Air conditioners (splits) were the first generation of direct expansion systems, consisting of two parts: an indoor unit and an outdoor unit connected together. After splits, multi-split systems were introduced to the market, allowing multiple indoor units to connect to a single outdoor unit.
However, multi-split systems had limitations such as:

• Limited number of indoor units connected to one outdoor unit (maximum 10 indoor units)
• Capacity limitation (maximum outdoor unit capacity 100,000 Btu/hr)
• Strict limits on piping length and height

Multi-split Systems

VRF systems are the next generation after multi-splits, introduced with technological advancements. These systems have outdoor units with a maximum capacity of up to 300,000 Btu/hr (varying by body type), and up to 1,200,000 Btu/hr by combining up to 4 outdoor units (varies by brand). VRF systems use inverter scroll compressors capable of connecting 64 or more indoor units to one outdoor unit (varies by brand).

Advantages of VRF Systems:

• Energy efficiency
• Quiet operation
• Simultaneous heating and cooling
• Use of inverter compressors
• Smart temperature control
• Minimal space installation
• Intelligent oil control technology
• Automatic fault diagnosis
• Use of R410A refrigerant
• Flexible design

Energy Efficiency:
By precise load control, minimizing energy loss, optimizing refrigerant distribution, and adjusting operating modes, VRF systems improve energy efficiency and save power consumption.

Quiet Operation:
VRF systems utilize advanced technology and flexible operation to minimize vibration and noise compared to split and multi-split systems. This makes VRF suitable for environments requiring peace and quiet.

Simultaneous Heating and Cooling:
VRF (Variable Refrigerant Flow) systems can provide both cooling and heating simultaneously. Indoor units, using separate compressors and refrigerant flow control, can cool some spaces while heating others.

Use of Inverter Compressors:
Inverter compressors in VRF systems can adjust their rotation speed according to system demand, unlike traditional compressors which operate at fixed speeds and cycle on/off to maintain temperature.

Smart Temperature Control:
VRF systems precisely control temperature in each building zone using intelligent control technology. Temperature sensors placed throughout the building measure conditions and send data to the VRF control panel to maintain desired temperatures automatically.

Minimal Space Installation:
Indoor units are installed on ceilings or walls and occupy minimal space without reducing usable room area.

Intelligent Oil Control Technology:
This technology optimizes compressor oil circulation by using pressure and temperature sensors and system controllers, preventing oil accumulation in cold parts and enhancing compressor efficiency and lifespan. This reduces maintenance costs and improves system performance.

Automatic Fault Diagnosis:
Equipped with Line Error technology, VRF systems automatically monitor and diagnose faults.

R410A Refrigerant:
R410A is a refrigerant blend of R32 and R125 gases in a 50/50 ratio, featuring a lower boiling point and higher efficiency than other refrigerants. It is environmentally friendly and does not damage the ozone layer.

Flexible Design:
One outdoor unit can simultaneously connect to multiple indoor units with various capacities.

Source:
“VRF HVAC Systems” by Engineer Seyed Mehrdad Rostamabadi, Shafaf Publishing

Suggested Article: “Types of Indoor and Outdoor VRF Systems”