Dagens byggeforskrifter krever mye ekstra dokumentasjon om en ikke skal ha balansert ventilasjon, og dette legger i praksis sterke føringer for valg av ventilasjonsløsning. Imidlertid er klimagassutslipp med ulike ventilasjons-konsept i liten grad undersøkt.

Moving away from the annual energy budget and including the emissions of the entire building lifetime during construction, operation, and disposal is a key aspect of ZEB. This can be summarised in an emission inventory of operation and building components and services. The aim of this paper is to investigate the emission balance of both operational and the embodied energy in different highly energy efficient buildings concepts which are worth considering toward achieving Zero emission buildings. In this work four concepts for energy efficient buildings are identified which could provide stepping stones towards a definition of ZEB. These concepts were applied to a generic model (´shoe box model´) of a detached house. The greenhouse gas emissions in kilogrammes CO2 equivalents over buildings lifetime due to embodied and operational energy were accounted for three possible approaches towards achieving a Zero Emission Building. A reference building was used as a base case which is a passive house with reference materials used in the commonly used Norwegian construction. The first alternative aims at zero operational energy disregarding the embodied energy in the materials. The second alternative tries to reduce the embodied energy based on \'low emission\' material choice, without efforts to improve the energy performance. Alternative three combines both measures from alternative 1 and 2. When applying the UCTE electricity mix, representing the present electricity infrastructure, clearly most emissions are related to operation. Therefore alternatives 1 and 2 without operational emissions have significantly lower emissions. Applying other electricity mix representing a de-carbonised electricity grid, the differences are less distinct. And since electricity is also part of the emissions of building materials as electricity factor for the production the results might align even more. Hereby also the location of production gains increased importance. Windows, foundations, slab to ground, floor slabs of the building components and sanitary installation, ventilation system of the building services show high emissions in all four cases. Two main reasons can be identified – lifetime and emission-intensive materials. Lifetimes of components and services have a crucial impact and must be defined clearly. Especially windows and building services have short individual lifetimes and require replacement when considering the entire building\'s lifetime. The use of the same material or unit may lead to an overestimation of emissions. However, the prediction and application of ´better´ future products and lower emissions due to improved production and a de-carbonised energy supply appears problematic. More important might be the handling of the replaced items. Cradle-to-gate conditions do not allow an appropriate treatment in this case.

The adoption of Phase Change Materials (PCMs) in building components is an up-to-date topic and a relevant number of research activities on this issue are currently on the way. A particular application of PCMs in the building envelope focuses on the integration of such a kind of material into transparent envelope components. A numerical model that describes the thermo-physical behaviour of a PCM layer in combination with other transparent materials (i.e. glass panes) has been developed to perform numerical analyses on various PCM glazing systems configurations. The paper illustrates the structure of the model, the main equations implemented and the hypotheses adopted for the model development. The comparison between numerical simulations and experimental data of a simple PCM glazing configuration is also presented to show the potentials and the limitations of the numerical model. While a good agreement between simulations and experimental data can be shown for the surface temperature of the glazing, the comparison between simulated and measured transmitted irradiances and heat fluxes does not always reach the desired accuracy. However, the numerical tool seems to predict well the thermo-physical behaviour of the system and may therefore represent a good starting point for further simulations on PCM glazing system configurations.

The building enclosure plays a relevant role in the management of the energy flows in buildings and in the exploitation of the solar energy at building scale. An optimized configuration of the façade can contribute to reduce the total energy demand of the building. Traditionally, the search for the optimal façade configuration is obtained by analyzing the heating demand and/or the cooling demand only, while the implication of the façade configuration on the energy demand for artificial lighting is often not considered, especially during the first stage of the design process. A global approach (i.e. including heating, cooling and artificial lighting energy demand) is instead necessary to reduce the total energy need of the building. When considering the total energy use in building, the optimization of a façade configuration becomes not straightforward, because non-linear relationships often occur. The paper presents a methodology and the results of the search of the optimal transparent percentage of a façade module for office buildings. The investigation is carried out for the four main orientations, on three "average" office buildings (with different surface-area-to-volume ratio), and with different HVAC system's efficiency, located in Frankfurt. The results show that the optimal configuration, regardless of the orientations and the surface-area-to-volume ratio, is achieved in an "average" office building when the transparent component of the façade module is between 35% and 45% of the total façade module surface. The north-exposed façade is the one that presents the highest difference between the "optimal configuration" and the worst one, while the south-exposed façade is the one which suffers less in case of the "worst" configuration.

Zero emission buildings (ZEB) are buildings with a minimized energy consumption and renewable energy supply with zero greenhouse gas emissions. There is no common accepted definition of zero emission buildings. This is due to issues in defining the boundary of a balance in terms of building site and time frame of this balance. Further, there is no standard on accounting for emissions (on material, components, system, and building level) nor is there a standard for emissions from other building related environments. In this paper the goals for ZEB are specified and implications for components are discussed.

The adoption of Phase Change Materials (PCMs) in building components is an up-to-date topic and a relevant number of research activities on this issue is currently on the way. A particular application of PCMs in the building envelope focuses on the integration of such a kind of material into transparent envelope components. A numerical model that describes the thermo-physical behaviour of a PCM layer in combination with other transparent materials (i.e. glass panes) is developed to perform numerical analyses on various PCM glazing systems configurations. The paper illustrates the structure of the model, the main equations implemented and the hypotheses adopted for the model development. The comparison between numerical simulations and experimental data of a simple PCM glazing configuration is also presented to show the potentials and the limitations of the numerical model. While a good agreement between simulations and experimental data can be shown for the surface temperature of the glazing, the comparison between simulated and measured transmitted irradiances and heat fluxes does not always reach the desired accuracy. However, the numerical tool seems to predict well the thermo-physical behaviour of the system and may therefore represent a good starting point for simulations on different configurations of PCM glazing systems.