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Purpose The purpose of this paper is to identify appropriate concepts of multi-active façades for the renovation of multifamily buildings in Sweden and to determine which, if any, are financially viable. Design/methodology/approach A lifecycle profit (LCP) analysis was used to examine financial viability through a ten-step process, which included identifying concepts, assessing costs and prices, calculating the LCP and performing sensitivity analysis. Two existing buildings – one low rise and the other high rise – were used as reference models. Findings The findings were contradictory. Implementing any of the multi-active façade concepts on the high-rise building would be financially beneficial. The opposite was, however, the case for the low-rise building. Two factors causing this contradiction have been identified: the façade material before renovation and the size of the building. Research limitations/implications The study is limited to two case buildings situated in Sweden; however, similar buildings represent a significant amount of the existing building stock. Part of the purpose of the study is also to investigate the merits of LCP analysis to evaluate energy-efficient retrofitting. The study implicates the benefits and pitfalls of LCP analysis needed to be considered by researchers and practitioners alike. Originality/value The research findings contribute to the understanding of energy-efficient retrofitting of existing multifamily buildings based on prefabricated multi-active façade concepts.

Purpose This paper is based on a study of six similar buildings built in Gothenburg, Sweden, in 1971, which were in urgent need of renovation. A life cycle profit analysis shows how four competing concepts were evaluated to find a financially viable renovation concept; additionally, the environmental impacts of these renovation concepts using a life cycle assessment are presented. Design/methodology/approach Four renovation concepts are compared to find the most appropriate concept, namely, minimalist, code-compliant, low-energy and low-energy plus vertical extension concepts. The methods used for comparison are life cycle profit analysis and life cycle impact assessment; the methods used for data gathering included site visits, interviews, document study, co-benefits study and energy simulation. Findings The findings show that vertical extension supported the energy-efficient renovation of the buildings and that the combination of low-energy and the vertical extension had the highest return on investment and the lowest environmental impact. The selected concept for renovating the remaining five buildings combined was the low-energy plus vertical extension. Additional benefits from vertical extension include more apartments in central locations for the housing company, a wider variety of apartment layouts and a wider range of tenants. Drawbacks include increased use of infrastructure, green space and common appliances, as well as gentrification. Originality/value This study shows how a vertical extension can financially enable an energy-efficient renovation and further lower its environmental impact. Benefits and drawbacks of densification are also highlighted to better understand the implementation of vertically extending a building.

This paper evaluates the cost-effectiveness of renovating single-family houses to Passive House level, as compared to maintaining the existing buildings or renovating to building regulation level. The assessment involved life cycle cost analyses, and concerns the Swedish single-family housing stock constructed between 1961 and 1980, which accounts for about a third of Sweden’s two million single-family houses. These houses, now in need of major renovation, are represented in this study by two reference buildings. The results show that Passive House renovations can be cost-effective, but this largely depends on the type of heat generation used in the houses. The most cost-effective individual renovation measure was installing an exhaust air heat pump, and the least cost-effective was installing new windows. In houses using direct electric heating, the Passive House renovation package was the most cost-effective alternative.

To meet EU energy and climate targets, energy efficiency of the existing building stock must bedrastically improved. Within IEA EBC Annex 56 one of the best practice examples of energy renovations is a group of multi- family buildings in Sweden, recently thoroughly renovated. For this group of buildings the residents’ perception of renovations and appraisal of implemented measures were captured by interviews with tenants and a literature review. Residents’ possible acceptance of energy renovations are related to improvements that are directly experienced and visible. Resident participation is beneficial. Crucial is the collaboration between all stakeholders. Long-term environmental benefits or financial gains are arguments that might not be sufficient.

This paper evaluates whether a net-zero energy building (NZEB) can be attained by implementing on-site renewable electricity production when renovating to Passive House level. The assessment is based on the Swedish single-family housing stock constructed between 1961 and 1980, using two case study houses and three locations. Specific conditions of the houses, such as the type of heat generation and available roof area for installation of a photovoltaic system, determine whether a NZEB renovation is possible. Overall, the assessment showed that it is not cost-effective to aim for NZEB when implementing a PV system, based on the alternatives in this study.

