Fishing For Energy-Efficient Heating

A Weil-McLain boiler system works for an aquaponics farm.

Shifting a career focus from soybeans and corn to tilapia and lettuce, the Goodenough family was in unchartered waters as they began a new venture into aquaponics farming. An advanced building-control system using Weil-McLain, Burr Ridge, IL, Evergreen boilers helped ensure smooth sailing for the first growing season.

The Goodenough’s are a fourth and fifth generation farm family in Mindoro, WI, located on the west side of the state. The farm began with raising hogs and cows, then later moved to a corn and soybean operation, and now is an aquaponics grower. The catalyst for the move to aquaponics occurred several years ago when, according to Tim Goodenough, “input prices were high, grain prices were fluctuating constantly, and Mother Nature was throwing us curve balls.”

As a result, Tim started researching different agricultural methods. He had fish farming in the back of his mind after seeing an operation on an American Soybean Association trip to South America several years earlier. “When I came back home I had a lot of information about fish farming ,and we began looking into the concept,” said Tim, who was raised on the farm and runs it with his wife, Bonny, and their four children. The family’s research led them to consider aquaponics.

Aquaponics combines aquaculture, or fish farming, and hydroponics (raising plants without soil), in a closed-loop system. The nutrient-rich water that results from raising fish provides a source of natural fertilizer for the growing plants.

Ready to give the aquaponics operation a go, Tim and Bonny purchased a used four-section, 13,600-sq.-ft. greenhouse. The family spent three months physically disassembling and dismantling it before transporting the greenhouse piece by piece to their farm. The next year, the family finalized construction plans for the greenhouse and the attached lean-to building that would house the mechanical systems. Concrete piers were poured and support posts and trusses were set.

The re-construction of the greenhouse began in 2016. The Goodenough’s worked in tandem with a construction crew for six months until the facility was completed. They also hired Ron Hammes Refrigeration, a residential and commercial HVAC company based in La Crosse, WI, to handle installation of the heating equipment and piping.

An advanced building-control system uses Evergreen boilers to regulate the growing season for an aquaponics farm.

Testing the Waters

With the greenhouse ready for operation in November, and the wintry Wisconsin weather setting in, the heating system needed fast installation.

“We require air temperatures of about 70 degrees in the greenhouse year-round and water temperatures between 70 to 75 degrees for the fish and plants to thrive,” said Bonny.

Another important concern was the greenhouse structure, which consisted of lightweight polycarbonate, could collapse under the weight of a heavy snowfall.

“Snow could wreak havoc on our structure and so it was imperative to get the heating system online as soon as possible,” Tim added.

To meet project parameters, James Hammes, president of Ron Hammes Refrigeration, recommended installing four 399 MBH Weil-McLain Evergreen boilers with primary-secondary pumping in a multiple boiler system (MBS). In this configuration, a master boiler controls the modulation and sequencing of boilers on the network to achieve the desired system supply temperature.

“With the automatic sequencing feature, the boilers communicate directly with one another so they sequence themselves and rotate as needed,” explained Hammes. “They operate to optimize energy use and efficiencies. When heat is required, the boilers will stage on one-by-one as needed.”

The Evergreen units were tied to existing heat exchangers on site and installed as part of a Wadsworth system, a building-control solution that monitors external temperature, wind speed and direction, precipitation and humidity, and also internal factors such as temperature and humidity. To maintain conditions, the advanced Wadsworth system cycles the boilers, heat exchangers, and grow lights on and off, and opens and closes vents and shade cloth based on the amount of sunlight. It is designed to keep humidity and temperature levels inside the grow operation at targeted parameters.

“We are essentially trying to create the longest summer day of the season year round in the greenhouse,” explained Tim. “The vents, lights, and shade cloth are all computerized and move automatically to maintain conditions.”

With the heating system in place, the nursery was filled in early December with 130 tilapia and several varieties of vegetables. When all fish tanks are filled, they hold approximately 2,300 fish.

A master boiler controls the modulation and sequencing of boilers on the network to achieve the desired system supply temperature.

Results Hold Water

According to Tim, the installation of the boilers went smoothly, and the family’s Floating Gardens LLC aquaponics farm operation is already a success. The four Evergreen boilers maintain proper temperatures in the building, while providing supplemental heat for the fish tanks and nurseries.

“The boilers are very energy efficient and will cycle on and off as needed,” said Tim. “They typically shut off when the temperature outside is 65 degrees and above.”

Alleviating a major concern, the boilers also allowed the greenhouse to stay snow free all winter. “We had some major snowfalls this last season, but it always melted and never accumulated on the roof of the greenhouse,” Tim reported.

Today, the Goodenoughs are producing approximately 250 heads of lettuce a day with varieties of romaine, butterhead, and summer crisp. The family also is growing other produce such as Swiss chard, peapods, string beans, kale, tomatoes, and radishes.

“We harvested our first gourmet lettuce crop in April, and we will begin selling freshly harvested tilapia mid-year, when the fish have reached market weight of about 11/2 pounds,” said Bonny.

The Goodenoughs sell their products at their on-site market, and to farmers markets, local restaurants, schools, and grocery stores.

“We believe aquaponics is the new face of farming as it is sustainable, healthier, and can supply more food per acre than traditional methods,” said Tim. “We are very happy with the system we have in place, and the Weil-McLain boilers are a key component in making this efficient growing method a success.”

— Learn about Evergreen boilers.

— See the farm in operation.

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