Thermal performance of a packed bed double-pass solar air heater

Ramadan, M.R.I.; El-Sebaii, A.A.; Aboul-Enein, S.; El-Bialy, E.

doi:10.1016/j.energy.2006.09.019

Cited by 132 publications

(57 citation statements)

References 19 publications

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“…This configuration increases pressure drop in the flow, but the paper does not specify how much. Ramadan et al [42] also reported an efficiency increase using double pass heating.…”

Section: Solar Air Heater Designsmentioning

confidence: 88%

The potential of solar-driven humidification–dehumidification desalination for small-scale decentralized water production

Narayan

Sharqawy

Summers

et al. 2010

Renewable and Sustainable Energy Reviews

358

132

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World-wide water scarcity, especially in the developing world, indicates a pressing need to develop inexpensive, decentralized small-scale desalination technologies which use renewable resources of energy. This paper provides a comprehensive review of the stateof-the-art in one of the most promising of these technologies, solar-driven humidification-dehumidification (HDH) desalination. Previous studies have investigated many different variations on the HDH cycle. In this paper, performance parameters which enable comparison of the various versions of the HDH cycle have been defined and evaluated. To better compare these cycles, each has been represented in psychometric coordinates. The principal components of the HDH system are also reviewed and compared, including the humidifier, solar heaters, and dehumidifiers. Particular attention is given to solar air heaters, for which design data is limited; and direct air heating is compared to direct water heating in the cycle assessments. Alternative processes based on the HDH concept are also reviewed and compared. Further, novel proposals for improvement of the HDH cycle are outlined. It is concluded that HDH technology has great promise for decentralized small-scale water production applications, although additional research and development is needed for improving system efficiency and reducing capital cost.

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“…This configuration increases pressure drop in the flow, but the paper does not specify how much. Ramadan et al [42] also reported an efficiency increase using double pass heating.…”

Section: Solar Air Heater Designsmentioning

confidence: 88%

The potential of solar-driven humidification–dehumidification desalination for small-scale decentralized water production

Narayan

Sharqawy

Summers

et al. 2010

Renewable and Sustainable Energy Reviews

358

132

View full text Add to dashboard Cite

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“…Hava akışına paralel olarak yerleştirilen kanatçıkların ısıl verimi önemli ölçüde arttırdığını belirtmiştir [3]. Isıl verimi iyileştirmenin diğer bir yolu ise kollektör içerisinde gözenekli yapılar kullanmaktır [4][5][6]. Aldabbah vd., tek ve çift geçişli güneş enerjili hava kollektörlerinde akışkan yatağı olarak tel örgü yapısını kullanmışlar ve bunun performansını deneysel olarak test etmişlerdir.…”

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 experiment by Omojaro and Aldabbagh (2010) showed that, there was an increase of collector efficiency by 4.7% when reducing the height of first pass from 7 to 3 cm. Ramadan et al (2007) suggested using double pass solar air collector with air passing above the absorber plate before turning to pass below it. Ramani et al (2010) conducted experimental study involving double and single pass air collector and concluded that, the doublepass design had a thermal efficiency of about 10% higher compared to single-pass design.…”

Section: Influence Of Air Flow Patternsmentioning

confidence: 99%

Experimental analysis of air flow patterns in perfomance of flat plate solar collectors

Ramadhani¹,

Minja²,

Njau³

2015

Afr. J. Agric. Res.

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Solar drying is one of the promising methods of reducing post-harvest losses in rural areas. Studies have shown that, heat transfer mechanisms in a solar collector influences the performance of solar dryers. This study aims at improving heat transfer in flat plate solar collectors by designing different air flow patterns inside the collector. Three flat plate solar collectors were constructed by using Pterocarpus timber (Mninga) and tested for their effect in heat transfer at various flow patterns. Three different flow patterns namely: single duct front pass, double duct parallel flow and double duct counter flow were designed and tested. Experimental results show that collector efficiency of single duct front pass, double duct front pass and double duct counter flow were 30.6, 36.1 and 38.2% respectively. It was found that, double duct flow gives improved performance compared to single duct flow due to the increased heat transfer area. In additional, double duct counter flow showed superior performance compared to double duct parallel flow due to extended heat transfer area and the advantage of air preheating at the inlet which reduces heat losses through glazing. Through this study, it was concluded that, solar collector designs with double duct counter flow can improve collector performance for up to 8.3% compared to single duct front pass.

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Thermal performance of a packed bed double-pass solar air heater

Cited by 132 publications

References 19 publications

The potential of solar-driven humidification–dehumidification desalination for small-scale decentralized water production

The potential of solar-driven humidification–dehumidification desalination for small-scale decentralized water production

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

Experimental analysis of air flow patterns in perfomance of flat plate solar collectors

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