211 research outputs found
The Climate Dimension in the Design of Resilient Urban Neighborhoods in Norway: A study on materials, outdoor thermal comfort, and building energy demand in the context of the urban microclimate
No full textOne of the 17 Sustainable Development Goals proclaimed in the 2030 Agenda for Sustainable Development by the United Nations is Sustainable Cities and Communities. In the view of urbanization and a rising world population, the ambition is to create and transform cities into climate-resilient, safe, healthy, climate-friendly, and livable environments for its citizens. This thesis aims to contribute to this goal in the context of Norwegian climate conditions. For that, multiple approaches and methodologies are used.
First, an extensive literature study is conducted to synthesize the characteristics of the urban climate, focus areas, and research gaps from scientific publications addressing cold and polar climate regions. Second, numerical tools including computational fluid dynamics (CFD) and building performance simulation (BPS) are used to create models for studying the effect of different climates and design scenarios particularly with regard to people’s outdoor thermal comfort and building energy demand. Field measurements of relevant climate variables from a network of fixed and temporary weather stations are used to provide input and validation data for the numerical models predicting the local climate conditions in an urban neighborhood (microclimate). Finally, a coupling methodology for CFD and BPS is presented that allows investigation of the energy demand of different floors of a high-rise building considering vertical temperature gradients derived from CFD simulations. For most of the thesis work, the Gløshaugen campus of the Norwegian University of Science and Technology which is currently under redevelopment served as a case study.
From the literature review, it was found that the urban climate in cold climate regions is strongly affected by the presence of the urban heat island (UHI). Mostly, observational methods were used and only 22 % of the reviewed studies used numerical tools to replicate, predict or investigate different scenarios of the urban climate.
The numerical simulations in this thesis show that solar access is key for improving the outdoor thermal comfort in urban areas during the cool and cold seasons in Norway. Also, wind sheltering proves to be an effective measure, however, only at relatively high wind speeds and on a smaller scale than solar access. Changing the material properties of the urban surface in a dense urban environment only presents a negligible effect on outdoor thermal comfort during cool or cold weather conditions. Moreover, solar access is favorable in buildings, as in Norwegian climate conditions, south-oriented, unshaded windows can lead to more useful solar energy gains than detrimental energy losses, on an annual basis. The benefit of wind sheltering to lower a building’s energy demand is found to be small, as new buildings according to the Norwegian building regulations get increasingly airtight.
Furthermore, it is shown that especially during a summerly heat wave in Norway, the cooling energy demand and indoor overheating can be reduced effectively with vast urban greening compared to a concrete-sealed urban surface. While in summer the effects of different material compositions of the urban surface on the microclimatic conditions are very distinct, they are less pronounced in autumn and marginal in winter during the investigated conditions. Resulting from the proximity to the urban surface, the effect is strongest in the lower floors of a building.
This thesis underlines the importance of including urban microclimate in the planning process of buildings and neighborhoods, as well as giving it a stronger role in study syllabi. It shows that numerical modeling is a valuable resource for the understanding of the urban (micro)climate and gives detailed examples for its application. The results are intended to provide useful knowledge for researchers and practitioners in architecture, building engineering, and urban planning, as well as decision-makers in public authorities
Numerical Studies of Air Flow by Natural Convection in Ventilated Insulated Slanting Roofs
No full textA common roof design in the Scandinavian countries is the ventilated slanting roof. Ventilation of the roof has two purposes; to transport any moisture that has penetrated the roof construction out of the roof and to keep the outer roof surface cold enough to avoid snow melting. Snow melting on the roof's outer surface can cause pools of water freezing near the eave construction, which again can cause mechanical degradation and leakage. There have been some discussions regarding how large the air gap in ventilated roofs should be in order to provide sufficient ventilation for ensuring low temperatures and for allowing transport of moisture out of the roof. This paper presents temperature distribution, stream contours and mass flow rates found from 2D CFD simulations of natural convection is some typical roof configurations in Norway. The flow rates are reported for two sizes for the roofing battens, two different roof angles, and roof size. External wind effects are not included in these studies. The results may be used as input in heat and moisture simulation tools, where ventilated roof constructions are investigated.Presenters:
name: Arild Gustavsen
affiliation: (Norwegian University of Science and Technology)
email: [email protected]
Net zero greenhouse gas emission residential building concepts for warm climates
No full textCombating climate change and reducing the environmental impacts of human activities is the most urgent and challenging science and policy issue of the current time. Over 32% of global energy use and nearly 40% of global greenhouse gas emissions (GHG) can be attributed to building construction, maintenance, and service. These emissions may potentially increase three-fold by 2060 due to the rapid population growth and increased access to adequate housing, electricity, and improved facilities for the billions of people in developing economies. The dominant share of these GHG emission-intensive activities will occur in Asia, Africa, and Latin America, all of which have humid subtropical and tropical climates. Consequently, there is an urgent need to address environmental impacts related to the rapid growth of the residential construction sector in these climates. The goal of this thesis is to advance the development of sustainable, low GHG emission design strategies and residential building concepts, particularly those aimed at emerging countries covered by humid subtropical and tropical climates at the policy and design level.
