Omid Mahian

Xi'an Jiaotong University | XJTU · Chemical Engineering

Sustainable socio-economic development largely depends on the sustainability of the energy supply from economic, environmental, and public health perspectives. Fossil fuel combustion only meets the first element of this equation and is hence rendered unsustainable. Biofuels are advantageous from a public health perspective, but their environmental...

Biohydrogen is emerging as a promising carbon-neutral and sustainable energy carrier with high energy yield to replace conventional fossil fuels. However, biohydrogen commercial uptake is mainly hindered by the supply side. As a result, various operating parameters must be optimized to realize biohydrogen commercial uptake on a large-scale. Recentl...

This paper presents a new way to hyper-optimise a flat plate solar collector using a combination of regenerated point clouds, constructal theory, and physics-informed machine learning (PIML). The behaviour of the flat plate solar collector is studied as solar radiation and ambient temperature change, using both precise numerical simulation and PIML...

Flow boiling heat transfer in microchannels is fundamentally important for the thermal management of highpower electronics. The combination of silica nanofluids and micro pin-fins structure is expected to solve the limitations of the internal trade-off between the heat transfer coefficient (HTC) and critical heat flux (CHF). However, the high cost,...

Due to the increment of energy demand, the current requirement for optimum design of a trigeneration system has become more imperative than ever. The present work deals with the simulation of the demand energy and optimization of a trigeneration system for a hotel building in Mashhad using GAMS software where four objective functions including ener...

Lithium-ion battery (LIB) packs with high power density are necessary in battery-powered system development. In this study, we investigated LIB packs made of compact cylindrical Li-ion batteries. We arranged the batteries in various patterns, including square, lozenge, elliptical, and circular, with all patterns occupying the same total area. We so...

This study presented a novel liquid-cooled heat sink based on constructal theory. An experiment was conducted to investigate the influence of boundary conditions, such as the mass flow rate (ṁ), on heat transfer rate (Qin) and pressure drop. Five cylinder heater cartridges were used in the experiment for 11 different mass flow rates (0.008292 < ṁ (...

New renewable energy technologies in different designs and forms are emerging every day as a result of the global awareness about the necessity of green transition and strict milestones set for 2050. Among all of the emerging technologies in this area, solar direct electricity generating systems (i.e. photovoltaic [PV], and photovoltaic-thermal [PV...

In remote areas, providing electricity through grid-connected energy systems or transferring fossil fuels would be economically infeasible. A stand-alone hybrid renewable energy system is considered as an effective solution to supply electricity to remote areas' populations. In this study, the techno-economic feasibility of a solar-driven ORC/Photo...

The air-side performance of a novel alternating cross-section flattened (ACF) tube heat exchanger was experimentally investigated. Three heat exchangers with an in-line tube arrangement and two tube rows were used as the test sections. The tube configuration is the highlight of the research work. ACF tubes with hydraulic diameters of 4.16, 4.75, an...

Freshwater supply is declining in the context of climate change, pollution, and soil salinization, calling for sustainable methods to produce drinking water. For instance, salt water can be converted into pure water by steam generation. Interfacial solar steam generation involves photoabsorbers consisting of a photothermal material with broad solar...

Interfacial solar steam generation (SSG) has emerged as a promising solution to address the global challenges of water scarcity. Herein, for the first time, by pressing micro-scale sawdust into a polystyrene mold using a manual hydraulic press and enclosing it in an aluminum grid (S/Al), a substrate for SSG was made. Adjusting the porosity of the S...

Nearly half of the global energy consumption goes toward the heating and cooling of buildings and processes. This quantity could be considerably reduced through the addition of advanced thermal energy storage systems. One emerging pathway for thermal energy storage is through nano-engineered phase change materials, which have very high energy densi...

Desalination has gained significant importance in recent decades especially in arid regions such as MENA. There are different technologies for desalination such as thermal, electro-dialysis and Reverse Osmosis (RO); however, RO is currently among the most attractive and widely used technology. Utilizing renewable energy systems for supplying the re...

Self-powered sensing systems augmented with machine learning (ML) represent a path toward the large-scale deployment of the internet of things (IoT). With autonomous energy-harvesting techniques, intelligent systems can continuously generate data and process them to make informed decisions. The development of self-powered intelligent sensing system...

Serrated welded spiral fin-and-tube heat exchangers (SWSFTHXs) are experimentally investigated. The work primarily focuses on the effects of the segmented fin height (hs) with various fin pitches (fp) on the air-side performance (ASP). Experimental results show that SWSFTHXs provide a higher air-side heat-transfer coefficient than the plain welded...

