Study on reproducibility of exhaust diffusion properties of gas water heaters in apartment complexes

Abstract

Gas water heaters in Japan are generally in shared corridors. However, there are restrictions on the installation location and the shape of the corridor to avoid the stagnation of exhaust gas in the corridor and its flow into the rooms through the external air supply opening. These installation standards limit building planning and require further mitigation. Although experiments using full-scale models have been conducted, it is still difficult to consider all possibilities as the shared corridors can be of many shapes. The relaxation of standards should be studied through simulations using computational fluid dynamics (CFD). First, the target data for reproducing the exhaust properties in the CFD analysis are collected via actual measurement. Subsequently, the exhaust diffusion properties of gas water heaters are reproduced by simulation using CFD analysis based on the measured data. Reproducibility is improved by changing the location of the outlet boundary condition in gas water heaters. Finally, the reproducibility of the exhaust diffusion properties is examined for the gas water heater installed in the shared corridor. Comparing the experimental and simulation results, confirms the reproducibility of the concentrations at the exhaust trajectories and air supply outlets.