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Development of Life-Cycle Based Strategies Towards Buildings With a Positive Ecological Footprint Using Thermal Building Simulations

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The goal of this study is to develop life cycle based implementation strategies for the realization of buildings with a positive ecological footprint (EF). Since there is no methodological approach existing which covers this topic, first a method was developed to calculate the ecological land demand of buildings (the area required for ecological compensation of the buildings` emissions-construction, operation and disposal). The developed method takes the actual compensation capabilities of habitats into account and links the life cycle assessment (LCA) results to those capabilities. With this approach an estimation of the EF is made possible. Even with applying optimization algorithms an eco-positive building was not achieved. Therefore, further approaches need to be investigated. Key Innovations  Development of a calculation methodology to quantify the ecological land demand (ELD) of life-cycle based emissions of buildings  Optimization algorithms are used based on the results for the (ELD) of a case study Practical Implications This research is relevant since it provides a methodology to calculate the ecological land demand of a building in order to compensate building emissions. It can be used to further develop and quantify alternative planning concepts, which is necessary for achieving eco-positive buildings on a life-cycle basis.
Development of Life-Cycle Based Strategies Towards Buildings With a Positive Ecological
Footprint Using Thermal Building Simulations
Michael Vollmer1, Hannes Harter1, Kathrin Theilig1, Daniel Kierdorf1, Werner Lang1
1Institute of Energy Efficient and Sustainable Design and Building, TU Munich, Munich, Germany
The goal of this study is to develop life cycle based
implementation strategies for the realization of buildings
with a positive ecological footprint (EF). Since there is no
methodological approach existing which covers this topic,
first a method was developed to calculate the ecological
land demand of buildings (the area required for ecological
compensation of the buildings` emissions construction,
operation and disposal). The developed method takes the
actual compensation capabilities of habitats into account
and links the life cycle assessment (LCA) results to those
capabilities. With this approach an estimation of the EF is
made possible. Even with applying optimization
algorithms an eco-positive building was not achieved.
Therefore, further approaches need to be investigated.
Key Innovations
Development of a calculation methodology to
quantify the ecological land demand (ELD) of
life-cycle based emissions of buildings
Optimization algorithms are used based on the
results for the (ELD) of a case study
Practical Implications
This research is relevant since it provides a methodology
to calculate the ecological land demand of a building in
order to compensate building emissions. It can be used to
further develop and quantify alternative planning
concepts, which is necessary for achieving eco-positive
buildings on a life-cycle basis.
In today’s strive for a sustainable and eco-positive future
the building sector plays a major role. On a global scale
the building sector is responsible for 35% of the total
energy demand. Furthermore, the associated CO2-
emissions amount up to 38% worldwide. (UN, IEA 2020)
Based on the growing scientific and political awareness
and in the context of sustainable development, a wide
range of implementation strategies have been emerged.
This led for example to a European wide arrangement, the
European Green Deal. The goal is to increase the
sustainable development and set strict requirements
(European Commission, 2019). However, most of those
strategies are based on the eco-efficiency approach, which
aims to reduce negative environmental impacts, e.g.
reducing CO2-emissions (Braungart et al., 2007).
According to McDonough & Braungart the application of
sustainability principles can only lead to a short term gain.
They state, that from a design aspect the system is
fundamentally flawed, which can only lead to a reduction
in resource consumption and pollution. (McDonough et
al., 2003)
Hence the impacts buildings and humans have on the
environment can ultimately only be less-bad
(McDonough et al., 2003). The necessity to change the
standpoint from a less-bad to positive perspective is
shown in particular by identifying the effects mankind has
on the environment.
According to Sanderson et al., mankind influences over
80% of the global terrestrial biosphere (except Greenland
and Antarctica) (Sanderson et al., 2002). Furthermore,
since human lifetime one-third of the biodiversity has
been lost (Millennium Ecosystem Assessment, 2005).
This is especially alarming since ecosystems provide vital
services to humans (Millennium Ecosystem Assessment,
2005). According to the German Environment Agency
(GEA, 2018) air pollutants are the main risk for terrestrial
ecosystems along climate change. This is accompanied by
the risk of loss of biodiversity. To ensure the growth of
ecosystem services and enrichment of biodiversity, the
eco-efficient approach must be replaced by an eco-
effective one, which provides positive effects on the
environment (Birkeland et al., 2016). There are already
established concepts such as the cradle-to-cradle design
concept (Braungart et al., 2007) and “Regenerative
design (Mang et al., 2013).
