Material testing is essential to designing durable – and visually engaging – enclosures for energy infrastructure, meeting the long-term needs of utility plant and campus.
The Ohio East Regional Chiller Plant sits on a prominent site between campus and city, framing the main gateway for a new campus entry. With such a key urban role, the project had to fit comfortably among its smaller academic neighbors while distinguishing itself as a modern and critical infrastructure facility. Materiality, in combination with a dynamic building form, was key. The large scale of the structure is modulated by its composition of two offset volumes: a lower, glazed rectangular volume with semi-transparent views from the interior looking out, and an upper lifted square volume with perforated metal walls. The perforated copper-colored coated aluminum wrapper mimics the surrounding brick context while providing a contemporary twist. It also serves as a cost-effective water cooling tower enclosure.
Copper vs Anodized Aluminum vs Kynar on Aluminum
The LWA design team questioned what the best finish is to use for the copper-colored metal sheet screen. Because strong chemicals are used annually to clean the basis of the cooling towers on the roof, we tested several materials to see the long-term results of chemical splashing on the screen material. For the experiment we used:
1) 12 gauge Copper
2) 1/8” Anodized Aluminum with Linetec Copper Anodize (ANO-630AE)
3) 1/8” Aluminum with Linetec Kynar Finish, Classic Copper (LT727) 70% Kynar, AAMA Specification 2605
The experiment consisted of working with an independent testing agency to run multiple exposure cycles to test the impact of the cooling tower plume and the cooling tower basin cleaning chemicals on the several proposed screen materials: 100% copper, anodized aluminum panel and Kynar finish aluminum panel. Results were as follows: copper resulted in blotchy spots; anodized aluminum had a slight milky film formed; Kynar finish on aluminum remained unchanged. Consequently, we selected copper-colored Kynar finish on aluminum.
Perforation & Patterns
While finalizing the material choice, the design team simultaneously worked on an animated screen pattern that combined function and playful design. Since the screens were wrapping cooling towers, they had to achieve a 50% open area for ventilation, required for the equipment. This posed an inherent conflict between open are and screening as a perforation at more than 48% open area produced a screen that was too transparent to define the volume. After a rigorous study of options, the team selected screen walls that are designed with two perforated densities:
a) Panel 1: 1” Round Hole x 1.375” Staggered Center, ~48% open area and
b) Panel 2: 1/2” Round Hole x 1.375” Staggered Center, ~58% open area
Together with narrow open slots in between the panels that serve as vertical accents, the composition met the 50% open area while creating an engaging play between different densities. The narrow slots at 100% openness produce vertical accents in combination with the two different perforated panels.
Result
The final screen wrapper serves as an interpretation of the brick used prolifically on the university campus. The copper-colored perforated aluminum wrapper adds aesthetic variety to the surroundings while fulfilling the purely engineering needs of the infrastructure project. The building glitters both day and night and engages the community, displaying the technology inside.
Please note: During construction after bidding and selection of the cooling tower manufacturer, the selected manufacture determined that only 35% open air was required for its specific equipment. This allowed denser screening to be used with the same sized two perforation types but with a larger spacing between the perforations.
