Search

It is represented in this paper that a methodology to model and quantify the impact of the three environmental factors, the ambient temperature, the incident irradiance and the wind speed, upon the performance of photovoltaic array operating under outdoor conditions. First, A simple correlation correlating operating temperature with the three environmental variables is validated for a range of wind speed studied, 2-8ms-1 , and for irradiance values between 200 and 1000Wm-2 . Root mean square error (RMSE) between modeled operating temperature and measured values is 1.19% and the mean bias error (MBE) is -0.09%. The environmental factors studied influence I-V curves, P-V curves, and maximumpower outputs of photovoltaic array. The cell-to-module-to-array mathematical model for photovoltaic panels is established in this paper and the method defined as segmented iteration is adopted to solve the I-V curve expression to relate model I-V curves. The model I-V curves and P-V curves are concluded to coincide well with measured data points. The RMSE between numerically calculated maximum-power outputs and experimentally measured ones is 0.2307%, while the MBE is 0.0183%. In addition, a multivariable non-linear regression equation is proposed to eliminate the difference between numerically calculated values and measured ones of maximum power outputs over the range of high ambient temperature and irradiance at noon and in the early afternoon. In conclusion, the proposed method is reasonably simple and accurate. [ABSTRACT FROM AUTHOR]

Hydropower is an important energy source in Malawi because it provides almost all of the country's electricity generation capacity. This paper has reviewed the impacts of environmental degradation and climate change on hydropower generation in Malawi. Energy scenario and other issues that contribute towards the current state of environment have been discussed. All of Malawi's hydropower stations are run-of-river schemes cascaded along the Shire River with an installed capacity of nearly 280 MW. The generation is impacted negatively by floods, siltation, droughts and aquatic weeds infestation. The way how these challenges are being exacerbated by the poor state of the environment, especially within the Shire River basin in particular is also discussed in the paper. Measures taken by the national electricity utility company on how to manage the impacts are discussed as well. The paper concludes that hydropower generation system in a highly environmental degraded area is difficult to manage both technically and economically. In the case of Malawi, diversifying to other energy sources of generating electricity is considered to be a viable option. Some mitigation measures concerning environment degradation and climate change challenges have been suggested in the paper. [ABSTRACT FROM AUTHOR]

Liquid biofuels have come up strongly as possible substitute to conventional fossils fuels and woodfuels apparently because of its perceived environmental benefit, sustainability and recent hikes in petroleum fuel prices. These have led most countries to include biofuels in their energy mix to mitigate climate change effect caused by petroleum fuels and also to ensure energy security. Ghana as a developing country has also identified the potential of biofuels in her energy mix by setting some targets in its Strategic National Energy Policy (SNEP). This paper analyses the implications of the policy as presented in SNEP. It also looks at programmes put in place to achieve the set objectives and the possible challenges that are likely to be faced in their implementation. The paper concludes by calling for strong governmental involvement in achieving the set objectives. [ABSTRACT FROM AUTHOR]

Climate is an important factor in logical formation of urban structures and their type of architecture. The present study looks at the relationship between the traditional buildings and sustainable development as well as the climatic conditions and construction patterns in Shiraz, Iran. The purpose of this research is to help promote energy efficient architectural design in Semi hot-arid climates by introducing the technics that the traditional architects used to design buildings in Shiraz. The climatic design solutions studied in a number of traditional buildings Belong to Qajar era in Shiraz. Result of this paper; show that considering the experience in traditional architecture of Shiraz, it is possible to create an environmental and sustainable architecture. [ABSTRACT FROM AUTHOR]

The increased demand for energy in China has generated concomitant increase of carbon emissions, which poses an unprecedented challenge to China's, and even global, sustainable development. In this paper, from the perspective of provincial carbon emissions, we analyze China's carbon emissions changes during 1997-2007 based on the index decomposition analysis method. We find that: (1) China's CO2 emissions from end-use energy consumption mainly originated from such major industrial provinces as Hebei, Jiangsu, Zhejiang, Shandong, Henan and Guangdong. (2) Economic growth and decline in energy intensity will have the greatest impact on CO2 emissions from end-use energy consumption. Economic growth is the key factor driving the increase of CO2 emissions. Change in energy intensity can more or less decrease CO2 emissions. In the future, China's carbon emissions mitigation policies should be developed to address these differences in provincial carbon emissions. [ABSTRACT FROM AUTHOR]

In every efficient solar still design, water temperature, vapor temperature and distillate output, and difference between water temperature and inner glass cover temperatures are very important. Here, two dimensional three phase model of hemispherical solar still is made for evaporation as well as condensation process in ANSYS CFD. Simulation results like water temperature, vapor temperature, distillate output compared with actual experimental results of climate conditions of Mehsana (latitude of 23° 59' and longitude of 72° 38) of hemispherical solar still. Water temperature and distillate output were good agreement with actual experimental results. Study shows that ANSYS-CFD is very powerful as well as efficient tool for design, comparison purpose of hemispherical solar still. [ABSTRACT FROM AUTHOR]

