Modeling
S. Mirzamohammadi; A. Jabarzadeh; M. Salehi Shahrabi
Abstract
IntroductionThe increasing global population on the one hand and limited water and soil resources on the other hand, contribute to the need for the supply of agricultural products by adopting modern methods. One of the modern methods of farming is the cultivation of products in commercial greenhouses. ...
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IntroductionThe increasing global population on the one hand and limited water and soil resources on the other hand, contribute to the need for the supply of agricultural products by adopting modern methods. One of the modern methods of farming is the cultivation of products in commercial greenhouses. Despite favorable performance of greenhouses in the agricultural sector, high demand for direct and indirect energy is among the main considerations of developing them because the energy supply of greenhouses has the highest influence on the performance of greenhouses, quality of products, and market price of products. In this study, the energy supply of greenhouses in the case of using renewable resources is done in a grid connection state. Trading energy with main grid is enabled. Decision-makers’ objective is determining the optimal number of renewable resources and energy storage units for the purpose of income maximization.Materials and MethodsBasically, the supply of energy for greenhouses or in other terms supply of electric, cooling, and heating loads required by greenhouses is intended to cover lighting, internal temperature, emission of CO2, and relative humidity. Since many greenhouses have proper access to the main grid for the supply of their demanded load, the problem seeks maximum use of renewable energy rather than buying power from the grid for supplying the loads which greenhouses need to its secure revenues. To this, mathematical modeling has used to determine the optimal number of energy sources and storage units that revenues of using renewable energy resources be optimized based on existing limitations. These limitations include balancing generation and consumption of thermal and electrical power in each hour, logical relationship between charging and discharging of batteries, limit of power generation of renewable sources in each hour of the day and the level of capital available for investment.Results and DiscussionBased on the collected data, 9 different issues have been defined in terms of the proportion of costs of solar energy and wind energy and the proportion of purchasing and selling price of power. The obtained results suggest that in the case of equality of investment and maintenance costs of solar and wind energies, the use of wind energy rather than solar energy will be justified. The most significant reasons for this is considering proper conditions of wind speed which causes its inclusion in optimal solution of the problem since using solar energy during nightly hours is impossible. In addition, in the case of the equality of above costs, when purchasing and selling price of power cost is the same, the generated energy is completely used in the greenhouse. In the case of increasing the selling price, energy supply to the main grid will be economically justified. Since investment and maintenance costs of wind power are two times and 1.5 times higher than those of solar energy, using wind energy is cost-effective.ConclusionThe results suggest that in the case of an equal price of selling power to the grid and buying power from it, all of the energy will be consumed in the greenhouse. In the case of an increase in selling price, the supply of energy to the main grid will be economically justified. In addition, the results imply the significant effect of geographic conditions of the region, since sometimes concurrent use of renewable energies is unjustified. Since the lack of supply of energy to greenhouses significantly influences the cultivation of products, considering the cost of lack of energy supply in modeling is one of the contributions of the present study. Another significant aspect of the study is the generalization of modeling from the greenhouse to greenhouse complexes. To do so, using the notion of micro-hub for greenhouses and their management will be useful.
Agricultural systems engineering (greenhouse, fish farming, mushroom production)
H. Faridi; A. Arabhosseini; Gh. Zarei; M. Okos
Abstract
In this research, an attempt was made to utilize an Earth-Air Heat Exchanger (EAHE) system as a source of shallow geothermal energy to provide thermal demands of a commercial greenhouse located in Alborz province, Iran. The degree-day index was applied to estimate the EAHE system’s potential to ...
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In this research, an attempt was made to utilize an Earth-Air Heat Exchanger (EAHE) system as a source of shallow geothermal energy to provide thermal demands of a commercial greenhouse located in Alborz province, Iran. The degree-day index was applied to estimate the EAHE system’s potential to meet the thermal requirements of the greenhouse including cooling and heating demands. The results indicated that this region needed more energy to reach to the relevant temperature inside the greenhouse for the heating demand comparing to the cooling one. The average potential of the EAHE system based on the degree-day index was 10.76ºC for increasing temperature in the cold and 17.96ºC for decreasing temperature in the warm season. This means that the EAHE system was capable of supplying the greenhouse thermal demands in this area according to the calculated values of Heating Degree-Day (HDD) and Cooling Degree-Day (CDD). This method would be beneficial in monitoring and optimizing plant growth conditions as the best crop type or cultivation selection which in turn can help in irrigation and fertigation management of the crop grown.
