Damesalen, University of Copenhagen
Text: Mikkelsen Arkitekter A/S
DAMESALEN, Copenhagen University.
The Damesal project is a result of the need to extend an existing university gymnastic hall with a testing laboratory. The necessary extra m2 were provided by adding a new building on top. The project offered an opportunity to explore an architectural concept where the geometry of the additional floor is designed in a simple and elegant box shape in glass. The architectural and functional variation happens as the glass façade responds to the program and functions within the building – A design, which is also informed by the surroundings and the climatic exposure. The building envelope embodies design and performance in the form of a novel, integrated concept, developed in collaboration between the Architect and the supplier of the customized glass solution. With increasing regulatory request for higher performing envelope solutions, there is a tendency going towards more insulation, thicker facades and reduced glass areas. In many cases with reduced architectural quality and less interaction between inside and outside as a result. Thin and high performing insulation within double and triple glazed units is an interesting response to “fat” facades. With the opportunity to study and freely play with façade layouts within large units, the design exercise can be broken down, and in greater detail reflect the need for daylight, views in and out, protection against solar exposure, and the need for insulation – still within one design.
Coming from double skin facade solutions with an architectural language composed from the design of different components in different planes within the depth of maybe 1 meter –it’s a challenge to imagine that architectural communication should happen within only 78 mm - the depth of the triple glazed unit. But the architectural quality of very thin facades is interesting – Imagining a façade design driven by a 2D graphic-like experience rather than depth and layering – it can create a 2D language of elegance trough use of visual filters, coatings or just thin insulation or other filtering components in the cavity of the glazed units. Imagine change of material happening in a hairline rather than around a mullion. We are not quitting here, but it’s really interesting and worth exploring further. Our work with Dow Corning has developed a strategy that on one hand deals with the local energy frame -and at the same time take orientation and solar exposure into account. Their calculations have, in dialogue, influenced the plan layout and level of glazed areas for specific orientations.
We have jointly and with assistance from Okalux studied different facade arrangements with the aim of developing a design that could meet different requirements for different orientations, reflecting different programs behind the facade, still within one architectural language.
Only by setting up parameters for design and constantly calculating different suggestions from the design team it was possible to get a feeling of what parameters would be driving the facade layout. Both horizontal and vertical layouts were tested, as well as solutions integrating Okalux components that redirect daylight and create a level of shading.
A façade must make sense and have noticeable quality from a distance of m2 as well as close up. The challenge is to communicate scale and materiality. We see things on a distance and expect more as we get closer. Equally important is the understanding of the facade experience inside the building in relation to the external experience. We often see facades that have none, or very little in common with the other side. By positioning an insulating material in the cavity of the triple lazed units there is an opportunity to experience the same material inside and outside, or have deliberate difference. For the Damesal project we are working with the same type of metal mesh surface to both sides, giving a homogenous understanding.
Only by studying samples and making mockups decisions could be taken.
INNOVATIVE CONCEPTUAL DESIGN AND COLLABORATIVE FEASIBILITY STUDY
In the construction sector, Dow Corning is well-known for high performance solutions for insulating glazing units and structural glazing based on silicone and silicon science. The collaborative innovation capabilities have been strengthened through deployment of in-house façade engineers who operate in the field between product development, application engineering and technical support on specific jobs. The dialogue between these specialists and the designers – in this case Mikkelsen Architects – yields opportunities for development of custom solutions on the basis of tried and tested applications. Such collaborations in turn inform the innovation work and product development activities, paving the way for future cutting edge solutions on the basis of real life development needs.
The collaboration of the glazing concept for the Damesal project comprised the following steps:
- Definition of the façade functionality based on building program and façade orientation;
- Determination of the energy frame (requirement set out in the building regulations);
- Studies of glazing build-ups, responding to design and performance requirements;
- Detailed analysis of energy performance of the different façade elements,
- Building energy performance assessment (code compliance check) and feedback for each of the elevations regarding the allowable ratio of opaque to non-opaque area,
- Physical visual mock-ups of glazing build-up options and specific details;
- Budget pricing based on preferred and alternative finishes and performance requirements;
- Design team buy-in sessions, agreeing on energy assessment methodology and compliance strategy;
- Performance specification based on detailed understanding of overall façade energy characteristics.
The definition of the façade functionality and thoughts on the desired architectural language has been discussed above. The overriding theme is that the collaborative effort was paramount in terms of defining with precision the desired design while continually checking technical feasibility, including compliance with the energy performance requirements stipulated by the building regulations. The close collaboration also facilitated budget costing as an integral part of concept development, ultimately offering to the designer (and the Client) reassurance that the proposed solutions were feasible from a cost perspective. In the following, the remaining steps are described briefly one by one.
DETERMINATION OF THE ENERGY FRAME
The Danish building regulations set out the energy performance requirements in terms of a so-called energy frame; code compliance is checked by means of a building energy performance model. A detailed description of the performance assessment method and the model is beyond the scope of this paper, but it is worth mentioning that traditionally a façade is split into conventional walls and windows.
By contrast, the Damesal façade is a curtain wall and – as such – behaves as a window with aluminum frames where parts of the window are opaque. Careful definition of the building envelope and its various parts is possible and this is an important aspect to clarify and agree on early in the design development. Dow Corning clarified the requirements with the mechanical engineer (responsible for the environmental strategy and code compliance checks), and agreed on an appropriate approach to modeling the new building.
STUDIES OF THE GLAZING BUILD-UPS DETAILED GLAZING ENERGY PERFORMANCE ANALYSIS
The different glazing build-ups were modeled and their thermal transmission determined, taking carefully into account the effect of the edge details (spacer profiles) and frames. The analysis was based on generic high performance frames, glass with high performance coatings, and argon-filled insulating glazing units. Once the different elements of the façade were characterized, the overall façade performance was assessed by calculation of area-weighted thermaltransmission coefficients (U-values). A simplified model was used for the solar transmission properties of the translucent and vision areas of the glazing.