One of the ways to decrease the global primary energy consumption and the corresponding greenhouse gas emissions is the application of the combined cooling, heating and power generation technologies, known as trigener...One of the ways to decrease the global primary energy consumption and the corresponding greenhouse gas emissions is the application of the combined cooling, heating and power generation technologies, known as trigeneration system. In this research an innovative trigeneration system, composed by an absorption heat pump, a mechanical compression heat pump, a steam plant, and a heat recovery plant is developed. The low tem- perature heat produced by absorption chiller is sent to a mechanical compression heat pump, that receives pro- cess water at low temperature from the heat recovery plant and bring it to higher temperatures. The trigeneration system is fed by biogas, a renewable energy. A design and a simulation of the system are developed by ChemCad 6.3 software. The plant produces 925 kW of electrical energy, 2523 kW of thermal energy and 473 kW of cooling energy, by the combustion of 3280 kW of biogas. Primary energy rate （P.E.R.） is equal 1.04 and a sensitivity analysis is carried out to evaluate the effect of cooling capacity, produced electrical energy and process water temperature. The first has a negative effect, while other parameters have a positive effect on P.E.R. Compared to a cogeneration system, the tdgeneration plant produces the 28% higher of power and the 40% lower of carbon dioxide emissions. An economic analysis shows that the plant is economically feasible only consid- ering economic incentives obtained by the use of heat pumps and steam plant at high efficiency. Saving 6431 t.a-1 corresponding to 658000 EUR.a-1 of incentives, the plant has a net present value （N.P.V.） and a pay back period （P.B.P.） respectively equal to 371000 EUR and 4 year. Future works should optimize the process considering cost and energetic efficiency as the two objective functions.展开更多
This study provides estimates of smallholder household＇s production efficiency and its determinants, and separately analyses the technical efficiency of dairy technology adopting and non-adopting farmers using data f...This study provides estimates of smallholder household＇s production efficiency and its determinants, and separately analyses the technical efficiency of dairy technology adopting and non-adopting farmers using data from Ethiopia. Cobb-Douglas stochastic frontier production function was modeled in the context of local level agricultural innovation systems framework and estimated using 2011 milk production data on 304 dairy farmers. Results show that the mean level of technical efficiency among the sampled farmers was about 26%. This result suggests that there is room for significant increases of production through reallocation of existing resources. Despite significant variation among farmers, these results also indicate only 19% of farmers have mean efficiency scores （_〉 50%）, implying a need to focus on creating innovation capacity that pushes the production frontier outward in the dairy production system. It is also revealed that individual farm households＇ efficiency varied widely across dairy technology adoption status, gender and districts. The significant gamma （g） statistic, of 0.9985 in the analysis indicates that about 99.85% variation in the output of milk production would be attributed to technical inefficiency effects （those under farmer＇s control） while only 0.0015% would be due to random effects, i.e., beyond the farmers control and hence calling for a focus on efficiency enhancing investments. Education, farm size, extension visit and off-farm income opportunity were found to be efficiency enhancing. The study recommends that different components of an agricultural innovation system have to interact to improve the innovation capacity of different actors and thereby improve the estimated technical inefficiencies.展开更多
Analyzed the monitor results under current systems concerning game and then pointed out that a way-out to improve chinese coal mine production safety control is to implement system innovation and punish the monitor＇s...Analyzed the monitor results under current systems concerning game and then pointed out that a way-out to improve chinese coal mine production safety control is to implement system innovation and punish the monitor＇s lazy behaviors strictly.展开更多
文摘One of the ways to decrease the global primary energy consumption and the corresponding greenhouse gas emissions is the application of the combined cooling, heating and power generation technologies, known as trigeneration system. In this research an innovative trigeneration system, composed by an absorption heat pump, a mechanical compression heat pump, a steam plant, and a heat recovery plant is developed. The low tem- perature heat produced by absorption chiller is sent to a mechanical compression heat pump, that receives pro- cess water at low temperature from the heat recovery plant and bring it to higher temperatures. The trigeneration system is fed by biogas, a renewable energy. A design and a simulation of the system are developed by ChemCad 6.3 software. The plant produces 925 kW of electrical energy, 2523 kW of thermal energy and 473 kW of cooling energy, by the combustion of 3280 kW of biogas. Primary energy rate （P.E.R.） is equal 1.04 and a sensitivity analysis is carried out to evaluate the effect of cooling capacity, produced electrical energy and process water temperature. The first has a negative effect, while other parameters have a positive effect on P.E.R. Compared to a cogeneration system, the tdgeneration plant produces the 28% higher of power and the 40% lower of carbon dioxide emissions. An economic analysis shows that the plant is economically feasible only consid- ering economic incentives obtained by the use of heat pumps and steam plant at high efficiency. Saving 6431 t.a-1 corresponding to 658000 EUR.a-1 of incentives, the plant has a net present value （N.P.V.） and a pay back period （P.B.P.） respectively equal to 371000 EUR and 4 year. Future works should optimize the process considering cost and energetic efficiency as the two objective functions.
文摘This study provides estimates of smallholder household＇s production efficiency and its determinants, and separately analyses the technical efficiency of dairy technology adopting and non-adopting farmers using data from Ethiopia. Cobb-Douglas stochastic frontier production function was modeled in the context of local level agricultural innovation systems framework and estimated using 2011 milk production data on 304 dairy farmers. Results show that the mean level of technical efficiency among the sampled farmers was about 26%. This result suggests that there is room for significant increases of production through reallocation of existing resources. Despite significant variation among farmers, these results also indicate only 19% of farmers have mean efficiency scores （_〉 50%）, implying a need to focus on creating innovation capacity that pushes the production frontier outward in the dairy production system. It is also revealed that individual farm households＇ efficiency varied widely across dairy technology adoption status, gender and districts. The significant gamma （g） statistic, of 0.9985 in the analysis indicates that about 99.85% variation in the output of milk production would be attributed to technical inefficiency effects （those under farmer＇s control） while only 0.0015% would be due to random effects, i.e., beyond the farmers control and hence calling for a focus on efficiency enhancing investments. Education, farm size, extension visit and off-farm income opportunity were found to be efficiency enhancing. The study recommends that different components of an agricultural innovation system have to interact to improve the innovation capacity of different actors and thereby improve the estimated technical inefficiencies.
文摘Analyzed the monitor results under current systems concerning game and then pointed out that a way-out to improve chinese coal mine production safety control is to implement system innovation and punish the monitor＇s lazy behaviors strictly.
