Investigation on 1-heptanol as an oxygenated additive with diesel fuel for compression-ignition engine applications: An approach in terms of energy, exergy, exergoeconomic, enviroeconomic, and sustainability analyses

Abstract

Studies on alternative and environmentally friendly fuels for compression-ignition engines continue intensively. In this work, energy, exergy, exergoeconomic, enviroeconomic, and sustainability analyses have been conducted by evaluating performance and emission values obtained by operating with different ratios of 1-heptanol/diesel blends (Hp0, Hp5, Hp10, and Hp20) as novel fuels under a constant speed (1500 rpm) with different engine loads (25%, 50%, 75%, and full load) in a single-cylinder, four-stroke, water-cooled, direct-injection, compression-ignition engine. In the test engine, energy and exergy efficiencies and losses, energetic and exergetic powers, irreversibility, and destruction of the exergy for the aforementioned fuel blends have been calculated and compared with pure diesel fuel. In the tests, the highest fuel consumption was determined as 0.221 kg/kWh in HP20 fuel at 100% load because 1-heptanol has lower calorific value than that of neat diesel fuel. The energy efficiency values in different loads of diesel engine for all fuel blends (Hp0-Hp20) have been calculated to be as between 14.46% and 40.72% along with the corresponding exergy efficiency values have been found to be as between 13.43% and 37.79%. By performing emission measurements, the highest CO2 emission cost has been calculated as 66.94 USD/year at a 100% load in Hp10 fuel according to the enviroeconomic analysis. In this present research, by implementing the exergoeconomic analysis, the highest engine output power cost at a load of 25% has been noted to be at 1.6 USD/MJ for Hp20 blend. Sustainability analysis has been determined according to the SI index, and the highest index was calculated to be 1.6 at a 100% load for Hp0 fuel.