Types Of Heat Transfer Fluids Research Articles

Irreversibility analysis of Darcy-Forchheimer flow of a Williamson hybrid nanofluids near a stagnation-point across a vertical plate with buoyancy force

PurposeA novel type of heat transfer fluid known as hybrid nanofluids is used to improve the efficiency of heat exchangers. It is observed from literature evidence that hybrid nanofluids outperform single nanofluids in terms of thermal performance. This study aims to address the stagnation point flow induced by Williamson hybrid nanofluids across a vertical plate. This fluid is drenched under the influence of mixed convection in a Darcy–Forchheimer porous medium with heat source/sink and entropy generation.Design/methodology/approachBy applying the proper similarity transformation, the partial differential equations that represent the leading model of the flow problem are reduced to ordinary differential equations. For the boundary value problem of the fourth-order code (bvp4c), a built-in MATLAB finite difference code is used to tackle the flow problem and carry out the dual numerical solutions.FindingsThe shear stress decreases, but the rate of heat transfer increases because of their greater influence on the permeability parameter and Weissenberg number for both solutions. The ability of hybrid nanofluids to strengthen heat transfer with the incorporation of a porous medium is demonstrated in this study.Practical implicationsThe findings may be highly beneficial in raising the energy efficiency of thermal systems.Originality/valueThe originality of the research lies in the investigation of the Darcy–Forchheimer stagnation point flow of a Williamson hybrid nanofluid across a vertical plate, considering buoyancy forces, which introduces another layer of complexity to the flow problem. This aspect has not been extensively studied before. The results are verified and offer a very favorable balance with the acknowledged papers.

CFD modeling of a triple‐walled direct absorption evacuated tube solar collector based on hybrid nanofluid/microencapsulated PCM

AbstractNowadays, direct absorption solar collectors are a new concept of solar collectors which have attracted special attention. The type of heat transfer fluid (HTF) has a significant influence on the efficiency of this kind of collector. Therefore, in this study, a wide range of working fluids including mono nanofluid ( and CuO), binary nanofluid, and especially the incorporation of a new hybrid combination of nanofluid and microencapsulated phase change material (MPCM), are used as the working fluids of a triple‐walled direct absorption evacuated tube solar collector. The computational fluid dynamics (CFD) method is used for simulating the collector and investigating the effect of different parameters including volume fraction, base fluid, mass flow rate, and type of absorber tube structure (double‐ and triple‐walled) on collector thermal performance. Results show that binary nanofluids of 0.06% /0.002% CuO/water and 0.06% /0.002% CuO/ethylene glycol (EG) have the largest working fluid temperature differentials equal to 48.31 and 66.5 K, respectively. It was inferred that, at the mass flow rate of 2.7 , the efficiency is obtained to be 60.29% employing binary/EG nanofluid, which is 8.68% and 15.31% higher than CuO/EG and /EG nanofluids, respectively. Inserting the hybrid CuO nanofluid/MPCM leads to an improvement of 1.14% and 1.22% in the efficiency of triple‐ and double‐walled collectors, respectively, with respect to the individual usage of the nanofluid. The thermal efficiency of the double‐walled structure is higher than triple‐walled considering all HTFs.

A review on nanofluid stability: preparation and application

Due to excellent thermal performance and application prospects, nanofluids are attracting many researchers to pay more attention to new types of heat transfer fluids. However, previous studies have focused on the effects of nanofluids on thermophysical properties without considering the limitation of dispersion stability in practical applications. Excellent nanofluid stability is judged with the zeta potential value above 30 mV. Unstable nanofluids block the fluid flow in heat exchanger channels, which reduces the system performance by over 23 %. Based on a systematic review of improving nanofluid stability, this research discusses the preparation, characterisation, influencing factor, dispersion mechanism, and dispersion method on nanofluid stability. Four methods for improving nanofluid stability are summarised. The nanofluid is stable at pH values between 4 and 9 b y controlling its ionic concentration. The nanofluid concentration is required below 2 % to improve the repulsion between nanoparticles. The stability of the nanofluid is affected by the type and amount of the surfactant, which fails to improve the nanofluid stability at temperature above 60 °C. In addition, the molecular forces between the mixed nanofluids enhance the stability of the nanofluid. This review examines the variation patterns of nanofluid stability and the effect of stability on heat transfer. It is expected to identify some opportunities and demonstrate future challenges in both the in-lab research and the commercialisation of nanofluids.

