human scale kinetic skin

interlocking louver shading systemwithin double skin façade envelope

Josh Kuffner

University of CincinnatiARCH 713 Elective Studio

Parametric DesignProfessor Ming Tang

concepts

The primary concept inherent to all iterations of this project is as follows: each involves a pivoting shading device, within the envelope of a double skinned façade, with at least three positions and thereby three different levels of shading available in order to best temper the incident solar light and heat entering the building. The double skinned curtain wall is in response to Chicago’s marked temperature swings, with frigid winters and hot, humid summers. It will provide a thermal buffer and reduce the overall building heating and cooling costs. The kinetic elements of the building façade, being within the enclosure of the double skin, are protected from the area’s inclement weather. These elements are designed to best handle varying solar exposure throughout the time lapse of a single day, as opposed to a generalized annual solution. The massive east and west exposures of this building require some shading solution given this less-than-ideal site orientation.

The preliminary concept, Scheme I, is a rotating system of shutters, in which each pivot holds two shutter panels comprised of individual louvers. These are so arranged so that when open, the shutters interlock with each other due to the staggered placement of louvers and provide for clear views out. As less sun exposure is desired by the user or, alternatively, is sensed by lighting sensors, one of the two shutters closes, providing some shade to the interior environment. If more shading is needed, the other shutter closes, interlocking with the next shutter over.

The second scheme is a variant of Scheme I, with an added level of complexity. While Scheme I used louvers that were the same size throughout each shutter, Scheme II provides louvers with circular cross-sections that diminish in diameter as they approach the height of a seated or standing person, which allows for easier views to the outdoors. In order to still provide adequate shading, the smaller diameter louvers are more densely distributed, while the larger louvers are less densely distributed.

perspective

open0% opacity

half30% opacity

closed60% opacity

scheme I

plan

elevation

scheme II

elevationhuman scale controls louver density

perspective

precedents

This overall concept drew precedent from several buildings, notably, the GSW Headquarters building by Sauerbruch Hutton Architects in Berlin and the Q1 building by JSWD Architeketen in Essen, Germany.

The GSW Headquarters was chosen as a precedent, because of its usage of a double skin with an operable shading element within. The building’s orientation, longitudinally north-south, is also a trait shared by the Cold Storage building, and so a similar shading system is a logical solution. Within each panel of the curtain wall of the GSW HQ are three operable fins that can open, close, or slide out of the way for unimpeded views. The panels are perforated to allow for views while the panels are in the closed position. The double skin acts as a thermal flue that carries hot air up and out of the building.

The Q1 building in Essen was selected as a precedent after the idea of interlocking louvers was decided upon. While the louvers do not interlock with the next shutter over as in the façade proposed for the cold storage building, they interlock while in the open position. The kinetic façade elements in this case are not contained within a double skin, but rather on an external framework.

gsw headquarters q1 building

design development

After the 3 conceptual phases of the project were completed, Scheme II was selected for further advancement. The first modification made was to change the cross-section of the individual louvers from circular to rectangular, in order to better shade the building interior, and to more visibly denote the governing human scale parameter.

This parameter, related to the height of a human in the seated/standing range, is translated to the rectangular geometry by the same grasshopper script as the one used for Scheme II, with some modifications. The rectangles become larger in scale and less dense as they deviate away from this height range.

position 1:left side open

right side open

position 2:left side open

right side closed

position 3:left side closed

right side closed

design development

In addition to the louver cross-section being altered to rectangular, a rotation is applied to the louver in some instances. This rotation is mostly to deflect glare from incident solar rays and diffuse refracted light from the sky away from the building.

In addition, four distinct shutter systems were created, one for each of the buildings four main exposures. The differences between each model are inherent to the sun angles when affecting that particular exposure.

On the south side of the building, some of the upper louvers are not rotated, and this allows the sunlight to reflect off the louvers top surface and rebound off the ceiling inside the building, acting as a light shelf. The lower louvers on the south model do not perform in this way, as to not cause glare that might bother building users.

