Sharif Digital Repository

In recent years, the issue of sustainability in the energy systems has attracted the attention of energy researchers. Using fossil fuels in common energy conversion systems cause environmental pollution, declining reserves of fossil resources and increase their prices because of the scarcity of fossil resources. Therefore, achieving the goals of sustainability necessitate using high efficiency energy conversion technology. Bio-inspired energy systems are one of the main candidates to improve energy conversion systems. The main target of this study is developing an optimal multi-generation energy system model, dynamically. MFC, Septic tank and Algae culture are integrated and produced power,... 

This current reseach concentrates on designing and evaluation of stand-alone alternative energy system which consists of a proton exchange membrane fuel cell system (PEMFC), a photovoltaic (PV) panel, a proton exchange membrane electrolyser and a hydrogen storage tank.. To establish the minimum capacity of the system components, a system sizing model is developed in MATLAB Based on meteorological and the electrical yearly demand data which are extracted from DEDM model. The accuracy of the sub models is checked by comparing the experimental measurements of the system components obtained from other literatures with model outputs. The evaluation is based on demand profile, investment costs,... 

Heating demand required for greenhouses is mainly met by fossil fuels. On the other hand, anxieties over usage of fossil fuels have led the societies to move toward renewable energies. With this in mind, the purpose of this research is to analyze using both solar energy for satisfying the heating demand of greenhouses and heat storage for compensating the intermittence of renewable energy.Considering the mentioned points, in the current research, a linear optimization framework has been developed for design and operation of energy systems including long-term heat storage to meet heating demand of greenhouses. The objective of this framework is to minimize annual cost. The developed method... 

The main purpose of this research is analyzing the energy stream of clean food production by using Iran's power plants sourced waste heat. In order to achieve this goal, at first, greenhouse heating demand model according to the type of crops and geographic location of greenhouse, heat transport from power plant to greenhouse model, and heat exchanger model is presented. Then, the potential of constructing clean greenhouse around power plants has been evaluated by using the concept of industrial symbiosis and by integrating greenhouse energy demand, waste heat transport, and heat exchanger models into industrial symbiosis concept framework and also by economical and geographical assessments.... 

Meeting the energy demand of agricultural greenhouses has turned out to be the most important challenge of greenhouse cultivation. In this study, it is proposed to use the concept of industrial symbiosis between agricultural greenhouses and biogas plants to face this challenge. The main purpose of the study is to investigate the potential clean greenhouse area that may be supported by the proposed symbiotic network, in order to provide a decision-making tool for the relevant policymakers. The methodology is based on the agent-based input-output matching economic analysis. The amount of biogas produced by poultry and cattle manure is estimated to be 0.6 (m3 / kg VS) and 0.47 (m3 / kg VS)... 

Given the growth of the world's population along with the increase in the percentage of urban population by 2050, the way of responding to food consumption will change in the future. Controlled Environment Agriculture will largely account for future food supply. Vertical Farming is one of these systems. But despite the efficiency of these systems in terms of land and water and also not being affected by weather conditions, the main challenge in these systems is the consumption of energy use per unit of crop production. The cost of energy is about 25 to 40 percent of the total costs. The purpose of this study is to develop an integrated dynamic model for the determination of vertical farm... 

The present study aims to reduce the carbon footprint of greenhouse products to provide a decision tool for sustainable development of greenhouses. In order to provide this decision tool, the impact of four scenarios or energy-efficient technology for greenhouse heating, including: combine heat and power system(CHP), new greenhouse covering material, industrial symbiosis, and solar collector on the carbon footprint of greenhouse products has been studied because one of the main factors in the release of carbon footprints of greenhouse products is the use of fossil fuels for greenhouse heating. Energy modeling has been used to estimate the amount of heating, cooling, and artificial lighting... 

Agriculture is one the most water consuming sections in the world and roughly 60% of water demand is dedicated for this purpose. A seawater greenhouse manages to combine fan and pad greenhouse with humidification-dehumidification desalination in order to achieve water production next to agriculture products using moister in air which was used for cooling. The most important aspect of a seawater greenhouse is the amount of produced water. Many research on the condenser type and materials have been conducted in order to achieve a better performance, suggesting the utilization of a low temperature water source for the condenser. In this research, using a thermodynamic correlations to model the... 

The purpose of this study is to develop a simulated model of a greenhouse using two different ventilation systems, a fan&pad system and an air-soil converter equipped with a sprinkler in order to compare the cooling performance of these two systems in hot seasons. The main focus of the analysis of the results is on how the temperature and humidity are distributed throughout the greenhouse space. In order to develop a three-dimensional model with computational fluid dynamics method, greenhouse simulation in Ansis software has been used. The development of ventilation model in the greenhouse is done by creating boundary conditions using optimal design. Also, to simulate soil-air conditioning... 

Industrial symbiosis(IS) is a promising approach toward sustainable development goals. Among common modeling techniques, agent-based modeling holds a special place in IS simulation due to its bottom-up nature. However, the role of essential technologies in supply chain of IS has been poorly studied in the literature. In this work, first, an agent-base model is developed based on economic and environmental incentives of IS stakeholders employing optimization and non-cooperative game theory. Then, essential technologies in each potential symbiotic relation are integrated into the model to investigate their impact. The result suggests, to facilitate IS through environmental policy making, on... 

