Eco-architecture or Sustainable architecture is architecture that seeks to minimize the negative environmental impact of buildings by efficiency and moderation in the use of materials, energy, and development space and the ecosystem at large. Sustainable architecture uses a conscious approach to energy and ecological conservation in the design of the built environment.
The idea of sustainability, or ecological design, is to ensure that our actions and decisions today do not inhibit the opportunities of future generations.
The genesis of the term and its meaning
Sustainable building refers to an economic and ecological differentiation of the term hitherto understood in Germany under the name of ecological construction . The idea of sustainability already arose in the 18th century in forestry and was coined by the mining captain Hans Carl von Carlowitz . He recognized a connection between the wood scarcity resulting from massive deforestation and negative ecological and social conditions. As a result of his observations, he called for a careful handling of the resource wood, by which he understood the balanced relationship between cultivation and clearing of the wood . This thinking had implications until the 20th and 21st centuries. The Brundlandt Commission , founded by the United Nations in 1987, formulated the vision of sustainable development. This concept was to initiate a process of change that responds to negative changes in nature and climate and in the energy and resource budget with the demand for intergenerational equity. This propagates an economic approach that includes not only economic profit, but also environmental compatibility and social responsibility, and that the needs of today’s generations are agreed upon. The guiding principle of sustainability is based on the realization that economy, ecology and society are interdependent systems. The actors from the economy and society are increasingly recognizing that without the balance of the systems, the natural habitat is endangered and can no longer be secured for follow-on generations. The goals of sustainable building are also based on this idea.
A sustainable building is characterized by its high ecological, economic and socio-cultural quality. These three aspects form the three main pillars of sustainability. The criteria characterizing them are not isolated, but considered in an overall context. Starting point and important prerequisite for being able to make objective statements about the sustainable quality of a building is the consideration of the entire life span of a building. The life span of a building includes the phases of planning, construction, use, operation and demolition or dismantling. These different phases of a building together represent its life cycle. The life cycle thus forms the timeframe for assessing sustainability. All phases of the life cycle must be considered when assessing the sustainability of a building.
The proof of the sustainable quality of a building is usually provided by means of a building certification. In Germany, the following certification and evaluation systems have prevailed:
German Sustainable Building Council (DGNB),
Sustainable Building Assessment System for Federal Buildings (BNB),
Quality Seal Sustainable Housing (NaWoh),
Leadership in Energy and Environmental Design (LEED) and
Building Research Establishment Environmental Assessment Method (BREEAM).
Ecological quality: goals, criteria and measures
Ecology is one of the three main pillars of sustainability. It covers the aspects of resource conservation, protection of the global and local environment and the reduction of the total energy demand of the building. The consideration of these factors is of great importance due to climate change, rising energy prices and dwindling resource reserves. The following ecological criteria significantly determine the sustainable quality of a building.
Ensuring the longest possible life of a building as an important goal of sustainable construction includes the possibility of reuse of buildings. The use of buildings has the consequence that land use is reduced by new buildings. A reduction is necessary, because with the increasing development of areas the loss of the natural habitat for the resident flora and fauna and thus the extinction of species is associated. It also causes an increase in traffic, which in turn results in noise, emissions and high energy consumption. Similarly, the sealing of surfaces associated with the expansion significantly affects the natural water balance by disrupting the recharge of the groundwater and increasing the risk of flooding . On the other hand, soil and natural areas are spared due to the area-friendly control of settlement development . One example of an efficient measure to reduce reclamation is land recycling , which recycles waste land such as unused industrial and commercial sites or military sites.
A sustainable building is built on durability. The requirement for durability is taken into account above all in the preliminary planning and mainly concerns the building construction and the building materials . The longest possible service life can be ensured by the fact that multiple use is possible and the buildings can be adapted without changing the construction costs to a different type of use. Compared to the new construction, the conversion of the stock often turns out to be ecologically more advantageous, as it can reduce harmful environmental effects. Because usually – this can be determined in the context of a life cycle assessment and the life cycle cost calculation – when using existing buildings ( inventory use ) significantly lower energy and material flows in the field of building materials used as in the new building. Particularly high flexibility is offered by a modular design and the use of prefabricated components.
