Ecological Rehabilitation of Panel Buildings
Brno, Czech Republic

The rehabilitation of panel buildings is one of the most pressing tasks of the construction industries in Central and Eastern Europe. Energy-efficient, environmentally sound refurbishment can decisively contribute to lowering energy needs in housing, thus reducing pollutant emissions and improving a country's balance of payments. Refurbishment projects also offer a considerable market potential for Austrian products and specialists, concluded an expert conference of the Czech-Austrian Energy Partnership on "Energy and Architecture" in Brno in October 1999.

Serial rehabilitation programs are facilitated by the high degree of standardization in prefabricated housing. Rehabilitation strategies can also be adapted with relative ease for application in the entire CEEC region, including Southeast Europe. Before large-scale rehabilitation campaigns are carried out, however, prototype rehabilitation projects are needed to furnish practical experience on technological, economic and social aspects, and to review refurbishment strategies for their ecological and economic efficiency.

Within the framework of the Czech-Austrian Energy Partnership, and in cooperation with the Austrian Energy Agency E.V.A., a team of Austrian architects - Dr. Adil LARI, Prof. Georg REINBERG and Dr. Martin TREBERSPURG - worked out strategies for the ecological and energy-efficient refurbishment of three typical panel buildings in Brno - Nový Lískovec. The study was supported by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management.

The principal idea of the study consisted in creating a flexible model for rehabilitation which can be applied to various types of prefabricated housing. The option of additional floors, to serve as an economic incentive for refurbishment, was also reviewed. Depending on the means available, the three strategies proposed can be applied in combination so as to create optimum conditions for lowering heating energy needs. According to an energy balance calculated by the University of Technology in Graz, Austria, the proposed strategies can serve to lower heating energy needs from the currently estimated 240 kWh/m²a to as little as 23 kWh/m²a.

The first strategy focuses on measures to improve the interior layout and the electro-mechanical facilities of the building. Besides basic thermal refurbishment and the improvement of the ground plan by means of minor building additions, the southern facade is equipped with plate collectors to provide indirect solar warmth, warm air, and passive solar energy for water heating purposes to the adjacent apartments. The additional floors are intended to serve communal uses (community room, sauna).

The aim of the second strategy is to provide the necessary infrastructure for ecological improvement of the building by means of a southward reorientation, without causing any inconvenience to the inhabitants. A greenery-covered projection on the southern facade offers residents the opportunity to individually extend their apartments in the shape of winter gardens at a time of their chosing. The additional floors are conceived to contain apartments in which the living rooms face southwards and the bedrooms are oriented towards the north.

The third strategy emphasizes the improvement of the floor plans and interior layout of the apartments. The second element of this strategy is a general enhancement of living comfort by adding a glass facade to the southeast. To this end, the existing southeastern facade is to be dismantled, the entire building structure extended, and an insulated aluminium-glass-facade mounted. Additional measures to improve energy-efficiency, proposed for all three buildings assessed in the pilot project, include heat insulation of the building shell, new, airtight windows, fixed and mobile shading elements, controlled ventilation with heat recovery from exhaust air, perforated plate collectors, collectors for hot water generation, ground collectors, and the improvement of the existing electro-mechanical facilities.