Impact of the Thermophysical Properties of a Cuo-H<sub>2</sub>O-Based Nanofluid on the Performance of a Cylindrical Solar Concentrator

Sustainability in energy production, energy security, and global warming are major concerns facing the globe today. Cylindrical Solar Concentrator is extensively utilized for technologically advanced processes, heat, and power plant applications by utilizing daylight sunshine at no running cost. Numerous inputs and characteristics impact the concentrator's performance, with the type of heat transfer fluid and its mass flow rate being two of the most important. This paper gives a numerical investigation of the influence of thermo-physical attribute of CuO water-based nanofluids on the effectiveness of the Parabolic Trough Solar Concentrator in Ogbomosho weather condition (lat. 8o011, long. 4o111).The governing equations of nanofluids with laminar flow and steady state, using iterative relaxation techniques, as well as the efficiency of the concentrator, were solved. A C++ simulation program was developed to investigate the impacts of thermo physical parameters on concentrator efficiency, with nanoparticle sizes ranging from 1 to 10 percent and mass flow rates of 0.1 kg/s, 0.15 kg/s, and 0.2 kg/s, at a constant incident solar insolation flux of 186 W/m2. The results demonstrated that increasing the mass flow rate of the nanofluids improves the heat transmission properties. The thermo physical properties of CuO-based nanofluids and its effects on the performance of the solar parabolic trough collector are being examined. The impact of thermophysical attributes on thermal effectiveness results in improved thermal efficacy, heat transfer characteristics of nanofluids, and factors influencing its features in solar collectors, which determines its usability. The Parabolic Trough Collector system based on nanofluids is a promising technology with applications in green surroundings.

Performance Investigation of Cylindrical Cavity Receiver Using Roughened Surfaces

Solar cavity receiver is an integral part of the solar parabolic dish collectors used for absorbing concentrated solar irradiation. The performance of the receivers can be enhanced utilizing different types of heat transfer fluids (HTF) and modified geometries. The thermal performance of a redesigned cavity receiver with solid semi-circular tube attached to its surface was investigated using CFD three-dimensional simulation. The influence of operating and geometric parameters (i.e., inlet mass flow rate and inlet temperature) were investigated. The results obtained shows that, redesigned solar cavity receiver has thermal efficiency of 8.49-10.27% higher than a normal cavity receiver with an inlet flow rate of 0.01-0.04 kg/s under the same environmental and operating conditions. The temperature of outlet of HTF increases with increases in inlet temperature for Therminol66 oil. The comparison of thermal performance using different HTF (i.e., Therminol66, Ethylene Glycol, Water) is also conducted and it is found that Therminol66 oil gives 9% and 17% higher outlet temperature than ethylene glycol and water respectively at intake flow rate of 0.02 kg/s.

Comparison of Thermal Behavior of Self-Designed Internally Cooled Cutting Tool for Various Heat Transfer Fluids-Statistic and Computational Fluid Dynamics Approach

Abstract Compared with dry machining, using traditional cutting fluids has some weaknesses, such as environmental pollution, high machining costs, and harmful effects on human health. Internally cooled cutting tools (ICCTs) have been promising, sustainable, health-friendly, and green technologies for turning applications. However, the effects of different types of internal coolant fluids on insert tip temperature (Ttip) have not been investigated for ICCTs. The machining quality of metallic materials and tool life can improve with effective cooling. This study investigates the internal cooling performance of a self-designed internally cooled smart cutting tool (ICSCT) by comparing different heat transfer fluids. Therefore, a conjugate heat transfer (CHT) model was set for a self-designed ICSCT. The CHT simulation was experimentally confirmed using pure water (…developed by Ozturk, E., Yildizli, K., and Saglam, F., 2021, “Investigation on an Innovative Internally Cooled Smart Cutting Tool With the Built-In Cooling-Control System,” Arab. J. Sci. Eng., 46(3), pp. 2397–2411). After that, the effects of flow velocity (Vf) and the inlet temperature of the coolant fluid (Tinlet) alongside different types of glycol-based heat transfer fluids (including pure water) on Ttip were statistically evaluated by the Taguchi method and analysis of the variance (ANOVA). It was found that the most influential factor was the Tinlet at a contribution ratio level of 88.32%. Additionally, according to statistics, Vf and the type of heat transfer fluid were significant. Hence, since no external coolant is used, the designed smart tool can be considered environmentally friendly and health-friendly. In conclusion, glycol-based fluids can be a better choice for internally cooled tool designs owing to their superior features, e.g., corrosion prevention, nontoxicity, and stable heat transfer capability at lower temperatures compared to pure water, although pure water has better thermal properties than the glycol-based fluids (Dynalene Heat Transfer Fluids Technical Datasheets, Cited March 31, 2020).

