35 results on '"Åsa Wahlström"'
Search Results
2. Uncertainty analysis of climate change potential assessments of five building energy renovation measures in Sweden
- Author
-
Karin Farsäter, Åsa Wahlström, and Dennis Johansson
- Subjects
Monte Carlo ,LCA ,Greenhouse gas emissions ,Refurbishment ,Energy efficiency ,LCI input data ,Science ,Technology - Abstract
Abstract The aim of this study is to assess the impact of the uncertainties of life cycle inventory (LCI) data for energy use and materials in life cycle assessments of standard energy renovation measures carried out in multi-family buildings in Sweden. Five energy renovation measures were assessed with regard to their climate change potential. Modules A1–A3 and module B6 were included in the assessment and the functional unit, 1 m2 heated floor area of a renovated building fulfilling the Swedish building regulations and with a calculation period of 20 years, was used. The uncertainty of LCI data for materials and energy were assessed using the Ecoinvent data quality system. This study shows that with two different energy mixes, all renovation measures result in a decrease in the climate change potential. The five renovation measures used in the simulations, with and without consideration to uncertainties, show a lower climate change potential when carried out than when not carried out. It is also shown in this study that the inclusion of the uncertainties of the input data did not have any impact on the overall decisions to renovate or not to renovate. However, this should not be regarded as a general conclusion. If a renovation measure were to have a higher level of material use, or if the “Future energy mix” were to be improved, uncertainty considerations could become much more important from a climate change perspective. Article Highlights All assessed energy renovation measures show a decrease in their climate change potential when carried out. The energy renovation measures with the largest decreases of climate change potential are also the measures with largest energy saving potential. When uncertainties are considered, there are no overlaps in the results when carrying out or not carrying out a renovation measure.
- Published
- 2021
- Full Text
- View/download PDF
3. Surviving through the kindness of strangers: can there be 'wellbeing' among undocumented refugee children?
- Author
-
Åsa Wahlström Smith
- Subjects
undocumented refugee children ,deportability ,wellbeing ,resilience ,anthropology ,Medicine (General) ,R5-920 - Abstract
Purpose: The paper exames notions of health and wellbeing in the context of radically retracted rights to political asylum. It questions the tendency in previous research to regard the political economy of refugee protection as a parallel issue to a range of factors affecting children’s health. Methods: Based on ethnographic research with 19 undocumented refugee children in Sweden, the paper illustrates ways in which the deportation regime conditions participants’ health. Results: Findings show that children lived with precarious status for the better part of their childhoods, alternating between undocumented and asylum seeking statuses. Participants accessed formal rights to education and health through complete or relative strangers at risk of exposure to authorities. The paper argues that conceptualisations of refugee children’s suffering in terms of risk and protective factors are redundant in this context. Moreover, deportability, protracted refugee situations and deprived material conditions are not unique to undocumented refugees, but characterise most refugee children’s lives in welfare states today. Conclusion: In relation to the plight of the refugee child, wellbeing seems to refer to an abstract ontology of desirable states of the human experience, far removed from the real day-to-day lives of individuals shaped by social suffering and structural violence.
- Published
- 2020
- Full Text
- View/download PDF
4. Learning from the outsiders-within: wearing the niqab in Swedish teacher profession and training
- Author
-
Hoda Fattali and Åsa Wahlström Smith
- Subjects
Cultural Studies ,Education ,Demography - Published
- 2023
- Full Text
- View/download PDF
5. Learning from the outsiders-within: wearing the niqab in Swedish teacher profession and training
- Author
-
Fattali, Hoda, primary and Smith, Åsa Wahlström, additional
- Published
- 2023
- Full Text
- View/download PDF
6. The impact of a DCV-system on the IAQ, energy use, and moisture safety in apartments - a case study
- Author
-
Åsa Wahlström, Akram Abdul Hamid, Victor Fransson, and Dennis Johansson
- Subjects
Apartment ,Moisture ,Indoor air ,0211 other engineering and technologies ,Environmental engineering ,02 engineering and technology ,Building and Construction ,law.invention ,Indoor air quality ,Control and Systems Engineering ,law ,021105 building & construction ,Ventilation (architecture) ,Environmental science ,021108 energy ,Electrical and Electronic Engineering ,Energy (signal processing) ,Civil and Structural Engineering - Abstract
A novel DCV-system controls the air-change rate for each apartment in multifamily buildings based on two indoor air parameters: 1) the moisture load (supply), and 2) volatile organic compounds. Wit...
- Published
- 2020
- Full Text
- View/download PDF
7. Challenging the deportation regime: reflections on the research encounter with undocumented refugee children in Sweden
- Author
-
Åsa Wahlström Smith
- Subjects
050906 social work ,Deportation ,Politics ,Sociology and Political Science ,Social Psychology ,Refugee ,Political science ,05 social sciences ,Geography, Planning and Development ,0507 social and economic geography ,0509 other social sciences ,Criminology ,050703 geography - Abstract
This article examines the researcher’s potential role and responsibility to facilitate undocumented refugee children’s political voice and participation. The paper raises issues of the social statu...
