Optimizing CO2 emissions from heating and cooling and from the materials used in residential buildings,depending on their geometric characteristics

The objective of this research was to obtain the environmentally optimal design of a building with the following starting conditions: constant constructed surface, constant volume, square floor layout, and a variable number of floors. For this purpose, the study evaluated the impact of CO₂ emissions stemming from the energy needed to maintain the building at a constant temperature of 19 °C in winter and 25 °C in the summer. Furthermore, one of the results was the CO₂ emissions curve from the manufacturing of the materials used in the construction of the building and the building envelope.     

European residential buildings and empirical assessment of the Hellenic building stock,energy consumption,emissions and potential energy savings

The existing building stock in European countries accounts for over 40% of final energy consumption in the European Union (EU) member states, of which residential use represents 63% of total energy consumption in the buildings sector. Consequently, an increase of building energy performance can constitute an important instrument in the efforts to alleviate the EU energy import dependency (currently at about 48%) and comply with the Kyoto Protocol to reduce carbon dioxide emissions. This is also in accordance to the European Directive (EPBD 2002/91/EC) on the energy performance of buildings, which is currently under consideration in all EU member states. This paper presents an overview of the EU residential building stock and focuses on the Hellenic buildings. It elaborates the methodology used to determine the priorities for energy conservation measures (ECMs) in Hellenic residential buildings to reduce the environmental impact from CO₂ emissions, through the implementation of a realistic and effective national action plan. A major obstacle that had to overcome was the need to make suitable assumptions for missing detailed primary data. Accordingly, a qualitative and quantitative assessment of scattered national data resulted to a realistic assessment of the existing residential building stock and energy consumption. This is the first time that this kind of aggregate data is presented on a national level. Different energy conservation scenarios and their impact on the reduction of CO₂ emissions were evaluated. Accordingly, the most effective ECMs are the insulation of external walls (33–60% energy savings), weather proofing of openings (16–21%), the installation of double-glazed windows (14–20%), the regular maintenance of central heating boilers (10–12%), and the installation of solar collectors for sanitary hot water production (50–80%).     

Iron type catalysts for the ozonation of oxalic acid in water

Two iron catalysts (Fe(III) and Fe2O3/Al2O3) have been used in the ozonation of oxalic acid in water at pH 2.5. Percentage removals of oxalic acid were 1.8%, 7% and 30% corresponding to the non-catalytic, homogeneous (Fe(III)) and heterogeneous (Fe2O3/Al2O3) catalytic ozonations, respectively. Catalytic oxalic acid ozonation leads in all cases to total mineralization. The mechanism of ozonation likely develops through formation of iron-oxalate complexes that further react with ozone without the participation of hydroxyl radicals. Because of the stringent acidic conditions, some metal leaching has been observed and quantified in the heterogeneous process. In the homogeneous catalysis, the kinetics was found to be first order with respect to ozone and oxalic acid while for the heterogeneous catalysis, the kinetic order depends on the concentration of ozone in the gas fed. Thus, at ozone concentrations lower than 30 mg L(-1), the heterogeneous ozonation is between first and zero order with respect to both ozone and oxalic acid while at higher ozone gas concentrations, the kinetics was found to be first and zero order with respect to oxalic acid and ozone, respectively. This kinetics is supported through an Eley-Rideal mechanism that involves a surface reaction between non-adsorbed ozone and adsorbed oxalic acid. Apparent activation energies of the homogeneous and heterogeneous catalytic ozonations were found to be 18.2 and 13.6 kcal mol(-1), respectively.     

Saturation, energy consumption, CO2 emission and energy efficiency from urban and rural households appliances in Mexico

Energy usage and energy efficiency are of increasing concern in Mexico, electricity generation principally depends upon fossil fuels. On one hand, the stocks of these fuels have been confirmed to be critically limited. On the other hand, in process of electricity generation by means of these fuels, a number of poisonous by-products adversely affect the conservation of natural eco-system.This paper focuses on estimation of energy consumption, energy savings, reduction of emissions of CO₂ for use of urban and rural household appliances in Mexico between 1996 and 2021.The analysis concentrates on six major energy end uses in the residential sector: refrigerators, air conditioners, washing machines, TV set, iron and heater.It is estimated that by 2021 there will be a cumulative saving of 22,605 GWh, as a result of the implementation of government programs on energy efficiency that represents a cumulative reduction of CO2 emissions of 15,087 Tg CO2.It means that Mexico can reduce in 5650 MW the generation capacity of national electricity system, which is to avoid burning 40.35 MM barrels of oil.The findings can be useful to policy makers as well as household appliances users.     

