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•
16 Jan 2007
TL;DR: In this paper, an energy conversion system including a high efficiency absorption heat pump cycle is disclosed using a high pressure stage, a supercritical cooling stage, and a mechanical energy extraction stage to provide a non-toxic combined heat, cooling, and energy system.
Abstract: An energy conversion system including a high efficiency absorption heat pump cycle is disclosed using a high pressure stage, a supercritical cooling stage, and a mechanical energy extraction stage to provide a non-toxic combined heat, cooling, and energy system. Using the preferred carbon dioxide gas with partially miscible absorber fluids, including the preferred ionic liquids as the working fluid in the system, the present invention desorbs the CO.sub.2 from an absorbent and cools the gas in the supercritical state to deliver heat. The cooled CO.sub.2 gas is then expanded, preferably through an expansion device transforming the expansion energy into mechanical energy thereby providing cooling, heating temperature lift and electrical energy, and is returned to an absorber for further cycling. Strategic use of heat exchangers, preferably microchannel heat exchangers comprised of nanoscale powders and thermal-hydraulic compressor / pump can further increase the efficiency and performance of the system.
89 citations
TL;DR: In this paper, the performance of a low-temperature solar recuperative Rankine cycle system using working fluid R245fa was investigated in Tianjin, China, where the working fluid is typically preheated; this process is simulated using an electric tracing ribbon.
89 citations
TL;DR: In this article, a review of the factors that induce backfire in hydrogen-injected internal combustion engines is presented, including improper intake valve timing and fuel injection timing, high fuel-air equivalence ratios, and improper hydrogen distribution around intake valve seats.
89 citations
TL;DR: In this article, a new parameter called coefficient of energy gain (CEG) has been introduced that provides information on the energy gained from the process and elaborates the importance of optimizing the sample residence time in the reactor.
89 citations
TL;DR: In this article, an aluminum-alloy flatbox type PV/T collector prototype was constructed and tested in Hong Kong, and the test results indicate that a high combined thermal and electrical efficiency can be achieved.
Abstract: Photovoltaic-thermal (PV/T) systems integrate photovoltaic and solar thermal technologies into one single system with dual production of electricity and heat energy. A typical arrangement is the direct attachment of PV modules onto a solar thermal collector surface. For a given collector surface area, the overall system energy performance is expected higher than the conventional "side-by-side" PV and solar thermal systems. In the development of PV/T collector technology using water as the coolant, the most common design follows the sheet-and-tube thermal absorber concept. Fin performance of the thermal absorber has been identified as one important factor that affects much the overall energy performance of the collector. Accordingly, an aluminum-alloy flat-box type PV/T collector prototype was constructed and tested in Hong Kong. Our test results indicate that a high combined thermal and electrical efficiency can be achieved. The primary-energy-saving efficiency for daily exposure approaches 65% at zero reduced temperature operation. With a simple and handy design, the product is considered to be very suitable for domestic application.
88 citations