The increasing demand for energy, depletion of fossil fuels, rising global warming, and greenhouse gas emissions have stimulated the need for widespread development and adoption of renewable energy sources (RES) worldwide. Among these sources, solar energy has emerged as a major contender to meet the growing demand. It offers adaptable applications and provides an alternative to traditional energy sources. A brand-new application of solar panels is agrivoltaics. Agrivoltaics consists in installing solar panels above farming lands such as crops. The combination of solar energy production and farming on the same lands increases the overall yield of the land and brings several other opportunities. However, agrivoltaics is also very challenging. An improper installation of solar panels above crops may result in a dramatic drop of the farming yield. Thus, it is of major importance to understand how to maximize the solar energy production without harming the plants or decrease the farming yield. This master’s thesis focuses on the impact of agrivoltaic systems on the micro-climate close to the crop. The goal is to link the modified physical phenomena within an agrivoltaic system and their impact on the crops. The methodology is based on Computational Fluid Dynamics (CFD). The idea is to realize high fidelity simulations of the different physical phenomena and their coupling, and compare them to experimental data. Flow simulations coupled with radiative models and a surface model are realized in this perspective. The master’s thesis is divided in three parts. 1. Based on experimental data collected during three years at the EDF lab les Renardières, determine which physical phenomena impact the most the crop and what are the key parameters to study the growth of the plants. 2. Validate with experimental data from the atmospheric laboratory the SIRTA (Site Instrumental de Recherche par Télédétection Atmosphérique) of the engineering school Polytechnique, the radiative models and the surface model of the CFD software. 3. Study the impact of an agrivoltaic system on the identified physical phenomena with a simple geometry composed of one pitch of solar panel. The data study shows clearly that the plant temperature, the groundwater, and the radiation play crucial roles in the growth of the plant. A lack of radiation or groundwater will limit the growth of the crops. In addition, extreme temperatures can harm the crops. Consequently, this research project will firstly focus on capturing the impact of the solar panels on these three key parameters. Simulations are using a coupling of a 1D radiative model which is computationally fast and that can therefore be applied on a very large domain to compute the absorption of the atmospheric layers and the clouds, and a 3D radiative model which is able to capture the impact of an obstacle such as a solar panel. This coupling is validated for the shortwave radiation and the longwave radiation. Finally, full U-RANS simulations with the radiative models, the surface model and the - turbulence model are realized. The impact of the panels on the radiation field, the soil temperature, the specific humidity and on other fields such as the wind speed is well captured.

Folienmanagement ist von wirtschaftlicher Bedeutung im Freiland-Gemüsebau im Frühjahr. Aber die Prognose des optimalen Zeitpunktes der Abnahme von Plastik-Abdeckungen vom Bestand ist mit den bereits verfügbaren Mitteln zu ungenau, um die heutigen Anforderungen an die Produktionssicherheit zu erfüllen. Der bislang verwendete empirische Ansatz benötigt aktuelle Referenzmessungen unter den Abdeckungen, welche kostspielig sind. Das Ziel dieser Arbeit war es, die Grundlagen eines mechanistischeren Modellansatzes zu entwickeln, welcher auf dem physikalischen und biologischen Verständnis von Energiehaushalt, Pflanzenwachstum und den Prozessen der Qualitätsentwicklung unter den Abdeckungen beruht, um die zukünftige Produktionssicherheit zu verbessern. Entsprechende Feldversuche wurden durchgeführt, um Daten zum Pflanzenwachstum und Mikroklima unter und über der Abdeckung zu erhalten und neue sowie etablierte Untermodelle zu parametrisieren. Weiterhin wurden Laborversuche zum Verständnis z.B. der optischen Eigenschaften der Abdeckungen, Blätter und des Bodens ausgeführt. Außerdem wurde eine neue Methode zur Bestimmung des Blattflächenindex bei Kopfsalat und Kohlrabi geprüft und für die effiziente Erhebung der Pflanzendaten etabliert (Sandmann et al. 2013). Im Ergebnis können nun verschiedene Prozesse der Gemüseproduktion unter Abdeckungen besser verstanden und mit hinreichender Genauigkeit mathematisch beschrieben werden, z.B. Strahlungshaushalt (Graefe & Sandmann 2014) und Blattflächenwachstum. Die meisten Ziele der Arbeit wurden erreicht. Weitere Arbeit ist vor allem notwendig für die Modellierung der Lufttemperatur unter der Abdeckung und die Entwicklung eines mechanistischen Ansatzes zur Beschreibung der Pflanzenqualität. Hier konnte die Pflanzenqualität wegen der subjektiv beeinflussten Daten nur über einen empirischen Ansatz modelliert werden. Die übliche Erfassung der Pflanzenqualität sollte überdacht werden, um zukünftig möglichst objektive Werte zu erhalten. / Plastic film management is economically of importance