@article { ISI:000229380600016, title = {Performance assessment of HC-290 as a drop-in substitute to HCFC-22 in a window air conditioner}, journal = {International Journal of Refrigeration - Revue Internationale Du Froid}, volume = {28}, number = {4}, year = {2005}, month = {JUN}, pages = {594-604}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

As per the Montreal Protocol, CFCs and HCFCs are being phased out. HCFC-22 is used in window air conditioners. This paper presents the experimental performance study of a window air conditioner with propane (HC-290), a natural refrigerant, as a drop-in substitute to HCFC-22. Experimental results showed that HC-290 had 6.6\% lower cooling capacity for the lower operating conditions and 9.7\% lower for the higher operating conditions with respect to HCFC-22. The coefficient of performance for HC290 was 7.9\% higher for the lower operating conditions and 2.8\% higher for the higher operating conditions. The energy consumption of the unit with HC-290 was lower in the range 12.4-13.5\% than HCFC-22. The discharge pressures for HC-290 were lower in the range 13.7-18.2\% than HCFC-22. For HC-290, the pressure drop was lower than HCFC-22 in both heat exchangers. This paper also presents simulation results for the heat exchangers of an HCFC-22 window air conditioner with HC-290 as a drop-in substitute. The simulation has been carried out using EVAP-COND, a heat exchanger model developed by NIST [National Institute of Standards and Technology. EVAP-COND: simulation models for finned-tube heat exchangers, Maryland, USA (2003). http://www2.bfrl.nist.gov/software/evap-cond/ [18]]. The simulated evaporator capacities are within +/- 4\% of the experimentally measured cooling capacities for both refrigerants. Simulation results for HC-290 and HCFC-22 are compared. The exit temperatures of HC-290 are lower by 0.3-1.2 degrees C in the condenser and are higher by 2.1-2.4 degrees C in the evaporator than HCFC-22. Evaporating pressures of HC-290 are lower by 2.1-3.3\% as compared to HCFC-22. The pressure drops of HC-290 are lower in both the evaporator and the condenser as compared to HCFC-22. The outlet temperatures of air for HCFC-22 and HC-290 in both heat exchangers are nearly the same. (c) 2005 Elsevier Ltd and IIR. All rights reserved.

}, keywords = {air conditioner, COP, Evaporator, experiment, performance, propane, R-22, simulation, window}, issn = {0140-7007}, doi = {10.1016/j.ijrefrig.2004.09.013}, author = {Devotta, S and Padalkar, AS and Sane, NK} } @article { ISI:000231682900021, title = {Performance assessment of HCFC-22 window air conditioner retrofitted with R-407C}, journal = {Applied Thermal Engineering}, volume = {25}, number = {17-18}, year = {2005}, month = {DEC}, pages = {2937-2949}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

This paper presents the experimental performance analysis of a 1.5 TR window air-conditioner, retrofitted with R-407C, as a substitute to HCFC-22. Experimental results showed that R-407C, for the operating conditions covered in this study, had lower cooling capacity in the range 2.1-7.9\% with respect to HCFC-22. The coefficient of performance for R-407C was lower in the range 7.9-13.5\%. The power consumption of the unit with R-407C was higher in the range 6-7\% than HCFC-22. The discharge pressures for R-407C were higher in the range 11-13\% than HCFC-22. This paper also presents simulation results of heat exchangers of an HCFC-22 window air conditioner retrofitted with R-407C. The simulation has been carried out using EVAP-COND, a heat exchanger model developed by National Institute of Standards and Technology, U.S.A. The simulated evaporator capacities are within +/- 3\% of the experimentally measured cooling capacities for both refrigerants. Simulation results for R-407C and HCFC-22 are compared. The exit temperatures of R-407C are lower by 1.9 degrees C to 5.2 degrees C in the condenser and are higher by 3.2 degrees C to 3.8 degrees C in the evaporator than HCFC-22. Evaporating pressures of R-407C are higher by 4.5-5.3\% as compared to HCFC-22. The pressure drops of R-407C are lower in both the evaporator and the condenser as compared to HCFC-22. The outlet temperatures of air for HCFC-22 and R-407C in both heat exchangers are nearly the same. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {cooling capacity, COP, measurement, performance, power consumption, R-407C}, issn = {1359-4311}, doi = {10.1016/j.applthermaleng.2005.03.002}, author = {Devotta, S and Padalkar, AS and Sane, NK} } @article { ISI:000245334800007, title = {Analysis of a membrane reactor: influence of membrane characteristics and operating conditions}, journal = {International Journal of Chemical Reactor Engineering}, volume = {5}, year = {2007}, month = {APR}, pages = {Article No. A5}, publisher = {BERKELEY ELECTRONIC PRESS}, type = {Article}, address = {2809 TELEGRAPH AVENUE, STE 202, BERKELEY, CA 94705 USA}, abstract = {

