Exergy and Energy Analyses of the Spirulina Microalgae Blends in a Direct Injection Engine at Variable Engine Loads

This article explores the exergy analysis of the diesel engine with the selected Spirulina microalgae bio-oil (SMBO) biodiesel. The adaptability of the biofuels as an efficient replacement to the fossil fuel has to be tested and proved. To estimate the overall efficiency of the engine with the biofuel blends, it is essential to find out the energy conversion capability of the engine. Different fuel blends were taken as B0 (100% diesel), B10 (10% SMBO + 90% diesel), B20 (20% SMBO + 80% diesel), and B30 (30% SMBO + 70% diesel). All experimental tests were conducted in a naturally aspirated directly injected engine. The brake power (BP), heat release rate (HRR), exergy destruction, ideal efficiency, actual efficiency, exergy rate and energy rate of the fuel, as well as exhaust were measured for all fuel blends. All tests were conducted at different rpm values from 0 to 3000 rpm with 500 rpm interval and also at different loads such as 0%, 25%, 50%, 75%, and 100% load. The loss of exergy of fuel and thermal was on the rise and noticed in B0, B10, B20, and B30, while the HRR and loss of exergy rate were found in exhaust as more decreasing one in B10, B20, and B30 fuel blends than B0 (pure diesel).

Automated summary

This article examines the exergy analysis of a diesel engine using Spirulina microalgae bio-oil biodiesel. The study shows that biofuels can improve the engine efficiency compared to pure diesel.