DOA System Suits Animal Shelter
In 2009, the Humane Society of North Central Iowa was in dire need of a new shelter to service a seven-county area. Its old facility consisted of two buildings with a combined size of 2,500 square feet and an annual energy bill of $25,000. Thanks to donations and fundraising efforts, the society was in a position to commission a new 10,000-square-foot facility with 32 indoor/outdoor kennels, offices, a veterinarian room, a training room, and a community center. Architectural plans were drawn up to improve air quality for employees and pets, remove humidity from kennel areas, separate kennel air from the community area, prevent odor infiltration, and provide superior energy savings.
Although the project had to be redesigned more than once, the Almost Home Animal Shelter in Fort Dodge, Iowa, has now been efficiently operating for more than a year with a dedicated outdoor air system (DOAS) and an integral energy recovery wheel.
To be environmentally conscious, the shelter’s board initially requested a geothermal heating and cooling system be part of the plan. But the initial bids received by the Almost Home building committee exceeded the budget by $1 million. At this point, the building committee decided to work directly on a design/build basis to bring the costs in line.
Jensen Builders of Fort Dodge worked with Mike Kopp of Kopp Mechanical, an HVAC design consultant, to design a more traditional system that would provide the necessary air changes for the kennel portion of the shelter. This design included two 100 percent make-up air units with DX cooling and 13 exhaust fans required for zone ventilation. According to Kopp, this plan was based on “a 100 percent occupancy issue and a 24-hour need.”
HVAC contractors were asked to bid, and Mid State Plumbing and Heating of Fort Dodge came in with the low bid. While this version of the design resulted in substantial savings over the geothermal system, the energy costs were estimated to be in the $40,000 to $50,000 range due to the need to constantly bring in 100 percent outside air.
That was unacceptable for building committee chairman Larry Clement, and he was the catalyst behind the next design change. Clement is the owner of a local truck dealership, and due to a previous business relationship, he was familiar with Greenheck, a manufacturer of air movement and control equipment. He called attention to the performance features and the potential energy-saving benefits of Greenheck’s energy recovery ventilators with heating and cooling, which are also referred to as a dedicated outdoor air system with energy recovery wheel.
Kopp and Don Livasy, owner of Mid State Plumbing and Heating, were also familiar with Greenheck products and worked together on the redesign and installation of the system that ultimately included two dedicated outdoor air units and five ceiling exhaust fans.
“With the new system design, there was a reduction of eight of the previous 13 zone exhaust systems,” Kopp said.
At the Almost Home Shelter, the dedicated outdoor air systems employ total enthalpy energy recovery wheels, modulating supply and exhaust fans, and CO2-based demand control systems for optimum energy efficiency. The enthalpy wheel enables the system to recover up to 80 percent of the heating and cooling energy contained in the exhaust air and also removes humidity from the outside air in the summer prior to passing through the cooling coil, therefore reducing the tonnage necessary for cooling. Factory-mounted variable-frequency drives modulated by CO2 levels further enhanced the unit’s efficiency by only delivering the required amount of outdoor air to the space.
Kopp was very positive about the application of an energy recovery wheel for an animal shelter. “The original make-up air unit design for the animal areas exhausted 100 percent of the air. The redesigned system captured 87 percent of the exhaust air,” he said.
“In the summer, the energy recovery wheel reduces the entering make-up air temperature and humidity, reducing the load requirement before being conditioned. The same benefit is achieved in the winter by preheating the incoming make-up air through the energy recovery wheel, therefore reducing heating capacity requirements.”
Ceiling exhaust fans and an inline cabinet fan were installed to not only provide the necessary air changes but also to remove excess moisture from the kennel area following regular automated washdowns. This ensures fresh, comfortable, odorless air for the workers and visitors to the shelter.
When asked about the possibility of other contractors in other markets using DOAS with energy recovery for kennels or animal shelters, Livasy said, “I think it would be a perfect fit. With a lot of animals, you need a lot of air changes. And with energy recovery, you can reclaim the energy that is contained in the airstream.”
The installed mechanical system also included an Amana 92 AFUE furnace and 7-ton, 14-SEER condensing unit for the office areas and a Trane PTAC unit for the community room for supplemental heating and cooling. The animal visitors were also comfortable in the winter because of a radiant heating system installed throughout the kennel area consisting of a Triangle Tube Prestige Solo condensing boiler and an Uponor in-floor polyethylene (PEX-a) tubing system.
Payback in a Year
The Almost Home Animal Shelter went through several design/build changes and involved the time and dedication of several local professionals and a dedicated volunteer before it was completed. Yet all the teamwork and effort has paid off in energy savings and comfort.
Clement couldn’t be more pleased with the end result after the shelter had over a year of operation under its belt. “It exceeded our expectations, and our expectations were high,” he said.
After the first year, the energy costs for the 10,000-square-foot facility were only $16,600, compared to the $25,000 annual bill for the old buildings.
Clement added, “We couldn’t be happier with the quiet operation and the quality of indoor air. You don’t hear the fans running at all. And with the 12-15 air changes per hour in the office area, there are absolutely no odors in the office or community center area and very little in the kennel area.”
Publication date: 04/16/2012