Modeling of an esterification reaction in a batch pervaporation membrane reactor (PVMR), and an analysis of the PVMR performance under different reaction conditions for different membrane characteristics are presented. Esterification of ethyl alcohol with acetic acid was considered as the model reaction. The PVMR performance for this reaction could be represented by a 2-step series model. The PVMR performance was similar to that of the batch reactor when both the reactors were in the kinetic regime. However, the performance of the PVMR was superior to that of the batch reactor when both were in the intermediate/equilibrium regime of the reaction. In these regions, the PVMR performance was influenced/limited by the membrane flux and selectivity. The analysis showed that the membrane flux affected the PVMR performance in the intermediate region and the membrane selectivity affected the performance in the equilibrium regime. Further, the limitations introduced by a low-flux membrane could be overcome by appropriate selection of the membrane area and that due to poor selectivity could be compensated to a certain extent by adjusting the feed ratio.

}, keywords = {comparison, Esterification, membrane reactor, performance, pervaporation membrane}, issn = {1542-6580}, author = {Tanna, Nikunj P. and Mayadevi, S.} } @article {43882, title = {Activity tuning of cobalt ferrite nanoparticles anchored on N-doped reduced graphene oxide as a potential oxygen reduction electrocatalyst by Zn substitution in the spinel matrix}, journal = {Chemistry Select}, volume = {2}, year = {2017}, month = {SEP}, pages = {7845-7853}, type = {Article}, abstract = {

Development of highly efficient and durable ORR catalysts by using non-platinum group metals (such as Co, Fe, Mn, and Zn) is a challenging task in the forward path towards the realization of low-cost energy devices in the commercial stream. The present work deals with an effective strategy wherein an efficient Pt-free electrocatalyst for oxygen reduction reaction (ORR) is prepared by stoichiometrically substituting some fraction of Fe with Zn in cobalt ferrite and anchoring these spinel nanoparticles on nitrogen doped reduced graphene oxide (N-rGO). Zn substitution is found to be significantly altering the ratio of Fe2+/Fe3+ in the cobalt ferrite nanocrystal system with a concomitant promotional influence on its electrocatalytic activity towards ORR. The nanoparticle composition with a Co, Fe and Zn molar ratio of 1.0:1.7:0.3, represented by the formula CoFe1.7Zn0.3O4(CFZn(0.3)), supported over N-rGO has shown 10 mV and 20 mV positive shift in the onset and half-wave potentials, respectively, for ORR in 0.1 M KOH in comparison to the nanoparticles of CoFe2O4 supported over N-rGO (CF/N-rGO). The optimum Zn substitution is found to be narrowing down the difference with the state-of-the-art Pt/C for ORR by 100 and 110 mV in terms of the onset and half-wave potentials, respectively. Most significantly, the homemade catalyst is found to be clearly outperforming the Pt catalyst in terms of the limiting current density and electrochemical durability.

}, keywords = {Carbon Nano-fiber, Cathod Catalyst, CoFe2O4, Evolution, Magnetic-properties, Membrane fuel- Cell, Metal-Air Batteries, N-doped graphene, Nanocrystalline, nanocrystals, oxygen reduction reaction, performance, Platinium, solvothermal synthesis, Zn substituted cobalt ferrite}, issn = {2365-6549}, doi = {10.1002/slct.201701684}, author = {Kashyap, Varchaswal and Singh, Santosh K. and Kurungot, Sreekumar} } @article {43899, title = {Copper Cobalt Sulfide Nanosheets Realizing a Promising Electrocatalytic Oxygen Evolution Reaction}, journal = {ACS Catalysis}, volume = {7}, year = {2017}, month = {SEP}, chapter = {5871-5879}, abstract = {

