) for a short term and (1944-2020) for a long term. Also, a combination of the Echotect, Climate consultant and Autodesk Revit 2020 with insight 360 plug-in has been used. The Echotect software is used for optimum orientation analysis function and Climate Consultant is used for building design strategies appropriate for the unique characteristics of that climate of Mashhad. In this paper analyzed annual energy consumption in case A (with balcony and without balcony) and in case B (with atrium and without atrium). Results indicated that glazed balconies and atrium in two buildings could reduce the energy consumption by 41.33% in case A and by 26.28% in case B with respect to the reference building, respectively. Overall, using sunspaces can have a significant effect at city scale, by repetition in cold semi-arid climates. Thus, these systems can be considered by the designer in the first step of a designing project.

One of the ways to improve the performance of simple solar stills is to use energy storage materials to store energy during the day and use it at night. Several energy storage materials have been studied by researchers, one of which is the use of sand. In this research, the improvement of a simple solar still performance has been studied using sand with different grain size distribution inside its basin. For this purpose, four solar still were made in Esfarayen (latitude 36.20 and longitude 57.67), Iran, and the effect of sand grain size distribution on its performance was studied in four treatments. The height of sand and water was 10 cm and the average grain size of treatments was considered 6.9, 2.8, 1.1 and 0.7 mm. The experiments were performed for 4 days in mid-August 2020. The results showed that the sand-containing treatment with an average grain size of 2.8 mm had better productivity and thermal efficiency than other cases where the average grain size of the used sand was larger or smaller. Therefore, grain size distribution of the sand seems to affect the performance of simple solar stills and there is an optimal amount for grain size.

Renewable energy is a remarkable developing potential in Vietnam, in which solar photovoltaic (PV) energy is rapidly invested by investors in and out of the country in recent years. Specially, the solar radiation in Southern area is more tremendous comparing with other parts in Vietnam. Developing the PV energy is very essential and results to national economic, social and technical benefits. However, the state of uncontrollable developing rooftop PV in residential households and entrepreneurs affects national power system in the area. In this study, the potentials of rooftop PV energy in Hau Giang province – being located in Southern part and occupying about 0.5% of total area in Vietnam (1,608km2) - is evaluated by statistical methods, analysist methods and online map-based applications. As a results, total rooftop suitable area and the average peak capacity PV power potential in Hau Giang province are approximately 15.79km2 and 1,882.3MW/year, respectively. Besides, power system steady state stability is analysed via commercial software ETAP when connecting rooftop PV power station in Hau Giang province and a study case is proposed to verify economic and social effects of a pilot project.

The rural fabric of every village is affected by both human interventions and environmental factors. Also, climate and nature can both influence the village structure. In other words, the climatic and vernacular architecture of rural areas are mutually interrelated, and the villages have to adapt to their environment to survive, provide welfare, and prevent the immigration of villagers to cities sustainably.A very important factor in the sustainability of vernacular buildings is the orientation of rural buildings and the possibility of using solar and wind energy, an issue that has been considered by vernacular builders throughout history. Limited sources of energy and reliance on renewable energy have made the inhabitants design and build their vernacular buildings according to climatic conditions to reduce energy consumption. In this regard, the proper orientation of the buildings to prevent energy loss is of particular importance.This study tries to discuss the factors influencing the orientation of rural housing. The vernacular architecture and the proper orientation of houses in Masuleh (Gilan province, north of Iran) and Uraman Takht (Kurdistan Province, west of Iran) villages are also discussed. The possibility of using key factors of vernacular architecture principles in similar climates is also discussed. Energy simulations with the Honeybee plugin are used as a tool for optimization orientation. Honeybee runs simulations with EnergyPlus through Rhino and Grasshopper software and visualizes results by the Ladybug plugin. For the finding best orientation, the parameters which related to building energy performance defined in honeybee plugin such as windows size and location, wall U-value, glazing construction U-value, glazing g-value, cooling and heating set-point. After energy modeling of building for the case study, the energy simulation has been conducted with EnergyPlus engine and the Ladybug plugin visualized the results.