Single stage absorption chillers using H2O-NH3 have received increasing research interest in recent years,in order to make them competitive with conventional refrigeration machines.This work presents a study on the pe...Single stage absorption chillers using H2O-NH3 have received increasing research interest in recent years,in order to make them competitive with conventional refrigeration machines.This work presents a study on the performance of such tri-thermal machines,used for negative temperature refrigeration.The objective is to determine the values of the system operating temperatures that minimize the irreversible losses in the various heat exchangers.To do this,the overall exergy efficiency of the system has been expressed as a function of the various operating temperatures.This objective function is to be maximized with experimental design method.The normal probability plot of the residual indicates that the random errors for the process are drawn from approximately normal distributions.From the results,with exergy efficiency greater than 0.4,two operating modes are presented which can be with condensation temperatures below 32℃and above 38℃.展开更多
This work focuses on the development of local building materials in Benin for their efficient use in buildings. It aims to make mud bricks lightened with good mechanical, thermal and sound properties and enhance the w...This work focuses on the development of local building materials in Benin for their efficient use in buildings. It aims to make mud bricks lightened with good mechanical, thermal and sound properties and enhance the waste polystyrene. This article is the result of experimental work on a broad field of applied sciences： building mechanics. The study is focused on BTS （blocks of stabilized earth） chosen as reference materials to which we linked polystyrene. The percentage of polystyrene varies from 0% to 100% starting from a constant volume of each reference material. The results showed that the increase in polystyrene percentage lowers mechanical properties. These results also showed that the gradual addition of polystyrene to the laterite-cement mixture has a significant influence on the density and mechanical resistances of the final composite material.展开更多
文摘Single stage absorption chillers using H2O-NH3 have received increasing research interest in recent years,in order to make them competitive with conventional refrigeration machines.This work presents a study on the performance of such tri-thermal machines,used for negative temperature refrigeration.The objective is to determine the values of the system operating temperatures that minimize the irreversible losses in the various heat exchangers.To do this,the overall exergy efficiency of the system has been expressed as a function of the various operating temperatures.This objective function is to be maximized with experimental design method.The normal probability plot of the residual indicates that the random errors for the process are drawn from approximately normal distributions.From the results,with exergy efficiency greater than 0.4,two operating modes are presented which can be with condensation temperatures below 32℃and above 38℃.
文摘This work focuses on the development of local building materials in Benin for their efficient use in buildings. It aims to make mud bricks lightened with good mechanical, thermal and sound properties and enhance the waste polystyrene. This article is the result of experimental work on a broad field of applied sciences： building mechanics. The study is focused on BTS （blocks of stabilized earth） chosen as reference materials to which we linked polystyrene. The percentage of polystyrene varies from 0% to 100% starting from a constant volume of each reference material. The results showed that the increase in polystyrene percentage lowers mechanical properties. These results also showed that the gradual addition of polystyrene to the laterite-cement mixture has a significant influence on the density and mechanical resistances of the final composite material.