Building form and building orientation
The shape of the building and the orientation of the building are also important criteria for the sustainability of a building. Both factors contribute significantly to the energy efficiency of the building. A compact design is an essential prerequisite for a low heating demand. The more compact a building is, the lower the energy requirement, since in this case the ratio of heat-emitting surfaces, ie. H. the building envelope, the heated building volume is relatively low. This prevents heat loss. An energy-efficient construction also contributes to a high component mass in the interior, which serves as a thermal storage mass, by ensuring sufficient heat storage in winter and good cold storage in the summer. Determining factors for the heat demand of a building are also its orientation and the orientation of the windows. In the main orientation, the largest windows of the building are located in the south, in order to use the natural solar energy optimally passive. Excessive heat input due to solar radiation is prevented by appropriate shading systems (summer heat insulation). The roof is also oriented to the south, whereby the possibility of using a solar system is optimally ensured.
Sustainable buildings are characterized by ecologically sustainable optimization in the areas of resources, energy, water and wastewater. It essentially means reducing the use of natural resources. For this reason, in sustainable construction, attention is paid to the use of building structures, components and building products in the planning phase, and their energy consumption is low – the material and energy flows in the manufacture, transport and processing of building materials are assessed by calculating the building material The primary energy content of building materials to non-renewable energies, their share of global warming and acidification – is necessary and are made from renewable raw materials as possible. The raw materials in turn should come from sustainable management. Ecologically sustainable building materials include, for example, wood and clay building materials. Many building materials from renewable raw materials are suitable for thermal insulation , such. B. hemp fiber , flax fiber or sheep’s wool . Ecologically sustainable construction is further characterized by the fact that the transport routes of the building materials to their place of use are as short as possible, so as to keep the energy required low and the material cycles tight. If the building is dismantled, sustainable construction products and constructions can be largely reused or reused. They can thus be recycled safely into the natural material cycles . The use of building materials and constructions with these substances, which have harmful effects on the environment and humans, is therefore avoided or greatly reduced in sustainable construction. These include, for example, halogens , which are used for example in refrigerants , heavy metals such as zinc, chromium, copper, lead and cadmium, the z. B. in plastics or wood preservatives , or volatile organic compounds (VOC) or hydrocarbons , which are used for carpets, floor coverings and coatings. These substances show their negative effect on the construction site or during the use of the building, for example when the materials are exposed to longer-term weathering . In contrast, building materials and structures used in a sustainable building are low in emissions , have little negative impact on the global as well as the local environment, and are not harmful to health.
Insulation and heat protection
An important criterion that influences the heating and thus the energy demand of a building is the thermal insulation. The optimization of structural thermal insulation contributes to reducing the energy consumption of the building, which goes hand in hand with the saving of fossil fuels . This in turn means that natural resources are conserved and CO 2 emissions are reduced. Thermal insulation can be achieved in sustainable building, especially through the thermal building envelope. In most cases, thermal insulation systems are used. In these, a thermal insulation material is attached to the outer wall of the building by means of adhesive. Optimum thermal insulation can be achieved by using insulating materials with low thermal conductivity and with a high overall thickness. Expanded polystyrene, with and without graphite, rock wool and cork, has the best values in LCA in the field of thermal insulation composite systems. Another measure to prevent heat dissipation and thus of energy losses by means of optimized thermal insulation is the heat protection glazing , which has been standard since the introduction of the 3rd Thermal Protection Ordinance in Germany in 1995. Heat-insulating glasses consist of two or three panes. They have heat-function coating (s) of metal. The interpane spaces are filled with a noble gas (usually argon ). When constructing a sustainable building, attention is also paid to avoiding thermal bridges . These arise mainly at the transitions of different components as well as at places where, due to the design, less insulation material can be applied than on the rest of the building.
