Nothing but net - zero
July 1, 2009
SAN FRANCISCO - The clock is ticking. The U.S. Department of Energy is mandating that all new commercial buildings be “net-zero” by 2030.
What is a net-zero building? The definition is open to interpretation, but ASHRAE defines it as a building that “annually uses no more energy from the utility grid than is provided by on-site, renewable energy sources.”
With that goal in mind, the American Society of Heating, Refrigerating and Air-Conditioning Engineers held its first energy conference on the topic March 29-31 in San Francisco. The slogan of the event, which ASHRAE hopes will become an annual one, was “Countdown…Net-zero and beyond.”
Terry Townsend, ASHRAE’s past president and chairman of the conference, told attendees that the three-day event would be a “roller coaster of information.”
He said the roster of speakers for the event would share strategies on building and designing net-zero facilities that “actually work.”
“We’re going to launch you to a sustainable future,” Townsend said. “The world is waiting for the United States to do something.”
Taking actionCurrent ASHRAE President Bill Harrison was the first official speaker for the conference, and he shared why successfully building net-zero energy facilities is a priority for the society.
He pointed out that atmospheric carbon dioxide levels will continue to rise. Global carbon dioxide emissions are currently at 30 billion metric tons. And by 2030, carbon dioxide emissions are projected to be 42 billion metric tons.
“Can we as a global society take a chance of business as usual?” Harrison asked.
The Energy Department is not going about business as usual. Dru Crawley from the department’s building technologies program mapped out its energy goals and why energy efficiency is so important.
He said such programs will provide more jobs, lower operating costs and reduce the strain on power grids.
To make sure this goal is accomplished, Crawley said the Energy Independence and Security Act of 2007 called for the development of net-zero commercial buildings by 2030. But the Department of Energy is not stopping there. By 2040, the department wants 50 percent of all commercial buildings to be net-zero with the remainder to follow by 2050.
The federal government wants to make sure that the department can accomplish its goals. Under the Recovery and Reinvestment Act signed into law in February, $16.8 billion will go to efficiency and renewable energy programs.
Crawley said this a 10-fold increase in federal funds for energy efficiency, and the bulk of this funding is going to grants and rebates.
“While research is showing net zero is possible, there is still a long way to go,” he said. “Many states do not meet (the energy requirements of) ASRHAE 90.1.”
Standard 90.1 sets the minimum recommended efficiency levels for most commercial buildings in the United States and around the world.
The state of California, often a national trendsetter, is trying to do its part when it comes to net-zero buildings. Dian Grueneich from the California Public Utilities Commission told attendees that the Golden State wants to be a “national model” for energy efficiency.
“Changing buildings is the No. 1 thing to deal with global warming,” she said.
And California is taking it very seriously. The state spends $1 billion a year on energy-efficiency programs, one-third of all the funding used across the United States, Grueneich said.
Not only does California want to meet the DOE’s 2030 deadline for commercial buildings, it wants all new residential construction to reach net zero by 2020. Grueneich said the only way to get this accomplished, not just in California but in every state, is to convince lawmakers and the private sector that net-zero energy buildings are important and viable.
Making it happenAfter making the case for net-zero facilities, ASHRAE wanted attendees to see that the concept can be a reality.
Representatives from the DOE’s National Renewable Energy Lab in Golden, Colo., were on hand to talk about the laboratory’s research on energy efficiency and net-zero buildings.
“Commercial sector energy use is growing at 1.6 percent per year,” said Paul Torcellini, team leader for commercial building research at the lab. He explained that the growth in commercial energy is outpacing energy-efficiency solutions.
Torcellini said the lab has been researching the “what-if scenarios.” He said that new buildings must be constructed with ASHRAE’s energy guidelines in mind. Torcellini also said to improve the efficiency of existing buildings, new mechanical systems or applications are not the immediate answer.
Buildings must find strategies to decrease energy consumption by 60 percent to 70 percent before adding on any new systems. He explained that in many cases, building officials just add another system to try and solve the problem. But if energy usage is not addressed, it could have the opposite result.
As for design, Torcellini said that engineers must focus on the building “envelope.” This means well-insulated roofs, walls and floors. The envelope must also meet the load requirements for day lighting and passive solar heating.
Other strategies include choosing HVAC systems that can handle the heating or air-conditioning load for specific climates.
Shanti Pless, a research engineer for the NREL commercial building team, added to the discussion. Pless said that when it comes to net-zero energy buildings, “zero is not easy to define.”
