Agriculture Reference
In-Depth Information
19
20
15
10
5
0
-5
-10
0
20
40
60
Ventilation rate (volumes h
-1
)
20
A
B
Wind velocity
C
Min.
0
x1
x2
x3
100
Vent opening (%)
Plate 18.
The greenhouse that uses a screen as cladding material is known as a screenhouse.
Plate 19.
High greenhouse air temperatures (with respect to the exterior temperature) as a function of the
ventilation rate with a well-developed crop, under different conditions. Green, with shading; blue, with shading and
air humidification; red, without shading or air humidification (source: J.I. Montero).
Plate 20.
Set point values for carbon enrichment (CO
2
) depending on the demand of heat (A) and the solar
radiation intensity level (A and B) depending on the vent opening conditions (adapted from Nederhoff, 1995). x1
represents the lower degree of vent opening that determines changes in the CO
2
enrichment set point. x2 and x3
represent the vent openings that determine the minimum CO
2
enrichment set point when radiation is below a
preset level (x2) or when radiation exceeds a preset level (x3). See explanation in the text (Chapter 9).