Air pollution in developing countries has recently become a serious environmental problem, which needs more active air quality monitoring and analyses. To assess air quality characteristics over the city of Baghdad. temporal variations in CO, NO, NO2, NOX, O3, SO2 and PM10 Concentrations measured between May-December 2010 (245 days), at period from 8:00-16:00 daily hour from location called ALJadriyah station (44.1E -33.3N, 38.5m above sea level). From diurnal variability of these concentration, we see high daily values of CO and CH4 3.25, 1.9 PPM at November while NOX record 0.23 PPM at December that consider as highest daily value. While other pollutant concentration don't have large variation have 0.14-0.18 PPM. Particular matter at 10um (PM10) have 1.6g/m3 at 21/7/2010. At winter season and specifically at December month, there is good relation between the hourly concentration of PM10 and other chemical pollutant concentration such as CO,SO2, NO, NOX this can be putting by correlation coefficient r =0.7-0.5. The monthly mean concentration of pollutant CO, NOX, CH4, NO, NO2 recorded high value at August Month. While O3 have large mean concentration in November, while PM10 have large monthly mean concentration at June and July months where there is most frequent dust-storm events. High concentration and its frequency distribution shifts towards large values concentrated at summer seasons June, July, Aug. about 0.25-1.25 PPM and have frequency percent about 82.6%. In winter the frequency distribution shifts towards large values of O3 even above 61.2% in range 0.085- 0.105 PPM. Regarding the frequency distribution of SO2 all season where shifts towards lower except spring (May) 88.2% at range concentration 0.025-0.125 PPM. Nitrate oxide have different concentration an frequency at several season but NOX have large frequency at summer, other pollutant concentration CH4 and PM10 have high concentration frequency at this period. [ABSTRACT FROM AUTHOR]

Climate change is affecting human indoor thermal comfort. Human habitat roof's thermal insulation capacity may play key role in reducing the discomfort resulting from climate change. In the present study, six roof materials are analyzed for their thermal insulation capacity: aluminum-iron (Al-Fe) sheet, Al-Fe sheet with outer face white painted, Al-Fe sheet with various straw thick, white tile, red tile and gray tile. Solar radiations, ambient temperature, wind speed, roof inner and indoor temperatures were daily measured during April and June. Measured roof inner wall temperatures for each type of material agreed with the model set forth. The indoor temperature showed, under the same atmospheric conditions, Al-Fe sheet at a maximum of 51.4°C ; Al-Fe sheet with outer face white paint at 40.3°C; Al-Fe sheet with 3cm thick of straw at 41.2°C; and Al-Fe with 6cm thick of straw at 36.8°C, making the latter the better roof at day time. For the inner wall temperatures of the roof without ceilings, Al-Fe sheet has a maximum at 73°C; Al-Fe sheet with outer wall white paint at 48.1°C; Al-Fe sheet with 3cm straw thick at 45.2°C; and Al-Fe with 6cm straw thick at 37.9°C, red tile at 51.3°C; white tile at 41.6°C and grey tile at 51.6°C. This study enlightens the change that can be made on the traditional roof to improve indoor thermal comfort in changing climate conditions. [ABSTRACT FROM AUTHOR]

In steady-state methods for estimating energy consumption of buildings, the commonly used data include the monthly average dry bulb temperatures, the heating and cooling degree-days and the dry bulb temperature bin data. This work presents average values of these data for the 1983-1992 and 1993-2002 decades, calculated for Athens and Thessaloniki, determined from hourly dry bulb temperature records of meteorological stations (National Observatory of Athens and Aristotle University of Thessaloniki). The results show that the monthly average dry bulb temperatures and the annual average cooling degree-days of the 1993-2002 decade are increased, compared to those of the 1983-1992 decade, while the corresponding annual average heating degree-days are reduced. Also, the low temperature bins frequency results decreased in the 1993-2002 decade while the high temperature ones increased, compared to the 1983-1992 decade. The effect of temperature data variations on the energy consumption and on CO2 emissions of buildings was examined by calculating the energy demands for heating and cooling and the CO2 emissions from diesel-oil and electricity use of a typical residential building-model. From the study it is concluded that the heating energy requirements during the decade 1993-2002 were decreased, as compared to the energy demands of the decade 1983-1992, while the cooling energy requirements were increased. The variations of CO2 emissions from diesel oil and electricity use were analog to the energy requirements alterations. The results indicate a warming trend, at least for the two regions examined, which affect the estimation of heating and cooling demands of buildings. It, therefore, seems obvious that periodic adaptation of the temperature data used for building energy studies is required. [ABSTRACT FROM AUTHOR]

Fossil fuel which is the global energy source gives rise to land contamination, air pollution, climate change, fuel crises, hike of price of petroleum products, crises in oil producing nations, dependency on oil producing countries and high risk associated with oil exploitation has led to a search for sustainable and efficient energy sources. Several types and sources of biofuels have been recently studied as potential source of energy to replace the environmentally unfriendly fossil fuels. Bioethanol produced from terrestrial plants have attracted the attention of the global society, though numerous controversies and debates were associated with the technology; such as the issue of food versus fuel competition, which further encouraged more research work on a sustainable renewable bioethanol source. This study aims at determining total carbohydrates from macroalgal specie (Laminaria digitata) for use in bioethanol fermentation, also using wet and analytical chemistry to extract and spectrophotometrically analyse the sample in respect to glucose and sucrose standards. The samples were lyophilized and the resulting powder extracted in a water bath at 100°C in 15minutes. The analysis was performed using anthrone (colorimetric) method and the analyte read in a UV-visible spectrophotometer at 620nm. The result showed that carbohydrates were present in the samples, indicated by green and yellow, colourless pigments. Glucose and sucrose were the main identified sugars from the standards analysed. The concentration of sugars varied with time; months and seasons of the year. Result of the samples showed highest level of sugar concentration in May 2010 and lowest sugar concentration in November 2010. It was observed that the mass of sugars (glucose and sucrose) deposited as a result of photosynthesis, significantly contributed to the weight of biomass. The implication of the result indicated that: the smaller the biomass, the most likely it is to have lower mass of sugars and hence the less likely the potentials of synthesizing bioethanol from the sample. Conversely, a larger biomass signified the presence of more sugars, hence the greater the potentials for synthesis of bioethanol from the sample with larger biomass. [ABSTRACT FROM AUTHOR]