for vegetable growing in the field in early spring, but the prediction of the best moment of removal of plastics from the crops is currently too imprecise to fulfill contemporary requirements in production safety. The broadly used approach for prediction is of empirical nature and is depending on current reference data from below covers, which are expensive to gather. The aim of this thesis was to develop the scientific foundations for a more mechanistic model approach, based on the physical and biological understanding of the energy balance, plant growth and plant quality formation process below plastic covers in order to increase future production safety. Field trials at three sites, with two species and several cover materials and removal strategies were carried out to gain data from plants and microclimate beneath and above covers for parameterization of new and established submodels. Additionally, laboratory experiments were performed to understand e.g. the optical properties of plastics, leaves and soil. Furthermore, a new method for determining leaf area index in lettuce and kohlrabi was adopted and established for a more efficient plant data collection (Sandmann et al. 2013). As a result, several processes of vegetable production using plastic covers are now better understood and can be described mathematically and sufficiently precise, e.g. the short wave radiation budget (Graefe & Sandmann 2014) and leaf area growth. Most, but not all aims of the thesis could be achieved. Further work will be necessary according to modeling of air temperature below the covers, leaf gas exchange and the development of a mechanistic approach for plant quality formation. Here, plant quality could only be modelled via an empirical approach, due to subjectively influenced data. Common plant quality data acquisition should be reconsidered to yield as much as possible objective values in the future.

The location of the site where the pioneers settled permanently was determined by the availability of water in the immediate environment. The Highveld contains fertile soils, a fine climate, and an abundance of water. The area has always been extensively used for crop and stock farming, but in general, mixed farming was practiced. The farmers depended on the availability of water, therefore their experiences, observations, weather forecasts, and conclusions, developed into a popular folk meteorology. Furthermore, environmental factors such as local topography, micro climate, hydrography, ground fertility, and the appearance of natural vegetation determined whether or not an area was suitable for permanent residence. The farmstead may be divided into three functional zones (the core-, extended-, and outer farmyard) that are joined by a canal network, used for irrigation and drinking water. The farmhouse and buildings, erected a stones throw away from the water source, served as a focal point for the activities of the farmer. The manipulation of the water source by obstruction of streams and the construction of water canals, weirs and water furrows, assisted the farmer in planning his activities and in using the water to his advantage. The settlement and development of the residence on the rural parts of the Highveld may be divided into three distinct phases. Firstly, the temporary trekboer phase, secondly the pioneer phase and thirdly the permanent settlement phase. The permanence of residence had a direct influence in the layout of the house, the method of construction, and the use of the available water supply. At first, the trekkers were content to reside in roof dwellings (their wagons and tents and a grass screen as their kitchen and a hut near a spring). The first houses were hartbieshuise and kapsteilhuise. The more permanent homesteads of the earlier settlers were a simple rectangular structure (pioneer house) with a saddle grass roof. With the introduction of galvanised iron sheeting, the house was expanded and developed into the veranda-, stoeproom- and a flat roofed rectangular house. This development resulted into a typical rural Highveld homestead. After the discovery of gold in the vicinity of the Witwatersrand, the first gold rush took place resulting in the proclamation of Johannesburg in 1886. Prospectors, mostly foreigners, descended upon the Witwatersrand. Housing took on a more planned structure resembling the late Victorian period of housing in England. The water supply and drainage systems were planned and improved, making it possible to provide running water to kitchens and bathrooms. This impacted firstly on the upper riches of society in the cities, later on the lower middle classes and lastly on the rural areas. European technology regarding the supply of hot pipe water and drainage systems changed the layout of the house. The cooking activity moved from outside behind a screen to a seperate room inside the house. Inevitable changes regarding collecting, storage, purpose, saving and drainage of household water took place. Between 1840 and 1910, evolutionary changes took place regarding sanitation, water supply and personal hygiene. Being part of a particular social class made certain facilities available to certain individuals. A rural Highveld dwelling rarely included sanitary