The worldwide pandemic of SARS‐CoV‐2 which causes coronavirus disease 2019 (COVID‐19) has resulted in first‐time responses in recent history as most of affected countries are confining residents to ...their homes. When sick people are detected, home quarantine is usually recommended because of the lack of available hospital rooms for first‐stage symptoms that do not require constant medical monitoring. In this situation, one can thus wonder about the transmission of the disease to other household members. In this paper, we numerically investigate the transport of the aerosol generated by an infected person quarantined to his bedroom to the other rooms in a typical French detached house by performing TRNSYS‐CONTAM simulations. The intent here is to assess the exposure concentration to the virus of the other household members when simple strategies are employed to reduce the risk of airborne transmission. Due to the uncertainty regarding the evaluation of different parameters such as the emission of contaminated droplets and the infectivity of the occupants, critical cases have been considered in this study. The main results show that, even if remediation actions lower the exposure of other occupants, the risk of contamination remains high even if the contagious person is quarantined to its bedroom.
The external environmental conditions in tropical cities are hot due to high temperatures and humidity. Strategic planning and design of exterior spaces can reduce energy consumption for building ...cooling by reducing various negative effects of tropical climate factors. The desired interior conditions of the building should be similar to the exterior microclimatic conditions. If the microclimate deviates significantly from this, large amounts of cooling energy may be required to create a comfortable interior environment. In this study, single-family houses were randomly selected in two well-planned cities in Malaysia, with 30% of the houses located in Putrajaya and 70% in Shah Alam. Most of the houses used a modern tropical building style to adapt to the challenging tropical climate with high temperatures, high humidity, and heavy downpours. Since air conditioning is the only ideal active system, 90% of the houses in the study areas were operated with this system to create and maintain a comfortable interior temperature. On average, the annual energy cost for cooling was about 36.7% per house. Several comparisons of energy use were made with minimal to moderate landscaping to determine the effectiveness of greening around the houses to reduce energy use in a tropical climate. Annual cooling energy savings reached up to 7%, equivalent to 948kWh (MYR233.00) per house. The results showed that landscaping had a significant impact on the cooling energy of the houses.
•Global warming potential and primary energy as impact categories are analyzed.•The case study demonstrated the total environmental impact.•The sources of CO2e emissions for this single-family house ...is investigated.•Using wood-based building materials result in low CO2e emissions.
To understand the reasons behind the large environmental impact from buildings the whole life cycle needs to be considered. Therefore, this study evaluates the carbon dioxide emissions in all stages of a single-family house in Sweden from the production of building materials, followed by construction and user stages until the end-of-life of the building in a life cycle assessment (LCA). The methodology applied is attributional life cycle assessment (LCA) based on ‘One Click LCA’ tool and a calculated life span of 100 years. Global warming potential (GWP) and primary energy (PE) are calculated by using specific data from the case study, furthermore the data regarding building materials are based on Environmental Product Declarations (EPDs). The results show that the selection of wood-based materials has a significantly lower impact on the carbon dioxide emissions in comparison with non-wood based materials. The total emissions for this single-family house in Sweden are 6 kg CO2e/m2/year. The production stage of building materials, including building systems and installations represent 30% of the total carbon dioxide equivalent emissions, while the maintenance and replacement part represents 37%. However, energy use during the in-use stage of the house recorded lower environmental impact (21%) due to the Swedish electricity mix that is mostly based on energy sources with low carbon dioxide emissions. The water consumption, construction and the end-of-life stages have shown minor contribution to the buildings total greenhouse gas (GHG) emissions (12%). The primary energy indicator shows the largest share in the operational phase of the house.
Biodiversity loss caused by housing is not a well-defined sector of environmental impact. This research quantifies effects on biodiversity of an average Spanish Single-Family House (SFH) with 180 m2 ...of built surface. The current Spanish SFH stock GWP amounts to 1.16 Gt CO2eq in a 50-year life cycle, 40 % of which is embodied in the building materials and the 60 % are emissions due to the use of the building. This stock also impacts with 10.2 Gt 1,4-DCB the land, water and human health. SFHs also drive 6052 species extinct in a 50 year life cycle, and account for 3.03 M years of life lost due to premature death or lived with a disability. Divided by the 16 M people living in Spanish SFHs, each one lost 0.19 years of their lives (68.1 days) due to their home's impacts on human health.
The article compares a reference conventional building against three low-impact cases, to understand how different building techniques and materials influence environmental outcomes that keep biodiversity loss the lowest possible. Scenarios include a standard brick and concrete house as Scenario 0 (SC0, Base), a timber Passivhaus as Scenario 1 (SC1), a straw-bale house with renewable energies as Scenario 2 (SC2), and an earth bioclimatic house as Scenario 3 (SC3). An initial Global Warming Potential (GWP) analysis was performed to relate previous building Life Cycle Assessment (LCA) studies with biodiversity metrics. Three main biodiversity metrics; ecotoxicity (as midpoint indicator), biodiversity loss and damage to human health (both as endpoint indicators) have been considered.
