Project Aims to Set New Standards for Junction Boxes
A properly sized and efficiently functioning residential HVAC system starts with the ACCA manuals and the guidelines they offer for heating and cooling load calculations, duct design, and equipment selection.
But in working with production homebuilders, IBACOS has seen poor air distribution and comfort-related issues in flex duct HVAC systems that use a type of equipment for which ACCA Manual D provides few guide
lines: ductboard distribution boxes, also known as junction or “splitter” boxes.
“How many ducts can come out of these boxes before it impacts the air temperature and distribution? One? Three? Five? That’s what we need to find out,” said IBACOS Services Manager Anthony Grisolia (pictured left), who proposed the project.
With the support of Carrier Corporation, IBACOS is currently conducting research that will examine the airflow in three common distribution box designs and sizing criteria, and is taking measurements to determine the effect of system design on air delivery temperatures.
This research could have significant real-world implications, said Anthony.
“This project could point the way to establishing a set of standards for HVAC contractors to use when working with these distribution boxes,” he said. “ENERGY STAR guidelines also have a checklist for mechanical contractors requiring they install according to the ACCA Manual D, so the impact could be pretty big.”
He added that flex duct HVAC systems are not the efficiency standard in the industry, like the trunk and branch system. But IBACOS knows that this approach remains widespread and believes a contractor can achieve high performance with flex duct systems.
“Trunk and branch may be best, but the majority of new construction and existing homes in the southern U.S. have flex duct systems, and that’s going to continue to be true for some time,” he said.
“We just hope to provide information that could improve industry standards, as well reduce energy consumption.”