- Published
- 2020
- Full Text
- View/download PDF
8. Uncertainty analysis of climate change potential assessments of five building energy renovation measures in Sweden
- Author
-
Åsa Wahlström, Dennis Johansson, and Karin Farsäter
- Subjects
Technology ,Science ,General Chemical Engineering ,General Physics and Astronomy ,Climate change ,Unit (housing) ,Life cycle inventory ,Greenhouse gas emissions ,General Materials Science ,Monte Carlo ,Uncertainty analysis ,General Environmental Science ,Refurbishment ,Measure (data warehouse) ,LCA ,General Engineering ,Building energy ,Energy mix ,Environmental economics ,LCI input data ,Energy efficiency ,Data quality ,General Earth and Planetary Sciences ,Environmental science - Abstract
Abstract The aim of this study is to assess the impact of the uncertainties of life cycle inventory (LCI) data for energy use and materials in life cycle assessments of standard energy renovation measures carried out in multi-family buildings in Sweden. Five energy renovation measures were assessed with regard to their climate change potential. Modules A1–A3 and module B6 were included in the assessment and the functional unit, 1 m2 heated floor area of a renovated building fulfilling the Swedish building regulations and with a calculation period of 20 years, was used. The uncertainty of LCI data for materials and energy were assessed using the Ecoinvent data quality system. This study shows that with two different energy mixes, all renovation measures result in a decrease in the climate change potential. The five renovation measures used in the simulations, with and without consideration to uncertainties, show a lower climate change potential when carried out than when not carried out. It is also shown in this study that the inclusion of the uncertainties of the input data did not have any impact on the overall decisions to renovate or not to renovate. However, this should not be regarded as a general conclusion. If a renovation measure were to have a higher level of material use, or if the “Future energy mix” were to be improved, uncertainty considerations could become much more important from a climate change perspective. Article Highlights All assessed energy renovation measures show a decrease in their climate change potential when carried out. The energy renovation measures with the largest decreases of climate change potential are also the measures with largest energy saving potential. When uncertainties are considered, there are no overlaps in the results when carrying out or not carrying out a renovation measure.
- Published
- 2021
- Full Text
- View/download PDF
9. Additional requirement to the Swedish nearly zero energy requirements
- Author
-
Åsa Wahlström and Mari Liis Maripuu
- Subjects
lcsh:GE1-350 ,Primary energy ,Occupancy ,Apartment ,Work (electrical) ,Order (exchange) ,Computer science ,Environmental economics ,Discount points ,Building envelope ,Energy (signal processing) ,lcsh:Environmental sciences - Abstract
This study has analysed which options would be appropriate to use as additional requirements to the main requirement of primary energy number in the new Swedish building regulations. The starting point is to ensure that buildings are built with good qualitative properties in terms of the building envelope so that low energy use can be maintained throughout the life of the building despite changes in installation systems or the building’s occupancy. The additional requirements should aim to minimize energy losses, i.e., to ensure that the building's total energy demand is low. The following possible additional requirements have been examined: net energy demand, net energy demand for heating, heat power demand, heat loss rate and average heat transfer coefficient. In order to ensure that the additional requirements will work as desired and to explore possibilities with, and identify the consequences of, the various proposals, calculations have been made for four different categories of buildings: single-family houses, apartment buildings, schools and offices. The results show that the suggested option net energy demand will not contribute to any additional benefits in relation to primary energy number. The other options analysed have both advantages and disadvantages and it is difficult to find a single additional requirement that fulfils all the pre-set demands.
- Published
- 2021
10. Literature review on renovation of multifamily buildings in temperate climate conditions
- Author
-
Petter Wallentén, Karin Farsäter, Åsa Wahlström, and Akram Abdul Hamid
- Subjects
Engineering ,Architectural engineering ,business.industry ,Process (engineering) ,020209 energy ,Mechanical Engineering ,02 engineering and technology ,Building and Construction ,010501 environmental sciences ,01 natural sciences ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,business ,0105 earth and related environmental sciences ,Civil and Structural Engineering - Abstract
In Sweden, approximately 1.4 million dwellings were built 1946–1975. Today, a considerable part of these are in need of renovation for various reasons. Research results, as well as experiences and outcomes from renovation projects could facilitate in performing more efficient renovations. As an aid for further research, this paper aims to compile and review relevant literature that may support in choosing a renovation strategy as well as decisions on renovation measures. The focus of this paper is research on status determinations, renovation strategies and renovation measures. Differences and similarities within these areas are presented through the analysis of 234 relevant references. The results show that renovation of multifamily buildings in temperate climate conditions is widely researched. The included research has a strong energy focus, and while other aspects of renovation are researched as well, they are not as strongly represented. Status determinations are often based on data from national databases that include useful information that could help alleviate decision making in the renovation process. This study suggests that future research should be conducted on the effect of such databases on the renovation process. This study also shows that there are numerous renovation strategies, and while there are both in-depth and broader strategies, these are seldom connected. Finally, there are many references evaluating various effects of the application of renovation measures, but some effects and measures are more widely researched than others. This study lays a strong foundation for further in-depth research on the reviewed articles, reports, and theses.
