Using a digital terrain model to calculate visual sunrise and sunset times

Keller, Chaim; Hall, John K.

doi:10.1016/s0098-3004(00)00058-3

Cited by 7 publications

(4 citation statements)

References 5 publications

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“…All experiments presented in this section are implemented for the coordinates 38 ∘ 27.0 N, 27 ∘ 13.2 E. During the test process, fixed and tracking solar panels' outputs were connected to separate but equal 12 V, 90 Ah gel batteries using maximum power point tracker (MPPT) charge controller as shown in Figure 6. The solar irradiance is measured by using a LiCor LI 210SA pyranometer [23]. The PV voltage PV , current PV , battery voltage , battery current , and sun trucker current, ST were measured and stored every minute using a data logger during the test process with an interval of 1 second.…”

Section: Resultsmentioning

confidence: 99%

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Optimization Controller for Mechatronic Sun Tracking System to Improve Performance

Engin

2013

Advances in Mechanical Engineering

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An embedded system that contains hardware and software was developed for two-axis solar tracking system to improve photovoltaic panel utilization. The hardware section of the embedded system consists of a 32-bit ARM core microcontroller, motor driver circuits, a motion control unit, pyranometer, GPS receiver, and an anemometer. The real-time control algorithm enables the solar tracker to operate automatically without external control as a stand-alone system, combining the advantages of the open-loop and the closed-loop control methods. The pyranometer is employed to continuously send radiation data to the controller if the measured radiation is above the lower radiation limit the photovoltaic panel can generate power, guaranteeing the solar tracking process to be highly efficient. The anemometer is utilized in the system to ensure that the solar tracking procedure halts under high wind speed conditions to protect the entire system. Latitude, longitude, altitude, date, and real-time clock data are provided by GPS receiver. The algorithm calculates solar time using astronomical equations with GPS data and converts it to pulse-width modulated motor control signal. The overall objective of this study is to develop a control algorithm that improves performance and reliability of the two-axis solar tracker, focusing on optimization of the controller board, drive hardware, and software.

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Section: Resultsmentioning

confidence: 99%

“…EOT in (5) is the "Equation Of Time" in minutes which can be calculated using the following equation [23]: EOT = 0.258 cos 7.416 sin − 3.648 cos 2 − 9.228 sin 2 ,…”

Section: Defining Elevation and Azimuth Angles Trajectoriesmentioning

confidence: 99%

Optimization Controller for Mechatronic Sun Tracking System to Improve Performance

Engin

2013

Advances in Mechanical Engineering

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“…Over the years, uses have ranged from determination of the earliest and latest times for daily Jewish prayers (Keller and Hall, 2000), to the siting of optimal coverage antennas for Israel TV's Channel 2, to planning of wind farms, to numeric delineation of watersheds, and myriad analyses of the landforms and landscape. Its primary usage has been as the most basic layer in almost every GIS (Geographic Information System) in Israel.…”

Section: Discussionmentioning

confidence: 99%

The 25-m DTM (Digital Terrain Model) of Israel

Hall¹

2008

Israel Journal of Earth Sciences

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Hall, J.K. 2008. The 25-m DTM (Digital Terrain Model) of Israel. Isr. J. Earth Sci. 57: 145-147.Between 1987 and 1993 an innovative method was used to generate a 25-m DTM (Digital Terrain Model) for Israel from 240 topographic map sheets at a scale of 1:50,000 without digitizing the 10-and 20-m contours. Altogether about 12,000 hours of interactive heads-up work on new PC-AT personal computers produced a 25-m grid using an innovative technique that colors the intervals between contours and converts the images to a grid. The software was written in FORTRAN IV. Approximately 87 of the topographic map sheets lie in Israel. The remainder are offshore (Mediterranean, Red Sea, Dead Sea, and Sea of Galilee) or in the adjacent areas of the Palestinian Authority, Jordan, Egypt, Lebanon, and Syria. This DTM was accomplished at an approximate cost of $0.75 per square kilometer (1600 heights). A poster is appended to this issue showing the hypsometrically colored as well as grayscale shaded relief for the area within the traditional Survey of Israel 1:250,000 scale North and South sheets. It also includes a useful graticule with the New Israel Grid, and the geographic and UTM coordinates (WGS-84 datum).

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“…Various algorithms for calculating the apparent movement of the Sun across the sky have been proposed in the literature, including simple [63,64] and more complex solutions [65][66][67][68]. The developed algorithms differ in accuracy and validity period, and local landform is also taken into account in some solutions to compute sunrise and sunset times [69]. This study relied on one of the five algorithms (no.…”

Section: Apparent Movement Of the Sun Across The Skymentioning

confidence: 99%

The Influence of Weather Conditions on the Optimal Setting of Photovoltaic Thermal Hybrid Solar Collectors—A Case Study

et al. 2020

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The potential absorption of solar energy in photovoltaic thermal (PVT) hybrid solar collectors at different tilt angles was compared in the present study. The optimal tilt angles were tested in three variants: during 1 day, 1 year and a period of 30 years. Simulations were performed based on actual weather data for 30 years, including average hourly total radiation, insolation and air temperature. The apparent movement of the Sun across the sky, solar radiation properties, and the electrical and thermal efficiency of a PVT collector were also taken into account in the simulation model. The optimal orientation of the absorber surface was determined by solving an optimization task. The results of the study indicate that in the long-term perspective, the collector’s performance is maximized when the absorber is positioned toward the south at an elevation angle of 34.1°.

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Using a digital terrain model to calculate visual sunrise and sunset times

Cited by 7 publications

References 5 publications

Optimization Controller for Mechatronic Sun Tracking System to Improve Performance

Optimization Controller for Mechatronic Sun Tracking System to Improve Performance

The 25-m DTM (Digital Terrain Model) of Israel

The Influence of Weather Conditions on the Optimal Setting of Photovoltaic Thermal Hybrid Solar Collectors—A Case Study

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