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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Patent•
26 May 1992
TL;DR: In this paper, a hybrid-propulsion car system with one axle driven by an internal combustion engine and another axis driven by a electric motor is described, where the waste heat of the engine cooling fluid is exchanged with an evaporative fluid in a closed circuit.
Abstract: A hybrid-propulsion car system having one axle driven by an internal combustion engine and another axis driven by an electric motor. The waste heat of the internal combustion engine is absorbed by the engine cooling fluid, and is then heat exchanged with an evaporative fluid in a closed circuit. The evaporative fluid is vaporized by the heat of the engine cooling fluid in order to drive an expander which in turn drives an electric generator. The electric generator supplies current to a storage battery and to the electric motor.
173 citations
TL;DR: In this article, it was shown that open-circuit operation is a reversible process and leads to the Carnot efficiency, if one defines the efficiency in the way that is usual in the theory of thermodynamic engines.
Abstract: An infinite stack ofp—n junctions with smoothly varying bandgap from ∞ to 0 is considered. AnI —V characteristic is derived, which is more correct than the classical exponential characteristic. It is shown that open-circuit operation is a reversible process and leads to the Carnot efficiency, if one defines the efficiency in the way that is usual in the theory of thermodynamic engines. If instead one uses the definition of efficiency usual in photovoltaics, open-circuit mode gives rise to zero efficiency. Then operation at maximum efficiency equals operation at maximum power and is not reversible.
173 citations
TL;DR: In this article, the effect of rotation on rotor blade coolant passage was investigated with rib turbulators and impinging jets, and the results were compared to experimental data using the RANS method with various turbulence models such as k-e, and second-moment closure models.
Abstract: Gas turbines are used extensively for aircraft propulsion,
land-based power generation, and industrial applications.
Developments in turbine cooling technology play a critical
role in increasing the thermal efficiency and power output of
advanced gas turbines. Gas turbine blades are cooled internally
by passing the coolant through several rib-enhanced
serpentine passages to remove heat conducted from the outside
surface. External cooling of turbine blades by film cooling
is achieved by injecting relatively cooler air from the
internal coolant passages out of the blade surface in order
to form a protective layer between the blade surface and
hot gas-path flow. For internal cooling, this presentation focuses
on the effect of rotation on rotor blade coolant passage
heat transfer with rib turbulators and impinging jets. The
computational flow and heat transfer results are also presented
and compared to experimental data using the RANS
method with various turbulence models such as k-e, and
second-moment closure models. This presentation includes
unsteady high free-stream turbulence effects on film cooling
performance with a discussion of detailed heat transfer coef-
ficient and film-cooling effectiveness distributions for standard
and shaped film-hole geometry using the newly developed
transient liquid crystal image method.
172 citations
TL;DR: In this paper, a novel photovoltaic solar assisted heat pump (PV-SAHP) system has been proposed and performance tests with a range of condenser supply water temperature were conducted on an experimental rig.
171 citations
TL;DR: In this paper, a mathematical model based on the finite-time thermodynamics has been developed so that the output power and thermal efficiency and the rate of entropy generation of the solar Stirling system with finite rate of heat transfer, regenerative heat loss, conductive thermal bridging loss and finite regeneration process time are obtained.
171 citations