USA – Mitsubishi Electric’s Cooling & Heating Division have unveiled their latest innovation in Variable Refrigerant Flow (VRF) technology, the City Multi L-Generation Air Source outdoor units. The efficiency ratings for the L-Generation (6 to 30 tons; single modules up to 14 tons) have been significantly improved compared to previous models via HexiCoil technology, an aluminium flat tube heat exchanger that the company claims maximizes heat transfer capability due to its unique fin shape. The increased efficiencies that have been recorded across all categories due to the new technology render this outdoor unit suitable for projects which have efficiency goals such as LEED^® certification or net-zero status.

“The L-Generation, with its HexiCoil technology, represents a significant enhancement in efficiency and operation for the VRF category,” declared Kevin Miskewicz, senior manager, commercial marketing, Mitsubishi Electric US, Inc. Cooling & Heating Division. “This coil redesign includes turbulated tube walls and an optimized cross section, ensuring maximum heat transfer ability. This advancement directly leads to improved efficiencies, particularly at part load conditions.”

The company are confident that the fin design of the HexiCoil product, and also its zinc outer coating, will provide superior water shedding capability and corrosion resistance, thereby helping to extend the outdoor unit’s lifespan. The outdoor unit also has a capillary tube system which should help ensure more even fluid distribution and further contribute to the unit’s heat transfer ability.

Mitsubishi also claim that the new L-Generation outdoor units will deliver a 30% smaller footprint than previous models and will result in a reduction in system refrigerant charge of up to 50 percent due to changes in the refrigerant circuit design resulting in improved flow distribution. The company further boast an improvement in the high-ambient cooling operating range, allowing for cooling operations at temperatures up to 52°C while an increase in the vertical separation between indoor units within the same heat recovery system will further expand design options.

The outdoor units have been designed to operate as quietly as possible, at noise levels in the 58 to 65 dB (A) range. All models in the L-Generation series of air source outdoor units now include a bellmouth grill with a DC fan motor in the drive to reduce static pressure while simultaneously minimizing the power input.