Sains Malaysiana 45(3)(2016): 489–497

Development of an Efficient Flat Plate Solar Air Heater for Drying and Water Heating Purposes

(Pembangunan Sebuah Pemanas Udara Suria Plat Rata yang Cekap bagi Tujuan Pengeringan dan Pemanasan Air)

M. HANIF¹*, M.K. KHATTAK¹, M. AMIN¹, M. RAMZAN¹, S. ZAKIR², S. ULLAH² & Z. KHAN²

¹Department of Agricultural Mechanization, The University of Agriculture Peshawar, Pakistan

²Department of Environmental Sciences, University of Peshawar, Pakistan

Received: 15 May 2014/Accepted: 3 September 2015

ABSTRACT

A 1.7 m² flat plate solar air heater was designed and developed in the Department of Agricultural Mechanization, The University of Agriculture Peshawar, Pakistan in collaboration with the Department of Environmental Sciences, University of Peshawar, Pakistan. It was operated under an average solar irradiance of 0.9 kJ.m^-2.h^-1 in the month of September, 2013. It worked under an efficiency of 7.5 to 21%. The heat collected by the air heater was given to air flowing as a medium inside it. This hot air was given to a drying section and water heating tank for drying and water heating purposes. The drying section provided a temperature in the range of 40-50^oC and humidity of 10-30% from 10:00 am to 3:00 pm. The water heating tank provides hot water with a temperature of 35- 45^oC from 10:00 am to 5:00 pm. Furthermore, the drying section was used to dry apples, onions and persimmons. All the products showed a consistent moisture loss from them with an optimum drying rate. The two term exponential model showed that all the three products dried have a good correlation with drying time with R² values higher than 0.90. It was concluded that flat plate solar air heaters is the best technology for water heating and drying purposes and is a good alternative of conventional energy sources.

Keywords: Efficiency; drying; flat plate solar air heater; solar energy; water heating

ABSTRAK

Sebuah pemanas udara suria plat rata berukuran 1.7 m² direka dan dibangunkan di Jabatan Pertanian Pemesinkan, Universiti Pertanian Peshawar, Pakistan dengan kerjasama Jabatan Sains Alam Sekitar, Universiti Peshawar, Pakistan. Ia telah beroperasi menggunakan purata sinaran suria sebanyak 0.9 kJ.m^-2.jam^-1 pada bulan September 2013. Ia menggunakan kecekapan 7.5 hingga 21%. Haba yang dikumpul oleh pemanas udara telah diberikan kepada udara yang mengalir sebagai medium di dalamnya. Udara panas ini telah diberikan kepada bahagian pengeringan dan tangki pemanas air untuk tujuan pengeringan dan pemanasan air. Bahagian pengeringan menyediakan suhu dalam lingkungan 40-50^oC dan kelembapan 10-30% dari 10:00 pagi hingga 3:00 petang. Tangki pemanas air menyediakan air panas dengan suhu 35-45^oC dari 10:00 pagi hingga 5:00 petang. Selain itu bahagian pengeringan juga digunakan untuk mengeringkan epal, bawang dan pisang kaki. Semua produk menunjukkan kehilangan lembapan yang konsisten dengan kadar pengeringan optimum. Model eksponen dua istilah menunjukkan bahawa tiga produk kering tersebut mempunyai kolerasi yang baik dengan masa pengeringan dengan nilai R² lebih tinggi daripada 0.90. Kesimpulannya, pemanas udara suria plat rata adalah teknologi terbaik untuk tujuan pemanasan air dan pengeringan dan adalah alternatif yang baik sebagai sumber tenaga konvensional.

Kata kunci: Kecekapan; pemanas air; pemanas udara suria plat rata; pengeringan; tenaga solar

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*Corresponding author; email: hanif_mechanization@aup.edu.pk