Solar‐driven hydrogel evaporator used for water purification demonstrates great potential in seawater desalination and domestic sewage treatment. However, much uncertainty still exists about the most efficient design to obtain cost‐effective drinkable water. In this paper, a natural rich biomass Nicandra physalodes (Linn.) Gaertn. polysaccharide wa...

The photothermal properties of nanofluids have been the focus of direct absorption solar collectors (DASCs). At present, there are few studies on the application of nanofluids in high temperature field. Liquids with low specific heat capacity can reach higher temperatures under the same solar radiation, which broadens the application of nanofluids...

The simulation of flow patterns and the thermal behavior of pore-scale porous media (PSPM) require multilayer calculation when the simulation domain is large. In this study, multi-layer calculations based on the tensor-based data transfer protocol (TBDTP) were used to simulate the flow pattern and the thermal behavior of PSPM walls, including phase...

The growing volume of municipal solid waste (MSW) generated worldwide often undergoes open dumping, landfilling, or uncontrolled burning, releasing massive pollutants and pathogens into the soil, water, and air. On the other hand, MSW can be used as a valuable feedstock in biological and thermochemical conversion processes to produce bioenergy carr...

We studied the effect of fin patterns on the air-side performance of a novel type of heat exchanger, namely louver spiral fin-and-tube heat exchangers (LSFTHXs). We investigated three types of fin patterns—radial, curved, and mixed-louver spiral fins—and compared their characteristics with plain spiral fin. We fabricated heat exchangers with a crim...

Coughing and sneezing are the main ways of spreading coronavirus-2019 (SARS-CoV-2). Strategically critical facilities such as power plants cannot be shut down even in challenging situations like the COVID-19 outbreak. The personnel of the power plants' control room need to work together at close distances. This study presents the computational flui...

Although various types of radiative cooling have been investigated, providing more cooling efficiency is always a challenge. One of the most critical challenges of radiative coolers is the ability to cool during the daytime against direct sunlight. In this work, the efficiency of the radiative cooler is increased by proposing an innovative design c...

This forward-looking perspective article presents a status overview of solar photovoltaic-thermal (PVT) panels in net-zero energy buildings from various points of view and tries to picture the future of the technology in this framework. The article discusses the pros and cons of PVTs' state of practice, design developments, and integration possibil...

This paper aims to summarize publications related to new generation of tube geommetry, thermal performance, and flow characteristics in different cross-sectional manners, and the effect of crucial parameters on thermal–hydraulic performance. An alternating cross-sectional tube has an enhanced vorticity without installing vortex generator devices. M...

It is now well established that electrochemical systems can optimally perform only within a narrow range of temperature. Exposure to temperatures outside this range adversely affects the performance and lifetime of these systems. As a result, thermal management is an essential consideration during the design and operation of electrochemical equipme...

NOx and their derivatives have severe environmental and health impacts. Concerning the environment, nitrogen oxide has a higher global warming potential. It reacts with organic compounds to form photochemical smog. Furthermore, NOx is well known for the formation of atmospheric ozone and secondary aerosol, which contribute to particulate matter emi...

Recently, using nanofluids (NFs) for solar-powered production of drinking water has become of great importance and has drawn much attention for reducing the water storage crisis. The research results showed an increase in the NFs concentration improves the sunlight harvesting. Moreover, low stability of the NFs would negatively impact on the produc...

Total interpretive structural modeling Cross-impact matrix multiplication applied to classification A B S T R A C T The world is experiencing the third wave of electronic commerce, in which battery-free electronics dominate the market share. Additionally, the wide distribution of the sensors and high maintenance costs make batteries an insufficient...

A generic integrated configuration-size optimisation formulation for design of hybrid renewable energy systems (HRES) is presented in this paper. This formulation allows identifying the optimum configuration for a given site and the optimum size of each component in that configuration by solving only one optimisation problem. Single and multiobject...

This paper presents the air-side performance (ASP) of embedded and welded spiral fin and tube heat exchangers (SFTHXs). Six heat exchangers were tested to investigate the effect of fin-base connections and fin pitch. Test sections were fabricated from steel tubes, with two rows of tubing and a Z-shaped water flow arrangement, and an aluminum fin wi...

Despite massive efforts in the field of nanofluids over the last few decades, nanofluids are primarily still used in a lab scale due to numerous controllable and uncontrollable barriers that impede their effective large-scale implementation. Nanofluids market uptake can be realized only when those barriers have been overcome. These barriers must be...

