Ozone Infused Water Sanitizes Food

As a former environmental chemist, I love hearing about technologies that reduce our impact on the environment as well as provide companies with a competitive advantage. I recently learned about one such technology. Ozone International, one of Lytron’s customers, manufactures environmentally-friendly ozone-based cleaning and sanitizing systems for use in the food and beverage industry. Unlike chlorine, ozone is considered safe for direct-food contact applications and is not harmful to the environment. It is also more effective than chlorine at killing bacteria. According to Ozone International’s website, their chemical-free systems reduce sanitation time, labor costs, hot water consumption, and harmful chemicals, while offering increased food quality and shelf life. The company’s system generates ozone onsite using ambient air and a small amount of electricity. The system takes in ambient air, filters the air so that only pure oxygen gas remains, and then passes the oxygen gas through a high voltage field. This high voltage field, like lightning, excites the oxygen gas to create ozone (O₃). The ozone gas is then injected into a low-pressure stream of cold water, and this ozone-infused water is then distributed throughout a processing facility via PVC or stainless steel piping. So where do Lytron’s thermal solutions come into play? Lytron’s 6105 tube-fin heat exchangers are used to cool the air from the compressor that feeds the oxygen concentrator. Do you use a Lytron product for your green technology? Please let us know!    

WhiteWater System Image Courtesy of Ozone International

International Space Station Image Courtesy of NASA

Although most of us aren’t working in conditions quite as critical as those encountered on the International Space Station (ISS), the majority of us are very concerned with the uptime of our systems. On Saturday a liquid cooling system on the International Space Station malfunctioned, forcing the crew to power down some of the station’s vital systems. The downtime situation aboard the ISS serves as an excellent reminder about the importance of designing in redundancies on critical systems, as well as the importance of having spare parts readily available.

The malfunction on the ISS was the result of a pump module failure in one of the station’s two large liquid cooling loops. The second, or backup, cooling system is keeping the ISS up and running; however the station still has some of its operations shut down as the backup alone cannot handle 100% of the operations. The crew plans to replace the pump module this week with one of two backup pump modules that is located on the station. Although the backup pump module must be retrieved via a spacewalk, at least it didn’t have to be sent up from Earth!

The space station’s liquid cooling systems remove waste heat from electronics using cold plates and heat exchangers. There are two separate cooling loops within each cooling system. The process side cooling loops inside of the space station use water as the coolant while the external cooling loops use liquid ammonia to prevent freezing.

In a Space.com article about the malfunction, Denise Chow writes, “…while the intricacy of all the space station’s parts can sometimes lead to technical problems, the interaction of these complex systems is also what has kept the station operating successfully for over a decade.” According to Boeing, it was the first malfunction of the cooling system.

Cooling systems used for many applications, including data center cooling, medical equipment cooling, or manufacturing process cooling, are often considered “mission critical” equipment. To address this, Lytron can design and manufacture cooling systems with redundancies as well as other features to help ensure uptime. For example, Lytron’s LCS50 liquid cooling system for data centers has redundant pumps, optional redundant modulating valves, and isolation valves for hot swapping of all major components. Lytron also offers spare parts for its cooling systems.  

Sources:

http://www.space.com/businesstechnology/international-space-station-complexities-100802.html

http://www.nasa.gov/mission_pages/station/main/index.html

http://www.nytimes.com/2010/08/02/science/space/02shuttle.html

Dental Laser Heat Exchanger

Medical lasers often require liquid cooling to maintain a precise laser wavelength and higher output efficiency, to achieve desired beam quality, and/or to reduce thermal stress on the laser system. Pictured on the left is a custom stainless steel tube-fin heat exchanger that Lytron recently designed and manufactured for an OEM for cooling a dental laser. Although the custom stainless steel tube-fin heat exchanger is very similar to Lytron’s 4000 series standard stainless steel tube-fin heat exchanger, it has custom dimensions to meet the OEM’s specific requirements.

Dental lasers require a stainless steel fluid path in the heat exchanger if they are using deionized (DI) water to cool the laser’s diodes. Unlike copper and aluminum, stainless steel is compatible with DI water and other corrosive fluids. For more information, please review our application note, “Liquid Cooling a Laser for System Optimization.”

