A study of natural ventilation in an Almería-type greenhouse with insect screens by means of tri-sonic anemometry

Molina-Aiz, F.D.; Valera, D.L.; Peña, Araceli; Gil, J.; López, Alejandro López

doi:10.1016/j.biosystemseng.2009.06.013

Cited by 65 publications

(69 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Measurements were carried out in the compartment marked in red in Figure , higher than those expected to be measured inside the greenhouse, which should be in a much lower range (Wang et al, 1999;Molina-Aiz et al,2009). , higher than those expected to be measured inside the greenhouse, which should be in a much lower range (Wang et al, 1999;Molina-Aiz et al, 2009 Once calibrated, sensors were fi nally installed in the commercial greenhouse following the arrangement that can be seen on Figure 7.…”

Section: Andmentioning

confidence: 99%

“…, higher than those expected to be measured inside the greenhouse, which should be in a much lower range (Wang et al, 1999;Molina-Aiz et al, 2009 Once calibrated, sensors were fi nally installed in the commercial greenhouse following the arrangement that can be seen on Figure 7. The 3 sensors were completely aligned vertically; sensor c was located immediately above the top screen (the shading screen); sensor b was located in between both screens; and sensor a was located below the lower screen (the energy saving/black-out screen).…”

Section: Andmentioning

confidence: 99%

See 1 more Smart Citation

Energy saving screen materials : measurement method of radiation exchange, air permeability and humidity transport and a calculation method for energy saving

Hemming¹,

Technologie²,

Romero³

et al. 2017

View full text Add to dashboard Cite

De doelstellingen van het project waren het kwantifi ceren van in kassen gebruikte scherm eigenschappen (emissie en transmissie voor warmtestraling, luchtdoorlaatbaarheid en vochttransport) en de bepaling van de totale energiebesparing onder gedefi nieerde omstandigheden om de prestaties van verschillende schermen (en leveranciers) met elkaar te kunnen vergelijken. Dit helpt telers om meer informatie te krijgen over relevante scherm eigenschappen en stelt hen in staat om een weloverwogen keuze voor een investering te doen. De resultaten tonen aan dat ondoorlatende schermen en schermen met lage emissie en transmissie voor warmtestraling de hoogste energiebesparing geven. Doorlaatbare schermen geven de hoogste vochtafvoer en de laagste luchtvochtigheid tijdens scherm gebruik zonder de noodzaak voor extra mechanische ontvochtiging. AbstractThe objectives of the project were the quantifi cation of the greenhouse screen properties (emissivity and transmissivity for thermal infrared radiation, air permeability and humidity transport) and the determination of the total energy saving under defi ned conditions in order to be able to compare the performance of different screens (and suppliers) with each other. This helps growers to understand more about screen properties and allows them to make an informed choice of investment. The results show that impermeable screens and screens with low emissivity and low transmissivity for thermal infrared radiation give highest energy saving. Permeable screens give highest transport for humidity and lowest air humidity during screen usage without the need for additional mechanical dehumidifi cation.

show abstract

Section: Andmentioning

confidence: 99%

Section: Andmentioning

confidence: 99%

Energy saving screen materials : measurement method of radiation exchange, air permeability and humidity transport and a calculation method for energy saving

Hemming¹,

Technologie²,

Romero³

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The air moves towards the southern side vent to exit the greenhouse and towards the western side, where there is no outlet. Counterflows inside the greenhouse have been observed by other authors (Wang & Deltour, 1999;Molina-Aiz et al, 2009). Opening the western side of the greenhouse might achieve a better combination of the wind and thermal effects in natural ventilation of the greenhouse.…”

Section: Airflow Inside the Greenhouse With Poniente Southwest Windsmentioning

confidence: 68%

“…The air velocity was measured over 3 min at each point. This time period is a compromise between a shorter one that may reduce accuracy and a longer one that may increase the overall difference with regard to outside microclimate parameters (Molina-Aiz et al, 2009). As it proved difficult to place the anemometers at the roof vent [Suppl.…”

