Bistable Facade

Dundee School of Architecture, University of Dundee, Dundee, Scotland

Project idea

The University of Dundee’s Crawford Building is home to numerous arts
programs Such As Fine Arts, Animation, Jewelery Design, Graphic Design, and Textile Design. The Original structure was originally constructed In 1953 (using Designs from 20 years prior) and then extended numerous times. Needless to Say the building is outdated and in need of renovation. The proposal aims to Keep as much of the original structure as possible while also improving the Thermal envelope, environemntal impact, and enjoyment of the space.

Project description

The interior is split into 6 sections; painting, animation, textile, ceramics, and jewelery galleries, as well as a studio space. The primary objective was to segregate the gallery spaces from the studio space as, while gallery spaces are quiet and clean, studio spaces are loud messy. The next step was to address the interior flow by creating a dynamic, yet accessible and space conscious set of spaces. The design needed to be repeatable, yet functional in a vacuum, so space was limited. Using a stair seating setup with a hollow interior allows for storage space underneath, while sliding doors give student, faculty, and observers the opportunity to open and close the spaces to their liking.

The first aim of rethinking the Crawford facade was to harnass the power of
the sun to create energy. The sun generates 3.8 x 10^26 watts of power per
SECOND and we are not utilising this natural source of energy to its full
potential, or even close to it... The Crawford building employs the stack effect
to make use of the suns rays, as well as solar panels to power the water
heating system.

Double skin facades/solar chimneys generally leave little room for ornamentation and when something fancy is put on, it is on the exterior of the facade. This however, completely defeats the purpose of the double skin facade, being that when it is covered up, it cannot bring in any heat from the sun. Putting the ornamentation on the interior is also flawed as while it allows the radiant heat to enter the facade, it still allows it to infiltrate the the interior. On hot days this is not ideal and prevents maximum efficiency by letting in excess heat. Furthermore, a windows effectiveness in letting in heat outweighs the leaking of heat via the window (25% vs 10%).

That is why the facade is best placed between the two glazing layers. Again, this leaves little to play with as the ideal distance between the two layers of glazing for utilising the stack effect is 900mm, and minimising the amount of space taken up by the facade within that envelope will maximise its efficiency in holding heat and ventilating that heat upwards to escape and and enter the heat recovery system.

The bistable facade aims to take up as little space as possible within the
double skin facade, while still providing a dynamic and visually pleasing
tesselative pattern. The fabric/paper aspect reinforces the activities that
go on inside the building; that being an art college.

The facade is heavily inspired by slap Bracelts of all things. When trying to come up with ways to create two states within the facade. Slap bracelets’ material is known to be ‘bi-stable’, meaning it is stable in two different states. The slap bracelet is stable in its straight form, as well as its wrist bending form.

Using bistability on its lonesome would be an excellent way to keep building users engaged with the function of the facade, however, the kinetic aspect is between the two sets of glazing, thus inaccessable unless users open the windows. Therefor there needs to be an automated aspect to change the facade into its two states without being physically touched. This is done with stepper motors that can easily be controlled ‘per window’ within the within the Crawford building. The facade can then bloom like a Lotus Flower, then retract within an instant.

Technical information

1. Single pane glass
Single paned glass outer facade easily lets light into the solar chimney.
2. Spider fixing system (Fig. 6)
In place to hold together both the exterior glazing, and facade elements.
3. Grilled boardwalk (Fig. 3)
Grilled boardwalk gives easy access to the double skin facade for cleaning and maintenece purposes.
4. Kinetic facade panels
Kinetic facade lets in light when the sun is at an indirect angle or is an overcast day, but diffuses it when it is looking to directly infiltrate the spaces. Refer to the second sheet for more information.
5. Kinetic facade frame
Fixed to the spider fixing system.
6. Adjustable vents (fig. 2)
Vents automatically open and close depending on the cycle conditions of the current weather. Refer to the environmental sections for a general functionality assessment.
7. Double glazed low-e glass adjustable windows (Fig. 5/7)
They are filled with argon gas creates a better insulation barrier and the windows are adjustable and fold into the space, allowing for easy cleaning, maintenence, and additional ventilation of the space.
8. Black load-bearing wall
Reinforced concrete wall helps bring solar radiation into the double skin facade, provide load-bearing support for the roof and curtain wall, and hide
the rooftop heat exchanger that is positioned right behind it.
9. North-facing adjustable windows
Windows along the north faces go hand in hand with the adjustable vents on the north facade to cross-ventilate the space, especially when the wind is coming from the south.
10. Boiler
Provides heated water for the floor heating system. Is placed on the roof as it can utilise gravity to circumvent the water throughout the buildings, cutting down on energy consumption.
11. Photovoltaic cells
Solar panel system along the northernmost roof provide enough energy (ideally) to power the underfloor heating system and heat recovery system. This ensures the building is at most, only partially reliant on fossil fuels for heating.
12. Heat Recovery System (Fig. 1)
Is connected to the solar chimney double-facade. Once the hot air reaches the top of the facade, it is pushed into a heat exchanger which heats incoming fresh air from outdoors and equally distributed throughout the building. As a result, the musty air will be cooled and sent outdoors.
13. Underfloor heating system (Fig. 8)
Underfloor heating system (fig. 2) offsets the lower floors’ cooler temperatures when cross-ventilating the space. This system is used instead of radiators because it keeps dust at bay and allows heat to rise from underneath. There is insulation beneath the heating system to push the heat upwards to further justify this.
14. Sliding doors
Sliding doors give users the option to close the spaces as well as open the Spaces for larger or combined showcases.
15. Bleacher stairs (Fig. 4)
Stairs bridging the ground floor to the first floor contain seating to view Animation projects and exhibitions put on by the students and staff. They Help mitigate the tight parameters set for the project by being multi-functional.
16. Open ceiling
Vents and mechanics are visibly present in the studio to promote a ‘working’ environment
17. Closed ceiling
Ceilings in the gallery spaces are closed to keep them clean, refraining from competing with the visual higharchy of the art. The ceiling utilises Heartfelts. Linear Textile ceiling system, angled towards the north and south facades of the space, drawing people into the gallery spaces. They also will dampen any sound, which along with the lack of voids in the studio space, prevents any unwanted noise entering the gallery spaces from obnoxious students.