The high cost of heating water in hotels, restaurants, health care facilities and other big users may now be cut drastically with a geothermal heat pump.

COMMERCIAL HOT WATER SYSTEMS

Hal Roberts

EarthToys Renewable Energy Article
The high cost of heating water in hotels, restaurants, health care
facilities and other big users may now be cut drastically with a geothermal
heat pump.

Hal Roberts of ETI


The Green Way to Slash Commercial Hot Water Costs

Few businesses are aware of how much it costs to heat water. It’s rolled into their electric or gas bills. But it can be a lot -- up to 40% of energy costs for some businesses.

That chunk of “fixed” energy expense may now be cut drastically with a geothermal heat pump.

“My operations people ‘ohooed’ and ‘ahhhed’ when they saw how dramatically it reduced our electric costs,” says David Vaughan, CEO of Senior Care Group, Inc., after having the EarthLinked Technologies Inc. (ETI) commercial hot water system installed in a central Florida nursing home managed by his company. If he had his way, he would retrofit all of his company’s 20 nursing homes with the system.

After one year of monitoring its performance in the Senior Care Group home, the U.S. EPA verified that the EarthLinked system consumed 75% less electric energy than a comparable electric-resistance hot water system. The EarthLinked system also achieved a “dramatic” 400% electrical efficiency, according to the director of the agency’s Greenhouse Gas Center.

For a 6-ton-capacity system (72,000 BTUs), large enough to deliver more than 2,000 gallons of hot water a day, that efficiency translates into saving 42,000 lbs of CO2 and 300 pounds of NOx emissions annually.

Radically better
Water heating technology has changed little in the past 100 years; 94% of buildings depend on either electric-resistive heating elements or on-site fossil fuel combustion.
Despite efficiency-enhancing improvements -- increased tank insulation, gas igniters, condensing boilers that capture residual heat from flue gases, tankless (point-of-use) heaters -- no traditional systems can achieve even 100% efficiency.

“The basic premise has remained constant – all traditional systems use more energy than they deliver,” notes Hal Roberts, co-founder of Lakeland, Florida-based EarthLinked. “What EarthLinked offers is radically different – and better.”

It also is more sensible than other renewable energy technologies for heating water.
Waste-heat recovery units are great, but can only be used where there is an adequate, continuous and nearby source of waste heat, such as air conditioning or other refrigeration systems.

Solar hot water heaters remain dependent on steady sun, large solar collector surfaces,  back-up heat sources and, to achieve an acceptable payback period, financial incentives.  Wind turbines, like solar, require a large visual imprint and are dependent on the vagaries of weather.

Geothermal heat pumps are noted by both the EPA and DOE as the most reliable and environmentally clean method for heating and cooling space. They carry the same benefits for heating water. However some geothermal heat pump systems are more efficient, and therefore offer a quicker payback, than others.

Direct Exchange
Almost half of the sun’s thermal energy that reaches the earth is absorbed by its upper crust. Its huge thermal mass is a stable heat reservoir. Fifteen to twenty feet underground, temperatures range from about 42° F on the U.S./Canadian border, even in the dead of winter, to 78° F in southern Florida. Those ground temperatures vary little, providing a dependable heat source, 24/7, in all seasons and anywhere on earth.

For instance, 1400 miles north of Vaughan’s central Florida nursing home, David and Lynn Thomas retrofitted their 144-unit apartment complex in Claremont, NH, with an EarthLinked commercial hot water system, and, despite frigid winters and rate increases, watched their annual electric water heating bills drop from $60,000 a year to closer to $30,000.

Geothermal heat pump systems extract that thermal energy and, using the heat pump circuit, compress and deliver it to heat buildings or water. In summer, they extract heat from the building and store it in the ground.

Some geothermal heat pump systems are water-based, involving multiple heat transfers. A water/antifreeze solution is pumped through a large underground network of plastic tubing. The geo-heat collected is transferred through an intermediate heat exchanger into the heat pump circuit, then to a refrigerant circuit that is used to heat the water tank. These three heat exchanges limit electricity efficiency to a ratio of 2.5/1 or 250%.

That’s excellent efficiency if compared with fossil-fueled systems, but generally not good enough to recover in less than five years the cost of installing the ground loop. In fact, no water-based geothermal heat pump systems are currently marketed in the U.S. for commercial water heating use.

The EarthLinked® system involves direct exchange, limiting the number of thermal transfers which makes it a \more efficient, reliable and simpler system. 
Six to eight closed loops of highly conductive copper are placed in 3-inch diameter bore holes in the ground. They are shorter, smaller and better heat harvesters than the heat exchangers of other systems. They can be installed vertically, horizontally, or diagonally, making retrofits in existing buildings possible. In fact, a 6-foot-by-6-foot surface area is usually enough room for inserting the heat exchange system.
A non-ozone depleting refrigerant (R-407C) runs through the copper tubing. The loop passes through a heat pump compressor, a double wall heat exchanger that directly transfers the heat to the water tanks.

The EarthLinked heat pump is small, fully enclosed, quiet and hidden from view in the building’s mechanical room next to the water tanks.

Best for Big Users
The EarthLinked system can heat water to 115°F. If hotter water is needed, the heating component of any standard water heater tank can boost the temperature.
Keeping intact a building’s traditional water heating unit, EarthLinked can be connected in the water supply line next to the tank. In that application, it pre-heats the water to a set point and leaves the control of the ultimate distribution temperature up to the storage water heater tank.

The hybrid system increases capacity and offers the reliability of redundancy. The EarthLinked unit delivers most of the required BTUs, with the gas or electric heater only topping-off and maintaining the desired temperature. This reduces the installed cost and provides energy savings in excess of 50%. If the EarthLinked system is used as the sole source of heat, savings up to 75% can be achieved, but at a higher initial cost because of the need to install more earth loops.

While the price of geothermal heat pump equipment is competitive with that of other heating systems, the installation cost usually is significantly higher and varies depending on location and available drilling expertise.

Even so, the system usually pays for itself within 2 to 4 years and has a typical ROI of 35-50%. That compares with 7-to-10 year payback and a ROI of 10-15%  for solar-heated hot water systems.

The most economic application of the EarthLinked system is for large (2,000+ gal/day) users, such as lodging, healthcare, apartments, dormitories and food preparation and service.

Around the World
Geothermal heat pump systems are quietly heating and cooling more than 2 million businesses, homes, schools and military bases around the world. EarthLinked systems were developed in 1980 and now boast more then 100 million hours of energy and environmental savings in 47 states and 15 countries, from Australia to Alaska.

The geothermal heat pump industry has shown a steady 20% annual growth in recent years in the U.S. and greater growth in Canada, Europe and parts of Asia. Even so, it lags behind other renewable energies in public understanding and government support. Roberts believes that’s about to change.

“EarthLinked is a simple technology, but it’s less understood than solar or wind power because there are no visual reminders of its existence after it is installed.” notes Roberts. “Some people confuse it with high-temperature, deep-earth geothermal, but we do not have to drill deep for the solar energy that is stored in the shallow earth.”

With a new administration promising to support renewable energy; a new $2,000 federal tax credit for on-site geothermal heat pumps; other incentives in the works, including from electric power companies; a desire among businesses to both save money and be green; and a scramble among states to cut CO2 emissions, Roberts sees geoexchange poised to break into the broader public awareness as an excellent way to heat space and to heat water.

 

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