The operation of a sustainable building is focused on the conservation of natural resources. This is especially true for the energy supply. With 40% of the EU’s total energy needs in 2009 , buildings have a very high energy consumption. In addition to efficient thermal insulation, building technology is optimized in sustainable construction in order to reduce energy consumption. By using renewable energy sources such as solar , geothermal and biomass (and rarely wind and hydro). This reduces the consumption of fossil, non-renewable and increasingly scarce resources such as hard coal , lignite , oil , natural gas and uranium . The use of regenerative energies thus contributes to the reduction of primary energy demand and dependence on fossil fuels (see also Plant Engineering ). In addition to conserving resources, environmental sustainability in the construction sector aims to reduce the emissions of pollutants caused by buildings and their building materials. An essential contribution of sustainable construction to reducing the negative impact on the environment and the climate is the reduction of greenhouse gases through the use of renewable energies. The main cause for the increase of the greenhouse gases and thus for the greenhouse effect are combustion processes of fossil energy sources for energy production. In these processes, carbon dioxide (CO 2 ) and other gases are released with similar damaging effects, which leads to a warming of the earth’s surface and concomitantly to global warming. In contrast, renewable energies are almost completely CO 2 -neutral. The use of renewable energy also reduces the emissions of sulfur and nitrogen compounds , which lead to acidification of the air and soil and have negative effects on water, living things and buildings. Heat and power generation often takes place in sustainable construction using the following renewable energies:
Solar thermal systems are used in the form of solar collectors , especially for heating water. However, since the solar energy required for domestic water heating is not available all year round, the demand can usually only be met by combining solar collectors and existing heating systems. In addition to domestic hot water preparation, solar systems can also be used for heating support. In addition, solar energy for building air conditioning can be combined well with an absorption chiller . Photovoltaic systems are increasingly used for power supply by means of solar energy. They convert the radiant energy of sunlight directly into electricity. With photovoltaic technology, the building can produce electricity for its own supply as well as for feeding it into the public grid .
This alternative to fossil fuels is now quite common. The advantages of the energy source Geothermal heat is that it – unlike solar energy – is available at all times and that it is not subject to temperature fluctuations, which can lead to a loss of performance of the geothermal plants. Geothermal energy uses the energy stored in the earth. The most common method of geothermal use is the conversion of near-surface geothermal heat into heat energy by means of heat pump (s).
The term biomass covers the amount of living and dead plants and animals as well as their metabolites, products and residues on an organic basis, in the context of use and recycling is also spoken of biogenic raw material . The conversion of plants into energy sources takes place by means of different thermochemical processes, so that biomass is available as a solid, liquid or gaseous energy carrier. While fossil transformation products such as coal, oil or natural gas emit carbon dioxide into the atmosphere when burned, the use of sustainable biomass does not affect the carbon cycle, as plants can only release the CO 2 from the air they need to grow. The use of biomass technology thus contributes to the reduction of CO 2 emissions caused by buildings. It also strengthens domestic agriculture and forestry. However, it also has ecological and social disadvantages: Increased production of energy crops threatens to displace food crops and destroy forests. In addition, the combustion of biomass, such as waste wood, ejects the greenhouse gas N 2 O.
In addition to reducing the energy requirements of buildings through insulation, the system technology plays the largest role in reducing the total energy demand and thus of harmful emissions and in the conservation of natural resources. To reduce the harmful effects of buildings on the environment efficient plant technology is essential. The system technology responsible for emissions in buildings is subdivided into:
Plants for heat generation and distribution,
Plants for drinking water supply,
Systems for ventilation and air conditioning,
Systems for compressed air supply as well
The following plant concepts are basically suitable for reducing harmful emissions and conserving natural resources:
Use and storage of renewable energies
(see energy sources)
Use of combined heat and power
Combined heat and power plants are plants that generate electricity and heat at the same time. This will u. a. achieved by combustion engines (gas or diesel units) in conjunction with electric generators for power generation. The waste heat of the engine is z. B. used for heating purposes and for domestic hot water. Systems of this type are also referred to as combined heat and power plants (CHP). An expanded form of combined heat and power is the power-heat-refrigeration coupling, in which by means of absorption chillers from the heat generated by a CHP heat is produced, for. B. for the building air conditioning. Combined heat and power plants are compared to a power production z. B. from conventional power plants in the advantage that the waste heat is used in the production of electricity in CHPs for the most part. Therefore, the overall efficiency of combined heat and power plants is higher than with a separate generation of electricity and heat based on the same energy sources.