- Published
- 2018
- Full Text
- View/download PDF
11. ‘Hiding in Plain Sight’: Daily Strategies and Fear Management among Undocumented Refugee Children in Sweden
- Author
-
Åsa Wahlström Smith
- Subjects
Sight ,Political science ,Refugee ,05 social sciences ,Political Science and International Relations ,Geography, Planning and Development ,050602 political science & public administration ,0507 social and economic geography ,Criminology ,050703 geography ,0506 political science - Published
- 2018
- Full Text
- View/download PDF
12. Surviving through the kindness of strangers: can there be “wellbeing” among undocumented refugee children?
- Author
-
Smith, Åsa Wahlström, primary
- Published
- 2020
- Full Text
- View/download PDF
13. Challenging the deportation regime: reflections on the research encounter with undocumented refugee children in Sweden
- Author
-
Smith, Åsa Wahlström, primary
- Published
- 2020
- Full Text
- View/download PDF
14. Cold Climate HVAC 2018 : Sustainable Buildings in Cold Climates
- Author
-
Dennis Johansson, Hans Bagge, Åsa Wahlström, Dennis Johansson, Hans Bagge, and Åsa Wahlström
- Subjects
- Heating--Congresses, Sustainable buildings--Congresses
- Abstract
This volume presents the proceedings of the 9th Cold Climate HVAC conference, which was held in Kiruna, Sweden in 2018. The conference highlighted key technologies and processes that allow scientists, designers, engineers, manufacturers and other decision makers in cold climate regions to achieve good indoor environmental quality (IEQ) with a minimum use of energy and other resources. The conference addressed various technical, economic and social aspects of buildings and HVAC systems in new and renovated buildings. This proceedings volume gathers peer-reviewed papers by a diverse and international range of authors and showcases perspectives and practices in cold climate building design from around the globe. The following major aspects, which include both fundamental and theoretical research as well as applications and case studies, are covered: (1) Energy and power efficiency and low-energy buildings; (2) Renovatingbuildings; (3) Efficient HVAC components; (4) Heat pumps and geothermal systems; (5) Municipal and city energy systems; (6) Construction management; (7) Buildings in operation; (8) Building simulation; (9) Reference data; (10) Transdisciplinary connections and social aspects; (11) Indoor environments and health; (12) Moisture safety and water damage; (13) Codes, regulations, standards and policies; and (14) Other aspects of buildings in cold climates.
- Published
- 2019
15. A certification scheme for operation of buildings with well-planned and ambitious environmental improvements
- Author
-
Åsa Wahlström and Catarina Warfvinge
- Subjects
Identification (information) ,Presentation ,Architectural engineering ,Work (electrical) ,Order (business) ,Effects of global warming ,media_common.quotation_subject ,Environmental certification ,Business ,Certification ,Environmental quality ,media_common - Abstract
The development of environmental certification schemes has increased rapidly during the last twenty years and are often used as benchmarks during design of new buildings or reconstruction. However, for management of our existing buildings the members of Sweden Green Building Council request for clear guidelines and a certification scheme. Therefore, a new certification scheme called Miljöbyggnad in Operation has been developed within close cooperation with branch actors through interviews, workshops and suggestions for consideration. The scheme will be launched in summer 2020. The new scheme act as a guidance tool for the property sector to meet the environmental quality objectives. Today many of our existing buildings do not even meet the requirements within the Swedish Environmental Code and many tenants are suffering with health problems due too low indoor environment qualities in their homes, in schools or at work. Therefore, high focus is on indoor environment and occurrence of dangerous substances but also aspects that consider improved health. Use of energy and resources are considered to reduce the impact of global warming. Building’s status is evaluated in order to make deliberate environmental improvements. Eighteen environmental aspects are assessed with about 250 statements that should be answered with yes in order to give one score. With the scores the building owner will get a good identification of the worst parts of the building and which measures that directly will give substantial results. The aim is to give a clear presentation of the building’s status, irrespective of building category or age, and to inspire for a well-planned and ambitious environmental improvement with gamification.
- Published
- 2020
- Full Text
- View/download PDF
16. Not even close to the goals - A 'snapshot' of Swedish property owners’ energy renovation plans
- Author
-
Åsa Wahlström and Karin Glader
- Subjects
business.industry ,Energy agency ,Interview study ,Snapshot (computer storage) ,Business ,Electricity ,Environmental economics ,Efficient energy use ,Swedish government - Abstract
A pre-requisite to reach the EU 2030 and beyond targets is a significantly increased ambition among property owners regarding energy-efficient refurbishments. The Swedish Energy Agency and the National Board of Housing, Building and Planning are on the Swedish government assignment developing a strategy with policy instruments to increase energy-efficiency oriented renovation. In order to design the right policy instruments, deeper knowledge is needed on the potential for energy efficiency and property owners’ present actions. To gain more insight into these questions an interview study with 20 building owners, covering more than 15% of the Swedish property area of multi-family buildings, schools and offices were performed in 2016. The interviews aimed to identify how building owners reason on different energy saving levels, what level of energy efficiency they currently are realizing and what obstacles and possibilities they expect if they take further steps in energy renovation. The interviews were based on four different common packages of energy-efficiency measures defined as renovations levels: 4, 15, 30, and 50 percent respectively. In 2019 the strategy was updated based on follow up interviews with mainly the same building owners. The interview results were used, together with assumptions of future renovation rates, in a calculation tool called HEFTIG. This tool enables long term calculation and visualization of energy-efficiency measures. The present situation was compared with scenarios made in 2016 and new scenarios were developed for 2030, 2040 and 2050 for the Swedish building stock. The result is a “snapshot” is that the property owners’ current actions are far from the cost-efficient potential and that the potential is larger for heating than for electricity. The results also show that the energy renovation rate has to increase in the near future if the EU targets should be reached.
