Iranica Journal of Energy & Environment
Volume:12 Issue: 4, Autumn 2021

Hydrogen energy has the advantages of low carbon and cleanliness, high energy density, and high conversion efficiency; it is expected to play a pivotal role in Eastern Asia and the MENA region’s energy transition. The research status and development prospects of various technologies in hydrogen production, hydrogen storage, and hydrogen use are analyzed. On this basis, specific technical paths for developing renewable energy and integrated energy service parks coupled with hydrogen energy are proposed. Solid polymer electrolyte (SPE) electrolysis hydrogen production and solid material hydrogen storage are the most potential development in directions of hydrogen production and hydrogen storage. Technologies such as hydrogen fuel cell and natural gas hydrogen mixture in the hydrogen use link should be simultaneously promoted. The organic combination of wind/light-abandoned hydrogen production by electrolysis of water, wind power/photovoltaic off-grid hydrogen production with fuel cell power generation, hydrogen refueling station supply, methanol production, and natural gas hydrogen mixing technology would effectively solve the uneconomical and transportation difficulties of renewable energy hydrogen production. At the same time, hydrogen energy can realize the interconnection of multiple energy networks, and its application prospects in the future integrated energy service parks are very broad.

In the present work, the statistical analyses are presented to study the economic indexes of Net Present Value (NPV) and Simple Payback Period (SPB) as response functions for the Combined Cooling, Heating and Power (CCHP) system. The CCHP performance is simulated with the aid of thermodynamic modeling, and also economic equations are presented for economic simulation.  An attempt is made to study the effect of some economic factors (interest ratio, fuel cost, lifetime, and electricity sell price) on the system’s responses. Based on the Design of Experiment analysis, regression models are presented to quantify the effects of these parameters on the Net Present Value and Simple Payback Periods. This novel approach is developed utilizing the response surface methodology (RSM) based on the central composite design (CCD) method.  Sensitivity analysis of the economic parameters was also examined in this research. Optimal values of these parameters were obtained for the two economic indexes as response functions.

Glass plates have been commonly used as collectors’ covers due to technical feasibility, high transmissivity in shortwave solar irradiation, and low transmissivity in long-wavelengths. However, they are vulnerable to stones and hail. Plastic plates have high transmissivity in shortwaves but also have transmission bands in the middle of the thermal radiation spectrum. The current study represents an experimental assessment of different covering strategies, including single acrylic-cover, single glass-cover, double glass- acrylic cover, and double glass-cover. Two solar air heaters (SAHs) prototypes were constructed for this study. The acquired experimental runs illustrated that the single glass-covered SAH represents higher thermal performance than the single acrylic-covered SAH due to the lower transmissivity of glass plates in long wavelengths. The double-covered SAHs have higher performance than the similar single-covered SAHs. In the double-covered SAHs, the convective-radiant heat loss is reduced. However, increasing the cover number improves the radiant resistance to solar irradiation and reduces the collector performance when solar irradiation is insufficient and the absorber temperature is low, especially at the beginning of daytime hours. The SAH using a double-glass cover is preferable; however, the heat dynamics of the double glass- acrylic-covered SAH are so close to the double glass-covered one, and the acrylic plate is more resistant to harsh ambient conditions.

The turbofan engines are one of the constitutes significant components of the aero engines. In this study, the thermodynamic modeling of the TF30-P414 turbofan engine is developed and validated with reference values. The aims of this research are to determine the effect of the changes in the thrust, fuel mass flow rate, and thermal efficiency with changes of the flight-altitude (H) and the flight-Mach number (Ma). Then, the changing of the exergy efficiency and exergy destruction rate were investigated. The results show that between the different components of the engine in different flight circumstances, the highest exergy destruction occurred in the combustion chamber and the lowest exergy destruction occurred in the nozzle. Also, optimization with the objective function of finding optimum flight conditions to find the highest exergetic efficiency in the flight-Mach number of 1.2 to 2.2 and the flight altitude of 10,000 to 15,000 meters. The results of this optimization reported that the maximum exergetic efficiency happened to the conditions of H=11236 meters and Ma=1.944 with an amount of 32.64%.

The adhesion of metal ions from wastewater to surface of a material in an adsorption process had proven to be effective for remediation of wastewater before discharge. There is a growing demand to utilize alternative low-cost adsorbents for the removal of heavy metals from galvanic wastewater in most developing countries. Cow bones are cheap, readily available and can be sourced locally from slaughterhouses and abattoir. Therefore, their use as an alternative adsorbent for remediation of galvanic wastewater had to be assessed. In this study, the efficacy of cow bone char (CBC) was assessed for simultaneous heavy metal ions removal from real life galvanic wastewater in a competitive adsorption process. The galvanic wastewater was characterized using atomic adsorption spectrophotometry while the CBC was characterized using X-ray Fluorescence (XRF), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR). Batch experiment was performed to determine the effect of adsorbent dose, contact time and agitation speed on the removal efficiency of heavy metal ions from the galvanized wastewater. The concentrations of Mn2+, Fe2+, Zn2+, Pb2+ and Cr2+ in the raw wastewater exceeded the WHO and EPA standards. The adsorbent revealed a significant distribution of well-developed porous, rough surfaces with cracks characterized by different functional groups for the efficient adsorption process. The optimum adsorbent dose for all the metal ions was 0.04 g/100 mL at an optimum contact time of 60 minutes except for Fe2+ with optimum contact time of 20 minutes, and agitation speed of 150 rpm. The maximum metal removal efficiencies obtained for Mn2+, Fe2+, Zn2+, Pb2+ and Cr2were 99.7%, 100%, 99%, 90% and 85% +, respectively. The average adsorption capacity for Mn2+, Fe2+, Zn2+, Pb2+ and Cr2+were 0.44 mg/g, 26.7 mg/g, 78.5 mg/g, 0.133 mg/g for and 10.36 mg/g, respectively. CBC offers efficient and cost-effective removal of selected metal ions from galvanized wastewater.

