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Prospects for the modernisation of existing buildings using highly efficient components
This article (based on a contribution to the 24th Session of the Research Group for Cost-effective Passive Houses [Feist 2003] focuses on the use of highly energy-efficient building components for the modernisation of existing buildings. Originally, these components were developed for use in new constructions. In order to make full use of innovative technology like compact heat pump units for example, a high standard of thermal protection, increased airtightness and efficient ventilation are essential. Achieving the Passive House limit (heating load smaller than 10W/m²) in new constructions therefore justifies the use of particularly efficient components. For this reason, an increasing range of such building components has been developed in recent years. As demonstrated by a number of examples, in the case of existing buildings it is usually not possible to achieve the Passive House Standard at reasonable cost by means of the procedures and technology available today. However, this may not even be necessary in the case of modernisations, as the apartments and commercial spaces involved usually have a functioning heat distribution system (usually based on hot water pump heating) and there isn’t any reason why the existing system cannot continue to be used. On the contrary, the existing heating surfaces are over-sized in any case as a rule, and if the heating demand is further reduced due to modernisation, the design temperatures can be decreased considerably. This in turn leads to a reduction in the distribution losses and enables the efficient use of heat generation variants like condensing boilers and heat pumps with a high degree of utilisation. Such an approach also requires significant improvement of the building envelope and the ventilation technology as well as efficient heating technology.
Based on the examples dealt with in the 24th session of the Research Group for Cost-effective Passive Houses [AkkP 24], Passive House components are also suitable for the modernisation of existing buildings. Their application is both practicable and cost-effective.
• offer greater security against moisture-related damage,
• improve thermal comfort due to higher surface temperatures
• and double the potential for accessible energy savings.
The attractiveness of a high quality standard of modernisation increases with the use of highly efficient components, as the quality of life of the occupants is improved perceptibly. On the other hand, modernisation measures for existing buildings are an important means for stimulating the economy. Thus the measures discussed here represent one of the crucial areas in which economic growth can take place while at the same time relieving the environmental burden. With the measures presented here, it is possible to achieve a considerable reduction in CO2 emissions. Improved efficiency in this sector means reduced consumption which enables an increase in the sensible use of renewable energy sources. Other demonstration projects of the energy-efficient modernisation of buildings have been started recently. Avoiding the mistakes of the past by means of thermal bridge free design and effective home ventilation, implementation on a wider scale is only a question of motivation.
[AkkP 24] Einsatz von Passivhaustechnologien bei der Altbau-Modernisierung, Protokollband Nr. 23 des Arbeits¬kreises kosten¬günstige Passivhäuser Phase III; Passivhaus Institut; Darmstadt, 2003.
Refurbishment with Passive House components, Protocol Volume No. 23 of the Research Group for Cost-effective Passive Houses, Phase III; Passive House Institute; Darmstadt, 2003.
[AkkP 23] Einfluss der Lüftungsstrategie auf die Schadstoff¬konzentration und –ausbreitung im Raum, Protokollband Nr. 23 des Arbeits¬kreises kosten¬günstige Passivhäuser Phase III; Passivhaus Institut; Darmstadt, 2003.
Influence of the ventilation strategy on the concentration and distribution of harmful substances in rooms, Protocol Volume No. 23 of the Research Group for Cost-effective Passive Houses Phase III; Passive House Institute; Darmstadt, 2003.
[Feist 1999] Feist, W.: Anforderungen an die Wohnungslüftung im Passivhaus, in: Arbeitskreis kostengünstige Passivhäuser, Protocol Volume No. 17, 1. Auflage, Darmstadt, 1999.
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[Feist 2000] Feist, W.: Förderkonzept Gebäudebestands-Modernisierung, im Auftrag der Initiative „Jetzt!“; 1. Auflage, Passivhaus Institut, Darmstadt, 2000.
Feist, W.: Funding concept ort he modernisation of existing building stock, on behalf of the „Jetzt!“ Initiative; 1st edition, Passive House Institute, Darmstadt, 2000.
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Hauser, G. et al.: Thermal bridges in existing buildings, HEA-Research Group “Building physics”, Frankfurt, 2001.
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[Simons 2000] Simons, P.: Fachwerksanierung mit 12 cm Innendämmung; Vierjährige Messungen zum feuchtetechnischen Verhalten, Quadriga 1/2000, S. 39ff. Simons, P.: Refurbishment of half-timbered construction using 12cm interior insulation; Measurement of moisture-related behaviour over a four-year period, Quadriga 1/2000, page 39ff.