- Published
- 2020
- Full Text
- View/download PDF
17. Guidelines with routines and documentation for handling energy requirements within the building process
- Author
-
Birgitta Govén, Åsa Wahlström, Victoria Edenhofer, and Andreas Hagnell
- Subjects
Architectural engineering ,Documentation ,Computer science ,Building process ,Energy performance ,Plan (drawing) ,Guideline ,Directive ,Energy requirement - Abstract
As a result of the energy performance of the buildings directive (EPBD 2010), the requirements have been gradually tightened in the Swedish building regulations. For the purpose of the directive to be realized, it is becoming increasingly important to ensure that buildings actually live up to the minimum rules laid down in the Swedish Building Regulations (BBR) or more ambitious requirements imposed directly by the clients. To gain more insight into these questions, today´s building process has been studied through interviews and workshops with regional actors in seven regions around Sweden. A guideline is proposed with new routines and documentation for the building process, i.e. handling of starting clearance, designing of inspection plan and follow-up for final clearance.
- Published
- 2020
- Full Text
- View/download PDF
18. Needs of Support for Swedish Property Owners to Implement More Energy-Efficiency Improvements During Renovations
- Author
-
Åsa Wahlström
- Subjects
Incentive ,Subsidy ,Business ,Environmental economics ,Built environment ,Stock (geology) ,Efficient energy use - Abstract
It is a well-known fact that the built environment in Europe is responsible for approximately 40% of the overall energy end usage and that this has to be reduced drastically for the building stock to be sustainable in the long term. A prerequisite to meet the EU 2020 and 2030 targets is significantly increased ambition among property owners regarding energy-efficient renovation. However, it is not easy to regulate that large-scale energy-efficiency measures should be included in the ordinary renovation of buildings. In order to design the right policy instruments to influence property owners towards energy-efficiency-oriented renovation, deeper knowledge is needed on how property owners act and argue today. This study reviews several recently performed studies with the aim of obtaining an overview of how the decision-making process is conducted, and it makes comparisons between different categories of buildings. The aim is to allow conclusions to be drawn on whether a financial incentive is important to bringing about energy-efficiency renovation and, if so, how such an incentive should be formulated. The study shows that direct and simple subsidies are needed to bring about major energy-efficiency improvements in housing in connection with renovations, especially when it comes to additional insulation for facades. For non-residential property, there is little need for financial support, while other forms of support are needed. Current energy-efficiency improvements in connection with renovations are modest and a long way off the technical potential.
- Published
- 2018
- Full Text
- View/download PDF
19. Criteria for Sustainable Buildings in Sweden
- Author
-
Åsa Wahlström and Catarina Warfvinge
- Subjects
Architectural engineering ,Documentation ,Work (electrical) ,business.industry ,Certification ,Best available technology ,Building design ,business ,Environmental quality ,Renewable energy ,Efficient energy use - Abstract
To continue to be an effective guidance tool for the property and construction sectors and to meet the environmental quality objectives, the Swedish certification system Miljobyggnad needed to be developed. Over the years, new research results have been published and political decisions made that affect sustainable building and construction. What was rated as ‘best available technology’ ten years ago has now become standard. In this project, industry and academia have collaborated to implement research findings into practice. Miljobyggnad considers requirements of energy, indoor environment and material use. The criteria give high scores for low heating power need, low heating loads from the sun, energy efficiency, high share of renewable energy, good sound levels, low radon exposure, good ventilation performance, moisture safety, indoor comfort in winter and summer, good daylight, low risk of legionella, documentation on material used, avoidance of hazardous substances and evaluation of the framework’s life cycle effects on climate change. Compliance with the criteria in Miljobyggnad improves the potential for sustainable building design. The criteria give special consideration to fitting in with the outdoor climate throughout Sweden as well as Swedish building regulations and practice in the property and construction sectors. The work to evaluate and improve the criteria in Miljobyggnad has taken two years and involved over 250 people from research and industry. The criteria are based on scientific values and can be verified, and they all support meeting different environmental objectives.
- Published
- 2018
- Full Text
- View/download PDF
20. Challenging the deportation regime: reflections on the research encounter with undocumented refugee children in Sweden.
