Design and construction of a solar tracking system

Al-Naima, Fawzi M.; Yaghobian, N.A.

doi:10.1016/0741-983x(90)90072-a

Cited by 24 publications

(13 citation statements)

References 7 publications

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“…From the literature, typical solar tracking errors of 0.1° -0.3° [31], 0.2° [32], 0.4° [33], 0.6° -0.7° [34], less than 1° [35], 1° [36] and ±1° -2° commercially [37] were identified. Error due to wind loading is also a measurable quantity [37].…”

Section: Solar Tracking Errormentioning

confidence: 99%

The efficiency of an open-cavity tubular solar receiver for a small-scale solar thermal Brayton cycle

Roux¹,

Bello‐Ochende²,

Meyer³

2014

Energy Conversion and Management

121

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The first law and second law efficiencies are determined for a stainless steel closed-tube open rectangular cavity solar receiver. It is to be used in a small-scale solar thermal Brayton cycle using a micro-turbine with low compressor pressure ratios. There are many different variables at play to model the air temperature increase of the air running through such a receiver. These variables include concentrator shape, concentrator diameter, concentrator rim angle, concentrator reflectivity, concentrator optical error, solar tracking error, receiver aperture area, receiver material, effect of wind, receiver tube diameter, inlet temperature and mass flow rate through the receiver. All these variables are considered in this paper. The Brayton cycle requires very high receiver surface temperatures in order to be successful.These high temperatures, however, have many disadvantages in terms of heat loss from the receiver, especially radiation heat loss. With the help of ray-tracing software, SolTrace, and receiver modelling techniques, an optimum receiver-to-concentrator-area ratio of A' ≈ 0.0035 was found for a concentrator with 45° rim angle, 10 mrad optical error and 1° tracking error. A method to determine the temperature profile and net heat transfer rate along the length of the receiver tube is presented. Receiver efficiencies are shown in terms of mass flow rate, receiver tube diameter, pressure drop, maximum receiver surface temperature and inlet temperature of the working fluid. For a 4.8 m diameter parabolic dish, the larger the receiver tube diameter and the smaller the mass flow rate through the receiver, the higher the receiver surface temperature and the less efficient the collector becomes. However, the smaller the receiver tube diameter, the higher the pressure drop through the tube and the smaller the second law efficiency. It was found that the 2 receiver with larger tube diameter would perform better in a solar thermal Brayton cycle. An overall solar-to-heat efficiency of between 45% and 70% is attainable for the solar collector using the open-cavity receiver.Keywords: solar, receiver, cavity, tracking, Brayton, efficiency 1.Introduction and background The solar thermal Brayton cycleThe closed Brayton cycle was developed in the 1930s for power applications [ The open Brayton cycle uses air as working fluid, which makes this cycle very attractive for use in water-scarcecountries. The open and direct solar thermal Brayton cycle is shown in Fig. 1 [2]. The parabolic dish concentrator is used to reflect and concentrate the sun's rays onto the receiver aperture so that the solar heat can be absorbed by the inner walls of the receiver. The heat is then transferred to the working fluid (air). The compressor increases the air pressure before the air is heated in the receiver. The compressed and heated air expands in the turbine, which produces rotational power for the compressor and the electric load.In the recuperator, hot exhaust air preheats the colder air before it enters the receiver. For the so...

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Section: Solar Tracking Errormentioning

confidence: 99%

The efficiency of an open-cavity tubular solar receiver for a small-scale solar thermal Brayton cycle

Roux¹,

Bello‐Ochende²,

Meyer³

2014

Energy Conversion and Management

121

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“…The experimental results demonstrated that the proposed system outperformed a conventional one-axis tracking system [12].…”

Section: Introductionmentioning

confidence: 80%

Solar Orientation Measurement Systems with Integrated Solar Cells

Chiang¹,

Lee²,

Chou³

2009

TOBCTJ

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This paper presents a novel approach for estimating the position of the sun by measuring the output voltage signals of two solar cell arrays orientated orthogonally to one another. Each array comprises a symmetrical arrangement of six cells inclined at angles of either 15°, 45° or 75° to the horizontal, respectively. As the position of the sun varies over the course of the day, a change is induced in the output voltage of each of the solar cells within the array. It is shown that the output voltage of any cell (V) varies as a linear function of the included angle between it and the solar cell with the maximum output voltage (V max ). A mathematical correlation is derived to express the relationship between the comparative output voltage of each solar cell (V/V max ) and the solar position. The sun's position is then computed by averaging the elevation angles derived from the comparative output voltages of all of the cells within the array. It is shown that both the zenith angle and the latitude angle of the sun can be accurately determined by deploying the measurement system such that one solar cell array is aligned in the East-West (E-W) direction while the other is orientated in the North-South (N-S) direction.

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“…It was shown that the above-mentioned system was capable of better tracking than that obtained by a conventional sensorcontrolled system [4]. Several years later, Lorenz proposed a window glazing method wherein a set of design guidelines for window glazing that rejected solar radiation during the summer but accepted it during the winter.…”

Section: Review Of Solar Tracking Systemmentioning

confidence: 99%

Maximization of Photovoltaic Energy Generation by Time and Location Based Sun Tracking System

Baig¹,

Tjprc²

2018

IJMPERD

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This paper presents time and location based sun tracking system which maximizes the exposure of the sun to the photovoltaic panel used for energy generation. This unprecedented tracking system is location and time agnostic which facilitates an easy installation at any place without any manual calibration. The system works on Program Logic Controller, which is programmed in such a way that it calculates the position (inclination) of the panel based on the current time and location. An experimental prototype is built and deployed for which calculations and inclination control approach is presented, as a proof. It is found that the average power generation is increased using the proposed novel tracking system.

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Design and construction of a solar tracking system

Cited by 24 publications

References 7 publications

The efficiency of an open-cavity tubular solar receiver for a small-scale solar thermal Brayton cycle

The efficiency of an open-cavity tubular solar receiver for a small-scale solar thermal Brayton cycle

Solar Orientation Measurement Systems with Integrated Solar Cells

Maximization of Photovoltaic Energy Generation by Time and Location Based Sun Tracking System

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