Law of motion of reflectors for a linear Fresnel plant

Cucumo, Mario Antonio; Ferraro, Vittorio; Kaliakatsos, Dimitrios; Mele, Marilena; Nicoletti, Francesco

doi:10.18280/ijht.35sp0111

Cited by 11 publications

(11 citation statements)

References 6 publications

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“…In a traditional Fresnel linear system, the end losses are caused by the solar tracking system which allows the reflectors to be rotated only around an axis. The law of motion of reflectors is the following [8]: (1) In Eq. (1), β represents the angle between the normal of the reflector and the horizontal direction East; d is the distance of the reflector from the center of the plant; h is the height of the tube from the plane of the mirrors; a and α are the azimuth and the solar altitude respectively.…”

Section: Figure 1 End Lossesmentioning

confidence: 99%

“…The electrical equations to the meshes, Eq. 7and (8), indicate that the supply voltage is distributed in: inductive voltage drop on the winding, voltage drop caused by the resistance of the electric circuit and induced electromotive force which generates the torque that allows rotor rotation. Eq.…”

Section: Table 1 Current Alternation In Phasesmentioning

confidence: 99%

“…These include losses due to blocking, shading, for extremes and for the error in the non-continuous motion that is followed. Losses due to blocking and shading can be reduced by increasing the distance between adjacent reflectors [8]. However, this solution limits the area actually occupied by the plant.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Solar Tracking System for a Linear Fresnel Plant with Two Degrees of Freedom Reflectors

Cucumo¹,

Ferraro²,

Kaliakatsos³

et al. 2019

IJES

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The mirrors of a traditional Fresnel system are moved with a tracking system that allows rotation around a single axis. However, this type of movement in the LFR generates high losses at its ends. The paper aims to study a configuration in which the primary reflectors that generate the aforementioned losses are made movable around two axes to increase the efficiency of the plant. The work presents the kinematic system for moving the field of mirrors in which the control of solar tracking is carried out with the open loop technique. From a constructive point of view, the mechanical components necessary for the purpose are identified. To allow a robust solar tracking, not influenced by external forces, the rotation of the mirrors is managed by "stepper" type servomotors. In particular, the use of the aforementioned motors generates a motion by steps, of which it is necessary to know in detail the temporal characteristics and the driving logic of the motors. The behavior of the whole set of "electric motor-mechanical system" will be modeled numerically in order to define the control logic of the servomotor that allows the execution of the steps at the right moment, evaluating the torque and the errors in the motion. In fact, the adoption of too small pitches improves solar tracking but needs the presence of a complex reduction system, with numerous gear wheels, which requires too high torque values.

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Section: Figure 1 End Lossesmentioning

confidence: 99%

Section: Table 1 Current Alternation In Phasesmentioning

confidence: 99%

See 1 more Smart Citation

Solar Tracking System for a Linear Fresnel Plant with Two Degrees of Freedom Reflectors

Cucumo¹,

Ferraro²,

Kaliakatsos³

et al. 2019

IJES

Self Cite

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show abstract

“…These include losses due to blocking, shading, for extremes and for the error in the non-continuous motion that is followed. Losses due to blocking and shading can be reduced by increasing the distance between adjacent reflectors [9]. Cosine losses can be reduced, for example with the translation of reflectors [10].…”

Section: Introductionmentioning

confidence: 99%

Study of Kinematic System for Solar Tracking of a Linear Fresnel Plant to Reduce End Losses

Cucumo¹,

Ferraro²,

Kaliakatsos³

et al. 2019

EJEE

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Linear Fresnel Plants are composed of flat mirrors that reflect direct radiation towards a fixed receiver tube parallel to the reflectors. In traditional plants, mirrors are able to rotate around a single axis. This type of solar tracking system generates high losses at its ends. In the paper a new configuration is studied in which the mirrors placed at the ends are moved around two axes. The proposed system is thus able to recover the direct radiation which, otherwise, would not reach the receiver tube. The rotation of the mirrors is managed by stepper servomotors. They allow a robust solar tracking, not influenced by external forces. The work presents the kinematic system for moving the field of mirrors actuated with open loop control. Stepper motors generate a motion by steps; in order to execute each step at the exact moment, the logic of movement is properly defined. It is necessary to know in detail the temporal position and the law of motion for each rotation to identify the driving logic of the motors. The behaviour of the "electric motor-mechanical system" is numerically modelled, evaluating the torque and the errors in the motion.

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“…Several studies have conducted in this field to simulate and optimize the heat transfer, the heat loss between the heat transfer fluid (HTF) and the absorber, which usually made from pipe, rectangular or trapezoidal duct. Other studies investigated the effect of shading and blocking between mirrors and the thermal efficiency [6][7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation and exergy analysis of an air heater with a solar concentrator used for drying processes

Karoua¹,

Moummi²,

Hamidat³

et al. 2018

IJHT

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In this paper, a solar air heater collector is developed and investigated. A concentrating feature of Linear Fresnel Reflector and the characteristics of flat plate air heaters (LFRAH) collectors are used. In this experimental study, three configurations of the absorber used to improve the thermal performance of LFRAH for the drying and the space heating processes, where two configurations of the absorber plate have different types of artificial roughness and the third configuration has a smooth absorber. The measured parameters are the ambient temperature, inlet and outlet temperatures of the air heater, the temperatures of the absorber, and the solar radiation intensity. The measurements performed at the same values of mass flow rate, 0.018 (kg.s -1 ). The introduction of the artificial roughness at the absorber plate allows having average air temperatures greater than 100° C. The comparison of the thermal efficiency shows that the roughened absorbers improve the thermal efficiency by 62% compared to the smooth absorber.

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Law of motion of reflectors for a linear Fresnel plant

Cited by 11 publications

References 6 publications

Solar Tracking System for a Linear Fresnel Plant with Two Degrees of Freedom Reflectors

Solar Tracking System for a Linear Fresnel Plant with Two Degrees of Freedom Reflectors

Study of Kinematic System for Solar Tracking of a Linear Fresnel Plant to Reduce End Losses

Experimental investigation and exergy analysis of an air heater with a solar concentrator used for drying processes

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