Scientists in Singapore have developed an innovative new cooling method for electrical systems.
The new technique, developed by Dr. Lee Poh Seng from the Department of Mechanical Engineering at the National University of Singapore, is based on the use of phase-change “flow-boiling” and involves the combination of two different types of heat sinks within a single system – microgaps and stepped fin microchannels.
Tiny microgaps, measuring between 80 and 1000 microns in size, are distributed on surfaces to expedite temperature reduction by permitting the ingress of liquid coolant flowing through the system and enhancing its ability to absorb heat.
The liquid coolant rapidly reaches its boiling point in the microgaps following the absorption of heat, causing it to transition from a liquid to a vapor state. This ensuing phase change also permits the absorption of latent heat.
The efficiency of the heat dissipation achieved via use of these microgaps is further heightened by the incorporation of stepped fin microchannels.
In order to ensure the liquid coolant is able to successfully undergo phase change, the scientists had to precision tailor the size and distribution of the microgaps so that the resulting texture would be just coarse enough to permit the formation of vapour bubbles.
According to Lee, it took his team two years to ascertain the ideal dimensions and pattern of distribution for the microgaps. This entailed recording the boiling regime using high-speed cameras as well as the use of the footage for data extraction and detailed analysis.
According to the NUS engineers,the technique could prove to be 50 per cent more efficient than existing cooling methods for electrical systems. It is also cuts down on equipment costs and energy consumption by dispensing with the need for large pumps to induce movement of the coolant.
The technique is scalable in both directions and can be used on set ups as large as nuclear power plants or as small as portable electronic devices such as laptop computers.
The team expects to produce a prototype of a the cooling system to be ready by early 2014.