- Author
-
Smith, Åsa Wahlström
- Subjects
- *
UNDOCUMENTED immigrant children , *REFUGEE children , *SOCIAL status , *CHILDREN'S rights , *POLITICAL participation - Abstract
This article examines the researcher's potential role and responsibility to facilitate undocumented refugee children's political voice and participation. The paper raises issues of the social status and position scholars give to children in research and epistemological concerns regarding the co-production of children's political assertions in the research encounter. Based on anthropological and participatory research with undocumented refugee children, the article shows that children were often withholding their suffering from family members and it was novel for children to talk openly about their situations with the researcher. However, as trusting relationships developed, children came to formulate and express a social critique of their undocumented situations. Based on children's accounts, the research project engaged with a range of public actors to promote critical dialogue around these children and contribute to societal practice. It is argued that children's lived rights and politics are properly acknowledged when researchers facilitate children's political engagements. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
21. Defrosting and Frost Protection Measurements of Heat Recovery in Cold Climate
- Author
-
Dennis Johansson, Åsa Wahlström, and Mats Dahlblom
- Subjects
Work (thermodynamics) ,Moisture ,business.industry ,law.invention ,Defrosting ,law ,Heat recovery ventilation ,Ventilation (architecture) ,Heat exchanger ,Environmental science ,Frost (temperature) ,Process engineering ,business ,Efficient energy use - Abstract
The installation of technical solutions for heat recovery from the ventilation air is a very important step, both with respect to improving the indoor climate and as an energy-saving measure. Ventilation without heat recovery use a substantial part of an entire building’s heating use, especially if the building is a low energy building. To realize a large implementation of heat recovery property owners must increase their knowledge about how these systems work and they must be able to rely on them functioning properly. The function and performance of a ventilation system when it comes to heat recovery can be a problem as soon as temperatures drop far below zero. When freezing occurs some form of defrosting is required and this can lead to indoor climate problems and to little or no heat recovery being obtained, which will reduce the energy efficiency and, at the same time, may compromise moisture safety. The goal of this project is to increase knowledge about how heat recovery systems for residential buildings with respect to defrosting and frost protection measures in heat exchangers. The knowledge can thereafter be used to develop effective defrosting strategies and frost protection measures so that the energy use and power requirements are minimized. Measurements were performed for heat recovery systems placed in dwellings in north Sweden to investigate occurrence of frost formation. The paper will present these measurements and some comparing simulations which can serve as a basis for further development of good defrosting strategies.
- Published
- 2019
- Full Text
- View/download PDF
22. Building status obtained before renovating multifamily buildings in Sweden
- Author
-
Karin Farsäter, Paulien Strandberg, and Åsa Wahlström
- Subjects
Architectural engineering ,Engineering ,Process (engineering) ,business.industry ,0211 other engineering and technologies ,02 engineering and technology ,Building and Construction ,Building engineering physics ,Status assessment ,Documentation ,Mechanics of Materials ,021105 building & construction ,Architecture ,021108 energy ,Decision process ,Safety, Risk, Reliability and Quality ,business ,Civil and Structural Engineering - Abstract
The aim of this study was to analyse how energy use, building physics properties and indoor environment data have been obtained in the initial evaluation phases of multifamily building renovations in Sweden. Between 1964 and 1975, approximately one million homes were built in Sweden. These buildings are now in need of renovation. To perform proper status assessment of a building before a renovation is important both to make decisions on renovation measures on correct information as well as to be able to perform follow-ups of renovation projects. The analyses in this study was performed with questionnaires in eight case studies. Studied data included energy use, building physics properties and indoor environmental factors. The study shows that information about a building's status, and the subsequent renovation process, is often linked to one or just a few people involved in the project without any systematic documentation. When they leave their employment, due to changing jobs or retirement, documentation about the condition of the building, material choices and decision processes is often lost.
- Published
- 2019
- Full Text
- View/download PDF
23. Decision Making Process for Constructing Low-Energy Buildings in the Public Housing Sector in Sweden
- Author
-
Åsa Wahlström, Josefin Florell, Björn Berggren, Thomas Sundén, and Rickard Nygren
- Subjects
leadership ,Engineering ,interviews ,Public housing ,media_common.quotation_subject ,Geography, Planning and Development ,TJ807-830 ,decision making process ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,new construction ,TD194-195 ,01 natural sciences ,Renewable energy sources ,Transport engineering ,Low energy ,0502 economics and business ,GE1-350 ,Quality (business) ,Decision-making ,Built environment ,0105 earth and related environmental sciences ,media_common ,Finance ,low-energy buildings ,Environmental effects of industries and plants ,Renewable Energy, Sustainability and the Environment ,business.industry ,05 social sciences ,Energy consumption ,Environmental sciences ,Scale (social sciences) ,business ,050203 business & management ,Efficient energy use - Abstract
The built environment accounts for a significant share of energy consumption and energy efficiency in this sector is important for the Swedish environmental objectives. Only a limited share of the total new construction of multifamily houses are constructed as low-energy buildings. Current building regulations lay down requirements for energy efficiency for new construction, and these will be tightened further in the future. Public housing companies often aim to be at the forefront, and the public housing sector has now built half of Sweden’s low-energy blocks of flats. Many public housing companies have tried, but it is uncertain if they will, or have, the possibilities to construct low-energy buildings on a large scale. Twenty public housing companies around Sweden have been interviewed with the aim of identifying obstacles and possibilities to be forerunners and build better than required by the building regulations. The study shows that the public housing companies build better than the law demands and intend to continue doing so. Low-energy buildings are particularly suitable in central locations where land is attractive and the required returns lower. The driving motivation is to be at the forefront and to build green. The new pressure to increase house building can lead to a risk of energy and quality issues being passed over. For the increase in the construction of low-energy buildings to continue, extended, shared and comparable decision making support for the public housing companies is needed.
