Showing papers on "Heat exchanger published in 2019"
TL;DR: In this article, the impact of using fins and nano-sized materials on performance of discharging system was investigated, and the mathematical model has been offered in the form of PDE's, which were solved using Galerkin FEM.
336 citations
TL;DR: In this paper, a review on application of nanofluids in heat exchangers has been addressed, and it can be concluded that the use of nanophotonics in most cases improves heat transfer, which reduces the volume of heat exchanger, saving energy, consequently water consumption and industrial waste.
325 citations
TL;DR: In this article, the authors focused on various flow and heat transfer modes of nanofluid, metal foam and the combination of the two, with the physical properties of nanophluid and metal foam summarized.
252 citations
TL;DR: In this paper, a triplex-tube heat exchanger (TTHX) with phase change materials (PCMs) has been found to be a very efficient energy storage application for this purpose, but the low thermal conductivity of PCMs makes them unable to give the desired response for storage and recovery.
177 citations
TL;DR: Wang et al. as mentioned in this paper analyzed the current technologies for low-temperature waste heat recovery from two aspects: (i) the local waste heat extraction technology and (ii) global optimization of energy flow network.
161 citations
TL;DR: In this article, thermal conductivity of thermmosyphons has been investigated for different heat transfer purposes including cooling devices and heat exchangers, and thermal performance of thermal performan...
Abstract: Thermosyphons have high effective thermal conductivity and are applicable for different heat transfer purposes including cooling devices and heat exchangers. In the present study, thermal performan...
152 citations
TL;DR: In this article, a review of the other works carried out in the enhancement of optical and thermal efficiency of the solar PTC is presented along with the economic analysis of the PTC followed by the future research prospects in a parabolic trough collector and economic assessment models.
142 citations
TL;DR: Results indicate that LSSVM approach has the best performance and the proposed model by this approach has R-squared value equals to 1.
134 citations
TL;DR: In this paper, the authors present a preliminary introduction of organic Rankine cycle waste heat recovery (ORC-WHR) in heavy-duty diesel (HDD) vehicle applications in the past decade.
Abstract: Effective recovery of heavy-duty vehicle waste heat is a key solution toward meeting the increasingly stringent fuel economy and CO2 emission standards. Different from previous publications, this paper presents a preliminary introduction of organic Rankine cycle waste heat recovery (ORC-WHR) in heavy-duty diesel (HDD) vehicle applications in the past decade. It presents a wide range of topics in the HDD vehicle ORC-WHR system development, including system architecture evaluation, heat exchanger selection, expander selection, working fluid selection, power optimization, control strategy evaluation, simulation and experimental work overview, and limiting factors. In the system architecture selection, the tradeoff between fuel savings and system complexity dominates. In the heat exchanger design, besides the heat exchanger efficiency, transient evaporator response is critical factor for the system control and performance. The expander type and configuration is closely coupled to the expander power output type (i.e. electricity or mechanical power). WHR power production is most sensitive to working fluid mass flow rate, with less sensitivities to expander speed and condenser coolant mass flow rate. The integration of ORC-WHR control with engine control shows potential to improve the waste heat recovery system performance. The simulation studies predict higher power recovery levels than that in experimental work (0–60 kW vs. 0–14 kW), which could result from the large number of heat resources, optimistic expander and pump efficiencies and neglected heat losses in the simulations.
128 citations
TL;DR: In this paper, the authors present the results of an experimental investigation on the heat transfer characteristics of multi-walled carbon nanotube aqueous nanofluids inside a countercurrent double-pipe heat exchanger using porous media.
Abstract: This paper presents the results of an experimental investigation on the heat transfer characteristics of multi-walled carbon nanotube aqueous nanofluids inside a countercurrent double-pipe heat exchanger using porous media. Aluminum porous media (e = 67%) were used because of the construction of the medium, with porous plate media at the center of the inner tube and with three porous plates on the walls of the inner tube. The effects of operating parameters including flow rate (4600 < Re < 7600), mass fractions of nanofluids (0.04–0.25 mass%), and inlet temperature of nanofluids (Tin = 50 °C) on the heat transfer coefficient were investigated. The results indicate that imposing the plate porous media increases the heat transfer coefficient significantly, and the highest increase in the heat transfer coefficient is 35% which is obtained in the test of the lowest mass fraction (0.04 mass%) with three-plate porous media in the experiment range. As the mass fractions increased, the value of heat transfer enhancement assisted by porous media gradually decreased. Also the lower range 100 (L h−1) of the volume flow rate has a powerful enhancement on the enhancement coefficient, while the higher ranges 300 (L h−1) have low influence.
124 citations
TL;DR: In this article, the authors reviewed recent developments and utilisation of different types of porous materials in the heat exchangers and discussed the gaps in current literatures and designs and solutions for them.
TL;DR: In this paper, an experimental and numerical feasibility study of an integrated solar membrane distillation prototype was conducted for both potable water and/or thermal energy production on rooftops of residential and commercial buildings.
TL;DR: In this article, the authors compared the performance of a non-Newtonian hybrid nanofluid with temperature-dependent thermal conductivity and viscosity compared with a Newtonian hybrid nano-fluid with constant thermophysical properties.
