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Optimizing illumination in the greenhouse using a 3D model of tomato and a ray tracer.

de Visser PH, Buck-Sorlin GH, van der Heijden GW - Front Plant Sci (2014)

Bottom Line: Results were compared to the standard configuration.Moreover, adaptation of leaf angles was incorporated for testing their effect on light use efficiency (LUE).The simulated leaf angles did not affect light absorption from inter-lighting LED modules, but the scenario with LEDs shining slightly upward (20(°)) increased light absorption and LUE relative to default horizontal beaming LEDs.

View Article: PubMed Central - PubMed

Affiliation: Department of Greenhouse Horticulture, Wageningen University and Research Centre Wageningen, Netherlands.

ABSTRACT
Reduction of energy use for assimilation lighting is one of the most urgent goals of current greenhouse horticulture in the Netherlands. In recent years numerous lighting systems have been tested in greenhouses, yet their efficiency has been very difficult to measure in practice. This simulation study evaluated a number of lighting strategies using a 3D light model for natural and artificial light in combination with a 3D model of tomato. The modeling platform GroIMP was used for the simulation study. The crop was represented by 3D virtual plants of tomato with fixed architecture. Detailed data on greenhouse architecture and lamp emission patterns of different light sources were incorporated in the model. A number of illumination strategies were modeled with the calibrated model. Results were compared to the standard configuration. Moreover, adaptation of leaf angles was incorporated for testing their effect on light use efficiency (LUE). A Farquhar photosynthesis model was used to translate the absorbed light for each leaf into a produced amount of carbohydrates. The carbohydrates produced by the crop per unit emitted light from sun or high pressure sodium lamps was the highest for horizontal leaf angles or slightly downward pointing leaves, and was less for more upward leaf orientations. The simulated leaf angles did not affect light absorption from inter-lighting LED modules, but the scenario with LEDs shining slightly upward (20(°)) increased light absorption and LUE relative to default horizontal beaming LEDs. Furthermore, the model showed that leaf orientation more perpendicular to the string of LEDs increased LED light interception. The combination of a ray tracer and a 3D crop model could compute optimal lighting of leaves by quantification of light fluxes and illustration by rendered lighting patterns. Results indicate that illumination efficiency increases when the lamp light is directed at most to leaves that have a high photosynthetic potential.

No MeSH data available.


Computed light intensity (W per sensor with 6 cm radius) at the trajectories of Figure 3, with and without light intercepting plants (plant positions indicated by arrows). For this simulation the HPS lamps had an arbitrary light output of 1000 W m-2.
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Figure 4: Computed light intensity (W per sensor with 6 cm radius) at the trajectories of Figure 3, with and without light intercepting plants (plant positions indicated by arrows). For this simulation the HPS lamps had an arbitrary light output of 1000 W m-2.

Mentions: The light model computed considerable horizontal differences in light intensity within the crop. For HPS lamps without plants, the visual rendering seemed to indicate large intensity differences in the area between lamps as shown by illumination of a horizontal plane (Figure 3), yet the sensed light level showed only modest differences (Figure 4). When plants are introduced in the model, the sensed light level between positions in and outside the plant row were large (Figure 4). Also for LEDs, after light penetration through the plant, hardly any light remained to illuminate the neighboring row (data not shown), suggesting each double plant row should contain a LED module for homogeneous illumination.


Optimizing illumination in the greenhouse using a 3D model of tomato and a ray tracer.

de Visser PH, Buck-Sorlin GH, van der Heijden GW - Front Plant Sci (2014)

Computed light intensity (W per sensor with 6 cm radius) at the trajectories of Figure 3, with and without light intercepting plants (plant positions indicated by arrows). For this simulation the HPS lamps had an arbitrary light output of 1000 W m-2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927125&req=5

Figure 4: Computed light intensity (W per sensor with 6 cm radius) at the trajectories of Figure 3, with and without light intercepting plants (plant positions indicated by arrows). For this simulation the HPS lamps had an arbitrary light output of 1000 W m-2.
Mentions: The light model computed considerable horizontal differences in light intensity within the crop. For HPS lamps without plants, the visual rendering seemed to indicate large intensity differences in the area between lamps as shown by illumination of a horizontal plane (Figure 3), yet the sensed light level showed only modest differences (Figure 4). When plants are introduced in the model, the sensed light level between positions in and outside the plant row were large (Figure 4). Also for LEDs, after light penetration through the plant, hardly any light remained to illuminate the neighboring row (data not shown), suggesting each double plant row should contain a LED module for homogeneous illumination.

Bottom Line: Results were compared to the standard configuration.Moreover, adaptation of leaf angles was incorporated for testing their effect on light use efficiency (LUE).The simulated leaf angles did not affect light absorption from inter-lighting LED modules, but the scenario with LEDs shining slightly upward (20(°)) increased light absorption and LUE relative to default horizontal beaming LEDs.

View Article: PubMed Central - PubMed

Affiliation: Department of Greenhouse Horticulture, Wageningen University and Research Centre Wageningen, Netherlands.

ABSTRACT
Reduction of energy use for assimilation lighting is one of the most urgent goals of current greenhouse horticulture in the Netherlands. In recent years numerous lighting systems have been tested in greenhouses, yet their efficiency has been very difficult to measure in practice. This simulation study evaluated a number of lighting strategies using a 3D light model for natural and artificial light in combination with a 3D model of tomato. The modeling platform GroIMP was used for the simulation study. The crop was represented by 3D virtual plants of tomato with fixed architecture. Detailed data on greenhouse architecture and lamp emission patterns of different light sources were incorporated in the model. A number of illumination strategies were modeled with the calibrated model. Results were compared to the standard configuration. Moreover, adaptation of leaf angles was incorporated for testing their effect on light use efficiency (LUE). A Farquhar photosynthesis model was used to translate the absorbed light for each leaf into a produced amount of carbohydrates. The carbohydrates produced by the crop per unit emitted light from sun or high pressure sodium lamps was the highest for horizontal leaf angles or slightly downward pointing leaves, and was less for more upward leaf orientations. The simulated leaf angles did not affect light absorption from inter-lighting LED modules, but the scenario with LEDs shining slightly upward (20(°)) increased light absorption and LUE relative to default horizontal beaming LEDs. Furthermore, the model showed that leaf orientation more perpendicular to the string of LEDs increased LED light interception. The combination of a ray tracer and a 3D crop model could compute optimal lighting of leaves by quantification of light fluxes and illustration by rendered lighting patterns. Results indicate that illumination efficiency increases when the lamp light is directed at most to leaves that have a high photosynthetic potential.

No MeSH data available.