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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: 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.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: 16Citation - Scopus: 19Cop Trends for Ideal Thermal Wave Adsorption Cooling Cycles With Enhancements(Elsevier Sci Ltd, 2012) Taylan, Onur; Baker, Derek K.; Kaftanoglu, BilginModels are presented for ideal thermal wave adsorption cooling cycles without mass recovery, with adiabatic mass recovery and with isothermal mass recovery. Coefficient of performance (COP) values obtained from simulations are compared with the results of a reversible cycle and previously developed models for a simple cycle and heat recovery cycle with two spatially isothermal beds (2SIB). The effects of maximum and minimum bed temperatures, bed's dead mass, and condensation and evaporation temperatures on COP were investigated. The thermal wave cycle has significantly higher COP's than the simple and 2SIB cycles. For the conditions investigated, adding mass recovery to the thermal wave cycle does not affect its COP significantly. The COP of the thermal wave cycle increases with increasing maximum bed and evaporation temperatures and decreasing minimum bed and condensation temperatures. Unlike for the simple and 2SIB cycles, variations in the bed's dead mass have minimal impact on COP. (C) 2010 Elsevier Ltd and IIR. All rights reserved.