This article presents key energy use figures and explores the energy saving potential for electric lighting in office buildings based on a review of relevant literature, with special emphasis on a North European context. The review reveals that theoretical calculations, measurements in full-scale rooms and simulations with validated lighting programs indicate that an energy intensity of around 10 kWh/m(2) yr is a realistic target for office electric lighting in future low energy office buildings. This target would yield a significant reduction in energy intensity of at least 50% compared to the actual average electricity use for lighting (21 kWh/m(2) yr in Sweden). Strategies for reducing energy use for electric lighting are presented and discussed, which include: improvements in lamp, ballast and luminaire technology, use of task/ambient lighting, improvement in maintenance and utilization factor, reduction of maintained illuminance levels and total switch-on time, use of manual dimming and switch-off occupancy sensors. Strategies based on daylight harvesting are also presented and the relevant design aspects such as effects of window characteristics, properties of shading devices, reflectance of inner surfaces, ceiling and partition height are discussed. (C) 2011 Elsevier B.V. All rights reserved. (Less)

Highly glazed buildings are designed by architects to be airy, light and transparent with more access to daylight. Their energy efficiency, however, has become questioned. Therefore, energy simulations of single skin office buildings in Sweden were carried out, using a dynamic energy simulation tool. In order to study the impact of glass on the energy use during the occupation stage, office building alternatives with 30, 60 and 100% window to external wall area were studied. Other varied parameters were the building's orientation, the plan type (open and cell plan offices), the control set points and the facade elements (type and size of windows, type and position of shading devices, etc.). The main conclusion is that careful design is needed to ensure low energy use and good thermal comfort, especially for highly glazed office buildings. Careful design of glazed office buildings has to be based on detailed thermal simulations. Especially in fully glazed buildings (in which the facade is more “sensitive” to climatic conditions), proper combination of control set points, glazing and solar shading are crucial for the energy performance. A sensitivity analysis of single skin glazed office buildings was one of the main aims of the study. Although it was concluded that highly glazed single skin buildings are likely to consume more energy during the occupation stage, after studying the impact of shadings, window types, etc., the increase was lowered to 15% (100% glazed alternative compared to a typical reference building with 30% window to external wall area) maintaining at the same time an acceptable level of thermal comfort.

The project BESTFACADE, sponsored by the Energy Intelligent Europe programme of the European Union, and led by MCE-Anlagenbau, Austria, accumulated the state of the art of double skin facades (DSFs) in seven European countries (Austria, Belgium, France, Germany, Greece, Portugal and Sweden). Twenty-eight facades of different buildings in all partner countries of BESTFACADE have been analysed for the aspects, types of facade in different countries, DSFs in different climatic regions of Europe, existing simulations and measurements, thermal behaviour, indoor air quality, comfort, user acceptance, energy demand and consumptions, control strategies, integrated building technology, cost (investment, maintenance and operation), resource conservation, environmental impact, comparison to conventional glass facades (CGFs), integration of renewable energy sources into DSFs, as well as non-energy related issues, such as, acoustics, aesthetics, fire protection, moisture, corrosion, durability, maintenance an...

Although low-energy and nearly zero-energy residential houses have been built in Sweden in the past decade, there are very few examples of low-energy office buildings. This paper investigates the design features affecting energy use in office buildings and suggests the optimal low-energy design from a Swedish perspective. Dynamic simulations have been carried out with IDA ICE 4 on a typical narrow office building with perimeter cell rooms. The results from the parametric study reveal that the most important design features for energy saving are demand-controlled ventilation as well as limited glazing on the facade. Further energy-saving features are efficient lighting and office equipment which strongly reduce user-related electricity and cooling energy. Together, the simulation results suggest that about 48% energy can be saved compared to a new office building built according to the Swedish building code. Thus, it is possible, using a combination of simple and well-known building technologies and configurations, to have very low energy use in new office buildings. If renewable energy sources, such as solar energy and wind power, are added, there is a potential for the annual energy production to exceed the annual energy consumption and a net zero-energy building can be reached. One aspect of the results concerns user-related electricity, which becomes a major energy post in very low-energy offices and which is rarely regulated in building codes today. This results not only in high electricity use, but also in large internal heat gains and unnecessary high cooling loads given the high latitude and cold climate.

