Grid uncertainty, the availability of renewable sources, and power shortages are significant drawbacks for hybrid renewable energy systems. To address these issues, a two-step multi-objective optimization approach with a rule-based battery sizing can be used to identify the best energy management scenario, and appropriate energy storage solutions can help mitigate these disadvantages. In this study, a high-rise residential building was modeled using EnergyPlus software. A variable temperature setpoint for the heating, ventilation and cooling (HVAC) system was implemented to maintain thermal comfort and achieve energy savings. Simulation results were then imported into Python, where a multi-objective optimization approach was applied to integrate renewable energy solutions. A multi-criteria decision-making (MCDM) method was used to identify the optimal solution among various alternatives. The findings show that battery sizing is crucial for optimizing the hybrid energy system, as excess electricity can be sold to the grid. Additionally, the study found that the annual total cost of the optimized hybrid renewable energy system for renewable energy generation in three selected cities is $0.18/kWh, $0.2/kWh, and $0.17/kWh for Tabriz, Tehran, and Yazd, respectively. Moreover, the proposed hybrid renewable energy system (HRES) for Tabriz, Tehran, and Yazd can potentially sell 30%, 24%, and 23% of their annual renewable energy generation to the grid.

Phase change materials (PCM), thermoelectric generators (TEG), and nanofluids are popular methods investigated for improving conventional photovoltaic thermal (PVT) systems. These methods are particularly used in warm climates where high temperatures negatively impact photovoltaic (PV) power output and energy efficiency. This experimental study evaluated the effects of 32 degrees C melting point PCM and TEG integration on PVT units, as well as 42 degrees C melting point PCM and nanofluid incorporation on concentrated PVT (CPVT) units. Technical, exergetic, and economic performance were compared using a small-scale PVT module. Low-cost commercially available materials were used to construct all PVT units. Industrial metal waste was introduced to enhance the thermal conductivity of paraffin wax and salt hydrate PCMs. The results indicated that applying PCMs, porous media, and concentrator plates increased energy generation, potentially offsetting their higher initial cost and achieving an energy cost of approximately $0.135/kWh. However, TEG and nanofluid implementation remained uneconomical, leading to a 15-35 % increase in energy cost. The water-based CPVT unit, enhanced with paraffin wax and copper fins, demonstrated the best technical performance. This unit achieved electrical, thermal, and exergy efficiencies of approximately 15.5 %, 37.4 %, and 16.7 %, respectively, with more than a 20 % reduction in cell temperature. The study also revealed that severe structural changes caused by corrosion of metallic materials in hydrated PCMs could alter the melting point by more than 30 %. This change negatively impacts heat storage capacity. Conversely, incorporating metal chips in non-hydrated PCMs improved the time to reach the melting point state by 30-60 minutes.

The progression of data-driven methods has been expediting within the past few years, and the application of machine learning methods in relation to load forecasting, energy consumption optimization, and predictive control models has been expanding as well. In that matter, several investigations have attempted to promote the energy-saving potential of building energy consumption due to the optimization of influential parameters. Various machine learning methods have been utilized using different training datasets such as environmental parameters, geometrical characteristics or occupancy profiles, etc. However, the impact of heating, ventilation and air conditioning (HVAC) setpoint temperature in combination with other parameters has been infrequently investigated. In the present study, a neural network approach has been utilized to achieve thermal comfort-oriented optimized load to implement as input data for sizing renewable energy hybrid systems due to a sustainability point of view. In that matter, the required training data set was acquired due to building energy model's (BEM) results from Energyplus Software. The outdoor dry-bulb temperature, the relative humidity, thermal comfort, and HVAC equipment setpoint temperature were considered as the training set's key features. The results revealed that the energy-saving potential can be reached at 4.7% and 64% for hot and cold seasons, respectively, which indicates a significant opportunity for HVAC load optimization. Moreover, the economic and environmental analysis was performed on the optimized hybrid renewable energy system.