The work presented in this thesis first focuses on improving the transparency and credibility of the net-zero GHG emission building definition and principles, whose implementation in the building design and national building policy is recognised as one of the most promising strategies for decarbonisation of the construction sector globally. The key methodological factors from selected international building standards and schemes were first identified and analysed and then organised and categorised into transparent and easy-to-understand frameworks. The results of the analysis determined that regulation type, system boundaries for both operational and embodied life cycle related GHG emission, approach (static vs dynamic) to the “time” aspect and the possibilities of GHG emission compensation are the most critical issues that should be focused on before creating a country-specific (net) zero GHG emission building framework.
The second research activity investigated the influence of climate conditions, electricity grid mix, and the level of energy efficiency requirements present in the local binding building regulations in Sydney, Atlanta, Shanghai, and New Delhi (all located in humid subtropical climate) firstly on the life cycle GHG emission balance, and secondly on the consequent feasibility of achieving the net-zero GHG emission performance target with a case single-family building powered by grid-connected, on-site PV energy system.
The results indicate that high-level energy-efficiency requirements present in the mandatory building standards in Sydney and Atlanta enable low energy operation and to achieve the net-zero GHG emission performance target with the analysed case building.
On the building design level, a systematic literature review was performed to identify the current state of the life cycle GHG emission profile of residential buildings in humid subtropical and tropical climates, as well as identify effective design strategies to reduce both embodied and operational GHG emissions and existing research gaps.
The results demonstrated that residential buildings with net-zero energy or low-energy performances could reduce the total life cycle GHG emission by 50–80% compared to the most common conventional energy performance of residential buildings, characterised by low energy efficiency. The design strategy connected with the implementation of renewable energy sources in the form of on-site photovoltaic systems was found to provide the highest reduction in total and operational life cycle GHG emissions, whereas the design strategy related to the use of timber-based materials led to the highest reduction in terms of embodied GHG emissions. Some identified research gaps relate to the lack of holistic life cycle assessment and design strategies for decreasing the environmental impact associated with prefabricated housing units and multifamily buildings in humid subtropical and tropical climates. The identified research gaps were covered in this thesis through the case study research based on the extensive use of building performance simulations (BPS) and life cycle assessments (LCA) with the support of global sensitivity analysis and multi-objective optimisation methods.
The case study research was based on a prefabricated housing unit with a conditioned floor area of 21m2 produced, located, and tested in Shanghai, China, and evaluated the correlation between energy use, indoor environmental quality, and the economics of various energy efficiency strategies in achieving net-zero energy and cost-effective off-grid operation. The design strategies related to relaxed cooling and heating temperature setpoints outside the building occupancy hours, increased thermal insulation thickness, upgrade to triple layer glazing, and implementation of a hybrid ventilation system were found to provide the most significant energy use savings.
The previous research was further developed by comparing different energy efficiency design concepts, including conventional, low-energy, zero-energy, and off-grid design scenarios, and considered the life cycle environmental impacts and the initial investment cost associated with exploring the possible environmental hotspots and trade-offs related to the increased energy efficiency and energy system complexity of the prefabricated housing module.
The life cycle environmental impacts were the lowest for the zero-energy design, with an 86% reduction of GHG emissions compared to the conventional one. The off-grid design presented substantially higher environmental impacts in all investigated categories (by an average of 59%) than the zero-energy design.