Abstract: The objective of this study is to assess the hydrothermal performance of a non-Newtonian hybrid nanofluid with temperature-dependent thermal conductivity and viscosity compared with a Newtonian hybrid nanofluid with constant thermophysical properties. A counter-current double-pipe mini-channel heat exchanger is studied to analyze the effects of the hybrid nanofluid. The nanofluid is employed as the coolant in the tube side, while the hot water flows in the annulus side. Two different nanoparticles including tetramethylammonium hydroxide-coated Fe3O4 (magnetite) nanoparticles and gum arabic-coated carbon nanotubes are used to prepare the water-based hybrid nanofluid. The results demonstrated that the non-Newtonian hybrid nanofluid always has a higher heat transfer rate, overall heat transfer coefficient, and effectiveness than those of the Newtonian hybrid nanofluid, while the opposite is true for the pressure drop, pumping power, and performance evaluation criterion. Supposing that the Fe3O4-carbon nanotube/water hybrid nanofluid is a Newtonian fluid with constant thermal conductivity and viscosity, there leads to large error in the computation of pressure drop (1.5–9.71%), pumping power (1.5–9.71%), and performance evaluation criterion (18.24–19.60%), whereas the errors in the computation of heat transfer rate, overall heat transfer coefficient, and effectiveness are not considerable (less than 2.91%).
TL;DR: In this paper, the thermal performance and pressure drop of TiO2-H2O nanofluids in double-tube heat exchangers were investigated, and the influence of the thermal fluid (water) volume flow rates, nanoparticle mass frictions (ω 0.0, 0.1%, 0.3% and 0.5%) on the heat transfer rate was investigated.
TL;DR: In this article, a streamline shape mini-channel cooling plate was used to improve the performance of the inner mini channel cooling plate in the battery thermal management of the electric vehicles.
TL;DR: In this paper, a two-dimensional numerical model based on finite volume method (FVM) was developed with considering natural convection and the calculation results were validated with experimental data.
TL;DR: In this paper, a comprehensive review is carried out of recent advances in the field of ground heat exchangers, including assessments of the effects of system geometric configuration, pipe material, working fluid, and depth of ground-heat exchanger on heat flux, heat transfer coefficient, outlet temperature, thermal resistance, and pressure drop.
TL;DR: In this article, a review categorizes and summarizes the recent development related to the characteristics of flow and heat transfer in printed circuit heat exchanger (PCHE) based on results from experiments and numerical simulations.
TL;DR: In this paper, thermal and hydraulic attributes of an ecofriendly graphene nanofluid flowing within a countercurrent spiral heat exchanger are evaluated, and the results show that the value of effectiveness is much great (higher than 0.85) in all cases under investigation.
TL;DR: In this paper, the authors investigated the performance of a Shell-and-tube heat exchanger operating with CuO/water nanofluid. And the results showed that the proposed new system is economically viable and environmentally friendly.
TL;DR: Simulation results based on well-known twelve benchmark single-objective functions demonstrate the efficiency, effectiveness and robustness of the proposed Falcon Optimization Algorithm in comparison to other algorithms.
TL;DR: In this paper, a numerical analysis of the energy efficiency for a novel solar PVT Loop Heat Pipe (PVT-LHP) employing a novel Micro-channel evaporator and a novel PCM heat storage exchanger is presented.
TL;DR: For a single isolated particle, the effect of overlap displacement on conduction and particle diameter/fluid velocity on convection were comprehensively studied using a CFD-DEM method coupled with heat exchange as mentioned in this paper.
TL;DR: In this article, the combined effects of using nanofluid, a porous insert and corrugated walls on heat transfer, pressure drop and entropy generation inside a heat exchanger duct are investigated.
Abstract: This paper investigates the combined effects of using nanofluid, a porous insert and corrugated walls on heat transfer, pressure drop and entropy generation inside a heat exchanger duct. A series of numerical simulations are conducted for a number of pertinent parameters. It is shown that the waviness of the wall destructively affects the heat transfer process at low wave amplitudes and that it can improve heat convection only after exceeding a certain amplitude. Further, the pressure drop in the duct is found to be strongly influenced by the wave amplitude in a highly non-uniform way. The results, also, show that the second law and heat transfer performances of the system improve considerably by thickening the porous insert and decreasing its permeability. Yet, this is associated with higher pressure drops. It is argued that the hydraulic, thermal and entropic behaviours of the system are closely related to the interactions between a vortex formation near the wavy walls and nanofluid flow through the porous insert. Viscous irreversibilities are shown to be dominant in the core region of duct where the porous insert is placed. However, in the regions closer to the wavy walls, thermal entropy generation is the main source of irreversibility. A number of design recommendations are made on the basis of the findings of this study.
TL;DR: In this article, the authors developed a latent heat storage (LHS) air heater in both charging and discharging processes to find the geometrical and operating conditions for dwelling space heating.
TL;DR: In this paper, a mixed convective Jeffrey nanoliquid stratified flow considering magnetohydrodynamics is formulated, where heat absorption and heat generation aspects in addition to convective conditions and thermal radiation are considered.
TL;DR: In this article, a combined heat and power process consisting of molten carbonate fuel cell, thermoelectric generator, linear Fresnel solar reflector and power turbine is introduced and investigated from energy, exergy and thermodynamic points of view.
TL;DR: In this article, a combined heating and power plant consisting of molten carbonate fuel cell and parabolic trough solar collector with the carbon dioxide capturing process is investigated, and the results show that the electrical, overall and exergy efficiencies of the power plant are 37.68%, 71.29% and 45.13% respectively.
TL;DR: In this article, an alternative cooling system for photovoltaic (PV) panels that includes passing pre-cooled ambient air over back panel surface is experimentally investigated for local conditions of Port Said, Egypt.
TL;DR: In this article, a numerical model was developed by considering the ground temperature gradient in the axial direction and multilayer thermal properties of rock and soil and was used to simulate the temperature distribution and the performance characteristics of coaxial deep borehole heat exchangers.