Analysis of domestic hot water energy consumption in large buildings under standard conditions in Senegal

This paper presents an investigation of the energy consumption due to domestic hot water (DHW) production in large buildings. We have studied three types of reference buildings: one office, one residence and a 3-star hotel located in Senegal. The DOE2.1E (the building energy program of the Department of Energy Version 2.1E) has been used. One of its main advantage is that it allows to take into account both energy end use categories and a great number of parameters of the building energy performance. Four climatic regions have been identified and their equivalent “standard” conditions are all defined. Those conditions are the same as the current design and operating conditions of each type of building. The DHW energy consumption is calculated and compared with the total energy generated by all end uses (lighting, cooling/ventilation, DHW, and other equipment). Before we carry out wide and systematic simulations of the three buildings energy performance, we pay special attention to check and validate the DHW part of the DOE2.1E model. There was an agreement between the recorded monthly DHW energy load on the one hand, and on the other the computed results. We end up finding results that could open new perspectives for building a strategic methodology to provide guidelines for DHW energy saving measures in large buildings in West Africa. Furthermore, it is expected that energy researchers concerned about energy and environmental efficiency would consider this study for promoting CO₂ emission reduction in relation with DHW production in large buildings.     

Heavy coal combustion as the dominant source of particulate pollution in Taiyuan, China, corroborated by high concentrations of arsenic and selenium in PM10

Coal burning generates toxic elements, some of which are characteristic of coal combustion such as arsenic and selenium, besides conventional coal combustion products. Airborne particulate samples with aerodynamic diameter less than 10 microm (PM(10)) were collected in Taiyuan, China, and multi-element analyses were performed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of arsenic and selenium from ambient air in Taiyuan (average 43 and 58 ng m(-3), respectively) were relatively high compared to what is reported elsewhere. Arsenic and selenium were found to be highly correlated (r=0.997), indicating an overwhelmingly dominant source. Correlation between these two chalcophile elements and the lithophile element Al is high (r is 0.75 and 0.72 for As and Se, respectively). This prompted the hypothesis that the particles were from coal combustion. The enrichment of the trace elements could be explained by the volatilization-condensation mechanism during coal combustion process. Even higher correlations of arsenic and selenium with PM(10) (r=0.90 and 0.88) give further support that airborne particulate pollution in Taiyuan is mainly a direct result of heavy coal consumption. This conclusion agrees with the results from our previous study of individual airborne particles in Taiyuan.     

Air pollution and meteorological processes in the growing dryland city of Urumqi (Xinjiang, China)

Seven years (2000-2006) of monthly PM₁₀ (particulate matter, d ≤ 10 μm), SO₂, and NO₂ concentrations are reported for Urumqi, the capital of Xinjiang in NW China. Considerably high mean annual concentrations have been observed, which ranged between 150 and 240 μg m^− 3 (PM₁₀), 31 and 50 μg m^− 3 (NO₂), and 49 and 160 μg m^− 3 (SO₂). The shapes of seasonal variation of all pollutants were remarkably similar; however, winter/summer ratios of concentrations were quite different for PM₁₀ (2-3) and NO₂ (≈ 4) compared to SO₂ (up to 30). Very high consumption rates of fossil fuels for energy generation and domestic heating are mainly responsible for high annual pollution levels, as well as the (very) high winter/summer ratios. Detailed analysis of the 2000-2006 records of Urumqi's meteorological data resulted in inter-annual and seasonal frequency distributions of (a) (surface) inversion events, (b) heights of surface inversions, (c) stability classes of Urumqi's boundary layer, and (d) the “Air Stagnation Index (ASI)”. Urumqi's boundary layer is shown to be characterized by high mean annual and seasonal frequencies of (surface) inversions and by the dominance of stable dispersion classes. A further outcome of the meteorological analysis is the proof of Urumqi's strong diurnal wind system, which might have particularly contributed to the stabilization of the nocturnal boundary layer. Annual and seasonal variations of pollutant's concentrations are discussed in the context of occurrences of inversions, boundary layer, stability classes, and ASI. The trend of Urumqi's air pollution indicates a strong increase of mean annual concentrations 2000-2003, followed by a slight increase during 2003-2006. These are in strong contrast to (a) the growth of Urumqi's fleet of motor vehicles and (b) to the growing number of stable regimes of Urumqi's boundary layer climate during same period. It is concluded that the (regional and) local administrative technical countermeasures have efficiently lowered Urumqi's air pollution levels.     

