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Lab Breakthrough: Desiccant Enhanced Evaporative Air Conditioning

May 29, 2012 - 5:22pm

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This breakthrough combines desiccant materials, which remove moisture from the air using heat, and advanced evaporative technologies to develop a cooling unit that uses 90 percent less electricity and up to 80 percent less total energy than traditional air conditioning. This solution, called the desiccant enhanced evaporative air conditioner (DEVAP), also controls humidity more effectively to improve the comfort of people in buildings. View the entire Lab Breakthrough playlist.

National Renewable Energy Laboratory's Eric Kozubal co-invented an air conditioning system that's energy efficient while incredibly effective at both cooling a building and managing its humidity levels – the first time both of these processes have been fit into a single machine. Kozubal recently talked to us about his invisible technology, its road to commercialization, and the effects it will have on industry.

This Q&A and video are part of the Lab Breakthrough series, which highlights innovations developed at the National Labs.

Question: This is a perfect example of ‘invisible technology.’ How would someone walking into a building know the DEVAP was being used?

Eric Kozubal: The desiccant enhanced evaporative air conditioning (DEVAP) would be just as invisible as any other cooling system in a building. However, in hot humid climates, occupants might notice that the building has a comfortable humidity level, and doesn’t need to be overcooled. The biggest advantage may be what the occupants don’t experience — stuffiness in the buildings space, lack of fresh air, and high humidity. The building owner will certainly appreciate reduced energy bills because of the estimated 40 to 80 percent energy savings DEVAP can provide over traditional air conditioning.

Q: Would we be more likely to see this technology used in a commercial or residential building?

EK: Commercial markets will be the first target for product roll-out because the financial and energy payback for efficient air conditioning is much higher in commercial buildings.  Once the product is well-established, a residential roll out will surely follow.

Q: What’s the next step for getting this innovation out into industry?

EK: DEVAP will require additional development to get to a field prototype stage.  Although the cooling cycle is largely proven through laboratory testing, we need to make it smaller, cheaper, reliable and manufacturable. This process will require support by the Energy Department, NREL and the HVAC industry. 

Q: Why hadn’t these two technologies – desiccant and evaporative processes – put together in the past?

EK: There have been attempts to put these technologies together, but technical issues prevented successful development. NREL took advantage of recent materials advances and liquid desiccant advances to design a compact and cost-effective system.

We discovered the value of using micro-porous membrane technology to maintain the necessary liquid and air separation in the heat and mass exchanger -- the component of the air conditioner that dehumidifies the air. In addition, we demonstrated indirect evaporative cooling with cooling effectiveness never thought possible -- and better than any product available today. This is an important achievement that ensures that DEVAP is energy efficient.

We could not have used an off-the-shelf indirect evaporative cooler. The combination of desiccant dehumidification and highly efficient indirect evaporative cooling creates the unique, patented, DEVAP AC process.

Q: What about your facilities specific resources made it the right place to develop this technology? 

EK: For more than 25 years, NREL has had researchers dedicated to working on desiccant and evaporative air conditioning technologies. NREL’s unique HVAC laboratory was built to rapidly and accurately measure the performance of prototypical HVAC technologies. The lab’s capabilities allow researchers to validate performance along with the precision to accurately and definitively guide the development of products.

The combination of becoming familiar with these technologies in a highly detailed way, and the creativity of our researchers resulted in an “aha” moment.

Q: For a young student, engineer or researcher looking to make their own breakthroughs, do you have any words of wisdom?

EK: All new inventions today require innovative thought processes. Inventors must look across multiple fields of technologies and see where they can come together to create value.  Innovation in today’s advanced society requires an aspiring engineering to sit back and think -- think hard about what makes sense. This is a necessary step to finding new ways of improving the way we live, creating value. I’m sure people could accuse me of staring off in the distance for quite a bit of time. However, I can assure you I was hard at work - thinking.  Of course, none of that thinking is valuable until you make it a reality. The challenge is then to create something.

Visit the Lab Breakthroughs topic page for the most recent breakthroughs highlighted in the video series.  

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