Environmental, economic and energetic benefits from implantation of several modes of solar collector movements

In this research, the performance of a moving solar system on two axes was studied, the east-west axis, this axis represents the tilt angle of the solar collector. The other movement is the surface's rotation around the perpendicular axis on the surface in the east and west directions, which in turn represents the azimuth angle of the solar collector. All possibilities for these movements were also studied, in order to reach the optimal option, which in turn depends on the importance of alication and the available space on the one hand, and the economic conditions on the other hand. The maximum value of solar radiation intensity was adopted as a guide to compare the performance of six options for tracking systems. Despite the high costs of tracking systems, they often have a positive economic return, as these systems increase the efficiency of the solar system, whether it is electric or thermal twice, the first one by increasing the intensity of the solar radiation incident on the solar collector, and the second one by increasing the optical efficiency of the solar collectors and thus increasing the overall efficiency of the device. The percentage of increase in the sixth type of solar energy is about 38% compared to the fixed mode. The minimum optical efficiency of the dual tracking mode has been found as 84%, while for fixed mode is about 48%.

Analysis and correlation of ultraviolet solar radiation from routine meteorological measurements over Egypt

For three years (1990-92) measurements of the monthly average daily global, G, and ultraviolet, UV, solar radiation incident on a horizontal surface at Cairo (30°15'N, 31°17'E) and Aswan (23°58'N, 32°47'E) are presented. processed and analysed. It was found that the computed monthly average daily values for the obtained solar radiation components, G and UV, were (18.1 MJ/m2, 0.55 MJ/m2, for Cairo and (22.1 MJ/m2, 0.71 MJ/m2, for Aswan. The effect of atmospheric dust on the measured solar radiation components is also investigated and discussed. The ratio of the ultraviolet to global radiation (UV/G) are calculated and compared with other sites in the Arabian Peninsula. A regression analysis has been done to find a correlation between G and UV at the selected sites during the three year period and the recommended correlation equations have also been stated. Since the meteorological measurements of UV solar radiation are not available over Egypt. except at Cairo (Lower Egypt) and Aswan (Upper Egypt) stations, our correlation equations can be used to calculate this component from the available global solar radiation measurements at any site in the two zones of Upper and Lower Egypt.

Semi-transparent Photovoltaic Thermal Greenhouse System Combined with Earth Air Heat Exchanger for Hot Climatic Condition

Semi-transparent photovoltaic thermal (SPVT) greenhouse system combined with an earth air heat exchanger (EAHE) has been developed to make the system sustainable. The system is designed to cultivate plants in a hot climatic condition, where green net is provided which bifurcates the enclosed space of the greenhouse into zone-1 and zone-2, and this green net cuts the solar radiation incident on the plants. The influence of air changes in zone-1, mass flow rate of air flowing through EAHE, and packing factor on PV cell, air of the greenhouse, and the plant temperatures is investigated for a typical harsh summer day by using periodic model of these parameters. Further, for a holistic performance assessment of this SPVT greenhouse, exergy, thermal load leveling, and decrement factor are evaluated. Results indicate that the optimum temperature range for plant growth (30 °C- 37 °C) within the greenhouse can be achieved through a combination of ventilation in zone-1 and integration of EAHE. The temperature of plants reduced by 9 °C for 30 air changes in zone-1, and the temperature reduces further by 24 °C when EAHE having a flow rate of 0.5 kg/s is operated. The SPVT greenhouse system also generates 128 kWh of daily overall exergy that makes the system sustainable.

Thermal Performance of Nanofluid Flow Inside Evacuated Tube Solar Collector

Solar collectors are systems for absorbing the sun's radiant energy and converting it into heat. The working principle of solar collectors are relying on the solar radiation incident upon the transparent surface, and the collected radiation heat is stored within the operating fluid. However, the conventional operating fluid is less than satisfactory in term of promoting the thermal efficiency of solar collector. Consequently, the aim of this paper is to investigate the use of nanofluid as an operating fluid in a single end evacuated solar collector. The expectation is that the flow behavior of nanofluid can lead to the improvement of thermal efficiency of solar collector. The design of solar collector is carried out using Gambit software and the heat transfer characteristics are simulated by nanofluid flow with 1%, 3% and 5% volumes by ANSYS Fluent software. The results demonstrate good agreement with existing experimental results. The numerical analysis shows the improvement of collector performance compared to pure water fluid. The results show that by increasing the nanoparticles volume fraction the efficiency of the collector improves significantly.

