A big advancement for variable refrigerant flow (VRF) technology in a smaller package, CITY MULTI N-Generation high-performance outdoor units deliver enhanced energy efficiency and personalized comfort control for commercial building applications. This enhanced performance caught the attention of the contest's panel of engineering judges, which selected this unit as the 2021 Commercial Comfort Product of the Year in the VRF category.

The N-Generation features a footprint up to 30% smaller than previous models and expands vertical piping limits from 164 feet to 295 feet. The system’s branch circuit (BC) controllers offer a height reduction, service access from the bottom, and the ability to connect up to 11 sub-BC controllers to one main BC controller.

“These benefits increase design flexibility while reducing costs for time and materials,” said James DeBerry, commercial marketing manager, Mitsubishi Electric Trane HVAC US. “With the addition of 16-, 18-, and 20-ton single module units, we worked to ensure this generation of CITY MULTI outdoor units is able to provide superior, customizable zoned comfort for occupants — all while increasing the system’s efficiency and shrinking its footprint for the benefit of building owners and facility managers.”

Now available in a tiered lineup, the N-Generation outdoor units can meet a variety of unique applications and climates with standard, high-efficiency, and Hyper-Heating INVERTER® (H2i®) models. A four-sided heat exchanger, compressor, and fan blade design improve both nominal and seasonal efficiency levels, even at part-load conditions. The introduction of 16-, 18-, and 20-ton single-module heat recovery units completes the lineup of CITY MULTI N-Generation high-efficiency models.

The CITY MULTI N-Generation units also feature built-in flash-injection technology for improved heating performance (in high-efficiency and H2i models); reduced sound levels with decibel levels as low as 56.5; and optimized tools for monitoring and maintenance.

In addition, CITY MULTI N-Generation introduces five new airflow settings. Coupled with the redesigned compressor and fan, these innovations reduce noise levels across all models. The enhancements also increase both nominal and seasonal efficiency levels for an up to 27% IEER improvement over prior generations, even at part-load conditions. The unique flat-tube aluminum heat exchanger (high-efficiency tier) is designed to ensure maximum heat transfer and efficiency, translating to operational cost savings and superior comfort for occupants.

CITY MULTI N-Generation Outdoor Units allow for streamlined design, installation, and maintenance.

“Built-in data storage, accessible via USB, stores up to five days of operational data,” DeBerry said. “Using the Maintenance Tool, service professionals can more easily diagnose and troubleshoot the VRF system. Our latest BC controllers feature a height reduction and service access from the bottom.”

More than three years of research went into the design of CITY MULTI N-Generation, and a variety of research methods were used in the creation and testing of this product, including voice of customer research, chamber extreme condition testing, and field testing.

The Judges Have Spoken

For one judge, the CITY MULTI N-Generation’s size and adaptability pushed it to the top spot.

“By using only the precise amount of energy required to meet a set point, these VRF units can help a facility manager minimize energy use and, ultimately, maximize cost savings. These units are also exceptionally versatile, as they come in 16-, 18-, and 20-ton models, allowing designers to use them in multiple configurations.”

Another judge continues to be impressed with how Mitsubishi Electric Trane HVAC US continues to evolve its VRF units’ efficiency levels.

“The CITY MULTI VRF systems have always been ahead of the curve, and these units show that they intend to stay there,” he said. “They’re quiet, efficient, small, and can be used in numerous combinations. What’s not to like?”