An updated review of nanofluids in various heat transfer devices

Journal of Thermal Analysis and Calorimetry https://doi.org/10.1007/s10973-020-09760-2 An updated review of nanofluids in various heat transfer devices Eric C. Okonkwo1 · Ifeoluwa Wole‑Osho2 · Ismail W. Almanassra1 · Yasser M. Abdullatif1 · Tareq Al‑Ansari1,3 Received: 12 March 2020 / Accepted: 27 April 2020 © The Author(s) 2020 Abstract The field of nanofluids has received interesting attention since the concept of dispersing nanoscaled particles into a fluid was first introduced in the later part of the twentieth century. This is evident from the increased number of studies related to nanofluids published annually. The increasing attention on nanofluids is primarily due to their enhanced thermophysical properties and their ability to be incorporated into a wide range of thermal applications ranging from enhancing the effectiveness of heat exchangers used in industries to solar energy harvesting for renewable energy production. Owing to the increasing number of studies relating to nanofluids, there is a need for a holistic review of the progress and steps taken in 2019 concerning their application in heat transfer devices. This review takes a retrospective look at the year 2019 by reviewing the progress made in the area of nanofluids preparation and the applications of nanofluids in various heat transfer devices such as solar collectors, heat exchangers, refrigeration systems, radiators, thermal storage systems and electronic cooling. This review aims to update readers on recent progress while also highlighting the challenges and future of nanofluids as the next-generation heat transfer fluids. Finally, a conclusion on the merits and demerits of nanofluids is presented along with recommendations for future studies that would mobilise the rapid commercialisation of nanofluids. Keywords Nanofluids · Heat transfer · Nanoparticles · Solar collector · Heat exchangers Abbreviations AARS Ammonia absorption refrigeration system AFM Atomic force microscopy AG Arabic gum ANN Artificial neural network CA Citric acid CFD Computational fluid dynamics CHF Critical heat flux CMC Carboxymethyl cellulose CNT Carbon nanotubes COP Coefficient of performance * Eric C. Okonkwo * Tareq Al‑Ansari 1 Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Education City, Doha, Qatar 2 Department of Energy Systems Engineering, Cyprus International University, North Cyprus, Turkey 3 Division of Engineering Management and Decision Sciences, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Education City, Doha, Qatar CPC Compound parabolic collectors CPU Central processing unit CTAB Cetrimonium bromide DAPTC Direct absorption parabolic trough collector DASC Direct absorption solar collector DI Deionised DLS Dynamic light scattering EBT Eriochrome Black T EDX Energy-dispersive X-ray spectroscopy ETSC Evacuated tube solar collector FESEM Field emission scanning electron microscope FPC Flat plate collector FTIR Fourier-transform infrared spectroscopy GNP Graphene nanoplatelets HPSC Heat pipe solar collector HPSWH Heat pipe solar water heater HX Heat exchangers LFR Linear Fresnel reflectors MAAFG Microwave-assisted acid-functionalised graphene MCHS Microchannel heat sink MLG Multilayer graphene MWCNT Multiwall carbon nanotubes nePCM Nano-encapsulated phase change materials 13 Vol.:(0123456789) E. C. Okonkwo et al. OA Oleylamine PAO Polyalphaolefin PCM Phase change materials PEG Polyethylene glycol PTSC Parabolic trough solar collectors PV Photovoltaic PVA Polyvinyl alcohol PVP Polyvinylpyrrolidone PVT Photovoltaic thermal collectors SDBS Sodium dodecylbenzene sulphonate SDS Sodium dodecyl sulphate SEM Scanning electron microscope SWCNT Single-wall carbon nanotube TEM Transmission electron microscope TES Thermal energy storage VARS Vapour absorption refrigeration system VCRS Vapour compression refrigeration systems Vol% Volume per cent XRD X-ray powder diffraction ZVI Zero-valent iron Introduction Energy is a very important quantitative property that must be transferred before any system can perform work. The transfer of energy can be done by either work or heat [1]. Heat is transferred from one system to another when there exists a temperature difference between the two systems and travels from high to low temperatures [2]. The science that describes the means and rate in which thermal (heat) energy is transferred is known as heat transfer. Heat transfer applications are experienced in our daily life; the human body, for instance, is constantly emitting heat, and humans adjust their body temperature to suit environmental conditions using clothing. Heat transfer is also used in our buildings to regulate temperature [3] and is necessary for cooking, refrigeration and drying. It is also directly applied in car radiators [4] and for temperature control in electronic devices [5]. Heat transfer is used in solar thermal collectors to convert solar energy to heat and power [6, 7] and used in thermal control elements in spacecraft [8]. In many of these devices, heat needs to be dissipated at a rapid rate to ensure effective operation and maximum efficiency within the system [9]. As technology evolves, devices have become smaller and thus require better thermal management. Essentially, the more compact the size, the larger the requirement for effective cooling technology [10]. Therefore, heat transfer enhancement is a very important area in thermal engineering. Several techniques have been considered to improve the heat transfer coefficient between the working fluids and the fluid contact surfaces [11, 12]. Conventional heat transfer fluids such as water, thermal oils and ethylene glycol/water 13 have some limitations as their thermal properties are quite low when compared to those of solids, as shown in Fig. 1. The improvement in the thermal properties of these fluids through the addition of nanoscaled particles has led to an evolution in the study of heat transfer fluids. The suspension of these solid particles in the base fluid enhances the energy transmission in the fluid leading to improved thermal conductivity properties and better heat transfer characteristics [13]. The resultant fluids have been seen to possess higher values of thermal conductivity [14, 15]. Choi and Eastman [15] were the first to name such fluids as nanofluids. Nanofluids are the engineered colloidal suspension of nanoscaled particles (10–100 nm) in a base fluid [16]. These particles are generally metals, metallic oxides or other carbon-based elements. Over a century ago, Maxwell [17] was the first to discuss the suspension of micro-scaled particles into a fluid. However, microparticles settled rapidly in the fluid leading to abrasion and clogging in the flow channel, limiting further research into suspensions in fluids. Furthermore, these fluids did not exhibit (...truncated)