A microprocessor-based control system is designed and constructed to control the position of equa... more A microprocessor-based control system is designed and constructed to control the position of equatorially mounted sun tracker. The system was designed and implemented on an Z-80 based microprocessor. This paper gives the general hardware and software along with the circuitry. The tracking is carried out by utilizing the astronomical co-ordinates of the sun.
An automatic global and direct solar spectral irradiance system has been designed based on two LI... more An automatic global and direct solar spectral irradiance system has been designed based on two LICOR spectroradiometers equipped with fibre optics and remote cosine sensors. To measure direct irradiance a sun tracker based on step motors has been developed. The whole system is autonomous and works continuously. From the measurements provided by this system a spectral irradiance database in the 330–1100 nm range has been created. This database contains normal direct and global horizontal irradiances as well as diffuse irradiance on a horizontal plane, together with total atmospheric optical thickness and aerosol optical depth.
In this paper we describe the realization of a programmed sun tracker for spectroscopic use. The ... more In this paper we describe the realization of a programmed sun tracker for spectroscopic use. The precision of the tracking is 10−3 degree. With this instrument, we are able to record ozone atmospheric spectra in the 10 μm region.The sun is used as the IR source of a high resolution (Δv = 5 MHz) Laser Heterodyne Spectrometer. Examples of such spectra are presented.
Measurements of attenuation at 230 GHz through the total atmosphere due to the presence of oxygen... more Measurements of attenuation at 230 GHz through the total atmosphere due to the presence of oxygen and water vapour molecules, clouds and rain are presented and discussed. The measurements were carried out using a specially designed superhetrodyne receiver mounted on a sun tracker. Simultaneous measurements were also carried out at 13 GHz. For a measuring site close to sea level the "clear-sky" zenith attenuation was found to be given by A(dB)=0.35+0.95W, where W is the precipitable water in cms. When the ground temperature was below about 7°C most cloud and overcast gave ¿ 0.5 dB attenuation whereas with a ground temperature greater than 13°C cloud attenuation was 8 to 10 times greater.
Nowadays power supply systems based on photovoltaic cells have two main drawbacks, even the prima... more Nowadays power supply systems based on photovoltaic cells have two main drawbacks, even the primary energy is free and renewable. They are: production cost and efficiency. In order to increase their efficiency, it should be interesting that the energy transfer between cells and load was done at maximum level. In this paper the use of a sun tracker system is presented as an additional improvement applied to a photovoltaic installation that works under a maximum power point tracking (MPPT) control technique. A 50 W-prototype has been assembled. Some experimental results are also included in order to validate the whole system.
... paper is presenting an optimizing control algorithm for PV soft sun trackers movement. It is ... more ... paper is presenting an optimizing control algorithm for PV soft sun trackers movement. It is intending to establish the minimum number of movements with a high level of energy generation. II. BASIC CONSIDERATIONS It is known that the energy collected by a solar panel is ...
Page 1. Design and Implementation of a Fuzzy Logic Computer-Controlled Sun Tracking System Hasan ... more Page 1. Design and Implementation of a Fuzzy Logic Computer-Controlled Sun Tracking System Hasan A. Yousef Department of Electrical Engineering University of Qatar Doha, QATAR, P. 0. Box 2713 h.yousef@qu.edu.qa ...
A microcontroller based automatic sun tracker combined with a new solar energy conversion unit is... more A microcontroller based automatic sun tracker combined with a new solar energy conversion unit is designed and implemented. The automatic sun tracker is implemented with a DC motor and a DC motor controller. The solar energy conversion unit consists of an array of solar panels, a step-up chopper, a single-phase inverter, an AC mains power source and a microcontroller based control unit. The novelty of this unit is that the switching device of the chopper is not only used for power conversion but also for maximum power point (MPP) detection. In the existing MPP trackers, the MPP is detected by hardware. The parameters of the hardware subject to the changes of the environmental conditions. In the new unit the MPP is determined by simple embedded software with a current sweep approach. With this new approach, the modularization of the conversion from solar power to electric power at its maximum power point can be made more compact and more reliable.
Renewable & Sustainable Energy Reviews, Jan 1, 2009
Finding energy sources to satisfy the world's growing demand is one of society's foremost challen... more Finding energy sources to satisfy the world's growing demand is one of society's foremost challenges for the next half-century. The challenge in converting sunlight to electricity via photovoltaic solar cells is dramatically reducing $/watt of delivered solar electricity. In this context the sun trackers are such devices for efficiency improvement.The diurnal and seasonal movement of earth affects the radiation intensity on the solar systems. Sun-trackers move the solar systems to compensate for these motions, keeping the best orientation relative to the sun. Although using sun-tracker is not essential, its use can boost the collected energy 10–100% in different periods of time and geographical conditions. However, it is not recommended to use tracking system for small solar panels because of high energy losses in the driving systems. It is found that the power consumption by tracking device is 2–3% of the increased energy.In this paper different types of sun-tracking systems are reviewed and their cons and pros are discussed. The most efficient and popular sun-tracking device was found to be in the form of polar-axis and azimuth/elevation types.
A sun tracking system for use with various dimensioned collectors or platforms is discussed. Sun ... more A sun tracking system for use with various dimensioned collectors or platforms is discussed. Sun position sensing is successfully performed using phototransistors mounted in a simple structure. Some problems associated with this technique which were successfully overcome are mentioned. An electrical circuit block diagram with description is given as well as the tracking system's performance when connected to a 2.34-m2 cylindrical parabolic collector. With this arrangement, the tracker consumes approx. 1 W of electrical power which is supplied by a small panel of solar cells with a rechargeable battery as a back-up and night time supply.
