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Earth Energy N.H. retirement facility goes Geo Geothermal think tank takes on extraordinary job
BOSCAWEN, N.H. — As a hedge against the certainty of increasing en- ergy rates, six years ago managers of Merrimack County Nursing Home (MCNH) here invested deeply in ge- othermal technology. Today, they and hundreds of residents there celebrate substantial savings and new levels of comfort and air quality. Geothermal energy has given new life to this re- tirement community. It was back in 2005 when Hamp-
stead, N.H.-based Water Energy Dis- tributors Inc. was hired as a subcontractor by the engineering firm, McFarland-Johnson, to design an all-geothermal mechanical system for MCNH. Work on the system – in- stalled in several stages as the facility went through various construction phases – was just completed. The 235,000-square-foot facility
has a staff of 425, and 290 beds with luxury accommodations for elderly residents. Merrimack’s über-green mechanical system incorporates 16 standing column wells and 326 Cli- mateMaster water-to-air heat pumps for a total of 615 tons of capacity.
Looking back Success of the facility’s job ties to
early development of an energy-tap- ping technique developed by the founder of Water Energy Distributors. Carl Orio spearheaded development of the standing-column geo-exchange well almost 35 years ago. Today the company he founded in 1981 is recog- nized as a global leader in geothermal design and distribution. The standing column well is now re-
garded as offering one the highest effi- ciencies of any geo-exchange system. Three years after Carl Orio incor-
A technician from Merrimack County Facility Maintenance conducts a diagnostics check on the geo-exchange system at the Merrimack County Nursing Home.
firm. All along, the focus has been the sale and design of sustainable, renew- able energy systems. So, as one generation encourages involvement of the next, mechanical challenges like this one benefit from decades-old vision and expertise, and the latest technology.
No job too big
“At MCNH, the first order of busi- ness was to closely study the area’s
Tips from Carl Orio for designing and installing a commercial standing column geothermal system
• All the deep well drillers in the
Northeast have a second compressor on a trailer to back up the compressor on the drill rig. The truck-mounted compressor is sufficient to a depth of about 800 feet. Any deeper and one compressor just can’t keep pace with high-yield wells. • The handling of VFD systems
can be tricky. Run lines for VFDs sep- arately. Even though you may have numerous VFD lines side-by-side, they all have to be in separate con- duit piping. All VFD manufacturers re- quire shielded wire, and some even require running the lines through steel conduit. • Electronically speaking, VFDs
create a very ‘dirty’ electronic signal. VFDs are actually capable of emitting signals in the AM radio range. You can drive through town with your car’s radio set on a weak AM frequency, and hear which house has an exer- cise bike or Stairmaster with a VFD. If the lines are run together, they can in- terfere with each other’s signal. • Over the years we’ve learned that
when designing a geothermal system over 10 stories high, it’s economically viable use a primary and secondary well loop with an intermediate heat exchanger, instead of pumping well water all the way to the top. Some ef- ficiency is lost with the intermediate heat exchanger, but somewhere be-
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wells within the identified area as being most suitable for geo-ex- change,” said Fred Mock, vice presi- dent of Binghamton, N.Y.-based McFarland-Johnson. “Based on the heat load, we recom- mended 16, 10-8-6 wells, each 1,500 feet deep,” said Orio. The term “10- 8-6” stands for a 10" casing sealed into the bedrock, an 8" rock bore, and a 6" sleeve and pump. Each sub- mersible pump has a 10-hp motor to
tween eight and 12 floors, that effi- ciency loss is justified by the money saved in system water pumping. • The 10-8-6 standing column well
is, for the most part, a special pur- pose well. Because of the higher in- stallation cost, industrial systems that incorporate standing column wells generally utilize 8-6-4 wells, and res- idential systems always do. The 10-8-6 shines when ground
space is limited. Various systems in New York City and several systems in Connecticut have used this BTU mon- ster. Using the larger well cuts down on the number of wells needed. At MCNH, it would have taken five addi- tional wells if 8-6-4’s had been used. Not only would this have been too many wells to fit in the available green spaces of the parking lot, but would have also required a third manifold.
the nursing home’s parking lot. Split up into two well fields, eight wells are located under the upper parking lot, and eight below the lower, with the farthest well being 850 feet from point of entry into the building. Each eight-well field is piped to its own supply and return manifold. The caps are protected by manhole covers, and can be found in the green spaces be- tween parking areas. Amherst, N.H.- based Skillings and Sons was the driller contracted for the MCNH job. The company had two of their four drilling rigs on the job, operated by five employees. “Each well took us about six days
to drill,” said president Roger Skillings. Drilling an 8-inch hole through 1500 feet of solid granite is no small task; it was a blessing in dis- guise, though. According to Skillings, the number-one enemy of a healthy standing column well is soft rock that cracks, collapses and caves in. “The first thing we do at any job
that is to include a standing column well, is to drill a test well,” explained Skillings. “If the rock hardness, den- sity, and the quality of the water are all desirable, that test well becomes the first well on the field. At this site, we found some of the best, mineral- (Turn to Geothermal... page 26.)
porated Water Energy Systems, he brought his daughter Christina into the business as general manager. In 2000, she became president of the
hydrogeology to determine the best location for the well field. Water En- ergy was instrumental in determining optimal well spacing and number of
push water to the building’s mechan- ical room, and from there to all the heat pumps within the system. All 16 wells are located beneath
•THE WHOLESALER® —MAY 2011
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