Usage-adapted provision of energy, air and water
The provision of energy, air and water as exactly as possible adapted to the usage can significantly reduce the total energy and water requirements of buildings. This is z. B. achieved by an accurate adjustment of the time programs of boilers, circulation and other pumps and ventilation and compressed air systems. In addition, z. B. variable speed motors in pumps, ventilation systems, etc. help to adjust the provision of heating energy, fresh air, etc. as closely as possible to the needs of users.
Heat and cold recovery
Through refrigeration and heat recovery , the total energy efficiency of plants is increased. This can be done for example by the recovery of waste heat from exhaust gases from combustion processes in boilers by means of heat exchangers or by using the resulting cooling energy from heat pump systems for air conditioning buildings or for Nutzkälte. The waste heat from refrigeration systems can be used useful, z. B. in the domestic hot water.
Regular maintenance and inspection of the system technology
Regular maintenance and inspection of the system technology means that defects and malfunctions can be detected and remedied at an early stage. Regular cleaning and checking of settings for the maintenance of the system technology is a prerequisite for a permanently efficient operation of the system technology.
Careful commissioning and adjustment of the system technology
Careful commissioning and adjustment also contribute to the efficient operation of the system technology. In the simplest case, this means the exact commissioning of a boiler according to the manufacturer with the correct setting of all control parameters and time programs and their adaptation to the use, the local conditions and the connected heating technology ( floor heating or radiators , domestic hot water preparation, etc.). The control of the regulation after a running-in period (eg after the start of the heating season) is also part of a careful start-up and adjustment of the system technology. For larger systems commissioning is significantly more complex and requires a so-called commissioning management, z. Eg according to VDI guideline 6039.
Instruction and training of users and operators
Comprehensive instruction and training of users and operating staff ensure energy-efficient operation of the system technology. Particularly noteworthy here are the shutdown of the system technology when not in use and the constant adaptation of time programs to a changing usage. In addition, with the training of the operating personnel, an optimization of the system technology can be achieved during operation and by focusing on an energy-efficient user behavior further savings potential can be utilized.
Water technology and water use
Protecting the resource of water also plays a major role in sustainable construction. The reduction of drinking water consumption is mainly due to the use of water-saving technology, such as efficient installations ( single-lever mixers , rinse stops, etc.). Reducing the amount of waste water is also an efficient way of reducing water demand. For example, gray water (low polluted wastewater through showers) or rainwater can be used for toilet flushing.
Waste generation and environmentally sound disposal
A high proportion of the total waste volume is attributable to construction and demolition waste. In order to minimize this share and thereby reduce the negative effects of the waste on the environment, it is necessary to develop concepts for waste separation , environmentally sound disposal and recycling . It is an important part of planning a sustainable building. A waste concept comprises z. B. Surveys on waste generation for the building, planning of waste separation and provision of recyclable waste containers. Since sustainable construction strives to optimize the factors that influence the life cycle, special consideration is given to the possibility of dismantling . Above all, it serves the protection of natural resources and the avoidance of a high amount of waste. High recyclability allows the return of parts of the building into the natural energy and material cycle. The highest level of this recycling is the reuse of building materials. This is followed by the recycling of building materials for a new product of the same material, as is often the case with copper pipes, or the use of reclaimed materials and components for a non-similar product. Recycled components and materials are, for example, supporting structures, exterior walls, interior walls, ceilings and roof structures. Sustainable building strives to use building materials that can be reused or recycled. The last stages are thermal utilization and landfill of building materials. The amount of material in these stages is minimized in sustainable building through the use of recyclable building materials.
