H2-BusAC: Low Carbon Hydrogen Bus Air Conditioning System with Compact Hydrogen Storage and Hydrogen Fuel Cell

Globally, the development of hydrogen fuel cell (H2FC) vehicles has attracted more and more attention to replacing the conventional gasoline fuel vehicles. These are attributed to a number of important advantages from the H2FC ones including low carbon emissions, no air pollution and sufficient energy resources. They are more suitable for transports in populated areas such as buses in cities, where less transport air pollution and limited carbon emissions are strictly demanded. Conventionally, an H2FC bus utilises high pressure (about 350 bar) tanks to store hydrogen on board. This leads to safety concerns for the passengers on board and takes relatively larger space. In addition, to fill the high pressure hydrogen tanks on board, even higher hydrogen pressure (about 500 bar) is needed at a specially designed hydrogen fuelling station which can consume excessive power. On the other hand, an air conditioning system in an H2FC bus is necessarily installed to maintain the comfortable condition of the passenger compartment. Normally, the air conditioning system uses a vapour compression cycle and is driven by electricity. The power consumption in the air conditioning system requires extra electricity from the fuel cell (FC) power generation and thus reduces significantly the maximum bus driving range. Subsequently, a H2FC bus with compact and secured hydrogen storage and a highly efficient air conditioning system is immediately desired. In this feasibility study, a novel hydrogen storage and air conditioning system for the H2FC bus (H2-BusAC) will be designed, simulated, optimised and specified for prototype development in the next stage. Instead of using high pressure tanks to store hydrogen on board, a specially designed hydrogen reactor heat exchanger will be developed to store the hydrogen with moderate pressure. This can diminish the safety concerns for the high pressure hydrogen storage on board. Meanwhile, the charging pressure of hydrogen at a hydrogen fuelling station and corresponding compression pressure and power are therefore significantly reduced. On the road, the hydrogen from the reactor heat exchanger releases to a fuel cell on board to generate power and drive the bus. In the meantime, the reactor absorbs heat from the passenger compartment to produce cooling during the summer period when cooling is demanded. During the winter period, space heating is satisfied by the waste heat from the fuel cell power generation process. Some essential design and operating conditions for conventional hydrogen FC buses will be obtained from industrial partners.