Effect of the Shape Surface of Absorber Plate on Performance of Built-in-Storage Solar Water Heater
Omer Khalil Ahmad,
Ahmed Hassan Ahmed,
Obiad Majeed Ali
Issue:
Volume 3, Issue 5, October 2014
Pages:
58-65
Received:
6 October 2014
Accepted:
16 October 2014
Published:
30 October 2014
Abstract: An experimental and numerical study was carried out on a storage solar collectors to verify its suitability for domestic use. These storage collectors can be used as storage water tanks to replace the ordinary cubical or cylindrical tank commonly used in Iraqi houses. The paper includes study the effect of the shape surface of absorber plate on performance of storage solar collector by construction of three-box type, built –in-storage water heaters with three different shape of front absorber plat, flat, wavy, and zigzag shapes. Experiments were conducted in summer and autumn seasons, and the results were comparable to the theoretical calculation. The results indicated clearly that the storage collector can be used for providing hot water for domestic uses, the zigzag storage collector was the best to obtain a high temperature than the other two designs, also the finite difference model proved to be useful for prediction of water temperatures under variable operating conditions.
Abstract: An experimental and numerical study was carried out on a storage solar collectors to verify its suitability for domestic use. These storage collectors can be used as storage water tanks to replace the ordinary cubical or cylindrical tank commonly used in Iraqi houses. The paper includes study the effect of the shape surface of absorber plate on per...
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Volume Models for Single Trees in Tropical Rainforests in Tanzania
Abel Malyango Masota,
Eliakimu Zahabu,
Rogers Ernest Malimbwi,
Ole Martin Bollandsås,
Tron Haakon Eid
Issue:
Volume 3, Issue 5, October 2014
Pages:
66-76
Received:
15 October 2014
Accepted:
31 October 2014
Published:
10 November 2014
Abstract: The present study was the first to develop total tree, stem and branches volume models for rainforests in south-eastern Africa based on destructive sampling. The number of sample trees was 60 and diameter at breast height (dbh) and total tree height (h) ranged from 6 to 117 cm and from 6.4 m to 50 m, respectively. Large parts of the total volume and stem volume variations were explained by the models (Pseudo-R2 ranged from 0.85 to 0.93) and they performed relatively well over different size classes. When considering the challenges in height measurements in rainforests, we in general recommend applying model 3 with dbh only as independent variable. For large trees we recommend model 2 (dbh and h as independent variables) because of the moderating effect h has on volume predictions. If accurate stem volumes are needed for forestry licensing or for calculating compensation of timber loss, we also recommend model 2. As long as the allometry of the trees obviously is not different from that of our study site, the developed models may also be applied for rainforests elsewhere in Tanzania, but further testing of the models is also recommended.
Abstract: The present study was the first to develop total tree, stem and branches volume models for rainforests in south-eastern Africa based on destructive sampling. The number of sample trees was 60 and diameter at breast height (dbh) and total tree height (h) ranged from 6 to 117 cm and from 6.4 m to 50 m, respectively. Large parts of the total volume an...
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