Oki Printed Circuits Co., Ltd. has showcased a new type of watercooled printed circuit board (PCB) to Nikkei Business, which it calls the
"Conduit-incorporated Printed Board." In conventional watercooling
systems, just the upper surface of an integrated circuit, chip
or processor is cooled by a metal block that has space inside for water to
continuously pass through. These types of heatsinks are generally know as
"waterblocks" or "watercooling jackets". Since the heat produced by a
microchip soldered to a PCB is conducted out the top, and through the
solder balls which hold it onto the PCB through the bottom, this form of cooling
is not entirely efficient. Oki's new conduit incorporated PCB is an alternative to these water-cooling jackets because it contains a coolant
flow channel to cool board mounted electronic devices from above, and below.
According to the company, "the conduit-incorporated
printed boards will be located on the upper and lower surfaces of the exothermic component. All
of the parts required for cooling, such as a radiator for heat
dissipation, a pump and a reservoir for coolant are imbedded on the Conduit-incorporated
printed board."
"As a result, the conduit-incorporated printed board has the following
characteristics: (1) cooling systems can be miniaturized as all of the required
parts for a cooling system can be imbedded on the printed board; (2) the cooling
capacity is high as the exothermic component is cooled from both surfaces, and
(3) multiple exothermic components on a printed board can be cooled, the company
explained."
(Image credit: Nikkei Business Publications) In the protoype configuration shown above, a synthetic heater is sandwiched between two
conduit-incorporated printed boards from the upper and lower surfaces of the
heater. "The heat conductive pads, which have a coefficient of thermal
conductivity of 5 W/m·K, are sandwiched between the heater and the
conduit-incorporated printed board on both heater surfaces. The initial
temperature of the coolant is 24° C; the room temperature is 19° C; and the
electric consumption of the heater is 14 W. The result shows that this system
can achieve roughly a 32% reduction in temperature rise in comparison with a
system to water-cool the exothermic component from one surface."
(Image credit: Nikkei Business Publications) For circuit boards with
electronic packages of different height, the difference is accomodated by heat conductive
pads.
