UA Professor Researches Lake Source Heat Pumps

TUSCALOOSA, Ala.–How do you handle the Alabama summer heat? Some residents of the Lake Tuscaloosa area have discovered an atypical way to stay cool during the summer, while saving money in the process.

About 10 residences surrounding Lake Tuscaloosa use lake source heat pumps for cooling, said Dr. Steve Kavanaugh, professor of mechanical engineering at The University of Alabama, who researches the energy efficient cooling method. It’s what those residents do not say about their chosen method of cooling that indicates their satisfaction, he says.

“They’ll call to ask questions at first and then I never hear from them again,” Kavanaugh said.

The UA engineer strives to improve design tools for developing the systems and to ensure they have low environmental impact. In the lab, Kavanaugh used a 52-inch-tall pool, 15 feet in diameter, to simulate a lake. He also incorporated measured water temperatures at Lake Tuscaloosa in the research efforts.

In a lake source heat pump system, coiled piping rests in the water and connects to a box system located inside the owner’s house. The lake piping coil contains water and a small amount of propylene glycol, a biodegradable substance found in many food products. One reason heat pumps are more appealing to some than a typical heating and cooling system is because the system’s box is smaller and all the components are indoors, increasing durability.

While lake source pumps have been in use for about 15 years, Kavanaugh says little research has been done on them, and there are few accepted design procedures. The UA engineer says a homeowner could save as much as 70 percent on their heating/cooling bill, depending on the lake providing the energy.

“The heat pumps are much more efficient, use much less electricity and reduce pollutants that contribute to runoff,” Kavanaugh explained. “Each lake is different, and weather becomes a factor too.”

The heat pumps are not a significant source of heat or pollution compared to some boats that utilize up to 200 horsepower, Kavanaugh explained. The amount of heat put into the lake from a typical unit is less than a 20 horsepower motor. Additionally, most of this heat will be removed by the system in the winter.

Kavanaugh work, focusing on temperature ranges and environmental impact of these systems, has recently published in the leading journal for heating and cooling engineers.

Kavanaugh hopes to make his findings available to the public so that environmental regulations can be based on sound research rather than uninformed opinions. The findings of the research will also emphasize the establishment of limits for how many units can be put on a lake to ensure that the environmental impact is minimized, Kavanaugh said.

Kavanaugh is a leading national expert on heating and cooling systems, specifically geothermal heat pumps. He has developed widely used design procedures related to these types of heat pumps, and he was recognized for his contributions to society by the American Society of Heating and Refrigeration Engineers as a Fellow in 2003. Kavanaugh is also a user of this technology in his former home in the Druid Hills neighborhood and in his new home on Lake Tuscaloosa.

In 1837, The University of Alabama became the first university in the state to offer engineering classes and was one of the first five in the nation to do so. Today, the College of Engineering has about 1,800 students and more than 95 faculty. It has been fully accredited since accreditation standards were implemented in the 1930s.

Note to Editors: For further interviews and testimonials of consumers currently using this technology on Lake Tuscaloosa, contact Mary Wymer at 205/348-6444.