More specifically, he said that a net-zero energy building doesn’t mean that the building doesn’t use energy. It can just mean that the building is meeting all of its energy needs from renewable sources or has net-zero emissions. It can also mean that the building has no adverse impact on the utility grid or the environment.
“There’s lots of room for interpretation,” Pless said.
The answer is finding a definition that works for the engineer and finding a way to get there.
Finding the wayRon Judkoff brought what he said was proof net-zero energy structures are possible.
Judkoff manages the NREL’s building and thermal systems center, and he provided examples of buildings that are currently functioning as net-zero facilities. They prove that net zero can be accomplished, he said.
Two years ago, NREL helped to design a net-zero energy home to be built by Habitat for Humanity. The one-story home in Wheat Ridge, Colo., was built with an R-60 roof and R-40 wall insulation, four photovoltaic cells, a domestic solar hot water tank and a heat-recovery system.
NREL has been monitoring the home for the past two years and found that it has been generating more energy than it uses. Judkoff also discussed other systems that will help to reach the net-zero goal. These include compressorless cooling systems and photovoltaic ventilation.
“These are game-changing technologies,” said Judkoff.
But the systems are meaningless if they are not employed correctly, experts said. Bing Liu, senior researcher with Pacific Northwest National Laboratory in Richland, Wash., explained how ASHRAE’s design guides could be used to achieve energy efficiency.
ASHRAE has published a series of energy guides to help engineers achieve the DOE’s efficiency goals.
Liu pointed out that the building sector uses almost 40 percent of all energy in the United States. Eighteen percent of that energy is used in commercial buildings. That is why the DOE has created a net-zero “roadmap.”
The DOE knows that net-zero buildings will not happen overnight. That’s why the department has put benchmarks in place: By 2010, all new commercial buildings must achieve 30 percent energy savings over ASHRAE Standard 90.1 levels. Small to medium-sized commercial buildings will need to reduce their energy consumption by 50 percent by 2015 and 70 percent by 2025.
“Improving the envelope of the building will go a long way to achieving zero energy,” Liu said.
Other technologies include dimming controls, which will shut off lights in a building when they are not in use or they are not needed.
With HVAC, Liu said that the ASHRAE guides cover higher-efficiency unitary equipment, demand-control ventilation, motorized outdoor damper controls and heat pumps.
But one of the most important things building owners can do is to consider unplugging.
She explained that buildings waste tons of energy just from leaving appliances and other equipment plugged in while they sit idle. One solution is to employ motion-based plug strips. When someone is not in a room, the electrical strips will turn off.
“Part of the problem is motivating people to get involved,” Liu said.
Selling net zeroAnd motivation means selling consumers on the benefits of energy efficiency and net-zero levels.
David Springer of the Davis Energy Group in Davis, Calif., talked about the strategic plan of the California Public Utilities Commission, which includes ensuring all residential buildings in California are net-zero by 2020.
It might seem like a tall order, but Springer believes that there are possibilities. As many know, the state’s housing market is in a recession and many builders have put new projects on hold.
That is not entirely bad. According to Springer it allows builders to “evaluate where we are.”
However, the challenge is to get builders to rethink their building incentives.
“It’s hard to get builders to do new things,” Springer said, because most buyers don’t understand energy-efficient mechanical systems.
“Homeowners don’t understand it,” he said. “They’ll opt for the granite countertops instead.”
To give buyers and builders something to think about, the Grupe Co. started construction on a new residential space in Rocklin, Calif., that will consist of 144 Leadership in Energy and Environmental Design-certified homes.
Forty of the homes have been finished and the mechanical systems feature a variable-speed condensing furnace, air conditioners with a 14 seasonal energy-efficiency rating, a ventilation cooling system and a tankless water heater.
As for installation, the ductwork was tested to make sure there was less than 6 percent leakage.
A simulation was run on the 40 homes and researchers found that over $1,400 could be saved in utility costs. This is a 40 percent savings over other residential buildings in the area.
And while the housing market tries to recover, Springer suggests that existing homes be the focus for accomplishing energy savings. He encouraged attendees to look at better diagnostic tools for finding duct leakage. He also said that better insulation and window retrofits would be helpful.
But as other speakers said, reducing energy has to start with addressing behavior. Consumers and building owners must want to change their habits when it comes to energy usage. Much of the battle may be in educating consumers to buy the products, undertake the new projects and unplug energy-eating appliances.
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