In order to exhaust remained hydrogen gas in the stack, one has to consider two aspects: safety in diluting hydrogen gas into air to control the concentration of hydrogen gas; comfort in modulating released gas to prevent harsh noise.

In this paper, the development processes of a hydrogen exhaust system in terms of dilution efficiency and its noise reduction have been defined both computationally and empirically. The diluting-efficiency of hydrogen gas has been investigated using a commercial CFD program and compared to measured results thus obtained from a prototype hydrogen exhaust system. Moreover, noise characteristics of hydrogen exhaust system has been also assessed according to the optimized design process: computational prediction and its empirical validation.

The design process for the developments of a conventional exhaust system has been expanded to cover the dilution efficiency of hydrogen gas. It must be emphasized that such a process provides a set of basis for further developments of hydrogen exhaust system in the future.