The majority of existing water is saline water and it is crucial to find approaches and technologies to desalinate water in an efficient and reliable manner. Solar energy can be applied in desalination systems in order to provide required heat or generate needed electricity by using PV modules. Applying solar energy instead of fossil fuels leads to more environmentally benign technologies in desalinating saline water. Due to the severe worldwide water crisis, precise comprehension of desalination methods can pave the way toward potable water achievement at reasonable cost. In this paper, a comprehensive literature review is accomplished on various types of desalination systems and applications of solar energy in these technologies. Based on the reviewed studies, solar energy is a preferable source of energy for fresh water production with lower greenhouse gases emission and high operation reliability.

During the last decade, serious issues such as energy demand, depletion of fossil fuels and their environmental impacts draw attention towards renewable energy sources. In addition, the energy supply chain of Iran is deeply reliant upon fossil fuels. Further obstacles such as electricity blackouts in the hot season and future energy security require us to address these issues. For this reason, the growing consensus is to dominate a sustainable energy system on the grounds of energy, especially renewable energies, with low emission and pollution. The mean annual solar radiation in Iran is 2200 kWh/m2 which is greater than the worldwide average, due to locating on the world's Sun Belt. The total installed capacity of solar energy in Iran is not significant, however, it is growing annually. .Moreover, the Persian Gulf coasts, could provide the possibility of using the tidal energy of the ocean as well as the Caspian Sea coast which are suitable sites for thermal energy. Currently, 550 MW of renewable energy is being built in Iran and the installed capacity of renewable energy has reached 575 MW. Renewable energy has also led to the employment of 47,321 people directly and indirectly in the country. The installed capacity of Iran’s wind power is about 259 MW (45% of total renewable energies installed capacity), which is mostly located in Manjil and Roodbar. The biogas energy in Iran is mainly produced from domestic and industrial sewage/waste, animal waste, and agricultural product waste.

Since a high photovoltaic panel (PV) temperature impacts the electrical output power, especially in tropical countries, the use of some cooling methods such as fluid flows, phase change materials (PCMs), and porous media has been suggested as an attractive option. In this study, these methods are integrated experimentally; a novel low-cost porous medium is developed using aluminum shavings, considered as waste materials in some industries, to increase the thermal conductivity of the phase change material. Then, the combination of this porous medium with salt hydrate is added to the water-based photovoltaic-thermal (PV/T) system; the electrical, thermal, and exergy efficiencies of the units are measured in July and December. The results of this research show that the photovoltaic-thermal unit, integrated with phase change material and porous medium, would have a high cooling performance by reducing the average temperature of the photovoltaic panel. The 24 degrees C reduction would augment the electrical efficiency by 2.5%, compared to solo PV, in the warm month. Also, it is found that, by using a porous medium, the melting time of the phase change material decreases by about 19%-25%. This method yields a maximum of 4.34% exergy efficiency improvement, compared to the single photovoltaic unit. (c) 2020 Elsevier Ltd. All rights reserved.

Increasing the production of energy in line with industry development, transportation, and life quality improvement is an interesting topic needs to be addressed. Energy policymakers and researchers have aimed at energy management, particularly by improving energy systems performance. This review paper explains the rising interest of thermoelectric technology and applications. Nowadays, thermoelectric technology such as thermoelectric generators (TEGs) and thermoelectric cooling systems (TECs) provide heat loss recovery of thermodynamic units for power production of remote areas. Unlimited solar energy can also be employed for thermoelectric power production. This paper describes the principles of thermoelectricity and presents an explanation of current and upcoming materials. Developed models and various performed optimization of thermoelectric applications by using non-equilibrium thermodynamics and finite time thermodynamics are discussed as well. Additionally, a number of topical applications and energy resources are introduced. The main goal of this study is to give a clear overview of thermoelectric technology and applications.

Rural electrification challenges in Iran are the most important obstacle to achieve electricity access for the entire population. The current study focuses on finding an optimal renewable energy system to meet the load of a small village by renewable resources. This village faces frequent power outages, common in many far-off villages in Iran. A hybrid photovoltaics/wind turbine/biogas generator/fuel cell renewable energy system is proposed and analyzed for both stand-alone and on-grid application. Fuel cells are used alongside a hydrogen tank, batteries, and a reformer or an electrolyzer, to act as storage devices and backup component. The main goal is to find an optimal configuration that can meet the electricity demand and be satisfactory from both an economic and environmental point of view. The results indicated that using solar, wind and biogas is the most affordable method and that adding fuel cell to this configuration would increase costs by 33–37%, but also improve system flexibility. Using a reformer is more efficient and about 6% less costly, but also creates more pollution. The cost of energy for a stand-alone system with reformer was calculated to be 0.164 to 0.233 $/kWh, while the on-grid system cost of energy was 0.096–0.125 $/kWh.

