Variable refrigerant flow heating and cooling systems are known for outstanding energy efficiency. By moving liquid and gas refrigerant through small-diameter pipes — instead of air through larger ductwork — these “ductless” systems offer numerous benefits for many structures, from historic buildings to new construction.
Still, a perception exists that ductless systems aren’t feasible for many buildings, zones and spaces — either due to technological limitations, budgetary constraints or the availability of capacities to precisely meet the needs of the space.
With every passing year, more of these challenges to ductless systems no longer apply. Leading manufacturers like Trane now have ductless system portfolios that can serve more applications of all sizes than ever before — affordably, reliably and while delivering exceptional comfort and user control. This article examines systems that historically have been underserved by ductless solutions, but now can benefit from ductless offerings from more manufacturers than ever before.
Single-zone ductless systems match one outdoor condensing unit with one indoor fan coil unit, offering simpler, faster, lower-cost installations to serve capacity needs typically ranging up to four tons. Smaller single-zone ductless solutions can be ideal for single rooms such as media rooms, elevator rooms, auxiliary building spaces and more. They can serve as standalone temperature-control solutions or as a supplement to larger HVAC systems. Ductless systems are also well suited to function in cooling-only mode for control of temperatures in small spaces that contain heat-generating equipment, such as computer server rooms.
The newly expanded Trane portfolio of ductless solutions brings legendary reliability and exceptional ductless efficiency to smaller single-zone systems, and can deliver heating and cooling capacities from 3/4 ton to 4 tons, with efficiency ratings of up to 27 SEER.
Multi-zone systems connect multiple indoor fan-coil units to a single outdoor condensing unit, offering high-efficiency, room-specific temperature control for spaces ranging from as small as a few rooms to as large as an entire building. In many configurations, multiple outdoor condensing units can be combined to produce larger system capacities.
Smaller multi-zone systems haven’t always been adequately served by the marketplace, but newer design strategies now bring this kind of individualized comfort, installation versatility and operating-cost savings to a wider variety of installations than ever before. The existing Trane portfolio of multi-zone ductless solutions has been expanded with solutions specifically designed to meet smaller-space needs, serving from two to five indoor fan-coil units with a single outdoor condensing unit and delivering a 16 SEER efficiency rating.
In the past, ductless systems often weren’t considered for large-capacity needs. Today, using several ductless units to serve a single large-capacity application is a viable option: A single Trane modular ductless VRF outdoor unit has a capacity of up to 48 tons and can be part of a multiple-unit system that delivers hundreds of tons of capacity.
Piping length has been another ductless system challenge. Compressor limitations often restricted total piping runs to less than would be needed to adequately serve large and tall buildings, building without the expense of adding condenser/compressor units at system midpoints — increasing a ductless system’s cost or rendering it unfeasible from engineering, architectural or interior space standpoints. Advances in compressor technology have largely addressed these issues. Trane VRF variable refrigerant systems are available with high-speed compressors and unique electronic expansion valves that together can support total piping runs of up to 3,281 feet.
Natural bodies of water, ground loops and cooling towers all have been used to increase the efficiency of many different types of heating and cooling systems — and now, water-source technology is being integrated into ductless systems, too. If your application can take advantage of a water-source design, it also may be able to use a ductless system.
The energy savings gained by using water as a heat-exchange medium can be substantial — especially in a ductless system. Trane water-source ductless systems can deliver efficiencies of up to 30.1 IEER and 27.4 SCHE. Compared to traditional air-source systems, Trane water-source ductless systems operating at full load can deliver an average cooling EER that’s up to 26 percent higher — and an average heating coefficient of performance that’s up to 31 percent higher.
Your ductless application deserves a broad portfolio of choices
The greater the number of ductless systems that are available to meet your application’s unique needs, the more precisely those needs can be met — without compromise. Trane invites you to explore its expanded portfolio of ductless solutions and looks forward to helping make your building better … for life.