A major problem with those design concepts is the lack of
quantification regarding specific requirements and
implementation strategies. However, only with a
quantification one can understand the magnitude of the
impact especially a building has on the environment (on a
local, regional and global scale). Therefore, the goal of
this research is a) to develop a methodology to quantify
the ecological land demand (ELD) of buildings over their
life cycle, b) to develop implementation strategies,
planners and architects can apply during the planning
stages in order to get towards a positive ecological
footprint and c) to provide solutions for adequate
ecological compensation measures. Since the
understanding of ecosystems, buildings and their
interactions is highly complex, the goal is to develop the
methodology according to the principle of Occam’s Razor
and make it as simple and understandable as possible
(Gibbs et al., 1997).
State of the art
The basis for sustainable buildings are provided by laws,
standards, guidelines and certification systems as well as
international environmental agreements which aim to
minimize environmental pollution. However, the
requirements and framework conditions set out in these
agreements, such as the conservation of fossil raw
materials for energy purposes and the avoidance and
mitigation of hazardous substances, waste and emissions,
are not sufficient.
In Germany the Environmental Damage Act (USchadG)
serves to transpose Directive 2004/35/EC into national
law and applies as soon as environmental damage occurs
or there is an imminent risk of such damage to the
environment. Responsible parties are also obligated to
avert and remedy the environmental damage that has
occurred (USchadG, 2007). Nature and landscape fulfill
crucial functions for human life and health (BNatSchG,
2009). For this reason, the Nature Conservation and
Landscape Management Act (BNatSchG) ensures the
protection of these assets by not impairing them more than
it is required by the circumstances. If this primarily
considered avoidance cannot be guaranteed, greater
impairments are to be compensated by compensatory or
substitute measures.
The biotope value procedure according to the Federal
Compensation Ordinance (BKompV, 2020) illustrates the
type and extent of compensation required due to an
intervention in nature and the landscape. The construction
of a building constitutes such an intervention, so that the
determination of the extent of compensation is required.
However, the biotope value procedure has only limited
informational value about how buildings interfere with
nature and landscape. When determining the need for
compensation for the area occupied, only the building site
itself is considered. The effects caused by the extraction
of raw materials for the building materials and respective
emissions at other locations are not included in the
procedure. (BKompV, 2020)
Furthermore, there are significant barriers e.g. rise of
complexity, pluralism meaning of terms regarding
sustainability and the lack of adapting new ways of
thinking in achieving ecological positive buildings
(Ankrah et al., 2013). Since there is no methodology
which explicitly enables the calculation for the ecological
footprint of buildings it is evident that there is need to
develop such a methodology.
Project description
The developed and described methodology to determine
the ELD to compensate building emissions and the
possible strategies to reach an ecological positive building
are based on an ongoing research project called
Ferdinand Tausendpfund - Lebenszyklusanalyse und
Gebäudemonitoring’ of the Institute of Energy Efficient
and Sustainable Design and Building of TU Munich in
cooperation with the construction company Ferdinand
Tausendpfund GmbH & Co. KG (Vollmer et al., 2019).
The case study is a three storey office building, located in
Regensburg, Germany. The characteristics of the building
are summarized as follows:
Area thermal envelope: A = 1,720m²
Gross volume: Ve = 4,246m³
Air volume: V = 3,397m³
Net floor area: ANF = 1,097m²
As a base case the technical building equipment as well
as the thermal properties of the thermal building envelope
are set according to the reference building defined in the
Act on the Conservation of Energy and the Use of
Renewable Energies for Heating and Cooling in Buildings
(GEG, 2020). The base case is used as a reference to
compare the total ELD with the optimized building.
The fundamental methodology is used to a) quantify the
effects buildings have on the environment and to b)
identify implementation strategies as is displayed in
Figure 1. This approach allows a time efficient estimation
and optimization of buildings regarding their effects on
Figure 1: Schematic overview of the applied methodology
the ecosystem and the needed compensation for building
The whole process is divided into three parts:
Part A Ecosystem-specific assessment,
Part B Analysis and
Part C Optimization.
Part A Ecosystem-specific assessment
Life Cycle Assessment (LCA)
In the first part necessary boundary conditions regarding
the building performance simulation (BPS) and LCA are
defined. At first, the set-room-temperatures for the
simulations are defined to 21°C Tair 26°C in order to
ensure a comfortable indoor climate (ASR A3.5, 2010).
