Effect of Compressor Speed on Cooling-Heating Energy Performance with Climate-Friendly Refrigerants

Abstract

The sustainability of the Heating, Ventilation, and Air Conditioning (HVAC) system focuses on reducing energy consumption, improving efficiency, minimizing environmental impact, and improving indoor air quality while maintaining comfort. Sustainable HVAC practices are critical in combating climate change and creating energy-efficient systems. High-efficiency components, such as inverter technology and variable-speed compressors, will adjust cooling output to actual demand, unlike fixed-speed compressors that operate at full capacity and use more energy. A Variable Refrigerant Flow (VRF) system is a type of HVAC technology commonly used in commercial buildings, hotels, residential complexes, and schools, where comfort and efficiency are priorities. By modulating refrigerant flow, VRF systems consume less energy than conventional systems, making them highly efficient, adaptable, and suitable for various building types. The current study compares climate-friendly refrigerants R1234yf and R515B under different compressor frequencies (35, 40, 45, and 50 Hz). The experiment tests were carried out at water-glycol heat source temperatures of 12°C to 6°C, and water heat sink temperatures of 45°C to 50°C (inlet and outlet temperatures, respectively). The degree of subcooling and superheating was maintained at 5°C and 10°C, respectively. R1234yf showed the highest refrigerant mass flow rate for the range of test frequencies, which increased the compressor power consumption. Contrarily, R515B presented the highest system coefficient of performance (COP), highlighting it as an energy-efficient and safe alternative refrigerant in buildings.

Keywords: VRF, compressor frequency, global warming potential, R515B, energy efficiency