Energy-efficient refrigeration cycle strategies for capacity improvement and humidity control in VRF systems

Abstract The growing demand for energy-efficient and environmentally sustainable HVAC solutions in residential buildings has driven the adoption of Variable Refrigerant Flow (VRF) systems. VRF technology, typically using R410A as the working fluid, provides simultaneous heating and cooling with enhanced part-load efficiency and greater operational flexibility than conventional central air conditioning systems. This study aims to optimize the refrigeration cycle of a VRF high wall indoor unit to improve cooling capacity and dehumidification performance. A combination of experimental and analytical methods was employed to evaluate system behavior under varying ambient temperatures and load conditions. Special emphasis was placed on assessing resistance to surface condensate formation (sweating), which is prevalent in high-humidity environments. Results indicate that specific cycle enhancements can significantly increase capacity utilization and improve control over dew point conditions. These improvements suggest that optimized VRF systems can better meet thermal comfort and moisture regulation requirements, particularly in tropical and sub-tropical climates where both energy efficiency and humidity control are critical.