DNA Lab Freezer System Has The Right Code
That project is a collaborative international research program that is constructing genetic and physical maps of the human genome to determine the patterns that make up human DNA.
“Our library of code samples is growing by leaps and bounds every month,” said Whitehead’s Director of Physical Plant John Shearns. “We need to be able to store and retrieve samples with increased efficiency to keep up the pace.”
So, Whitehead decided to install a robotic retrieval and storage system inside a custom-made freezer manufactured by American Insulated Panel Co. The freezer is located on the laboratory floor.
COMPLEX SPECSThe refrigeration specifications for the new freezer were complex. There was lack of space on the floor to locate a large freezer box and the mechanical equipment together. As it is, the box is wedged between two pillars and a low ceiling.
“With the robot and shelves of samples inside the box, there was no room to install a fancoil,” said Bob Stone, service manager for Winchester Mechanical Service Co., which does much of the HVACR work for Whitehead. “We only had a half inch of free space outside the box to work with in installing this equipment.”
Mark Potenza of ABCO Refrigeration suggested using a Bohn air handler because of “the variety of air distribution options it offers.”
Over the next five months, an air-handling and duct system was custom built to provide cooling to the 8- by 23- by 12-foot freezer.
“What clinched it for us was the small size of the air handlers and the flexibility of air discharge offered,” said Stone. Many air handlers discharge from only one side of the machine, but Bohn offered air handlers that discharge on whichever side is required.
“Air handlers in freezer applications are novel,” said Stone. “But we got extra input from Bohn.”
The installers also liked the hinged access panel and motor-mounting options. These options allow a service tech to flip a latch in order to open a hinged panel and work on a motor where it can most easily be accessed.
The system must maintain a temperature of –5 degrees F even as a 35- by 7-inch window automatically opens up to 900 times daily for a period of 30 seconds each time, so the robot can pass 20,000 DNA samples in or out. On top of that, the robot itself creates a heat load on the equipment. Both factors caused the decision to actually install two mechanical systems.
“One system was enough” for conventional refrigeration, said Stone; “but with the robot heating up the freezer, we decided to go with two systems to ensure reliability.”
For more information, contact Bohn, a Heatcraft Refrigeration brand, Stone Mountain, GA, at 770-465-5600 or www.heatcraftrpd.com (website).
Publication date: 12/02/2002