Nanostructured CuCo2S4, a mixed metal thiospinel, is found to be a benchmark electrocatalyst for oxygen evolution reaction (OER) in this study with a low overpotential, a low Tafel slope, a high durability, and a high turnover frequency (TOF) at lower mass loadings. Nanosheets of CuCo2S4 are realized from a hydrothermal synthesis method in which the average thickness of the sheets is found to be in the range of 815 nm. Aggregated nanosheets form a highly open hierarchical structure. When used as an electrocatalyst, CuCo2S4 nanosheets offer an overpotential value of 310 mV at a 10 mA cm(2) current density, which remains consistent for 10000 measured cycles in a 1 M KOH electrolyte. A chronoamperometric study reveals constant oxygen evolution for 12 h at a 10 mV s(-1) scan rate without any degradation of the activity. Furthermore, the calculated mass activity of the CuCo2S4 electrocatalyst is found to be 14.29 A/g and to afford a TOF value of 0.1431 s(-1) at 310 mV at a mass loading of 0.7 mg cm(-2). For comparison, nanostructures of Co3S4 and Cu0.5Co2.5S4 have been synthesized using a similar method followed for CuCo2S4. When compared to the OER activities among these three thiospinels and standard IrO2, CuCo2S4 nanosheets offered the highest OER activities at the same mass loading (0.7 mg/cm(-2)). Extensive X-ray photoelectron spectroscopy and electron paramagnetic resonance analyses for a mechanistic study reveal that introduction of Cu into the Co3S4 lattice enhances the oxygen evolution and kinetics by offering Cu2+ sites for utilitarian adsorption of OH, O, and OOH reactive species and also by offering a highly active high-spin state of octahedral Co3+ for OER catalysis.

}, keywords = {Bifunctional Electrocatalyst, Catalyst, Cuco2s4, Efficient Electrocatalyst, electrocatalyst, Electronic-structure, Nanoparticles, Nanosheet, oxide, oxygen evolution, performance, Recent Progress, Water oxidation, Water Splitting Hydrogen Evolution}, doi = { 10.1021/acscatal.7b01831}, author = {Chauhan, Meenakshi and Reddy, Kasala Prabhakar and Gopinath, Chinnakonda S. and Deka, Sasanka} } @article {43870, title = {NiZn double hydroxide nanosheet-anchored nitrogen-doped graphene enriched with the gamma-NiOOH phase as an activity modulated water oxidation electrocatalyst}, journal = {Nanoscale}, volume = {9}, year = {2017}, month = {SEP}, pages = {12590-12600}, type = {Journal Article}, chapter = {12590-12600}, abstract = {

Herein, we report a facile solvothermal process to synthesize an active electrocatalyst for the oxygen evolution reaction (OER) in an alkaline medium by anchoring nanosheets of a NiZn double hydroxide over nitrogen doped reduced graphene oxide after enriching the system with the γ-NiOOH phase. This catalyst possesses a thin, porous and open layered structure, which makes the system more efficient and accessible for a better electrochemical water oxidation reaction. Moreover, we experimentally demonstrated that incorporation of Zn via a single-step solvothermal method provides an easy approach to obtain plenty of exposed γ-NiOOH phases to make the system more viable for OER with a small overpotential of 290 mV at 10 mA cm-2 and a Tafel slope of 44 mV per decade. In addition to this, the oxophilic nature of Zn in the (Zn)Ni-LDH/N-rGO catalyst helps to improve the long-term stability of the whole system. The obtained results open up possibilities for the design of future robust OER electrocatalysts by the use of very cheap and abundant materials like Ni and Zn in place of expensive Ir and Ru in the present commercial electrocatalysts.

}, keywords = {catalysis, Efficient Electrocatalyst, kinetics, Metal, Nickel-Hydroxide, oxide, Oxygen Evolution Reaction, performance, XPS Spectra, zinc}, issn = {2040-3364}, doi = {10.1039/c7nr02225e}, author = {Nadeema, Ayasha and Dhavale, Vishal M. and Kurungot, Sreekumar} } @article {49251, title = {Iron salicylaldehydate conjugated metal-organic framework for quasi solid-state supercapacitor}, journal = {CHEMICAL ENGINEERING JOURNAL}, volume = {496}, year = {2024}, month = {SEP }, type = {Journal Article}, keywords = {Carbon, conductivity, ELECTROLYTE CONCENTRATION, performance, ROBUST}, issn = {1385-8947}, doi = {10.1016/j.cej.2024.153589}, author = {Mohammed, Abdul Khayum and Pandikassala, Ajmal and Sanchez, Pilar Pena and Gaber, Safa Abdullah and Canossa, Stefano and Kurian, Maria and Xavier, Gigi and He, Yao and Gandara, Felipe and Kurungot, Sreekumar and Shetty, Dinesh} }