A microprocessor-based control system is designed and constructed to control the position of equa... more A microprocessor-based control system is designed and constructed to control the position of equatorially mounted sun tracker. The system was designed and implemented on an Z-80 based microprocessor. This paper gives the general hardware and software along with the circuitry. The tracking is carried out by utilizing the astronomical co-ordinates of the sun.
An automatic global and direct solar spectral irradiance system has been designed based on two LI... more An automatic global and direct solar spectral irradiance system has been designed based on two LICOR spectroradiometers equipped with fibre optics and remote cosine sensors. To measure direct irradiance a sun tracker based on step motors has been developed. The whole system is autonomous and works continuously. From the measurements provided by this system a spectral irradiance database in the 330–1100 nm range has been created. This database contains normal direct and global horizontal irradiances as well as diffuse irradiance on a horizontal plane, together with total atmospheric optical thickness and aerosol optical depth.
In this paper we describe the realization of a programmed sun tracker for spectroscopic use. The ... more In this paper we describe the realization of a programmed sun tracker for spectroscopic use. The precision of the tracking is 10−3 degree. With this instrument, we are able to record ozone atmospheric spectra in the 10 μm region.The sun is used as the IR source of a high resolution (Δv = 5 MHz) Laser Heterodyne Spectrometer. Examples of such spectra are presented.
Measurements of attenuation at 230 GHz through the total atmosphere due to the presence of oxygen... more Measurements of attenuation at 230 GHz through the total atmosphere due to the presence of oxygen and water vapour molecules, clouds and rain are presented and discussed. The measurements were carried out using a specially designed superhetrodyne receiver mounted on a sun tracker. Simultaneous measurements were also carried out at 13 GHz. For a measuring site close to sea level the "clear-sky" zenith attenuation was found to be given by A(dB)=0.35+0.95W, where W is the precipitable water in cms. When the ground temperature was below about 7°C most cloud and overcast gave ¿ 0.5 dB attenuation whereas with a ground temperature greater than 13°C cloud attenuation was 8 to 10 times greater.
Nowadays power supply systems based on photovoltaic cells have two main drawbacks, even the prima... more Nowadays power supply systems based on photovoltaic cells have two main drawbacks, even the primary energy is free and renewable. They are: production cost and efficiency. In order to increase their efficiency, it should be interesting that the energy transfer between cells and load was done at maximum level. In this paper the use of a sun tracker system is presented as an additional improvement applied to a photovoltaic installation that works under a maximum power point tracking (MPPT) control technique. A 50 W-prototype has been assembled. Some experimental results are also included in order to validate the whole system.
... paper is presenting an optimizing control algorithm for PV soft sun trackers movement. It is ... more ... paper is presenting an optimizing control algorithm for PV soft sun trackers movement. It is intending to establish the minimum number of movements with a high level of energy generation. II. BASIC CONSIDERATIONS It is known that the energy collected by a solar panel is ...
Page 1. Design and Implementation of a Fuzzy Logic Computer-Controlled Sun Tracking System Hasan ... more Page 1. Design and Implementation of a Fuzzy Logic Computer-Controlled Sun Tracking System Hasan A. Yousef Department of Electrical Engineering University of Qatar Doha, QATAR, P. 0. Box 2713 h.yousef@qu.edu.qa ...
A microcontroller based automatic sun tracker combined with a new solar energy conversion unit is... more A microcontroller based automatic sun tracker combined with a new solar energy conversion unit is designed and implemented. The automatic sun tracker is implemented with a DC motor and a DC motor controller. The solar energy conversion unit consists of an array of solar panels, a step-up chopper, a single-phase inverter, an AC mains power source and a microcontroller based control unit. The novelty of this unit is that the switching device of the chopper is not only used for power conversion but also for maximum power point (MPP) detection. In the existing MPP trackers, the MPP is detected by hardware. The parameters of the hardware subject to the changes of the environmental conditions. In the new unit the MPP is determined by simple embedded software with a current sweep approach. With this new approach, the modularization of the conversion from solar power to electric power at its maximum power point can be made more compact and more reliable.
Renewable & Sustainable Energy Reviews, Jan 1, 2009
Finding energy sources to satisfy the world's growing demand is one of society's foremost challen... more Finding energy sources to satisfy the world's growing demand is one of society's foremost challenges for the next half-century. The challenge in converting sunlight to electricity via photovoltaic solar cells is dramatically reducing $/watt of delivered solar electricity. In this context the sun trackers are such devices for efficiency improvement.The diurnal and seasonal movement of earth affects the radiation intensity on the solar systems. Sun-trackers move the solar systems to compensate for these motions, keeping the best orientation relative to the sun. Although using sun-tracker is not essential, its use can boost the collected energy 10–100% in different periods of time and geographical conditions. However, it is not recommended to use tracking system for small solar panels because of high energy losses in the driving systems. It is found that the power consumption by tracking device is 2–3% of the increased energy.In this paper different types of sun-tracking systems are reviewed and their cons and pros are discussed. The most efficient and popular sun-tracking device was found to be in the form of polar-axis and azimuth/elevation types.
A sun tracking system for use with various dimensioned collectors or platforms is discussed. Sun ... more A sun tracking system for use with various dimensioned collectors or platforms is discussed. Sun position sensing is successfully performed using phototransistors mounted in a simple structure. Some problems associated with this technique which were successfully overcome are mentioned. An electrical circuit block diagram with description is given as well as the tracking system's performance when connected to a 2.34-m2 cylindrical parabolic collector. With this arrangement, the tracker consumes approx. 1 W of electrical power which is supplied by a small panel of solar cells with a rechargeable battery as a back-up and night time supply.
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