Finally, the thesis presents the results of a multifamily building case study located in three warm climate zones in India. The study illustrates the potential and the added value of using innovative approaches combining building performance simulation, life cycle assessment, and life cycle cost analysis with global sensitivity analysis and multi-objective optimisation. The findings of this research identified the most sensitive design parameters influencing life cycle GHG emissions and thermal comfort level, and the most promising design strategies to reduce the life cycle GHG emissions and cost in multifamily buildings located in humid subtropical and tropical climates. It was found that the apartment floor area, equipment loads, windows-to-floor ratio, mechanical ventilation airflow and cooling set-point temperature were the most influential design parameters for the life cycle GHG emissions in the multifamily building design located in each of the investigated warm climate locations. The design strategies, on the other hand, focused on increasing the space efficiency of the building apartments, minimising the area of windows and the solar heat gain coefficient, implementing the hybrid cooling system with the use of ceiling fans and maximising energy generation from the on-site PV system. Implementation of these design strategies provided the best life cycle performance including GHG emissions and life cycle cost.
The main contribution of this thesis is the holistic and combined analysis based on the life cycle approach of residential buildings in humid subtropical and tropical climates at the policy and building design level, which has revealed critical variables and offers practical recommendations and concepts towards the successful mitigation of the effects of climate change in the residential construction sector
Heat transfer in window frames with internal cavities
No full textHeat transfer in window frames with internal air cavities is studied in this thesis. Investigations focus on two- and three-dimensional natural convection effects inside air cavities, the dependence of the emissivity on the thermal transmittance, and the emissivity of anodized and untreated aluminum profiles. The investigations are mostly conducted on window frames which are the same size as real frames found in residential buildings.
Numerical and experimental investigations were performed to study the effectiveness of one commercial Computational Fluid Dynamics (CFD) program for simulating combined natural convection and heat transfer in simple three-dimensional window frames with internal air cavities. The accuracy of the conjugate CFD simulations was evaluated by comparing results for surface temperature on the warm side of the specimens to results from experiments that use infrared (IR) thermography to map surface temperatures during steady-state thermal tests. In general, there was good agreement between the simulations and experiments.
Two-dimensional computational fluid dynamics and conduction simulations are performed to study the difference between treating air cavities as a fluid and as a solid when calculating the thermal transmittance of window frames. The simulations show that traditional software codes, simulating only conduction and using equivalent conductivities for the air cavities, give U- values that compare well with results from fluid flow simulations. The difference between the two models are mostly limited to the temperature distribution inside air cavities. It is also found that cavities with an interconnection less than about 7 mm can be treated as separate cavities.
Three-dimensional natural convection effects in simple and custom-made PVC and thermally broken aluminum window frames with one open internal cavity were studied, with the use of CFD simulations and thermography experiments. Focus was put on corner effects and heat transfer rates. From the results it appears that the thermal transmittance of a four-sided section can be found by calculating the average of the thermal transmittance of the respective single horizontal and vertical sections. In addition, it was found that two-dimensinal conduction heat transfer simulation software agrees well with tree-dimensional CFD simulations if the natural convection correlations used for the internal cavities are correct.
Numerical studies were done with natural convection in three-dimensional cavities with a high vertical aspect ratio and a low horizontal aspect ratio. The cavities studied had vertical aspect ratios of 20, 40, and 80 and horizontal aspect ratios ranging from 0,2 to 5. It was shown that three-dimensional cavities with a horizontal aspect ratio larger than five can be considered to be a two-dimensional cavity to within 4 % when considering heat transfer rates. Nusselt number correlations for the different horizontal aspect ratios are presented for cavities with vertical aspect ratios of 20 and 40. Complex multicellular flow was studied for the case where the vertical and horizontal aspect ratios were 40 and 2, respectively.
Experimental studies included the normal spectral and total emissivity of specimens from six meter long untreated and anodized aluminum profiles. Specimens facing the internal cavities (thermal break cavity and all aluminum cavity) were measured. Some masking tapes often used in hot box experiments were also measured. The normal total emissivity was found to be is fairly constant (between 0.834 and 0.856) for exterior parts of the anodized profile and for surfaces facing the thermal break cavity. The normal total emissivity of the all-aluminum internal cavities was found to vary between 0.055 and 0.82. The experiments were performed with a Fourier transform infrared spectrometer in the wavelength interval from 4.5 to 40 μm.dr.ing.dr.ing
Heat transfer in window frames with internal cavities
No full textHeat transfer in window frames with internal air cavities is studied in this thesis. Investigations focus on two- and three-dimensional natural convection effects inside air cavities, the dependence of the emissivity on the thermal transmittance, and the emissivity of anodized and untreated aluminum profiles. The investigations are mostly conducted on window frames which are the same size as real frames found in residential buildings.
