Energy and environmental analysis of glass container production and recycling

This work aims at examining, from an energy and environmental standpoint, one production cycle which is extremely energy-consuming, namely the glass production for drink containers. More specifically, the industrial process is first analysed as is, so as to evaluate and assess its energy needs and its associated environmental impact. As a second step the influence of glass container recycle and reuse on energy consumption and pollutant emission is investigated. To this end the recycling chain operation is illustrated and appropriate working hypotheses for the modified process are formulated, so that its energy and environmental performance can be evaluated. Finally, the two production scenarios are compared by means of LCA (Life Cycle Assessment) methodology, to the purpose of determining the best recycling percentage for glass containers from the standpoint of energy consumption and pollutant emission minimization, taking also into account the waste legislation currently in force.     

Energy savings of office buildings by the use of semi-transparent solar cells for windows

The study investigated a PV window that consists of a double glazed window with semi-transparent solar cells. The window provides natural light transmission as well as electricity production. The effect of the PV window on energy consumption of office buildings was analyzed in terms of heating and cooling loads, daylighting, and electricity production. The purposes of the study were to find the optimum solar cell transmittance and window to wall ratio (WWR), and to estimate energy savings of the building. A standard floor of an office building was modeled to run computer simulation, and annual energy simulation was performed with EnergyPlus. The results showed that the solar cell transmittance of 40% and WWR of 50% achieved the minimum electricity consumption in the building when artificial lighting was controlled with daylighting. The optimum solar cell transmittance for PV windows in different orientation was also presented. By using the optimum PV window, the electricity consumption was reduced by 55% compared to the single glazed window with WWR of 30% and no lighting control.     

Energy performance of glazings and windows

The purpose of the work is to make it possible to compare the energy performance of different glazings or windows in an easy way. The energy performance is expressed by the net energy gain, which is given as the solar gain minus the heat loss. The net energy gain from glazings and windows both depend on the thermal transmittance (the U-value) and the total solar energy transmittance (the g-value). This fact makes it difficult to choose the glazings or windows with respect to energy performance in a given case. To compare different glazings or windows in an easy way, diagrams have been produced which give the net energy gain based on the orientation, the tilt, the U-value and the g-value of the glazings or windows. In addition, a single diagram showing the net energy gain in a one-family house has been produced which takes into account the orientation of the windows in the building. This makes it possible to evaluate the energy performance of different glazings or windows for a one-family house using a single diagram. The diagrams give an easy way of comparing different glazings or windows so the best solution in a given case can be chosen. In addition, the diagram showing the net energy gain in a one-family house is used in the Danish Energy Labelling and Rating system for classification of glazings.     

Energy use efficiency in greenhouse tomato production in Iran

Efficient use of energy in agriculture is one of the conditions for sustainable production. In the present study energy use pattern for tomato production in Iran was investigated and a non-parametric data envelopment analysis (DEA) technique was applied to analyze the technical and scale efficiencies of farmers with respect to energy use for crop production. The energy use pattern indicated that diesel, electricity and chemical fertilizers are the major energy consuming inputs for tomato production in the region. Moreover, the results of DEA application revealed that of the average pure technical, technical and scale efficiencies of farmers were 0.94, 0.82 and 0.86, respectively. Also the results revealed that by adopting the recommendations based on the present study, on an average, about 25.15% of the total input energy could be saved without reducing the tomato yield.     

Energy and environmental life-cycle analysis of advanced windows

The environmental consequences of options for the manufacture, application, disposal, reuse and recycling, applicable to the full range of currently conceived advanced window systems, are discussed. Advanced window systems may incorporate, singly and in various combinations: evacuated contiguously-sealed glazing, electrochromics, thermochromics, photochromics, aerogels, xerogels, inert gas filled double glazings, low infra-red emittance coatings, diffractive daylight deflectors, holographic daylight deflectors refractive daylight deflectors, toughened glass.The primary impetus for the development of such systems is that their use enables buildings to incur minimal energy use by reducing window heat losses and/or the displacement of electric lighting by enhanced daylighting. The energy savings associated with advanced glazings displace the combustion of fossil fuels directly and indirectly; environmental benefits thus ensue. However these benefits may be offset by the impact of energy embodied from manufacture and the negative impacts of the extraction and disposal of constituent materials. Over their total life-cycle the environmental impact for advanced glazing systems and their associated means of manufacture, system fabrication and the tenable reuse, recycling and disposal options are unknown. The usefulness of life cycle analyses during the research and development stage is discussed.     

