USN's Heating Systems

The Tibbot Center

The Tibbott Center, completed in 2003, uses geothermal heating as its main source of heating for the building. USN’s geothermal piping is located underneath the back field. Pipes are inserted into the ground and a ground source heat pump cycles water through an underground piping loop, providing the building with heat. Geothermal also works as a way to air condition. This reduces on the amount of coal needed to be burned to heat the building, reducing USN’s carbon dioxide emissions.

A video explaining geothermal more in depth

The presence of smog, caused by burning coal, has been shown to exacerbate rates of asthma attacks, emphysema, bronchitis, and cause lung damage. Children are particularly vulnerable to lung conditions caused by smog because they spend more time outside than adults and have smaller, developing lungs. The fact that USN is mostly heated by non-coal energy producers protects both the environment and the students.

More information on coal burning and its effects:

http://content.sierraclub.org/coal/
http://content.sierraclub.org/coal/burning-smog-soot-and-asthma

The Library

The library’s geothermal system is connected to the system in the Tibbott Center (see also description of the Tibbott Center). Both use the same geothermal field, which provides water to a separate manifold system for each building. The heating systems of the two buildings are controlled by a Building Automation System, which monitors both buildings from one main server. The library was completed in 2004, just a year after the Tibbott Center’s completion. ICC Thomasson designed both buildings.

ICC Thomasson is a design firm for mechanical and HVAC systems in buildings. They also offer energy surveys and audits to show companies how much energy they are consuming. According ICC Thomasson’s David B. Peters, the number of geothermal systems that they put in doubles every year. This system is frequently chosen for schools because it is permanent, environmentally friendly, and cost efficient. The USN geothermal project had both an emphasis on cost-efficiency and sustainability. They began working on the project in 2002, and, Peters says, it is still the most energy efficient system available.

Link to a video explaining geothermal:

http://energy.gov/energysaver/articles/geothermal-heat-pumps

The Main Wing

In 1925, a steam pipe was constructed running underneath Edgehill Avenue from Vanderbilt’s generator to heat the USN building. At that point, USN was still PDS (Peabody Demonstration School), which was a part of Vanderbilt. Even after USN was no longer the demonstration school, Vanderbilt continued to provide USN’s main building with heat from steam. In Dengel, Lamb, and Huber’s 1991 Appraisal of the USN Building, they mention the pipeline running under Edgehill Avenue as well as the fact that USN pays for the service on a pound by pound basis. It only powers the heating and cooling of this part of the building because that was the part of the school that was originally part of Vanderbilt. When USN expanded, the heating system from Vanderbilt did not also do so.

Vanderbilt’s generator originally burned coal, using four coal burning boilers. During the 1960’s, the system expanded to include two more coal-burning boilers. In 1980, efforts were made to stop the spreading of the coal ash by installing a fabric filter bag house (before this, the soot was released into the air). The coal caught in the filter was used as an additive for cement. The original system was later removed in 1988 and replaced with three new coal-powered boilers.

In 1988, a project to upgrade the existing steam system was approved. Vanderbilt installed its first cogeneration turbines in 1988 and 1989, respectively. In 2000, upgrades to the steam system were completed. In addition, heat recovery systems (HRSGs) were installed to use exhaust to generate more electricity and steam. Low-sulfur coal must be burned to heat the water and produce steam.

Recently, Vanderbilt has moved towards using a natural gas system. The first efforts to move towards this system occurred during the 1962, when one of the boilers was converted to a natural gas boiler and the other was allowed to idle. Both of these boilers were later removed. In 2013, the Nashville Post wrote about the Vanderbilt University’s Board of Trust voting to move from a coal powered system to a natural gas powered system. According to the article, this change would cost the university $29 million for the complete removal of the old steam system and the installation of two natural gas-fired boilers and one gas-combustion turbine. This plant produces 20% of Vanderbilt’s energy, the other 80% being sourced from the TVA. The produced steam provides for 90% of campus heating and 40% of campus cooling. The article quotes Chancellor Nick Zeppos, who said, “The use and design of Vanderbilt’s places, spaces and resources tells not only our history, but often the history of our nation. The decision to convert this facility to natural gas reflects the priority we place on conserving our environment and energy.”