Numerical and experimental investigations were performed to study the effectiveness of one commercial Computational Fluid Dynamics (CFD) program for simulating combined natural convection and heat transfer in simple three-dimensional window frames with internal air cavities. The accuracy of the conjugate CFD simulations was evaluated by comparing results for surface temperature on the warm side of the specimens to results from experiments that use infrared (IR) thermography to map surface temperatures during steady-state thermal tests. In general, there was good agreement between the simulations and experiments.
Two-dimensional computational fluid dynamics and conduction simulations are performed to study the difference between treating air cavities as a fluid and as a solid when calculating the thermal transmittance of window frames. The simulations show that traditional software codes, simulating only conduction and using equivalent conductivities for the air cavities, give U- values that compare well with results from fluid flow simulations. The difference between the two models are mostly limited to the temperature distribution inside air cavities. It is also found that cavities with an interconnection less than about 7 mm can be treated as separate cavities.
Three-dimensional natural convection effects in simple and custom-made PVC and thermally broken aluminum window frames with one open internal cavity were studied, with the use of CFD simulations and thermography experiments. Focus was put on corner effects and heat transfer rates. From the results it appears that the thermal transmittance of a four-sided section can be found by calculating the average of the thermal transmittance of the respective single horizontal and vertical sections. In addition, it was found that two-dimensinal conduction heat transfer simulation software agrees well with tree-dimensional CFD simulations if the natural convection correlations used for the internal cavities are correct.
Numerical studies were done with natural convection in three-dimensional cavities with a high vertical aspect ratio and a low horizontal aspect ratio. The cavities studied had vertical aspect ratios of 20, 40, and 80 and horizontal aspect ratios ranging from 0,2 to 5. It was shown that three-dimensional cavities with a horizontal aspect ratio larger than five can be considered to be a two-dimensional cavity to within 4 % when considering heat transfer rates. Nusselt number correlations for the different horizontal aspect ratios are presented for cavities with vertical aspect ratios of 20 and 40. Complex multicellular flow was studied for the case where the vertical and horizontal aspect ratios were 40 and 2, respectively.
Experimental studies included the normal spectral and total emissivity of specimens from six meter long untreated and anodized aluminum profiles. Specimens facing the internal cavities (thermal break cavity and all aluminum cavity) were measured. Some masking tapes often used in hot box experiments were also measured. The normal total emissivity was found to be is fairly constant (between 0.834 and 0.856) for exterior parts of the anodized profile and for surfaces facing the thermal break cavity. The normal total emissivity of the all-aluminum internal cavities was found to vary between 0.055 and 0.82. The experiments were performed with a Fourier transform infrared spectrometer in the wavelength interval from 4.5 to 40 μm.dr.ing.dr.ing
Advanced Building Envelopes: Opportunities, challenges, and future outlooks in building performance simulation
No full textResearch in buildings has lately focused on tackling two main issues: reducing energy use and building better and faster to cope with the expected expansion of cities. The building industry has struggled to adapt to these changes as it is one of the world's largest industries yet one of the least digitalized. One of the challenges is that buildings are becoming more complex to meet these goals and integrate more technologies like renewable energy systems. As a result, there is a need to adopt new methods and tools for designing buildings.
This PhD thesis focused on the design and development of Advanced Building Envelopes (ABEs), which are also sometimes referred to as smart, intelligent, or adaptive building envelopes. ABEs are innovative systems that intend to balance multiple performance aspects such as sustainability, aesthetics, and comfortable indoor environments using new technologies and design approaches. Examples of ABEs may be shading systems that slowly adapt their shape during the day following the sun's path or envelope components specifically designed to optimize energy flows and indoor comfort while harvesting solar energy.
