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 present a thermodynamic modeling of hybrid photovoltaic-thermal (PV/T) solar systems using Simulink/Matlab.
103 citations
TL;DR: An over-expansion cycle (Atkinson or Miller) engine is the most suitable for hybrid vehicles because it can realize a larger expansion ratio and thus, a higher thermal efficiency while maintaining a normal effective compression ratio to avoid the knock.
103 citations
TL;DR: In this article, a dual loop waste heat recovery power generation system that comprises an upper trilateral cycle and a lower organic Rankine cycle, in which discharged exhaust gas heat is recovered and reused for propulsion power, was theoretically applied to an internal combustion engine for propulsion in a 6800 TEU container ship.
103 citations
TL;DR: In this article, real-gas effects occurring in subcritical and supercritical organic Rankine cycle nozzles have been investigated using two-dimensional Euler simulations of an existing axial ORS stator nozzle.
Abstract: Organic Rankine cycle turbogenerators are a viable option as stationary energy converters for external heat sources, in the low power range (from a few kW up to a few MW). The fluid-dynamic design of organic Rankine cycle turbines can benefit from computational fluid dynamics tools which are capable of properly taking into account real-gas effects occurring in the turbine, which typically expands in the nonideal-gas thermodynamic region. In addition, the potential efficiency increase offered by supercritical organic Rankine cycles, which entails even stronger real-gas effects, has not yet been exploited in current practice. In this paper, real-gas effects occurring in subcritical and supercritical organic Rankine cycle nozzles have been investigated. Two-dimensional Euler simulations of an existing axial organic Rankine cycle stator nozzle are carried out using a computational fluid dynamics code, which is linked to an accurate thermodynamic model for the working fluid (octamethyltrisiloxane C 8 H 28 O 2 Si 3 ). The cases analyzed include the expansions starting from actual subcritical conditions, that is, the design point and part-load operation, and three expansions starting from supercritical conditions. Results of the simulations of the existing nozzle for current operating conditions can be used to refine its design. Moreover, the simulations of the nozzle expansions starting from supercritical conditions show that a nozzle geometry with a much higher exit-to-throat area ratio is required to obtain an efficient expansion. Other peculiar characteristics of supercritical expansions such as low sound speed and velocity, high density, and mass flow rate, are discussed.
103 citations
TL;DR: In this article, the thermal performance of a photovoltaic/thermal system, integrated with phase change materials in porous medium, was investigated, and the results showed that the exergy efficiency of the PV/T module with metal foam filled with PCM was 16.7%.
102 citations