Windows in the building are the biggest elements of heat loss through convective heat transfer. The purpose of study is to select appropriate dimensions for windows relative to shell and appropriate glazing for windows, in order to achieve optimal pattern to reduce energy consumption. The research method is based on the simulation and research tool is DesignBuilder software. Therefore, amount of natural gas consumed annually in the studied building was received from the National Iranian Gas Company and then the basic research was modeled by software and after converting unit from kWh to m3 and validating simulation results. In the next step, the range of 20% to 80% of window-to-wall-ratio, types of glazing and window height is considered and through parametric optimization, all conditions in the windows are simulated and analyzed for sensitivity index. The calculations confirm that in an intermediate residential building with a rotation of 12 degrees to the southeast in Tabriz, by reducing window-to-wall-ratio from 50% to 20% and replacing triples-glazed-glazing with a low-emission coating filled with argon gas with a transparent single-glazed glazing and UPVC frame and a canopy with a depth of 48cm and windows height of 1.5m, the heat losses were reduced by 60.34% and 75.24%, respectively.

The Photovoltaic modules installed on the surface of the water are naturally cooled, reducing the loss of thermal power generation. Floating photovoltaic systems (FPVS) combine existing photovoltaic systems with a floating structure to generate clean energy. To meet the growing electricity demand, FPV systems will be integrated alongside existing dams to enhance existing power sources. The results indicate that the investment toward installing FPV systems over the dams’ reservoirs leads to a significant improvement in the overall system reliability minimizes load curtailment, and could potentially add more flexibility to the operator to dispatch power generated by hydropower plants during peak demands. The execution of the Karun-4 FPV power plant with an annual production of 16758969 kWh of energy has reduced the water evaporation of the dam's reservoir water and after eight years and four months, the investment cost was returned and its nominal performance is 81.7 percent.  Adding a floating solar power plant with 10% of the lake reservoir cover of six dams saves 70.7 million cubic meters of water per year. This amount of fresh water is enough to meet the annual needs of one million people.

Today’s energy consumption is one of the most important causes of pollution around the world. Considering the building sector consumes the most energy, it should be seriously considered. In order to provide thermal comfort inside a building, energy is consumed, which can be managed using tools such as louvers that allow solar radiation to pass through the windows while reducing the amount of consumed energy. The goal of this paper is to find the optimal features for shading device of fixed louvers for the east, west, and south facades of the office building at Hakim Sabzevari University in terms of thermal efficiency using parametric analysis. For one year, three rooms on three floors of this building with window louvers at different depths, angles, and distances were thermally simulated with EnergyPlus software and the HoneyBee plugin in addition to the Galapagos plugin for optimization. Based on the optimized samples, it is possible to reduce the thermal energy consumption by 32.34%, 23.71%, and 30.2%, respectively using the ideal louvers on the east, south, and west facades. In terms of thermal efficiency, the distance between the blinds on the south facade and the angle between them on the east and west facades of a window louver are the most significant factors.

Groundwater plays a very important and fundamental part in human existence because of its essential role in living systems. The study aimed at carrying out an empirical study into groundwater protective potential and water quality around Obafemi Awolowo University solid waste facility and AbaGboro Community. This was achieved by using the electrical resistivity method to delineate the subsurface inhomogeneity around the dumpsite facility and also using the PG990 Atomic Absorption Spectrometer for metal analysis of water quality. The Schlumberger electrode array arrangement was engaged in the survey. A total of twelve vertical electrical soundings (VES) data was collected within the Obafemi Awolowo University dumpsite. The water samples were collected at two locations within the AbaGboro community which was 4.5 Km from the dumpsite to determine its quality. The results of the VES revealed the depth, resistivity, and thickness. The observed resistivity and the thickness values were further used in determining the groundwater protective potential, by calculating the Dar-Zarrouk parameters which showed that 91.7% of the study area is within poor/weak protective potential. The result from the water analysis of the hand-dug bore holes of the two different locations in the AbaGboro Community showed the presence of heavy metal concentrations as Pb, As, Mn, Cd, Zn, Cr and Co. Therefore, periodic assessment of water quality should always be carried out because we cannot anticipate when the groundwater will be contaminated due to relatively poor/weak groundwater protective potential.

In the present research, effects of nanoparticles and changing of tube diameter have been scrutinized on heat transfer parameters in the shell and helically coiled tube heat exchanger. A CFD analysis and also a modeling of the mentioned heat exchager have carried out by writing a code in MATLAB software for two regimes involving forced convection heat trasnfer in single phase fluid flow and sub-cooled boiling. In the case under analysis, considered nanoparticles in this research was Nickel nanoparticles with 0.1 and 1% volumetric concentration. Based on the results, both going up of volume concentration of nanoparticles and increasing of tube diameter are cause to make better heat transfer parameters. In truth, heat transfer coefficient and Nusselt number have been enhanced by 0.1 and 1 % volumetric concentration of Nickel nanoparticles.