Time filter

Source Type

Andersen P.D.,Technical University of Denmark | Iversen A.,Danish Building Research Institute | Madsen H.,Technical University of Denmark | Rode C.,Technical University of Denmark
Energy and Buildings | Year: 2014

Occupancy modeling is a necessary step towards reliable simulation of energy consumption in buildings. This paper outlines a method for fitting recordings of presence of occupants and simulation of single-person to multiple-persons office environments. The method includes modeling of dependence on time of day, and by use of a filter of the observations it is able to capture per-employee sequence dynamics. Simulations using this method are compared with simulations using homogeneous Markov chains and show far better ability to reproduce key properties of the data. The method is based on inhomogeneous Markov chains with where the transition probabilities are estimated using generalized linear models with polynomials, B-splines, and a filter of passed observations as inputs. For treating the dispersion of the data series, a hierarchical model structure is used where one model is for low presence rate, and another is for high presence rate. © 2013 Elsevier B.V. All rights reserved.

Laverge J.,Ghent University | Spilak M.,Danish Building Research Institute | Novoselac A.,University of Texas at Austin
Building and Environment | Year: 2014

In exposure studies and risk assessments, the intake of a pollutant through inhalation is often estimated using the well mixed concentration in the room. Less traditional ventilation systems such as stratum ventilation, displacement ventilation or personal ventilation systems aim to achieve higher ventilation effectiveness by delivering supply air directly in the occupants' vicinity, thus creating flow conditions that divert from the well mixed condition. Also, with sources in the near proximity of occupants, the concentration in the occupants breathing zone is often much higher than the one predicted assuming well mixed conditions, and assessment of exposure often requires calculation of pollutant concentrations in the inhalation zone. In this paper, we present the results of experiments with a breathing thermal manikin in an environmental chamber that define the geometrical extend of the inhalation zone of standing, sitting and sleeping persons breathing through the nose. These results allow to determine the inhaled fraction of a near field source of a gaseous pollutant and determine a geometrical zone around the nose where the intake fraction is equal to 1 as a reference for the selection of sampling positions in exposure studies. The experiments show that a person's thermal plume has a large impact on the shape of the inhalation zone, limiting the inhalation zone of standing and sitting persons to the area situated almost directly under the nose. For a sleeping person, the breathing zone is stretched down along the cheeks due to this same effect. The transient effect of the breathing cycle has only a minor influence on the inhalation zone. © 2014 Elsevier Ltd.

Jensen J.O.,Danish Building Research Institute | Jorgensen M.S.,Technical University of Denmark | Elle M.,Technical University of Denmark | Lauridsen E.H.,Technical University of Denmark
Sustainability: Science, Practice, and Policy | Year: 2012

Sustainable buildings have often been niche products, but in recent years a new approach has emerged in Denmark aimed at mainstreaming and normalizing this mode of construction and seeking to attract ordinary Danes through market conditions. The aim is to present an alternative conceptualization of sustainable buildings to the ecocommuni-ties' vision and to involve traditional building firms in their design and development. From a theoretical perspective, the mainstreaming of sustainable buildings can be seen either as an example of ecological modernization or techno-logical transition. The new conceptualization has implied a narrower approach to sustainability and a lack of social sustainability measures. While earlier paradigms of sustainable buildings emphasized themes such as community building, self-provisioning, local empowerment, and shared facilities, such objectives are largely absent in the new types of sustainable buildings. We question to what extent it is possible to design sustainable settlements without social sustainability. By viewing sustainable buildings as technological configurations, we argue that the multiactor approach, fragmentation of roles, and absent initiatives for social sustainability influence the buildings' environmental performance and should be important for the next generation of these structures. © 2012 Jensen et al.

Andersen H.S.,Danish Building Research Institute
Housing Studies | Year: 2010

In most European countries ethnic minorities have had a tendency to settle in certain parts of cities-and often in social housing-together with other immigrants in so-called multiethnic neighbourhoods. An explanation for this could be low income combined with lack of knowledge of the housing market and discrimination, which limits the housing possibilities for ethnic minorities. Another explanation could be that for different reasons immigrants choose to settle in so-called ethnic enclaves where they can find an ethnic social network, which can support them in their new country. In traditional research literature about immigration it has been shown that for many immigrants living in enclaves has been a temporary situation. The 'spatial assimilation theory' says that this situation ends when the family has become more integrated in the new society and then moves to another part of the city. This paper provides evidence to support both explanations of why ethnic minorities move to and from multi-ethnic neighbourhoods. © 2010 Taylor & Francis.

Brauner E.V.,Danish Cancer Society | Mayer P.,University of Aarhus | Gunnarsen L.,Danish Building Research Institute | Vorkamp K.,University of Aarhus | Raaschou-Nielsen O.,Danish Cancer Society
Journal of Environmental Monitoring | Year: 2011

Organochlorine pesticides are present in the environment and suspected of causing serious health effects. Diet has been the main exposure source, but indoor source release is gaining focus. Within a monitoring study of polychlorinated biphenyls of Danish buildings built during the 1960s and 1970s, we coincidently determined extreme levels of dichlorodiphenyltrichloroethane (DDT) levels in two of ten random samples. This raises concern and further large scale investigations are warranted to confirm this. © 2011 The Royal Society of Chemistry.

Discover hidden collaborations