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More than 20 billion tons of carbon is emitted as a result of the burning of fossil fuels. Half of this is absorbed by the ocean and vegetation and the other half remains in the atmosphere. The impact of this on natural ecosystems and humans is detrimental. Moreover, as demand increases and fossil fuels deplete, supplies approach disruption.
Modern architecture and engineering is continuously advancing to provide high levels of convenience and comfort. Up to 40% of global basic resources are taken up by the building sector. At the same time, the building sector is one of the largest consumers of fossil energy, after agriculture and industry.
A project called Asia-link, initiated by the European Commission, aims to raise awareness about building in a sustainable manner with nearly zero energy approach. This involves a combination of renewable energy technology and the building and engineering of applications such as heating/cooling systems and electricity production.
Sustainability is promoted in terms of how buildings are designed and constructed, thus improving the quality of building and their impact on the environment. Green buildings reduce operating costs, increase occupant productivity and increase building marketability.
The aim of sustainable design and building is to reduce the depletion of natural energy resources, prevent environmental degradation caused by the infrastructure and create safe built environments. There is enormous potential for energy reduction in buildings. From the year 2020, all buildings in the European Union will include all aspects that are needed to reach a nearly zero-energy construction. These aspects are related to the following:
- The use of solar power, passive heating and cooling designs and rain water harvesting
- Utility of low energy building materials
- Operational energy conservation
- The use of integrated renewable systems
Renewable Energy in Buildings
Renewable energy is energy derived from natural resources and is inexhaustible. These sources are called sustainable because of their minimal impact on the environment compared to fossil fuels. There are various ways to reduce energy consumption in buildings, thereby mitigating carbon emissions.
Buildings can be planned and constructed in a way to harness solar energy. Passive solar buildings use the free energy provided by the Sun for heating, cooling and daylight. Utilizing solar energy aids the reduction of energy consumption from other sources. Solar designs are compatible with any architectural style and can be implemented in existing buildings.
A considerable amount of heat and electricity used in buildings can be covered by solar energy via the use of solar thermal collectors. In recent years, other renewable sources of energy have come into practice. Wind turbines, biomass and hydrogen application has decreased the usage of conventional energy resources. Renewable sources of energy are almost equally distributed around the world and most importantly are inexhaustible. Other benefits of renewable energy technologies include the long lifetime of energy systems, increased employment and security of the energy supply.
Another recent advancement in the building sector is the integration of solar and wind power. There are various systems developed that can harness both solar and wind energy. The Hybrid photovoltaic-wind system has offered great opportunities for the production of energy based on solar and wind power. In places like Greece, which offers good sunshine and wind conditions, the combined use of photovoltaic and wind power has proven a great way to produce energy 24h a day. These types of systems are suitable for remote and rural areas where electricity is scarce. Another advantage of these hybrid systems is that solar power can be used during the day for energy production whereas wind power can be harnessed during the night, providing a full day renewable energy supply to buildings.
Another aspect related to the sustainability of buildings is the use of low energy building materials, i.e. low embodied energy of materials. This is the energy associated with all the processes involved in the construction of a building. Low embodied energy analysis, considering five types of building blocks (viz. stone, burnt clay brick, soil-cement, hollow concrete block and steam cured mud block), showed that soil-cement blocks are the most energy efficient material. The highest energy cost is associated with materials such as aluminum, copper, plastics and stainless steel. The total embodied energy of a building can be reduced by utilizing low embodied energy building materials.
Modern architecture poses a problem for sustainable energy usage by being extensively energy consumptive. However, technological advancements have made it possible to make use of nature's renewable and inexhaustible resources in the production of energy. Buildings are becoming more sustainable with time, harnessing solar, wind and hydrogen power. Buildings are making use of new heat-insulating techniques and in doing so are reducing the energy consumption and the environmental impact that they pose. The reduction of energy consumption ultimately leads to the reduction of carbon dioxide emissions aiding sustainable development.