Analysis of Operational Parameters and Emissions in a Domestic Natural Gas Heating Appliance with Hydrogen Blending

The weather-dependent nature of renewable energy production has led to periodic overproduction, making hydrogen production a practical solution for storing excess energy. In addition to conventional storage methods, such as physical tanks or chemical bonding, using the existing natural gas network as a storage medium has also proven to be effective. Households can play a role in this process as well. The purpose of these experiments is to evaluate the parameters of a household heating device currently in use but not initially designed for hydrogen operation. The appliance used in the tests has a closed combustion chamber with a natural draft induced by a density difference, which is a common type. The tests were conducted at nominal load with a mix of 0–40 V/V% hydrogen and natural gas; no flashbacks or other issues occurred. As the hydrogen ratio increased from 0 to 40 V/V%, the input heat decreased from 3.9 kW to 3.4 kW. The NOx concentration in the flue gas dropped from 26.2 ppm to 14.2 ppm, and the CO2 content decreased from 4.5 V/V% to 3.4 V/V%. However, the CO con centration slightly increased from 40.0 ppm to 44.1 ppm. Despite these changes, efficiency remained stable, fluctuating between 86.9% and 87.0%. The internal flame cone height was 3.27 mm when using natural gas, but reduced sharply to just 0.38 mm when using 62 V/V% hydrogen. In addition to the fact that the article examines a group of devices that has been rarely investigated but is also widely distributed, it also provides valuable experience for other experiments, since the experiments were carried out with a higher hydrogen ratio compared to previous works.