The steam pipeline connection has been an important connection between Vanderbilt and USN for years, tying USN back to its roots as Peabody Demonstration school. In 1992, USN first planned on installing air conditioning because they believed that, “An adequate physical plant is an essential for providing the educational experience as described in our philosophy statement.” Three years later, USN installed an air-conditioning system to help attract potential students and parents of students.

Sources: Mr. Durnan interview, Vandy presentation, plant operations at Vandy PDF

The East Wing

In 1995, USN asked Jerold Panas, Linzy, and Partners Inc. for a study of the school in order to build a new East Wing. The East Wing is heated by a natural gas boiler. Natural gas is a much cleaner source of energy than coal. It is cost-efficient, energy-efficient, and more environmentally friendly than coal or oil.

Natural gas is composed entirely of methane, MH4. Burning it releases carbon dioxide and water vapor. This is known as a combustion reaction. A similar process occurs with coal, but coal releases a larger quantity of carbon dioxide (which contributes to greenhouse gas emissions), sulphur dioxide (which contribute to acid rain), and nitrogen oxides (which contribute to “smog” typically associated with cities). Usage of natural gas also decreases air emissions; according to the American Gas Association, natural gas releases about 117,000 pounds of air emissions per btu of energy, while coal produces roughly twice that amount. Natural gas is also more energy efficient than coal; 90% of natural gas power reaches the consumer, while only 30% of energy from conventional energy production actually reaches the consumer.

After the East Wing’s completion, USN built an air conditioning system into the newly constructed wing. It uses an electrically powered, 190 ton chiller. USN’s electricity is sourced from Nashville Electric.

Historical Contexts

Renovations at USN reflected the historical contexts of the time period. In the 1980’s and 90’s, environmentalism began to move away from the grassroots efforts of the Rachel Carson era and almost entirely shifted to institutional change. The EPA began to exercise its power in the late 1970’s, and the World Wildlife Foundation expanded (http://sovereigntyonline.org/p/gov/rise/g_part06.html) during this time and the early 80’s. The first Vienna Conference on Ozone Depleting Substances was in 1985, suggesting a graduation of environmentalism from exclusively grassroots movements to government decisions. (http://www.lib.niu.edu/1990/ii900413.html). The groundbreaking Montreal Protocol occurred in 1987, bringing international attention to the fact that human activity produces substances which directly relate to ozone depletion. While the decision to install a geothermal system at USN may have been entirely cost-based, it is easy to imagine the historically liberal USN administration considering the environmental trend in influential institutions before making their decision.

In the 1990s, USN consisted of three buildings: the PDS building (built 1924), the West Wing (built 1985), and the Sperling Building (built 1989). In 1991, the USN board of directors asked Dengel, Lamb, and Huber to write an appraisal of the USN facility. During that time, USN’s gas came from Nashville Gas and USN’s electricity came from Nashville Electric. The report makes mention of the pipeline under Edgehill Avenue providing heat to the main building, and that USN pays Vanderbilt a premium on a pound per pound basis. On June 30, 1995, USN asked Jerold Panas, Linzy, and Partners Inc. for a study of the school in order to build a new East Wing and a new Fine Arts Center, as well as to renovate the high school floors of the Main Building and the Lower School Classrooms. During the early 2000s, renovations to the Tibbott Center and the library were completed. In 2011, USN renovated its cafeteria, which is now LEED certified (to read more about LEED certification, click here) This included the completion of the geothermal system underneath the back field. The facilities completed during the 1990s and the 2000s are the same as those that exist today.

USN’s modernization of an older building follows a trend of retrofitting. As schools need to modernize, increasingly instead of reconstructing the old facilities, the school will modernize the older building. Schools like Harpeth Hall and Franklin Road Academy have undergone large renovation and expansion programs. Since June of 2011, Montgomery Bell Academy has constructed 65 geothermal wells on their athletic field at Harding Road. The geothermal system is used at MBA to heat and cool new extensions being built during the same time period. ICC Thomasson representative David B. Peters says that geothermal in schools is growing rapidly. If schools have available ground space, geothermal is easy to install without completely demolishing the original school building(s).