Z. Khosrobeygi; Sh. Rafiee; S. S. Mohtasebi; A. Nasiri
Abstract
Introduction Increasing the production efficiency is an important goal in precision farming. The use of precision farming requires a lot of labor work. Also, due to the risk of agricultural operations, it is not recommended to do it directly by humans. Therefore, it is necessary for agricultural operations ...
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Introduction Increasing the production efficiency is an important goal in precision farming. The use of precision farming requires a lot of labor work. Also, due to the risk of agricultural operations, it is not recommended to do it directly by humans. Therefore, it is necessary for agricultural operations to be carried out automatically. For this reason, the application of robotics in agricultural environments, especially in the greenhouse, is increasing. The first step in automatic farming is autonomous navigation. For autonomous navigation, a robot must be the ability to understand its environment and recognize its position. In other words, a robot must be able to create a map of an unknown environment, locate itself on this map and finally plane for the path. This problem is solvable by Simultaneous Localization and Mapping (SLAM). The SLAM problem is a recursive estimation process. In the other words, when a robot moves in an unknown environment, mapping and localization errors increase incrementally. To reduce these two errors, a recursive estimation process is used to solve the SLAM problem. Materials and Methods In this research, two webcams, made by Microsoft Corporation with the resolution of 960×544, are connected to the computer via USB2 in order to produce a stereo parallel camera. For this study, we used a greenhouse that was located the Arak, Iran. Before taking stereo images, a camera path was designed in the greenhouse. This path may be either straight or curved. The designed path was implemented in the greenhouse. The entire path traversed by a stereo camera was 32.7 m and 150 stereo images were taken. Graph-SLAM algorithm was used for Simultaneous Localization and Mapping in the greenhouse. Using the ROS framework, the SLAM algorithm was designed with nodes and network for connecting the nodes. Results and Discussion For evaluation, the stereo camera locations, every step was measured manually and compared with the stereo camera locations that were estimated in the graph-SLAM algorithm. The position error was calculated through the Euclidean distance (DE) between the estimated points and the actual points. The results of this study showed that, the proposed algorithm has an average of error 0.0679412, standard deviation of 0.0456431 and root mean square error (RMSE) of 0.0075569 for camera localization. In this research, only a stereo camera was used to prepare a map of the environment, but other researches have used multiple sensor combinations. Another advantage of this research related to others was created a 3D map (point cloud) of the environment and loop closer detection. In the 3D map, in addition to determining the exact location of the plant, the height of the plant can also be estimated. Plant height estimate is important in some agricultural operations such as spot spray, harvesting and pruning. Conclusion Due to the risk of agricultural activities, the use of robotics is essential. Autonomous navigation is one of the branches of the robotics. For autonomous navigation, a map of environment and localization in this map is need. The purpose of our research was to provide simultaneous localization and mapping (SLAM) in agricultural environments. ROS is a strong framework for solving the SLAM problem. So that, this problem can be solved by combining different nodes in ROS. The method depended only on the information from the stereo camera because stereo camera provided exact distance information. We believe that this study will contribute to the field of autonomous robot applications in agriculture. In future studies, it is possible to use an actual robot in the greenhouse with various sensors for SLAM and path planning.
D. Momeni; M. H. Rahmati
Abstract
Temperature and humidity are two important parameters affecting the quality and quantity of greenhouse products so two double greenhouses were manufactured in 3.5, 40 and 11 m in height, length and width respectively in agricultural research center of jiroft and kahnooj to study these effects. Both of ...
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Temperature and humidity are two important parameters affecting the quality and quantity of greenhouse products so two double greenhouses were manufactured in 3.5, 40 and 11 m in height, length and width respectively in agricultural research center of jiroft and kahnooj to study these effects. Both of greenhouses are similar in materials, final height, gutter height, covering and field operation but in one of them one heating system, two ventilation fans and one wooden pad were assembled and temperature and humidity besides yield were registered in both of them. The results showed that temperature changing trend inside and outside of the unheated greenhouse were in same phase and this isn't suitable in cold night so the greenhouse with heating system had more yield and picking cucumber fruit numbers than another. Therefore it is necessary to be heated by artificial systems. Because of rapid relative humidity changing in outside of greenhouse in the end of the season, the efficiency of fan and pads cooling system is so low then using of evaporating cooling systems such as fans and pad wasn't proposed and recommend to optimize the temperature by ventilation and shading the greenhouse and in hot days production will be cut.