Solar air heaters: Design configurations, improvement methods and applications – A detailed review

Kabeel, A.E.; Hamed, Mofreh H.; Omara, Z.M.; Kandeal, A.W.

doi:10.1016/j.rser.2016.12.021

Cited by 168 publications

(66 citation statements)

References 68 publications

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“…Kabeel et al . and Alta et al . reported that baffles improve the heat transfer between the absorbed and flowing air, and reduce irreversibility.…”

Section: Methodsmentioning

confidence: 89%

“…Inside the SAH, five glass baffles were placed ( Figure 1a) to obtain a winding pathway of air when operational. Kabeel et al [21] and Alta et al [25] reported that baffles improve the heat transfer between the absorbed and flowing air, and reduce irreversibility. Baffles also alter the flow patterns and cause turbulence in the heated surface [19].…”

Section: Description Of the Solar Systemmentioning

confidence: 99%

“…SAHs are typically absorber plates that receive solar irradiation and create passages for the flowing air; thus naturally increasing the temperature of the air. They are easy and cheap to fabricate, involving a glass cover as a roof along with insulation at the bottom and sides to avoid heat losses [21]. Varun et al [22] used solar dryer integrated with SAH to improve the performance of solar drying for agricultural products.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of the solar brine evaporation process: Introduction of a solar air heater

Poblete

Salihoğlu

2018

Env Prog and Sustain Energy

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The purpose of this study was to investigate the evaporation process of reject brine by using a solar system. The solar system contained a solar still coupled with a solar air heater (SAH). Solar still had a heated base, which was connected to the solar collector with a copper pipe. The influence of the introduction of the SAH to the system and increased levels of air mass flowrates was investigated. Variations in temperature and solar irradiation were monitored as well as brine evaporation. Introducing the SAH and increasing the air mass flowrate resulted in faster brine evaporation, higher utilization rate of solar radiation, higher brine, and base temperature levels within the solar still compared to the system without the SAH. The mean base temperature of the system with the SAH was 43.46 ± 11.3°C, while that of the system without the SAH was 30.62 ± 7.35°C. The use of the SAH and high air mass flowrates influenced the temperature distribution within the solar still, which affected the evaporation of the brine in a positive way. Introduction of the SAH and high air mass flowrate increased the drying efficiency of the solar system at a level of 120%. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13062, 2019

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“…Kabeel et al . and Alta et al . reported that baffles improve the heat transfer between the absorbed and flowing air, and reduce irreversibility.…”

Section: Methodsmentioning

confidence: 89%

Section: Description Of the Solar Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optimization of the solar brine evaporation process: Introduction of a solar air heater

Poblete

Salihoğlu

2018

Env Prog and Sustain Energy

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“…They have more advantageous than liquid heaters because the used fluid ,air, is not as freezable or stagnant as liquids and has no environmental or health hazards [1]. Moreover, SAHs have a simple construction of thermally insulated duct covered with glass cover.…”

Section: Introductionmentioning

confidence: 99%

Influence of bladed and glazed entrance on the performance of solar air heaters

et al. 2018

Self Cite

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The performance of a flat plate single-pass Solar Air Heater (SAH) modified at the entrance region was experimentally investigated. This entrance region was covered with glass cover instead of steel. Using glass at the entrance region increases the heating area exposed to solar radiation and avoids the restriction of solar radiation from reaching this area as in case of steel cover. Also, guide blades were placed in the entrance region to ensure well air distribution on the absorber surface and hence enhancing the thermal performance of SAH. The modified SAH was compared with another of conventional entrance. The experiments were performed at four air flow rates ranged from 0.013 to 0.04 kg/s. The modifications led to good enhancement in both the air temperature difference and the efficiency. For the daily efficiency, the maximum values are 43.43, 40.48 and 32.92 % for the glazed-bladed entrance SAH, glazed entrance SAH and conventional SAH, respectively, at the rate of 0.04 kg/s. The glazed-bladed SAH showed a good improvement in the daily thermal efficiency by 6.72 to 10.5 % over the conventional heater and by 2.16 to 3.25 % over the glazed SAH.

