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Natural ventilation is a commonly used principle when ventilation systems for buildings are designed. The ventilation can either be obtained by automatically controlled openings in the building envelope, or it can just be the simple action of opening a door or a window to let the fresh air in. In both situations the aim is to obtain a good indoor environment but to control the amount of air, some basic knowledge of the flow through an opening is necessary. The amount of air going through the window opening in single-sided ventilation will depend on the wind speed near the building, the temperatures inside and outside the room, the wind direction, the turbulence characteristics in the wind and the pressure variations caused by e.g. wind gusts. Finally it also depends on the size, type and location of the opening. Therefore, expressions for this prediction mainly depend on unsteady parameters, which make the prediction difficult. From earlier work, a few design expressions for single-sided ventilation already exist, but none of these include the wind direction, which here is an important parameter. Therefore several wind tunnel experiments are made in this work to find a new design expression which includes all of the above parameters.

Natural ventilation is a commonly used principle when buildings are being ventilated. It can be controlled by openings in the building envelope, which open or close depending on the need of air inside the building. It can also be the simple action of just opening a door or a window to let the fresh air in. In both cases it is often necessary to have an idea of the amount of air coming through the window. Therefore, expressions for this prediction have been developed through the last decades. In cross-ventilation, the expressions are rather well defined and here the difficulty lies within the definition of the discharge coefficient that describes the characteristics of the opening, since it seems to fluctuate depending on the incidence angle of the wind. In single-sided ventilation where openings only exist in one side of the building, the flow through the opening is harder to predict. The main driving forces are still wind pressure and temperature differences as with cross-ventilation, but here the turbulence in the wind and the pulsating flow near the opening also affect the flow through the opening. From earlier work, some design expressions already exist, but none of these include the incidence angle of the wind, which is an important parameter in this type of ventilation. Several wind tunnel experiments are made and from the results of these, a new design expression is made which includes the wind pressure, temperature difference, incidence angle of the wind and the fluctuations in pressure at the opening. A discussion is made regarding the correctness of using wind tunnel measurements for a design expression to be used outdoors, but here it is concluded from analysis of the different types of wind that this can be done with some knowledge of the differences. Finally, the new expression is compared to results found from outdoor fullscale measurements with good agreement. Natural ventilation is a commonly used principle when buildings are being ventilated. It can be controlled by openings in the building envelope, which open or close depending on the need of air inside the building. It can also be the simple action of just opening a door or a window to let the fresh air in. In both cases it is often necessary to have an idea of the amount of air coming through the window. Therefore, expressions for this prediction have been developed through the last decades. In cross-ventilation, the expressions are rather well defined and here the difficulty lies within the definition of the discharge coefficient that describes the characteristics of the opening, since it seems to fluctuate depending on the incidence angle of the wind. In single-sided ventilation where openings only exist in one side of the building, the flow through the opening is harder to predict. The main driving forces are still wind pressure and temperature differences as with cross-ventilation, but here the turbulence in the wind and the pulsating flow near the opening also affect the flow through the opening. From earlier work, some design expressions already exist, but none of these include the incidence angle of the wind, which is an important parameter in this type of ventilation. Several wind tunnel experiments are made and from the results of these, a new design expression is made which includes the wind pressure, temperature difference, incidence angle of the wind and the fluctuations in pressure at the opening. A discussion is made regarding the correctness of using wind tunnel measurements for a design expression to be used outdoors, but here it is concluded from analysis of the different types of wind that this can be done with some knowledge of the differences. Finally, the new expression is compared to results found from outdoor fullscale measurements with good agreement.

Denne rapport er udarbejdet i forbindelse med måleprogrammet for kontorbygningen Københavns Energi. Måledata anvendes til at dokumentere ventilationsanlæggets funktion og ydeevne med hensyn til termisk indeklima, atmosfærisk indeklima, luftskifte og luftfordeling. Målingerne gennemføres i perioden juli 2005 - juni 2006. Denne rapport er udarbejdet i forbindelse med måleprogrammet for kontorbygningen Københavns Energi. Måledata anvendes til at dokumentere ventilationsanlæggets funktion og ydeevne med hensyn til termisk indeklima, atmosfærisk indeklima, luftskifte og luftfordeling. Målingerne gennemføres i perioden juli 2005 - juni 2006.

This project aims at testing technologies for control of heat transfer, irradiation, mass transport and energy storage in order to investigate the potential of a intelligent dynamic glazed facade. Furthermore a development of algorithms for control of the technologies included in the facade, for use in the design phase, is done. The methods used are initially based on thermal building calculations. This analysis shows that a dynamic adaptive facade is the only way in which future office buildings can fulfil the energy regulations. By designing the facade according to the usage and the microclimate, the energy usage of the building can be lowered significantly and fulfil energy regulations for 2020. This project aims at testing technologies for control of heat transfer, irradiation, mass transport and energy storage in order to investigate the potential of a intelligent dynamic glazed facade. Furthermore a development of algorithms for control of the technologies included in the facade, for use in the design phase, is done. The methods used are initially based on thermal building calculations. This analysis shows that a dynamic adaptive facade is the only way in which future office buildings can fulfil the energy regulations. By designing the facade according to the usage and the microclimate, the energy usage of the building can be lowered significantly and fulfil energy regulations for 2020.

Paperet præsenterer resultater fra både kvalitative og kvantitative undersøgelser af indeklimaet i projektet Komfort Husene. Husene er nogle af de først certificerede passivhuse i Danmark. Den kvantitative evaluering udføres på baggrund af målinger af husenes indeklima, hvor den kvalitative evaluering udføres på baggrund af semi-strukturerede forskningsinterview med beboerne i husene. Resultaterne sammenlignes for at undersøge, om der er uoverensstemmelser mellem de to metoder, men også for at give et mere udførligt billede af indeklimaet, hvor de kvalitative interview kan bruges som årsagsforklaring af målingerne. Resultaterne viser, at både det termiske og atmosfæriske indeklima kan og skal forbedres for at beboerne oplever komfort. For at opnå dette, er det vigtigt at have indeklimaet for øje gennem hele projektet, både i skitserings-, projekterings- og udførelsesfasen. Derudover er information og oplæring af beboerne efterfølgende også vigtig.

This paper is the initial result of a cross-disciplinary attempt to encircle an answer to the question of optimal densities of sustainable settlements. Urban density is an important component in the framework of sustainable development and influences not only the character and design of cities but also the architectural and technical strategies of buildings. The paper is based on literature studies in the fields of urban mobility, urban ecology, urban design, architecture and civil engineering. It concludes that neither detached houses nor extremely dense cities are optimal answers to the sustainable challenge. This paper is the initial result of a cross-disciplinary attempt to encircle an answer to the question of optimal densities of sustainable settlements. Urban density is an important component in the framework of sustainable development and influences not only the character and design of cities but also the architectural and technical strategies of buildings. The paper is based on literature studies in the fields of urban mobility, urban ecology, urban design, architecture and civil engineering. It concludes that neither detached houses nor extremely dense cities are optimal answers to the sustainable challenge.