- Published
- 2016
- Full Text
- View/download PDF
24. Fed-batch production of recombinant β-galactosidase using the universal stress promotersuspAanduspBin high cell density cultivations
- Author
-
Anne Farewell, Cecilia Förberg, Åsa Wahlström, Anna Maria Sandén, Ingela Prytz, Colin R. Harwood, Zoltán Prágai, Thomas Nyström, Gen Larsson, and Michael R. Barer
- Subjects
chemistry.chemical_classification ,biology ,Substrate (chemistry) ,Bioengineering ,Promoter ,biology.organism_classification ,medicine.disease_cause ,Applied Microbiology and Biotechnology ,Enterobacteriaceae ,Guanosine Tetraphosphate ,law.invention ,Enzyme ,chemistry ,Biochemistry ,law ,medicine ,Recombinant DNA ,Escherichia coli ,Biotechnology ,Alarmone - Abstract
A high-level production system using the universal stress promoters uspA and uspB in a fed-batch cultivation based on minimal medium was designed. In development it was shown that a standard industrial fed-batch protocol could not be used for this purpose since it failed to induce the levels of product as compared to the basal level. Instead, a batch protocol followed by a low constant feed of glucose was shown to give full induction. The levels of the product protein, beta-galactosidase, corresponded to approximately 25% of the total protein. Higher levels were found using the uspA than uspB vectors where uspA showed considerably higher basal level. The data indicate that the sigma(70) regulated promoter, uspA, although affected by the alarmone guanosine tetraphosphate, ppGpp, worked partly in a similar manner to constitutive promoters. An industrial high cell density fed-batch cultivation on the basis of the suggested fed-batch protocol and the uspA promoter gave a final beta-galatosidase concentration of 7 g/L and a final cell concentration of 65 g/L. The heterogeneity in production of the individual cell was measured by fluorescence microscopy. The data show that there is a process time independent heterogeneity in production, which is suggested to be caused by heterogeneity in the substrate uptake rate of the individual cell.
- Published
- 2003
- Full Text
- View/download PDF
25. Development of models for prediction of solubility for HFC working fluids in pentaerythritol ester compressor oils
- Author
-
Åsa Wahlström and Lennart Vamling
- Subjects
Materials science ,Mechanical Engineering ,Relative standard deviation ,Thermodynamics ,Building and Construction ,Pentaerythritol ,Activity factor ,Refrigerant ,chemistry.chemical_compound ,chemistry ,Solubility ,Lubricant ,Gas compressor ,UNIFAC - Abstract
This study aims to further develop a model of the group contribution type that can predict the solubility of mixtures of HFC working fluids and pentaerythritol ester compressor oils. The investigation is based on solubility data for 20 systems of five different HFCs in four different pentaerythritol esters. First, five different activity factor-based thermodynamic models were investigated to determine to what extent they can describe the solubility data. Two promising models were selected and extended with group contribution parameters to be able to predict solubility data. The first model, a modified Flory–Huggins based predictive model (termed MFH), needs only 15 general parameters to describe the data with a relative deviation of less than 3.4%. The second model, a predictive Unifac model with an extended temperature dependence, needs 33 general parameters to describe the solubility data for the 20 systems with a relative deviation of less than 3.5%.
- Published
- 2000
- Full Text
- View/download PDF
26. Solubility of HFC32, HFC125, HFC134a, HFC143a, and HFC152a in a Pentaerythritol Tetrapentanoate Ester
- Author
-
Lennart Vamling and Åsa Wahlström
- Subjects
Refrigerant ,chemistry.chemical_compound ,chemistry ,General Chemical Engineering ,Organic chemistry ,Compatibility (geochemistry) ,General Chemistry ,Binary system ,Fluorocarbon ,Solubility ,Pentaerythritol ,Coolant - Abstract
Solubilities of five different hydrofluorocarbons (HFCs) in a pentaerythritol tetrapentanoate ester (95% purity) have been measured at temperatures between 303.15 and 363.15 K and pressures between...
- Published
- 1999
- Full Text
- View/download PDF
27. A Cubic Equation of State with Group Contributions for the Calculation of Vapor−Liquid Equilibria of Mixtures of Hydrofluorocarbons and Lubricant Oils
- Author
-
Alberto Bertucco, Nicola Elvassore, and Åsa Wahlström
- Subjects
Activity coefficient ,UNIQUAC ,Chemistry ,Vapor pressure ,General Chemical Engineering ,Thermodynamics ,General Chemistry ,Hexadecane ,Pentaerythritol ,Industrial and Manufacturing Engineering ,Group contribution method ,Refrigerant ,chemistry.chemical_compound ,Volume (thermodynamics) - Abstract
A method for calculating the vapor−liquid equilibria of mixtures between hydrofluorocarbons and lubricant oils is presented. A cubic equation of state is used (Sako, T.; et al. J. Appl. Polym. Sci. 1989, 38, 1839), containing three parameters: the attractive one, a, the volume parameter, b, and the number of external degrees of freedom per molecule, c. To allow calculation of the parameters of the high molecular weight components, whose critical constants and vapor pressure are unknown, a group-contribution approach is developed for a, b, and c. The extension to mixtures is achieved by applying Huron−Vidal mixing rules. A modified Uniquac model is used to evaluate infinite-pressure activity coefficients. With the proposed method, the density of pure heavy components (such as n-hexadecane and pentaerythritol esters) is predicted as a function of temperature. Vapor−liquid equilibria calculations are presented for binary mixtures between several hydrofluorocarbons and pentaerythritol esters or hexadecane; a...
