Preliminary Experimental Analysis of a CHP Hydromethane System

The aim of this paper is to present the preliminary experimental analysis results carried out on the commercial internal combustion engine set in a CHP (combined heat and power) mode, fueled by renewable hydrogen and methane mixtures. The hydrogen is produced by an alkaline electrolyser fed by a 5.8 kWp grid connected PV (photovoltaic) plant. The acceptance test conducted with hydrogen percentages ranging from 0%-10% has been carried out at partial load: 45 kWel instead of the full power of 60 kWel. In order to evaluate the CHP energy consumption and environmental performance (NOx and CO), the analysis was conducted for 240 h, using a portable flue gas analyser and two mass flow meters for hydrogen and methane. Without engine parameters optimization—relative equivalence ratio (λ) and spark advance—increasing hydrogen addition rate, a slight enhancement in electrical efficiency occurs. Furthermore, due to the engine control system and lower blends LHV (lower heating value), the methane consumption decreases disproportionately to the hydrogen amount in the mixture. Finally, referring to standard operating condition, the environmental results show that using enrichment of 10%, running the engine with 18 degrees spark advance and λ of 1.4, CO and NOx emissions are reduced by 6.3% and 27% respectively.