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Conference Object Citation - Scopus: 1Parametric Study and Seasonal Simulations of a Solar Powered Adsorption Cooling System(Brazilian Society of Mechanical Sciences and Engineering, 2009) Taylan,O.; Baker,D.K.; Kaftanoʇlu,B.Models of solar-thermal powered adsorption cooling systems with and without heat recovery developed in TRNSYS and results from steady-periodic and seasonal simulations are presented. A normalized model is presented and used to process the seasonal TRNSYS results to investigate the coincidence between the solar-supplied cooling power and cooling load as the relative sizes of the cooling system and storage are varied. The normalized model yields a seasonal solar fraction and seasonal loss fraction (the excess solar-supplied cooling lost to the environment due to insufficient storage). Simulations were run for a zeolite-water adsorbent-refrigerant pair. Hourly weather data for Antalya, Turkey, were used for the transient simulations. Basic trends in performance were investigated as the following parameters were varied: system type (with or without heat recovery); incident radiation; maximum and minimum bed temperatures; condensation temperature; difference between condensation and minimum bed temperatures (bed excess temperature); bed's dead mass; collector type (flat plate vs. evacuated tube); cooling tower type (wet vs. dry); cooling system size; and, storage size. Results for the conditions explored include the following. Steady-periodic simulations show that the system's COP decreases with decreases in radiation and increases with minimum bed and condensation temperatures. Increasing the excess bed temperature increases the system's COP. Systems with an evacuated tube collector and wet cooling tower give higher system COP's than systems with a flat plate collector and dry cooling tower. The increase in system's COP due to decreasing the bed's dead mass and adding heat recovery is quantified. The solar fraction increases and the loss fraction decreases with increases in storage capacity, and both fractions decrease with increases in maximum bed temperature. The required evacuated tube collector area is smaller than the flat plate collector area while the required mass of adsorbent is independent of collector and adsorption cycle types. © 2009 by ABCM.Conference Object Citation - Scopus: 1Enhancing Sustainable Machining of Inconel 718 Using Multi-Walled Carbon Nanotubes and TiO2based Nanofluid Minimum Quantity Lubrication(Elsevier B.V., 2025) Namlu, Ramazan Hakkı; Kaftanoĝlu, BılgınInconel 718 is extensively utilized especially in the aerospace sector due to its outstanding resistance to creep and corrosion, along with its capability to maintain strength at high temperatures. However, its high work hardening rate and low thermal conductivity present significant challenges in machining processes, including the need for extensive use of coolants, shortened tool life, and the necessity for post-processing operations for adequate surface quality, all of which hinder sustainable manufacturing. To address these issues, an innovative cooling/lubrication method, Nanofluid Minimum Quantity Lubrication (NMQL), aims to enhance the sustainable machining of Inconel 718 by minimizing these problems. NMQL involves the aerosolized delivery of nanoparticle-enriched nanofluid oil with compressed air to the cutting zone. In this way, NMQL utilizes the nanoparticles' cooling and lubrication abilities, resulting in lower cutting forces, reduced surface roughness, and decreased tool wear compared to other cooling/lubrication conditions, thereby improving machining performance. This study compares the performance of NMQL in terms of cutting forces, surface roughness and topography, and subsurface microhardness, using Multi-Walled Carbon Nanotubes (MWCNT) and TiO2nanoparticles, with Conventional Cutting Fluids (CCF), aiming to achieve more sustainable machining of Inconel 718. Also, a sustainability assessment was done using Pugh Matrix Approach in order to find the most sustainable cooling option. © 2025 Elsevier B.V., All rights reserved.Article Citation - WoS: 58Citation - Scopus: 66Experimental Investigation of a Natural Zeolite-Water Adsorption Cooling Unit(Elsevier Sci Ltd, 2011) Solmus, Ismail; Kaftanoglu, Bilgin; Yamali, Cemil; Baker, DerekIn this study, a thermally driven adsorption cooling unit using natural zeolite-water as the adsorbent-refrigerant pair has been built and its performance investigated experimentally at various evaporator temperatures. The primary components of the cooling unit are a shell and tube adsorbent bed, an evaporator, a condenser, heating and cooling baths, measurement instruments and supplementary system components. The adsorbent bed is considered to enhance the bed's heat and mass transfer characteristics; the bed consists of an inner vacuum tube filled with zeolite (zeolite tube) inserted into a larger tubular shell. Under the experimental conditions of 45 degrees C adsorption, 150 degrees C desorption, 30 degrees C condenser and 22.5 degrees C, 15 degrees C and 10 degrees C evaporator temperatures, the COP of the adsorption cooling unit is approximately 0.25 and the maximum average volumetric cooling power density (SCR,) and mass specific cooling power density per kg adsorbent (SCP) of the cooling unit are 5.2 kW/m(3) and 7 W/kg, respectively. (C) 2011 Elsevier Ltd. All rights reserved.Article Citation - WoS: 77Citation - Scopus: 90Adsorption properties of a natural zeolite-water pair for use in adsorption cooling cycles(Elsevier Sci Ltd, 2010) Solmus, Ismail; Yamali, Cemil; Kaftanoglu, Bilgin; Baker, Derek; Caglar, AhmetThe equilibrium adsorption capacity of water on a natural zeolite has been experimentally determined at different zeolite temperatures and water vapor pressures for use in an adsorption cooling system. The Dubinin-Astakhov adsorption equilibrium model is fitted to experimental data with an acceptable error limit. Separate correlations are obtained for adsorption and desorption processes as well as a single correlation to model both processes. The isosteric heat of adsorption of water on zeolite has been calculated using the Clausius-Clapeyron equation as a function of adsorption capacity. The cyclic adsorption capacity swing for different condenser, evaporator and adsorbent temperatures is compared with that for the following adsorbent-refrigerant pairs: activated carbon-methanol; silica gel-water; and, zeolite 13X-water. Experimental results show that the maximum adsorption capacity of natural zeolite is nearly 0.12 kg(w)/kg(ad) for zeolite temperatures and water vapor pressures in the range 40-150 degrees C and 0.87-738 kPa. (C) 2009 Elsevier Ltd. All rights reserved.Article Citation - WoS: 43Numerical Investigation of Coupled Heat and Mass Transfer Inside the Adsorbent Bed of an Adsorption Cooling Unit(Elsevier Sci Ltd, 2012) Solmus, Ismail; Rees, D. Andrew S.; Yamali, Cemil; Baker, Derek; Kaftanoglu, BilginIn this study, the influence of several design parameters on the transient distributions of temperature, pressure and amount adsorbed in the radial direction of a cylindrical adsorbent bed of an adsorption cooling unit using silica gel/water have been investigated numerically. For this purpose, a transient one-dimensional local thermal non-equilibrium model that accounts for both internal and external mass transfer resistances has been developed using the local volume averaging method. For the conditions investigated, the validity of the local thermal equilibrium and spatially isobaric bed assumptions have been confirmed. To improve the performance of the bed considered, efforts should be focused on reducing heat transfer resistances and intra-particle (interior) mass transfer resistances but not inter-particle (exterior) mass transfer resistances. (C) 2011 Elsevier Ltd and IIR. All rights reserved.