The northern exposure, rarely having any incident solar radiation, utilizes the louver system to maintain consistency of the skin across the facades, and also to mediate diffuse glare from the sky. The need for a room to be shaded for certain functions can also still be accomplished.

The eastern and western exposures of the building, while receiving similar low sun angles, are slightly different. The western exposure is considerably denser than its eastern variant, taking into account the higher level of solar heat gain during the afternoon.

north:

- 35 angled louvers per shutter- louvers deflect indirect sky glare

south:

- 60 louvers per shutter- lower 38 louvers are angled to counter glare- upper 22 louvers are flat to reflect incident light onto ceiling

east:

- 45 angled louvers per shutter- louvers deflect early morning sun when closed

west:

- 60 angled louvers per shutter- louvers deflect late afternoon sun when closed

initial fabrication

The fabrication of an operating version of the pivoting and interlocking shutter system would be a technically sophisticated process. In order to best visualise the movements of the shutters without this complexity, a simplified physical model is being produced.

This model consists of two hinge pieces and louvers laser cut from chipboard. The louvers do not vary in thickness or tilt as they do in the computer model. Regardless, when completed, this model will allow for ease of understanding regarding the facade’s movement while more complex models are being formulated.

fabrication photos

grasshopper script

Several elements of the louver system are controlled by parameters driven by the Rhino plug-in Grasshopper. This is the script for a single folding element of the the south façade.

1. This slider controls the number of louvers per shutter.2. This graph, set to a particular bezier spline, dictates

the vertical placement of the louvers, with more density around the scale of human height.

3. This slider controls the height of the shutters.4. This series is made up of only even numbers, while

the corresponding series for the other shutter on the same pivot is only odd. This ensures that the shutters can interlock smoothly and without colliding at any point.

5. This slider controls the length of the louvers/shutters.6. This line, at 48” above the finished floor heght, is the

parameter that represents the height of a seated human.

7. This slider controls the louver cross-sectional scale.8. This group relates the human height line to the louver

density.9. This slider controls louver depth.10. This element determines the louver cross-section.

Here it is a rectangle.11. This group is present only on the south facade shutter

script. It determines which louvers are rotated from the horizontal.

12. This slider controls the louver angle with respect to the horizontal, in radians.

13. This group extrudes a louver mass from the cross-sectional profile specified.

14. This pipe element draws the central pivot.

12

3

4

5 6 7

8

9

10

11

12

13

14

site

The building site has been modified considerably from the original cold storage facility layout. The western low-rise buildings and elevator tower have been removed, with the site being developed with a 5-storey, 40,000 square foot addition on the northern half of the site and a public plaza on the southern half.

The site redevelopment, like the design of the individual facade elements, caters to the human scale. The addition steps back in setbacks, as to not overwhelm pedestrians with a sheer facade. The sheer facade of the original structure is somewhat mediated by setting the lower retail units back from the office floors above. The plaza consists of several elevated plantings with ample opportunity for human interaction. The troublesome 3’-6” discrepancy between the floor of the main building and sidewalk level is reconciled with sloped pavement surfaces and ramps.

site plansite axonometric

retail 1 retail 2 retail 3

office lobby

retail 4

retail 5

retail 6 retail 7 publicplaza

parking deck entrance

scale: NTS

loading docks

building elevations

north

south

east

west

double skin detail section

1. 23”x23” concrete column with capital

2. exterior insulating double glazing

3. interior double glazing

4. aluminum mullion

5. south façade ceramic louvers

6. south façade louver pivot

7. rotator motor

8. silicone joint seal

9. steel grid catwalk

10. steel outrigger beam

11. 9” concrete floor slab

1

2

5

3

4

6

7

9

10

11

8

scale: NTS

exterior perspective

interior perspective shutters in position 1

interior perspective shutters in position 2

interior perspective shutters in position 3

human scale kinetic skin

concepts development / fabrication renders