一种中空玻璃光伏组件的性能研究

研究了中空玻璃光伏组件的传热机理及在广州气候环境条件下的温度分布和发电性能。通过对一组中空玻璃光伏组件的长期监测,得到了该中空式光伏组件电性能与温度和辐照强度之间的关系,最后分析总结了中空光伏组件在使用过程中自爆的各种可能原因,并提出几点防范措施。     

Energy use and carbon dioxide emissions from steel production in China

In 1996, China manufactured just over 100 Mt of steel and became the world's largest steel producer. Official Chinese energy consumption statistics for the steel industry include activities not directly associated with the production of steel, ‘double-count’ some coal-based energy consumption, and do not cover the entire Chinese steelmaking industry. In this paper, we make adjustements to the reported statistical data in order to provide energy use values for steel production in China that are comparable to statistics used internationally. We find that for 1996, official statistics need to be reduced by 1365 PJ to account for non-steel production activities and double-counting. Official statistics also need to be increased by 415 PJ in order to include steelmaking energy use of small plants not included in official statistics. This leads to an overall reduction of 950 PJ for steelmaking in China in 1996. Thus, the official final energy use value of 4018 PJ drops to 3067 PJ. In primary energy terms, the official primary energy use value of 4555 PJ is reduced to 3582 PJ when these adjustments are made.     

温湿度对冰箱保温材料隔热性能影响研究

在不同工况下对冰箱保温材料聚氨酯发泡材料的导热系数及热工性能进行测试,结果表明:环境温湿度对冰箱保温材料的热工性能影响明显,保温材料的导热系数随温湿度的增大而增加;夏季高温工况时,保温材料隔热性能衰减4.11%;高低温交替变化条件下,保温材料隔热性能衰减为11.92%。研究结果可为今后冰箱隔热材料的制作过程提供理论指导,以达到降低能耗目的。     

Energy and greenhouse gas balance of the use of forest residues for bioenergy production in the UK

Life cycle analysis is used to assess the energy requirements and greenhouse gas (GHG) emissions associated with extracting UK forest harvesting residues for use as a biomass resource. Three forest harvesting residues were examined (whole tree thinnings, roundwood and brash bales), and each have their own energy and emission profile. The whole forest rotation was examined, including original site establishment, forest road construction, biomass harvesting during thinning and final clear-fell events, chipping and transportation. Generally, higher yielding sites give lower GHG emissions per ‘oven dried tonne’ (ODT) forest residues, but GHG emissions ‘per hectare’ are higher as more biomass is extracted. Greater quantities of biomass, however, ultimately mean greater displacement of conventional fuels and therefore greater potential for GHG emission mitigation. Although forest road construction and site establishment are “one off” events they are highly energy-intensive operations associated with high diesel fuel consumption, when placed in context with the full forest rotation, however, their relative contributions to the overall energy requirements and GHG emissions are small. The lower bulk density of wood chips means that transportation energy requirements and GHG emissions are higher compared with roundwood logs and brash bales, suggesting that chipping should occur near the end-user of application.     

Energy use patterns and econometric models of grape production in Hamadan province of Iran

This paper examines the energy use patterns and relationship between energy input and yield for grape production in Malayer region of Hamadan Province. Data from 50 farmers were collected using a face-to-face questionnaire method. In the surveyed vineyards, average yield and energy consumption were calculated as 18,530 kgha⁻¹ and 45,213.66 MJha⁻¹, respectively. Among input energy sources, fertilizers, electricity and farmyard manure contained highest energy shares with 37.25%, 19%, and 17.84%, respectively. The energy ratio and energy productivity were found to be 4.95 and 0.42 kgMJ⁻¹.Three econometric models were developed to estimate the impact of energy inputs on yield. The results revealed that impact of chemical, fertilizer and water on yield were significant at 1% probability level. Also, indirect and non-renewable energies were found to be rather high. Sensitivity analysis indicated that among the inputs, chemical has the highest MPP value of energy inputs. RTS (returns to scale) values for grape yield was found to be 2.15; thus, there prevailed an IRS of grape for estimated model. The net return was found to be positive as 2810.56 $ha⁻¹ for grape. The benefit-cost ratio was calculated as 2.08.     

Energy use and economical analysis of sugar beet production in Tokat province of Turkey

The purposes of this study were to determine energy consumption of input and output used in sugar beet production, and to make a cost analysis in Tokat, Turkey. Data were collected from 146 sugar beet farms in Tokat, Turkey by using a face-to-face questionnaire performed in January and February 2005. Farms were selected based on random sampling method. The results revealed that total energy consumption in sugar beet production was 39 685.51 MJ ha⁻¹, and accounted for 49.33% of fertilizer energy, and 24.16% of diesel energy. The output/input energy ratio was 25.75 and energy productivity was 1.53 kg MJ ha⁻¹. Results further indicated that 82.43% of total energy input was in non-renewable energy form, and only 12.82% was in renewable form. Economic analyses showed that profit–cost ratio of farms was 1.17. The highest energy cost items were labor, land renting, depreciation and fertilizers. Although intensive energy consumption in sugar beet production increased the yield, it also resulted in problems such as global warming, land degradation, nutrient loading and pesticide pollution. Therefore, there is a need to pursue a new policy to force producers to undertake energy-efficient practices to establish sustainable production systems without disrupting the natural resources. In addition, extension activities are needed to improve the efficiency of energy consumption and to sustain the natural resources.     