Selection of working fluids for solar organic Rankine cycle—A review

The performance of renewable energy systems can be significantly improved if power is produced from low-temperature heat sources. The organic Rankine cycle (ORC) is suitable for producing power from low-temperature heat sources. ORC finds applications alongside solar power, geothermal power, waste heat and biomass. ORC-enabled systems can contribute significantly to raising the effectiveness of renewable power sources. Solar power, for example, can deliver affordable electricity to remote locations and small industries. By employing ORC, power generation is possible at lower temperatures on cloudy days. Its main difference from the steam Rankine cycle is its working fluid. The ORC makes use of an organic, high molecular mass fluid as the working fluid. Compared to steam Rankine cycles, ORC works at a lower temperature (<250°C) and pressure. The only working fluid in the steam Rankine cycle is water, but the ORC can operate on hundreds of different working fluids. The design and performance of ORC systems are entirely dependent upon the suitable working fluid and, hence identification of the working fluid for ORCs is of utmost importance for diverse applications. Properties of working fluid have a considerable impact on the efficiency of the system. The main objective of this study is to identify the most suitable organic fluids having characteristics necessary for use in solar ORCs. In addition, a detailed review of the various types of heat transfer fluids now available in the market that are often used in ORC systems was conducted. This research assists in selecting the most appropriate organic fluids for various solar ORC applications in terms of operating circumstances.

Closed flow solar dehydration with the use of silver nanoparticles: Application for the production of Pouteria lucuma flour

In this research, a closed-flow solar dehydrator with a refrigeration moisture extraction system was evaluated, likewise, the dehydration temperature time was optimized by evaluating three types of heat transfer fluids. The dehydration equipment included devices to absorb thermal energy from incident sunlight, such as a trombe wall and a parabolic cylindrical collector, and a thermo bank system. In addition, the influence of three types of heat transfer fluids (water, oil and oil nanofluid + silver nanoparticles) was evaluated. This dehydration system was applied to process the Pouteria lucuma fruit. The results indicate the reduction of the dehydration time by 58.19% using nanofluid. This treatment prevents the modification of the physicochemical properties of the product and helps preserving its organoleptic properties.

Simulation of Minichannel Liquid Based Thermoelectric Cooling System by Changing Dimension of Minichannel and Type of Heat Transfer Fluid

Abstract: In recent time, due to exponential growth in electronic devices there is significant increase in heat dissipating element like integrated circuits(IC), graphical 2Assistant Professor, processing units (GPU) and central processing units (CPU). If there is no proper arrangement for heat removal it can permanently damage whole system. There are several methods used for this, one of which is thermoelectric cooling which works on peltier effect, thermoelectric devices with proper cooling arrangement act like heat pump which removes heat from one side and provide it to another side. The drawback of this system is low efficiency. In this project CFD analysis is done for minichannels of different dimensions along with thermoelectric. Simulation is performed by changing parameters such as hydraulic diameter of minichannel, changing type of heat transfer fluid and mass flow rate of fluid. The study reveals that by optimizing these parameters performance of thermoelectric system can be improved. The aim of this study is to optimize these parameters in order to improve overall heat transfer coefficient and coefficient of performance of the system. Keywords: Thermoelectric cooling, Peltier effect, Minichannel, Overall heat transfer, CFD

Toward a highly efficient photovoltaic thermal module: Energy and exergy analysis

