Grounded in energy alternatives
Renewable and sustainable energy resources are on the minds of U. S. citizens from grade school children to grandparents, and are at the forefront of consideration and action among politicians, scientists, engineers and investors.
A national goal to produce 10 percent of this country’s electricity using renewable resources by 2012 increases to 25 percent in 2025. Solar and wind power, so-called “green” technologies, are being pursued with vigor, but less attention has been focused on a resource that is literally lying at our feet: geothermal energy.
The American Reinvestment and Recovery Act earmarks $350 million for geothermal research, design and development. And $50 million of that investment is aimed at ground source heat pumps, technology that Yunsheng “Shawn” Xu has championed for most of his career as an engineer, both in his home country of China, and now as a research associate professor in civil and environmental engineering at the University of Missouri.
Xu, director of the Chinese chapter of the International Ground Source Heat Pump Association, served as an energy advisor on the construction of the 2008 Olympic facilities in Beijing, China.
“When I first made my presentation to the Beijing Olympic committee staff and city government officials,” said Xu, “I pointed to the ground and told them, ‘to you this is soil, but to me this is oil.’ There was great concern that it would not work and some pushed for a backup system.”
But in the end Xu’s support and confidence in geothermal heat exchangers prevailed. “Major Olympic buildings in Beijing, including the Olympic Village, National Olympic Stadium (Bird Nest) and the Olympic Forest Park use geothermal with no backups — no fossil fuels.”
Though ground source heat pumps have been in use since the 1940s, attention is more often focused on the fact that installation adds to initial construction costs, and less on the fact that systems pay for themselves in energy savings over a period of five to 10 years. Geothermal systems are up to 70% more efficient than natural gas — and will have a system life twice that of an air-source system, according to Xu.
Because successful ventures like the Olympic installations are not well publicized, skepticism on the part of architects, builders and investors remains high, or as Xu says, borrowing an old Chinese idiom, “No one wants to be the first to eat the crab.”
Generally the procedure to install ground source heat pumps involves drilling several bore holes 200 feet into the ground to accommodate the water filled plastic coils used to regulate heating and cooling temperatures. However, Xu has devised a simple machine to install the heat transfer system horizontally. His system requires more bore holes, though at a much shallower depth.
“My system takes one-third of the time to install and can be done at one-third the cost, and can provide more energy than a house needs,” Xu said, adding that geothermal efficiency increases when a system is installed that will service a number of homes, or a development, rather than a single unit.
Xu insists that the consideration to use geothermal energy should precede construction and that it is best to get the developer involved before he goes to an architect. His attentions are focused on commercial applications, including some innovative applications of the technology.
“I don’t generally work with small single units. I look at large commercial districts,” Xu said. “I worked on a 10-floor, five-star hotel (in China) that had to be built on pilings for support. I put the heat transfer system in the pilings. It is five to six times more efficient than regular bore holes.”
“We just completed a geothermal project in Shanghai, a 370,000-square-foot American school with six buildings, including an Olympic standard gym,” said Xu. “A system under the soccer field provides 100 percent of the school’s heating.” He adds that the buildings’ rooftop gardens can moderate heat flow through the roof and reduce the energy demand for air-conditioning in spring and summer.
These projects are small compared to one Xu has been discussing with developers and investors in China to build an entire district the size of Columbia, Mo., in Nanjing. The development would include hotels, condos, shopping centers, office buildings, restaurants — all the amenities of a small city — and all would use geothermal energy. Xu, who is providing technical overview for the project, is working with a group of several investors as they conduct a feasibility study.
Xu’s success convincing Chinese investors and developers to use geothermal energy can in part be attributed to careful efforts to document systems he has installed. He hopes to transition to more geothermal energy installations in the U. S.
“Training can be a vehicle for new technologies,” Xu said. Last spring he worked as a teacher/trainer with a program in St. Louis to provide displaced veterans with job training focused on the construction of green buildings, including geothermal and solar technology installations. Mizzou Engineering’s Institute for Energy Technologies (ENTECH), and Veterans for Energy Transformation and Sustainability Solutions (VETSS) cosponsored the program along with Belcher Homes and ANSWERS, Inc. A skilled workforce trained in the areas of sustainable energy construction is essential for green technologies to be implemented.
“I have two proposals in the works. One is a net-zero energy farm in Cooper County, and the other is a 21-acre shopping center in West Plains, Mo.,” said Xu, the latter a project that could demonstrate a system that will cut businesses’ energy costs in half. “I like projects that can be linked to economic development.” A recent story in the “St. Louis Post Dispatch” profiled Xu and his plans to build his family a 2,600-square-foot “zero energy” house west of Columbia that will incorporate passive solar, solar panels and a geothermal system installed beneath the gravel driveway.
“I plan to write a book about building a home that will show a ‘regular’ house and a home with a geothermal system and the savings it can provide,” said Xu. “The best way to save energy is to build as much as you need, not more. Otherwise, energy is wasted and so are materials.”
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