Design and Construction of an On-Demand, Submerged Combustion, Direct-Contact Water Heater operating on Hydrogen for use in the Agricultural Sector

Transitioning to a green hydrogen economy requires end-use applications. Some water heating units that currently operate on propane or natural gas may be able to safely operate on hydrogen-enriched natural gas mixtures (HENG) with up to 20–30% hydrogen with no modification. Higher amounts of hydrogen may be possible with a moderate level of retrofitting. However, units designed specifically to operate on 100% hydrogen are currently not available.

This project aims to design, construct, and demonstrate the operation a novel prototype water heater specifically for hydrogen as the fuel. Conventional on-demand gas-fired water heaters avoid the need to store hot water. These are referred to as tankless water heaters. On opening a hot water faucet cold water enters the unit and passes through a tubular heat exchanger that is heated by a gas flame. These units are very efficient. The use of hydrogen as a fuel opens the possibility for even better efficiency by removing the tubular heat exchanger and using a hydrogen flame such that the products of combustion, which are essentially water vapour, interact directly with the flow of water rapidly heating it.

The work would be undertaken by an MEng graduate student and an undergraduate co-op student under the direct supervision of Dr. Michael J. Pegg, P. Eng. The operation and efficiency of the prototype unit would be compared to that of a conventional gas-fired tankless water heater. As part of an ongoing project to test and certify natural gas appliances operating on HENG the unit would be evaluated for certification operating on 100% hydrogen. Having hydrogen-ready certified appliances available when widespread use of green hydrogen becomes available would position Nova Scotia at the forefront of clean energy utilization.


Principal Investigator: Michael Pegg, Dalhousie University

September 1, 2023 – September 30, 2024