This thesis aims to increase the uptake of ABEs in real-world projects by contributing to characterization systems of new envelope technologies and demonstrating the use of performance-based design approaches. Additionally, it also provided robustness assessments and developed best practice guidelines. This work includes simulations of a specific type of ABE that was an external Venetian blind system with integrated photovoltaic modules. The work developed for the case study used a combination of co-simulation, parametric design, and optimization. The actual performance of the system was also verified in a full-scale experiment.
The thesis' findings highlight that using a performance-based approach had several advantages in addition to providing accurate results. Parametrizing the system's design allowed searching and evaluating many more design alternatives, where eclectic designs could be considered and assessed in a much more efficient manner. Using optimization and co-simulation also allowed generating a set of higher-performing solutions from which one could select a suitable alternative. Finally, this work underlines that new design and evaluation methods can be integrated with initiatives aiming to digitalize building processes and increase collaboration across different engineering fields. However, the types of approaches also require users to develop inter-disciplinary skills and challenge the traditional separation of tasks between architects, engineers, and data scientists
Constructing Industrial Architecture: The Evolution of Technology and Architecture Style at the Rjukan-Notodden Industrial Heritage Site in Norway (1905–1929)
No full textEnglish summary
This study aims to establish how the development of construction technology influenced industrial architecture at Rjukan and Notodden in Norway. A total of twenty-four buildings that still exist today have been recorded and studied; these buildings represent the period from 1905 until 1929. This is a relatively short period in time with few buildings built and therefore cannot be representative of the developments of an entire industry. This can be considered a limitation when aiming to understand the history of construction technology and international developments. The industrial buildings and construction systems have not been researched before and the ten identified systems present a very distinct and historically important development at this United Nations Educational, Scientific and Cultural Organization (UNESCO) site. This is also why the scope of this research based its framework on buildings that are still standing today. The objective is to support future conservation schemes of industrial heritage buildings.
Constant change in industrial production demanded and challenged building design. It appears that construction systems evolved from brick-based structures in the first period of 1905–1912 to hybrid structures and clearly defined skeleton systems from concrete and steel during the following period from 1912 until 1920. The systems of the third period, from 1920 until 1929, were built on technology such as steel and concrete skeleton structures. They were developed further to be more efficient with material use and construction time. Analysis of the systems shows that brick, a material that previously dominated the construction of industrial buildings in Norway, gradually became obsolete. Increasing demand for faster construction speeds through prefabrication and short on-site assembling made the use of brick less desirable. Concrete, on the other hand, indefinitely secured a position as a primary construction material. Concrete bearing walls and mixed bearing walls, however, demand significant material resources. This is something the concrete skeleton frame reduces through defined load paths. The development from heavy structures to lighter, defined frames characterises the systems through the respective periods in time.
The studied and identified systems also illustrate that architects, but mainly engineers and contractors, experimented with a combination of individual systems. Understanding complex structures and the engineering science behind them is essential when embarking on large design projects like hydropower stations. Steel, although not new at the time, asserted its dominance through either mixed structures or completely independent steel skeleton frames. Steel skeleton frames were quickly and efficiently constructed without the use of concrete. Based on the findings of construction systems and their characteristics, it can be concluded that the buildings in Rjukan and Notodden are not only connected to international technological development of industrial buildings but also other typologies such as skyscrapers. Innovations in structural engineering and architecture had a profound influence on engineers and architects who worked with this site. This confirms that this Norwegian site is no isolated development.Norsk sammendrag
Sammendrag
Formålet med denne forskningen er å undersøke hvordan utviklingen av bygningsteknologi har påvirket industriarkitektur i perioden mellom 1905 til 1929. Derfor har 24 eksisterende bygninger i UNESCO verdensarvområde Rjukan og Notodden blitt undersøkt og studert. Dette er en relativt kort periode med relativ få case-bygninger og forskningsprosjektet kan derfor ikke være representativ for utviklingen i hele fagfeltet industriarkitektur. Dette kan betraktes som en begrensning når man ønsker å belyse norsk teknologi og arkitekturhistorie i en internasjonal sammenheng. Det har ikke blitt forsket på industribygninger og konstruksjonssystemene tidligere på dette UNESCO-verdensarvsted og kunnskapen er derfor mangelfullt. De 10 systemene som er identifisert og som er beskrevet, representerer derfor en historisk viktig utvikling. Dette er også grunnen til at omfanget av forskningen setter søkelys på eksisterende bygninger. Et av forskningsmålene er å støtte gjennom ny kunnskap fremtidige bevaringsprosjekter.
