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Zhenglian Wang - One of the best experts on this subject based on the ideXlab platform.
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Dynamics of Family Households and elderly living arrangements in China, 1990–2010
China Population and Development Studies, 2018Co-Authors: Yi Zeng, Zhenglian WangAbstract:This article presents analyses on dynamics of Family Households and elderly living arrangements in China mainly based on the micro data of 2010, 2000 and 1990 censuses. We demonstrate and discuss the trends and rural–urban differentials of largely declined Household size, quickly increasing one-person and one-couple-only Households, substantially increased proportions of elderly living alone or with spouse only. It is strikingly interesting that proportion of three-generation Family Households increased by 18.9% in rural area but decreased by 23.7% in urban areas in 2010 compared to 1990, due to rural–urban differences in demographic effects of large fertility decline and socioeconomic/attitude changes. We also present and discuss two interesting demographic phenomenon which were relatively overlooked in the literature. First, increase in number of Households is much larger than population growth, due to shrinking of the Household size and decomposition of larger families into smaller ones, and very much slowed-down population growth. Second, increases in numbers of elderly (especially oldest-old) who live alone or with spouse only are dramatically larger than the increase in the corresponding proportions, due to the effects of rapid population aging, while later and larger birth cohorts become old. Such trends have important implications for the analyses on the current and future market demands of the products and services, of which Households are the consumption units. We recommend that the studies on home-based energy use and sustainable development should be based on analyses of Family Household dynamics rather than population growth.
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U.S. Family Household Momentum and Dynamics: Projections at the National Level
Household and Living Arrangement Projections, 2013Co-Authors: Yi Zeng, Kenneth C. Land, Zhenglian WangAbstract:In this chapter, we apply the ProFamy extended cohort-component model to project U.S. Households by race from 2000 to 2050. We address important questions such as: How may demographic changes alter the number and proportion of different types and sizes of Households in future years? How may demographic changes affect the living arrangements of elderly persons? We also provide evidence of “Family Household momentum,” which is similar to the well-known phenomenon of population momentum.
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U.S. Family Household Momentum and Dynamics: An Extension and Application of the ProFamy Method
Population Research and Policy Review, 2006Co-Authors: Zeng Yi, Kenneth C. Land, Zhenglian Wang, Danan GuAbstract:The classic headship-rate method for demographic projections of Households is not linked to demographic rates, projects a few Household types without size, and does not deal with Household members other than heads. By comparison, the ProFamy method uses demographic rates as input and projects more detailed Household types, sizes, and living arrangements for all members of the population. Tests of projections from 1990 to 2000 using ProFamy and based on observed U.S. demographic rates before 1991 show that discrepancies between our projections and census observations in 2000 are reasonably small, validating the new method. Using data from national surveys and vital statistics, census microfiles, and the ProFamy method, we prepare projections of U.S. Households from 2000 to 2050. Medium projections as well as projections based on smaller and larger Family scenarios with corresponding combinations of assumptions of marriage/union formation and dissolution, fertility, mortality, and international migration are performed to analyze future trends of U.S. Households and their possible higher and lower bounds, as well as enormous racial differentials. To our knowledge, the Household projections reported in this article are the first to have found empirical evidence of Family Household momentum and to have provided informative low and high bounds of various indices of projected future Households and living arrangements distributions based on possible changes in demographic parameters.
