Primary energy consumption was 77 kWh/(m2NFAa) (Rislerstrasse KfW60), 69 kWh/(m2NFAa) (Rislerstrasse KfW40), 51.8 kWh/(m2NFAa) (Freyastr) and 37 kWh/(m2NFAa) (Blaue Heimat) applying the credit method for CHP in the latter case. Thus the results are slightly above the target.

Energy consumption KfW40 2005/06 [kWfVrr^a]

80 70 60 50 40 30 20 10 0

Useful energy Site energy Primary energy

■ Heating DHW ■ Solar Auxiliary energy ■ Ventilation

Energy consumption KIW60 2005/06 [kWfv’nrVa]

The results allow the following conclusions to be drawn about the buildings and their energy

concepts:

• Energy: the targets projected during planning were reached in actual operation and even surpassed in some cases. The building standards studied can be considered state of the art even by today’s standards. Renovation can bring old buildings close to the passive house standard despite specific problems, such as ventilation, air tightness, and thermal bridges. The strict standard for the building itself means that parameters influenced by users (such as hot water consumption and ventilation) become more important, as do relatively minor energy flows (such as distribution and storage losses), which then have to be taken into greater consideration during planning. The main consumption parameters are hot water and electricity; for instance, the figures for Blaue Heimat were: heating: 18.9 kWh/(m2NFAa), hot water: 28.4 kWh/(m2NFAa), electricity: 24.3 kWh/(m2NFAa). Even though they were taken into consideration during planning, storage and distribution losses were almost half as high as the actual heating energy consumption (insulation of the distribution system in Blaue Heimat: 200 %, Rislerstrasse: installation in attic insulation)

• Supply Systems: thermal solar collectors make a significant contribution. If storage is properly dimensioned, a cogeneration unit can run at very high capacity utilization rates, thereby functioning as an efficient supply system after renovation and being an important part of a net zero energy strategy.

• Users: A comparison of heating energy consumption in the buildings in Rislerstrasse revealed only a slight difference between the two energy standards, which was not projected. The reasons may be the influence of user behaviour (comfort requirements and ventilation), a difference in the number of people in the buildings, or less efficient heat recovery in the ventilation system.

This assessment and analysis as part of IEA SHC TASK 37 received funding from the German

Ministry of Economics and Technology — BMWi (reference number: BMWi 0327271B).

References

[1] Salvesen, F. : Advanced Renovation with Solar and Conservation, Proc. of EUROSUN 2008, Lisbon

[2] Hastings, R. : Advanced Solar Renovation, Keynote at EUROSUN 2008, Lisbon, www. iea-task37.org

[3] Voss; K., Kramp, M.: Zero-Energy/Emission-Building: Terms, Definitions and Building Practice, CESB Conference, Prague, 24.-25. September 2007, proceedings vol. 2, p. 547ff

[4] Projektrager Julich: www. enob. info

[5] Deutsche Energieagentur dena: www. neh-im-bestand. de (in German)

[6] Reiss, J.; Erhorn, H.: Bauliche Konzeptentwicklung fur eine 3-Liter-Reihenhauszeile im Rahmen von ModernisierungsmaBnahmen in Mannheim-Gartenstadt. Bauphysik 26 (2004), Heft 6, p. 322-334

[7] Ufheil, M.; Sanierung Blaue Heimat, 9. Passivhaustagung Ludwigshafen (in German)

[8] Zaman, A.: Passivhaus im Bestand Hoheloogstr. 10. Passivhaustagung Hannover 2006 (in German)

[9] Kagerer, F.; Herkel, S.: Versorgungsstrategien in der Wohnbausanierung, OTTI Tagung Sanierung 14.2.2008 (in German)

[10] Schmidt, M.; Schmidt, S.; Treiber, M.; Arold, J.: Schlussbericht „Energetische Modernisierung kleiner Wohngebaude auf 3-Liter-Haus-Niveau in Mannheim“, Lehrstuhl Klimatechnik, Uni Stuttgart, 2007