3 FM quick reads on Net-zero energy
1. Closing Windows For Energy Savings
Today's tip is about a lesson learned from a facility manager at a net-zero energy building, who learned just important occupant training is for energy-savings goals.
The following anecdote from Shanti Pless, senior research scientist for the National Renewable Energy Laboratory's (NREL's) Research Support Facility (RSF) in Boulder, Colo., illustrates the importance of continuous occupant training, especially in ultra-energy efficient buildings. (The RSF's 330,000-square-foot facility is the largest net-zero energy building in the world.)
Pless says that the building automation system is designed to send a notification to occupants' computers if the temperature in the building is hot or cold enough that they should close the facility's manually operable windows. He says some occupants thought the pop-up was a notice from IT telling them they needed to close windows on their PC, because they didn't know how the building itself would be telling them to close the actual windows.
While that was an isolated (and fairly amusing) incident, it does emphasize the importance of training. Pless and his team put together an eight-page occupant manual explaining how various aspects of the ultra-efficient building work.
Pless emphasizes, however, that you don't want to put too much faith in occupant training. "You really have to train occupants," he says. "But training is the last line of defense. Training's good, but remember, you'll have to do it continuously forever." Shanti explains that occupants tend to revert back to previous behavior, and so it's up to facility managers to constantly remind them how their actions can affect the building's energy use.
The best-case scenario, says Pless, is if the occupants don't have to do anything out of the ordinary, or anything they'll consider to be a hassle. The best testament to a building is if the occupants talk proudly about being in a net-zero energy building, and how easy it is for them.
3. Understanding What A Net-Zero Energy Building Really Is
Today's tip is about the industry-standard definitions for various types of net-zero energy buildings. As net-zero energy buildings increase in prominence - with the expectation that they'll be code-mandated some time in the future - standard definitions for what exactly makes a net-zero energy building are critical.
Currently, there are four main types of net-zero energy buildings. Let's take a look at each.
1) Net-Zero Site Energy buildings is the most common type. This is a building that produces at least as much energy - through on-site renewables - as it uses on a yearly basis. 2) Net-Zero Source Energy buildings are buildings that produce as much energy as they use when calculated at the source. What that means is that the building's produced energy must also make up for energy lost in transmission from the source of the energy the building does use. 3) Net-Zero Energy Cost buildings are those in which the amount of money an owner pays for electricity a building uses is equal to the amount of money the utility pays the owner for renewable energy the building feeds to the grid. 4) Net-Zero Energy Emissions buildings produce and export at least as much emissions-free renewable energy as they import and use from emission-producing sources on an annual basis. According to sources, this is the easiest type of net-zero energy building to achieve, and therefore may be the least environmentally stringent.
Strictly speaking, these definitions do not include buildings that purchase renewable energy certificates (RECs) or carbon offsets to make up a gap between a building's energy use and its production. Nor should buildings that use of those make-up measures be included, say most experts. But stayed tuned as these definitions evolve.