Experimental investigation of thermal performance of a double-flow solar air heater having aluminium cans

Özgen, Filiz; Esen, Mehmet; Esen, Hikmet

doi:10.1016/j.renene.2009.03.029

Cited by 322 publications

(101 citation statements)

References 19 publications

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“…The values of Reynolds number, Nusselt number, average Nusselt number, friction factor and thermal-hydraulic performance have been calculated using the following equations [15,17,[19][20][21][22][23]:…”

Section: Data Reductionmentioning

confidence: 99%

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Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Kumar

Kim

2016

Energies

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This article presents heat transfer and fluid flow characteristics in a solar air heater (SAH) channel with multi V-type perforated baffles. The flow passage has an aspect ratio of 10. The relative baffle height, relative pitch, relative baffle hole position, flow attack angle, and baffle open area ratio are 0.6, 8.0, 0.42, 60˝, and 12%, respectively. The Reynolds numbers considered in the study was in the range of 3000-10,000. The re-normalization group (RNG) k-ε turbulence model has been used for numerical analysis, and the optimum relative baffle width has been investigated considering relative baffle widths of 1.0-7.0.The numerical results are in good agreement with the experimental data for the range considered in the study. Multi V-type perforated baffles are shown to have better thermal performance as compared to other baffle shapes in a rectangular passage. The overall thermal hydraulic performance shows the maximum value at the relative baffle width of 5.0.

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Section: Data Reductionmentioning

confidence: 99%

“…Ozgen et al [17] investigated the thermal performance in a rectangular passage with a blockage attached to a heated wall. They reported that the collector efficiency could be improved by increasing the air velocity and the Nu data between the heated wall and the fluid.…”

Section: Introductionmentioning

confidence: 99%

Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Kumar

Kim

2016

Energies

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“…Tel örgü yapısı ile ısıl verimin konvansiyonel yapıdaki düz absorber plakalı güneş kollektörlerine kıyasla önemli bir ölçüde arttığını gözlemle-mişlerdir [7]. Çalışmalarda, hava akışına türbülans etkisi verecek engellerin absorber plaka üzerine yerleştirilmesi yoluyla da ısıl verimde önemli artışlar sağlandığı belirtilmiştir [8][9][10]. Esen, güneş enerjili hava kollektöründe absorber plakanın her iki yüzeyine de farklı şekillerdeki engelleri yerleştirerek enerji ve ekserji analizi yapmıştır.…”

Section: Gi̇ri̇ş (Introduction)unclassified

Yutucu Plaka Üzerine Konik Yayların Yerleştirildiği Güneş Enerjili Hava Kollektörünün Bulanık Mantık ile Modellenmesi

