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[caption id="attachment_51980" align="alignright" width="400" caption="Drilling trucks and equipment designed to separate mud from drilling water for recycling are part of the process for installing a ground loop field for commercial or residential customers."][/caption]

NORTH BAY -- With high heating oil, propane and electricity prices, more commercial and residential building owners -- as well as municipalities and school systems -- are considering geothermal ground source heating and cooling as an alternative.

Interest in this energy-efficient, environmentally clean and cost-effective technology is also on the rise due to 2010 CalGreen building code requirements (Part 11, of the California Code of Regulations, Title 24) mandating a reduction of greenhouse gases by 3 million metric tons by 2020.

[caption id="attachment_51981" align="alignleft" width="315" caption="Heat exchange pumps above ground extract energy from water to provide building heat in winter and cooling in summer."][/caption]

 “There are some 15,000 to 20,000 operating geothermal systems in Pacific Northwest service areas and perhaps half as many more in California,” according to John Geyer, a geothermal consultant and certified geothermal designer in Vancouver, Wash. “The national growth rate is between 10 and 15 percent a year.”

“The key to geothermal heating and cooling’s 300 percent to 500 percent efficiency, relative to grid power consumed and operating cost savings, is that grid power is only used to drive the loop-water circulating pump, the refrigeration compressor and the forced air blowing fan. External fuel is not used to create or dissipate heat.”

Geothermal heat exchange systems cost two-thirds less to operate compared with propane or fuel oil costs per year -- with no harmful emissions.

They also offer the fastest payback -- less than five years to 10 years -- among energy-saving systems such as fuel cells and solar, and have the longest life cycle, up to 50 years. Geothermal can reduce energy loads by up to 30 percent to 60 percent.

According to industry statistics from www.geoexchange.org, heat pump shipments have jumped from fewer than 11,000 units in 1983 to 112,000 units shipped in 2011.

Legislation passed by Congress in 2009 offers homeowners a federal tax credit of 30 percent of any geothermal system installed by Dec. 31, 2016, and commercial projects may deduct 10 percent. Both credits apply toward defraying equipment and installation costs.

This form of geothermal energy is not to be confused with electricity produced at the Geysers when natural steam (or steam resulting from water injected into deep wells to reach hot rock layers above lava), rises to the surface to power turbines.

Instead, geoexchange technology uses a field of subterranean tubing, called a ground loop, to extract low-grade heat energy from water circulated underground, taking advantage of the earth’s near constant temperature of 55 to 65 degrees Fahrenheit.

The ground acts as a heat source warming a building in winter, and a heat sink to provide cooling in summer, with the aid of a water source heat pump, called a heat exchanger, on the surface.

Loops can be installed horizontally or vertically underground or on the surface in a pond, lake or irrigation water holding tanks.

A major North Bay geothermal installation was completed in March at the Buck Institute for Research on Aging in Novato.  

PAE Engineering was the consulting firm under contract to Trison Construction for the Buck project. Some 325 bores were drilled to a depth of 400 feet containing miles of high-density polyethylene tubing one to 1.25 inches in diameter. 

This technology will also result in conserving almost 18,000 gallons of water a day (seven million gallons per year) while reducing the institute’s annual carbon footprint by 53 percent.

Some 2,484 metric tons of carbon emissions will be eliminated annually. Greenhouse gas savings are comparable to taking 9,738 vehicles off the road, while also saving $436,000 a year in energy costs.

At the George Lucas’s Big Rock Ranch in Marin County, the new 185,000 square-foot Lucasfilm’s office and entertainment complex also utilizes a modern geothermal system installed by Earth Energy Systems, a firm later purchased by Air Connection.

An even larger system is part of the proposed 270,000-square-foot digital movie studio at Mr. Lucas' nearby Grady Ranch. The Marin County Board of Supervisors on Tuesday is set to consider an appeal of the project.

Beth and Mark Morelli, owners of Santa Rosa-based Air Connection, started their business 16 years ago focusing on HVAC. They expanded the firm’s services in 2002 to include in-floor radiant heating, pool heating and geoexchange systems.

Air Connection has designed and installed 15 commercial and 12 residential geothermal projects in the Bay Area with more to come -- including the new 49er stadium in Santa Clara in cooperation with ACCO Mechanical, provider of the heat pumps.

Air Connection’s list of North Bay projects includes a retrofit of the existing HVAC system and rooftop gas-electric units at the Sonoma County Water Agency’s operations and maintenance engineering building in Santa Rosa.

