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The research pursues a comprehensive understanding of an adiabatic desorption heat and mass transfer mechanism through a microporous hydrophobic hollow fiber membrane. A numerical model of detailed heat and mass transfer in the boundary layer of LiBr solution confined by the hydrophobic layer was proposed; the mass transfer across the membrane layer was clarified to determine the permeability coefficient. Transient experiments verified the proposed models by considering the wide range of temperatures, concentrations, and mass fluxes of the feed LiBr solution. A comparison showed that the experimental heat and mass transfer results were consistent with the theoretical values of adiabatic desorption heat and mass transfer. 

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The proposed study suggests the use of the hydrophobic hollow fiber membrane (HFM) for mass recovery of water vapor between two streams of lithium bromide (LiBr) solution. The proposed configuration, which is different from the conventional ones that have been widely used so far, eliminates the conduction heat transfer process by using double-layered membranes where the water vapor occupies the shell side at vacuum conditions. The conduction heat transfer was neglected, and the solution temperature difference was adequately maintained along the HFM length, and as a result, the mass transfer performance was maximized under the two temperature levels. 

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The iso-thermal conceptual design structure basically consists of two arrays of micro-channels and two hydrophobic flat sheet membranes. A heating source iso-thermally heats an aqueous LiBr solution which flows along an array of micro-channels. A micro-porous hydrophobic flat sheet membrane constrains the flow of liquid LiBr solution so that only water vapor is desorbed out from the solution stream through the pores. A spacer is occupied by the saturated water vapor at the vacuum equilibrium condition. Another hydrophobic membrane is associated with the micro-channel plate to not only prevent the heat from the desorption process but also guide the condensed water on the vertical cooling plate by the hydrophobicity of the membrane. The prevention of heat transfer is of help to enhance the mass transfer performance, and the guidance of the condensed water allows this application for the portable application. 

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Evaporation through the capillary-assisted thin-film is an innovative approach to overcome the challenges in heat transfer enhancement and reduce the charge amount of the refrigerant in refrigeration systems. The present study attempts to illustrate the theoretical details of the capillary-assisted evaporation heat transfer domains on radial parabolic sub-millimeter fin-groove geometries that were partially submerged in a refrigerant, i.e., water. The influence of the water filling level on the evaporation heat transfer domains was investigated with three different fin-groove geometries. Denser fine grooves led to an increase in the number of evaporating thin-film zones, and it was noted that a significant portion of the enhancement in the evaporation heat transfer was contributed majorly by thin-film evaporation developed through the fin-groove structures. The empirical Nusselt correlation was finally obtained in terms of Rayleigh number and fin dimensions.  

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The present study deals with the experimental investigation of capillary-assisted evaporation for nanocomposite-coated plates and finned plates. To promote the capillary action, i.e., climbing level of thin refrigerant film, we proposed two means: Cu-CNT-TiO2 composites coated plate promoted porosity and hydrophilicity as well as thermophysical properties of the heat transfer surface. Machined-finned structures were also developed on the bare copper plate to enlarge the contact area between the thin refrigerant film and the finned walls. The filling level of the refrigerant pool for the semi-flooded evaporation test plate was considered as the main factor to optimize the capillary-assisted evaporation, and as a result, the peak evaporation heat transfers for all the tested plates were found in terms of the filling levels. It was noteworthy that at a certain filling level, the upper body of the test plate was fully occupied by the highest height of the ultra-thin refrigerant film, and the rest underbody was used for the natural convection in the liquid process. 

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Waste heat is a form of renewable energy discarded into the atmosphere. Waste heat-driven absorption systems (i.e., heat pumps and refrigeration systems) have attracted attention as district heating and cooling systems. This study proposes a full-scale waste heat-driven hybrid lithium bromide-water absorption system for the simultaneous generation of available steam and refrigeration effects. The proposed system is a form of an integrated closed thermal cycle between the sub-heat pump and the sub-refrigeration system. It shares a generator and condenser, which allows the system to be more compact and flexible. We first present a description of the full-scale system, designed for a cooling capacity of 350 kW with a steam generation rate of 200 kg/h. The present work examined the effect of part-load conditions on the operating parameters of the full-scale system. The experimental investigation was validated using theoretical simulations, and the payback analysis was suggested to assure the economic validity of the proposed system. 

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A manifold is an essential component of an evacuated tube heat pipe solar collector (ETHPSC) that directly influences the thermal efficiency of a solar heating system. The aim of the present study was to develop and assess the use of a stainless steel-based chevron-hydroformed manifold in ETHPSCs as an alternative to conventional copper-based welded manifolds, which have a high manufacturing cost and short life span, and are easily corroded. This research describes the physical design of the proposed chevron-hydroformed manifold. Numerical modeling using computational fluid dynamics (CFD) was proposed to characterize the heat transfer mechanisms and hydrodynamic behavior of fluid flow through the chevron-hydroformed channels. Field experiments were conducted to compare the performance of the chevron-hydroformed manifold to a conventional copper-based welded manifold. This study discusses the feasibility of stainless steel-based hydroformed manifolds of ETHPSCs in solar heating applications. 

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Battery thermal management system plays an important role in increasing the lifetime of lithium-ion batteries by regulating the temperature level and distribution. In this study, the computational fluid dynamics (CFD) technique predicts the fluid flow and heat transfer characteristics in an air-cooled battery cooling system. The characteristics of airflow drastically vary and furthermore, the pressure drop is reduced using a low-energy consumed fan at the outlet. The experimental apparatus controls the surface temperatures of the 18650 batteries in the range of 30 - 50 ˚C that the battery pack operates safely and stably. 

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This project experimentally investigates the pool boiling heat transfer characteristics of carbon nanotubes-copper (CNT-Cu) nanoparticle-coated heating surfaces. There are two advantages of coating a mixture of infinitesimal CNTs with Cu nanoparticles on the Cu surface: the generation of the active nucleation site density by porous structures and enhanced thermal conductivity of the heating surfaces. Following the experimental analysis in this study, the nucleate boiling heat transfer enhancement was interpreted based on the sintering temperature with surface morphologies and the CNT compositions related to improved pore density. Compared to the bare Cu surface, the maximum enhancement for the boiling heat transfer coefficient and critical heat flux were 3.86 and 1.49, respectively, when a 0.5 CNTs-Cu-coated surface sintered at 800 °C was applied.