Stadige endringer i industriproduksjonen utfordret bygningsdesign og teknologien. Det viser seg at konstruksjonssystemer utviklet seg fra tradisjonelle teglbaserte konstruksjoner i den første perioden mellom 1905 og 1912 til hybridkonstruksjoner og skjelettsystemer bygget fra betong og stål i den påfølgende perioden fra 1912 til 1920. Konstruksjonssystemene fra den tredje perioden 1920 til 1929, ble bygget på dette og teknologien ble mer avansert med dypere kunnskap om konstruksjonsteknikk og materialstyrke. Dette resulterte i konstruksjoner som stål- og betongskjeletter. Analysen av konstruksjonsprinsippene viser at tegl, et materiale som har dominert byggingen av industribygg i Norge, etter hvert ble utdatert og forsvant. Økende etterspørsel etter prefabrikasjon og rask montering på byggeplassen gjorde bruk av tegl mindre ønskelig. Betong, derimot, sementerte definitivt en posisjon som primært byggemateriale. Tidlige tunge konstruksjonsprinsipper i betong krevde imidlertid betydelige materialressurser. Gjennom stadig økende kunnskap om lastoverføring og materialenes fasthetslære ble skjelettkonstruksjonen utviklet og dens vekt betydelig redusert. Gjennom de tre undersøkte tidsperiodene har det blitt registrert at det er en tydelig utvikling fra tunge konstruksjoner til lette byggesystemer.
De studerte og identifiserte konstruksjonsprinsippene viser også at arkitekter, men hovedsakelig ingeniører og entreprenører, eksperimenterte med en kombinasjon av flere systemer. Det var avgjørende å ha kunnskap om ingeniørvitenskap når komplekse industrikonstruksjoner og vannkraftverk skulle bygges. Stål som byggemateriale var ikke nytt på den tiden, men manifesterer sin dominans gjennom prefabrikkerte skjelettkonstruksjoner. De ble raskt og effektivt konstruert og bygget nesten uten bruk av betong. Basert på funn av konstruksjonsprinsippene kan det konkluderes med at industribygninger på Rjukan og Notodden ikke bare er knyttet til en internasjonal teknologiutvikling av industribygg, men også andre bygningstypologier som skyskrapere. Internasjonal innovasjon innen arkitektur og konstruksjonsteknikk hadde betydelig innflytelse på ingeniører og arkitekter som jobbet med industribygninger på Rjukan og Notodden. Det er en bekreftelse på at dette norske industristedet ikke har vært isolert, men er del av den globale arkitektur utviklingen.Fulltext not availabl
Advanced Building Envelopes: Opportunities, challenges, and future outlooks in building performance simulation
No full textResearch in buildings has lately focused on tackling two main issues: reducing energy use and building better and faster to cope with the expected expansion of cities. The building industry has struggled to adapt to these changes as it is one of the world's largest industries yet one of the least digitalized. One of the challenges is that buildings are becoming more complex to meet these goals and integrate more technologies like renewable energy systems. As a result, there is a need to adopt new methods and tools for designing buildings.
This PhD thesis focused on the design and development of Advanced Building Envelopes (ABEs), which are also sometimes referred to as smart, intelligent, or adaptive building envelopes. ABEs are innovative systems that intend to balance multiple performance aspects such as sustainability, aesthetics, and comfortable indoor environments using new technologies and design approaches. Examples of ABEs may be shading systems that slowly adapt their shape during the day following the sun's path or envelope components specifically designed to optimize energy flows and indoor comfort while harvesting solar energy.
This thesis aims to increase the uptake of ABEs in real-world projects by contributing to characterization systems of new envelope technologies and demonstrating the use of performance-based design approaches. Additionally, it also provided robustness assessments and developed best practice guidelines. This work includes simulations of a specific type of ABE that was an external Venetian blind system with integrated photovoltaic modules. The work developed for the case study used a combination of co-simulation, parametric design, and optimization. The actual performance of the system was also verified in a full-scale experiment.
