A thermal model to investigate the power output of solar array for stratospheric balloons in real environment

Kayhan, Öznur

doi:10.1016/j.applthermaleng.2018.04.117

Cited by 19 publications

(11 citation statements)

References 23 publications

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“…It is of much interest to develop reliable models to predict T pv , and the PV performance, through prediction of the power output P m (t), when the module operates under any configuration and field conditions. Various mathematical expressions have been proposed and validated on their reliability to predict steady state T pv [1][2][3][4][5][6][7][8][9], as to be discussed in detail later in this paper or transient T pv profiles, [10][11][12][13][14] with good accuracy under any field conditions and for Building Integrated Photovoltaic (BIPV) configurations [15][16][17][18][19]. Those T pv prediction models are grouped in: explicit models described in [1][2][3][4][5][6][7], usually physics based theoretical models which try to incorporate the environmental parameters, mainly, solar irradiance on the PV plane I T , wind velocity v w , wind direction, heat transfer from the PV to the environment, and radiation exchanges between PV and environment: a.…”

Section: Introductionmentioning

confidence: 99%

A New Dynamic Model to Predict Transient and Steady State PV Temperatures Taking into Account the Environmental Conditions

Kaplanis

Kaplani

2018

Energies

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Photovoltaic (PV) cell and module temperature profiles, T c and T pv , respectively, developed under solar irradiance were predicted and measured both at transient and steady state conditions. The predicted and measured T c or T pv covered both a bare c-Si PV cell, by SOLARTEC, at laboratory conditions using a solar light simulator, as well as various c-Si and pc-Si modules (SM55, Bioenergy 195W, Energy Solutions 125W) operating in field conditions. The time constants, τ, of the T c and T pv profiles were determined by the proposed model and calculated using the experimentally obtained profiles for both the bare PV cell and PV modules. For model validation, the predicted steady state and transient temperature profiles were compared with experimental ones and also with those generated from other models. The effect of the ambient temperature, T a , wind speed, v w , and the solar irradiance, I T , on the model performance, as well as of the mounting geometries, was investigated and incorporated in the prediction model. The predicted temperatures had the best matching to the measured ones in comparison to those from six other models. The model developed is applicable to any geographical site and environmental conditions. Energies 2019, 12, 2 2 of 17 b.Theoretical based semi-empirical models, a mixture of Physics based processes elaborated on implicit functions, which through regression analysis incorporate the environmental conditions and develop expressions to predict T pv including geometrical factors like PV module inclination, sun-tracking systems, BIPV [6,8,21]. c.Approaches based on Artificial Neural Networks (ANN) [5,10,22].An assessment of the T pv prediction models discloses that those which have incorporated the radiation exchanges and the air flow regimes, where heat extraction off the modules is affected specifically, provide values closer to the measured ones [6,7,[23][24][25]. A comparison among the models is necessary as to conclude on the conditions T pv is predicted effectively and consistently. It is, therefore, necessary to compare T pv models extensively to examine their validity in any PV configuration as the ones studied in [20,[26][27][28][29].A time dependent temperature profile is developed in a PV cell when under solar irradiance, I T , [8,30]. The latter is the main factor contributing to the development of the temperature profile in which the ambient temperature T a and the wind speed play a role too. This profile has a straight relationship with I T at low Concentration Ratio, C, conditions, with C < 4, where C = I T /10 3 W/m 2 , and a strong dependence on the wind speed, v w ; that is, T c (t; I T , v w ). T c (t) depends, also, on the cell structure and the material composition of its layers. Figure 1 shows a section of a PV cell with its characteristic layers which govern the heat conduction causing an effect on the time constant, τ, of the temperature profiles. T c (t) or T pv (t), either the PV module is heated or cooled due to changes in the environmental conditions, is described ...

