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MICROCHANNEL HEAT EXCHANGERS
MCHEs: ADVANCED HEAT TRANSFER TECHNOLOGY( PART 1)
By Patrick Burke, FSAIRAC, RPM Consulting Engineers
How microchannel technology is shaping the future of HVAC & R. This is part one of a two-part series. voices
All images supplied by Pat Burke
The development of microchannel technology now offers the air-conditioning, refrigeration and process cooling industries a compact high-efficiency heat exchanger option for use throughout, with proven superior thermal performance and greatly reduced environmental impact, when compared with the traditional tried-and-tested heat exchangers we are all familiar with.
With the advent of microelectrochemical systems in the early 1980s, the concept of microchannel technology came about, followed by broader applications for their use, including the development of microchannel heat exchangers( MCHEs) for various industries, and in our case, HVAC & R.
Automotive air-conditioning systems were among the first to adopt MCHEs due to their compact size and high efficiency, where both space and weight are critical factors. This technology soon evolved and expanded into the HVAC & R and process cooling markets.
RACA Journal I February 2026
TECHNOLOGY OVERVIEW MCHEs consist generally of flat aluminium tubes with multiple small channels( microchannels) through which the refrigerant flows. The flat tubes are sandwiched between fins, increasing the surface area for heat exchange, thus enhancing thermal performance. Suitably designed headers and manifolds distribute refrigerant evenly across the microchannels.
When designing the relevant MCHEs, the key parameters comprise channel diameter, tube and fin material, fin thickness( density) and of course, the type of refrigerant for use. Compared to the traditional copper tube / aluminium fin heat exchangers, MCHEs deliver a higher heat transfer coefficient, significantly improving thermal performance. Their compact design and low weight ratio allow for applications where space and weight restrictions prevail.
As a result, the reduced refrigerant charge decreases the environmental impact considerably and in turn, overall operating costs. Typically constructed from aluminium, MCHEs furthermore offer excellent durability in terms of both corrosion and scale resistance levels. In addition, MCHEs, by virtue of their design, ensure a lower air-side pressure drop. This reduces fan power, lowering energy consumption, thereby improving overall system efficiency.
One must avoid the misconceived belief that MCHEs represent the‘ be-all and end-all’ in terms of heat exchanger application and design.
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