The thesis' findings highlight that using a performance-based approach had several advantages in addition to providing accurate results. Parametrizing the system's design allowed searching and evaluating many more design alternatives, where eclectic designs could be considered and assessed in a much more efficient manner. Using optimization and co-simulation also allowed generating a set of higher-performing solutions from which one could select a suitable alternative. Finally, this work underlines that new design and evaluation methods can be integrated with initiatives aiming to digitalize building processes and increase collaboration across different engineering fields. However, the types of approaches also require users to develop inter-disciplinary skills and challenge the traditional separation of tasks between architects, engineers, and data scientists.Sammendrag
Forskning innen bygg har det siste tiåret fokusert på å takle to hovedproblem: øke i byggsektoren og å bygge bedre og raskere for å takle den forventede befolkningsøkningen. Byggebransjen sliter med å tilpasse seg disse endringene, da den er en av verdens største næringer, men samtidig en av de minst digitaliserte. En av utfordringene er at bygninger blir stadig mer komplekse for å nå disse målene, siden de må ta hensyn til flere ting som energifleksibilitet og må integrere fornybare energiteknologier på bygningen. Dette fører til at det er et behov for å ta i bruk nye metoder og verktøy som kan hjelpe til å utforme fremtidens bygninger.
Denne doktorgradsavhandling handler om design og utvikling av avanserte tak- og fasadekomponenter som kan gå under betegnelsen "Advanced Building Envelopes" (ABEs). Disse innovative bygningskomponentene er ofte også kjent som smarte fasader og bruker nye teknologier og systemer for å balansere bærekraft, estetikk og et godt inneklima.
Denne oppgaven har som mål å øke bruken av ABE i prosjekter ved å bidra til å forbedre hvordan disse teknologiene karakteriseres i dag, og demonstrerer bruken og resultatet av ytelsesbaserte designmetodikker. I denne sammenheng ble robustheten av resultatene vurdert, og det ble utviklet retningslinjer for beste praksis. Arbeidet utført i denne oppgaven baserer seg på simuleringsstudier av en casestudie, som er et solskjermingssystem med utvendige persienner og integrerte solcellemoduler. Simuleringene kombinerte koordinerte energi og dagslyssimuleringer (co-simulering), parametrisk modellering og optimering. Til slutt ble systemet også vurdert ved hjelp av et fullskala eksperimentelt oppsett.
Funnene i oppgaven fremhevet at bruken av en ytelsesbasert metodikk hadde flere fordeler. For det første gjorde bruken av parametrisk design det mulig å søke mange flere designalternativer, samtidig som et utvalgt design kunne vurderes på en mye mer effektiv måte og med god nøyaktighet. For det andre tillot optimering og co-simulering å komme frem til et sett løsninger med høy ytelse hvorfra man enkelt kunne velge et spesifikt alternativ.
Dette arbeidet understreker også at nye design- og evalueringsmetoder som tar i bruk simuleringsverktøy også kan integreres med initiativer for å digitalisere byggeprosesser og øke samarbeidet på tvers av interessenter. Likevel krever disse verktøyene tverrfaglig kunnskap fra brukerne for å kunne gi gode resultater, noe som utfordrer det tradisjonelle skillet mellom fagene arkitektur, ingeniørvitenskap og datavitenskap
The Climate Dimension in the Design of Resilient Urban Neighborhoods in Norway: A study on materials, outdoor thermal comfort, and building energy demand in the context of the urban microclimate
No full textOne of the 17 Sustainable Development Goals proclaimed in the 2030 Agenda for Sustainable Development by the United Nations is Sustainable Cities and Communities. In the view of urbanization and a rising world population, the ambition is to create and transform cities into climate-resilient, safe, healthy, climate-friendly, and livable environments for its citizens. This thesis aims to contribute to this goal in the context of Norwegian climate conditions. For that, multiple approaches and methodologies are used.
First, an extensive literature study is conducted to synthesize the characteristics of the urban climate, focus areas, and research gaps from scientific publications addressing cold and polar climate regions. Second, numerical tools including computational fluid dynamics (CFD) and building performance simulation (BPS) are used to create models for studying the effect of different climates and design scenarios particularly with regard to people’s outdoor thermal comfort and building energy demand. Field measurements of relevant climate variables from a network of fixed and temporary weather stations are used to provide input and validation data for the numerical models predicting the local climate conditions in an urban neighborhood (microclimate). Finally, a coupling methodology for CFD and BPS is presented that allows investigation of the energy demand of different floors of a high-rise building considering vertical temperature gradients derived from CFD simulations. For most of the thesis work, the Gløshaugen campus of the Norwegian University of Science and Technology which is currently under redevelopment served as a case study.
