By Des Keller
Progressive Farmer Contributor
Jim Sladek has to pause for a moment when asked if he would do anything different in the construction of the farm shop/farm office he's used for more than three years. Then, he shakes his head "no."
"Quite a bit of thought went into the shop, and so far, we're happy with how it turned out," says Sladek, managing partner of JCS Family Farms, near Iowa City, Iowa. "We went around and stole ideas from everyone else, things we liked."
Two of those ideas that have really paid off include building the shop with structural insulated panels (SIPs) and using a geothermal system to heat and cool the shop and offices. The 80- by 120-foot shop, with 20-foot-high ceilings, along with a 3,500-square-foot farm office, costs an average of about $400 per month, year-round, to heat and cool.
"It's pretty amazing," Sladek says. "I kept track of our electrical expenses for the first 12 months. And that's with the shop at 72 degrees Fahrenheit in the summer."
That's the power of using a building system that is up to 15 times more airtight than conventional construction and can reduce energy costs up to 50%. The closed-cell foam walls can also stop the transfer of moisture that can increase rust and corrosion.
WALLS IN A PANEL
SIPs are engineered and manufactured by Iowa-based Energy Panel Structures. Custom Builders, of Tipton, Iowa, were the contractors hired to construct the buildings. The SIPs essentially consist of two sheets of 3/4-inch plywood bonded to, and sandwiching, 7 1/2 inches of rigid foam plastic insulation.
Once on site, the 4- x 4-foot panels are locked together "kind of like puzzle pieces," Sladek says. "The engineering to our site and our specifications took place before the panels arrived here," he adds. "It only took a couple of days for the building to be constructed."
The shop walls have an R-value of 33, while the blown-on fiberglass ceiling insulation has an R-value of 40. The SIPs are covered on the interior with white fiberglass-reinforced plastic panels known as glass board. The covering is smooth and nonporous, and has no exposed fasteners, which makes it very easy to clean.
The shop's floors consist of packed gravel and high-density foam insulation beneath 9 inches of poured concrete laced with rebar. Geothermal "radiant" tubes carry a mixture of water and propylene glycol.
"It is important to insulate underneath geothermal lines," Sladek explains. The radiant tubes under the floor are part of a system in which 36 additional lines travel out 200 feet away from the shop buried 16 feet underground. At that depth, temperatures remain between 52 and 55 degrees Fahrenheit year-round.
Essentially, a geothermal system exchanges heat with the earth rather than the outdoor air to regulate temperatures indoors. "A geothermal heat pump doesn't use combustion, it collects heat and moves it," says Jake Rabe, of Rabe Hardware, Blairstown, Iowa, the largest geothermal contractor in the state.
In winter, the fluid in the lines absorbs heat from the ground and carries it indoors, where it is compressed to even higher temperatures before being distributed through the radiant tubes. In summer, the system pulls heat from the building into the ground via those same buried lines.
A geothermal system has three main components:
-- A liquid heat-exchange medium. This is the water-glycol mix that runs either horizontally or vertically underground.
-- A heat pump unit. The Sladek system actually uses six heat pumps for efficiency—five for the shop and one for the office. A computer controls the heat pumps, depending on the need in the buildings.
-- Air delivery and radiant heating. The Sladeks use both an air-delivery system and in-floor radiant heating. The shop is warmed by the radiant-heat system in the floor. A forced-air unit heats and cools the farm office through runs of ductwork.
In considering the decision to use a geothermal system, Sladek found there were no in-between opinions. "Folks either really loved the geothermal, or they hated it," he says. "What we found was that those that didn't like it were working with systems that weren't sized correctly to their particular structure."
Jake Rabe agrees, adding that farms are ideal locations for the use of geothermal. "They have three things that help with justifying geothermal," he says. "They have land, which makes it easier to run the lines, and they are well aware of their propane costs."
The Sladeks also benefited from a federal tax credit to install the fuel-saving geothermal system, and they qualified for a USDA Rural Energy for America Program (REAP) grant. This program provides guaranteed loan financing and grants for the purchase of renewable energy systems. Applications for REAP loans and grants are no longer being accepted this year.
Benefits from this program can be used for energy systems that use biomass or wind power, in addition to geothermal. Additionally, the Business Energy Investment Tax Credit equals 10% of the total expenditures with no maximum credit limit. This credit covers geothermal systems put into service after Oct. 3, 2008, and before Dec. 31, 2016.
As a result of this assistance, Sladek says the payback on their geothermal system is about two years -- and would have been less than 10 years regardless. "It is really a no-brainer," he says.
A GREAT PLACE TO WORK
JCS Family Farms tried to use the best design features it could so this shop would serve as the farm's hub for the next couple of decades. Here are some of the highlights.
-- Service Pit. An 8-foot-deep service bay gives employees plenty of room to work beneath machinery. The space is equipped with recessed lighting and shelves, as well as a toolbox. A bumper several inches high runs around the opening of the pit on the shop floor to prevent forklifts or other vehicles from tipping into the hole. Sturdy mesh netting covers the opening to prevent workers from accidentally falling into the hole when it isn't in use. As soon as the lights in the bay are turned on, ventilation fans kick on to make sure the air down in it remains refreshed.
-- Drains Inside And Out. Not only are drains inside the shop, but the Sladeks also had drains installed in the concrete apron around the exterior of the building. When schedules are busy -- particularly in the spring and fall -- machinery work is as likely to take place on the apron as inside the building.
-- Oil Separator. The drains lead to an oil separator, which filters out waste oil for proper disposal.
-- Under The Floor. There is a distinct lack of clutter on the walls of the shop at JCS Family Farms. Careful advanced planning allowed the farm to run electrical wiring, water lines and other utilities under the floor and up into the walls.
-- More Light, More Work Space. A considerable amount of machinery work can take place on the apron around the building. Lights installed onto the doors provide illumination above the apron when the doors are open. "They allow us to have even more good work space," says Jim Sladek, JCS Family Farms.
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