IEA EBC Annex83 positive energy districts

At a global level, the need for energy efficiency and an increased share of renewable energy sources is evident, as is the crucial role of cities due to the rapid urbanization rate. As a consequence of this, the research work related to Positive Energy Districts (PED) has accelerated in recent years. A common shared definition, as well as technological approaches or methodological issues related to PEDs are still unclear in this development and a global scientific discussion is needed. The International Energy Agency’s Energy in Buildings and Communities Programme (IEA EBC) Annex 83 is the main platform for this international scientific debate and research. This paper describes the challenges of PEDs and the issues that are open for discussions and how the Annex 83 is planned and organized to facilitate this and to actively steer the development of PEDs major leaps forward. The main topics of discussion in the PED context are the role and importance of definitions of PEDs, virtual and geographical boundaries in PEDs, the role of different stakeholders, evaluation approaches, and the learnings of realized PED projects

Vacuum insulation panels in wood frame wall constructions with different stud profiles

In this work, the thermal performance of three different wall configurations was examined by hot box measurements and numerical simulations. Vacuum insulation panels were sandwiched between traditional insulation in walls where the load-bearing elements were standard 36-mm-thick wooden studs, I-profiled studs and U-profiled studs. The measured mean values of the thermal transmittance (U-value) were 0.09 W/m2·K with 36-mm-thick wooden studs, 0.10 W/m2·K with U-profiled studs and 0.11 W/m2·K with I-profiled studs. The comparison of the three wall structures has shown that with such low U-values, the numerical simulations are more sensitive to the accuracy of the dimensions and thermal conductivities used as input. This required measurements of the thermal resistance of the fibreboard in two directions, the thickness and thermal resistance of the vacuum insulation panels and the thermal resistance of the 36-mm-thick wooden studs and the mineral wool.ACKNOWLEDGEMENTS. This work has been supported by the Research Council of Norway, AF Gruppen, Glava, Hunton Fiber as, Icopal, Isola, Jackon, Maxit, Moelven ByggModul, Rambøll, Skanska, Statsbygg and Takprodusentenes forskningsgruppe through the SINTEF and NTNU research project ”Robust Envelope Construction Details for Buildings of the 21st Century ” (ROBUST). The company va-Q-tec, by Roland Caps, is acknowledged for supplying the vacuum insulation panel test samples.acceptedVersio