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Flexlab rotates, transforms to test building energy waste

The Flexlab is the only facility in the U.S. that provides side-by-side, outdoor testing of integrated building systems — including  HVAC and lighting — in a completely reconfigurable space. It aims to help address shortcomings in traditional approaches to making buildings greener.

It is well-understood that buildings — commercial, industrial and residential ones alike — are energy hogs. They consume more energy than any other sector of the U.S. economy, are responsible for about 40 percent of carbon emissions and use 36 percent of the nation's electricity.

What is less well-understood, however, is the best way to make buildings more energy efficient, let alone how they might become an integral part of a demand response system stabilizing the electrical grid.

Each year, millions of dollars go into upgrading or designing buildings to make them greener. But these measures don't always yield the intended results.

"We have these issues of trying to close the gap between prediction and outcome. So there is some inherent risk in using these tools without knowing that they have been validated for that purpose," said Cindy Regnier, executive manager at Lawrence Berkeley National Laboratory's new Flexlab.

This is where the capability for low-energy experiments in Flexlab shines. Built with $15.7 million in stimulus funds from the Department of Energy, Flexlab simulates whole, tightly controlled building environments to test products and building systems.

Rotating test bed eliminates guesswork

That may actually sound easier than it is, said Regnier, who stresses that controls are a huge barrier right now: "Making sure we had an infrastructure in place that allowed us to bring in any kind of technology and any kind of control system and allow them to talk to each other was a real challenge for us. But it is what we designed and what we are getting."

Generally speaking, Flexlab strives to simulate instead of extrapolating. In order to do so, the planners at the LBNL came up with a unique concept that allows for one of the four newly built test beds to rotate up to 270 degrees. Together with different shading options, researchers can replicate almost any climate conditions in the U.S.

Rotating the test bed also can speed up testing by reproducing certain lighting conditions found throughout the seasons within a few weeks or even days. Each test bed consists of two identical cells, each 600 square feet, which allows for comparison testing. One new building is constructed in double-height to replicate the conditions of a big-box store. Flexlab can greatly modify all of the new structures: It can replace whole walls with windows, raise or lower floors as needed.

And everything can be measured, of course. There are sensors even inside the walls to help understand where the heat flow goes in a building. Every power outlet has its own electrical circuit and utility-grade meter.

"This kind of facility really breaks it down," said Regnier about the Flexlab. "We get a much more discrete amount of data that you would normally get in a building. We can understand both the very discrete energy consumption of the devices but also how they are contributing thermally to the environment."

Already in action

LBNL rents each cell for $3,000 per week, and the costs to reconfigure the space and for the actual testing come on top of that. "We think it is a pretty good value," said Regnier. "We think we are quite competitive."

Credit: Matthias KrauseEven before the official ribbon-cutting this week, Webcor Builders started the first private-sector project in the Flexlab. Together, Webcor and LBNL staff mocked up and pre-commissioned an office space in a 250,000-square-foot building for Genentech south of San Francisco. The building is already under construction, and Flexlab's rotating test bed will be used to test an innovative set of integrated façade, shading, daylighting, lighting and HVAC systems.

Another customer is California utility Pacific Gas & Electric, which is working on a package of solutions intended to achieve 20 to 40 percent energy savings over current code. The first experiment will center on envelope lighting and shading and will look at integrating them to save energy. A second test will be around HVAC systems. The results are also intended to help PG&E to design a new rate structure.

Regnier also expects to gain valuable insights into the role of systems in terms of prediction and outcome. "And there is a movement in the codes community to start thinking about how do we close that gap. Because right now, there is that performance gap where we say, something should perform like this, but quite often it does not."

According to Regnier, the codes industry is starting to be interested in moving towards outcome-based codes, meaning you are judged on the actual performance. "So how do we get from where we are currently to guaranteeing performance at a certain level?" she asked.

Looks like there are plenty of reasons why the new Flexlab should not stand idle any time soon.

Top image of simulators by Matthias Krause.

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