CO2 capture and utilization (CCU) is a promising approach to reduce and control emissions from the industry and energy sector, while also creating new jobs and value-added products. However, one of the main barriers to the widespread adoption of CCU is the high investment and operating costs, which limit its implementation to mostly government-supported research projects. To overcome this barrier, structural optimization and identification of optimal routes and formation of industrial symbiosis networks are needed. In this research, we developed a comprehensive superstructure that includes sources and sinks (in a case study), CO2 capture and separation material and technology combinations... 

To meet the high energy demand in greenhouse cultivation, clean technologies have been suggested. This research provides a computational and modeling framework to examine the integration of three systems including a photovoltaic panel, earth_air heat exchanger, and industrial symbiosis, to produce three types of energy (electricity cooling, and heating) in a Venlo-type greenhouse. To estimate the minimum energy required to maintain environmental parameters in optimal plant conditions, an energy demand model was developed with the ability to consider the effect of energy stored in the ground. For a greenhouse in Tehran, the annual heating requirement was calculated as 432 kWh/m2 and 227... 

The combination of photovoltaic technology and Organic Rankine Cycle reduces the temperature of the solar panel and, on the other hand, generates separate electricity from excess heat. The reason for the use of the Organic Rankine Cycle is the low temperature of the heat source. It is not economical to use other cycles like steam Rankine cycle in low-temperature heat sources. To maximize the plant factor of the Organic Rankine cycle system, especially when there is not enough solar radiation, it is possible to utilize the flue gas heat recovery in office buildings and reduce the cost of electricity generation. In this project, the simulation of this system is carried out for the Energy... 

Increasing global demand for water, food, energy and the interdependency of these three nexuses increase the necessity of finding suitable solutions and making policies considering the impact of each nexus to the others. The aim of developing greenhouses is to produce high-quality food with high performance while the water consumption decrease. This comes along with huge amount of energy consumption. Solar greenhouse technology utilizes solar energy to decrease heating demand of greenhouse to zero. The greenhouse performance has a direct correlation with climate condition. This research has been conducted to present optimal design for solar greenhouses. Firstly, a solar passive design was... 

Relying on current fuels and technologies in vehicle industry in recent years has led to an enormous challenge such as air pollution, climate change and energy security. In the other hand, fossil fuel reservoirs are being depleted with an intensive rate. Nowadays, hydrogen, as a substitute for current fuels and hybrid, fuel cell and electric vehicles, as substitutes for current vehicular technologies are under research and development. Because of abundant advantages such as high efficiency and long cycle life, no depreciation for parts and scalability, fuel cell vehicles is of interest for many car manufacturers throughout the world and lots of them have demonstrated their prototype fuel... 

With the current demands in alternative methods of energy production and increased utilization of existing energy sources, microbial fuel cells have become an important field of research. In a microbial fuel cell, organic and inorganic compounds can be oxidized by microbial catabolism at the anode to generate direct electricity. A kind of microbial fuel cell (MFC) is sediment microbial fuel cell (SMFC) consists of an anode electrode embedded in the anaerobic sediment and a cathode electrode suspended in the overlying aerobic water. microorganisms produce electrons by oxidation of organic or inorganic compounds in the sediment at anode electrode, while oxygen is reduced in the water by... 

One of the processes for energy carriers creating from biomass is Gasification process. The main products of this process are hydrogen and carbon monoxide. Output of this process has an average calorific value and sensible heat. Using sensible heat for preheating inlet air is one the ways for enhancement gasification processes. In this study gasification process is modeled as zone modeling. The humidity, pressure and air preheating effects on output gas composition and system’s layout were investigated. In the first and second scenario comparing the shifting of gas blower from downstream to upstream of gasification reactor is studied. It is showed the average temperature and number of... 

The purpose of this research is developing an analytical and decision-making tool that examines the interactions between greenhouse energy demand and yield production. Greenhouseholders can use the analytical tool to design and operate existintg and newly built greenhouses in an optimal way. Becides, the decision making tool helps planners and policymakers to improve the performance of greenhouses and extend greenhouse cultivation with respect to their economic or environmental objectives.In order to develop this decision making tool, existing models for greenhouses have been investigated and various algorithms have been combined to develop an integrated energy demand-plant growth model. The... 

The population growth and scarcity of resources such as water and land make the food security as one the most important critical priorities in the world. Development of food production in greenhousesinstead of the traditional agriculture in rural areas is an efficient and applicable approache to reach food security and optimum use of water resources. However, this requires more capital. An important part of this cost is related to the cost of energy supply for heating and cooling in order to provide a suitable condition for the growth of plants. Optimal design of a rural energy supply and optimal operation of existing greenhouses to maximize the benefit of the greenhouse owners and to... 

Incereasing trend of energy consumtion and limited sources of conventional energy carriers causes an increase of carrier’s price and as a result nowdays more attention is focused on unconventional energy carriers. One of these unconventional carries is flare gas, which has a high potentioal for recovery.There are different methods for flare recovery and electricity generation is one of the most economic solutions for flare gas. The purpose of this project is technical and economical investigation of electricity generation using flare gas and to study impact of important parameters on economy of design. Reciprocationg engin, gas turbine and steam turbine are chosen for investigation. Capital...