A mathematical study is developed for the electro-osmotic flow of a nonNewtonian fluid in a wavy microchannel in which a Bingham viscoplastic fluid model is considered.For electric potential distributions,a Poisson-Bo...A mathematical study is developed for the electro-osmotic flow of a nonNewtonian fluid in a wavy microchannel in which a Bingham viscoplastic fluid model is considered.For electric potential distributions,a Poisson-Boltzmann equation is employed in the presence of an electrical double layer(EDL).The analytical solutions of dimensionless boundary value problems are obtained with the Debye-Huckel theory,the lubrication theory,and the long wavelength approximations.The effects of the Debyelength parameter,the plug flow width,the Helmholtz-Smoluchowski velocity,and the Joule heating on the normalized temperature,the velocity,the pressure gradient,the volumetric flow rate,and the Nusselt number for heat transfer are evaluated in detail using graphs.The analysis provides important findings regarding heat transfer in electroosmotic flows through a wavy microchannel.展开更多
Apartments account for over 60%of total residential buildings and consume a significant portion of primary energy in South Korea.Various energy efficiency measures have been implemented for both new apartment construc...Apartments account for over 60%of total residential buildings and consume a significant portion of primary energy in South Korea.Various energy efficiency measures have been implemented for both new apartment constructions and existing apartment retrofits.Old apartment structures have poor thermal performances,resulting in a high energy consumption.The South Korean government initiated retrofitting projects to improve the energy efficiency in old apartments.Apartment owners typically replace old windows with high-performance windows;however,there is still a demand for better and more innovative retrofit methods for a highly improved energy efficiency.This paper proposes an advanced double-skin façade(DSF)system to replace existing balcony windows in old apartments.Considering the cold climate conditions of Seoul,South Korea,it mainly discusses heating energy savings.Three case models were developed:Base-Case with existing apartment,Case-1 with typical retrofitting,and Case-2 with the proposed DSF system.The EnergyPlus simulation program was used to develop simulation models for a floor radiant heating system.A typical gas boiler was selected for low-temperature radiant system modeling.The air flow network method was used to model the proposed DSF system.Five heating months,i.e.,November to March,and one representative day,i.e.,January 24,were selected for detailed analysis.The main heat loss areas consist of windows,walls,and infiltration.The results reveal that the apartment with the DSF retrofit saves 38.8%on the annual heating energy compared to the Base-Case and 35.2%compared to Case-1.展开更多
文摘A mathematical study is developed for the electro-osmotic flow of a nonNewtonian fluid in a wavy microchannel in which a Bingham viscoplastic fluid model is considered.For electric potential distributions,a Poisson-Boltzmann equation is employed in the presence of an electrical double layer(EDL).The analytical solutions of dimensionless boundary value problems are obtained with the Debye-Huckel theory,the lubrication theory,and the long wavelength approximations.The effects of the Debyelength parameter,the plug flow width,the Helmholtz-Smoluchowski velocity,and the Joule heating on the normalized temperature,the velocity,the pressure gradient,the volumetric flow rate,and the Nusselt number for heat transfer are evaluated in detail using graphs.The analysis provides important findings regarding heat transfer in electroosmotic flows through a wavy microchannel.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20172010000370).
文摘Apartments account for over 60%of total residential buildings and consume a significant portion of primary energy in South Korea.Various energy efficiency measures have been implemented for both new apartment constructions and existing apartment retrofits.Old apartment structures have poor thermal performances,resulting in a high energy consumption.The South Korean government initiated retrofitting projects to improve the energy efficiency in old apartments.Apartment owners typically replace old windows with high-performance windows;however,there is still a demand for better and more innovative retrofit methods for a highly improved energy efficiency.This paper proposes an advanced double-skin façade(DSF)system to replace existing balcony windows in old apartments.Considering the cold climate conditions of Seoul,South Korea,it mainly discusses heating energy savings.Three case models were developed:Base-Case with existing apartment,Case-1 with typical retrofitting,and Case-2 with the proposed DSF system.The EnergyPlus simulation program was used to develop simulation models for a floor radiant heating system.A typical gas boiler was selected for low-temperature radiant system modeling.The air flow network method was used to model the proposed DSF system.Five heating months,i.e.,November to March,and one representative day,i.e.,January 24,were selected for detailed analysis.The main heat loss areas consist of windows,walls,and infiltration.The results reveal that the apartment with the DSF retrofit saves 38.8%on the annual heating energy compared to the Base-Case and 35.2%compared to Case-1.