Furthermore, the system boundaries and the materials
which have to be included in the LCA are defined. The
LCA is calculated according to DIN EN ISO 14040 (DIN
EN ISO 14040), DIN EN ISO 14044 (DIN EN ISO
14044) and DIN EN 15978 (DIN EN 15978). For the life
cycle impact assessment (LCIA) the freely accessible
database OEKOBAUDAT 2020-II with specific datasets
for building products, provided by the German Federal
Ministry of the Interior, Building and Community, is used
(Federal Ministry of the Interior, Building and
Community, 2020). The ecological impacts of the
building are calculated for the impact indicators Global
Warming Potential (GWP) in kilograms CO2-equivalents
[kg CO2-eq.], Acidification Potential (AP) in kilograms
SO2-equivalents [kg SO2-eq.] and Eutrophication
Potential (EP) in kilograms PO4-equivalents [kg PO4-eq.].
The building assessment is based on the building life
cycle stages according to DIN EN 15804 (DIN EN 15804)
for the life cycle stages A1 - A3 Production stage, B6
Operational energy use and C1 - 4 End of Life. Regarding
the lifespan of the building a lifespan of 50 years is
considered. The building construction (BC) include
external walls, roof, ceilings, foundation, indoor walls and
windows. The LCA of the buildings use stages (BUS)
includes, energy demand heating, energy demand cooling
and electricity demand for lighting. The LCA of the
technical building services (TBS) includes the energy
system (the respective units itself), heat transfer system
(e.g. tubes), photovoltaic modules and mounting system
and solar thermal modules and mounting system.
As an output of the building LCA one gets the total
amount of emissions for the calculated time period and
   
   
   
GWP = Global warming potential in [t CO2-eq.],
EP = Eutrophication potential in [kg PO4-eq.],
AP = Acidification Potential in [kg SO2-eq.] total amount
over the whole life cycle (tot), building construction (BC),
buildings use stage (BUS), technical building services
Since the quantity of emissions is determined, a direct
ecological assessment is not possible at first.
Nevertheless, by taking the actual compensation
capabilities of habitats into account and linking the LCA
results to those capabilities, an estimation of the EF is
made possible.
Ecological Land Demand (ELD)
The ELD is defined as the equivalent amount of annual
area a building needs to compensate (ELD is negative) for
the life cycle based emitted emissions or provides (ELD
is positive) for compensation, according to the ecological
indicators GWP, AP and EP. It is given in hectare-
equivalents per year [ha-eq./a]. The methodological
procedure for calculating the ELD is done separately for
the different building emissions GWP, AP and EP. The
different steps of calculation are explained as follows.
Global Warming Potential
For calculating the ecological land needed to compensate
the building emissions for GWP in [kg CO2-eq.] the
calculated emissions are divided by the mean CO2-
sequestrations rate of German forests. According to
Bastin et al. restoration of trees has, on a global scale, high
potential in reducing climate change and therefore, this
strategy is also pursued within the framework of this
methodology (Bastin et al., 2019). It is essential to take
into account that the average CO2-sequestrations rate
depends on the extent of deforestation, afforestation and
the remaining forest area. Based on the extent of
compensation required due to the Federal Compensation
Ordinance (BKompV, 2020) and German Nature
Conservation and Landscape Management Act
(BNatSchG), measures must be taken from the start of the
construction project to compensate for the CO2-
emissions. It is assumed that only the option of
reforestation is suitable, since the CO2-sequestrations
capabilities of existing forests are already being used for
existing emissions. The sequestrations capabilities used in
this calculation approach are based on the findings of the
Carbon Inventory 2017 for Germany (Riedel et al., 2017).
For reforestation the rates depend on the tree type as well
as the age of the tree. Since a building lifespan of 50 years
is considered, only the sequestrations rates for trees up to
that age are relevant which are displayed in Table 1.
Table 1: Mean sequestrations rates according to tree
age (Riedel et al., 2017)
Age in [a]
Sequestrations rate of CO2
1 20
21 - 40
41 - 60
The calculation of the ELD for CO2, see equation (4), is
calculated by dividing the total amount of GWP by the
sequestrations rates considering tree growth.