To obtain maximum exergy and energy efficiencies of photovoltaic-thermal (PV-T) systems, innovative configurations of coolant tubes are proposed and simulated numerically. The tubes’ configuration is modified using non-uniform wavy tube concept, which forms different styles, including ascending and descending amplitude of coolant tubes. Besides, the influences of geometrical parameters, extending PV panel length, sensitivity analysis on the operating conditions and a comprehensive investigation of different types of heat transfer fluids are analysed for the innovative systems. The results demonstrate that the PV-T performance develops in terms of electrical, thermal, and exergy efficiencies using ascending wavy tubes compared with straight, uniform wavy and descending wavy tubes. The electrical and thermal efficiencies are promoted from 10.94% to 61.04% for the straight tubes to 11.32% and 65.21%, respectively, for the system in which ascending wavy tubes are utilised. A comprehensive study of different coolant fluids proves that when SiC and MPCM-28 are simultaneously employed, the best cooling fluid is achieved, leading to a 0.4% higher electrical efficiency than the case in which water is used.

Comprehensive mathematical model and efficient numerical analysis of the design parameters of the parabolic trough receiver

A new efficient computational approach for the determination of the main design parameters of the parabolic trough receiver is presented. The approach is based on a classical combination of the Monte Carlo ray tracing method for the optical problem and the 3D finite volume method for the thermo-fluid problem. Unlike previous studies, modeling was carried out using a created fully dimensionless thermo-fluid mathematical model and dimensionless numerical algorithm. Criterial complexes (relations between thermophysical, dynamic and geometrical properties) act as dimensionless variables in a mathematical model. A single criterial dependency for describing the temperature fields for any receiver geometry and any heat transfer fluid type was obtained. A proposed solution is correct for any inlet and ambient temperatures. The impact of concentrator surface errors and the design of a tube receiver on temperature fields was studied as well. The present study is the first attempt to mathematically generalize the thermo-fluid analysis in the parabolic trough receiver. A user can efficiently evaluate and predict all thermo-fluid parameters for chosen parabolic trough concentrator geometry with only one dependency without using costly standard software packages. Obtained data is useful for analysis during both the design and operational stages.

Preparation and Characterization of Rutile Titania Nanofluids Stabilized in Different Surfactants Base Fluids

Background: Improvement of conventional heat transfer fluids for achieving higher energy efficiencies in thermal equipment is a key parameter to conserve energy in industries. The heat transfer fluids such as water, oil and ethylene glycol greatly suffer low heat transfer performance in industrial processes. There is a need to develop new types of heat transfer fluids that are more effective in terms of heat transfer performance. Nanofluids enhance thermal conductivity and improve the thermal performance of heat transfer systems. Methods: New titania nanofluid samples consisting of 0.0625 to 1% TiO2 nanoparticles were prepared and characterized. The method of preparation was based on prior precipitation of TiO2 from an ammoniacal solution of pH 9 and calcination at 900°C. Solubilization, homogenization and stabilization of the of the nanoparticles were performed by sonication in the presence of sodium dodecyl sulfate (SDS) anionic surfactant and cetyltrimethylammonium bromide (CTAB) cationic surfactant. Results: This treatment was also utilized to increase the stability and improve the thermal properties of the fluid. Conclusion: Several characterization techniques including measurements of hydrodynamic size distribution, zeta potential, transmission electron microscopy (TEM), viscosity, density, specific heat, thermal conductivity, and sedimentation photo capturing were used to measure and confirm the stability and sedimentation rate of the prepared nanofluids.

Performance assessment of a solar powered hydrogen production system and its ANFIS model

Apart from many limitations, the usage of hydrogen in different day-to-day applications have been increasing drastically in recent years. However, numerous techniques available to produce hydrogen, electrolysis of water is one of the simplest and cost-effective hydrogen production techniques. In this method, water is split into hydrogen and oxygen by using external electric current. In this research, a novel hydrogen production system incorporated with Photovoltaic – Thermal (PVT) solar collector is developed. The influence of different parameters like solar collector tilt angle, thermal collector design and type of heat transfer fluid on the performance of PVT system and hydrogen production system are also discussed. Finally, thermal efficiency, electrical efficiency, and hydrogen production rate have been predicted by using the Adaptive Neuro-Fuzzy Inference System (ANFIS) technique. Based on this study results, it can be inferred that the solar collector tilt angle plays a significant role to improve the performance of the electrical and thermal performance of PVT solar system and Hydrogen yield rate. On the other side, the spiral-shaped thermal collector with water exhibited better end result than the other hydrogen production systems. The predicted results ANFIS techniques represent an excellent agreement with the experimental results. In consequence, it is suggested that the developed ANFIS model can be adopted for further studies to predict the performance of the hydrogen production system.