Ionic liquids and their family known as deep eutectic solvents are non-flammable, nonvolatile, recyclable and environmentally friendly working fluids, making them suitable for use in various thermal systems. By adding nanoparticles to these fluids (through special physical and chemical approaches), one can augment their specifications (especially t...

The performance of crimped spiral fin-and-tube heat exchangers (CSFTHXs) with a small tube diameter at a Reynolds number of 1500-6400 based on the tube's outer diameter is experimentally investigated. An important factor in this study is the small-diameter tubing, with an outer diameter of 9.53 mm. Copper tubes and aluminum fins are assembled as CS...

The organic Rankine cycle (ORC) is an effective technology for power generation from temperatures of up to 400 • C and for capacities of up to 10 MW el. The use of solar irradiation for driving an ORC is a promising renewable energy-based technology due to the high compatibility between the operating temperatures of solar thermal collector technolo...

This study deals with the influence of hybrid nanofluids i.e., a mixture of Al2O3 and Multi-wall carbon nanotubes (MWCNTs) dispersed in water, on the environmental performance of a direct absorption parabolic trough collector. For this purpose, hybrid nanofluids in three volume concentrations i.e., 0.01%, 0.02%, and 0.04% were prepared and their op...

Biodiesel, the most suitable diesel fuel alternative, is currently gaining popularity due to its advantages and potential environmental protection. Besides, one of the environmental sustainability approaches in biodiesel production process would be the reuse of biomass waste. In this regard, this work focuses on sustainability and environmental fac...

Herein, a cost-effective, bifunctional, scalable, and highly efficient water-treatment material was prepared by coating iron/nickle (Fe/Ni)-reduced graphene oxide (RGO) nanocomposite on poplar wood which was used both as non-noble metal based photoabsorber in interfacial solar steam generation of seawater and as highly efficient heavy metal sorbent...

Building sector is responsible for approximately 40% of global carbon dioxide emission. Accordingly, any measures for reducing building energy consumption or providing it with renewable sources would substantially benefit sustainable development. A major approach towards this goal could be the application of photovoltaic modules in buildings, which...

Organic Rankine Cycle (ORC) is a promising electricity production technology that exploits low and medium heat sources. Usually, renewable and alternative heat sources can be used in order to feed an ORC with heat. The exploitation of geothermal energy is a usual and sustainable way to feed an ORC because it is a sustainable, abundant, economical a...

Background The rate of evaporation in direct solar steam generation can be increased by employing several techniques. One of the passive techniques that can be used for the improvement of system performance is the use of phase change materials (PCMs). Methods An experimental study was carried out to explore the role of PCMs in energy storage and c...

This experimental study investigated how changes in the water flow rate affected the number and size of microbubbles using venturi with equal entry and exit angles of 30°. The water flow rate ranged between 10 and 18 m3/h . Photos of microbubbles were taken with a digital camera in a visualized section that was specifically installed to store a cer...

In this study, the motion and distribution of droplets containing coronaviruses emitted by coughing of an infected person in front of a classroom (e.g., a teacher) were investigated using CFD. A 3D turbulence model was used to simulate the airflow in the classroom, and a Lagrangian particle trajectory analysis method was used to track the droplets....

Flow behavior and heat transfer characteristics of air flow inside the plate pin fin heat sinks (PPFHS) are presented. The effects of pin fin shape, pin fin orientation, and ratio of distance between pin and plate fin center to pin fin size (S/Dp or S/Wp) on the flow pattern and heat transfer coefficient (HTC), pressure drop (ΔP) and thermal perfor...

In the present work, artificial neural networks have been developed to predict the relationship and influence of shear rate/temperature and particle loading on the viscosity, density, thermal conductivity and isobaric specific heat capacity of Al2O3 nanoparticles dispersed in a binary mixture of water and ionic liquid ([C2mim][CH3SO3]/water). The p...

s The influence of the wavy-strip insert on photovoltaic-thermal (PVT) system performance was studied. To this end, computational fluid dynamics were used to model the 3-D PVT system and wavy-strip insert. The effect of the wavy-strip insert in a given total mass flow rate was examined on different numbers of the tube (N), which is in the range of...

Inorganic adhesives have received increased attention due to their high temperature resistance, non-toxicity, and environment friendliness. However, poor adhesion strength of inorganic adhesives hinders their application. Further, graphene improves the mechanical and thermal properties of polymer composites. Herein, graphene nanoplatelets (GNP) wit...