Meline Engineering of Sacramento was the engineer of record for the ground heat exchanger and interior mechanical systems design. Air Connection installed the exchanger and Bell Products of Napa installed the building mechanical system for the water agency.

Other Air Connection projects include: The Valley of the Moon Observatory Association and the Justi Creek Vineyards in Glen Ellen, the Beringer Vineyards Rhine House and the Napa Valley Vintners Association in St. Helena, as well as the Ratna Ling Retreat in Cazadero, Stone Edge Farm Vineyards in Sonoma, along with the Bardessono hotel and spa and the Town Center in Yountville.

The refurbished Yountville unity Center also has a geothermal heat exchange system. 

With stringent rules regarding the disposition of runoff water and underground construction waste, Air Connection uses special machines to process and recycle drilling fluids. They designed unique stainless steel tubs to capture water around boreholes.

One machine, called a “MudPuppy,” from Tibban Manufacturing, Inc., of Apple Valley, filters and screens muddy water from drilling operations.

Water then goes to the “Mud-X” centrifuge, designed by Air Connection and built by Kem-Tron Technologies, that separates the remaining mud. Clean water is recycled to the drillers for re-use.

A third device being developed by Air Connection will dry mud so that its moisture content can be accepted by landfills, if not returned to help restore drilling surface areas.

Several other firms are also designing and installing geothermal heat exchange systems.

Quattrocchi Kwok Architects designed the American Canyon High School in Napa, with mechanical systems provided by Costa Engineers. Chaudhary & Associates performed civil engineering work for the school’s geothermal system.

Riechers Spence & Associates was the civil engineering firm for the Blue Oak Lower School in Napa. Enlink Geoenergy of Rancho Domingo installed the geothermal system at Blue Oak and also conducted test bores for the Buck Institute.

“Horizontal and other alternative geoexchange systems can also function effectively,” said Hugh Linn, president of Reichers Spence & Associates civil engineering in Napa. 

“We designed an experimental system for an estate home in Calistoga. This system piggy-backs on the existing vineyard irrigation system. Irrigation water from storage tanks was transported to a heat exchanger in the home. In summer, when vineyards are irrigated, the system provides constant 55 degree water to the home heat pump.”

According to the U.S. Environmental Protection Agency, more than 1,500 schools and colleges use heat pump technology. 

Michael Lucas, P.E., now with PAE Engineering, was the design engineer for the geothermal ground loop system at Santa Rosa Junior College’s Lawrence A. Bertolini Student Center, for two College of Marin campuses in Indian Valley and Kentfield as well as for Ohlone College (platinum LEED-certified) in Newark.

“Land close to bodies of water, or with active lateral water movement in the earth, is among the ideal sites for geothermal,” said Mr. Lucas. “You get the best heat exchange with ground water that moves. This is why it is vital to conduct test bores to see if conditions are right for geothermal exchange.”

While many municipalities are familiar with geothermal technology and price local fees and drilling permits accordingly, California Department of Water Resource’s standards have remained in draft form since 1999, which has created confusion in many parts of the state. 

In other jurisdictions, rules and fees relating to water wells or the oil and gas industry are being erroneously applied to “closed loop” geothermal boreholes, experts said. New guidelines are needed for regional Water Quality Control Board Districts, they said.

To address these concerns, the newly formed California Geothermal Heat Pump Association (CalGeo) is sponsoring Assembly Bill 2339, the Renewable Thermal Energy Deployment Act, co-sponsored by Assemblymembers Das Williams and Manuel Perez.

Santa Rosa-based California Groundwater Association and groups such as the U.S. Green Building Council in California also support the bill.

AB 2339 would update geothermal heat exchange well standards and minimize impediments to the use of this energy-saving technology.

“Since April 2010, the CGA has been working with the Water Well Technical Advisory Committee and the California conference of Directors of Environmental Health to update standards originally established in the mid-1990s under AB 2334,” said Phil Henry, a geo-industry consultant with GeoExchange Solutions. “This proposed legislation is both budget and politically neutral.”

AB 2339 has been sent to two Assembly committees for review, the Utilities and Commerce Committee, chaired by Assembly Member Steven Bradford, and the Natural Resources Committee, headed by Assemblyman Wesley Chesbro.

Some 1.5 million heat pumps are operating in the U.S. today and more than 1 million homes have geothermal heat-exchange systems.

For more information, go to www.geoexchangesolutions.com, www.geoenergy.org, www.igshpa.okstate.edu and www.epa.gov/region1/eco/energy/re_geothermal.html.