A third of Sweden's two million single-family houses were built in the period 1961-1980, and many of them are in need of renovation. These houses have a high energy use and are in technical terms fairly homogenous. This investigation evaluates the theoretical energy savings potential of renovating houses from this period. Four reference houses were selected and simulated using common renovation measures. The results indicate that most of the existing single-family housing stock will likely not be able to attain the passive house standard after renovation and using today's technology. This is explained by the fact that some house characteristics impose a limiting factor on the energy renovation. Such examples are the shape, foundation and composition of the building envelope. Nevertheless, it is still possible to drastically reduce the final energy use by approximately 65-75%.

ABSTRACT IN ENGLISH----------------------------------------------------------- The rational use of energy is a major challenge that today’s societies have to win in order to preserve the environment as well as protect their economical, social and political development. A major step in this direction is to reduce the energy consumption of existing buildings. Among existing certifications, the Passive House standards guarantee the best energy performance (regarding heating demand). However, the vast majority of Passive House buildings are new residential constructions with some refurbishment projects. This report assesses the feasibility of the implementation of Passive House standards in public buildings, retrofitted as well as new constructions. The state of the art practices for residential buildings was first analyzed. Case studies of Passive House standard buildings were studied to complement this first part. Conclusions regarding the differences between residential and public buildings were then drawn in order to outline the needed adaptations. A case study of a representative university building in Brussels, Belgium comprising different functions was then modeled in the dynamic building energy simulation software DEROB-LTH for running parametric studies. The combination of found optimal values was used to produce a Passive House standards’ building. The latter constituted a basis for the establishment of guidelines regarding the implementation of Passive House standards in existing public buildings such as educational and office buildings. Results show that it should be possible to implement Passive House standards in this type of buildings. Great care should however be taken regarding the cooling demand that increases with improved thermal performance of the envelope. Night ventilation strategies combined with installation of high-efficiency lighting systems and electronic equipments is needed. Heat recovery systems are also necessary for guaranteeing a low heat demand. Active systems can hardly be dismissed., ABSTRACT EN FRANCAIS---------------------------------------------------------- L’utilisation rationnelle de l’énergie est un défi majeur que les sociétés d’aujourd’hui doivent gagner afin de préserver l’environnement ainsi que leurs développements économique, social et politique. Un pas majeur dans cette direction est la réduction de la consommation énergétique liée aux bâtiments. Parmi les certifications existantes, le standard « maison passive » garantie la meilleure performance énergétique (concernant la demande de chauffage). Néanmoins, l’écrasante majorité de bâtiments certifiés « maison passive » est constituée de nouvelles constructions résidentielles et quelques projets de rénovation seulement. Ce travail examine la faisabilité d’application du standard « maison passive » dans les bâtiments recevant du public, rénovés et récemment construits. L’état de l’art des pratiques pour les bâtiments résidentiels a d’abord été analysé. Des études de cas de bâtiments répondant aux critères « maison passive » ont été étudiées afin de complémenter cette première partie. Les différences entre bâtiments résidentiels et publics ont alors été établies afin de préciser les adaptations nécessaires. Une étude de cas d’un bâtiment universitaire (représentatif du parc bâti en terme de consommation énergétique) à Bruxelles en Belgique comprenant différentes fonctions a alors été modélisé à travers le programme de simulation énergétique dynamique du bâtiment DEROBLTH afin de réaliser des études paramétriques. La combinaison des valeurs optimales trouvées a été utilisée afin de produire un bâtiment passif. Ce dernier, a servi de base pour l’établissement de lignes directrices concernant l’application du standard « maison passive » dans les bâtiments existant recevant du public. Les résultats montrent qu’il serait possible d’appliquer le standard « maison passive » dans ce type de bâtiments. Une attention particulière doit néanmoins être portée sur la demande de refroidissement qui augmente avec une amélioration de la performance thermique de l’enveloppe. Des stratégies de ventilations nocturnes combinées avec l’installation de systèmes d’éclairage et d’équipements électroniques haute performance sont requises. Des systèmes de récupération de chaleur sont de même nécessaires pour garantir une faible demande en chauffage. Les systèmes actifs peuvent difficilement être écartés., info:eu-repo/semantics/nonPublished