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פותח על ידי קלירמאש פתרונות בע"מ -
Effect of cyclic heating and a thermal screen on the nocturnal heat loss and microclimate of a greenhouse
Year:
2009
Source of publication :
Biosystems Engineering
Authors :
אנטלר, אהרון
;
.
ברק, מוטי
;
.
טייטל, מאיר
;
.
Volume :
102
Co-Authors:
Teitel, M., Institute of Agricultural Engineering, A.R.O., Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel
Barak, M., Institute of Agricultural Engineering, A.R.O., Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel
Antler, A., Institute of Agricultural Engineering, A.R.O., Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel
Facilitators :
From page:
162
To page:
170
(
Total pages:
9
)
Abstract:
Experiments were carried out in a small heated greenhouse, in which roses were grown. Hot-air heating was applied only during the night. The hot air was distributed to the crop via perforated polyethylene sleeves placed on the ground between the rows of plants. To determine the effect of a thermal screen on the energy consumption and on the greenhouse microclimate under cyclic heating, a horizontal 20%-aluminised thermal screen was automatically deployed every night between 18:00 and 06:00, at a height of about 2.5 m above the ground. The screen was deployed during two of the four weeks of data collection. The air temperature in the greenhouse at night was usually maintained at 16-18 °C by an on-off controller. The thermal screen did not reduce the heat loss from the greenhouse because it was relatively small in area and only 20% of its area was covered by reflective aluminised material. Yet, despite this, it kept the canopy temperature slightly higher than without a screen. Two different models were used to determine the global heat transfer coefficient from the greenhouse: the first assumed a quasi-steady-state heating condition; the second used a transient approach in which heat storage in the greenhouse air and crop was taken into account. It was found that there was a small difference between the results of the two models. A simple model for calculating leaf temperature is offered and used for calculating the temperature of an upper leaf. The model and experimental results are in good agreement even under unsteady heating. © 2008 IAgrE.
Note:
Related Files :
Air temperature (T)
Crops
Data collections
greenhouse effect
greenhouses
heating
Rosa
Simple modeling
עוד תגיות
תוכן קשור
More details
DOI :
10.1016/j.biosystemseng.2008.11.013
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
26529
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:23
Scientific Publication
Effect of cyclic heating and a thermal screen on the nocturnal heat loss and microclimate of a greenhouse
102
Teitel, M., Institute of Agricultural Engineering, A.R.O., Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel
Barak, M., Institute of Agricultural Engineering, A.R.O., Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel
Antler, A., Institute of Agricultural Engineering, A.R.O., Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel
Effect of cyclic heating and a thermal screen on the nocturnal heat loss and microclimate of a greenhouse
Experiments were carried out in a small heated greenhouse, in which roses were grown. Hot-air heating was applied only during the night. The hot air was distributed to the crop via perforated polyethylene sleeves placed on the ground between the rows of plants. To determine the effect of a thermal screen on the energy consumption and on the greenhouse microclimate under cyclic heating, a horizontal 20%-aluminised thermal screen was automatically deployed every night between 18:00 and 06:00, at a height of about 2.5 m above the ground. The screen was deployed during two of the four weeks of data collection. The air temperature in the greenhouse at night was usually maintained at 16-18 °C by an on-off controller. The thermal screen did not reduce the heat loss from the greenhouse because it was relatively small in area and only 20% of its area was covered by reflective aluminised material. Yet, despite this, it kept the canopy temperature slightly higher than without a screen. Two different models were used to determine the global heat transfer coefficient from the greenhouse: the first assumed a quasi-steady-state heating condition; the second used a transient approach in which heat storage in the greenhouse air and crop was taken into account. It was found that there was a small difference between the results of the two models. A simple model for calculating leaf temperature is offered and used for calculating the temperature of an upper leaf. The model and experimental results are in good agreement even under unsteady heating. © 2008 IAgrE.
Scientific Publication
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