Exhibition Eco: An unpretentious prototype production building in a demonstration ecology park involves ingenious technological and sustainable devices for conserving energy.

The Ecopark on the edge of the small town of Hartberg in Styria was set up as a demonstration of ecological design and construction. Built on the site of a former clay pit, it was intended to be self-sufficient, and to heal the bruising of the land without depositing debris elsewhere. The buildings -- exhibition and production sites as in a normal industrial estate -- were to be as unpolluting and sparing of energy as possible, in terms of both consumed and embodied energy. At the north-east end, there is a natural pond to absorb run-off water while attracting and nurturing wildlife. On an adjacent site Konrad Frey, a pioneer in solar architecture in Austria since the 1970s, was commissioned by the park's organizers for a prototype production building. Its task was to act first as an exhibition pavilion and then as a factory/warehouse for solar equipment. Sited at the north end, it lies to the west of the ecological pond with a high protective bank dividing it from the highway behind. It is approached via a d rive from the south which terminates in its car park.

Frey accepted from the start that the main task was to provide economical general purpose spaces, and he made two 700[m.sup.2] linear building tracts 16m wide and 7m high which can be used separately or together. They have contrasting characters according to position: the northern one with a fully glazed end enjoying a dramatic view of the pond while the southern has continuous low glazing towards the approach. A second brief requirement asked for offices, changing and recreation rooms which have been built within the east end of the southern tract as a two-storey block. Above them on the roof is the curved conference room with its external terrace and longer views, the one touch of real extravagance in an otherwise low-cost project, and full of interesting details. Various sun-shading devices are applied to the different faces of the buildings in response to the calculated exposure. The south facade, for example, has Frey-designed stretched fabric screens over the windows, but it also serves as a testing gro und for a demonstration of solar collectors and solar control devices. Since these products change, it retains a deliberately experimental and provisional look.

At first sight this project might seem banal with its boxy forms and standardized elements, for it accepts the realities of industrial estates and of serial production, but the closer you look the more unusual it seems. The energy-rich steel frame expected in such buildings is completely lacking. Instead the simple foundations support minimal concrete columns at 5m intervals, and these do not reach the roof. Instead they support timber-framed facade panels skinned in particle board, which form a continuous edge to bear the roof. Frey reveals this structural system on the north side where it breaks for windows, for he shows T-shaped glazing with visible trusses in place of the missing panels. The all-timber roof deck spanning the 16m building width follows the stressed-skin principle. Plywood box sections 600mm deep containing their own thick insulation layer were prefabricated then hoisted into place, resting on the side panels. The slightly sloping roof surfaces, topped with a membrane and a thin soil layer to encourage plants, meet at a central gutter. Lining the ceiling is a layer of wood-wool which acts as acoustic absorbent. Unbroken by the usual beams, its surface allows heating and artificial lighting elements to be freely placed. To show the free-spanning nature of the roof structure at its open end, the glazed east wall -- set back a bay for solar protection -- has only the minimal steel supports required for wind load. The insulated double glazing is divided in three horizontal layers, and since the vertical glazing joints were not structural and only limited by delivery sizes, Frey could play with the rhythm, taking his cue from the thematically appropriate '50s hit song 'O sole mio'.

Another structural curiosity is the support for the conference room on the roof. This penthouse element would have caused too much deflection in the stressed skin structure, so it is suspended from exposed trusses above, which transmit its loads back to the columns. The structural network so provided also turned into a convenient bearer for a stretched canvas awning for the terrace. Conventionally skinned in metal, the penthouse roof drains to a gutter on the north side.

The long side walls are clad in timber slats, which give mechanical protection to the insulation layer beneath while allowing it to breathe. For the end walls, Frey used PVC sheet, a controversial material in ecological terms, but used in relatively small quantity. Interestingly, this is the one element that the client has asked Frey to change because it sends the wrong signals about the park's ecological aims. It is being replaced by a more cosy-looking and predictable fur coat of coconut netting.

In the age of image and spin, the look is often more important than the reality, and in ecological matters people want to placate their consciences while continuing with their recklessly consumptive lifestyles. So it is difficult to see, in the often chaotic display of ecological projects, just what will really count and what is mere window dressing. The solar collectors on the front of Frey's building, for example, have become an obvious symbol of ecological concern, almost a cliche. But the various sun-shading devices and the setback of the large east window are both more cheaply achieved and passively effective. These are the kinds of measures architects should surely now be adopting as a matter of course. Potentially Frey's most important innovation, though, is the timber-based wide-span roof structure. If this were applied to every such shed in every industrial and commercial estate in Europe, an enormous energy saving would be effected.

REALTED ARTICLE: Architect

Konrad Frey, Graz

Photographs

Angelo Kaunat

1 Building is in two linear tracts which can be used separately or together.

2 South elevation: conference room on roof is hung from exposed trusses. Fabric shades protect from overheating.

3 Glazed east wall is shaded by being recessed one bay. Building celebrates its economical and industrial origins.

4, 5 Simple mass-produced components are used to reduce embodied energy.

6,7 Conference room on roof supported by exposed trusses over terrace that also carry shading fabrics.