Abuşka¹,

Akgül²,

Altıntaş³

2017

Journal of Polytechnic

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Politeknik Dergisi, 2017; 20 (4) : 907-914 Journal of Polytechnic, 2017; 20 (4) ÖZGüneş enerjili hava kollektörleri (GEHK) genellikle mahal ısıtma ve tarımsal ürünlerin kurutulmasında kullanılmaktadır. GEHK'nde yutucu plaka ve akışkan arasındaki ısı transferinin düşük olmasından dolayı ısıl verimleri düşüktür. Bu çalışmada ısıl verimin yükseltilmesine yönelik olarak yeni bir yutucu plaka geometrisi tasarlanmış ve imal edilmiştir. Konik yayların çapraz sıralı olarak monte edildiği yutucu plakalı ve karşılaştırma amaçlı düz yutucu plakalı kolektörlerden ibaret test düzeneği kurulmuştur. Çapraz sıralı konik yaylarla yüzey alanının, akışkan ile yutucu plaka etkileşiminin ve türbülans etkisinin artırılarak termal verimin yükseltilmesi amaçlanmıştır. Sistemin performansı deneysel olarak test edilmiştir. Deneylerde havanın kollektöre giriş ve çıkış sıcaklıkları, global radyasyon, kollektörden havanın çıkış hızı, yutucu plaka sıcaklıkları, kollektör kasası dış yüzey sıcaklığı ve saydam örtü sıcaklıkları ölçülmüştür. Yapılan ölçümlere dayalı olarak ısıl verimi hesaplanmıştır. Elde edilen deneysel verilerle sistemin Bulanık Mantık modeli oluşturulmuş ve üç farklı üyelik fonksiyonuna (Üçgen-Gaussian-Trapez) göre giriş parametrelerine dayalı olarak havanın kollektörden çıkış sıcaklığı ve ısıl verim modellenmiştir. Sonuç olarak bulanık mantık ile üçgen üyelik fonksiyonuna göre yapılan modellemenin sıcaklık için % 96, termal verim için ise % 94-95 oranında deneysel verilerle uyumlu olduğu sonucu elde edilmiştir.Anahtar Kelimeler: Güneş enerjili hava kollektörü, konik yay, bulanık mantık, modelleme, çıkış sıcaklığı, termal verim. The Fuzzy Logic Modeling of Solar Air Heater HavingConical Springs Attached on the Absorber Plate ABSTRACT Solar air collectors (SAC) are usually used for space heating and drying of agricultural products. In SACs, thermal efficiency is low due to the low heat transfer between the absorber plate and fluid. In this study, a novel absorber plate geometry is designed and manufactured for enhancing the thermal efficiency. A comparative test system consisting of a flat absorber plate with staggered conical springs and a collector with flat absorber plate was established. It is aimed to increase the thermal efficiency by increasing the turbulence effect of the surface area, the interaction between the fluid and the absorber plate with the staggered conical springs. The performance of the systems was tested experimentally. In the experiments, inlet and outlet temperature of the collectors, global radiation, the exit velocity of air from the collectors, the absorber plate temperatures, backside surface temperature and transparent cover temperatures were measured. The thermal efficiency was calculated based on the measurements. Consisting of the fuzzy logic model of the system with the experimental data obtained, the outlet air temperature of the collector and thermal efficiency is modeled based on the input parameters according to three different membership functions (Triangle-Gaussian-Trapeze). As a re...

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“…The main drawback of a SAH is that the heat-transfer coefficient between the absorber plate and the air stream is low, which results in a lower thermal efficiency of the heater [14]. However, different Volume 4, Number 6, November 2014 modifications are suggested and applied to improve the heat-transfer coefficient between the absorber plate and air [15].…”

Section: Introductionmentioning

confidence: 99%

Reflectance, Transmittance and Absorptance of HDPE, LDPE, Glass and Sand Layer Used in a SAH

Ndegwa¹,

Ndiritu²,

Hussein³

et al. 2014

IJAPM

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Abstract:The total Infra-red (IR) transmission of polymer films is a very important property in engineering, which determines their suitability for a specific application at a given temperature level. Aiming to investigate the percentage IR transmission of two polymer material films and glass of a particular thickness, an analysis is developed for the comparative evaluation of this very important physical property. Sand is a solid and a poor conductor of heat. That means that when sunlight hits sand, all the energy of the sunlight is absorbed in the first millimeter or so of the sand, the heat stays there or spreads only a few millimeters down. So those few millimeters get quite hot. High transmittance and absorptance of top cover and absorber plate are among the factors that contribute to the high efficiency of a SAH. Transmission and reflection spectra were obtained from the Spectro 320 Optical Spectrum Analyzer. IR Radiation (IR) was obtained from a lamp and measurements made at room temperature and relative humidity of 21°C and 25%RH respectively. The study shows that the transmittance of clear HDPE, LDPE and glass are 0.84, 0.72 and 0.72 respectively at wavelengths 791.90, 735 .02 and 820.89nm. The absorptance of sand layers was found to be 56% and 59% for grey and brown sand respectively.

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Experimental investigation of thermal performance of a double-flow solar air heater having aluminium cans

Cited by 322 publications

References 19 publications

Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Yutucu Plaka Üzerine Konik Yayların Yerleştirildiği Güneş Enerjili Hava Kollektörünün Bulanık Mantık ile Modellenmesi

Reflectance, Transmittance and Absorptance of HDPE, LDPE, Glass and Sand Layer Used in a SAH

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