Kvarteret Kajutan - Från lågenergi till plusenergi
Energy and environmental demands regarding buildings have become an increasinglydiscussed topic, both in Sweden and in Europe as a whole. The general trend indicatesthat greater efforts are being put into the energy efficiency of the built environment.There are already numerous examples of houses with a low energy demand, and thenumber of low energy buildings is constantly growing.At the time being, the maximum level for energy demands for housing in Stockholm is110 kWh/m2year, but as soon as next year the limit will be changed to 90. The Swedishagency Energimyndigheten is currently conducting a project to interpret the EU Directiveon the so-called Nearly zero energy buildings, and the preliminary results indicate thatthe level of requirements for purchased energy will end up with about 55 kWh / m2year,which is in line withtoday?s recommendationsfound in FEBY's Kravspecifikation förPassivhus.Starting with a low-energy house in Henriksdalshamnen in Stockholm, we have analyzedvarious energy-efficiency measures and their influence on power and energy needs. Thefinancial aspects associated with the measures have been studied using a model of lifecycle costs.The measures were initially studied individually to give an idea of how much impact theyeach had. Three packages of measures were then put together, where the most energyandcost-effective solutions were included.The first package of measures aimed to achieve the standard for Passive houses, and wasaccomplished by the replacement of windows and an improvement in airtightness. Theeconomic analysis showed that this package was not viable. The second package ofmeasures aimed to as much as possible reduce the building's energy needs and at thesame time demonstrate profitability. The results showed a more than halved energydemand and the economic calculations indicated that it even turned a profit.Finally, the possibility of installing energy-producing systems in order to achieve a plusenergy house was studied. The idea was to examine whether it was possible to cover upthe need for purchased energy by using solar and wind power, while maintainingprofitability. The analysis shows that this would be difficult to achieve, primarily becauseof the high investment costs entailed, and the difficulties associated with the regulationsregarding the sale of energy.