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u s Family Household momentum and dynamics an extension and application of the profamy method
Population Research and Policy Review, 2006Co-Authors: Kenneth C. Land, Zhenglian WangAbstract:The classic headship-rate method for demographic projections of Households is not linked to demographic rates, projects a few Household types without size, and does not deal with Household members other than heads. By comparison, the ProFamy method uses demographic rates as input and projects more detailed Household types, sizes, and living arrangements for all members of the population. Tests of projections from 1990 to 2000 using ProFamy and based on observed U.S. demographic rates before 1991 show that discrepancies between our projections and census observations in 2000 are reasonably small, validating the new method. Using data from national surveys and vital statistics, census microfiles, and the ProFamy method, we prepare projections of U.S. Households from 2000 to 2050. Medium projections as well as projections based on smaller and larger Family scenarios with corresponding combinations of assumptions of marriage/union formation and dissolution, fertility, mortality, and international migration are performed to analyze future trends of U.S. Households and their possible higher and lower bounds, as well as enormous racial differentials. To our knowledge, the Household projections reported in this article are the first to have found empirical evidence of Family Household momentum and to have provided informative low and high bounds of various indices of projected future Households and living arrangements distributions based on possible changes in demographic parameters. Copyright Springer 2006
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Estimating time-varying sex-age-specific o/e rates of marital status transitions in Family Household projection or simulation
Demographic Research, 2004Co-Authors: Yi Zeng, Eric Stallard, Zhenglian WangAbstract:This article presents a procedure for estimating time-varying sex-age-specific occurrence/exposure (o/e) rates of marital status transitions to ensure that the projected life course propensities of marriage/union formation and dissolution are achieved consistently in the one-sex Family status life table model. Procedures for estimating time-varying sex-age-specific marital status transition o/e rates that are consistent with the two-sex constraints and projected summary measures of marriage/union formation and dissolution in the future years in the two-sex Family Household projection model is proposed. The procedures proposed in this article are practically useful and can be applied in both macro and micro models for Family Household projections or simulations that need time-varying sex-age-specific o/e rates of marital status transitions.
Søren Knudsen Kær - One of the best experts on this subject based on the ideXlab platform.
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application of an improved operational strategy on a pbi fuel cell based residential system for danish single Family Households
Applied Thermal Engineering, 2013Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:Abstract A proposed residential energy system based on the PBI (Polybenzimidazole) fuel cell technology is analyzed in terms of operational performance. Conventional operational strategies, such as heat-led and electricity-led, are applied to the simulated system to investigate their performance characteristics. Based on these findings, an improved operational strategy is formulated and applied in an attempt to minimize the shortcomings of conventional strategies. System parameters, such as electrical and thermal efficiencies, heat dumping, and import/export of electricity, are analyzed. The applied load profile is based on average data for a single-Family Household in Denmark and includes consumption data for electricity and heat demands. The study analyzes the potential of the proposed system on market penetration in the area of residential heat-and-power generation and whether this deployment can be justified as compared to other micro-CHP system technologies. The most important findings of this research study indicate that in comparison to non-fuel cell-based micro-CHP systems, such as Stirling Engine-based systems, the proposed system has significantly higher efficiencies. Moreover, the lower heat-to-power ratios allow the system to avoid high thermal surpluses throughout the whole annual operational profile.
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modeling and parametric study of a 1 kwe ht pemfc based residential micro chp system
International Journal of Hydrogen Energy, 2011Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:Abstract A detailed thermodynamic, kinetic and geometric model of a micro-CHP (Combined-Heat-and-Power) residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC) technology is developed, implemented and validated. HT-PEMFC technology is investigated as a possible candidate for fuel cell-based residential micro-CHP systems, since it can operate at higher temperature than Nafion-based fuel cells, and therefore can reach higher cogeneration efficiencies. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-Family Household. A complete fuel processing subsystem, with all necessary balance-of-plant components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system’s synthesis/design and operational pattern is analyzed by means of a parametric study. The parametric study is conducted to determine the most viable system/component design based on maximizing total system efficiency, without violating the requirements of the system. Four decision variables (steam-to-carbon ratio, fuel cell operating temperature, combustor temperature and hydrogen stoichiometry) were parameterized within feasible limits to provide insight on their effect on the overall performance of the proposed system under study and also to provide input on more efficient design in the future. The system is designed to provide maximum loads of 1 kW e and 2 kW th . A sensitivity analysis is applied to investigate the influence of the most important parameters on the simulated performance of the system.