 
 
 
ELD(GWP) = Ecological land demand needed to
compensate life cycle bases CO2-eq. Emissions in
[ha-eq./a]; GWPtot = Total global warming potential for
the whole building in [t CO2-eq.]; SeqR1-20 =
Sequestration Rate for trees age 1-20 in [t CO2/ha/a];
SeqR21-40 = Sequestration Rate for trees age 21-40 in
[t CO2/ha/a]; SeqR41-60 = Sequestration Rate for trees age
41-60 in [t CO2/ha/a]; a = duration of years; a1-20 = 20;
a21-40 = 20; a41-50 = 10
Eutrophication and Acidification
Equivalent to the calculation for ELD(GWP) the
regeneration capabilities of habitats for eutrophication
and acidification is applied. This developed
methodological approach allows the ecosystem-specific
assessment (ESA) of life cycle based emissions of
buildings. This is made possible by quantitatively linking
the results of the building LCA with the Critical Load
Approach. The fundamental idea of the Critical Load
Approach is to take the natural regeneration capabilities
of habitats into account and evaluate how much
depositions are possible until harmful effects to the
habitat are expected (CLRTAP, 2017). This threshold is
then called the critical load, which is defined as:
“A quantitative estimate of an exposure to one or more
pollutants below which significant harmful effects on
specified sensitive elements of the environment do not
occur according to present knowledge” (Nilsson et al.,
The main advantage of this process is, that it connects the
results of the LCA with the actual ecological critical loads
of specific habitats. The fundamental calculation process
for the respective critical loads for eutrophying and
acidifying air pollutions, are explained according to
(CLRTAP, 2017) as follows.
The critical loads for eutrophying nitrogen compounds
for the protection of biodiversity are calculated as
follows, see Equation 5.
  󰇛
CLnutN = Critical Load for eutrophic nitrogen in
[kg N ha-1 a-1]; Nu = Net nitrogen uptake rate by
vegetation in [kg N ha-1 a-1]; Ni = net nitrogen
immobilization rate [kg N ha-1 a-1]; PS = Leachate rate
[m3 ha-1 a-1]; [N]crit(bdiv) = Critical N concentration in
leachate [kg m-3].
The critical loads for acidifying sulphuric compounds for
the protection of biodiversity are calculated as follows,
see equation 6.
 
CLmaxS = Critical Load for sulphur compounds
[eq ha-1 a-1]; BC*dep = sea salt corrected rate of deposition
of basic cations [eq ha-1 a-1]; Cl*dep = sea salt corrected
rate of deposition of cloride ions [eq ha-1 a-1]; BCw = rate
of release of basic cations by weathering;
Ca2++Mg2++K++Na+ [eq ha-1 a-1]; Bcu = net uptake rate of
basic cations by vegetation, Ca2++Mg2++K+ [eq ha-1 a-1];
ANCle(crit) = Critical discharge rate of acid
neutralization capacity with leachate [eq ha-1 a-1]; eq =
one equivalent, which equals 16 kg of sulfur in the form
of sulfate
The necessary inputs for the displayed calculations have
to individually be measured or be estimated by experts on
the basis of existing measurements. For Germany the
habitat-specific critical loads are mapped and published
by the German Environment Agency (GEA, 2018).
The respective critical loads are highly regionally
dependant, meaning the critical load of e.g. forests can
vary between 3.8 kg N·h-1·a-1 up to 20 kg N·h-1·a-1
(GEA, 2018). On the other hand, building emissions are
not regionally based, e.g. if one takes a look at the energy
grid and its energy generation it is evident that the plants
are spread all over Germany. The same applies to the
production process of materials and their resource
extraction. In order to be able to calculate the ELD, the
following simplifications and assumptions are made:
The system boundaries are set to the state borders of
The life cycle bases building emissions according to
the results of LCA a distributed evenly over Germany
In the calculation of the ELD for building emissions,
the required area is based on the average critical load
values of all habitats investigated in Germany
According to the German Environment Agency (GEA,
2018) the investigated habitats in Germany have the
following mean critical loads, taking the protection of
biodiversity into account:
Mean CLSmax approx. 22,1 kg S·h-1·a-1
Mean CLNmax approx. 12,7 kg N·h-1·a-1
The habitats Forests, Heaths, Moors, Swamps, Waters and
Grasslands were examined.
Calculating the respective ELD for EP and AP
The calculation process for the ELD for EP and AP is
equivalent to that of ELD for GWP. The total respective
ELD are calculated by dividing the total amounts of EP
and AP by the mean critical loads.