The enhancement of heat transfer between parallel surfaces, including parallel plates, parallel disks, and two concentric pipes, is vital because of their wide applications ranging from lubrication systems to water purification processes. Various techniques can be utilized to enhance heat transfer in such systems. Adding nanoparticles to the conven...

Biodiesel has the potential to significantly contribute to making transportation fuels more sustainable. Due to the complexity and nonlinearity of processes for biodiesel production and use, fast and accurate modeling tools are required for their design, optimization, monitoring, and control. Data-driven machine learning (ML) techniques have demons...

It has been more than two decades since the discovery of ‘nanofluids’ – mixtures of common liquids and solid nanoparticles with at least one dimension below 100 nm in size. While colloidal suspensions of particles (which include larger particles) have been studied for several decades, the term ‘nanofluids’ designates fluid systems that have enhance...

Energy system optimization is a significant task aimed at optimizing system operations and reducing costs and emissions. In this paper, an energy system is presented for multi-energy generation of power, heating/cooling, and desalination. First, the cycle’s exergy, exergoeconomics, and environmental impact are analyzed. Then, optimization is perfor...

An investigation was experimentally performed to explore the influence of geometrical parameters on the evaporative heat transfer coefficient and pressure drop of R-134a in dimpled tubes. The test sections were the counter-flow tube-in-tube heat exchanger, where the refrigerant was evaporated in the inner tube and hot water flows in the annulus. Se...

The present article deals with the computational fluid dynamics (CFD) investigation of flow and heat transfer of a [C2mim][CH3SO3]/Al2O3 ionanofluid in one conventional tube and two different grooved tubes. The flow is considered to be single-phase and laminar (500 < Re < 2000), and the range of nanoparticle concentration is between 0.05 and 2 %. F...

Nanogenerators have attracted particular attention during the last decade. A nanogenerator harness mechanical or thermal energy to produce electricity without any need for battery. In this paper, general descriptions of different types of nanogenerators, including piezoelectric, triboelectric, and pyroelectric, are presented. Next, bibliometric ana...

In the last decades, many drastic efforts have been undertaken to attain solar selective absorber coatings with high thermal stability and performance for better solar energy capture. Nanomaterials that are attached at the back-side, front-side, or inside of laminated absorber coatings play a determinative novel role, thus improving the thermal per...

Versatile bio-derived catalysts have been under dynamic investigation as potential substitutes to conventional chemical catalysts for sustainable biodiesel production. This is because of their unique, low-cost benefits and production processes that are environmentally and economically acceptable. This critical review aspires to present a viable app...

A small plate heat exchanger filled with copper foam which can be applied for small scale electronic cooling is presented. The heat transfer coefficient and pressure drop of water flow inside a plate heat exchanger filled with copper foam (PHECF) are experimentally studied. The effect of copper foam pore density and water velocity on the optimum th...

Numerous researches to prepare and stabilize graphene-based nanofluids have been developed.

The increasing demand for energy around the world makes it vital to use more suitable and efficient power generation systems. Combined heat and power (CHP) systems can produce power and heating with high possible efficiency. Also, in recent years, there has been a particular emphasis on exergy analysis for enhancing the efficiency of CHPs. In this...

Using renewable energy, especially solar energy, is an essential requisite for preventing global warming and climate change. Solar-powered steam generation is one of the recent solutions to the problem of environmental pollution and can be a promising way to generate clean energy. In this study, the superficial and volumetric approaches of the zinc...

New experimental data were presented on the effect of heat exchanger plate surface roughness, mass flux, average quality, heat flux, and temperature on the evaporative heat transfer coefficient (HTC) and frictional pressure gradient (FPG) of R-134 flowing in a plate heat exchanger (PHE). Three different plate surface roughness of 0.594 μm, 1.816 μm...

The air side thermal performance of wavy fins with rectangular winglets are studied using experimental and numerical methods. The following parameters are selected for investigation: the attack angle, placed location, span and length of the rectangular winglet. The results show that all parameters affect the thermal performance of the air side. The...

Due to their superior thermophysical properties, there is a growing body of work on nanofluids in the field of thermal systems. However, there is no specific review of the role of the nanoparticle shape, which has been found crucial to their performance adjustment. A comprehensive literature review of the effect of nanoparticle shape on the hydroth...

This study was set up to model and optimize the performance and emission characteristics of a diesel engine fueled with carbon nanoparticle-dosed water/‎diesel emulsion fuel using a combination of soft computing techniques. Adaptive neuro-fuzzy inference system tuned by particle ‎swarm algorithm was used for modeling the performance and emission pa...