Experimental investigation and cost analysis on a nanofluid-based desalination system integrated with an automatic dual-axis sun tracker and Fresnel lens

In this experimental work, the performance of a nanofluid-based solar still equipped with a dual-axis solar tracker system (STS) has been investigated through various viewpoints, i.e., daily and nightly fresh-water production, hourly and daily efficiency and cost. The proposed solar still consists of a conventional solar still (CSS), three Fresnel lens concentrator, and an active automatic STS. Moreover, the effects of deionized water, MWCNTs/water nanofluid with two mass fractions of 0.15 and 0.3%, as the heat transfer fluid (HTF), are studied on fresh-water productivity to evaluate the appropriate HTF type. The daily, nightly, and total fresh-water produced by the CSS with internal condenser is found to be 2180, 560, and 2740 mL/(m2·day), respectively. However, the CSS integrated with STS and Fresnel lens can produce daily, nightly, and total fresh-water of 5310, 1080, and 6390 mL/(m2·day), respectively. In addition, the results indicate that using MWCNTs/water nanofluid with a mass fraction of 0.3% enhances fresh-water productivity by 31.6, 7.4, and 27.5%, respectively, compared to that of pure water as HTF. The results reveal that by using the nanofluid with a mass fraction of 0.15 and 0.3%, the daily average efficiency is increased about 9.56 and 17.85%, respectively, compared to that of pure water as HTF.

Synthesis and characterization of nanofluids from the biosynthesis of nanoparticles and their evaluation in solar thermal systems

The objective of the study was to evaluate diverse and known types of heat transfer fluids (water, oil and glycerin) commonly used in solar thermal systems, in this work denoted as base fluids, with respect to them, but with the addition of biosynthesized metal nanoparticles. It was considered a prototype of solar heating systems by thermosiphon in the application-experimental phase assisted by halogen light (with wavelengths ranging from deep infrared to violet). The process of biosynthesis or green synthesis of silver nanoparticles (NP Ag) was from the precursor of silver nitrate (AgNO3) and using as a reducer the alcoholic extract from agroindustrial residues of the wine production, obtaining colloids with high monodispersity and with sizes between 30 and 40 nm. (spherical geometry). The results suggest a greater increase in heat absorption capacity when biosynthesized silver nanoparticles are added to the oil, which managed to have a heat capacity of 3519.41 J/kg°C.

Sensible and latent heat energy storage systems for concentrated solar power plants, exergy efficiency comparison

Different options of sensible and latent heat storage systems comprising different types of heat transfer fluids, heat storage media or phase change materials (PCMs) have been compared considering the upstream and downstream requirements of a concentrated solar power cycle. For an optimal system, analysis of both the energy efficiency and exergy recovery of the storage system and the whole cycle of heat to power is necessary. This study provides this analysis, comparing a two-tank sensible storage system to latent heat shell and tube storage system, using an analytical method, ε-NTU. For the case of molten salt as the PCM and sCO2 as the heat transfer fluid, results show 4.02% higher exergy recovery for the two-tank system at a working temperature range 450–700 °C compared to 450–660 °C for the latent heat storage system where the upper limit is the PCM melting temperature. Compared to the Carnot cycle efficiency (the highest rate of useful energy (exergy) recovery for an isentropic process) of 70%, the overall efficiency of the two-tank system, the base case of molten salt/sCO2, molten salt/Na, and molten metal/sCO2 are 57.41%, 53.39%, 55.21%, and 53.55%, respectively. The gap in efficiency between the sensible and latent heat storage systems decreases by lowering the thermal resistance of heat transfer fluid side and/or the PCM side. Specifically, the gap in efficiency decreases 45% by using liquid Na instead of sCO2 and a 4% decrease is observed when replacing molten salt with a molten metal like aluminium as the PCM. Using PCMs with higher melting temperature is preferred with liquids with high thermal conductivity like Sodium. For a heat transfer fluid such as sCO2 with low thermal conductivity, a higher inlet fluid temperature and/or a low temperature PCM can provide high exergy efficiency. For a specific combination of PCM and heat transfer fluid, an optimal melting temperature exists depending on the inlet temperatures during charging/discharging and the thermophysical properties of the media. The study shows that PCM storage provides opportunities to minimise causes of irreversibilities to achieve simultaneous high volumetric energy density and high exergy recovery for CSP application in comparison with the conventional two-tank sensible storage.

