Page 21 - Climate Control News July 2019

Heat Exchangers
Dimple design is a gas for thermal efficiency
HOW IT WORKS AT A GLANCE
The new Hybrid Indirect Cooler (HIC) enhances the performance of the highly efficient rotary heat exchanger by combining a small- refrigerated Heat Pump to produce cooled dry fresh air, with very little energy usage. This indirectly cools and dehumidifies hot humid 100% fresh air to the building.
A further sustainable benefit is its ability to produce clean water condensed directly from humid air when used in humid environments.
Because the performance of these systems improves dramatically as ambient temperature rises, even to extreme conditions without fear of shutdown, they may provide an added sustainability benefit in reducing the risks of power grid failure.
The indirect evaporative cooler of the HIC uses the most environmentally acceptable of all known refrigerants, water. In dry climates, the indirect cooling reduces the quantity of water used by the IEC. In humid climates, the HIC can become a net producer of clean water condensed directly from the fresh air, while using a small conventional heat pump of about half the size that would be required if the hybrid cooler were not applied. For environmental reasons the small HP unit may also be using an environmentally acceptable refrigerant such as CO2.
ALFA LAVAL’S NEW gas-to-liquid plate heat exchanger portfolio revolutionises gas cooling duties.
Alfa Laval’s new portfolio of gas-to-liq- uid plate heat exchangers is specifically engineered to meet the needs of gas cool- ing duties.
The compact technology can handle ex- ceptionally high temperatures and the challenges of simultaneously working with both gas and liquid media.
Cooling duties involving gas media are a challenge for many businesses, who have traditionally been forced to settle for bulky and inefficient shell-and-tube technology.
Alfa Laval’s new gas-to-liquid plate heat exchangers offer much greater thermal ef- ficiency with a footprint around 75% smaller than shell-and-tubes used in the same applications.
While Alfa Laval has long had a compre- hensive offering of efficient brazed plate heat exchangers, the new portfolio takes the product range a step further.
Thanks to a revolutionary “dimple” plate design in a patented asymmetric configuration, the new units are opti- mised to handle the distinct challenges of dealing with gas media.
This design enables very low pressure drop in applications that have dispro- portionate flow rates between the two media. Moreover, while standard brazed plate heat exchanger supports media temperatures up to 225°C, the gas-to-liquid portfolio can handle gas temperatures of 750°C without suffer- ing thermal fatigue.
“IT OFFERS GREATER THERMAL EFFICIENCY WITH A 75% SMALLER FOOTPRINT THAN SHELL AND TUBE EXCHANGERS.”
Due to the technology’s combination of high condensation rate with high thermal efficiency, Alfa Laval’s gas-to-liquid port- folio delivers advantages in waste heat re- covery, air compressors as well as applica- tions in charge-air coolers.
The initial launch of the gas-to-liquid portfolio features two product ranges with models in various sizes. The GL range features a counter-current channel arrangement to optimise thermal efficien- cy. The GLX range has a cross-flow ar- rangement and is designed with open in- lets and outlets on the gas side to provide the lowest possible pressure drop.
Visit alfalaval.com.au
“I have applied for a provisional patent on a new con- cept low energy cooler based on an extension of my work on Indirect Evaporative Coolers which was the subject of a paper I presented recently,” he said.
The New concept cooler, which is applicable for all climates, is known as the Heat Pump Indirect Evapo- rative Cooler (HPIEC).
“This will use the highly efficient rotary sensible heat exchanger (RHE) to indirectly cool and dehumid- ify hot humid fresh air, utilizing a small conventional vapor compression refrigerated heat pump (HP) and a highly efficient evaporative cooler (EC),” Ellul said.
“My modelling studies show that it should economi- cally produce comfortable cool, dry 100% fresh air in all climatic conditions.
“The RHE becomes the major contributor to this process providing free cooling and free dehumidifica- tion resulting in very high COP.
“This also dramatically reduces the water require- ment of the EC and the cooler can become a net pro- ducer of clean fresh water, which it extracts from the humid fresh air,” he said.
“The overall efficiency of this cooler will substantially exceed that of any other type of refrigerated HP coolers.” Ellul is ready to test his HPIEC against solutions
from around the world.
GLX range offers exceptional thermal efficiency
CLIMATE CONTROL NEWS JULY 2019
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