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Modeling and off-design performance of a 1kWe HT-PEMFC (high temperature-proton exchange membrane fuel cell)-based residential micro-CHP (combined-heat-and-power) system for Danish single-Family Households
Energy, 2011Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:A novel proposal for the modeling and operation of a micro-CHP (combined-heat-and-power) residential system based on HT-PEMFC (High Temperature-Proton Exchange Membrane Fuel Cell) technology is described and analyzed to investigate its commercialization prospects. An HT-PEMFC operates at elevated temperatures, as compared to Nafion-based PEMFCs and therefore can be a significant candidate for cogeneration residential systems. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-Family Household. A complete fuel processing subsystem, with all necessary BOP (balance-of-plant) components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system is simulated in LabVIEW™ environment to provide the ability of Data Acquisition of actual components and thereby more realistic design in the future. A part-load study has been conducted to indicate performance characteristics at off-design conditions. The system is sized to provide realistic dimensioning of the actual system.
Alexandros Arsalis - One of the best experts on this subject based on the ideXlab platform.
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Parametric study and cost analysis of a solar-heating-and-cooling system for detached single-Family Households in hot climates
Solar Energy, 2015Co-Authors: Alexandros Arsalis, Andreas N. AlexandrouAbstract:Abstract A solar-heating-and-cooling (SHC) system, consisting of a flat-plate solar collector array, a hot water storage tank, and an absorption chiller unit is designed and modeled to satisfy thermal loads (space heating, domestic hot water, and space cooling). The system is applied for Nicosia, Cyprus, a location with prolonged summer-like conditions, where heating demand is moderate, while space cooling demand is comparatively very high. The study investigates the potential of a solar system installed and operated onsite in a detached single-Family Household to satisfy all necessary thermal loads. The hot water storage tank is also connected to an auxiliary heater (diesel-fired boiler) to supplement solar heating, when needed. The main purpose of the study is to model the overall system and contact a parametric study that will determine the optimum economic system performance in terms of design parameters. The system is compared, through a cost analysis, to an electric heat pump (EHP) system. It is found that the optimum system combination of solar collector area and volumetric capacity of the hot water storage tank is 70 m2 and 2000 L, respectively. The total annualized cost (in USD) for the optimum SHC system is $3,719. The sensitivity analysis showed that the SHC system would be unfavorable to compete with EHP technology, if the solar collector cost is above $360/m2.
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application of an improved operational strategy on a pbi fuel cell based residential system for danish single Family Households
Applied Thermal Engineering, 2013Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:Abstract A proposed residential energy system based on the PBI (Polybenzimidazole) fuel cell technology is analyzed in terms of operational performance. Conventional operational strategies, such as heat-led and electricity-led, are applied to the simulated system to investigate their performance characteristics. Based on these findings, an improved operational strategy is formulated and applied in an attempt to minimize the shortcomings of conventional strategies. System parameters, such as electrical and thermal efficiencies, heat dumping, and import/export of electricity, are analyzed. The applied load profile is based on average data for a single-Family Household in Denmark and includes consumption data for electricity and heat demands. The study analyzes the potential of the proposed system on market penetration in the area of residential heat-and-power generation and whether this deployment can be justified as compared to other micro-CHP system technologies. The most important findings of this research study indicate that in comparison to non-fuel cell-based micro-CHP systems, such as Stirling Engine-based systems, the proposed system has significantly higher efficiencies. Moreover, the lower heat-to-power ratios allow the system to avoid high thermal surpluses throughout the whole annual operational profile.
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modeling and parametric study of a 1 kwe ht pemfc based residential micro chp system
International Journal of Hydrogen Energy, 2011Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:Abstract A detailed thermodynamic, kinetic and geometric model of a micro-CHP (Combined-Heat-and-Power) residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC) technology is developed, implemented and validated. HT-PEMFC technology is investigated as a possible candidate for fuel cell-based residential micro-CHP systems, since it can operate at higher temperature than Nafion-based fuel cells, and therefore can reach higher cogeneration efficiencies. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-Family Household. A complete fuel processing subsystem, with all necessary balance-of-plant components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system’s synthesis/design and operational pattern is analyzed by means of a parametric study. The parametric study is conducted to determine the most viable system/component design based on maximizing total system efficiency, without violating the requirements of the system. Four decision variables (steam-to-carbon ratio, fuel cell operating temperature, combustor temperature and hydrogen stoichiometry) were parameterized within feasible limits to provide insight on their effect on the overall performance of the proposed system under study and also to provide input on more efficient design in the future. The system is designed to provide maximum loads of 1 kW e and 2 kW th . A sensitivity analysis is applied to investigate the influence of the most important parameters on the simulated performance of the system.