Energy use and efficiencies in the Arab countries

Energy data for Saudi Arabia, Libya, Tunisia, Sudan, and Yemen are selected to study energy efficiency in the Arab countries. Energy consumption in five sectors (namely, power generation, industry, transportation, agriculture, and the residential and commercial sectors) is analysed for these countries and compared with that in the remaining Arab countries. Energy flow charts are constructed and energy efficiencies determined. Finally, selected energy-conservation measures are highlighted for the specified sectors.     

Energy use pattern and sensitivity analysis of energy inputs and input costs for pear production in Iran

The purposes of this study were to determine energy use pattern and investigate the relationships between energy inputs and yield, cost inputs and income for pear production in the Tehran province of Iran. In this study, data were collected by administering a questionnaire in face-to-face interviews in the production year of 2009/2010. This article presents a comprehensive picture of the current status of energy consumption and some energy indices like energy ratio, energy productivity, specific energy, net energy and energy intensiveness. Results showed that the total energy input of 172,608.43 MJ ha⁻¹ was required for pear production. Among input energy sources, electricity energy with share of 78% of total input energy had the highest share. The energy use efficiency and energy productivity were found as 0.51 and 0.27 kg MJ⁻¹, respectively. To investigate the relationships between energy inputs and yield, cost inputs and income, Cobb–Douglas production function was selected as the best function. Sensitivity analysis of energy and cost inputs was carried out using the marginal physical productivity (MPP) technique. Economic analysis of pear production was carried out and total cost of pear production was obtained as 11,936.97 $ h⁻¹. Also the benefit to cost ratio was calculated as 3.11.     

Energy crop production costs in the EU

The objective of this study was to calculate indicative ranges of production costs and assess the main sources of cost for a number of energy crops, both annual and perennial, on a regional level in Europe. The production costs were calculated in terms of the economic compensation required by the farmer in order to grow the crop, and therefore include not only the cost of cultivation, but also the costs of land and risk, which are often omitted in production cost calculations. The cost of land was calculated as the opportunity cost based on the production of cereals. Thus, higher food prices lead to higher land costs, which in turn lead to higher energy crop production costs. The analysis was performed for three cases with different assumptions concerning yields and production cost reductions resulting from scale (total cultivation area in the region), and learning effects. The calculated energy crop production costs were found to be consistently lowest for short-rotation coppice (SRC) crops and highest for annual straw crops. The production costs of SRC crops were calculated to be about 4–5 € GJ⁻¹ under present conditions and 3–4 € GJ⁻¹ under improved future conditions. The production costs for perennial grasses were calculated to be about 6–7 € GJ⁻¹ and 5–6 € GJ⁻¹ under present and improved future conditions, respectively. The production costs for annual straw crops were estimated to be 6–8 € GJ⁻¹ under present conditions with small potential for cost reductions in the future.     

耐火材料节能化研究

针对耐火材料行业存在的高能耗问题,介绍了在节能降耗方面所做的一些工作.节能不仅要从耐火材料组织结构入手,通过降低材料热导率减少散热损失,还要考虑工业用窑炉的技术改进和废气余热利用、材料制备过程中工艺条件的选择与新工艺新技术的开发应用、废旧耐火材料的再资源化等方面,同时利用系统统筹方法,通过优化管理和参数匹配,并辅以微机管理技术对耐火材料生产过程实行最佳配置,以达到最大程度节约能量,保护环境的目的.     

Saving energy in residential buildings: The use of fully reversible windows

New double-glazed window systems based on the possibility of reversing the window through its sash could be in a short time a reality.     

Energy utilization in maize production

Average physical inputs in maize cultivation in three districts of Haryana (North India) have been transformed into energy units and compared with the energy outputs of grain and byproducts. The chief inputs were in the form of farm yard manure (FYM), traditional farm equipment, tractor and fuel, followed by irrigation and chemical fertilizers. Detailed data of physical inputs were collected from 31 individual farm units of Ambala district, ranging from 0.41 to 3.24 ha. Six of these farms showed extremes of size, tractor use, fertilizer application, FYM inputs, irrigation, as well as yields of grain and byproducts. Data from these farms were analysed in terms of energy utilization. Energy use efficiency ranged from 0.06 to 0.28 for grain and from 0.29 to 1.16 for total produce. The data suggest that grain production can be increased and energy utilization improved by minimizing the use of FYM and by increased use of chemical fertilizers and irrigation.     

Energy substitution in cotton production in the USA

The paper investigates the nature and extent of the substitution of energy for other inputs in the production of cotton in the USA. The specific inputs considered, in addition to energy, are labour, nitrogen fertilizer, phosphate fertilizer, pesticides and water. The results show that input use is responsive to variations in own prices and that some limited substitution does occur between energy, labour and nitrogen fertilizer.