PNNL Researchers Developing Air Conditioning System for Troops Overseas
RICHLAND, Wash. -- Researchers at Pacific Northwest National Laboratory are working with the Department Of Defense , the Navy as well as the private industry on a special project that could help save the lives of our troops serving overseas.
And it all begins with air conditioning. About a dozen researchers at the lab have signed up to use $2.8 million over three years to develop a cooling system that operates more efficiently that what's currently in place at bases overseas in war zones like Iraq and Afghanistan.
The projects was among five awarded a total of $8.5 million to improve the efficiency of battlefield heating and air conditioning systems by 20 to 50%
Researcher Pete McGrail, who is part of the PNNL team says the current method of providing electricity is through diesel fuel. He says it is pricey and dangerous for the military personal making the deliveries.
"It costs about $40 to $400 per gallon. So its very expensive and its also a dangerous operation for the troops that have to deliver that fuel to the bases," said McGrail.
So they are working on an alternate plan. PNNL's system will be a next-generation adsorption chiller that is specially designed to be smaller, lighter, more efficient and operate under the extreme temperatures experienced at bases on the front lines.
"We really need to succeed on this, so we can have an impact on the safety of the troops that are protecting us on the front lines," said McGrail.
The chiller will use a specially created powder, called a metal organic framework, or MOF. The powder is made of metal clusters connected to organic molecules, or linkers. Together, the clusters and linkers assemble into porous 3D structures that absorb water easier than how it is done in regular air conditioning systems.
This helps make PNNL's test adsorption chiller system much smaller and lighter. Further improvements for this project will include breakthroughs in microchannel heat exchanger technology and improvements in the MOF's thermal properties. Both advances will help reduce the size and weight of the chiller further and squeeze out more cooling efficiency.
"This will be the most advanced adsorption cooling system ever developed, and these advances are needed to meet very demanding military requirements," McGrail said.
PNNL's military system will run off of waste heat coming from a diesel generator. This could reduce the diesel fuel use needed to cool field military installations by up to 50 percent. The planned 3-kilowatt unit will weigh about 180 pounds and take up about 8 cubic feet.
PNNL will also work with ADMA and Texas A&M University to develop an energy-efficient, compact dehumidification and evaporative cooling system that removes water vapor from humid air.
Direct evaporative cooling systems, sometimes called swamp coolers, don't work well with moisture-rich air. . To make evaporative cooling more efficient, this system will use a package of foil-like membranes made of a porous metal sheet coated with a layer of a water-attracting material called zeolite that removes water vapor from air. The resulting dehumidified air can be cooled with water recovered from the zeolite. The new system allows evaporative cooling to work in various climates with minimal water consumption. In hot, humid environments, the military estimates it could use 20 to 50 percent less fuel for cooling with this system.
PNNL Chief Engineer Wei Liu is leading PNNL's contributions and is helping manage the overall project. The novel membrane dehumidifier is based on inventions made by Liu and his team at PNNL.