A combustion system with surface-less heat energy exchange for efficient heat energy capture and lower pollutant emission, comprising: a first line feeding an oxygen-rich reactive; a second line feeding a hydrogen fuel; a vessel containing feed-water, a combustion enclosure without a bottom wall submersed into the feed water contained in a vessel, the combustion enclosure configured to receive the feed from each of the first and second line and combust a mixture of the two feeds in a pocket formed between an inner top and side walls of the combustion enclosure and a top surface of the feed-water contained in the vessel; and the combustion within the pocket yielding a high temperature and pressure combustion product and by-product directly into the feed-water of the vessel.