Compared to SC0 with 1292 kgCO2-eq·m−2 (516 embodied) of GWP, we found that SC1 emitted −47.0 % of that, SC2–41.4 % and SC3–80.9 %. Concerning ecotoxicity, where SC0 has 11,399 kg 1,4 DCB, the results are −27.9 % in SC1, −19.2 % in SC2, and −45.6 % in SC3. Regarding biodiversity loss, where SC0 has 7.54 E−06 species.yr·m−2, the impacts are −30.9 % in SC1, −32.6 % in SC2, and −58.6 % in SC3.
Human health damage in SC0 being 3.37 E−03 DALY, has been reduced in the timber home (SC1) is −44.2 %, of the Straw SFH (SC2) −39.2 %, and of the earth house (SC3) −67.1 %.
This article shows that with current existing technological solutions GWP could be reduced in −80.9 %, ecotoxicity in −45.6 %, biodiversity loss in −58.6 % and human health in −67.1 %. Spanish Single-Family Houses built in timber, earth or straw-bale are real alternatives to current cement traditional building.
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•Damage of single-family houses on biodiversity and human health is assessed in a 50 year lifecycle.•Terrestrial ecotoxicity midpoint impacts weight more than CO2eq emissions to the atmosphere.•Timber, straw, or rammed earth constructions cut impacts of conventional brick houses by half.•The Spanish stock of single-family houses drives yearly 6.052 species extinct in a 50 year lifecycle.
The use of wood and engineered wood products is today considered an opportunity for the mitigation of negative building environmental impacts, such as greenhouse gas emissions. However, the ...literature provides evidence that the quantification and generalization of the environmental benefits of wood during the whole building life cycle can be difficult. This paper presents a quantitative method based on Life Cycle Assessment (LCA) to compare, during their design stages, the environmental impacts produced by a timber-frame single-family house versus those of a concrete-masonry-based house built in Uruguay. The method, conceived as a decision-oriented tool, integrates Building Information Modelling (BIM) and LCA to quantify and compare the environmental impacts of one of the most common dwelling typologies in Uruguay. The results of the cradle-to-grave assessment show that the timber-frame building produced the lowest impacts in Global Warming Potential, Human Toxicity, Acidification Potential, Ozone Depletion Potential, and Freshwater Ecotoxicity, but yielded the highest impacts in Eutrophication Potential. The findings also show that the method developed herein facilitated the comparison and contrast between the pros and cons of both design options during their design stages.
In the architecture sector, single-family housing projects are often linked to demand from private clients, without arousing very much interest from developers, who seek higher returns on other real ...estate assets. For any owner, the construction of a home is perhaps the biggest investment of their life, and success or failure will therefore depend on the right decision. This paper presents a study of three different structural alternatives that are applied to a terraced house to facilitate decision making by a self-promoter, based on multiple criteria and taking sustainability into consideration. The methodology used allows us to identify the structure and to evaluate the different alternatives proposed here in order to find the optimal option. A comparison is drawn between a traditional reference solution, a pre-cast design and finally a technological option based on an integral reinforced concrete structural system. Although the technical feasibility of these last two solutions has been proven, they have not yet received enough attention from researchers to allow the thermal envelope of the building to be solved at the same time as the structure itself. The last of these alternatives achieved the best valuation, although it is neither the most widely used alternative or the quickest to build. This study demonstrates the practical versatility of a method that is seldom used in residential construction and only rarely used for single-family homes. We evaluate three alternatives for optimizing the structure and enveloping walls of a self-promoted, terraced house from a sustainability perspective. The study provides a set of indicators for assessing the environmental, economic and social aspects of a building throughout its life cycle. The sustainability index of the structural envelope obtained in this way allows a self-promoter to prioritize solutions to ensure its global sustainability.
•Each self-promoting decisions influence the global model of sustainable construction.•Self-construction prioritizes economic and functional aspects in the life cycle.•Three alternatives comparing traditional structure with non-conventional MMC systems.•A balance between the indicators favours a better sustainability index.•Reinforced concrete technology in housing reduces 10% lead times and 23% cost.
•We build a simulation model of a real high-performing French single-family house.•We define design options as parameters and create the related cost functions.•We set up a simulation-based method ...for minimizing the global cost function.•The more efficient the energy system, the more cost-impacting the envelope design.•The current French regulatory limits allow designing a cost-optimal building.
This study was developed in the context of new challenges imposed by the recast of the Energy Performance of Buildings Directive 2010/31/EU (EPBD) and its supplementing regulation. The aim is to find the cost-optimal level for the French single-family building typology, while providing an effective method to deal with a huge number of simulations corresponding to a large number of building configurations. The method combines the use of TRNSYS, dynamic energy simulation software, with GenOpt, Generic Optimization program.