Energy use, CO2 emissions and waste throughout the life cycle of a sample of hotels in the Balearic Islands

Tourism is the most developed economic sector in the Balearic Islands. The great rise in construction activities within the last 50 years, the increase in energy use, in CO₂ emissions and in waste production due to tourism, as well as an electrical energy production system mainly based on coal and fossil fuels is not an environmentally sustainable scenario. The aim of this study is to identify the processes that have had the greatest impact on the life cycle of a tourist building. In order to do this, the energy uses, CO₂ emissions and waste materials generated have been estimated, assuming a life cycle of 50 years, within a sample of hotels from the Balearic Islands. The results show that the operating phase, which represents between 70% and 80% of the total energy use, is the one with the greatest impact; that the energy use due to the manufacture of materials represents a fifth of the total and that electric consumption is the main cause of CO₂ emissions because of the regional energy system.     

Analysis of energy and carbon flows in the future Norwegian dwelling stock

A dynamic analysis of future energy and carbon flows (2000–2050) is performed on the aggregated residential building stock in Norway. The basis for the analysis is a dynamic material flow analysis of floor areas and the main building materials. By adding energy intensity assumptions for space heating, water heating, domestic electrical appliances and embodied energy in construction materials, the future corresponding delivered energy demand is calculated. This forms the basis for life cycle estimation of the future direct and indirect greenhouse gas (GHG) emissions. The predicted demand for delivered energy in 2025 will increase by 24.0% and 12.5% above those for 2000 and 2010, respectively, and then remain stable towards 2050. Energy savings per unit of floor area are counterbalanced by growth in the building stock. The very high influence of energy technology assumptions within the electricity generation market is demonstrated, along with the large differences between using attributional and consequential life cycle assessment principles in the calculation of future emissions. Future electricity demand met by marginal power generation technologies in the European market will yield substantially higher GHG emissions. The simulations demonstrate the policy, strategy, and practical challenges in achieving significant long-term energy and GHG emission reductions from the residential building stock in a country with a rapidly growing population.

Une analyse dynamique des flux futurs d'énergie et de carbone (2000-2050) est réalisée en Norvège sur l'ensemble du parc de logements (immeubles résidentiels). La base de l'analyse consiste en une analyse dynamique des flux de matières des surfaces au sol et des principaux matériaux de construction. En ajoutant des hypothèses relatives à l'intensité énergétique concernant le chauffage d'ambiance, la production d'eau chaude, les appareils électroménagers et l'énergie intrinsèque des matériaux de construction, la demande future correspondante en énergie livrée est calculée. Ceci constitue la base pour l'estimation du cycle de vie des futures émissions directes et indirectes de gaz à effet de serre (GES). La demande prévue d'énergie livrée en 2025 sera en augmentation de 24,0% et de 12,5%, respectivement, par rapport à la demande de 2000 et à celle de 2010, puis demeurera stable vers 2050. Les économies d'énergie par unité de surface au sol sont contrebalancées par la croissance du parc bâti. Démonstration est faite de la très forte influence des hypothèses relatives aux technologies énergétiques dans le marché de la production d'électricité, ainsi que des grandes différences existant entre le fait d'utiliser, pour le calcul des émissions futures, les principes d'une analyse attributionnelle et ceux d'une analyse conséquentielle du cycle de vie. La demande future d'électricité satisfaite par les technologies marginales de production d'électricité dans le marché européen générera des émissions de gaz à effet de serre sensiblement plus élevées. Les simulations montrent les défis qui se posent en termes de politique, de stratégie et sur le plan pratique, pour réaliser des réductions à long terme importantes de la consommation énergétique et des émissions de GES provenant du parc bâti résidentiel.

secteur du bâtiment?parc bâti?bâtiments?réduction du CO₂?consommation énergétique?émissions de gaz à effet de serre?analyse des flux de matières?atténuation?Norvège     

Evaluation of a photocatalytic reactor membrane pilot system for the removal of pharmaceuticals and endocrine disrupting compounds from water

A photocatalytic reactor membrane pilot system, employing UV/TiO₂ photocatalysis, was evaluated for its ability to remove thirty-two pharmaceuticals, endocrine disrupting compounds, and estrogenic activity from water. Concentrations of all compounds decreased following treatment, and removal followed pseudo-first-order kinetics as a function of the amount of treatment. Twenty-nine of the targeted compounds in addition to total estrogenic activity were greater than 70% removed while only three compounds were less than 50% removed following the highest level of treatment (4.24 kW h/m³). No estrogenically active transformation products were formed during treatment. Additionally, the unit was operated in photolytic mode (UV only) and photolytic plus H₂O₂ mode (UV/H₂O₂) to determine the relative amount of energy required. Based on the electrical energy per order (EEO), the unit achieved the greatest efficiency when operated in photolytic plus H₂O₂ mode for the conditions tested.