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Section: Introductionmentioning

confidence: 99%

A New Dynamic Model to Predict Transient and Steady State PV Temperatures Taking into Account the Environmental Conditions

Kaplanis

Kaplani

2018

Energies

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“…As seen in Figure 10, when relative velocity is 25 m/s, required thrust power obtained over 1000 kW. This amount of power can be supplied for a balloon using photovoltaic panel (Kayhan, 2018;Wang et al, 2007) and lightweight electric motors (Kongl et al, 2012).…”

Section: Numerical Resultsmentioning

confidence: 99%

Station Keeping of Wind Driven Stratospheric Balloon via Propulsion Unit

Kayhan

2020

Mühendislik Bilimleri Ve Tasarım Dergisi

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One of the most difficult problems in stratospheric balloon's design is to keep the balloon's geographic coordinates. Stratospheric wind speeds vary significantly both daily and throughout the year. Wind drag acting on the balloon should be manipulated to control the horizontal coordinates (longitude and latitude degree) of the stratospheric balloons. In this paper, propulsion unit is applied to a wind driven stratospheric balloon to keep balloon's coordinate over flight area. The simulation was applied to a zero-pressure high altitude balloon using actual wind profile for the first time to control the horizontal movement of the balloon. In addition, required thrust power and some parameters effects on it have been investigated. The results indicate that propulsion unit would be helpful to manipulate the horizontal motion of the balloon and to achieve keeping the balloon's geographic location.

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“…Fundamentally, the glass layer is tempered (to increase the mechanical strength of the module), highly transparent, low iron content and has a textured upper-surface (to reduce the solar irradiance reflection and absorption losses). The back layer is usually made of tedlar polymer that is functioning as irradiance blocker and also providing moisture resistance [13]. Anti-reflection coating (ARC) layer is typically added to the PV layer for efficient light trapping (not shown in Figure 1) [14].…”

Section: Physical Structures Of Pv Modulesmentioning

confidence: 99%

“…These parameters have a different impact on the temperature value; therefore, some of them are essential to be considered when constructing the thermal model. Following is a list of these parameters [4,5,13,[18][19][20][21][22][23].…”

Section: Parameters That Affect the Pv Module Thermal Behaviourmentioning

confidence: 99%

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A Novel Method for Thermal Modelling of Photovoltaic Modules/Cells under Varying Environmental Conditions

2020

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Temperature has a significant effect on the photovoltaic module output power and mechanical properties. Measuring the temperature for such a stacked layers structure is impractical to be carried out, especially when we talk about a high number of modules in power plants. This paper introduces a novel thermal model to estimate the temperature of the embedded electronic junction in modules/cells as well as their front and back surface temperatures. The novelty of this paper can be realized through different aspects. First, the model includes a novel coefficient, which we define as the forced convection adjustment coefficient to imitate the module tilt angle effect on the forced convection heat transfer mechanism. Second, the new combination of effective sub-models found in literature producing a unique and reliable method for estimating the temperature of the PV modules/cells by incorporating the new coefficient. In addition, the paper presents a comprehensive review of the existing PV thermal sub-models and the determination expressions of the related parameters, which all have been tested to find the best combination. The heat balance equation has been employed to construct the thermal model. The validation phase shows that the estimation of the module temperature has significantly improved by introducing the novel forced convection adjustment coefficient. Measurements of polycrystalline and amorphous modules have been used to verify the proposed model. Multiple error indication parameters have been used to validate the model and verify it by comparing the obtained results to those reported in recent and most accurate literature.

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A thermal model to investigate the power output of solar array for stratospheric balloons in real environment

Cited by 19 publications

References 23 publications

A New Dynamic Model to Predict Transient and Steady State PV Temperatures Taking into Account the Environmental Conditions

A New Dynamic Model to Predict Transient and Steady State PV Temperatures Taking into Account the Environmental Conditions

Station Keeping of Wind Driven Stratospheric Balloon via Propulsion Unit

A Novel Method for Thermal Modelling of Photovoltaic Modules/Cells under Varying Environmental Conditions

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