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Undoubtedly energy is one of the most important factors in the sustainable development of human societies .the most important human based factor of destructing and polluting environment is production Transmission and consumption of various types of energy. Non-renewability, price rising and environmental impact of fossil fuels are important factors that indicated using of renewable energies. One of them is solar energy. The use of that in many countries faced to increasing growth. So many ways exist to use this clear energy, but using solar water heater maybe the easiest and most economical methods. So its necessary to study socio-economical and environmental benefits. The aim of this paper is to analyses socio-economical and environmental benefits of solar water heater usage along families of 4-5 members and estimate return period of this technologys initial investment in the city of Shiraz. The results show amount of saving energy, social costs, reducing emission of pollutants and reducing costs of CO2 elimination per a year, will respectively be 710494814 Kwh, 7128396225 Toman, 485,577 tons And 17481888324 Tomans. Also the return period of the initial investment of using solar water heater is about 3/23 years.

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In recent decades, greenhouse gas (GHG) emissions, particularly CO2, has led to catastrophic environmental impacts such as global warming. In addition to natural emissions, human activities are among the most important causes of CO2 emission. Meanwhile, energy consumption possesses the biggest share in CO2 emission. Various sectors, including industry, transportation and building, consume energy which each one has a significant role in air pollution and GHG emissions. According to official statistics, buildings own more than one third of the world energy consumption. Therefore, the role of huge buildings, as big energy systems would be very important. In this paper, a model for CO2 emission caused by energy consumption in a large building is provided and the emitted CO2 from a real building as a case study is then calculated.

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As regards carbon dioxide emissions are the major cause of climate change for numerous, study on the factors affecting its emissions have a high significance. This study focuses on the relationship between co₂ emissions and GDP, population growth, openness and energy consumption, which inclusive a wider range of factors affecting on co₂ emissions will be examined. For this purpose, long-term and short-term relationship between co₂ emissions and other variables is estimated and analyzed with utilizing ARDL model for annual data from 1972 to 2011.The results of this study indicate that all variables except for openness, have a positive impact on co₂ emissions, while openness has a negative effect on co₂ emissions.

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The activities of human civilization have imposed a high burden on the environment since the beginning of history on a global scale. That is why energy producers and consumers need to think deeply about the role that energy plays to achieve sustainable development. In this context, the maintenance of the environment, which cannot be replaced, should be taken into account precisely. Rising energy prices and market volatility, industry towards the use of energy management systems has led in order to compete reliable. Pulp and paper industry is not exception from this rule, Because the production of paper and paperboard demand is rising significantly on a global scale, that These factors lead to increased energy consumption and greenhouse gas emissions such as CO2 in this sector. In this context, a review of previous research and integrate them with the views of the experts, new methods for selecting the most appropriate technology in different sectors of the pulp and paper plant are provided.

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