facilities, instead dwellers had a more primitive wash basin in each room in which they washed daily. On a Saturday, a weekly bath was taken in a bathtub in the kitchen or bedroom. Trekkers simply relieved themselves outside. A revolution in sanitary habits and facilities became inevitable. The Victorian dwelling on the Highveld was built according to a standard plan, including a flush water system already in place. This was the ultimate manifestation of sophistication and civilization. The aim of this investigation is to identify the similarities and differences between the use of water by the pioneer, the poor people and the wealthy in their rural dwellings. Furthermore, information has been obtained regarding water usage and sanitation in the bathroom and kitchen in the rural dwelling to be useful in the area of historic architecture and the heritage of our water history. / Thesis (M.A. (History))--North-West University, Vaal Triangle Campus, 2008.

The location of the site where the pioneers settled permanently was determined by the availability of water in the immediate environment. The Highveld contains fertile soils, a fine climate, and an abundance of water. The area has always been extensively used for crop and stock farming, but in general, mixed farming was practiced. The farmers depended on the availability of water, therefore their experiences, observations, weather forecasts, and conclusions, developed into a popular folk meteorology. Furthermore, environmental factors such as local topography, micro climate, hydrography, ground fertility, and the appearance of natural vegetation determined whether or not an area was suitable for permanent residence. The farmstead may be divided into three functional zones (the core-, extended-, and outer farmyard) that are joined by a canal network, used for irrigation and drinking water. The farmhouse and buildings, erected a stones throw away from the water source, served as a focal point for the activities of the farmer. The manipulation of the water source by obstruction of streams and the construction of water canals, weirs and water furrows, assisted the farmer in planning his activities and in using the water to his advantage. The settlement and development of the residence on the rural parts of the Highveld may be divided into three distinct phases. Firstly, the temporary trekboer phase, secondly the pioneer phase and thirdly the permanent settlement phase. The permanence of residence had a direct influence in the layout of the house, the method of construction, and the use of the available water supply. At first, the trekkers were content to reside in roof dwellings (their wagons and tents and a grass screen as their kitchen and a hut near a spring). The first houses were hartbieshuise and kapsteilhuise. The more permanent homesteads of the earlier settlers were a simple rectangular structure (pioneer house) with a saddle grass roof. With the introduction of galvanised iron sheeting, the house was expanded and developed into the veranda-, stoeproom- and a flat roofed rectangular house. This development resulted into a typical rural Highveld homestead. After the discovery of gold in the vicinity of the Witwatersrand, the first gold rush took place resulting in the proclamation of Johannesburg in 1886. Prospectors, mostly foreigners, descended upon the Witwatersrand. Housing took on a more planned structure resembling the late Victorian period of housing in England. The water supply and drainage systems were planned and improved, making it possible to provide running water to kitchens and bathrooms. This impacted firstly on the upper riches of society in the cities, later on the lower middle classes and lastly on the rural areas. European technology regarding the supply of hot pipe water and drainage systems changed the layout of the house. The cooking activity moved from outside behind a screen to a seperate room inside the house. Inevitable changes regarding collecting, storage, purpose, saving and drainage of household water took place. Between 1840 and 1910, evolutionary changes took place regarding sanitation, water supply and personal hygiene. Being part of a particular social class made certain facilities available to certain individuals. A rural Highveld dwelling rarely included sanitary facilities, instead dwellers had a more primitive wash basin in each room in which they washed daily. On a Saturday, a weekly bath was taken in a bathtub in the kitchen or bedroom. Trekkers simply relieved themselves outside. A revolution in sanitary habits and facilities became inevitable. The Victorian dwelling on the Highveld was built according to a standard plan, including a flush water system already in place. This was the ultimate manifestation of sophistication and civilization. The aim of this investigation is to identify the similarities and differences between the use of water by the pioneer, the poor people and the wealthy in their rural dwellings. Furthermore, information has been obtained regarding water usage and sanitation in the bathroom and kitchen in the rural dwelling to be useful in the area of historic architecture and the heritage of our water history. / Thesis (M.A. (History))--North-West University, Vaal Triangle Campus, 2008.

