April 26, 2018
The following is the first in a Better Know a Building series, which aims to share information about buildings Cycloners admire for their innovative engineering, architecture, and general design.
A few years ago, my husband and I road tripped through Utah’s national parks, and when we got to Zion, we rolled up just in time to snag one of the last campsites at the South Campground. While I didn’t like how our tent almost blew away every night or how the sun shined directly on my face every morning, I did like how close the site was to the visitor center.
It’s true that I love most national park visitor centers anyway because they have tiny topographical dioramas of the whole parks, but Zion’s seemed extra special. It was comfortably lit, even though I didn’t see any lights on; the temperature inside was pleasant, despite how early it heated up outside; and the building seemed like it fit so naturally into the landscape.
Flash forward to a few weeks ago. Every Monday, Cyclone’s analysts get together for a Knowledge Forum lunch to talk about project-related questions and observations and to present any other information we think might be interesting for the group. Our company head, Benny, has dubbed this group the Energy Lab, which he describes as “a group of super talented people with creative ideas talking to each other and sharing knowledge.”
At this particular Knowledge Forum, my colleague Irina presented on passive building design strategies, and lo and behold, there was Zion Visitor Center in her slide deck. Her presentation got us talking about examples of passive design in buildings we’ve visited, and there ended up being a lot. Apparently we not only like working on innovative buildings, we like visiting them too. I thought it might be fun to share some of the buildings we talked about on the blog as well, and where better to start than the architectural star of southwest Utah itself, the Zion National Park Visitor Center.
If you like reading conference papers, you can find a great one about the entire design process by NREL here. If you’re more of a CliffsNotes-style conference paper person, read on.
In the late 1990s, the National Park Service and the National Renewable Energy Lab (NREL) began a collaborative, whole-building design process for the Zion National Park Visitor Center. Architects, engineers, and energy consultants worked together on the building throughout the entire project. Typically, the architecture of a building is submitted first, and then mechanical systems are developed to accommodate the building’s designed form. Designing the architectural and mechanical elements of the building in tandem, however, allowed for more elegant solutions with systems that complement each other and use less energy.
Here are just a few of the Zion Visitor Center’s notable features:
- Operable Clerestory Windows
- Clerestories are rows of windows located above eye level, and you’re likely to find them in a lot of buildings that have been designed with sustainability in mind. Their use at the Zion Visitor Center are a big part of why I felt so comfortable inside: they let in lots of soft, ambient, natural light.
- The visitor center’s clerestory windows are operable as well, which allows for improved airflow and circulation and the ability to use natural ventilation as a first step in cooling the building.
- Down-Draft Cooltowers for evaporative cooling without distribution fans
- Cooltowers work by circulating water through evaporative pads at the top of a tower. Dry outside air that moves across the pads naturally sinks and cools occupied spaces.
- One of my favorite description from NREL’s conference paper about the building was about how they decided to use cooltowers. “Tall, wet canyon walls and hanging gardens cause a natural cooling effect in the canyon. The cooled air then drops out of the slot canyon into the wider canyon at its base. Architects incorporated similar tall elements in their design to give the building perspective within the canyon environment.”
- Trombe walls and direct solar gains for heating
- Trombe walls, named after French inventor Felix Trombe in the 1950s, are a passive thermal storage systems. They consist of a thick masonry wall that’s placed just inside of a layer of single- or double-pane glass, with an air gap of a few inches between the two. The surface of the masonry wall that faces the glass is typically painted a dark color. To maximize their functionality, trombe walls are built on southern facades of buildings, so they can collect heat from sunlight that passes through the layer of glass throughout the day. Heat that’s stored in the masonry wall is then released into the occupied space of a building after the sun sets. It’s a little bit like keeping a pizza stone in your oven all the time for more even temperature control. Thermal mass is everywhere!
- The visitor center also uses a clever passive heating strategy with its clerestory windows. The lower solar angle during winter months allows light to enter the occupied space directly, helping to heat it up. An overhang above the clerestory windows keeps direct sun out during summer months when the solar angle is higher.
The visitor center also uses solar voltaic panels to offset its electricity use, daylighting controls, highly insulated walls, and outdoor shade structures, among many other passive, efficient, and environmentally friendly features. It’s definitely worth a visit, and by all means if you find yourself there, consider exploring the majesty of the actual Zion National Park too.
If you’d like to know more about passive design strategies and how they can make your building better, contact us at email@example.com.