In December 2006 - following a year of testing an installation at a nursing home in Florida - the U.S. Environmental Protection Agency (EPA) released an Environmental Technology Verification (ETV) report confirming 400% efficiency of the EarthLinked® Commercial Water Heating System. The hybrid system combines a high efficiency geothermal heat pump with a standard commercial water heater tank.

"Energy savings at the nursing facility were dramatic," said Richard Adamson, director, Southern Research Institute's Greenhouse Gas Technology Center for the EPA's ETV program. The researcher's role for the EPA was to provide professional, third-party verification of equipment performance in real-world conditions. "The manufacturer claimed an expected energy saving of 70 %. We found it exceeded that at this site."

According to Adamson, they confirmed that renewable energy from the earth reduced electric energy consumption for water heating by 75 percent at the Lake Towers Retirement Community in Sun City Center, Florida. One of the facility's buildings served as the test site

Tests occurred at the Sun Terrace, a one-story building with two residential wings for assisted living. Each wing has 50 rooms, each with a vanity sink. Other domestic hot water (DHW) uses include two shower rooms, one bathtub, two utility closets, four nurses' stations and a kitchen.

The system has four 100-foot copper earth loops installed vertically at a depth of 100 feet. The facility's DHW source consists of two 15 KW, 480 v electric water heaters operating in parallel. Each water heater has two electric elements controlled by a single aquastat. One element port in each heater was removed and is used for the heater water return from the EarthLinked geothermal unit. As hot water is used at the site, cold city water enters the tanks.

"The EarthLinked system works most efficiently when heating cold incoming water," said Hal Roberts, CEO of Lakeland, FL-based ECR Technologies, the nation's leading developer of direct-exchange geothermal technology. "For this installation - which also used a hot water recirculation pump to assure immediate access to hot water at any point of use within the DHW system - the average return temperature to the heat pump was 94°F."

"The geothermal heat pump installed to do the job was actually over-sized," added Adamson. "Had that not been the case, total energy savings would have been substantially higher. In other words, if there had been a larger thermal load - a bigger facility or one with 24-hour hot water demand - the system would have performed at optimum efficiency."

The water heating systems, which require little space inside a building, are ideally suited for apartment or condo complexes, motels, colleges and universities, restaurants, health care facilities, food processing operations and a variety of other commercial users.

The EarthLinked water heating system offers the highest efficiency of any powered water heating system. "The technology has proven itself over twenty-five years of operation," said Roberts. "What's new is the way the geothermal heat pump system is coupled to traditional commercial water heaters and works in tandem to increase efficiency, capacity and reliability to meet high-volume water heating needs."

The most economic water heating application for these systems is to heat or preheat domestic water for large commercial users. The geothermal system can heat the water up to 120°F. It is then stored in, and may be "topped off" by traditional gas or electric water heaters, increasing the heat to any desired higher temperature.

"The systems do not consume energy to create heat," added Roberts. "They extract renewable energy from the earth and thereby reduce the burning of fossil fuels that release greenhouse gases to the atmosphere. They deliver up to four units of heat for each unit of electricity used to operate the heat pump. That's 400% efficiency, while the most efficient traditional water heaters do not achieve 100% efficiency."

The Environmental Technology Verification report by the EPA also confirmed that each EarthLinked heat pump water heating system can avoid the emission of up to 7,000 pounds of carbon dioxide per year for each ton (12,000 BTUs) of compressor capacity. That eliminates up to 42,000 pounds of carbon a year for a 6-ton unit.

The manufacturer uses standard heat pump components and its own patented refrigerant flow controls. The system is connected to refrigeration grade tubing that is placed in direct contact with the renewable heat source in the upper 100 feet of the earth's surface. The ground temperature is stable year round, and in the U.S., ranges from 42 degrees at the Canadian border to 78 degrees in the southern extreme.

Early versions of the EarthLinked system were used to heat water beginning in 1983 in the smaller quantities needed for single family residences. It was the most efficient system tested by the Florida Solar Energy Center when the electric back-up energy used by solar thermal systems was taken into account. Water heating has always been an optional feature of the EarthLinked space heating and cooling product, which is operating in 41 states and 14 countries.

The cost of installing the refrigerant evaporating loop in the earth is a substantial part of the system's price. The excavation cost varies with the installation method, which can use small bore drilling, directional boring, trenching or excavation to install the refrigerant lines vertically, diagonally or horizontally, even under a parking lot. But the cost can usually be recovered within 24 to 36 months, depending on usage and energy costs. Escalating energy costs may further reduce the payback period and increase ROI.

Because of high efficiency thermal exchange with its heat source in the earth, only 100 feet of earth loop per ton of heat pump capacity is needed, and a three inch diameter bore hole is optimal. This allows the system to be easily adapted to new construction or retrofit applications.

"Economically, these systems make great sense for high volume hot water users," states Roberts. "And even though the installed cost of an EarthLinked system is greater than that of a traditional water heater, the monthly energy savings for a commercial application are so significant that the system quickly pays for itself."

A commercial user installing an EarthLinked system at a cost of $17,000, using 2,000 gallons of hot water per day, with an electric rate of $0.10/kWh, an earth temperature of 65°F, using the EarthLinked system to raise the water temperature to 115°F, and the electric resistance element to raise it an additional 10° to 125°F, saves up to $7,169 annually when compared to an electric water heater. The cost recovery period in that case is 2.5 years, which yields an ROI of 40.01 % annually.

"A payback within thirty months is an opportunity for savings that is hard to pass up. Both of our customers who hosted the testing ordered additional units when they saw the results of the monitoring programs," added Roberts.

The Greenhouse Gas Technology Center is operated by EPA and the Southern Research Institute. It conducts independent performance verification testing of energy efficiency and greenhouse gas emission reducing technologies. The full report may be found at www.EarthLinked.com. For further information, call Joe Parsons of ECR at 863-701-0096.