Pahranagat’s Zero Net Energy promise: where are we now?

By: Jordan Miller
19 June 2018

In celebration of its recent LEED Gold certification, it’s high time to revisit Parhanagat National Wildlife Refuge Visitor Contact Center in Pahranagat Valley, NV. Pahranagat represents the pinnacle of CTA’s initiative of sustainability, harnessing the valley’s natural elements, incorporating select green technologies, and making full use of CTA’s core principle of integrated design. With a Zero Net Energy (ZNE) goal, designers aimed to balance the building’s energy consumption with its energy output, and perhaps even push more energy back onto the electrical grid than it draws. Sustainability, it should be said, was held in the same regard as the rich cultural history and context of the valley: designers drew inspiration from the landscape, forms, and local native wildlife and traditions.

YEAR ONE

In its first year — July 2014 to June 2015 — Pahranagat met its goal with flying colors. In fact, the building produced nearly twice as much energy as it exhausted over the course of the 12-month period, as represented in the graphs below.

While this was extremely promising for the building’s energy projections, it was merely that: a projection. After all, the building was unoccupied for a portion of the year, and the sustainable functioning of energy systems and equipment over an extended period would indicate much more compelling and significant results.

Today, nearly four years from the 2014 completion of the project, additional data shed light on the complete picture of Pahranagat’s sustainability.

WHERE ARE WE NOW?

Pahranagat Energy Usage 3-28-18 Update -2
Pahranagat Energy Usage 3-28-18 Update -4
Pahranagat Energy Usage 3-28-18 Update

In its latest year the building outperformed the impressive precedent it had set in its first twelve months of operation. Even as it saw heavier use, increased energy demands were met by far superior photovoltaic generation, which ultimately pushed more energy back onto the electrical grid than it drew. Specifically, the building generated 1.64 times what it consumed. In other words, it put 1.64 units of energy back on the grid for every 1 it consumed, on average.

Even in December 2017, which was projected to be the month in which the most energy was consumed, Pahranagat had a negative net energy consumption and was ultimately a generative force for the electrical grid. Only in one month of the past year — January 2018 — did the building draw more energy than it consumed. This is to be expected in the dead of winter, when daylight is at a minimum and heat demands are high, and is radically offset by the energy generated throughout the rest of the year.

Pahranagat’s energy systems are anticipated to function at this level for the next 20 years, ensuring the building’s sustainability is, in a manner of speaking, sustainable.

DESIGN ESSENTIALS

Though designers aimed to achieve top-of-the-line sustainability, they were unwavering in their embrace of simplicity. Rather than piling on new and expensive technologies in a Rube Goldberg fashion, they turned to the surrounding Pahranagat Valley for inspiration.

The first step of any sustainable project is to consider form and orientation. Designers honored the local native tradition of east-facing entrances and views toward the westward water feature. Overhangs were incorporated in the design to shade incoming pedestrians as they enter the building and shade the windows to protect the interior from direct sunlight. Glass — which tends to read as modern and sleek but is in reality wildly inefficient in energy conservation — was avoided in favor of wood stud-framing, COR-TEN steel panels, stucco, aluminum/fiberglass windows, and standing seam metal roofing. In addition to blending into the textures and landscape of the surrounding desert, these materials proved to be great candidates for efficient construction in such a remote location.

The guiding idea for Pahranagat’s energy systems was to consider the building a lung, breathing the surrounding environment. As daylight is harvested by the roof-mounted photovoltaic solar panels, a horizontal ground loop heat pump system circulates water to regulate the building’s temperature. These systems ensure the building’s presence is as seamless as possible with the surrounding area, and entail only simple, intuitive maintenance comparable to a typical residential unit.

INTEGRATED DESIGN

The successful execution of these ambitions is largely a function of integrated design. The MacLeamy curve, which visualizes the impact and cost of design decisions at different points in the design process, demonstrates the value in incorporating the voice of energy experts and designers as early as possible. In this way, the energy data from Pahranagat is not only encouraging in the conversation of sustainable design, but verifies the value of an integrated design process, and thereby an integrated firm. 

The Pahranagat Wildlife Refuge, in addition to being LEED Gold certified, was granted an AIA Honor Award from the AIA Idaho 2016 Design Awards and deemed an official zero energy building by the New Buildings Institute, is a standout in CTA’s legacy of sustainability and integrated design. It sets a high precedent in value engineering and seamless environmental design, and stands as an important example of sustainable design and a bold step toward the AIA 2030 Commitment.

Visit our sustainability page to learn more about our commitment to sustainable design.

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