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Feature
Supplied by HC Heat Exchangers Supplied by Evapco
A larger process cooling heat exchange .
exchanger design for ultra-low temperature vaccine storage , demonstrating the technology ’ s adaptability and potential . The heat exchanger market is poised for substantial growth , driven by increasing efficiency demands , emerging economies expanding manufacturing capabilities , and the rise of renewable energy systems and electric vehicles . Microtechnology and electronic developments are also pushing the boundaries of heat exchanger applications , including microenergy generation systems .
To stay competitive , manufacturers must invest in product innovation and R & D . Advances in heat exchanger technology , including new techniques and materials , are expected to further drive market growth and enhance efficiency .
PRINCIPLES AND DESIGN CONSIDERATIONS Heat transfer theory dictates that heat moves from a hot medium to a cold one until equilibrium is achieved . Heat exchangers ( HEX ) facilitate this transfer between fluids separated by a barrier ( indirect HEX ) or in direct contact ( direct HEX ). Factors influencing heat exchanger design include flow rates , pressure , temperature parameters , and maintenance needs . Different applications require specific designs , such as tube sizing and fin spacing , to optimise performance and efficiency .
A coil set for an ice storage installation is another example of the heat exchange design .
Maintenance is crucial for the longevity and efficiency of heat exchangers . Regular inspections , cleaning , and checks of electrical connections and mechanical components are essential to prevent performance degradation and ensure system reliability . For instance , coil heat exchangers should be visually inspected monthly , with thorough cleaning every three to six months .
Design errors often arise from incorrect pipe sizing , valve fitment , and coil placement . Additionally , assuming all fluids have the same properties can lead to inefficiencies . Accurate information on fluids and system limits is critical for optimal heat exchanger design .
Product footprint remains a significant consideration due to smaller plant room sizes . Innovations such as integrated condensers and compact designs are becoming increasingly popular . New heat exchanger technologies , including advanced gasket plate designs and asymmetric channels , are improving efficiency and reducing fouling , offering long-term benefits and cost savings .
As heat exchangers continues to evolve , ongoing research and technological advancements promise to address modern challenges and push the boundaries of efficiency and performance .
TRANS-CRITICAL CO 2
SYSTEMS Marius la Grange , general manager : Thermocoil , explains that few traditional HVAC & R applications remain as unsuited for CO 2 as refrigeration but the main industry that has rapidly applied and fine-tuned the CO 2 trans-critical technologies would be the retail sector . This is because retail has a big focus on running costs / energy consumption and life cycles .
CO 2 is used in various types of heat exchangers for specific applications . “ Similar to HFC systems , evaporators absorb heat energy , while gas coolers reject heat energy . The gas cooler acts as a condenser at low to moderate ambient temperatures and functions as a gas cooler at high ambient temperatures .”
How CO 2 compares to traditional refrigerants in terms of efficiency depends on the operating temperatures and the ambient conditions where the system is functioning . “ The lower the ambient temperature where the system is installed , the more hours each year a CO 2 system will operate in subcritical mode . A refrigeration system operating in sub-critical mode is likely to be more energy-efficient than a comparable HFC system .
“ The main advantage of R744 ( CO 2
) is its energy efficiency across a wide range of operating temperatures . In industrial applications , CO 2 competes with ammonia . In some cases ,
CO 2 is chosen primarily because of its lower capital cost , even if ammonia is more energy efficient . HFCs are generally not considered in these situations .”
As to how CO 2 impacts the design and operation of heat exchangers , La Grange explains that the operating pressures are significantly higher than in traditional HFC systems . An HFC
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RACA Journal I November 2024 www . refrigerationandaircon . co . za