A numerical study of the double-glazed solar air heater (DG-SAH) performance using optimized gas-filled interspaces

Bennour, Fethi; Mzad, Hocine

doi:10.1016/j.csite.2022.102492

Cited by 10 publications

(6 citation statements)

References 25 publications

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“…">The pressure drop increases with the width‐to‐height ratio augmentation. The Eismann correlation agrees well with the literature 23,31,33,47 …”

Section: Discussionsupporting

confidence: 90%

“…The Eismann correlation agrees well with the literature. 23,31,33,47 The optimal gap between the glasses, within [10][11][12][13] mm, led to more accurate results than those of Holland's correlation. 6.…”

Section: Discussionmentioning

confidence: 92%

“…Several studies have been performed using both energy and exergy analysis to obtain the thermal efficiencies of flat plate solar systems. Bennour and Mzad 23 performed a numerical study on the thermal performance improvement of a double‐glazed solar air heater (DG‐SAH) using optimized gas‐filled interspaces. Air was replaced by noble gases (argon, xenon, krypton, and SF6) within the double‐glazing and between the inner glass and the absorber.…”

Section: Introductionmentioning

confidence: 99%

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On the effect of the transversal aspect ratio on the double‐glazed solar air heater performance

Mzad

Bennour

2023

Heat Trans

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The transversal aspect ratio of solar air heaters (SAHs) is a critical geometric parameter that influences the heat transfer from the absorber plate to the working fluid and, accordingly, the overall heat loss level. The present work addresses the effect of the aspect ratio on the performance of a solar air heating system and the behavior of heat transfer coefficients (HTCs) within it and along the flow channel. A mathematical model of energy‐balance equations was formulated to examine and analyze the double‐glazed solar air heater thermal behavior. The Eismann correlation, which is more accurate than Holland's correlation, was employed to determine the HTC between the two glass covers. The useful energy, Nusselt number (Nu), efficiency, overall loss, and HTCs as a function of the aspect ratio were evaluated across the collector length. On the basis of the findings, the higher the ratio, the better the efficiency of the SAH. Indeed, increasing the collector's cross‐sectional aspect ratio (r) up to 19 increases useful energy efficiency by more than 87%, Nu by 84%, thermohydraulic efficiency from 0.4 to 0.76, and overall heat loss by 1.15 W/(m2 K). Furthermore, reducing r from 19 to 2 will improve the collector power from 1.855 to 3.473 kW.

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“…">The pressure drop increases with the width‐to‐height ratio augmentation. The Eismann correlation agrees well with the literature 23,31,33,47 …”

Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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On the effect of the transversal aspect ratio on the double‐glazed solar air heater performance

Mzad

Bennour

2023

Heat Trans

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“…The heat collector technology utilizing solar radiation heat has significant potential for drying agricultural products (Fterich et al, 2018;Mahapatra and Tripathy 2019). Given the abundance of solar energy and its accessibility to all, collector technology emerges as a viable alternative for harnessing solar energy effectively, while mitigating pollution concerns (Chen et al, 2021;Fterich et al, 2018;Krishnananth and Kalidasa 2013), free to use (Bennour and Mzad 2022), energy sustainability (Zhou et al, 2023;Borzuei et al, 2021), and the energy demand continues to increase every year (Mokhlif et al, 2021). This type of technology has long been utilized and continues to change to improve the work efficiency of the collector itself.…”

Section: Introductionmentioning

confidence: 99%

“…It has two roles, namely as a trap and as a heat retainer under solar lighting. The air trapped between two glazes provides an insulating effect called an air insulator (Bennour Mzad 2022). This air insulator effect does not occur in single glazing.…”

Section: Introductionmentioning

confidence: 99%

Employing a Combination of a Double-Glazed Flat Solar Collector and Sensible Heat Storage for Drying Agricultural Products

Efendi,

Hendrawan,

Hawa

et al. 2024

Ecol. Eng. Environ. Technol.

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Convection heat collector technology is a promising technology for drying agricultural products. The study aimed to determine the temperature characteristics, energy efficiency, and thermal discharging of a flat plate-type collector using double-glazing technology integrated with heat storage material in the state of iron scraps in passive and active modes. Investigation was conducted for seven hours of exposure under the sun (08:00-15:00 local time). Ten temperature sensors and four humidity sensors were used during measurements to determine the thermal characteristics of the heat collector. The density of iron scraps as heat storage material is 250 kg/m 3 with an irradiation time of seven hours. The results indicate that the passive mode of operation has a higher temperature characteristics than the active mode. During irradiation process, the highest temperatures on the absorber in active and passive modes were 63 °C and 55 °C, respectively. Meanwhile, the highest temperatures on the TES in passive and active modes during irradiation were 55.6 °C and 50.6 °C, respectively. The energy efficiency of the collector ranges from 23.3-55.1% (passive) and 18.6-40.7% (active). The energy efficiency of the TES (Thermal Energy Storage) has a range of 7.4-22.7% (passive) and 7.4-13.0% (active). During discharging process, it shows that the TES in passive mode can store heat for 275 minutes and active mode for 95 minutes. Heat collectors that used double glazing technology and heat storage materials using iron scraps with a density of 250 kg/m 3 have a significant potential to extend the drying duration of agricultural products with limited exposure to sunlight and environmentally friendly heat collectors.

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A simple graphical method for sizing flat‐plate solar air heaters based on transversal and longitudinal aspect ratios

Mzad,

Bennour

2024

Heat Trans

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Solar air heaters (SAHs) are widely used for drying vegetables and fruits or for domestic heating. Certain sizing parameters are necessary to obtain the right dimensions for the required air temperature, flow rate, and thus useful thermal energy. The well‐known Hottel–Whillier–Bliss equation was used and made dimensionless by applying the collector longitudinal and transversal aspect ratios (rl and rt) of a double‐glazed flat plate solar air heater (DG‐FPSAH). The steady‐state equations are solved to determine the average temperatures. Thereafter, one could calculate the overall loss heat coefficient and efficiency factor, obtained analytically. A Matlab code was developed to estimate primarily unknown temperatures, useful energy, and the Nusselt number. An iterative numerical method is used until convergence occurs. The inlet cross‐sectional area and air flow velocity are defined as input data. The proposed sizing method depends on the output temperature required by the customer. This temperature can be determined from the plotted curves of the dimensionless ratios. Hence, the SAH‐needed dimensions are determined graphically depending on the functional requirements for construction planning, such as technology choice, work breakdown, and budgeting. In the present case study, based on the input parameters, an airflow rate of 1.2 kg/s entering a DG‐FPSAH with an output temperature of 41.5°C yields the dimensions of Lin = 3.824 m, Win = 2.735 m, and Hin = 0.1825, specifying the collector length, width, and air duct height. The gathered energy and thermohydraulic efficiency are: Qu = 7.91 kW, ηcol = 0.752, respectively.

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A numerical study of the double-glazed solar air heater (DG-SAH) performance using optimized gas-filled interspaces

Cited by 10 publications

References 25 publications

On the effect of the transversal aspect ratio on the double‐glazed solar air heater performance

On the effect of the transversal aspect ratio on the double‐glazed solar air heater performance

Employing a Combination of a Double-Glazed Flat Solar Collector and Sensible Heat Storage for Drying Agricultural Products

A simple graphical method for sizing flat‐plate solar air heaters based on transversal and longitudinal aspect ratios

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