The major logics resulting in hydrogen production can be mentioned as fossil fuel depletion and climate change. In this way, hydrogen is produced with the help of numerous processes based on traditional and alternative energy resources like coal, natural gas, wind, solar, biomass, and geothermal energy. Over the past decade, the attention of research institutions and industry has been drawn to hydrogen, inspired by developments in renewable energies. Hydrogen production can be considered as an exceptional choice to make complete utilization of the renewable energy. Among diverse technologies, hydrogen production based on geothermal energy offers great promise. In this paper, initially a concise summary of present and advancing hydrogen production technologies is presented, and secondarily a comprehensive review of research associated with hydrogen production based on geothermal energy is provided. Thirdly, the process descriptions of geothermal-assisted hydrogen production coupled with its technical, economic, and environmental aspects are addressed. Finally, comparative assessments of costs and environmental aspects related to hydrogen production based on different energy sources have been performed. In accordance with the results, the geothermal-assisted hydrogen production cost based on electrolysis is competitively lower than other sources like wind, solar thermal coupled with natural gas, solar PV, and grid. Also, the same behavior can be seen for geothermal-assisted hydrogen production cost based on thermochemical process.

The renewable energy can be utilized to satisfy the energy demand. Moreover, the solar energy as the most abundant energy resource among renewable energies plays a crucial role to provide the energy demand. The BIPV (building integrated photovoltaics) systems can be considered to supply the required energy demand from renewable sources. The essential advantage of BIPV systems is that they can be utilized as building component such as roof, window, shading systems and building facade and they can generate electricity simultaneously. Even though the photovoltaic technologies have been improved within past few years, however the utilization of the BIPV systems will be considered expensive. For this reason, the payback period calculation is considered a vital parameter in evaluating the BIPV systems. In this study, the overall energy consumption for producing one m2 of a mono-crystalline photovoltaic module is calculated 1334 kWh. Additionally, the photovoltaic module data for three companies were investigated and the annual energy productions for one m2 of each company’s product were obtained. The results showed that the average energy payback time for 270 and 280 watt modules are 5.565 and 5.254 respectively. Moreover, the energy payback time for 290, 325 and 340 watt modules were calculated 4.903, 5.437 and 4.965 respectively.

In the present study, enhancing the heat transfer is experimentally investigated by the electro-hydrodynamics (EHD) through a single-pass air-cooled PV/T (Photovoltaic/Thermal System). The corona wind increases the heat transfer coefficient by producing a secondary flow and vortex, and consequently, increases the PV/T system efficiency. The effects of the corona wind are studied by changing the voltage values and the flow rates in the air channel. The results show that the corona wind is effective on enhancing the system performance; so that the heat transfer coefficient increases by 65% in natural flow regime by applying 11 kV voltage in the pilot setup. Totally, the thermal efficiency of the PV/T system increases up to 28.9%. Also, the effects of corona wind are studied by changing the amount of the applied high voltages and flow rates. (C) 2018 Elsevier Ltd. All rights reserved.

The purpose of the present study is to investigate the thermal performance of a photovoltaic/thermal system, integrated with phase change materials in porous medium. For this purpose, a metal foam was employed as porous medium and the performance of five different PCMs, as organic and inorganic, were examined as well. Moreover, the effects of different key parameters such as the mass flow rate, solar irradiance, inlet water temperature and inclination were studied. Finally, the simulation results were compared with a water-cooled photovoltaic/thermal without incorporating PCMs and porous medium, and thermal performance of the three PV/T cases were reported. The highest thermal efficiency of the system was reported as 83% in case of 0.02 kg s(-1) mass flow rate and using Paraffin C22 as the storage material. In addition, the incorporation of porous medium resulted in better temperature distribution, and the porosity of 0.8 was resulted in higher thermal performance. Furthermore, the results were validated with an experimental study, and good agreement was reported. At last, the exergy analysis was applied on the system, and the results showed that the exergy efficiency of the PV/T module with metal foam filled with PCM was 16.7%.