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“…Zheng et al [13] performed experimental investigation of solar air heaters having perforating corrugated plate, slit-perforated plate, and corrugated packing. In addition to this, a number of studies have been conducted, and they mainly focused on the performance improvement by artificially roughened rip mounted on the absorber plater or modified absorber structure [14][15][16][17].Another technique to increase the heat-transfer performance of solar air heater is modifying the air duct or the shape of bottom plate in an air channel of the solar air heater. Ho et al [18] analyzed the performance of double-pass cross-corrugated solar air collector that has the wavelike-shaped absorbing plate and bottom plate.…”

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confidence: 99%

CFD Analysis on the Heat Transfer and Fluid Flow of Solar Air Heater having Transverse Triangular Block at the Bottom of Air Duct

Choi

2020

Energies

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In this study, a two-dimensional CFD (computational fluid dynamics) analysis was performed to investigate the heat-transfer and fluid-friction characteristics in a solar air heater having a transverse triangular block at the bottom of the air duct. The Reynolds number, block height (e), pitch (P), and length (l) were chosen as design parameters. The results are validated by comparing the Nusselt number predicted by simulation with available experimental results. Renormalization-group (RNG) k-ε model with enhanced wall-treatment was selected as the most appropriate turbulence model. From the results, it was found that the presence of a transverse triangular block produces a higher Nusselt number than that of smooth air duct. The enhancement in Nusselt number varied from 1.19 to 3.37, according to the geometric conditions investigated. However, the use of transverse triangular block also results in significantly higher friction losses. The thermohydraulic performance (THPP) was also estimated and has a maximum value of 1.001 for height (e) of 20 mm, length (l) of 120 mm, and pitch (P) of 150 mm, at Reynolds number of 8000. Furthermore, in the present study, correlations of the Nusselt number and friction factor were developed as a function of geometrical conditions of the transverse triangular block and Reynolds number, which can be used to predict the value of Nusselt number and friction factor with the absolute percentage deviations of 3.29% and 7.92%, respectively. solar air heater having non-uniform cross-section transverse rib roughness on the absorber plate. Akpinal and Koçyiǧit [7] analyzed the performance of a solar air heater supplied with various obstacles experimentally. Singh et al. [8] evaluated the effect of multiple arc-shaped ribs on the heat-transfer and friction characteristics, with various geometrical parameters. Singh et al. [9] investigated the heat and fluid-flow characteristics in a rectangular duct roughened with periodic discrete V-down rip. Kumar and Kim conducted a CFD-based analysis to investigate heat transfer and friction characteristics in rectangular channel with discrete multi-V-pattern ribs [10].The other method to improve the performance of a solar air heater is modifying the absorber plate. Karim and Hawlader [11] examined the performance of three types of solar air collectors having a flat-plate, v-corrugated, and finned absorber. Ho et al. [12] conducted an experimental and theoretical analysis of the double-pass cross-corrugated and double-pass V-corrugated solar air collector. Zheng et al. [13] performed experimental investigation of solar air heaters having perforating corrugated plate, slit-perforated plate, and corrugated packing. In addition to this, a number of studies have been conducted, and they mainly focused on the performance improvement by artificially roughened rip mounted on the absorber plater or modified absorber structure [14][15][16][17].Another technique to increase the heat-transfer performance of solar air heater is modifying the air duct or the shape ...

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Solar air heaters: Design configurations, improvement methods and applications – A detailed review

Cited by 168 publications

References 68 publications

Optimization of the solar brine evaporation process: Introduction of a solar air heater

Optimization of the solar brine evaporation process: Introduction of a solar air heater

Influence of bladed and glazed entrance on the performance of solar air heaters

CFD Analysis on the Heat Transfer and Fluid Flow of Solar Air Heater having Transverse Triangular Block at the Bottom of Air Duct

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