The building that was taken as a reference is a real low-consumption house located in Amberieu-en-Bugey, Rhône-Alpes, France. The model was created and calibrated in TRNSYS and the energy efficiency measures, concerning different technologies for envelope systems and technical systems, were set up as parameters in GenOpt. After a research on the French market, a cost function was created for each parameter and the global cost function (EN15459 Standard) was taken as objective function for the optimization. The particle swarm optimization algorithm was used to minimize the objective function and find the cost-optimal building configuration within the current regulatory framework.
This paper presents a comparative analysis of the carbon footprint, energy demand and life cycle costs of a model of a building located in the Central Europe climate zone. One specific example—the ...quantitative differences in global warming potential, life cycle costs and thermal comfort—has been shown, depending on the different construction (wood, brick) and heat sources used; traditional and energy-saving solutions have been considered. The research was carried out using the EnergyPlus simulation program for a multi-zone model of a naturally ventilated single-family house. Calculations were made for a 25-year life cycle using the standard climate data for Warsaw (Poland). The real occupancy schedule of the individual rooms was adopted and the instantaneous ventilation airflow was modeled, and its intensification due to the additional opening of windows was optimized. An estimated budget of the entire structure of the building and the heat sources was used for the cost analysis. The research has succeeded in developing some general conclusions and guidelines and recommendations for both the investors and designers of energy-saving and environmentally friendly houses. Considering the most economical an ecological solution, wooden houses are better than brick houses. In the wooden building, however, there are a larger number of thermal discomfort hours.
Der Gebäudebestand benötigt rund 30 % des gesamten Endenergiebedarfes in Deutschland. Der Erfolg der Wärmewende hängt daher maßgeblich vom Einsparpotenzial im Gebäudebestand ab. Dazu gehört neben der ...Sanierung der Gebäudehülle auch der Einsatz einer klimaneutralen Wärmebereitstellung. Für dieses Ziel ist es vorteilhaft und notwendig, die Anlagentechnik von fossilen auf erneuerbare Energieträger umzurüsten. Derzeit gilt zu Recht die Wärmepumpe als Schlüsseltechnologie für das Gelingen der Wärmewende. Dieser Beitrag untersucht den Autarkiegrad der Kombination Wärmepumpe mit Photovoltaikanlage genauer. Um den Autarkiegrad bestimmen zu können, wird für ein konkretes Praxisbeispiel eine Simulationsrechnung mit dem Programm PV*SOL erstellt. Als maßgebend für die Auswertung wird der lastgerechte Autarkiegrad in Abhängigkeit der damit verbundenen Investitionskosten bestimmt und dargestellt.
Translation
Effects of replacing a gas heating system with an outdoor air heat pump in an EFH in terms of CO2 savings, self‐sufficiency and cost‐effectiveness
In Germany, existing buildings account for around 30 % of the total final energy demand. The success of the heating transition therefore depends on the saving potential in existing buildings. In addition to the refurbishment of the building envelope, this also includes the use of climate‐neutral heat supply. To achieve this goal, it is advantageous and necessary to convert the system technology from fossil fuels to renewable energy sources. At present, the heat pump is rightly regarded as the key technology for the success of the heating transition. This article analyses the degree of self‐sufficiency of the combination of heat pump and photovoltaic system in detail. In order to determine the degree of self‐sufficiency, an existing single‐family house as practical example has been analyzed using a building simulation by PV*SOL programme. The load‐based degree of self‐sufficiency is determined and presented as a function of the associated investment costs.
•Energy renovations of houses in moderate climates increase overheating risk.•Critical measures are the floor insulation and the improvement of the airtightness.•Decrease of the g value of windows ...diminishes the intensity and the period of it.•Static method of assessment shows higher risk compare to the dynamic method.•Ranking capabilities of overheating indices and average temperatures are analogous.
Many post-occupancy comfort studies of energy renovated residential buildings have documented elevated temperatures above comfort levels, not only during the summer period but also during the shoulder months. The main focus in renovation projects is on heat savings while the risk of overheating is not considered.
This paper analyze in which situations overheating and cooling need to be addressed in building energy renovation projects and which renovation measures are causing this need. The analysis contains four reference single family houses from central and northern Europe. Both dynamic and static methods were used to assess the overheating risk.
In terms of overheating occurrences, the most critical renovation measures are the insulation of the floor and the increase of the airtightness. The contribution of decreasing the g value of the window glazing is positive. The way to energy efficiency improvements also results in an extension of the overheating period and higher average and maximum building temperatures. The increase of the ventilation rates and the use of shading systems are useful measures for preventing overheating increase. The paper will highlight the inconsistencies which arise from the use of different criteria and also propose suggestions for future work.
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