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.

Thermal management using synthetic jet ejectors

Abstract: The utility of a synthetic jet ejector for thermal management at low flow rates is discussed. A synthetic jet ejector typically consists of a primary "zero-mass-flux" unsteady jet driving a secondary airflow through a low profile, high aspect ratio channel. A simple configuration of a nominally two-dimensional jet ejector in a rectangular channel is used to investigate the effects of channel width on the induced flow rate, power dissipated, heat transfer coefficient and thermal efficiency. An active heat sink for high power microprocessors is developed using the jet ejector concept and its performance is discussed.

Co-combustion - A summary of technology

Abstract: Co-combustion of biomass or waste together with a base fuel in a boiler is a simple and economically suitable way to replace fossil fuels by biomass and to utilise waste. Co-combustion in a high-efficiency power station means utilisation of biomass and waste with a higher thermal efficiency than what otherwise had been possible. Due to transport limitations, the additional fuel will only supply a minor part (less than a few hundreds MWfuel) of the energy in a plant. There are several options: co-combustion with coal in pulverised or fluidised bed boilers, combustion on added grates inserted in pulverised coal boilers, combustors for added fuel coupled in parallel to the steam circuit of a power plant, external gas producers delivering its gas to replace an oil, gas or pulverised fuel burner. Furthermore biomass can be used for reburning in order to reduce NO emissions or for after burning to reduce N2O emissions in fluidised bed boilers. Combination of fuels can give rise to positive or negative synergy effects, of which the best known are the interactions between S, Cl, K, Al, and Si that may give rise to or prevent deposits on tubes or on catalyst surfaces, or that may have an influence on the formation of dioxins. With better knowledge of these effects the positive ones can be utilised and the negative ones can be avoided.

Water and phase change material based photovoltaic thermal management systems: A review

Abstract: Photovoltaic panels are semiconductor materials having electrical efficiency in between 4% and 46% depending upon its material. About 50% of total solar radiation absorb by photovoltaic panel convert into heat causing high operating temperature of photovoltaic panel (PV) results to drop in its electrical performance and permanent structural damages called thermal degradation if a thermal stress remains in PV panel for long. So cooling of photovoltaic panel is very essential for better performance and long life of photovoltaic module. Many researchers have investigated performance of photovoltaic module by using different cooling arrangements having different thermal absorber design, different coolants and different phase change materials (PCMs). Detailed review of various methods related to water based photovoltaic/thermal system (PV/T) and photovoltaic panel with phase change material (PV-PCM) system has been discussed and reported in this paper. This review paper can help to find new cooling arrangements, different thermal absorber design and different phase change materials for improving performance of photovoltaic/thermal system. It has been observed from the literature that photovoltaic panel with phase change material (PV-PCM) is proficient solution for cooling of photovoltaic panel. But problems associated with phase change material are its low thermal conductivity and nocturnal solidification which affect its readiness and thermal drop performance for same day and next day therefore, performance of photovoltaic panel with phase change material (PV-PCM) system can be enhanced by inserting heat transfer elements within PCM and extracting heat from PCM to regulate temperature of phase change material to maintain its heating storage capacity. Extracted heat from PCM can be use for space heating or water heating applications.