Influence of vapor phase soldering fluid Galden on wetting forces (tombstone effect)

Vapour phase soldering brings besides many advantages for reliability in electronic production an increased incidence of tombstoning errors. The imbalance of wetting forces has a decisive effect on the tombstoning phenomena, and the changes in wetting forces during the vapour phase soldering are therefore analyzed and evaluated. Two types of solders (leaded Sn63Pb and lead-free SAC387 alloy) and two types of heat transfer fluids (Galden LS 230 and Galden HS 240) were used. The use of soldering fluids changes the surface tension equilibrium vectors for both used solders and changes the measured wetting force by up to 20%. The measurement was performed by wetting balance method using non-wetting sample.

Experimental study using different heat transfer fluid of a packed bed thermal energy storage system during charging process

Heat transfer analysis of a packed bed-PCM latent heat thermal energy storage system is presented in this article. The cylindrical packed bed is filled with spherical capsules of PCM (water) that is used for an air conditioning commercial application. In the study, the experimental model is tested to analyse the thermal performance of packed bed-PCM latent. The results obtained are used for the thermal behaviour of charging process. The main objective is to compare the loading time using as heat transfer fluid (HTF) ethylene glycol and ethanol. The effects of mass flow rate, freeze rate and inlet HTF temperature are investigated. The results of the study indicate that changing the HTF type and inlet temperature have different effects on total time in charging process.

Heat transfer fluids for concentrating solar power systems – A review

• This study deals with liquid metals, molten salts and other heat transfer fluids. • Molten salts show advantages in operating conditions up to 800 °C. • Temperature range, viscosity, thermal conductivity and corrosion etc. are discussed. There is a strong motivation to explore the possibility of harnessing solar thermal energy around the world, especially in locations with temperate weather. This review discusses the current status of heat transfer fluid, which is one of the critical components for storing and transferring thermal energy in concentrating solar power systems. Various types of heat transfer fluids including air, water/steam, thermal oils, organic fluids, molten-salts and liquid metals are reviewed in detail, particularly regarding the melting temperature, thermal stability limit and corrosion issues. Stainless steels and nickel based alloys are the typical piping and container materials for heat transfer fluids. Stability of the stainless steels and alloys while in contact with heat transfer fluids is very important for the longevity of concentrating solar power systems. Corrosion properties of stainless steels and nickel based alloys in different heat transfer fluids are discussed in terms of corrosion rates.

Measuring the thermal conductivity of heat transfer fluids via the modified transient plane source (MTPS)

Heat transfer fluids are often a critical performance component in industrial processes and system design. Fluids are used in heat dissipation to maintain stable operating temperatures in a variety of applications, such as diesel engines, chemical production, asphalt storage, and high-power electric transformers. A wide range of fluids specific to various applications are available, thus a reliable and accurate thermal conductivity characterization is extremely important. Thermal conductivity analysis of heat transfer fluids with traditional methods is time-consuming and error-prone due to the impact of convection. Convection often distorts effective thermal conductivity measurement as an additional source of heat transfer. The modified transient plane source method implemented in the C-Therm Technologies TCi Analyzer provides an easy way to accurately measure the thermal conductivity and distinguish this form of heat transfer in negating the impact of convection by (a) employing the shortest test time in commercially available sensors (0.8 s), (b) offering a minimal sample volume requirement (1.25 mL), and (c) employing a low-energy power flux to the specimen under test (approximately 2,600 W m−2). This work presents thermal conductivity results generated on three types of heat transfer fluids over a wide temperature range and discusses the significance of the data in relevance to the application.