ACHRNEWS

Chiller System Solves Challenge Posed by Log Cabin

May 7, 2012
Log Cabin 1
Some HVAC contractors like a challenge. Their expertise and design knowledge are often what set them apart from their competition. Pond’s Plumbing & Heating of Salt Lake City, Utah, took on the challenge of designing and installing an HVAC system in a 20,000-square-foot log cabin home, nestled in the Teton Valley of Northeastern Idaho.

The first challenge: The homeowners wanted to maintain the integrity of the exposed wood of the home and did not want any visible signs of ducting or outlets on the interior; and no mechanical “boxes” around the exterior.

Working with distributor US Air Conditioning of Salt Lake City and manufacturer Unico Inc., Pond’s was able to collaborate on a system design that ultimately proved to be energy efficient and comfortable — with a minimal carbon footprint.

“The structure, while new construction, was designed with very little space for ductwork,” said Brian Intagliata, marketing associate for Unico Inc. “Even with our small ducting, the installation and the design was a challenge. Pond’s was very experienced in plumbing, and we gave them a great deal of support, both in the design phase and in the installation and post-installation phase of the installation.”

According to Unico, the system necessary for this log cabin home required Unico small and flexible duct, which is one-fourth the size of most HVAC ductwork. Its size enabled ducts to fit into hollowed-out beams and other tight places, remaining hidden from view.

“The outlets are customizable circular or flat pieces that come in varying materials or wood finishes,” Intagliata said. “The outlets were stained to match the wood from the logs and were hidden in inconspicuous areas.”

By nature, log homes are very difficult for HVAC design and installation. “Because emphasis in log homes is placed on the aesthetic of exposed wood, installing outlets and ductwork can be especially difficult while maintaining the integrity of the design,” added Intagliata.

Maintaining the unique exterior features of the home was equally important to the homeowners. In order to hide the UniChiller outdoor unit, Pond’s located it 275 feet away from the house in a remote area and enclosed it in a custom-built housing unit. The piping from the unit to the indoor air handlers runs underground.

Designing a system that was basically invisible was only one challenge. Another was the sheer size of the home and its varying cooling loads throughout the day. That’s another reason why Pond’s recommended the UniChiller.

“The UniChiller has the capability to establish zoned cooling areas,” Intagliata said. “It generates chilled or heated water only to the extent of satisfying the zones of comfort calling for either heating or cooling.

“It is a reverse cycle, completely self-contained outdoor chiller and uses water to heat and cool as opposed to refrigerant and connects seamlessly to an indoor air handler. Using water makes the system environmentally friendly because there is no risk of a refrigerant leak and it is more energy efficient.”

Yet another challenge was the home’s location. “We had to design the entire structure for a high altitude,” said Intagliata. “When you take into consideration that we had a water-based system for cooling, we had to assess the effect of both altitude and a 40 percent glycol mix for the application and back this into Btus needed.”

The entire system is comprised of 11 Unico complete duct systems with chilled water and hot water coils. “The entire home is heated with radiant floor heating and each of the Unico systems have both air filtration and humidification on them,” said Intagliata.

It took a combined 150 hours collaborating on the system design, and according to Intagliata, “The customer is very pleased.”

And after all, a happy customer is usually a customer for life, which in this case, made the design challenges even more rewarding.

Publication date: 5/7/2012