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2018 ASHRAE LowDown Showdown Competition

As Low As You Can Go: 2018 ASHRAE LowDown Showdown Competition Aims for Zero

By Mary Kate McGowan, Associate Editor, News
From eSociety, October 2018

The mission of the 2018 ASHRAE LowDown Showdown modeling competition is simple: design and model a net zero or near net zero building. The process to achieve this goal is not so simple.

The 2018 competition was held in conjunction with the 2018 Building Performance Analysis Conference and SimBuild in September. Eight teams were tasked with adopting new techniques and workflows to advance modeling and simulation to meet the growing challenges faced by today’s designers and modelers.


The model building was a 60,000 ft2 (5574 m2) museum (new construction) located in Denver that included retail space and a full service restaurant. The teams were evaluated in six categories: energy use, teamwork, innovative approach, creativity, workflow and presentation.

The winning team, 43 | 40, innovated its energy modeling workflow and modeled the building to have a total energy use of 227 MWh and a site EUI of 0.00381 kWh/ft2 (0.041 kWh/m2).

The team of seven work for WalterFedy, and the team’s innovative workflow played into what they were trying to accomplish at work, said team captain Cory Rosa. Although all team members of 43 | 40 have the same employer, Rosa said they worked on the LowDown Showdown presentation after work for several months.

Rosa said the team focused on analyzing and developing better workflows for energy modeling throughout the competition. One of the major workflow changes was dynamic reporting, which Rosa explained as a way of embedding an analysis within a PDF report that can automatically update if an analysis changes.

“Any change to the analysis can propagate through the entire report,” he said.

While the team brainstormed several workflow ideas, Rosa said they were challenged with ideas that did not pan out. He said they have a long-term goal of creating an energy modeling workflow that allows those working on the project to specify their goals by energy modeling criteria as opposed to building designs.

The team’s winning design included strategies such as daylighting, natural ventilation and geothermal energy.

One of the competition judges, Dennis Knight, P.E., Fellow ASHRAE, said many of the teams gravitated to using ground source heat pumps as a solution, but every team came up with that solution independently. He said the building's climate lent itself to that solution. 

Susan Collins, a member of the 2018 LowDown Showdown Competition Committee, said the teams' creative uses of daylighting were also notable.

43 | 40's model building uses a ground source variable refrigerant flow (VRF) system that provides all heating and cooling and reduces thermal transport and air handling electricity consumption.

Because the building had a greater heating load than a cooling load, 43 | 40 considered using thermal energy from the sun to recharge the ground, Rosa said.

“Over time, the ground will become cold, and your system will become inefficient. So we used the sun to heat the ground back up and keep it up at a constant temperature,” he said.

Rosa said his team knew they wanted to embed part of the building underground to reduce its heating and cooling loads. With the extra green space created on top of the building, 43 | 40 wanted to house sheep. The building would use sheep wool as insulation, and the sheep that lived on top of the building would produce wool to replenish the insulation, he said.

Rosa credited the other teams for their innovative ideas, especially the second-place winners, Net Zero Heroes. Rosa said he was impressed by that team’s work to model passive ventilation.

Knight said the competition grants participants the opportunities to work within a team and use modeling to optimize building performance, and the competition gives conference attendees the chance to see what energy modelers do on a daily basis and learn from the teams' best practices and workflow. 

Review the team’s presentations:

43 l 40 (First Place)
Net Zero Heroes (Second Place)
MuZero (Fan Favorite)
Guardians of the Energy
Zero is the New Black
Gaia Samaritan
Energy Independence
Some Like It Green