Simulation study on the efficiency of thermochromic absorber coatings for solar thermal flat-plate collectors

Müller, Sebastian; Giovannetti, Federico; Reineke‐Koch, Rolf; Kastner, Oliver; Hafner, Bernd

doi:10.1016/j.solener.2019.06.064

Cited by 34 publications

(10 citation statements)

References 28 publications

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“…Researchers need to determine which are the best absorber coating or insulation material for the collector. Müller et al [32] conducted a test on three selected absorber coatings: black chrome; highly selective sputtered PVD coatings; and solar paints. The aims were to investigate the thermal performance and the stagnation behavior of FPSC with the coatings and compared them with the standard.…”

Section: Absorber Coatingsmentioning

confidence: 99%

“…The results also showed that absorber coating can enhance thermal performance and reduce the risk of collector overheating during stagnation period, i.e., summer. By selecting a coating that has higher emittance or lower absorptance at a higher temperature, it will reduce the maximum temperature of the collector and significantly prevent stagnation temperature [32]. As the temperature increases, the coating with lower absorptance will increase thermal resistance and slow down solar absorption, hence reducing the time to reach stagnation temperature.…”

Section: Absorber Coatingsmentioning

confidence: 99%

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Thermal Performance Enhancement in Flat Plate Solar Collector Solar Water Heater: A Review

et al. 2020

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Various studies to improve the thermal performance of flat plate solar collector (FPSC) solar water heater have been conducted, and more are currently in progress. This study aims to review existing methods on thermal performance enhancement for FPSC and discuss on heat-transfer enhancement using vibration and its potential application for FPSC. Ten methods for improving thermal performance are identified, which include applications of nanofluids, absorber coatings, phase change materials (PCM), thermal performance enhancers, FPSC design modifications, polymer materials, heat loss reduction, mini and micro channel and heat-transfer enhancement using vibration. An examination of heat-transfer enhancement using vibration in low frequency ranges for an evacuated-tube solar collector (ETSC) solar water heater system showed that it can potentially achieve heat-transfer enhancement of up to 78%. Nevertheless, there is still a lack of research on the applications of heat-transfer enhancement using vibration on FPSC to date.

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Section: Absorber Coatingsmentioning

confidence: 99%

Section: Absorber Coatingsmentioning

confidence: 99%

Thermal Performance Enhancement in Flat Plate Solar Collector Solar Water Heater: A Review

et al. 2020

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“…It was noticed that compared to PVD sputter coatings, the auxiliary energy demand was improved by 6%, 7%, and 21% when the absorber plate was coated with black chromium, thermochromic, and solar paint coatings, respectively. In relation to the stagnant temperature estimated for PVD coatings, there was a corresponding reduction of 5.71%, 17.14%, and 22.85% for black chromium, thermochromic and solar paint coatings, respectively (Müller et al, 2019). A 3D transient CFD model was proposed to determine the effect of PCM along with the fins.…”

Section: Introductionmentioning

confidence: 99%

Rheological Behavior of Air in the Two-Pass Solar Collector

Dhaundiyal

2022

Front. Energy Res.

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This study pivoted on the flow behavior of air streams across solar air collectors provided with wooden baffles under the absorber plates. The two-pass system was used for both flat and finned surfaces. The von Kármán momentum integral and Blasius equations were solved with the help of PDPE and ODE45 techniques. The solution was assumed to be a part of the initial value problem (IVP). The energy analysis of both solar air collectors was carried out using the Hottel–Whillier–Bliss equation (HWB) equation. The Sankey diagram was used for energy distribution across the solar collectors. The gray box modeling approach was adopted to comprehend the airflow behavior across the channel. The objective of this study is to examine the intrinsic behavior of the proposed design. The displacement of boundary to compensate for the momentum of air stream (θt) decreased by 31.25%–62.50% with an increase in mass flow rate (m)˙of 24.69%–49.38% for the flat plate collector (FPC). Similarly, the shear stress posed by the absorber plate (τw) dropped by 15.89%–37.20% with the augmentation of the mass flow rate. The momentum thickness for the flat plate with triangular fin (FPTF) increased relatively by 31.25%, compared to FPC at 8.10 g·s−1. The estimated value of collector efficiency (ηI) FPTF soared up by 4%–11.51% when it was juxtaposed against the corresponding values derived for FPC. The wall shear stress near the absorber plate followed that of a second-order Gaussian model. It was noticed in this study that the addition of the fin slowed down the shear effect and the momentum defect of airstream at the same mass flow rate.

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“…Beyond numerous physical alterations, a variety of selective coatings have also been employed to improve the efficiency of solar water heating systems. To prevent overheating, Muller employed thermochromic selective coatings 18 . E. Alshamalieh combined Ni‐Al alloy and black paint for efficiency enhancement 19 .…”

Section: Introductionmentioning

confidence: 99%

Thermal application of composites of iron and magnesium in thermosyphon solar water heating system

et al. 2021

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A novel and low‐cost mixture of iron and magnesium have been synthesized and used as selective coatings for flat plate absorber in solar water heating system. The commercial black paint is fabricated with the mixture of composition Fe3(PO4)2·0.1Mg2P2O7·1.9 MgSO4(FPM3A). The composition of the coating mixture has been characterized by various analytical techniques. Thermal studies of these mixtures were accomplished using differential scanning calorimetry and thermo‐gravimetric analysis. From the thermal analysis, it has been observed that the mixtures can be used as thermal heat storage materials. The FPM3A‐modified black paint has been tested in a thermosyphon solar water heater prototype. The average water temperature and efficiency of the flat plate absorber with FPM3A‐modified black paint have increased by an average of 7.5° and around 12%, respectively, in comparison with that with commercial unprocessed black paint.

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Simulation study on the efficiency of thermochromic absorber coatings for solar thermal flat-plate collectors

Cited by 34 publications

References 28 publications

Thermal Performance Enhancement in Flat Plate Solar Collector Solar Water Heater: A Review

Thermal Performance Enhancement in Flat Plate Solar Collector Solar Water Heater: A Review

Rheological Behavior of Air in the Two-Pass Solar Collector

Thermal application of composites of iron and magnesium in thermosyphon solar water heating system

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