Experimental study of solar air heater performance by evacuated tubes connected in series and loaded with thermal storage material

Elbrashy, Amr; Abou-Taleb, F. Sh.; El-Fakharany, Magda K.; Essa, F.A.

doi:10.1016/j.est.2022.105266

Cited by 21 publications

(5 citation statements)

References 49 publications

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“…They created various types of ribs in the absorber plate and estimated turbulence imbalance and their performance improvement factor (Nu/f). In addition, other strategies such as multiple pass air flow, porous surface, fins arrangements and wavy micro-channel were also used for enhancing the solar heater performance [12,[14][15][16][17][18][19]. Many experimental and simulation studies on various roughened absorbing surface of solar air heating unit were presented in the literature [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Computational Analysis of Bulb-Shape Ribs Roughened Absorber Plate of Solar Air Heater

Mor,

Sikarwar,

Kumar

et al. 2024

Preprint

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In this work, thermo-hydrodynamic simulation was carried out for bulb-shaped ribs roughened absorbing surface of solar air heater at 1kW/m2 for and various Reynolds numbers. Primarily, sensitivity analysis of turbulent models was carried for flow over the surface, and it observed that RNG k-\(\epsilon\) model results is more closed with respect to Dittus-Boelter equation. After selection of appropriate turbulence model, simulations were carried out on a bulb-shape rib and other shapes of roughened ribs surface. This study reveals that absorber bulb shaped ribs roughened surface has at least two times more performance improvement factor (Nu/f) as compared to the other ribbed shape roughened surface. Eventually, the Nusselt number and Coefficient friction for bulb shaped ribs roughened surface were correlated in terms of Reynolds number (Re) and relative roughness (β). These correlations are substantial for designing solar air heating systems for bulb-shaped ribs roughened as absorbing surface.

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Section: Introductionmentioning

confidence: 99%

Computational Analysis of Bulb-Shape Ribs Roughened Absorber Plate of Solar Air Heater

Mor,

Sikarwar,

Kumar

et al. 2024

Preprint

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“…The LSS system for water and air heater generally uses low-temperature PCM, which mainly comes from fatty acid [14], hydrocarbon wax [15], and natural wax [16]. The low thermal response for the LSS tank is overcome by using solid additives [17], a high surface area heat exchanger [18], and nano-enhanced working fluid [19]. The effort allows for building a desirable LSS tank.…”

Section: Introductionmentioning

confidence: 99%

Charge Assessment for Nitrate-Based Salt as a Phase Change Material for a Medium-Temperature Latent Storage Tank

Ismail,

Widodo,

Rahman

2024

Latvian Journal of Physics and Technical Sciences

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The present study assesses the heat characteristic of the nitrate-salt mixture as a phase change material (PCM) for a medium-temperature latent storage system (LSS). Two binary and ternary mixtures are evaluated, which demonstrate different thermal behaviour. The highest melting and latent heat capacity is obtained by KNO3(0.4)/NaNO3(0.6) at 223.8 °C and 161.5 J/g. However, it has a higher supercooling degree with a partial phase transition between 217.6 °C and 251.5 °C, making it unfeasible for a medium-temperature LSS tank. The ternary mixture (TM) with NaNO2(0.4)/KNO2(0.53)/NaNO3(0.7) demonstrates a stable phase transition with minimum partial phase transition (22.1 °C) and suitable heat of fusion (98.1 J/g). Further evaluation through static thermal profiling demonstrates that the TM has a notable performance during solid-sensible charge with a charge level indicator (CLI) around 45.3 %–49.1 %. The TM can be charged up to 85.7 % until the end stage of the phase transition. It promotes a better storage capacity with suitable performance since the system can be charged effectively at a suitable temperature range (< 160 °C) for various applications. The micrograph observation indicates some dispersed particles and local agglomeration, which makes phase stabilization as an advantageous method to promote a stable phase change process. The TM can be considered a suitable PCM for a medium-temperature LSS tank that allows for a better solar thermal renewable system operation.

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“…The efficiency of helical inserts ET‐SAH and conventional ET‐SAH was 70.9% and 64.5%, respectively. Elbrashy et al, 13 investigated the performance of SAH. The system used five ETC which were connected in series.…”

Section: Introductionmentioning

confidence: 99%

Experimental comparison of solar air heater based on single and double‐ends open evacuated tube collector

Tiwari,

Kumar

2023

Env Prog and Sustain Energy

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The hot air has a lot of applications like drying, space heating, desiccant air conditioning and desalination, which attracts the attention of researchers towards the system used for producing the hot air. In the present work, two different solar air heaters that is, double‐ends open evacuated tube based solar air heater (system 1) and single‐end open evacuated tube based solar air heater (system 2) are proposed and compared experimentally. The aperture area of each system is 4.687 m2 and operated under same weather conditions. The experiments are performed at three different mass flow rates of the process air that is, 153.21, 207.94, and 246.24 kg/h. The highest mean air temperature difference is 62.91 and 48.8°C for system 1 and system 2 respectively at mass flow rate of 153.21 kg/h. The highest mean energy and exergy efficiency obtained by the system 1 and system 2 are 81.55%, 6.80%, and 65.45% and 4.25% respectively. The present work is also compared with the work presented in literature and it is observed that double‐end open evacuated tube collector has significantly high energy and exergy efficiency with higher hot air temperature.

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Experimental study of solar air heater performance by evacuated tubes connected in series and loaded with thermal storage material

Cited by 21 publications

References 49 publications

Computational Analysis of Bulb-Shape Ribs Roughened Absorber Plate of Solar Air Heater

Computational Analysis of Bulb-Shape Ribs Roughened Absorber Plate of Solar Air Heater

Charge Assessment for Nitrate-Based Salt as a Phase Change Material for a Medium-Temperature Latent Storage Tank

Experimental comparison of solar air heater based on single and double‐ends open evacuated tube collector

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