VELUX is a Danish company that specializes in windows and skylights. The first VELUX roof window was installed in a Danish school over 60 years ago by the founder of the company, Villum Kann Rasmussen. The company has been steadily growing since, entering the German market in 1952 in a partnership with Ernst Günter Albers and then later between the sons, Lars Kann-Rasmussen and Peter AlbersIn addition, VELUX offers many types of decoration and sun screening, roller shutters, installation products, products for remote control and thermal solar panels for installation in roofs. VELUX has manufacturing companies in 10 countries and sales companies in just under 40 countries.The VELUX Group has around 10,000 employees and is run by VKR Holding A/S, a limited company wholly owned by foundations and family.The company currently sponsors the VELUX 5 Oceans Race and the EHF Champions League. Wikipedia.
Psomas T.,University of Aalborg |
Heiselberg P.,University of Aalborg |
Duer K.,VELUX |
Bjorn E.,DOVISTA A S
Energy and Buildings | Year: 2016
Many post-occupancy comfort studies of energy renovated residential buildings have documented elevated temperatures above comfort levels, not only during the summer period but also during the shoulder months. The main focus in renovation projects is on heat savings while the risk of overheating is not considered. This paper analyze in which situations overheating and cooling need to be addressed in building energy renovation projects and which renovation measures are causing this need. The analysis contains four reference single family houses from central and northern Europe. Both dynamic and static methods were used to assess the overheating risk. In terms of overheating occurrences, the most critical renovation measures are the insulation of the floor and the increase of the airtightness. The contribution of decreasing the g value of the window glazing is positive. The way to energy efficiency improvements also results in an extension of the overheating period and higher average and maximum building temperatures. The increase of the ventilation rates and the use of shading systems are useful measures for preventing overheating increase. The paper will highlight the inconsistencies which arise from the use of different criteria and also propose suggestions for future work. © 2016 Elsevier B.V. All rights reserved.
Mardaljevic J.,Loughborough University |
Lighting Research and Technology | Year: 2016
This paper describes a fundamental rethinking of the basis for the evaluation of the sunlight potential of spaces. It provides a robust methodology to answer the question: how much sunlight can enter a room? The measure proposed is the cross-sectional area of beam sunlight that passes through a window. The new measure - called the sunlight beam index - is described, and examples are given for a realistic residential dwelling. The sunlight beam index is determined for a full year on a time-step basis (e.g. every 15 minutes), but it can be aggregated into monthly or yearly totals. The annual total provides a single measure for one window, a group of windows or all the windows for an entire dwelling. © SAGE Publications.
Hansen E.K.,University of Aalborg |
Hammershoj Olesen G.G.,University of Aalborg |
Hammershoj Olesen G.G.,VELUX |
Mullins M.,University of Aalborg
Proceedings of the IEEE | Year: 2013
This paper focuses on how smart technologies integrated in a one-family home, and particularly a window, offer unique challenges and opportunities for designing buildings with the best possible environments for people and nature. Toward an interdisciplinary and multidimensional approach, we address the interaction between daylight defined in technical terms and daylight defined in aesthetic, architectural terms. Through field tests of a Danish carbon-neutral home and an analysis of five key design parameters, we explore the contradictions and potentials in smart buildings, using the smart window as an example of how quality of life and technical advances are synthesized and when they contradict. We focus on the need to define quantitative and qualitative values and synthesize these in a multidimensional design approach, toward allowing the house to adapt to a changing climate, satisfy the human needs of the occupants, together with meeting calculated energy requirements. Thus, integrating windows as key design elements in energy-positive buildings addresses aesthetic as well as technical potentials. This integration of factors from different fields can both support and counterbalance one another in the design process. We maintain that a hybrid approach to the energy design is central. The study illuminates an approach of the design of smart houses as living organisms by connecting technology with the needs of the occupants with the power and beauty of daylight. © 1963-2012 IEEE.
Markvart J.,University of Aalborg |
Hansen A.M.,Copenhagen University |
LEUKOS - Journal of Illuminating Engineering Society of North America | Year: 2015
Measurement of personal light exposures and activity has gained popularity in studies of the circadian rhythm and its effects on human health. Calibration of a batch of measuring devices may be needed, especially before initiating interventional studies, but manufactory calibration of devices before every initiated study is costly for the researcher and therefore often left out. Still, knowledge of inter-equipment variability is essential and seldom provided by the manufactory. The aim of the present study was to develop and test a method for field calibration of Actiwatch Spectrum devices. We tested 48 Actiwatch devices side by side under various light sources and present the red, green, blue, and white light response variability among the Actiwatches. The influence of different spatial and spectral light environments on the white light response when compared with the output from a calibrated photometer is discussed. In agreement with previous studies by Price and others  and Figueiro and others , we confirm the devices white light responses to be highly dependent on both the spatial and the spectral composition of the light. The white light response represents photopic illuminance only to a minor degree and light source-specific calibration may therefore be needed in some cases. Moreover, light responses were found to vary between devices by up to 60%. Implications are that the results of light effects on health issues in studies using Actiwatches are blurred by the equipment variability. To compensate for inter-equipment variability we stress the need for a field calibration procedure. When light exposure devices of lower grade quality are used in spectrally and spatially changing light environments, daylight from a diffused overcast sky is suggested to be used for side-by-side calibration of Actiwatches and similar personal light exposure devices.We suggest that the calibration methods presented can be used for calibration of other practical field devices, with respect to the various sensors already on the market and devices that will be introduced in the future. © Copyright lluminating Engineering Society.
Logadottir A.,University of Aalborg |
Christoffersen J.,University of Aalborg |
Christoffersen J.,VELUX |
Fotios S.A.,University of Sheffield
Lighting Research and Technology | Year: 2011
An experiment was carried out to examine user preferences for light level using the method of adjustment. The study sought preferred illuminances under lighting from fluorescent lamps of different correlated colour temperature. It was hypothesised that the preferred illuminance would be influenced by variables inherent in the experimental design including the available stimulus range, the anchor (initial setting before adjustment) and adaptation time before onset of adjustment action. The experiment included three different stimulus ranges (21-482 lux, 38-906 lux and 72-1307 lux) and these lead to significantly different preferred illuminances (337 lux, 523 lux and 645 lux, respectively). The experimental results confirmed that stimulus range and anchor have significant effects on the outcome of the adjustment task, confirming the importance of considering and reporting these variables when determining user preference with this method. © The Chartered Institution of Building Services Engineers 2011.