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 CO 2 content decreased from 4.5 V/V% to 3.4 V/V%. However, the CO concentration 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. • Mixing hydrogen into natural gas is currently a topical issue for energetic reasons. • This solution helps the problem of hydrogen storage. • Combustion tests on household appliances is essential before the final solutions. • Equipment tested is a widespread one in Central and Eastern Europe. • Tests provide important data for global regulations in case of hydrogen mixing.