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How Does Ductless Air Conditioning Work

Ductless split systems provide targeted heating and cooling comfort when conventional central HVAC equipment is too costly or impractical to install. Widely adopted in Europe and Southeast Asia, ductless technology continues to gain popularity in the U.S. as consumers and businesses look for cost-effective alternatives to window units, PTACs (packaged terminal air conditioners) and inefficient ducted systems.

Basic Components of a Ductless System

So, how does ductless air conditioning work? In many respects, a ductless mini split operates in a similar manner to its ducted counterpart.

In the refrigeration cycle, low-pressure gas is transformed into high-pressure gas by the action of a compressor. The heat is dissipated into the outdoors by the action of a forced air fan. The refrigerant then becomes a high-pressure liquid, and it is again changed into a low-pressure liquid by a metering device at the evaporator coil. Heat energy from the indoor air is absorbed by the refrigerant, and the resulting cooler air is pushed into the living area by the internal blower. The resulting low-pressure gas is moved through the suction line back to compressor, and the cycle is repeated again.

There are two main elements in a ductless split system installation:

Outdoor Unit

The outdoor condensing unit houses three primary components including:

  • The Compressor: The compressor is the heart of any air conditioning system. It is also the most expensive individual part. The device condenses low-pressure gas into high-pressure gas, so the thermal heat transfer process is completed more efficiently.
  • Condensing Coil: A lattice-like structure comprised of numerous aluminum fins, the condensing coil cycles hot refrigerant and accommodates its conversion from a high-pressure gas to a high-pressure liquid.
  • The Fan: The fan draws air through the condensing coil and helps dissipate the stored heat energy into the outdoor environment.

Indoor Unit

How do ductless air conditioners work?

It is important to recognize the distinct advantages of spilt system indoor fan coil units. Conventional central air conditioners employ a single air handler, blower and evaporator coil, which is usually installed in a garage or equipment closet. A complex air distribution network provides an avenue for the delivery of conditioned air into each room of the building from a single point of origin. Unfortunately, ductwork is often inefficient, restrictive, dirty, leaky and noisy.

Ductless indoor units include a fan and evaporator coil in the same enclosure. Each unit provides point of use air conditioning wherever it is installed. Stylish cabinets are available in wall mount, duct mount and ceiling cassette varieties.

Whether used in single or multiple zone configurations, the indoor units can be strategically positioned to heat and cool one room or an entire building. The versatility and convenience of ductless technology completely eliminates the need for inefficient ductwork.

When comparing ductless ac vs. central ac vs. window unit, ductless split systems are quieter, more efficient and offer greater levels of comfort.

Mini-Split versus Multi-Split

In multi-room applications, does ductless AC work?

In fact, ductless air conditioners are an excellent choice for both single and multi-zone areas. Systems can be installed in a variety of different configurations based on the following two platforms:

Mini-Split: A mini split includes a single indoor fan coil and outdoor condenser. This combination is especially effective for cooling an individual room that has limited load requirements. If there is sufficient space to set multiple condensing units outdoors, several systems can be used in tandem to provide cooling for an entire building.

This type of installation provides a separate temperature control for each unit. If there is a malfunction in one system, the rest will continue to provide conditioned air to the unaffected areas.

Multi-Split: A multi-split system employs one condensing unit that is connected to several indoor air handlers. In this configuration, an indoor unit is selected and equipped with a thermostat. When there is a call for cooling, all of the units are activated simultaneously. This configuration is cost effective but should only be used in buildings where each room has a similar cooling load.

For true zoning in a multi-split application, a single condensing unit must be equipped with separate compressor circuits that are piped to each individual air handler. Every zone is controlled by a different thermostat, so the occupants can tailor the temperature to their individual preference. A Mitsubishi air conditioner designed for multi-split operation can include up to eight different zones.

Ductless Heat Pump How it Works

In the cooling mode, a ductless heat pump operates in essentially the same way as an air conditioner. The inclusion of a reversing valve allows the refrigerant to flow in either direction, which provides both heating and cooling from a single ductless system.

When considering the installation of a ductless heat pump, it is important to understand the relationship between heating efficiency and the outdoor ambient temperature. In general, a heat pump operates most effectively in mild climates that rarely reach the freezing point. An electric heat strip can be installed to provide supplemental heat when necessary.

Where Ductless is needed

Ductless air conditioners and heat pumps offer exceptional flexibility and can be modified to fit numerous applications. In addition to existing buildings, mini splits are appearing more frequently in new construction where the low profile of ductless equipment is very compatible with modern architectural design.

An Air Conditioner Small Enough For:

  • Server Rooms
  • Condos
  • Basements
  • Garages
  • Attics
  • Buildings Requiring Supplemental Cooling

An Air Conditioner Quiet Enough For:

  • Hospitals
  • Churches
  • Bedrooms
  • Recording Studios
  • Meeting Rooms

An Air Conditioner Powerful Enough For:

  • Office Buildings
  • Multi-Tenant Buildings
  • High Rise Buildings
  • Hotels
  • Data Centers

High Efficiency Perfect for Everyone

Ductless split systems offer exceptional versatility, low noise and enhanced levels of comfort. Through the use of exclusive inverter technology, ductless air conditioners have the highest SEER ratings in the industry.

Many consumers ask, “How much does ductless AC cost?” By eliminating the need for an air distribution network, a ductless air conditioner saves substantially on labor and installation costs. Mitsubishi contractors invite you to explore the many benefits that an efficient ductless split system can provide.