󰇛󰇜 
 
ELD(EP) = Ecological land demand needed to
compensate life cycle bases Phosphate-eq. Emissions in
[ha-eq./a]; ELD(AP) = Ecological land demand needed
to compensate life cycle bases SO2-eq. Emissions in
[ha-eq./a]; EPtot = Total eutrophication potential for the
whole building in [kg Phosphate-eq.]; APtot = Total
acidification potential for the whole building in [kg SO2-
eq.]; CFP-N = Characterization factor for the conversion
of phosphate to nitrogen; CFSO2-SO4 = Characterization
factor for the conversion of SO2 to SO42-
The EP of LCA is given in kg Phosphate-eq. and since the
critical load for EP is based on nitrogen, a conversion has
to be carried out. Given the characterization factors
according to (Leiden University, 2016) phosphate can
converted to nitrogen by multiplying it with the factor
CFP-N = 0.42.
Regarding the acidification potential, it has to be taken
into account that the SO2 is the main anthropogenic
pollutant and is converted in the atmosphere to SO42-.
Different studies have shown that the conversion rate in
[h-1] from SO2 to SO42- is dependent of the composition of
the atmosphere. Also the time aspect regarding the
conversion rate is not taken into account in the calculation
of the ELD and it is therefore assumed that the
characterization factor CFSO2-SO4 = 1, this is possible due
to the fact that one SO2 converts to one SO42-. (Eatough et
al., 1994)
The final step of the calculation process is distributing the
calculated ELD to the individual habitats according to
their relative share, see Table 2. The ELD(GWP) is only
accounted for forests. To avoid double accounting in
calculating the total ELD, only the respective maximums
of each individual habitat calculation are taken into
account, see Table 3.
Table 2: Floor area total according to types of use in
Germany (Statistisches Bundesamt, 2020; Bundesamt für
Naturschutz, 2014)
in [%]
Part B Analysis
Process analysis
Before the optimization can be carried out, parameters
have to be selected. In a first process analysis, the whole
planning and calculation process of the case study is
analysed regarding parameters, which planners can
influence. A total amount of 112 individual parameters
are identified regarding the categories, Technical building
services (TBS), Building construction (BC), Life Cycle
Assessment (LCA), Building and Users. Since the
methodology is applied to an already planned building,
some of the parameters are set and cannot be further
changed, e.g. window area, orientation of the building,
size of the building, building location. If one plans a new
building, those parameters have to be taken into account.
Subsequently, the parameters were further reduced to 21
by means of a literature review and setting certain
boundary conditions.
Table 3: Calculation and distribution of all calculated
respective ELD and total ELD
Ecological Land Demand (ELD)
Sensitivity analysis
Those identified parameters are then used in a simple
local sensitivity analysis (SA) for the baseline by using
the One-at-a-time (OAT) method. The parameters with
units and the examined resolutions are listed in Table 4.
Regarding parameter 19 construction type, the
following types were analysed:
Massive construction with reinforced concrete for
external walls, ceilings, foundation and roof
Monolithic construction with brick walls and
reinforced concrete for the ceilings, foundation and
Solid Wood construction for external walls, ceilings,
and roof. The foundation is made of reinforced
Regarding parameter 20 energy system type, the
following types were analysed:
Boiler (Gas; Wood Pellets)
District heating (Biogas; Biomass; Gas; Coal)
Heat pump (Air-Water-Heat Pump)
Regarding parameter 21 Electricity mix the decisive
relevance is the share of renewable energies. The
scenarios were analysed, with according data for the years
2020, 2030, 2040, 2050, 2060 and from OEKOBAUDAT
2020-II (Federal Ministry of the Interior, Building and
Community, 2020). As a result of the SA, the parameters
which don’t have an impact on the ecological land
demand are excluded; only those who have an impact are
then further used in the thermal building
simulation/optimization (see Figure 1, Part B.4).
Table 4: Parameters with units and resolution used in
the sensitivity analysis
Thickness insulation ext.