- Published
- 1999
- Full Text
- View/download PDF
28. The solubility ofHFC125,HFC134a,HFC143a andHFC152a inn-eicosane,n-hexadecane,n-tridecane and 2, 6, 10, 14-tetramethylpentadecane
- Author
-
Åsa Wahlström and Lennart Vamling
- Subjects
N-tridecane ,Thermodynamic model ,Activity coefficient ,chemistry.chemical_compound ,UNIQUAC ,Chemistry ,General Chemical Engineering ,High pressure ,N-hexadecane ,Tridecane ,Analytical chemistry ,Thermodynamics ,Solubility - Abstract
The solubility of 1, 1, 1, 2,2-pentafluoroethane (HFC125), 1, 1, 1, 2-tetrafluoroethane (HFC134a), 1, 1, 1-trifluoroethane (HFC143a) and 1,1-difluoroethane (HFC152a) in four well-known hydrocarbons have been measured at temperatures between 293.15 and 363.15 K and pressures between 0.05 and 2 MPa. Henry's constant, and the activity coefficient for HFCs at infinite dilution, have been derived for measurements below 0.28 MPa. The measurements were made with an isochoric method and their uncertainty is less than 2% for Henry's constant and less than 3% at high pressure. For several mixtures, the experimental data have been correlated with the UNIQUAC method and binary interaction parameters have been derived, resulting in a deviation from the data of less than 4%. La solubilite de 1, 1, 1, 2, 2-pentafluoroethane (HFC125), de 1, 1, 1, 2-tetrafluorethane (HFC134a), de 1, 1, 1-trifluoroethane (HFC143a) et de 1, 1-difluorethane (HFC152a) dans quatre hydrocarbures bien connus a ete mesuree e des temperatures entre 293,15 et 363,15 K et des pressions entre 0,05 et 2 MPa. La constante de Henry et le coefficient d'activite pour les HFC e une dilution infinie ont ete calcules pour les mesures effectuees en-dessous de 0,28 MPa. Les mesures ont ete realisees avec une methode isovolumique et leur incertitude est inferieure e 2% pour la constante de Henry et inferieure e 3% e une pression elevee. Pour plusieurs melanges, les donnees experimentales ont ete correlees avec la methode UNIQUAC et des parametres d'interaction binaire ont ete calcules, montrant un ecart avec les donnees de moins de 4%.
- Published
- 1997
- Full Text
- View/download PDF
29. Prediction of solubility forHFCworking fluids in model substances for compressor oils
- Author
-
Lennart Vamling and Åsa Wahlström
- Subjects
Thermodynamic model ,UNIQUAC ,Chemistry ,General Chemical Engineering ,Thermodynamics ,Solubility ,UNIFAC - Abstract
This study is a first step towards the prediction of the behaviour of working fluids and compressor oils. Different thermodynamic models are investigated and a modified Flory-Huggins-based predictive model, termed MFH, is proposed for solubility of HFCs in long-chained hydrocarbons. From experimental data, 7 general parameters have been fitted for the MFH model to describe 14 binary systems. The UNIQUAC model demands 28 specific parameters without the possibility of extending their validity to other mixtures. A predictive UNIFAC model requires 8 general parameters, but its uncertainty, 17%. is poor compared to the MFH model's 7%. Cette etude est une premiere etape vers la prediction du comportement de fluides hydrauliques et d'huiles de compresseur. Differents modeles thermodynamiques sont etudies et un modele predictif de Flory-Huggins modifie, appele MFH, est propose pour la solubilite des HFC dans des hydrocarbures a chaine longue. A partir de donnees experimentales, 7 parametres generaux ont ete cales dans le modele MFH afin de decrire 14 systemes binaires. Le modele UNIQUAC exige 28 parametres specifiques sans possibilite d'etendre leur validite a d'autres melanges. Un modele predictif UNIFAC requiert 8 parametres generaux, mais son incertitude, 17%, est mauvaise comparativement aux 7% du modele MFH.
- Published
- 1997
- Full Text
- View/download PDF
30. 'Hiding in Plain Sight': Daily Strategies and Fear Management among Undocumented Refugee Children in Sweden.
