Preliminary Experimental Analysis of R32 Refrigerant Thermal Response in a Residential Air Conditioner

Department of Mechanical and Industrial Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika No.2, Yogyakarta, Indonesia

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Abstract

Air conditioning systems are widely used in residential buildings, increasing the need for accurate and representative performance evaluation methods. However, conventional testing approaches are often limited in capturing the dynamic thermal behavior of residential air conditioning systems under varying indoor conditions. This study presents the development of a 2 × 2 × 2.5 m experimental chamber for controlled performance evaluation of a residential air conditioning system with a 0.5 PK compressor. The chamber enables real-time monitoring of indoor air temperature, supply air temperature, and refrigerant thermal characteristics. Experiments were conducted at room temperature setpoints of 20°C, 25°C, and variable conditions of 26°C–24°C-22°C–26°C. The results show that the system successfully achieved all setpoints, although lower temperatures required longer stabilization times due to higher cooling loads. Significant transient behavior was observed during startup, including rapid supply air cooling and increased compressor outlet temperature. In addition, the coefficient of performance (COP) increased during stable operating conditions, indicating improved cooling efficiency. The developed chamber provides a reliable platform for controlled residential air conditioning performance evaluation and future HVAC thermal monitoring studies.