Section: Experimental Design 1: Airflow Inside a Naturally Ventilatedmentioning

confidence: 99%

“…Although many authors have obtained the coefficients C d and C w that allow the semi-empirical models to be applied (Kittas et al, 1996Papadakis et al, 1996;Boulard et al, 1997;Fatnassi et al, 2002;Teitel et al, 2008;Molina-Aiz et al, 2009, there is still considerable debate as to the exact relationship between the wind and thermal effects in the natural ventilation of greenhouses. Papadakis et al (1996) found that the thermal effect was fundamental for winds of less than 1.8 m s -1 , while Boulard & Baille (1995) set this speed at 1.5 m s -1 and Sase et al (1984) at 1 m s -1 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

Determinación de los patrones de flujo de aire en un invernadero multitúnel mediante anemometría sónica

López¹,

Valera²,

Molina-Aiz³

et al. 2012

Span. j. agric. res.

Self Cite

View full text Add to dashboard Cite

The present work describes a methodology for studying natural ventilation in Mediterranean greenhouses using sonic anemometry. The experimental work took place in the three-span greenhouse located at the agricultural research farm belonging to the University of Almería. This methodology has allowed us to obtain patterns of natural ventilation of the experimental greenhouse under the most common wind regimes for this region. It has also enabled us to describe how the wind and thermal effects interact in the natural ventilation of the greenhouse, as well as to detect deficiencies in the ventilation of the greenhouse, caused by the barrier effect of the adjacent greenhouse (imply a mean reduction in air velocity close to the greenhouse when facing windward of 98% for u, 63% for u y , and more importantly 88% for u x , the component of air velocity that is perpendicular to the side vent). Their knowledge allows us to improve the current control algorithms that manage the movement of the vents. In this work we make a series of proposals that could substantially improve the natural ventilation of the experimental greenhouse. For instance, install vents equipped with ailerons which guide the air inside, or with vents in which the screen is not placed directly over the side surface of the greenhouse. A different proposal is to prolong the opening of the side vents down to the soil, thus fomenting the entrance of air at crop level.Additional key words: buoyancy; insect-proof screens; natural ventilation; wind effect. ResumenDeterminación de los patrones de flujo de aire en un invernadero multitúnel mediante anemometría sónicaEn este trabajo se ha desarrollado una metodología para estudiar la ventilación natural en invernaderos mediterrá-neos mediante anemometría sónica. Los ensayos se han realizado en un invernadero multitúnel de tres módulos situado en el Campo de Prácticas de la Universidad de Almería. Esta metodología nos ha permitido obtener los patrones de ventilación natural del invernadero experimental para los vientos más comunes de la región. También nos ha permitido describir la interacción entre el efecto eólico y térmico, así como detectar deficiencias en la ventilación natural del invernadero debidas al efecto barrera de otro invernadero adyacente (provocando una reducción media en la velocidad del aire en el exterior de la ventana de barlovento de hasta el 98% para u, 63% para u y y, más importante, 88% para u x , la componente de la velocidad del aire que es perpendicular a la superficie de ventilación lateral). Los conocimientos adquiridos en este trabajo nos permitirán mejorar los algoritmos de control del sistema de ventilación. En este trabajo se realizan una serie de propuestas que podrían mejorar sustancialmente la ventilación natural del invernadero. Por ejemplo, se proponen algunas posibles modificaciones de la configuración de las ventanas laterales, buscando una mayor captación del aire exterior: se podría optar por ventanas dotadas de alerones exteriores que dirijan al aire hacia el inte...

show abstract

A numerical modelling approach for biomass field drying

Bartzanas

Bochtis

Sørensen

et al. 2010

Biosystems Engineering

View full text Add to dashboard Cite

A study of natural ventilation in an Almería-type greenhouse with insect screens by means of tri-sonic anemometry

Cited by 65 publications

References 66 publications

Energy saving screen materials : measurement method of radiation exchange, air permeability and humidity transport and a calculation method for energy saving

Energy saving screen materials : measurement method of radiation exchange, air permeability and humidity transport and a calculation method for energy saving

Determinación de los patrones de flujo de aire en un invernadero multitúnel mediante anemometría sónica

A numerical modelling approach for biomass field drying

Contact Info

Product

Resources

About