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Modeling and off-design performance of a 1kWe HT-PEMFC (high temperature-proton exchange membrane fuel cell)-based residential micro-CHP (combined-heat-and-power) system for Danish single-Family Households
Energy, 2011Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:A novel proposal for the modeling and operation of a micro-CHP (combined-heat-and-power) residential system based on HT-PEMFC (High Temperature-Proton Exchange Membrane Fuel Cell) technology is described and analyzed to investigate its commercialization prospects. An HT-PEMFC operates at elevated temperatures, as compared to Nafion-based PEMFCs and therefore can be a significant candidate for cogeneration residential systems. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-Family Household. A complete fuel processing subsystem, with all necessary BOP (balance-of-plant) components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system is simulated in LabVIEW™ environment to provide the ability of Data Acquisition of actual components and thereby more realistic design in the future. A part-load study has been conducted to indicate performance characteristics at off-design conditions. The system is sized to provide realistic dimensioning of the actual system.
Kenneth C. Land - One of the best experts on this subject based on the ideXlab platform.
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U.S. Family Household Momentum and Dynamics: Projections at the National Level
Household and Living Arrangement Projections, 2013Co-Authors: Yi Zeng, Kenneth C. Land, Zhenglian WangAbstract:In this chapter, we apply the ProFamy extended cohort-component model to project U.S. Households by race from 2000 to 2050. We address important questions such as: How may demographic changes alter the number and proportion of different types and sizes of Households in future years? How may demographic changes affect the living arrangements of elderly persons? We also provide evidence of “Family Household momentum,” which is similar to the well-known phenomenon of population momentum.
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U.S. Family Household Momentum and Dynamics: An Extension and Application of the ProFamy Method
Population Research and Policy Review, 2006Co-Authors: Zeng Yi, Kenneth C. Land, Zhenglian Wang, Danan GuAbstract:The classic headship-rate method for demographic projections of Households is not linked to demographic rates, projects a few Household types without size, and does not deal with Household members other than heads. By comparison, the ProFamy method uses demographic rates as input and projects more detailed Household types, sizes, and living arrangements for all members of the population. Tests of projections from 1990 to 2000 using ProFamy and based on observed U.S. demographic rates before 1991 show that discrepancies between our projections and census observations in 2000 are reasonably small, validating the new method. Using data from national surveys and vital statistics, census microfiles, and the ProFamy method, we prepare projections of U.S. Households from 2000 to 2050. Medium projections as well as projections based on smaller and larger Family scenarios with corresponding combinations of assumptions of marriage/union formation and dissolution, fertility, mortality, and international migration are performed to analyze future trends of U.S. Households and their possible higher and lower bounds, as well as enormous racial differentials. To our knowledge, the Household projections reported in this article are the first to have found empirical evidence of Family Household momentum and to have provided informative low and high bounds of various indices of projected future Households and living arrangements distributions based on possible changes in demographic parameters.
-
u s Family Household momentum and dynamics an extension and application of the profamy method
Population Research and Policy Review, 2006Co-Authors: Kenneth C. Land, Zhenglian WangAbstract:The classic headship-rate method for demographic projections of Households is not linked to demographic rates, projects a few Household types without size, and does not deal with Household members other than heads. By comparison, the ProFamy method uses demographic rates as input and projects more detailed Household types, sizes, and living arrangements for all members of the population. Tests of projections from 1990 to 2000 using ProFamy and based on observed U.S. demographic rates before 1991 show that discrepancies between our projections and census observations in 2000 are reasonably small, validating the new method. Using data from national surveys and vital statistics, census microfiles, and the ProFamy method, we prepare projections of U.S. Households from 2000 to 2050. Medium projections as well as projections based on smaller and larger Family scenarios with corresponding combinations of assumptions of marriage/union formation and dissolution, fertility, mortality, and international migration are performed to analyze future trends of U.S. Households and their possible higher and lower bounds, as well as enormous racial differentials. To our knowledge, the Household projections reported in this article are the first to have found empirical evidence of Family Household momentum and to have provided informative low and high bounds of various indices of projected future Households and living arrangements distributions based on possible changes in demographic parameters. Copyright Springer 2006
Mads Pagh Nielsen - One of the best experts on this subject based on the ideXlab platform.