0.02 0.50
Thickness insulation roof
0.02 0.50
Thickness insulation
0.02 0.50
Solar gain factor of sun
shading (Fc-Value)
0.15 0.65
Solar heat gain coefficient
of glazing (g-Value)
0.3 0.75
U-Value of windows
0.6 2.9
Luminous efficacy of
10 - 160
Infiltration rate
0.3 3.0
Area of Photovoltaics
0 - 100
Angle of Photovoltaics
0 - 90
Orientation Photovoltaics
-180 - +180
Area of solar thermal
0 - 100
Angle of solarthermal
0 - 90
Orientation solarthermal
-180 - +180
U-Value Hot water tank
0.1 1.0
U-Value Cold water tank
0.1 1.0
Volume Hot water tank
0.1 2.0
Volume Cold water tank
0.1 2.0
Construction type
3 types
Energy system type
7 types
Electricity grid
Part C Simulation and Optimization
In the last part, the ELD is finally incorporated into the
software IDA ICE 4.8 SP 2 using the option of graphical
scripting. This is necessary since the optimization is
aimed to optimized the ELD of the whole building over
its life cycle. The SA delivers the necessary parameters
which have a significant effect on the ELD and can
therefore be optimized. The optimization algorithms
Generalized Pattern Search Particle Swarm Optimization
with Constriction Coefficient Hooke-Jeeves, which are
already implemented in IDA ICE, were used for
Sensitivity Analysis
The evaluation of the SA is based on the mean values and
standard deviation. Parameters with a low mean value and
a high standard deviation have a positive effect on the
reduction of the ELD, see Figure 2. Based on the SA, the
parameters 7, 15, 16, 17 and 18 have low influence on the
total ELD, and are therefore not taken into account for the
optimization. The most influential parameter is the energy
system type with a mean ELD of μ* = 2.41 ha-eq./a and a
standard deviation of σ = 0.405. It is followed by the
construction type of the building with a mean ELD of
μ* = 2.34 ha-eq./a and a standard deviation of σ = 0.263.
Furthermore, the electricity grid mix, U-Value of the
windows as well as the insulation thicknesses of the
external wall and roof also have high impacts.
Figure 2: Results of the SA for the identified parameters
As for parameter 19 construction type, it is apparent that
the solid wood construction has the lowest ELD and is
therefore considered in the optimization (see Table 5).
As for parameter 20 energy system type, district heating
(with biomass), heat-pump and a boiler with wood pallets
indicate the lowest total ELD and are therefore considered
in the optimization (see Table 5).
As for parameter 21 electricity mix, this parameter was
just used to show the importance of a renewable energy
grid. Based on the standard deviation it can be seen that
this parameter has a high influence. Nevertheless, for the
optimization this parameter will be neglected. The
electricity grid mix based on the year 2020 will be used.
The optimization process took 739 individual simulations
to find the best combination of different parameters. The
optimization process alone took 175 hours using a
computer with an Intel® Xeon® 5220 CPU with 18 cores
and 64GB of ram. The optimized values for each
parameter are shown in Table 5.
Table 5: Values of the optimized parameters
Thickness insulation ext.
Thickness insulation roof
Thickness insulation
Solar gain factor of sun
shading (Fc-Value)
Solar heat gain coefficient
of glazing (g-Value)
U-Value of windows
Infiltration rate
Area of Photovoltaics
Angle of Photovoltaics
Orientation Photovoltaics
Area of solar thermal
Angle of solarthermal
Orientation solarthermal
Construction type
Energy system type
Compensation Area for Building Emissions
As a reference, the calculated total ELD for the base case
amounts to ELD(tot) = 2.67 ha-eq./a. Taking the
optimization into account as well as the optimized
parameters (see Table 5) the total ELD amounts to
ELD(tot) = 1.12 ha-eq./a (see Table 6). It can be seen that
the optimization has reduced the ELD by 1.52 ha-eq./a,
which equals a relative reduction of -58,1%.
Table 6: Total ELD for the optimized building
Ecological Land Demand (ELD)
The developed methodology delivers an overview of the
ecological land demand which is needed to compensate
building emissions. With regard to building regulations
and especially environmental ethics and justice,
compensation in general must be critically questioned,
since in worst case it can lead to the exploitation of third
world countries by using their land for compensation.