Vacuum Chamber and Helium Leak Detector

Lytron recently purchased a new vacuum chamber and helium leak detector for testing custom cold plates and custom heat exchangers for aerospace applications. The helium leak detector can identify leaks of down to 10^-12 mbar l/s.  The vacuum chamber is 50″ (127.00 cm) long and 30″ (76.20 cm) in diameter and can be used to test parts up to 44″ (111.76 cm) long and 29″ (73.66) wide. The purchase of the vacuum chamber and helium leak detector  further expands Lytron’s in-house  test capabilities. For more information, please contact Lytron at +1-781-933-7300.

SEM Image of Alumina Nanoparticles Courtesy of Olin College of Engineering

Research continues for ways to improve the performance of cold plates and heat exchangers to handle increasingly high heat load densities for electronics cooling. Dr. Jessica Townsend, assistant professor of mechanical engineering at the Franklin W. Olin College of Engineering, recently published a paper on nanofluids with her colleague Dr. Rebecca J. Christianson, assistant professor of applied physics. The paper, “Nanofluid Properties and Their Effects on Convective Heat Transfer in an Electronics Cooling Application,” shows some very promising results in the use of nanofluids for liquid cooling.

The findings of Dr. Townsend’s and Dr. Christianson’s research included up to an additional 8°C reduction in chip temperature when a 1% volume fraction of alumina-in-water nanofluid was used as the coolant in a liquid cooling loop in place of deionized water. Alumina-in-water at a 2% and 5% volume fraction was also investigated but resulted in a much smaller decrease in junction temperature.

Dr. Townsend and Dr. Christianson are planning future experimental studies to look at whether nanofluid thermal conductivity increases anomalously with temperature and whether nanoparticle size is a factor. This could result in the potential to “tune” nanofluids for more effective performance at particular temperature ranges.

Townsend, J, Christianson, R. J., 2009, “Nanofluid Properties and Their Effects on Convective Heat Transfer in an Electronics Cooling Application,” Journal of Thermal Science and Engineering Applications, Transactions of the ASME, Vol. 1 / 031006-1.

Faulkner, D. J., Rector, D. R., Davidson, J. J., Shekarriz, R., 2004, “Enhanced Heat Transfer Through the Use of Nanofluids in Forced Convection,” Proceedings of the 2004 ASME International Mechanical Engineering Congress and Exposition, pp. 219-224.

Lee, J., Mudawar, I., 2007, “Assessment of the Effectiveness of Nanofluids for Single-Phase and Two-Phase Heat Transfer in Micro-Channels,” International Journal of Heat and Mass Transfer, 50(3-4), pp. 452-463.

Chein, R., Chuang, J., 2007, “Experimental Microchannel Heat Sink Performance Studies Using Nanofluids,” International Journal of Thermal Sciences, 46(1), pp. 57-66.

Valencia, G. E., Ramos, M. A., Bula, A. J., 2007, “Experimental Evaluation of the Convective Heat Transfer Coefficients in a Nanofluid-Cooled Milli Channels Heat Sink,” Proceedings of the 2007 ASME International Mechanical Engineering Congress and Exposition, pp. 31-37.

DatacenterDynamics

Lytron will be exhibiting its new LCS50 at the DatacenterDynamics tradeshow in San Francisco on July 16th. The LCS50 Coolant Distribution Unit (CDU), a liquid-to-liquid cooling system, supplies coolant at precisely controlled temperatures to liquid cooled cabinets. In addition to cooling systems, Lytron also designs and manufactures cold plates and heat exchangers for liquid cooling in data centers. If you plan to attend the tradeshow, please visit us at our booth!  

Plate-Fin Oil Cooler

Lytron frequently receives questions through its “Ask an Engineer” website form. A customer recently asked us the following question: “What custom heat exchanger technologies do you recommend for cooling oil?”

There are two heat exchanger technologies that we typically use for custom oil coolers: flat tube and plate-fin. Both are vacuum-brazed and high performance. If flat tube will meet your thermal and mechanical requirements, we will generally recommend it over plate-fin because flat tube typically costs less to manufacture.

Curved Flat Tube Heat Exchanger

In addition, our flat tube can be bent into a 3⁄8˝ (3 mm) inside radius without buckling, allowing us to manufacture a flat tube heat exchanger into a curved shape if necessary.

Tube-fin heat exchangers are also an option for cooling oil, but their performance is not as high as flat-tube or plate-fin heat exchangers.

For applications requiring the highest performance and the lightest weight, we will generally recommend plate-fin heat exchangers over flat tube heat exchangers. The majority of military and aerospace oil coolers being designed today use plate-fin technology. Shown in the image to the left is a liquid-to-liquid plate-fin oil cooler designed for a commercial airplane.