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application of an improved operational strategy on a pbi fuel cell based residential system for danish single Family Households
Applied Thermal Engineering, 2013Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:Abstract A proposed residential energy system based on the PBI (Polybenzimidazole) fuel cell technology is analyzed in terms of operational performance. Conventional operational strategies, such as heat-led and electricity-led, are applied to the simulated system to investigate their performance characteristics. Based on these findings, an improved operational strategy is formulated and applied in an attempt to minimize the shortcomings of conventional strategies. System parameters, such as electrical and thermal efficiencies, heat dumping, and import/export of electricity, are analyzed. The applied load profile is based on average data for a single-Family Household in Denmark and includes consumption data for electricity and heat demands. The study analyzes the potential of the proposed system on market penetration in the area of residential heat-and-power generation and whether this deployment can be justified as compared to other micro-CHP system technologies. The most important findings of this research study indicate that in comparison to non-fuel cell-based micro-CHP systems, such as Stirling Engine-based systems, the proposed system has significantly higher efficiencies. Moreover, the lower heat-to-power ratios allow the system to avoid high thermal surpluses throughout the whole annual operational profile.
-
modeling and parametric study of a 1 kwe ht pemfc based residential micro chp system
International Journal of Hydrogen Energy, 2011Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:Abstract A detailed thermodynamic, kinetic and geometric model of a micro-CHP (Combined-Heat-and-Power) residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC) technology is developed, implemented and validated. HT-PEMFC technology is investigated as a possible candidate for fuel cell-based residential micro-CHP systems, since it can operate at higher temperature than Nafion-based fuel cells, and therefore can reach higher cogeneration efficiencies. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-Family Household. A complete fuel processing subsystem, with all necessary balance-of-plant components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system’s synthesis/design and operational pattern is analyzed by means of a parametric study. The parametric study is conducted to determine the most viable system/component design based on maximizing total system efficiency, without violating the requirements of the system. Four decision variables (steam-to-carbon ratio, fuel cell operating temperature, combustor temperature and hydrogen stoichiometry) were parameterized within feasible limits to provide insight on their effect on the overall performance of the proposed system under study and also to provide input on more efficient design in the future. The system is designed to provide maximum loads of 1 kW e and 2 kW th . A sensitivity analysis is applied to investigate the influence of the most important parameters on the simulated performance of the system.
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Modeling and off-design performance of a 1kWe HT-PEMFC (high temperature-proton exchange membrane fuel cell)-based residential micro-CHP (combined-heat-and-power) system for Danish single-Family Households
Energy, 2011Co-Authors: Alexandros Arsalis, Mads Pagh Nielsen, Søren Knudsen KærAbstract:A novel proposal for the modeling and operation of a micro-CHP (combined-heat-and-power) residential system based on HT-PEMFC (High Temperature-Proton Exchange Membrane Fuel Cell) technology is described and analyzed to investigate its commercialization prospects. An HT-PEMFC operates at elevated temperatures, as compared to Nafion-based PEMFCs and therefore can be a significant candidate for cogeneration residential systems. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-Family Household. A complete fuel processing subsystem, with all necessary BOP (balance-of-plant) components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system is simulated in LabVIEW™ environment to provide the ability of Data Acquisition of actual components and thereby more realistic design in the future. A part-load study has been conducted to indicate performance characteristics at off-design conditions. The system is sized to provide realistic dimensioning of the actual system.
