Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse
Autor(a) principal: | |
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Data de Publicação: | 2013 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Scientia Agrícola (Online) |
Texto Completo: | https://www.revistas.usp.br/sa/article/view/64047 |
Resumo: | Natural ventilation is the most important method of climate control in Mediterranean greenhouses. In this study, the microclimate and air flow inside a Mediterranean greenhouse were evaluated by means of sonic anemometry. Experiments were carried out in conditions of moderate wind (≈ 4.0 m s-1), and at low wind speed (≈ 1.8 m s-1) the natural ventilation of the greenhouse was supplemented by two horizontal air flow fans. The greenhouse is equipped with a single roof vent opening to the windward side and two side vents, the windward one being blocked by another greenhouse close to it, while the leeward one is free of obstacles. When no fans are used, air enters through the roof vent and exits through both side vents, thus flowing contrary to the thermal effect which causes hot air to rise and impairing the natural ventilation of the greenhouse. Using fans inside the greenhouse helps the air to circulate and mix, giving rise to a more homogeneous inside temperature and increasing the average value of normalized air velocity by 365 %. These fans also increase the average values of kinetic turbulence energy inside the greenhouse by 550 % compared to conditions of natural ventilation. As the fans are placed 4 m away from the side vents, their effect on the entrance of outside air is insufficient and they do not help to reduce the inside temperature on hot days with little wind. It is therefore recommended to place the fans closer to the side vents to allow an additional increase of the air exchange rate of greenhouses. |
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Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse climate controlmicrolimatesonic anemometry Natural ventilation is the most important method of climate control in Mediterranean greenhouses. In this study, the microclimate and air flow inside a Mediterranean greenhouse were evaluated by means of sonic anemometry. Experiments were carried out in conditions of moderate wind (≈ 4.0 m s-1), and at low wind speed (≈ 1.8 m s-1) the natural ventilation of the greenhouse was supplemented by two horizontal air flow fans. The greenhouse is equipped with a single roof vent opening to the windward side and two side vents, the windward one being blocked by another greenhouse close to it, while the leeward one is free of obstacles. When no fans are used, air enters through the roof vent and exits through both side vents, thus flowing contrary to the thermal effect which causes hot air to rise and impairing the natural ventilation of the greenhouse. Using fans inside the greenhouse helps the air to circulate and mix, giving rise to a more homogeneous inside temperature and increasing the average value of normalized air velocity by 365 %. These fans also increase the average values of kinetic turbulence energy inside the greenhouse by 550 % compared to conditions of natural ventilation. As the fans are placed 4 m away from the side vents, their effect on the entrance of outside air is insufficient and they do not help to reduce the inside temperature on hot days with little wind. It is therefore recommended to place the fans closer to the side vents to allow an additional increase of the air exchange rate of greenhouses. Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz2013-08-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://www.revistas.usp.br/sa/article/view/6404710.1590/S0103-90162013000400001Scientia Agricola; v. 70 n. 4 (2013); 219-228Scientia Agricola; Vol. 70 Núm. 4 (2013); 219-228Scientia Agricola; Vol. 70 No. 4 (2013); 219-2281678-992X0103-9016reponame:Scientia Agrícola (Online)instname:Universidade de São Paulo (USP)instacron:USPenghttps://www.revistas.usp.br/sa/article/view/64047/66756Copyright (c) 2015 Scientia Agricolainfo:eu-repo/semantics/openAccessLópez, AlejandroValera, Diego LuisMolina-Aiz, Francisco DomingoPeña, Araceli2013-10-29T16:17:46Zoai:revistas.usp.br:article/64047Revistahttp://revistas.usp.br/sa/indexPUBhttps://old.scielo.br/oai/scielo-oai.phpscientia@usp.br||alleoni@usp.br1678-992X0103-9016opendoar:2013-10-29T16:17:46Scientia Agrícola (Online) - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse |
title |
Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse |
spellingShingle |
Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse López, Alejandro climate control microlimate sonic anemometry |
title_short |
Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse |
title_full |
Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse |
title_fullStr |
Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse |
title_full_unstemmed |
Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse |
title_sort |
Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse |
author |
López, Alejandro |
author_facet |
López, Alejandro Valera, Diego Luis Molina-Aiz, Francisco Domingo Peña, Araceli |
author_role |
author |
author2 |
Valera, Diego Luis Molina-Aiz, Francisco Domingo Peña, Araceli |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
López, Alejandro Valera, Diego Luis Molina-Aiz, Francisco Domingo Peña, Araceli |
dc.subject.por.fl_str_mv |
climate control microlimate sonic anemometry |
topic |
climate control microlimate sonic anemometry |
description |
Natural ventilation is the most important method of climate control in Mediterranean greenhouses. In this study, the microclimate and air flow inside a Mediterranean greenhouse were evaluated by means of sonic anemometry. Experiments were carried out in conditions of moderate wind (≈ 4.0 m s-1), and at low wind speed (≈ 1.8 m s-1) the natural ventilation of the greenhouse was supplemented by two horizontal air flow fans. The greenhouse is equipped with a single roof vent opening to the windward side and two side vents, the windward one being blocked by another greenhouse close to it, while the leeward one is free of obstacles. When no fans are used, air enters through the roof vent and exits through both side vents, thus flowing contrary to the thermal effect which causes hot air to rise and impairing the natural ventilation of the greenhouse. Using fans inside the greenhouse helps the air to circulate and mix, giving rise to a more homogeneous inside temperature and increasing the average value of normalized air velocity by 365 %. These fans also increase the average values of kinetic turbulence energy inside the greenhouse by 550 % compared to conditions of natural ventilation. As the fans are placed 4 m away from the side vents, their effect on the entrance of outside air is insufficient and they do not help to reduce the inside temperature on hot days with little wind. It is therefore recommended to place the fans closer to the side vents to allow an additional increase of the air exchange rate of greenhouses. |
publishDate |
2013 |
dc.date.none.fl_str_mv |
2013-08-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.revistas.usp.br/sa/article/view/64047 10.1590/S0103-90162013000400001 |
url |
https://www.revistas.usp.br/sa/article/view/64047 |
identifier_str_mv |
10.1590/S0103-90162013000400001 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
https://www.revistas.usp.br/sa/article/view/64047/66756 |
dc.rights.driver.fl_str_mv |
Copyright (c) 2015 Scientia Agricola info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Copyright (c) 2015 Scientia Agricola |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz |
publisher.none.fl_str_mv |
Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz |
dc.source.none.fl_str_mv |
Scientia Agricola; v. 70 n. 4 (2013); 219-228 Scientia Agricola; Vol. 70 Núm. 4 (2013); 219-228 Scientia Agricola; Vol. 70 No. 4 (2013); 219-228 1678-992X 0103-9016 reponame:Scientia Agrícola (Online) instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Scientia Agrícola (Online) |
collection |
Scientia Agrícola (Online) |
repository.name.fl_str_mv |
Scientia Agrícola (Online) - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
scientia@usp.br||alleoni@usp.br |
_version_ |
1800222791964819456 |