Profitability is another pillar of sustainability. The optimization of the economic aspect in the sense of sustainability means in the field of construction that all phases of the life cycle of the building are taken into account in its economic evaluation. In contrast to conventional planning and construction methods, economic efficiency calculations in sustainable construction do not only capture the investment costs for the construction process. H. its acquisition and construction costs. Rather, a sustainable building is judged on the basis of its entire life cycle. The cost-effectiveness of a planned construction project is assessed by means of a Life Cycle Cost Analysis (LCCA). This total cost calculation includes the following factors:
the cost of producing the building, which also includes the land and planning costs, d. H. the investment costs,
the cost of construction use, which includes the operating costs (ie the media consumption of heating, hot water, electricity, water, sewage), and
the building and component specific costs, such as for cleaning, care and maintenance. This includes the necessary expenses for the dismantling, such. As for demolition, removal, reuse or recycling and disposal.
On the basis of the life cycle cost calculations, the economic efficiency of a building can be identified and assessed. The basis of the costing for the different life cycle phases is set by regulations such as DIN 276 and DIN 18960, in which the expenses for the individual phases are determined and structured. In particular, the cost of use is based on forecasting data, as the evolution of costs depends on a variety of factors, such as the type of use or user behavior. In most cases, the construction follow-up costs incurred in the use and dismantling phase exceed the costs of construction. As the buildings are expected to have a longer useful life, reducing operating and utility costs to minimize lifecycle costs becomes significant.This shows the interactions between ecological and economic factors: In a sustainable building, ecologically oriented measures, such as improved thermal insulation in connection with energy-optimized plant technology using renewable energies, can reduce operating costs. This requires an increased planning requirement, which increases the costs for this phase. On the other hand, in this phase, the ability to control the costs of creation, use and demolition is most effectively achieved through integral planning. The optimization of the life cycle costs in this phase is possible above all by comparing different building designs in their variants.The comparison of possible alternatives in terms of cost-effectiveness makes the savings potential evident and thus serves as a basis for the decision for the most cost-efficient planning variant. This can affect both the entire building and subsystems, such as the technical building system (strategic components). Profitability calculations, which include life-cycle costs, are also relevant for deciding either to build a new building or to re-use an existing building. Furthermore, they help to determine the most economical procurement variant (Profitability calculations, which include life-cycle costs, are also relevant for deciding either to build a new building or to re-use an existing building. Furthermore, they help to determine the most economical procurement variant (Profitability calculations, which include life-cycle costs, are also relevant for deciding either to build a new building or to re-use an existing building. Furthermore, they help to determine the most economical procurement variant (PPP , leasing , contracting , etc.).
In terms of sustainability as the protection of capital as a resource, constant value stability is an important criterion for the economic quality of a building. Its performance is highly dependent on external factors such as market and location development. These factors carry the risk of depreciation, which must already be taken into account in the planning phase. To counteract this risk and thus ensure long-term value stability, a sustainable building must be able to adapt quickly and cost-effectively to changing usage requirements. By focusing on extending the lifetime of sustainable construction, the aspect of third-party use is maintaineda special meaning. It decisively influences the development of the building value, since the possibility of reuse can guarantee the permanent utilization and thus value stability. A contribution to economic optimization is also made by the space efficiency of the building. Space efficiency is achieved when the building surface is so effectively divided and used that construction and operating costs can be reduced.
Socio-cultural and functional quality
The third pillar of the sustainability of buildings are socio-cultural and functional factors. They form the basis for the acceptance and appreciation of a building by its users and by society in general. Social values such as integration, health, quality of life, security and mobility and aesthetic-cultural values such as design are integrated into the construction concept.
Comfort, health and usability
In order to make people feel comfortable in their living and working environment, optimal conditions of use must apply. These are created in sustainable building through measures that fulfill the requirements for health protection, cosiness and user-friendliness. The following criteria determine the socio-cultural and functional quality of a building:
The thermal comfort of a building depends on an optimally comfortable room temperature. This is given in winter at about 21 ° C and in summer at about 24 ° C. The radiant temperature of the surfaces delimiting the rooms must not deviate too much from the room temperature (+/- 4 ° C). The indoor air should not be perceived as too humid or too dry. Draft can be avoided by appropriate structural or technical measures.
