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The main reason for applying microclimate control in greenhouses is to achieve optimal growing environment. Because of its complexity, excessive control in greenhouses can adversely affect the growing crops. Moreover, we need an optimal ambiental control to accomplish these complicated objectives, including low emissions and reduced production costs. This paper describes one practical approach to the real-time control system in a greenhouse. Control system considers internal and external ambient factors related to the regulation process. Control system cyclically reads the data from the sensors and implements appropriate response on the actuator, based on required greenhouse conditions. Most challenging was the design of the control algorithm for this kind of process, due to a complexity of influential greenhouse variables.

This paper aims to investigate the development of a floating artificial sustainable energy island at a conceptual design level that would enhance the energy independence of islands focusing on a case study on the island of Crete. This paper provides a baseline assessment showing the immense potential of wind and solar energy in and around Crete integrating the third significant renewable energy source (RES) of ocean waves into the energy island. The selection of the best location for the floating offshore platforms that compose the energy island is addressed through exploiting the great potential of the above-mentioned RES, taking into consideration criteria with regard to several significant human activities. To this end, the concept of an innovative floating modular energy island (FMEI) that integrates different renewable energy resources is proposed; in addition, a case study that focuses on the energy independency of a big island illustrates the concept referring to the substitution of the local thermal power plants that are currently in operation in Crete with sustainable energy power. Although focused on the renewable energy resources around Crete, the work of this paper provides a basis for a systematic offshore renewable energy assessment as it proposes a new methodology that could be used anywhere around the globe.

Green roof systems have become an important part in creating sustainable cities. They can provide a wide range of economic, environmental, and social benefits. The goal of this research was to quantify the thermal performance improvements from a green roof with mineral wool substrate installed on a school building in a humid subtropical climate. In-situ measurements during a summer period included heat fluxes through the green and reference roof, vertical temperature profile through both roofs, the local air temperature above roofs, and local meteorological parameters. Furthermore, the summer thermal performance of green and reference roof and the green roof cooling effect were evaluated concerning meteorological parameters using the Pearson correlation analysis. The results indicate that the green roof layers have improved thermal performance of the roof with respect to reduced conductive heat flow by 57% and delayed heat transfer. The maximum and averaged reference roof to green roof outdoor surface temperature difference was 27.5 degrees C and 5.5 degrees C, respectively. It was found that ambient temperature and relative humidity have a dominant role on the thermal performance of the green and reference roof, while solar radiation and ambient temperature present the key meteorological determinants of the green roof cooling effect.

The Republic of Serbia has a significant potential for the electricity production from solar energy, namely the floating photovoltaic (PV) systems, which are not exploited enough. Although there is a large interest in floating photovoltaic systems (FPVS) worldwide, studies related to the assessment of FPVS potential in this part of Europe have not been performed yet. This paper investigates, for the first time, the possibility of implementation of the FPVS on the six largest Serbian lakes and demonstrates the impact of geographical location on the energy output of the FPVS for the selected locations. The possibility of implementation is studied by simulating the energy output of FPVS using "PVGIS" tool. Energy production from the proposed FPVS, for selected locations, is discussed on a monthly and yearly basis. Installment of the FPVS on these water bodies can produce up to 8959 kWh of energy, while saves 164⋅10^6 m3/year of water from evaporation at the same time. In addition, the annual reduction of carbon dioxide emissions was analyzed and found to be up to 6.34 tons per year, which further implies with carbon credit potential of up to 9741 € in 20 years period. Drawn conclusions provides better understanding of FPVS and their applicability in the Republic of Serbia to ensure a sustainable, ecological friendly, secure and reliable supply of green energy, and further the used approach can be easily applied in other countries with similar geographical characteristics.