Investigating the effects of geometry in solar thermal absorber plates with micro-channels

Oyinlola, Muyiwa; Shire, G. S. F.; Moss, R.W.

doi:10.1016/j.ijheatmasstransfer.2015.06.087

Cited by 13 publications

(6 citation statements)

References 41 publications

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“…The results showed that thermal improvement can be achieved by increasing the fluid velocity. The results are beneficial for the design of micro-channel absorber plates [14].…”

Section: Introductionmentioning

confidence: 92%

Absorber Thickness Effect on The Effectiveness of Solar Collectors to Production Hot Air For Drying

Syuhada

Maulana

2018

E3S Web Conf.

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One way to increase the drying rate using a solar collector is to increase the air temperature of the collector and the time of circulation of hot air delivered to the drying chamber. The optimization of heat absorber by utilizing solar energy has been shown to be strongly influence by fluid flow characteristics in the collector channel. This study examined the sharp turning channel on the air passage of a solar collector. Collector size used was 305 cm x 80 cm and had 10 sharp turning channel baffles. Solar radiation absorbent material used in this collector test is iron sand with three thickness variations, namely 3, 6, and 9 cm. The measurement results show that the air temperature that can be produced by the collector with a thickness of 3 cm absorber reaches 85 degree Celsius with an effective drying time of 8 hours and the final air temperature testing on the collector out side still reaches about 40 degree Celsius at air temperature of 32 degree Celsius. At a thickness of 6 cm absorber, the air temperature inside the collector was about 83 degrees and the duration of 10 hours of drying time, with the collector-out air temperature around 39 degree Celsius at the air temperature of 30 degree Celsius. In contrast to the 9 cm thickness of the absorber, the drying air temperature was only 81 degree Celsius and the drying time was 12 hours and the final air temperature measurement was 40 degree Celsius at the ambient temperature was 27 degree Celsius. This result can be seen as the effect of thick collector absorber on solar thermal energy that can also be absorbed by absorber solar collector.

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“…The results showed that thermal improvement can be achieved by increasing the fluid velocity. The results are beneficial for the design of micro-channel absorber plates [14].…”

Section: Introductionmentioning

confidence: 92%

Absorber Thickness Effect on The Effectiveness of Solar Collectors to Production Hot Air For Drying

Syuhada

Maulana

2018

E3S Web Conf.

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“…They concluded that the multi V-shaped ribs with gap is the most effective roughness style which offers higher heat transfer enhancement and lower pressure drop in heat transfer flow. Oyinlola et al [121] experimentally investigated the effects of micro channel geometry on the absorber of a compact flat plate solar collector. From the results, the authors stated that considerable improvements in thermal performance can be achieved by increasing the fluid velocity with a corresponding increase in pumping power input.…”

Section: Advances In Solar Receiversmentioning

confidence: 99%

Technological Advances to Maximize Solar Collector Energy Output: A Review

Salvi

Bhalla

Taylor

et al. 2018

Journal of Electronic Packaging

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Since it is highly correlated with quality of life, the demand for energy continues to increase as the global population grows and modernizes. Although there has been significant impetus to move away from reliance on fossil fuels for decades (e.g., localized pollution and climate change), solar energy has only recently taken on a non-negligible role in the global production of energy. The photovoltaics (PV) industry has many of the same electronics packaging challenges as the semiconductor industry, because in both cases, high temperatures lead to lowering of the system performance. Also, there are several technologies, which can harvest solar energy solely as heat. Advances in these technologies (e.g., solar selective coatings, design optimizations, and improvement in materials) have also kept the solar thermal market growing in recent years (albeit not nearly as rapidly as PV). This paper presents a review on how heat is managed in solar thermal and PV systems, with a focus on the recent developments for technologies, which can harvest heat to meet global energy demands. It also briefs about possible ways to resolve the challenges or difficulties existing in solar collectors like solar selectivity, thermal stability, etc. As a key enabling technology for reducing radiation heat losses in these devices, the focus of this paper is to discuss the ongoing advances in solar selective coatings and working fluids, which could potentially be used in tandem to filter out or recover the heat that is wasted from PVs. Among the reviewed solar selective coatings, recent advances in selective coating categories like dielectric-metal-dielectric (DMD), multilayered, and cermet-based coatings are considered. In addition, the effects of characteristic changes in glazing, absorber geometry, and solar tracking systems on the performance of solar collectors are also reviewed. A discussion of how these fundamental technological advances could be incorporated with PVs is included as well.

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“…Figure 2 shows the thermocouple arrangement on the absorber plate. A comprehensive description of the experimental setup is presented in [19], [32]. Table 2 shows how various parameters were estimated from the experiments …”

Section: Description Of Experimental Setupmentioning

confidence: 99%

“…A comprehensive description of the experimental setup is presented in literature. 19,33 Table 2 shows how various parameters were estimated from the experiments. The micro-channel plate has fluid passing along rectangular passages, the fourth side of the passage is formed by a cover plate that is clamped in place hard against the inter-passage ribs, and the plate has a total thickness .…”

Section: Description Of Experimental Setupmentioning

confidence: 99%

Characterising micro-channel absorber plates for building integrated solar thermal collectors

Oyinlola

Shire

2018

Building Services Engineering Research and Technology

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Abstract.This paper discusses the characterisation of micro-channel absorber plates for Compact Flat Plate solar thermal collectors. Experimental and computational studies were carried out at typical operating conditions for flat plate solar collectors; overall heat loss coefficient in the range 2 -8 W/m 2 .°C, flow rate in the range 0.01 -0.1 kg/s/m 2 and heat transfer coefficients in the range 100 -1000 W/m 2 .°C. Three Dimensional numerical analysis using commercial CFD package, Ansys CFX, showed that heat transfer occurred on only three surfaces of the channel and there was a peripheral variation of the heat flux density. It was also observed that axial thermal conduction could modify the surface boundary at the inlet and outlet, however, the middle section of the channel could be approximated as a rectangular channel with three walls transferring heat under a H1 boundary condition. Experimental studies were used to estimate the standard parameters (channel efficiency, F, collector efficiency factor, F', heat removal factor, FR, and flow factor F") for predicting performance of the flat plate collectors. An alternate parameter, channel efficiency, F, was proposed to replace Fin efficiency, F, used in standard collector analysis. The results showed that values of F and F', very close to unity could be achieved with this design when the overall heat loss coefficient is below 2 W/m 2 .°C. The analysis further revealed that increasing the fluid-plate heat transfer coefficient beyond 300 W/m 2 .°C has marginal effect on the collector efficiency factor at a given UL value. The collector flow factor F" and the heat removal factor could be improved by increasing the collector capacitance rate; this can be achieved by increasing the mass flow rate per collector area ̇/ , as well as reducing the overall heat loss, UL . This analysis is important for optimizing design and operating parameters, especially to minimize temperature gradient in the transverse and longitudinal directions.

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Investigating the effects of geometry in solar thermal absorber plates with micro-channels

Cited by 13 publications

References 41 publications

Absorber Thickness Effect on The Effectiveness of Solar Collectors to Production Hot Air For Drying

Absorber Thickness Effect on The Effectiveness of Solar Collectors to Production Hot Air For Drying

Technological Advances to Maximize Solar Collector Energy Output: A Review

Characterising micro-channel absorber plates for building integrated solar thermal collectors

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