Evaluating the impact of solar envelope zoning solar access and development density. A study of mid-rise buildings in Toronto

The global population is growing exponentially with a trend of people moving to cities, resulting in rapid growth in the urban built environment. It is critical for urban planners to promote health, comfort, and resiliency in urban areas through integrated solar access requirements within zoning regulations. This paper evaluates the potential for the Solar Envelope Zoning (SEZ) method as a zoning tool in Toronto, Canada. The SEZ method is compared with current zoning regulations and mid-rise buildings guidelines using parametric modelling to establish the solar envelope on a typical building site. The resulting development density and solar radiation incident on adjacent building facades is evaluated. A similar study is performed on a site that is currently proposed for development along one of Toronto’s main avenues. The results show that by redefining solar access requirements to include climate dependent variables, SEZ can provide competitive development density while improving solar access.

Evaluating the impact of solar envelope zoning solar access and development density. A study of mid-rise buildings in Toronto

The global population is growing exponentially with a trend of people moving to cities, resulting in rapid growth in the urban built environment. It is critical for urban planners to promote health, comfort, and resiliency in urban areas through integrated solar access requirements within zoning regulations. This paper evaluates the potential for the Solar Envelope Zoning (SEZ) method as a zoning tool in Toronto, Canada. The SEZ method is compared with current zoning regulations and mid-rise buildings guidelines using parametric modelling to establish the solar envelope on a typical building site. The resulting development density and solar radiation incident on adjacent building facades is evaluated. A similar study is performed on a site that is currently proposed for development along one of Toronto’s main avenues. The results show that by redefining solar access requirements to include climate dependent variables, SEZ can provide competitive development density while improving solar access.

Validation and comparison of incoming solar radiation satellite databases on the Atlantic coast of Central Africa.

<p>Solar radiation incident on the Earth's surface is important for the functioning of tropical forests, as it affects the availability of light and water. Due to the lack of in-situ data in tropical forest environments, satellite products and reanalyses are the only ways to estimate solar radiation on a regional scale. An intercomparison of five satellite databases including CERES-EBAF, CERES-SYN1deg, CMSAF-SARAH, CMSAF-CLARA, CAMS-JADE as well as the ERA5 reanalysis, is carried out for the Atlantic coast of Central Africa by evaluating them against two in-situ data sets: the monthly FAOCLIM2 database and original infra-daily data from meteorological stations set up within the framework of ecoclimatic projects. From this inter-comparison we show the differences between these six products and with in-situ data from monthly to daily scales. We also show that the Atlantic coast of Central Africa receives the least amount of solar radiation in all products compared to other regions of Central Africa.</p>

Optimization of the distance between the rows in solar collectors’ arrays

The article presents some results of the analysis of the influence of the distance between the collectors’ rows in thermal solar systems on the degree of self-shading. For the purposes of the study, the dimensionless ratio Ks between the required minimum distance between the rows, guaranteeing the absence of self-shading, and the height of the collectors, was used. A simulation study was performed for specific climatic conditions and the annual solar radiation incident on the collectors’ array at different degrees of self-shading was determined. Its annual financial equivalent for various alternative heat sources (electricity, natural gas, wood pellets, district heating and gas oil) was assessed, as well as the necessary investment costs for construction of the solar system. A regression relationship between the coefficient of net present value NPVQ and Ks was derived and its optimal values were established, which ensure the achievement of maximum economic efficiency of the system operation for the considered replaced heat sources.

Analysis of Mountain Relief for the Causes of Snow Avalanches

The descent of avalanches is quite a usual phenomenon for the Ukrainian Carpathians, as well as for the conditions of mountain terrain in general. The Gorgany range of the Carpathian mountains is a typical avalanche-prone territory. Avalanches cause significant damage to forestry and may lead to casualties. Therefore, descent of avalanches has for a long time been a subject of fundamental research in geomorphology, meteorology, topography, photogrammetry and GIS technologies. Using photogrammetric mapping, we analyzed the causes of the descent of one of the largest avalanches in the Ukrainian Carpathians for the past 15 years. The avalanche fell from Poliensky mountain in the Gorgany mountain range in 2006, causing destruction of a great amount of forest. The main causes of avalanches were divided into two groups, the first including more or less stable factors caused by impact of terrain and somewhat less by solar radiation and the second group comprising meteorological factors, such as prolonged snowstorms and snowfall, that is, different fluctuations in weather. The main attention was paid to the first group of factors. For this purpose, a digital terrain model (DTM) of the study area was developed, visualizing the terrain, demonstrating the studied slope of the mountain along which the avalanche slid. According to the digital model, we developed maps of the steepness andexposition of the slope. Also we calculated the coefficient for solar radiation incident on the slope and which depends on the height of the Sun above the horizon and the coordinates of the slope. Using these data, the illuminance map of the Poliensky mountain area was developed. Studies conducted using GIS technologies led to the conclusion that the determining factors that triggered the powerful avalanche from Poliensky mountain were the great steepness and length of the slope, as well as the absence of forest at the top of the mountain, i.e. at the beginning of the avalanche track.