San Diego, Dec. 11, 2008 -- The National Aeronautics and Space Administration (NASA) recently held an international workshop aimed at “enhancing mission through proactive environmental risk mitigation,” organized by a Jacobs School of Engineering alumnus and hosted by the UC San Diego division of the California Institute for Telecommunications and Information Technology (Calit2).
One of NASA’s goals for the annual workshop is to look within and beyond the borders of the United States for situations that could impart risk to various NASA programs, according to David Amidei—a NASA environmental engineer and UC San Diego alumnus (chemical engineering, 1984). NASA then works with partners from around the nation and the world to find solutions to those risks.
“The point of the conference is to get together with collaborators and focus on current and potential projects…to kick the stones out of the road before the various programs even know the stones are there,” said Amidei. “Space stations are a high profile example of international collaborations NASA is involved in, but these collaborations happen on a much more ground-level basis as well.”
Amidei played an important role in bringing this event to the UC San Diego campus. In 2007, a university in Portugal hosted the annual workshop that is organized by NASA and a Portugues environmental research center, and the freshness of the student questions and the vitality and aura of the facility impressed Amidei. Thinking of where to hold the workshop in 2008, Amidei thought, “I know where to go get some of that enthusiasm!” He re-established his connection with UC San Diego and helped bring the workshop to campus.
Paul Linden, professor and chair of the Department of Mechanical and Aerospace Engineering (MAE) and Jan Kleissl, an MAE professor, were among the presenters at the workshop. Linden’s talk focused on the use of sustainability concepts to reduce risk. Kleissl spoke on green engineering for urban heat island mitigation.
“The most impressive thing that I have seen at UCSD this week in terms of sustainability is the integrated systems approach the campus is taking,” said Amidei.
“One example that comes to mind is UCSD’s integrated approach to dealing with the waste methane out at the Point Loma landfill. I’m impressed by how campus officials stepped through the decision making process of what to do at a specific moment with that methane. Do you generate electricity? Hydrogen? Do you use it right away? Store it? I see the same kind of integrated approach is being taken with UCSD’s microclimate analysis and smart landscape watering projects.
“These activities themselves are important, but at a higher level, it’s the integrated approach itself that impresses and interests me,” said Amidei.
Urban Heat Islands
Kleissl is taking this kind of approach to his studies of urban heat islands (UHI), which are metropolitan areas that are significantly higher in temperature than surrounding rural areas. Kleissl has studied the phenomenon extensively and says the UHI effect has three main causes: modification of the land surface by urban development (e.g. asphalt that absorbs a lot of heat); reduced water availability; and waste heat generated by energy production and usage. Without the UHI effect, Kleissl estimates Los Angeles would be 5 degrees Fahrenheit cooler on average. Moreover, in a changing climate, the UHI effect will be strongest on the hottest days during Santa Anas – making them even hotter, and fire danger even greater.
Kleissl’s lecture focused on how organizations can reduce energy consumption and save money by enlisting smart building practices, including the use of white or reflective materials to build roofs, pavements and roads, or grouping buildings so that they shade one another.
Another “green building” option involves landscaping. Kleissl and graduate student Neda Yaghoobian have studied the effects of grass and artificial turf, with the idea that a “green belt” surrounding a structure will absorb and reflect thermal energy from the sun. Most people know that irrigated lawns or wetted sand on the beach are much cooler to the touch than artificial turf, whose temperature is similar to concrete or dry sand. But Kleissl’s research on landscaping and UHIs has proven to be somewhat counter-intuitive. He has discovered, through multi-scale modeling of UHIs, that artificial turf, rather than grass, is actually more effective in keeping nearby buildings cool, because turf tends to absorb more solar heat and store it in the underlying soil, while grass reflects more to the building walls. However, compared to grass, turf emits more heat into the larger surrounding area — which Kleissl says may tip the balance in favor of grass in terms of overall energy efficiency.
Then again, grass requires water, and in dry climates and droughts like currently in San Diego, that may be more important.
“Opposing local and regional or global effects are a classic environmental problem,” Kleissl says. “It’s similar with power plants: You can choose not to build a smokestack and pollute mostly the surrounding neighborhood, or you can build a smokestack and pollute a larger area at lower concentrations. Personally, I’m always in favor of what’s the overall best for the world.”
NASA’s interest in environmental risk mitigation goes much deeper than smart coatings and fuel cell technologies for spacecraft -- the Administration, as evidenced by its recent workshop held at UC San Diego, is also looking into ways it can reduce the environmental footprint of its ground operations. After all, more than 99.9% of NASA employees are grounded on earth at any given time.
2008 Workshop Agenda