A high standard of indoor air quality can be achieved by optimally selecting the building materials used. This selection contributes to the health care of the users and positively influences their smell perception. Construction products such as paints, varnishes, wood preservatives, wood-based materials, floor coverings and adhesives, wall and ceiling coverings, waterproofing, plaster , bricks, cement and concrete contain volatile organic compounds (VOCs) and formaldehyde . The emissions from these building materials are harmful to health and affect the user comfort, as they are perceived as unpleasant due to their high odor intensity. The use of these substances is as far as possible avoided or greatly reduced in sustainable construction. Negative odor sensations are also caused by the users themselves, who consume oxygen and CO 2and produce biological exhalations. Therefore, the possibility of a frequent air change (“airing”) must be given. The air exchange can be done by natural ventilation, which uses the thermals inside the building, or mechanically by means of energy-efficient ventilation systems. This shows that the demands of sustainable construction can conflict with one another: Although a high ventilation rate serves to improve air quality, it is also associated with energy losses. This contradiction can not always be resolved. Rather, sustainable building is about balancing and balancing the different requirements.
The acoustics within a room also affect the well-being and performance of the user. Acoustic comfort is given when the user is exposed to as few external and internal noise sources as possible , since acoustic emissions can influence the ability to concentrate and cause stress. Sound insulation concepts depend on the type of room usage. Especially with open office structures, such as multi-person offices, speech intelligibility, communication and the ability to concentrate can be considerably reduced. This circumstance makes the best possible sound absorption necessary. These are on ceilings and room dividersSound absorbing surfaces attached. Glass acoustic screens or partition wall absorbers can structure the room without restricting the visual contact between the employees. When used as a meeting room, however, a combination of sound-reflecting and sound-absorbing measures is necessary because this type of use requires increased sound transmission.
The visual characteristics of living and working spaces also play an important role in assessing user comfort. The lighting situation in a building is composed of both natural daylight and artificial light . Essential for the well-being and efficiency of users is the presence of sufficient daylight. This can be determined by means of the daylight quotient and can be quantified for different types of spatial use. Also a good visual connection to the outside is important. These criteria can, for. B. be satisfied by sufficiently large windows with optimal alignment. The natural light sources should be equipped with a protection device against glare and overheating and ensure sufficient shading. However, these shading systems must not or only to a small extent prevent the view to the outside. The exposure system for frequently used surfaces, such as work surfaces , is integrated into the visual concept in sustainable building. Here we recommend a combination of direct and indirect lighting, This compensates for the adverse effects of both types of lighting. Thus, the reflected glare or the shadows, which can occur in direct lighting, reduced by indirect lighting. In this case, the luminous flux is deflected to the ceiling or the walls of the room, from where it is reflected on the required surfaces. It creates diffused light that can limit the spatial perception . This adverse effect can in turn be compensated by direct illumination, which sharpens the contrasts.
Influence of the user
The above socio-cultural criteria determine the satisfaction of the user. However, since the needs of the user are individual, he must be able to influence the regulation of ventilation , sun and glare protection, temperature during and outside the heating season, and artificial light itself to ensure his individual comfort. This creates a high acceptance of the used premises. The installations for regulating the installations must also be easy to operate.
Socio-cultural criteria that increase the user’s sense of comfort also affect safety. A subjective sense of security is generated, for example, by technical alarm devices such as fire and burglar alarm systems, by a sufficient illumination of the outdoor facilities and by a clear routing. The presence of a security service, for example, outside of normal working hours, increases the sense of security. These measures are designed to prevent hazards, attacks, disasters and accidents. An optimal safety concept also includes the planning of escape routes and evacuation facilities in the event of accidents and disasters, measures to reduce combustion gas and smoke .
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