More than 10% of the population in Salta is regarded as rural. Many rural areas suffer a shortage of energy, and consequently, possibilities of social and economic development of the inhabitants become reduced. The ac...More than 10% of the population in Salta is regarded as rural. Many rural areas suffer a shortage of energy, and consequently, possibilities of social and economic development of the inhabitants become reduced. The activation of renewable energy sources in these areas presents inhabitants the advantages to generate their own energy. Dispersed rural communities create small electricity demands that are not considered by suppliers, because they are not profitable. Although thus far, feasibility analyses to install photovoltaic or thermal solar collectors are based on technical reasons, it seems more convenient that, in the future, projects for the installation of technology based on renewable energy should consider social indicators. As a preliminary step to field work is proposed in this paper using an equation that allows us to obtain a value of＂social index＂. With this analysis and the current survey accompanied by the local people, knowledge will be obtained of the real needs of these rural communities. The results show that there is a variation that would allow a classification or ordering of localities. To validate the results obtained is proposed as the next step to perform field work in each of the localities.展开更多
Solar energy is the most available, clean and inexpensive source of energy among the other renewable sources of energy. This work deals with experimental steady to determent the performance of solar tower steam produc...Solar energy is the most available, clean and inexpensive source of energy among the other renewable sources of energy. This work deals with experimental steady to determent the performance of solar tower steam production for power generation. Designed and fabricated of a solar tower, consist of a central receiver tank （0.4 m × 0.6 m × 1.0 m） and 150 heliostat mirrors arranged around it. The central tank was made of galvanized steel. Each heliostat consisted of two （0.5 m × 0.5 m） mirrors. The results of this work produce steam at temperature 110 ℃. Large steam quantity could be obtained when using large scale experimental. The results of the work give good indication for application of solar energy to produce power in Iraq.展开更多
The entransy theory, which can be used to optimize the heat transfer network of a solar power tower system （SPTS） and im- prove its energy efficiency, was introduced in this paper. Firstly, the irreversibility of th...The entransy theory, which can be used to optimize the heat transfer network of a solar power tower system （SPTS） and im- prove its energy efficiency, was introduced in this paper. Firstly, the irreversibility of the heat transfer processes in a SPTS was analyzed and the total entransy dissipation equation of a SPTS was derived. Then, two types of optimization problems （reduc- ing the total circulating flow rate or the total heat-exchanging area） of a SPTS were solved with conditional extremum model based on the formulas of total entransy dissipation. Finally, the entransy dissipation-based optimization principle was applied to a simple SPTS without re-heater and a complex SPTS with a re-heater. The results showed that under the chosen calculation conditions the minimum total thermal conductance was 19306.03 W K-~ for a SPTS without re-heater when the total heat ca- pacity rate of heat transfer fluid （HTF） was 3200 W K-1. The minimum total thermal conductance was about 7.9% lower than the value predicted based on the typical outlet temperature of a receiver. This meant that the total heat exchange area or initial investment could be effectively reduced under the prescribed total HTF circulating flow rate. We also studied the variation trends of the two optimized results including minimum total HTF heat capacity rate and minimum total thermal conductance. The minimum total HTF heat capacity rate decreased with the given total thermal conductance, the minimum total thermal conductance decreased first and then increased with the given total HTF heat capacity rate. We also found that for a SPTS with a re-heater, the mixing temperature and the mixing position of HTF had significant effects on the two types of optimization problems.展开更多
文摘More than 10% of the population in Salta is regarded as rural. Many rural areas suffer a shortage of energy, and consequently, possibilities of social and economic development of the inhabitants become reduced. The activation of renewable energy sources in these areas presents inhabitants the advantages to generate their own energy. Dispersed rural communities create small electricity demands that are not considered by suppliers, because they are not profitable. Although thus far, feasibility analyses to install photovoltaic or thermal solar collectors are based on technical reasons, it seems more convenient that, in the future, projects for the installation of technology based on renewable energy should consider social indicators. As a preliminary step to field work is proposed in this paper using an equation that allows us to obtain a value of＂social index＂. With this analysis and the current survey accompanied by the local people, knowledge will be obtained of the real needs of these rural communities. The results show that there is a variation that would allow a classification or ordering of localities. To validate the results obtained is proposed as the next step to perform field work in each of the localities.
文摘Solar energy is the most available, clean and inexpensive source of energy among the other renewable sources of energy. This work deals with experimental steady to determent the performance of solar tower steam production for power generation. Designed and fabricated of a solar tower, consist of a central receiver tank （0.4 m × 0.6 m × 1.0 m） and 150 heliostat mirrors arranged around it. The central tank was made of galvanized steel. Each heliostat consisted of two （0.5 m × 0.5 m） mirrors. The results of this work produce steam at temperature 110 ℃. Large steam quantity could be obtained when using large scale experimental. The results of the work give good indication for application of solar energy to produce power in Iraq.
基金supported by the National Natural Science Foundation of China(Grant No.U1261112)the Research Project of Chinese Ministry of Education(Grant Nos.113055A,20120201130006)
文摘The entransy theory, which can be used to optimize the heat transfer network of a solar power tower system （SPTS） and im- prove its energy efficiency, was introduced in this paper. Firstly, the irreversibility of the heat transfer processes in a SPTS was analyzed and the total entransy dissipation equation of a SPTS was derived. Then, two types of optimization problems （reduc- ing the total circulating flow rate or the total heat-exchanging area） of a SPTS were solved with conditional extremum model based on the formulas of total entransy dissipation. Finally, the entransy dissipation-based optimization principle was applied to a simple SPTS without re-heater and a complex SPTS with a re-heater. The results showed that under the chosen calculation conditions the minimum total thermal conductance was 19306.03 W K-~ for a SPTS without re-heater when the total heat ca- pacity rate of heat transfer fluid （HTF） was 3200 W K-1. The minimum total thermal conductance was about 7.9% lower than the value predicted based on the typical outlet temperature of a receiver. This meant that the total heat exchange area or initial investment could be effectively reduced under the prescribed total HTF circulating flow rate. We also studied the variation trends of the two optimized results including minimum total HTF heat capacity rate and minimum total thermal conductance. The minimum total HTF heat capacity rate decreased with the given total thermal conductance, the minimum total thermal conductance decreased first and then increased with the given total HTF heat capacity rate. We also found that for a SPTS with a re-heater, the mixing temperature and the mixing position of HTF had significant effects on the two types of optimization problems.
