Topic
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.
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TL;DR: In this article, the authors presented a generalized irreversible heat engine model that incorporates several internal irreversibilities, such as heat leak, friction, turbulence etc., and derived the relation between optimal power output and efficiency based on a generalized heat transfer law.
Abstract: In a classical endoreversible Carnot engine model, irreversibility in the form of heat resistance between the reversible Carnot cycle and its heat reservoirs is taken into account. This paper presents a generalized irreversible Carnot engine model that incorporates several internal irreversibilities, such as heat leak, friction, turbulence etc. These added irreversibilities are characterized by a constant parameter and a constant coefficient. The relation between optimal power output and efficiency is derived based on a generalized heat transfer law . The effect of heat leakage, internal irreversibility and heat transfer law on the optimal performance of the generalized irreversible heat engine is investigated.
117 citations
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TL;DR: In this article, a dimensionless "figure of merit" combining the Jakob number, condensing temperature, and evaporation temperature is proposed for quantitatively screening working fluid as far as thermal efficiency is concerned.
117 citations
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TL;DR: In this paper, a latent heat storage module was constructed, consisting of 45 cylindrical capsules fixed vertically in 15 rows, made of 0.335m long copper tubes having external diameters of 31.8 mm, were fixed in an insulated rectangular duct.
Abstract: A latent heat storage module was constructed, consisting of 45 cylindrical capsules fixed vertically in 15 rows. The capsules, made of 0.335-m long copper tubes having external diameters of 31.8 mm, were fixed in an insulated rectangular duct. Three commercial waxes having melting temperatures of 44°C, 53°C, and 64°C were selected. Each of the three sets of 15 tubes was filled with different wax. For comparison purposes, experiments were also done with a single commercial wax, having a melting temperature of 53°C, in all the tubes. During heat charge, hot air flowed across the capsules such that the melting temperature of the waxes decreased in the flow direction. Air flow direction was reversed during heat discharge. Experimental measurements showed some improvement in the heat transfer rates during both heat charge and discharge when three types of PCM’s were used. There was no improvement in the heat transfer rate during the sensible heat storage period, while a maximum increase of 15 percent was observed during the latent heat period. Theoretical predictions for the performance of the storage module were in reasonable agreement with the experimental measurements.
117 citations
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TL;DR: In this paper, the energy efficiency of an updated ORC (organic Rankine cycle) was investigated at different heat source temperatures of about 100, 90, 80, and 70°C.
117 citations
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TL;DR: In this article, the performance of a small-scale two-staged gasification system is reported, where wood chips are gasified with a fixed bed gasifier and then tar in the produced gas is reformed in a non-catalytic reformer, finally the production gas is used to generate electricity.
117 citations