The location of the site where the pioneers settled permanently was determined by the availability of water in the immediate environment. The Highveld contains fertile soils, a fine climate, and an abundance of water. The area has always been extensively used for crop and stock farming, but in general, mixed farming was practiced. The farmers depended on the availability of water, therefore their experiences, observations, weather forecasts, and conclusions, developed into a popular folk meteorology. Furthermore, environmental factors such as local topography, micro climate, hydrography, ground fertility, and the appearance of natural vegetation determined whether or not an area was suitable for permanent residence. The farmstead may be divided into three functional zones (the core-, extended-, and outer farmyard) that are joined by a canal network, used for irrigation and drinking water. The farmhouse and buildings, erected a stones throw away from the water source, served as a focal point for the activities of the farmer. The manipulation of the water source by obstruction of streams and the construction of water canals, weirs and water furrows, assisted the farmer in planning his activities and in using the water to his advantage. The settlement and development of the residence on the rural parts of the Highveld may be divided into three distinct phases. Firstly, the temporary trekboer phase, secondly the pioneer phase and thirdly the permanent settlement phase. The permanence of residence had a direct influence in the layout of the house, the method of construction, and the use of the available water supply. At first, the trekkers were content to reside in roof dwellings (their wagons and tents and a grass screen as their kitchen and a hut near a spring). The first houses were hartbieshuise and kapsteilhuise. The more permanent homesteads of the earlier settlers were a simple rectangular structure (pioneer house) with a saddle grass roof. With the introduction of galvanised iron sheeting, the house was expanded and developed into the veranda-, stoeproom- and a flat roofed rectangular house. This development resulted into a typical rural Highveld homestead. After the discovery of gold in the vicinity of the Witwatersrand, the first gold rush took place resulting in the proclamation of Johannesburg in 1886. Prospectors, mostly foreigners, descended upon the Witwatersrand. Housing took on a more planned structure resembling the late Victorian period of housing in England. The water supply and drainage systems were planned and improved, making it possible to provide running water to kitchens and bathrooms. This impacted firstly on the upper riches of society in the cities, later on the lower middle classes and lastly on the rural areas. European technology regarding the supply of hot pipe water and drainage systems changed the layout of the house. The cooking activity moved from outside behind a screen to a seperate room inside the house. Inevitable changes regarding collecting, storage, purpose, saving and drainage of household water took place. Between 1840 and 1910, evolutionary changes took place regarding sanitation, water supply and personal hygiene. Being part of a particular social class made certain facilities available to certain individuals. A rural Highveld dwelling rarely included sanitary facilities, instead dwellers had a more primitive wash basin in each room in which they washed daily. On a Saturday, a weekly bath was taken in a bathtub in the kitchen or bedroom. Trekkers simply relieved themselves outside. A revolution in sanitary habits and facilities became inevitable. The Victorian dwelling on the Highveld was built according to a standard plan, including a flush water system already in place. This was the ultimate manifestation of sophistication and civilization. The aim of this investigation is to identify the similarities and differences between the use of water by the pioneer, the poor people and the wealthy in their rural dwellings. Furthermore, information has been obtained regarding water usage and sanitation in the bathroom and kitchen in the rural dwelling to be useful in the area of historic architecture and the heritage of our water history. / Thesis (M.A. (History))--North-West University, Vaal Triangle Campus, 2008.

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