VRF(Variable Refrigerant Flow) system working principle

The VRF(Variable Refrigerant Flow) system, known as “one-to-many,” connects multiple indoor units to one outdoor unit. It exchanges heat outdoors using air-cooled heat exchange. It adjusts indoor temperatures through direct evaporation. This system uses refrigerant as the primary transmission medium. The outdoor unit includes a heat exchanger, compressor, and other components. The indoor unit contains a direct evaporative heat exchanger and a fan.

The VRF（Variable Refrigerant Flow） system offers high efficiency and energy savings. It operates stably and supports independent control. It precisely controls temperatures based on room needs. By adjusting refrigerant flow, it enables variable compressor capacity. This adjustment further improves energy efficiency.

The market mainly offers the following vrf technologies:

Variable frequency VRF technology adjusts compressor power based on indoor load changes. It changes input frequency to control compressor speed. This technology ensures linear cooling capacity control. The electronic expansion valve precisely controls indoor temperature.

Digital scroll vrf technology features “axial flexibility.” This allows the fixed scroll plate to move slightly axially. It ensures the scroll plate stays in the best state. This technology maintains efficient operation under any conditions.

8 Key Steps for VRF(Variable Refrigerant Flow) Installation

• Place the indoor unit at least 1 cm from the ceiling. Use tools to level the unit and avoid resonance.
• Weld copper pipes and branch pipes using nitrogen-filled welding. This prevents carbon deposition and ensures system cleanliness.
• Perform a nitrogen pressure test after welding. Maintain pressure for 24 hours to check for leaks. R410A systems require 40 kg pressure; R22 systems need 20 kg.
• Install the condensate pipe with at least a 1% slope. Ensure water flows smoothly and discharges outside or to a drain.
• Ensure sufficient space at the outdoor fan outlet. Leave 50 cm in front and 15 cm at the back. Install shock absorbers to reduce vibrations.
• Vacuum the system before filling refrigerant. This removes air and moisture, preventing ice crystal formation and equipment damage.
• Release the refrigerant from the outdoor unit. Test pressure and add refrigerant as needed until the system operates optimally.
• Match the return air vent with the indoor unit vent. Leave room for thermal expansion and avoid placing outlets near light strips.

Common Protection Mechanisms of VRF(Variable Refrigerant Flow) Systems

• High-pressure protection shuts down the system when pressure is too high. This protects the compressor from damage caused by rising exhaust temperatures.
• Anti-freeze protection monitors the evaporator temperature. When temperatures drop too low, it stops the compressor but keeps the fan running to prevent freezing.
• Low-pressure protection shuts down the system when suction pressure is insufficient. This prevents frost on the evaporator and maintains energy efficiency.
• Exhaust pipe high-temperature protection turns off the compressor and fan when exhaust temperatures are too high. This avoids damage from excessive heat.
• Overcurrent protection activates when the current exceeds the limit. This mechanism prevents electrical faults from harming the system.
• Communication failure stops related functions if indoor and outdoor units lose communication. This avoids further damage to the system.
• Sensor failure detects abnormal temperature sensors. The system diagnoses issues by measuring resistance and protects the equipment.
• Voltage protection monitors power grid abnormalities. It prevents equipment damage from overvoltage or undervoltage.
• Reverse phase protection stops the compressor from starting when it detects a power phase sequence error. This prevents damage to the equipment.