The usage of renewable energies,including geothermal energy,is expanding rapidly worldwide.The low efficiency of geothermal cycles has consistently highlighted the importance of recovering heat loss for these cycles.T...The usage of renewable energies,including geothermal energy,is expanding rapidly worldwide.The low efficiency of geothermal cycles has consistently highlighted the importance of recovering heat loss for these cycles.This paper proposes a combined power generation cycle(single flash geothermal cycle with trans-critical CO_(2) cycle)and simulates in the EES(Engineering Equation Solver)software.The results show that the design parameters of the proposed system are significantly improved compared to the BASIC single flash cycle.Then,the proposed approach is optimized using the genetic algorithm and the Nelder-Mead Simplex method.Separator pressure,steam turbine output pressure,and CO_(2) turbine inlet pressure are three assumed variable parameters,and exergy efficiency is the target parameter.In the default operating mode,the system exergy efficiency was 32%,increasing to 39%using the genetic algorithm and 37%using the Nelder-Mead method.展开更多
Using Lean Manufacturing(LM)tools in production processes is crucial for companies’economic,environmental,and social sustainability success.This study shows a structural equation model(SEM)that shows the relationship...Using Lean Manufacturing(LM)tools in production processes is crucial for companies’economic,environmental,and social sustainability success.This study shows a structural equation model(SEM)that shows the relationship between LM Tools like Kaizen(KAI),Gemba(GEM),Value Stream Mapping(VSM)and Key Performance Indicator(KPI)with Economic Sustainability(ECS).Seven hypotheses were evaluated with data from 179 responses to a questionnaire about the Mexican maquiladora industry,showing that these variables are linked.At a 95%confidence level,the model was evaluated using the partial least squares method.The findings indicate that the relationships between KAI and GEM and KAI and VSM have the strongest relationship,followed by VSM and ECS;however,VSM has the strongest effect on ECS.Based on these findings,it is recommended that managers adopt a continuous improvement(KAI)approach based on working directly on the shop floor(GEM and VSM)to support their decisions regarding economic growth(ECS).展开更多
基金Yashar Aryanfar is receiving a scholarship from the National Council of Science and Technology(CONACYT)of Mexico to pursue his doctoral studies at the Universidad Autonoma de Ciudad Juarez under Grant No.1162359.
文摘The usage of renewable energies,including geothermal energy,is expanding rapidly worldwide.The low efficiency of geothermal cycles has consistently highlighted the importance of recovering heat loss for these cycles.This paper proposes a combined power generation cycle(single flash geothermal cycle with trans-critical CO_(2) cycle)and simulates in the EES(Engineering Equation Solver)software.The results show that the design parameters of the proposed system are significantly improved compared to the BASIC single flash cycle.Then,the proposed approach is optimized using the genetic algorithm and the Nelder-Mead Simplex method.Separator pressure,steam turbine output pressure,and CO_(2) turbine inlet pressure are three assumed variable parameters,and exergy efficiency is the target parameter.In the default operating mode,the system exergy efficiency was 32%,increasing to 39%using the genetic algorithm and 37%using the Nelder-Mead method.
文摘Using Lean Manufacturing(LM)tools in production processes is crucial for companies’economic,environmental,and social sustainability success.This study shows a structural equation model(SEM)that shows the relationship between LM Tools like Kaizen(KAI),Gemba(GEM),Value Stream Mapping(VSM)and Key Performance Indicator(KPI)with Economic Sustainability(ECS).Seven hypotheses were evaluated with data from 179 responses to a questionnaire about the Mexican maquiladora industry,showing that these variables are linked.At a 95%confidence level,the model was evaluated using the partial least squares method.The findings indicate that the relationships between KAI and GEM and KAI and VSM have the strongest relationship,followed by VSM and ECS;however,VSM has the strongest effect on ECS.Based on these findings,it is recommended that managers adopt a continuous improvement(KAI)approach based on working directly on the shop floor(GEM and VSM)to support their decisions regarding economic growth(ECS).
