Thermal efficiency

About: Thermal efficiency is a research topic. Over the lifetime, 20911 publications have been published within this topic receiving 302373 citations. The topic is also known as: thermodynamic efficiency & efficiency.

Effects of nano-copper additive on performance, combustion and emission characteristics of Calophyllum inophyllum biodiesel in CI engine

Abstract: Depletion of non-renewable energy sources are at elevated manner due to the rapid growth of industrialization and transportation sector in last few decades and leads to further energy demand. Biodiesels especially second-generation fuels from non-edible oil resources are alternate sources for replacement of diesel fuel in CI engines due to their considerable environmental benefits. In the present work, non-edible feedstock of Calophyllum inophyllum seed oil (tamanu oil) is used for biodiesel production. Transesterification method is used for preparation of biodiesel in the existence of methanol with NaOH as catalyst. The copper nanoparticles are synthesized by electrochemical method, and it is characterized by using X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). XRD and SEM results confirm the presence of copper nanoparticle and size of around 30 nm. This paper aims to investigate the effects of the copper additive nanoparticles with biodiesel blends on the engine performance, combustion and emission characteristics of single-cylinder direct-injection diesel engine and compared that with diesel fuel. The results showed that the addition of nano-additives enhances brake thermal efficiency and reduces specific fuel consumption compared to biodiesel blends but slightly lower than diesel. Combustion characteristics also are enhanced by improved oxidation reaction inside the combustion chamber which resulted in higher heat release rate. The emissions of HC, NOx and O2 are significantly reduced for nano-additive blends compared to diesel but increased CO2 emission was observed. It is noticed that higher CO2 emission and substantial reduction of unused O2 emissions from engine fueled with nano-additive are evident for enhanced oxidation and better combustion. Energy and exergy analysis of the diesel engine is carried out to estimate the effect of using nanoparticle additive with biodiesel.

Performance and emission characteristics of a diesel engine with varying injection pressure and fuelled with raw mahua oil (preheated and blends) and mahua oil methyl ester

Abstract: The present experimental investigation aims to depict the effect of varying injection opening pressure (IOP) using diesel-mahua oil (raw) blends as fuel on the characteristics of a small agricultural engine. The effect of preheated mahua oil and mahua oil methyl ester (MOME) as fuel on engine characteristics has also been investigated. Series of short-term tests were conducted on a single cylinder, 3.7 kW, water cooled, stationary diesel engine and performance and emission characteristics were determined using different diesel-mahua oil blends and also with varying IOP. Optimal IOP as well as blend ratio was determined for maximum efficiency and minimum emission values. Further, a novel pipe in pipe counter flow heat exchanger was designed and fabricated to arrange for preheating the raw mahua oil with exhaust gases of the engine. MOME was also prepared and tested as fuel in engine. Characterisation for major properties of all test fuels was conducted. Performance and emission characteristics of the diesel engine for raw mahua oil blends (unheated) at both rated and optimal IOP were compared with those of diesel, MOME and preheated raw mahua oil. At IOP of 226 bar, maximum brake thermal efficiency was obtained for M10, M20 and M30 blends. Significant reduction in carbon monoxide and hydrocarbon emission were observed. Nitrogen oxides emissions increased marginally. It was also observed that preheated mahua oil as fuel increases efficiency and reduces emissions. The use of M10 even at rated injection pressure and M20 and M30 at 226 bar results in minimum loss of efficiency and generates higher environmental benefits.

Effects of dust on the performance of thermal and photovoltaic flat plate collectors in Saudi Arabia: preliminary results

Abstract: The effect of dust accumulation on the surfaces of flat plate thermal and photovoltaic collectors has been studied and preliminary results are presented. One photovoltaic and two thermal panels were tested and the degradation in performance due to surface dust was determined. 10 refs.