From the literature review, it was found that the urban climate in cold climate regions is strongly affected by the presence of the urban heat island (UHI). Mostly, observational methods were used and only 22 % of the reviewed studies used numerical tools to replicate, predict or investigate different scenarios of the urban climate.
The numerical simulations in this thesis show that solar access is key for improving the outdoor thermal comfort in urban areas during the cool and cold seasons in Norway. Also, wind sheltering proves to be an effective measure, however, only at relatively high wind speeds and on a smaller scale than solar access. Changing the material properties of the urban surface in a dense urban environment only presents a negligible effect on outdoor thermal comfort during cool or cold weather conditions. Moreover, solar access is favorable in buildings, as in Norwegian climate conditions, south-oriented, unshaded windows can lead to more useful solar energy gains than detrimental energy losses, on an annual basis. The benefit of wind sheltering to lower a building’s energy demand is found to be small, as new buildings according to the Norwegian building regulations get increasingly airtight.
Furthermore, it is shown that especially during a summerly heat wave in Norway, the cooling energy demand and indoor overheating can be reduced effectively with vast urban greening compared to a concrete-sealed urban surface. While in summer the effects of different material compositions of the urban surface on the microclimatic conditions are very distinct, they are less pronounced in autumn and marginal in winter during the investigated conditions. Resulting from the proximity to the urban surface, the effect is strongest in the lower floors of a building.
This thesis underlines the importance of including urban microclimate in the planning process of buildings and neighborhoods, as well as giving it a stronger role in study syllabi. It shows that numerical modeling is a valuable resource for the understanding of the urban (micro)climate and gives detailed examples for its application. The results are intended to provide useful knowledge for researchers and practitioners in architecture, building engineering, and urban planning, as well as decision-makers in public authorities
The Workplace of the Future : The Fourth Industrial Revolution, the Precariat and the Death of Hierarchies /
No full textThe Fourth Industrial Revolution is a global development that shows no signs of slowing down. In his book, The Workplace of the Future: The Fourth Industrial Revolution, the Precariat and the Death of Hierarchies, Jon-Arild Johannessen sets a chilling vision of how robots and artificial intelligence will completely disrupt and transform working life. The author contests that once the dust has settled from the Fourth Industrial Revolution, workplaces and professions will be unrecognizable and we will see the rise of a new social class: the precariat. We will live side by side with the 'working poor' – people who have several jobs, but still can’t make ends meet. There will be a small salaried elite consisting of innovation and knowledge workers. Slightly further into the future, there will be a major transformation in professional environments. Johannessen also presents a typology for the precariat, the uncertain work that is created and develops a framework for the working poor, as well as for future innovation and knowledge workers, and sets out a new structure for the social hierarchy.A fascinating and thought-provoking insight into the impact of the Fourth Industrial Revolution, The Workplace of the Future will be of interest to professionals and academics alike. The book is particularly suited to academic courses in management, economy, political science and social sciences.Includes bibliographical references and index.The Fourth Industrial Revolution is a global development that shows no signs of slowing down. In his book, The Workplace of the Future: The Fourth Industrial Revolution, the Precariat and the Death of Hierarchies, Jon-Arild Johannessen sets a chilling vision of how robots and artificial intelligence will completely disrupt and transform working life. The author contests that once the dust has settled from the Fourth Industrial Revolution, workplaces and professions will be unrecognizable and we will see the rise of a new social class: the precariat. We will live side by side with the 'working poor' – people who have several jobs, but still can’t make ends meet. There will be a small salaried elite consisting of innovation and knowledge workers. Slightly further into the future, there will be a major transformation in professional environments. Johannessen also presents a typology for the precariat, the uncertain work that is created and develops a framework for the working poor, as well as for future innovation and knowledge workers, and sets out a new structure for the social hierarchy.A fascinating and thought-provoking insight into the impact of the Fourth Industrial Revolution, The Workplace of the Future will be of interest to professionals and academics alike. The book is particularly suited to academic courses in management, economy, political science and social sciences
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