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Cao G.,VTT Technical Research Center of Finland | Kurnitski J.,Sitra | Awbi H.,University of Reading | Larsen T.S.,Center for Construction and Business | And 5 more authors.
10th International Conference on Healthy Buildings 2012 | Year: 2012

Indoor environmental quality and energy performance of buildings are becoming more and more important in the design and construction of low energy, passive and zero energy buildings. At the same time, improved insulation and air tightness have the potential to resulting in a deterioration of the indoor air quality in such buildings. Currently, there are no global guidelines for specifying the indoor thermal environment in such low-energy buildings. The objective of this paper is to analyse the classification of indoor thermal comfort levels and recommended ventilation rates for different low energy buildings, and propose a set of indices that would enable better quantification and comparison among low energy buildings. In this study, the building codes and voluntary guidelines have been reviewed on the basis of experience of Finland, UK, Denmark, USA and Germany. The analysis in this paper will be based on the international standard ISO 7730 and EN 15251 in comparisons with other national building codes or standards. Source


Kurnitski J.,Sitra | Saari A.,Aalto University | Kalamees T.,Tallinn University of Technology | Vuolle M.,Equa Simulation Finland Oy | And 2 more authors.
Energy and Buildings | Year: 2011

This study determined cost optimal and nearly zero energy building (nZEB) energy performance levels following the REHVA definition and energy calculation methodology for nZEB national implementation. Cost optimal performance levels - meaning the energy performance leading to minimum life cycle cost - were calculated with net present value method according to the cost optimal draft regulation. The seven-step procedure was developed to conduct cost optimal and nZEB energy performance levels calculations in systematic and robust scientific fashion. It was shown that cost optimal primary energy use can be calculated with limited number of energy simulations as only four construction concepts were simulated and cost calculated. The procedure includes the specification of building envelope components based on specific heat loss coefficient and systems calculation with post processing of energy simulation results, without the need to use iterative approach or optimization algorithm. Model calculations were conducted for Estonian reference detached house to analyse the difference between the cost optimal and nZEB energy performance levels. Cost optimal energy performance level of Estonian reference detached house was 110 kW h/(m 2 a) primary energy including all energy use with domestic appliances and it was significantly lower than the current minimum requirement of 180 kW h/(m2 a). © 2011 Elsevier B.V. All rights reserved. Source


Linkola L.,Sitra | Andrews C.J.,Rutgers University | Schuetze T.,Sungkyunkwan University
Water (Switzerland) | Year: 2013

Households consume a significant fraction of total potable water production. Strategies to improve the efficiency of water use tend to emphasize technological interventions to reduce or shift water demand. Behavioral water use reduction strategies can also play an important role, but a flexible framework for exploring the "what-ifs" has not been available. This paper introduces such a framework, presenting an agent-based model of household water-consuming behavior. The model simulates hourly water-using activities of household members within a rich technological and behavioral context, calibrated with appropriate data. Illustrative experiments compare the resulting water usage of U.S. and Dutch households and their associated water-using technologies, different household types (singles, families with children, and retired couples), different water metering regimes, and educational campaigns. All else equal, Dutch and metered households use less water. Retired households use more water because they are more often at home. Water-saving educational campaigns are effective for the part of the population that is receptive. Important interactions among these factors, both technological and behavioral, highlight the value of this framework for integrated analysis of the human-technology-water system. © 2013 by the authors. Source


Barozzi S.,University of Milan | Socci M.,University of Milan | Ginocchio D.,University of Milan | Filipponi E.,Sitra | And 3 more authors.
International Tinnitus Journal | Year: 2013

Introduction: In our clinical experience, some of the patients affected by benign paroxysmal positional vertigo (BPPV) reported the onset of tinnitus shortly before or in association with the positional vertigo. Objectives: The aim of this study was to describe the prevalence and the clinical patterns of tinnitus episodes which occurred in association with BPPV and to suggest possible interpretative hypotheses. Methods: 171 normal hearing patients affected by BPPV (50 males and 122 females; age range: 25-77 years; mean age 60.3 years ± 14.9) underwent pure tone audiometry, immittance test and a clinical vestibular evaluation before and after repositioning manoeuvers. Those suffering from tinnitus were also assessed using visual analogue scales and tinnitus handicap inventory. Results: 19.3% of the patients reported the appearance of tinnitus concurrently with the onset of the positional vertigo. It was mostly unilateral, localized on the same ear as the BPPV, slight in intensity and intermittent. Tinnitus disappeared or decreased in all patients except two, either spontaneously, before performing the therapeutic manoeuvers, or shortly after. Conclusions: A possible vestibular origin of tinnitus determined by the detachment of macular debris into the ductus reuniens and cochlear duct is discussed. Source


Cao G.,Research Solutions | Cao G.,Aalto University | Ruponen M.,Halton Oy | Paavilainen R.,Halton Oy | Kurnitski J.,Sitra
Building and Environment | Year: 2011

At present, ceiling-mounted diffusers are very popular for indoor air distribution, particularly in offices, owing to greater efficiency in the distribution of the air supply and a more comfortable indoor environment. The objective of this study is to construct an effective model to design the indoor airflow of an attached plane jet after its impingement with the corner in a room. In this study, a full-scale test facility was set up to obtain detailed experimental data. One commercial CFD tool, CFX 11.0, was used to simulate the air velocity distribution of an attached plane air jet bounded by the ceiling and an insulated wall. One semi-empirical model was also constructed to predict the impingement jet velocity. The results show that bout the semi-empirical model and CFX 11.0 were able to predict the maximum velocity of an impinging jet at low Reynolds numbers, 1000 and 2000, with an inaccuracy of ±11%. However, the semi-empirical model could be more conveniently used to predict the maximum jet velocity decay after its impingement the corner in a room than CFD simulation in terms of accuracy and the time required to design the indoor airflow pattern. © 2010 Elsevier Ltd. Source

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