Indoor space risk assessment based on Co-analysis strategy in split room air conditioning

Abstract

The use of environmentally friendly hydrocarbon refrigerants in air conditioning systems is being promoted worldwide as a proactive measure to combat global warming and ozone depletion. A comprehensive analysis of hydrocarbon refrigerant leakage and the resulting fire risk is essential for split room air conditioning (SRAC) systems. The study presents a novel Co-analysis strategy that integrates the operation of SRAC systems with the assessment of indoor space fire risk. Experiments involving the leakage and diffusion of R-290 in SRAC system have been conducted to substantiate the validity of the Co-analysis strategy. This model is used to analyze the dynamic parameters of leakage and distribution patterns of hazardous areas within the SRAC indoor unit. The study considers various leakage hole sizes (1 mm, 2 mm, 3 mm) under both cooling and heating operating modes. The results show the leaking refrigerant flow rate presents different attenuation types under cooling and heating modes. When the leakage hole diameter is less than 2 mm in the cooling mode, the concentration of R-290 in the space is below 50 % lower flammable limit. The comprehensive fire risk probability of the R-290 indoor unit is 1.0 × 10−11∼5.0 × 10−10 for the cooling model and 1.0 × 10−11∼9.0 × 10−10 for the heating model. Effective methodologies for mitigating risks and optimizing the system are also proposed. Based on the Co-analysis strategy, this study presents a scientifically grounded assessment of the fire risk associated with air conditioning uses flammable refrigerants inside buildings. The strategy aims to enhance building safety.