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Full-Text Articles in Engineering
Thermoeconomic Optimization Of Cascade Refrigeration System Using Mixed Carbon Dioxide And Hydrocarbons At Low Temperature Circuit, Nasruddin Nasruddin, Arnas Arnas, Ahmad Faqih, Niccolo Giannetti
Thermoeconomic Optimization Of Cascade Refrigeration System Using Mixed Carbon Dioxide And Hydrocarbons At Low Temperature Circuit, Nasruddin Nasruddin, Arnas Arnas, Ahmad Faqih, Niccolo Giannetti
Makara Journal of Technology
Many applications and industrial processes require very low cooling temperature, such as cold storage in the biomedical field, requiring temperature below -80 °C. However, single-cycle refrigeration systems can only achieve the effective cooling temperature of -40 °C and, also, the performance of the cycle will decrease drastically for cooling temperatures lower than -35°C. Currently, most of cascade refrigeration systems use refrigerants that have ozone depletion potential (ODP) and global warming potential (GWP), therefore, in this study, a cascade system is simulated using a mixture of environmentally friendly refrigerants, namely, carbon dioxide and a hydrocarbon (propane, ethane or ethylene) as the …
Influence Of Dynamic Factors On Nonwetting Fluid Snap-Off In Pores, Wen Deng, Matthew Balhoff, M. Bayani Cardenas
Influence Of Dynamic Factors On Nonwetting Fluid Snap-Off In Pores, Wen Deng, Matthew Balhoff, M. Bayani Cardenas
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Snap-off is an important dynamic multiphase flow phenomenon which occurs in porous media. It plays a dominant role in the residual trapping and mobilization/immobilization of nonwetting fluids such as hydrocarbons or CO₂. Current studies, applications, and threshold criteria of snap-off are mostly based on static or equilibrium conditions. Thus, the dynamics of snap-off which is relevant for many real world applications has rarely been systematically studied. While a static criterion indicates the snap-off potential for nonwetting fluids, the competition between the time required for snap-off and the local pore throat capillary number determines whether snap-off actually occurs. Using a theoretical …
Improving Energy Efficiency And Environmental Sustainability Of Commercial Insulation, Celine F. Manoosingh, James Mihelcic, Manjriker Gunaratne
Improving Energy Efficiency And Environmental Sustainability Of Commercial Insulation, Celine F. Manoosingh, James Mihelcic, Manjriker Gunaratne
Department of Civil Engineering & Construction Faculty Research & Publications
With increasingly stringent energy standards set in place by the Department of Energy, energy efficiency is becoming a paramount concern to manufacturers of appliances. Additionally, the production and disposal of the voluminous amount of polyurethane foam commonly utilized as insulation in refrigeration units poses a significant environmental challenge. In this context, this study investigated an alternative insulation for use in commercial refrigerator/freezer units. A prototype exploring the use of evacuated packets of pyrogenic silica substituting for conventional insulation was assessed. Assessment criteria included experimental comparison of heat transfer characteristics and the energy efficiency of the new insulation as well as …
Chemical And Hydrodynamic Mechanisms For Long-Term Geological Carbon Storage, Susan J. Altman, Wen Deng, For Full List Of Authors, See Publisher's Website.
Chemical And Hydrodynamic Mechanisms For Long-Term Geological Carbon Storage, Susan J. Altman, Wen Deng, For Full List Of Authors, See Publisher's Website.
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Geological storage of CO₂ (GCS), also referred to as carbon sequestration, is a critical component for decreasing anthropogenic CO₂ atmospheric emissions. Stored CO₂ will exist as a supercritical phase, most likely in deep, saline, sedimentary reservoirs. Research at the Center for Frontiers of Subsurface Energy Security (CFSES), a Department of Energy, Energy Frontier Research Center, provides insights into the storage process. The integration of pore-scale experiments, molecular dynamics simulations, and study of natural analogue sites has enabled understanding of the efficacy of capillary, solubility, and dissolution trapping of CO₂ for GCS. Molecular dynamics simulations provide insight on relative wetting of …
Geochemistry And Inorganic Carbon Transport Of A Glacial Till Drumlin At A Road Salt Facility, Houbao Li
Geochemistry And Inorganic Carbon Transport Of A Glacial Till Drumlin At A Road Salt Facility, Houbao Li
Open Access Dissertations
Investigations were conducted at a salt/premix storage facility lying on top of a glacial drumlin near the coastline in eastern Massachusetts, to characterize salt contaminated groundwater. Groundwater hydrogeochemical variations at different depths were determined based on ten years of monthly or quarterly water quality data from 54 monitoring wells. Groundwater was grouped in three water categories – shallow, middle and deep. Hydrogeochemical characterization indicates that the dominant water types are Na-Cl, Na-Ca-Cl and Ca-HCO3 from the shallow to deep water group. Rock weathering is the dominant hydrogeochemical process for deep water group, whereas salt water percolation and cation exchange control …
Microscopic Assessment Of Transportation Emissions On Limited Access Highways, Hatem Abou-Senna
Microscopic Assessment Of Transportation Emissions On Limited Access Highways, Hatem Abou-Senna
Electronic Theses and Dissertations
On-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have estimated emissions using one average speed and volume on a long stretch of roadway. With MOVES, there is an opportunity for higher precision and accuracy. Integrating a microscopic traffic simulation model (such …