Therefore, for the further development and
implementation in particular, additional experts from
other disciplines, such as construction botany and
biology, need to be involved. For the described results it
is evident that the ELD(tot) is positive, which means that
compensation is needed for the building emissions and
hence, an eco-positive building was not achieved with the
used optimization method. The ELD of the base case
equals ELD(tot) = 2.67 ha-eq./a. Making use of
optimization algorithms, a reduction of the total ELD to
1.12 ha-eq./a was achieved. This equals a relative
reduction of -58.1%. Looking at the distribution
according the different habitat types it can be seen, that
the compensation area needed to compensate the total
GWP in [kg CO2-eq.] is the highest with 0.88 ha-eq./a. To
compensate for AP and EP a total compensation area of
0.24 ha-eq./a is needed. Also noteworthy are the actual
thicknesses of the insulation for the external walls, roof
and foundation. It can be seen that regarding the thickness
of the thermal insulations, there is a respective life-cycle
based sweet spot. Increasing the thickness of the thermal
insulation is not target-oriented and would ultimately
result in an increase of the total ELD. Approaches such as
the passive house are potentially therefore very
questionable from a life cycle perspective. Looking at this
rather conventional approach to building optimization, it
is also clear that other approaches are needed in order to
be able to achieve an eco-positive building. A renewable
energy grid as well as the use of renewable materials is
needed. Furthermore, other aspects have to be looked at,
such as sufficiency, making use of secondary materials,
keeping materials in a circular economy, creating
compensation areas on the building site (e.g. green roofs
or green walls) and creating an actual eco-positive
material certificate. A paradigm shift in the built
environment is needed to realize eco-positive buildings
for future generations.
This study has shown a methodology to calculate the
ecological land demand a building needs to compensate
its emissions or provides as an emission sink. It can be
seen that with conventional approaches, as we still deal
with in today’s building practice, it is not possible to
realize eco-positive buildings. Also the concept of
compensation has to be discussed further, since important
disciplines such as environmental ethics and
environmental justice must be taken into account. In order
to deal with climate change and environmental protection
we have to change from a less-bad to a positive approach.
is necessary. In addition, a fundamental change in
building regulations is needed. One promising possibility
is to quantify and apply alternative ways of thinking such
as Cradle to Cradle or Regenerative Design.
The presented study is partly based on research conducted
in the project Ferdinand Tausendpfund -
Lebenszyklusanalyse und Gebäudemonitoring, funded
by the Bavarian Building Industry Foundation (BBIV).
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Technical Report
Full-text available
The aim of the research project is to develop implementation strategies for the realization of ecologically and economically optimized serial type houses for affordable housing. Existing obstacles in regard to the realization of cost-effective and ecological buildings in affordable housing will be identified and suitable measures will be developed. The results will be processed and systematized in such a way, that they can be applied to other housing projects and buildings.
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The potential for global forest cover The restoration of forested land at a global scale could help capture atmospheric carbon and mitigate climate change. Bastin et al. used direct measurements of forest cover to generate a model of forest restoration potential across the globe (see the Perspective by Chazdon and Brancalion). Their spatially explicit maps show how much additional tree cover could exist outside of existing forests and agricultural and urban land. Ecosystems could support an additional 0.9 billion hectares of continuous forest. This would represent a greater than 25% increase in forested area, including more than 200 gigatonnes of additional carbon at maturity.Such a change has the potential to store an equivalent of 25% of the current atmospheric carbon pool. Science , this issue p. 76 ; see also p. 24
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An answer to the Frequently Asked Question originally from the usenet physics FAQ 1997
Conference Paper
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Sustainable building development focuses on achieving buildings that meet performance and functionality requirements with minimum adverse impact on the environment. Such eco-efficiency strategies are however not feasible for achieving long-term economic and environmental objectives as they only result in damage reduction without addressing design flaws of contemporary industry. The cradle-to-cradle (C2C) design philosophy which has been described as a paradigm changing innovative platform for achieving ecologically intelligent and environmentally restorative buildings appears to offer an alternative vision which, if embraced, could lead to eco-effectiveness and the achievement of long-term environmental objectives. Adoption of C2C principles in the built environment has however been hindered by several factors especially in a sector where change has always been a very slow process. From a review of extant literature, it is argued that the promotion of current sustainable and/or green building strategies - which in themselves are not coherent enough due to their pluralistic meanings and sometimes differing solutions - are a major barrier to the promotion of C2C principles in the built environment. To overcome this barrier to C2C implementation, it is recommended that research should focus on developing clearly defined and measurable C2C targets that can be incorporated into project briefs from the inception of development projects. These targets could enable control, monitoring and comparison of C2C design outcomes with eco-efficient measures as well as serve as a guide for project stakeholders to achieve eco-effective “nutrient” management from the project conceptualization phase to the end of life of the building.