- Author
-
Smith, Åsa Wahlström
- Subjects
- *
POLITICAL refugees , *EDUCATION , *HEALTH , *EMIGRATION & immigration , *REFUGEE children - Abstract
Undocumented refugee children live a paradoxical existence, excluded from the right to remain in Sweden while at the same time holding formal rights to education and health. Building on long-term ethnographic research with 19 undocumented children aged 6 to 17, my analysis shows that children carry a pivotal role in hiding their own and the family's whereabouts and migration status. The concept of invisibility is used to explain the political and social forces at play in relation to which undocumented refugee children attempt to hide 'in plain sight'. To maintain social invisibility, I suggest, children must work out whom to reveal their undocumented refugee status to, in both close and distant social relationships. The issue of undocumented migrant children's access to human rights within the local authority is discussed, as well as children's active role in contributing to and transforming the undocumented migration situation. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
31. Present Energy Performance Requirements and nZEB Targets in Some Selected Countries
- Author
-
Karsten Voss, Per Heiselberg, Christian Feldmann, Jarek Kurnitski, Åsa Wahlström, Igor Sartori, and Livio Mazzarella
- Subjects
Moment (mathematics) ,Primary energy ,Work (electrical) ,Member states ,Energy performance ,Comparison results ,Harmonization ,Business ,Plan (drawing) ,Environmental economics - Abstract
At the moment, there are already some official definitions of nZEBs available at least in Denmark, Estonia, and France, but most of the Member States intensively work with national definitions and plan for nZEBs. In the following, the situation in some selected countries is reported. At the end of the chapter, the issue of comparison of national requirements is discussed and comparison results of some countries based on the data of January 2013 are shown. Some harmonization in minimum energy performance requirements can be seen.
- Published
- 2013
- Full Text
- View/download PDF
32. Fed-batch production of recombinant β-galactosidase using the universal stress promoters uspA and uspB in high cell density cultivations.
- Author
-
Ingela Prytz, Anna Maria Sandén, Thomas Nyström, Anne Farewell, Åsa Wahlström, Cecilia Förberg, Zoltan Pragai, Mike Barer, Colin Harwood, and Gen Larsson
- Subjects
PROMOTERS (Genetics) ,GLUCOSE ,PROTEINS ,CELLS ,FLUORESCENCE microscopy - Abstract
A high-level production system using the universal stress promoters uspA and uspB in a fed-batch cultivation based on minimal medium was designed. In development it was shown that a standard industrial fed-batch protocol could not be used for this purpose since it failed to induce the levels of product as compared to the basal level. Instead, a batch protocol followed by a low constant feed of glucose was shown to give full induction. The levels of the product protein, β-galactosidase, corresponded to approximately 25% of the total protein. Higher levels were found using the uspA than uspB vectors where uspA showed considerably higher basal level. The data indicate that the σ
70 regulated promoter, uspA, although affected by the alarmone guanosine tetraphosphate, ppGpp, worked partly in a similar manner to constitutive promoters. An industrial high cell density fed-batch cultivation on the basis of the suggested fed-batch protocol and the uspA promoter gave a final β-galatosidase concentration of 7 g/L and a final cell concentration of 65 g/L. The heterogeneity in production of the individual cell was measured by fluorescence microscopy. The data show that there is a process time independent heterogeneity in production, which is suggested to be caused by heterogeneity in the substrate uptake rate of the individual cell. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 595603, 2003. [ABSTRACT FROM AUTHOR]- Published
- 2003
- Full Text
- View/download PDF
33. Evaluation of a Low-energy Residence for Users with Functional Disorders
- Author
-
Åsa Wahlström, Ann Marie Ejlertsson, and Dennis Johansson
- Subjects
Architectural engineering ,Engineering ,business.industry ,Project commissioning ,Energy performance ,General Medicine ,indoor climate ,passive house ,Low energy ,HVAC ,Residence ,disabled user ,Passive house ,business ,Engineering(all) - Abstract
A building for users with functional disorders has been built with the aim of being a low-energy residence, based on the criteria and technology applicable to passive houses. This new application of the passive house concept in a Nordic climate has shown that challenges must be met when producing buildings with a low energy demand while also fulfilling the requirements for a good indoor climate. The residents in this building have higher comfort demands than normal, which in turn may have an influence on the energy use. An evaluation of both the energy performance and indoor comfort was carried out over a period of nearly two years after commissioning the HVAC systems. The results show that the building's energy performance meets the requirements set by the local municipality, which were 30% stricter than the Swedish building regulations, and the indoor climate was deemed acceptable.
- Full Text
- View/download PDF
34. Nordic Market for Climate Friendly Buildings - Status, Barriers and Opportunities
- Author
-
Inger Andresen, Kirsten Engelund Thomsen, and Åsa Wahlström
35. Solubility of HFCs in pentaerythritol tetraalkyl esters
- Author
-
Åsa Wahlström and Lennart Vamling
- Subjects
Activity coefficient ,chemistry.chemical_compound ,chemistry ,Isochoric process ,General Chemical Engineering ,Thermodynamics ,General Chemistry ,Binary system ,Fluorocarbon ,Solubility ,Difluoromethane ,Pentaerythritol ,Dilution - Abstract
The solubilities of difluoromethane (HFC32), 1,1,1,2,2-pentafluoroethane (HFC125), 1,1,1,2-tetrafluoroethane (HFC134a), 1,1,1-trifluoroethane (HFC143a), and 1,1-difluoroethane (HFC152a) in pentaerythritol tetranonanoate, pentaerythritol tetra-2-ethylbutanoate, and pentaerythritol tetra-2-ethylhexanoate have been measured at temperatures between 303 and 363 K and pressures between 0.07 and 2.1 MPa. Henry's constant and the activity coefficient for HFCs at infinite dilution were derived for measurements below 0.34 MPa. The measurements were made by an isochoric method with an uncertainty of HFC134a > HFC32 > HFC125 > HFC143a. The experimental data have been correlated with a Flory−Huggins model with an extended temperature dependence, which is able to describe the data with a deviation from measured data of
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.