Light Transmittance of Greenhouses

Zabeltitz, Christian von

doi:10.1007/978-3-642-14582-7_6

Cited by 4 publications

(7 citation statements)

References 10 publications

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“…The year-round cultivation concept presented here aims to work with the harsh northern climate and adapt to the natural conditions instead of trying to go against them. When the outside environment is not suitable anymore for cultivation, the plants can be transported inside modern greenhouses with transparent covers which present the best option to provide additional heating and supplementary lighting to the plants [10,110].…”

Section: Discussionmentioning

confidence: 99%

“…The amount of natural light reaching inside a greenhouse depends heavily on multiple factors including the building design [114,124], roof shape and inclination [110,115], location and orientation [135], the position of the supporting structures as well as hanging objects inside like pots or lamps [111,136], and the covering material of the greenhouse [116,117,137,138]. Weathering and aging of the glazing as well as other local factors like condensation, dust, snow accumulation, and buildings nearby can obstruct the light that enters a greenhouse [112].…”

Section: Discussionmentioning

confidence: 99%

“…Figure 4 provides the monthly average diffuse fraction of global horizontal radiation (G d /G h ) calculated from the extracted data (see Figure A3 for Iceland). Due to the influence of the atmospheric conditions on the solar spectrum, knowing the proportion of diffuse radiation in a place can be important as an indicator of the cloudiness [107] and help estimate the overall light transmittance into the greenhouse [110].…”

Section: Estimating Ppfd From Global Irradiancementioning

confidence: 99%

“…The amount of outdoor light that is transmitted into a greenhouse depends in great measure on the covering material properties together with the angle of incidence at which the irradiance arrives [110]. When the light reaches the surface, it is either reflected, absorbed, or transmitted through the material [111,112].…”

Section: Greenhouse Light Transmissionmentioning

confidence: 99%

“…To compensate for the shortcomings of this simplification, the calculations were done for different values of τ h,PAR (40%, 55% or 70%) selected to be within the range of those reported in different studies of various greenhouse materials and at various locations, obtained through simulations or from measurements [65,110,111,[114][115][116][117][118].…”

Section: Greenhouse Light Transmissionmentioning

confidence: 99%

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Enabling Year-round Cultivation in the Nordics-Agrivoltaics and Adaptive LED Lighting Control of Daily Light Integral

Velasco

2021

Agriculture

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High efficacy LED lamps combined with adaptive lighting control and greenhouse integrated photovoltaics (PV) could enable the concept of year-round cultivation. This concept can be especially useful for increasing the production in the Nordic countries of crops like herbaceous perennials, forest seedlings, and other potted plants not native of the region, which are grown more than one season in this harsh climate. Meteorological satellite data of this region was analyzed in a parametric study to evaluate the potential of these technologies. The generated maps showed monthly average temperatures fluctuating from −20 °C to 20 °C throughout the year. The natural photoperiod and light intensity also changed drastically, resulting in monthly average daily light integral (DLI) levels ranging from 45–50 mol·m−2·d−1 in summer and contrasting with 0–5 mol·m−2·d−1 during winter. To compensate, growth room cultivation that is independent of outdoor conditions could be used in winter. Depending on the efficacy of the lamps, the electricity required for sole-source lighting at an intensity of 300 µmol·m−2·s−1 for 16 h would be between 1.4 and 2.4 kWh·m−2·d−1. Greenhouses with supplementary lighting could help start the cultivation earlier in spring and extend it further into autumn. The energy required for lighting highly depends on several factors such as the natural light transmittance, the light threshold settings, and the lighting control protocol, resulting in electric demands between 0.6 and 2.4 kWh·m−2·d−1. Integrating PV on the roof or wall structures of the greenhouse could offset some of this electricity, with specific energy yields ranging from 400 to 1120 kWh·kW−1·yr−1 depending on the region and system design.

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Section: Discussionmentioning

confidence: 99%