|
An image of the Boston skyline taken with the MIT researchers' thermal imaging system. Credit: Long Phan.
|
Getting an energy audit of a home or a
commercial building can be a time-consuming and labor-intensive process. But
new techniques and technology developed by a team of MIT researchers have
streamlined the process, allowing for scans of large groups of buildings and
even entire cities.
The project uses a vehicle with
automated cameras that take thermal infrared images of every building as it
moves along. Researcher Long Phan and Research Scientist Jonathan Jesneck,
working with Professor Sanjay Sarma, developed the system, which they have used
over the last few months to scan the entire city of Cambridge
and an army installation (Fort Drum in New
York).
The idea is to identify the buildings
that are most inefficient, by detecting the heat escaping through walls, roofs,
doors, and windows in a way that allows detailed, quantitative comparisons of
the rate of heat loss. That will make it possible to target remediation efforts
at the worst buildings, thereby getting the most out of any efficiency-improvement
spending.
Phan says that many existing programs to
improve home energy efficiency throw money uniformly at the problems with no
verification process to measure the actual energy-use improvements that
resulted in savings.
As Sarma says, that approach is “like
saying there’s a heart-disease problem in the city, so everyone should take
aspirin.” Instead, he says, this system would identify which houses could
benefit the most—in effect, saying “this man doesn’t need an aspirin, but that
one needs two.”
The new approach will make it possible
to “identify where the energy gushers are,” Phan says, so that efforts can be
directed where they will have the most impact. To do that, the team has
developed “a non-invasive, high throughput remote energy diagnostics system,”
he says.
That “non-invasive” aspect is a key
difference from typical home energy audits, which often take a few hours and
involve inspecting every part of the home and often require special equipment
to measure air leakage. Even then, while such audits can determine where the
energy losses are and suggest ways of reducing them, they do not provide
quantitative estimates of the projected savings resulting from a given change.
The new process begins by photographing
buildings with a system the team developed to get high-resolution, long wave
infrared images using an inexpensive, low-resolution camera. Normally, the cost
of high-resolution far-infrared cameras is prohibitive for such widespread use.
As a substitute, the team developed a novel patent-pending technology called
“Kinetic Super Resolution” that uses a computer to combine many different
images taken with an inexpensive low-resolution IR camera, which produces a
high-resolution mosaic image.
“We needed to develop new methods” to
improve resolution, Phan says. The technique is similar to systems developed by
NASA to produce enhanced resolution from images taken by robotic spacecraft on
other planets. As a result, “we can now break the cost barrier” for widespread
use of thermal imaging, he says.
They are also developing software that
would then translate those images into an estimate of the costs of making
improvements, and the return-on-investment that would be achieved by doing so.
To do this, they have enlisted the help of a local company called Green Guild
that does energy audits and retrofits, tapping into the company’s database on
the costs of the work done and resulting energy savings. They have also used
online home-improvement stores’ listings to compile a database of the costs of
all the materials needed for such work.
Last summer, Boston Mayor Thomas Menino
announced plans for a scan of every single building in that city. Boston “wants to be the
green city of the world,” Phan says, “to show they can turn a very old city
very green.” That project, which the team still hopes to carry out, is awaiting
funding.
Gabe Shapiro, director of community
relations for a nonprofit group called Next Step Living, says that “Being able
to show vivid images of uninsulated walls and air flowing in from gaps in their
home's envelope is one of the most powerful motivators that drive customers to
adopt weatherization recommendations.” But that only happens if people know
they can get such images. “Projects like the one that the MIT team is
undertaking in the city of Boston
allow for targeted outreach to homes with high-savings potential through
sharing of exterior infrared images. These images displaying obvious areas of
heat loss will undoubtedly drive the residents who need it most to get their
homes assessed and take the necessary steps to make their homes more energy
efficient.”
“We want to not only determine where
these leaks are, we want to fix the leaks and verify the energy savings,” Phan
says. “We’ll provide a numerical solution, saying your window is leaking this
much, and costing you this much in energy."
The citywide scanning of Cambridge, which had to
be done at night in wintertime in order to see the effects of heated air
escaping from buildings, has just been completed. “There is big potential
here,” Phan says. “If you could make homes even 2% more efficient, that
translates into billions of dollars saved.”
SOURCE
