Getting To Zero: 2017 ASHRAE LowDown Showdown Teams Propose Energy, Costs Savings
From eSociety, October 2017
By Mary Kate McGowan, Associate Editor, News
ATLANTA—Tasked with retrofitting a building in the Washington, D.C., area and armed with unreliable design and measurement information, four teams were challenged to transform it into a net zero energy building in this year’s ASHRAE LowDown Showdown Competition.
“Spoiler, we didn’t quite get (to net zero energy),” said James Cullin, Associate Member ASHRAE, who was part of the first place team, the Sustainability Savants.
None of the four teams reached the net zero energy goal, but all reduced the building’s energy use by at least 69%.
The teams presented their solutions last week during the 2017 ASHRAE Building Performance Analysis Conference in Atlanta.
They were challenged to reduce energy use in a building that is a combination of storage facilities for books and papers and an office.
The storage facility must be kept at 60°F (16°C) and 40% relative humidity year-round to protect the paper being stored. One of the three storage facilities has rooftop units air conditioning, and the other two have air-handling units with cold water coils and desiccant wheels.
The office facilities have no humidity requirements, have a variable air volume (VAV) reheat system and are occupied during the workday throughout the year. The storage facilities have no occupants except the people who move in and out collecting books and putting away deliveries.
The 1980s-era building experiences D.C.’s hot and humid climate in the summer and its cold, dry climate in the winter.
Sustainability Savants
The first place team and the “fan favorite” competition winner, the Sustainability Savants’ strategy resulted in 83% energy savings, according to Cullin.
The Savants proposed renovating the storage facility’s building envelope by:
- Adding insulation on vertical walls;
- Installing fly roof shades to provide a solar PV platform; and
- Reducing infiltration by verifying building tightness and increasing operational awareness.
The team also planned to install “Follow Me” style occupancy controls where the lights only operate when someone is within a certain range. The team reduced the facilities’ lighting energy by about 75%, according to the presentation.
Cullin said his team’s unique approach was separating the ventilation and the space conditioning aspects. By doing so, the two individual systems were able to become more efficient as opposed to when they were operating as one system, he said.
The Savants’ four active members, who all work at different locations of PAE Consulting Engineers, took turns presenting pieces of their team’s plans, which the judges appreciated.
“We all four had our parts to play,” said Cullin. “The sharing the knowledge is the big thing. That’s why we’re here.”
Sandstorm Stoppers
The second place team, the Sandstorm Stoppers, hailed from throughout the world including Lebanon and Abu Dhabi, United Arab Emirates, according to team captain, Junaid Bin Naseer, Associate Member ASHRAE.
“We were all in different cities,” he said.
The Sandstorm Stoppers’ proposals resulted in about 87% energy savings, without using renewable energy, and savings totaled more than $200,000.
Naseer’s team proposed to reduce the window U-value, infiltration and the storage facilities’ heating setpoint. Other retrofits included converting all lighting to LED, packaging the outdoor heat pump with energy recovery wheel for the administrative offices and adding solar PVs to the building’s roof.
The team also presented options such as replacing the rooftop units with a package unit and desiccant wheel and replacing the centrifugal fans with direct-drive plenum fans.
The Sandstorm Stoppers’ presentation was filled with detailed data and analytics, which the judges said they appreciated during one of their discussions.
Nothin’ but Net Zero
Between sessions, the judges discussed different attributes of the teams’ presentations. They said they liked how the Nothin’ but Net Zero team made its design decisions with financial costs to the building owner in mind.
Nothin’ but Net Zero’s proposals were able to reduce the calibrated model’s energy use intensity from 216.5 kBtu/ft2 (2458.7 MJ/m2) to 65.6 kBtu/ft2 (745 MJ/m2)—just more than a 69 percent decrease in energy use— through energy conservation measures including demand-controlled ventilation, solar thermal energy, interior and exterior LED lighting and a gas boiler, according to the team’s presentation.
Nothin’ but Net Zero’s plan also included installing high-speed doors “Iike the ones in Star Trek” in the storage facilities, said team captain Christian Taber, Member ASHRAE.
“One of the notes indicated the doors were left open during the loading and unloading when materials were brought in and out of the facility. We assumed a large infiltration load due to those doors being open,” he said.
re+ro
The final team to present, re+ro, was the sole group who proposed eliminating the preheat coils in the storage area because the team’s calibrations proved them unnecessary.
“That was important to us, making sure we calibrated the models,” said re+ro team member Brian Turner, Member ASHRAE. “Figuring out what all those coils were doing and why they were doing it was part of what made our project good.”
It was the only team to use ASHRAE Guideline 14, Measurement of Energy, Demand, and Water Savings, in its calibration process.
The team’s other solutions include reducing infiltration in the office building and using a ground source heat pump to reduce infiltrations in the storage building.
re+ro’s work resulted in a 75% decrease in energy use and more than $270,000 in annual energy cost savings with a 8.6 year simple payback period.
Challenges and Lessons Learned
The inspiration for this year’s competition challenge was born from a real-life work project one of the judges, Annie Marston, Ph.D., Member ASHRAE, worked on.
At the end of the session’s question-and-answer portion, Marston revealed the answers behind some of the project’s challenge.
Regarding the preheat coils, Marston said that was one of the “gotchas” in the challenge and eliminating them was a solution her firm proposed to the actual business.
Her team discovered through using psychrometric charts that two of the coils were heating and cooling for no reason. They eliminated those coils and reduced the building’s energy use by more than 50%, saving the owner about $100,000, Marston told the audience and teams during the Q&A session.
“That took a good month of investigation and really figuring out what was going on,” she said.
Another challenge centered on the information the Showdown’s teams were given. Marston said the majority of that information was part of the construction design, and not what was actually installed in the building.
“That happens all the time, so you really have to go through the documentation to see what’s really going on,” she said.
After the presentations and the Q&A session, Cullin, from the Sustainability Savants, said not being able to see the building to determine the accurate numbers was different compared to his job.
“The big lesson here is that when you’re dealing with a retrofit, you can’t always trust the design documents to be 100% accurate. Ideally, you would have someone go walk the facility to confirm as-built conditions before you start doing any of this,” he said.
While the project was challenging and called for the competitors to work nights and weekends to complete the project, Turner, of re+ro, said his experience was good practice to enhance his retrofitting commissioning work as well as his experience working with people he did not previously know.
“You can always learn from someone else. Whether it’s a daylighting expert or an architect, just understanding how people use different tools, different work flows...is a good experience to broaden your horizons from what you do at your desk everyday,” Turner said.
The next ASHRAE LowDown Showdown Competition is set for the 2018 Building Performance Analysis Conference and SimBuild co-organized by ASHRAE and IBPSA-USA in Chicago next September.