Impact of Collector Slope on Power Output and System Efficiency in Solar Chimney Power Plants

Abstract

In this study, impact of collector slope on the system is analysed with 3D CFD model developed based on Manzanares prototype. In the numerical model, DO (discrete ordinates) radiation model for solar load and RNG k-ε turbulence model for turbulent air flow in the system are simultaneously utilised. Maximum air velocity within the system for incoming solar radiation of    1000 W/m2 is determined to be 14.3 m/s, which agrees with experimental data of 15 m/s. In the Manzanares prototype, collector inlet height is given as 1.85 m. Here, collector inlet height is kept constant and the collector outlet height is configured as 2.91, 3.97, 5.04, 6.12 and 7.17 m, so the change in system performance is evaluated in cases where the collector slope is 0.5, 1, 1.5, 2 and 2.5°. Findings show that the increase in collector slope rises mass flow rate of air in the system and this improves power output of the system. Collector efficiency is 38.7% for the
horizontal collector which represents the reference case, whereas it is enhanced to 41.5% when collector slope is 1°. Power output of the system at reference case is 54.5 kW, while it is    57.1 kW when collector slope is 2.5°. 

Keywords

• Solar chimney power plants
• collector slope
• power output
• system efficiency

GÜNEŞ BACASI GÜÇ SANTRALLERİNDE TOPLAYICI EĞİMİNİN ÇIKIŞ GÜCÜNE VE SİSTEM VERİMİNE ETKİSİ

Abstract

Bu çalışmada toplayıcı eğiminin sisteme etkisi Manzanares prototipi esas alınarak geliştirilen 3 boyutlu CFD modeli ile analiz edilmektedir. Nümerik modelde güneş yükü için DO (discrete ordinates) ışınım modeli ve sistem içerisindeki hava hareketi için RNG k-ε türbülans modeli birleştirilerek uygulanmaktadır. 1000 W/m2 güneş ışınımında sistemdeki maksimum hız 14.3 m/s olarak bulunurken bu değer deneysel veri olan 15 m/s ile uyum içerisindedir. Manzanares prototipinde toplayıcı giriş yüksekliği 1.85 m olarak verilmektedir. Bu çalışma kapsamında toplayıcı giriş yüksekliği sabit tutularak, toplayıcı çıkış yüksekliği sırası ile 2.91, 3.97, 5.04, 6.12 ve 7.17 m olarak tasarlanmakta ve bu sayede toplayıcı eğiminin 0.5, 1, 1.5, 2 ve 2.5° olduğu durumlarda sistemin performansındaki değişim değerlendirilmektedir. Elde edilen sonuçlar toplayıcı eğimindeki artışın sistemdeki hava hareketinin kütlesel debisini arttırdığını ve bu artışın sistemin güç çıkışını iyileştirdiğini göstermektedir. Referans durumu temsil eden eğimsiz toplayıcı için toplayıcı verimi %38.7 iken toplayıcı eğimi 1° olduğunda verimin %41.5’e iyileştiği gözlenmektedir. Sistemin çıkış gücü referans durumda 54.5 kW iken toplayıcı eğimi 2.5° olduğunda 57.1 kW olarak belirlenmektedir.

Keywords

• Güneş bacası güç santralleri
• toplayıcı eğimi
• çıkış gücü
• sistem verimi

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