Development and Validation of a Mathematical Model for Ventilation Rate in Crop Protection Structures

Al-Shamiry, Faisal Mohammed Seif and Ahmad, Desa (2010) Development and Validation of a Mathematical Model for Ventilation Rate in Crop Protection Structures. Pertanika Journal of Science & Technology, 18 (1). pp. 111-120. ISSN 0128-7680

[img] PDF


Natural ventilation is defined as the number of air exchanges per hour per unit floor area necessary to reduce high indoor air temperature and humidity. In addition, it maintains the concentration of carbon dioxide. Natural ventilation is preferred in mechanical system as the ventilation opening is built into the greenhouse, with lower construction cost and no energy and maintenance inputs are required. A mathematical model to quantify natural ventilation rates was developed and verified in large-scale greenhouse structures. For this purpose, four Naturally Ventilated Tropical Greenhouse Structures were designed and constructed at the Malaysian Agricultural Research and Development Institute (MARDI). These were single, double, triple, and quadruple span structures with floor areas of 500 m2, 1000 m2, 1500 m2 and 2000 m2, respectively. This paper presents the validation of a mathematical model which was developed to quantify natural ventilation rates which are very crucial to reduce high in-house temperature built up in the tropics. Regression equations of natural ventilation against wind speed were found to be Φw = 0.0632V, Φw= 0.0395V, Φw= 0.0316V and Φw= 0.0276V for the single, double, triple and quadruple spans, respectively. Meanwhile, coefficients of determination showed strong relationships between ventilation rate and wind speed, with R2 = 0.9999 for all structures. Larger floor area was found to have higher in-house temperature than smaller ones. Ventilation rate inside the single-span structure was found to be higher compared to the multi-span structures, which increased linearly with the increasing wind speed at the eaves of structure.

Item Type:Article
Keyword:Natural ventilation, wind effect, multi-span, greenhouse structure
Faculty or Institute:Faculty of Engineering
Publisher:Universiti Putra Malaysia Press
ID Code:10584
Deposited By: Anas Yahaya
Deposited On:15 Mar 2011 11:43
Last Modified:27 May 2013 07:46

Repository Staff Only: Edit item detail

Document Download Statistics

This item has been downloaded for since 15 Mar 2011 11:43.

View statistics for "Development and Validation of a Mathematical Model for Ventilation Rate in Crop Protection Structures"

Universiti Putra Malaysia Institutional Repository

Universiti Putra Malaysia Institutional Repository is an on-line digital archive that serves as a central collection and storage of scientific information and research at the Universiti Putra Malaysia.

Currently, the collections deposited in the IR consists of Master and PhD theses, Master and PhD Project Report, Journal Articles, Journal Bulletins, Conference Papers, UPM News, Newspaper Cuttings, Patents and Inaugural Lectures.

As the policy of the university does not permit users to view thesis in full text, access is only given to the first 24 pages only.