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In our review of the literature concerning sustainable architecture, we find a remarkably diverse constellation of ideas that defy simple categorization. But rather than lament the apparent inability to standardize a singular approach to degraded environmental and social conditions, we celebrate pluralism as a means to contest technological and scientific certainty. At the same time, we reject epistemological and moral relativism. These twin points of departure lead us to propose a research agenda for an architecture of reflective engagement that is sympathetic to the pragmatist tradition.
Cradle-to-cradle design is an ecologically intelligent approach to architecture and industry that involves materials, buildings and patterns of settlement which are wholly healthful and restorative. Unlike cradle-to-grave systems, cradle-to-cradle design sees human systems as nutrient cycles in which every material can support life. Materials designed as biological nutrients provide nourishment for nature after use; technical nutrients circulate through industrial systems in closed-loop cycles of production, recovery and remanufacture. Following a science-based protocol for selecting safe, healthful Ingredients, cradle-to-cradle design maximizes the utility of material assets. Responding to physical, cultural and climactic settings, it creates buildings and community plans that generate a diverse range of economic, social and ecological value in industrialized and developing countries.
Biodiversity offsetting is used in both urban development and regional resource consent processes to compensate for unavoidable environmental impacts. Using North American, Australian and New Zealand examples, the limitations, opportunities and contradictions of the conventional approach in biodiversity offsetting schemes relevant to the built urban environment were reviewed. It was found that there is not adequate accounting for incremental and cumulative effects over time and space, especially given ecological uncertainty. Benchmarking against current conditions has sanctioned a gradual loss of ecological carrying capacity and biodiversity. Net biodiversity gains are possible, but this will require shifts in frameworks for assessing both buildings and biodiversity offsets towards net positive planning and design.
The atmospheric chemistry responsible for the conversion of SO2(g) to particulate sulfate in areas impacted by anthropogenic emission of SO2 is reviewed. The major reaction mechanism for the homogeneous conversion process in the absence of clouds or fog is the oxidation of SO2(g) by the hydroxyl radical. The rate of this conversion process increases with both increasing temperature and relative humidity. Correlations are described for the effects of these two variables on the conversion process, and equations given which correlate all of the available literature data for the homogeneous conversion process in ambient atmospheres. The conversion of S(IV) to sulfate via aqueous solution chemistry in clouds and fog is more complex and dependent on several variables, including concentrations of the principal oxidants (hydrogen peroxide and ozone), ammonia, droplet size and composition, and meteorology. The gas-phase homogeneous conversion process can vary from less than 1% SO2(g) converted per hour to a maximum of about 10% converted per hour at high temperature and relative humidity. In contrast, the rate of conversion of S(IV) to sulfate in the aqueous-phase homogeneous process is controlled by mixing and reactant limitations, rather than kinetic considerations. The process can involve 100% SO2 converted per hour under optimum conditions. Consequences of the various conversion processes on environmental quality are briefly illustrated with a discussion of the impact of sulfate-containing aerosols on PM10 concentrations and visibility degradation.
Eco-effectiveness and cradle-to-cradle design present an alternative design and production concept to the strategies of zero emission and eco-efficiency. Where eco-efficiency and zero emission seek to reduce the unintended negative consequences of processes of production and consumption, eco-effectiveness is a positive agenda for the conception and production of goods and services that incorporate social, economic, and environmental benefit, enabling triple top line growth.Eco-effectiveness moves beyond zero emission approaches by focusing on the development of products and industrial systems that maintain or enhance the quality and productivity of materials through subsequent life cycles. The concept of eco-effectiveness also addresses the major shortcomings of eco-efficiency approaches: their inability to address the necessity for fundamental redesign of material flows, their inherent antagonism towards long-term economic growth and innovation, and their insufficiency in addressing toxicity issues.A central component of the eco-effectiveness concept, cradle-to-cradle design provides a practical design framework for creating products and industrial systems in a positive relationship with ecological health and abundance, and long-term economic growth. Against this background, the transition to eco-effective industrial systems is a five-step process beginning with an elimination of undesirable substances and ultimately calling for a reinvention of products by reconsidering how they may optimally fulfill the need or needs for which they are actually intended while simultaneously being supportive of ecological and social systems.This process necessitates the creation of an eco-effective system of “nutrient” management to coordinate the material flows amongst actors in the product system. The concept of intelligent materials pooling illustrates how such a system might take shape, in reality.