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Abstract: The indoor climate was evaluated in a cubicle office of the first office building with passive house standard in Norway. The office building (http://miljohuset-gk.no/) is located in Oslo and operational since August 2012. In this building, demand controlled ventilation is used to cover the heating demand by supplying warm ventilation air into the rooms when needed. The purpose of this study is to determine whether this strategy provides a good thermal comfort and ventilation effectiveness, and therefore constitutes a relevant solution for buildings with low heating demand. Measurements were carried out in the cubicle office during the coldest days of winter 2013-2014, and revealed a good indoor climate for a broad range of supplying and heat load conditions.

Abstract: The future is well-isolated buildings with low heating demand. The first office building in Norway satisfying the passive house standard, the GK environmental house in Oslo, was taken into use in August 2012. Low energy building is the standard for new buildings according to the building codes today, and since passive house standard seems to be included in the building codes in Norway from 2015 there is a great change in the building industry. To meet the low energy concept, the ventilation industry must cope with a massive change from use of installations with constant air volume (CAV) to demand controlled ventilation. At the same time new technology with active air handling units makes new ventilation systems more flexible to demand controlled ventilation and temperature control, air velocity and draft. The low heating demand in future buildings address the question – is it possible to use simplified heating systems, or even only air heating without any backup heating system, also for the coldest days in Norway and still have satisfied users? However, given the cold climate in Norway, totally eliminating a backup heating system for the coldest days and only use overheated supply air would be a tough decision without proper documentation. The R & D project “Simplified demand controlled air conditioning in office buildings with very low heating demand” will develop concepts for ventilation based space heating fit to buildings with very low heating demand, as well as develop documentation on the function and the conditions that must be fulfilled. (www.sintef.no/projectweb/For-Klima). The project period is three years, starting 2013. This paper reviews the results so far. So far a broad range of studies have been done: Field measurements and intervention studies with user survey on perceived indoor climate at GK environmental house, laboratory measurements, calculations and theoretical evaluations. This paper discusses the results so far after the first winter period. These are preliminary results that will have to be confirmed by further studies next winter.

Abstract: The impact of over-tempered air on the perceived indoor climate was evaluated by questionnaires filled in by the users of the first office building with passive house standard in Norway. In this building, the heating demand is covered entirely by warm air supplied into the rooms through the ventilation system. On the coldest days of January 2014, warm ventilation air was supplied into the rooms at a constant temperature during half an hour. Each user of the building was exposed to 3 different supply temperatures (around 21.5°C, 24°C and 26°C) under the minimum ventilation rate according to the Norwegian standards (17 l/s). Questions related to both perceived thermal comfort and Sick Building Syndrome-symptoms (SBS; feeling tired, headache, etc.) were answered by all the occupants on a scale of 0 (unsatisfied) to 10 (satisfied). The data from the questionnaires were then analyzed using a random effect linear regression model. The regression analysis did not report any significant relationship between the supply air temperature, and perceived thermal comfort and SBS. It enables to document with a 95% certainty that increasing the difference between supply air and room temperature by 1°C would cause a maximum reduction of the SBS score of 1.02 points on a scale of 190. The impact of an increase of the supply temperature on the perceived SBS seems therefore very limited. Using air heating to completely cover the heating demand therefore appears to be a relevant solution for office buildings in cold climate with passive house standard.

Abstract: The Marienlyst School is the first educational building in Norway built according to the passive house standard. This building benefits from a super-insulated and airtight envelope. While this reduces the heating demand largely, it also enhances the risk for poor indoor air quality and overheating compared to conventional buildings. It is therefore particularly important to implement an efficient ventilation strategy in order to avoid adverse effects on the health, well-being and productivity of the pupils. In this context, the perceived indoor climate resulting from two different ventilation control strategies was evaluated in one classroom of the building. Both strategies consisted in varying the ventilation rate according to room demand, ie. Demand Controlled Ventilation (DCV). The existing strategy consisted in varying the ventilation rate in order to maintain a constant carbon dioxide concentration of 800 ppm in the classroom. A new strategy was implemented which consisted in a combined CO₂ and temperature DCV, ie. to control towards a proportionally lower CO₂ concentration when the indoor temperature increased. The aim with this strategy was to address both overheating and the fact that perceived indoor air quality decreases when temperature rises. Indoor climate measurements, as well as questionnaires on the perceived indoor air quality and thermal comfort filled up by the pupils were used to compare both strategies. The data from the questionnaires were then analyzed using a random effect linear regression model. The regression analysis revealed that the initial ventilation strategy was responsible for discomfort resulting from too high variations in the indoor temperature. The new combined CO₂ and temperature DCV strategy provided a perceived indoor climate which was significantly better than the existing strategy. Therefore, the developed ventilation strategy appears to be a relevant solution in order to address the problem of overheating and perceived indoor air quality in educational buildings with passive house standard.

Abstract: In this article we compare to ventilation strategies to heat a “passive house” office building using only the ventilation system. Two ventilation strategies with supply air temperature above and below the current room temperature were compared through a cross over experiment. A questionnaire was used to measure the perceived health and well being. Both strategies documented very good indoor climate with highly positive scores on the questionnaire. The strategy with supply air temperature above the room temperature resulted in a little better perceived health and well being compared to the other strategy.

Abstract not available