14 resultados para Heat exchanger network (HEN)

em Deakin Research Online - Australia


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Internal combustion engines release about 1/3 of the energy bound in the fuel as exhaust waste gas energy and another 1/3 energy is wasted through heat transfer into the ambient. On the other hand losses through friction are the third largest root cause for energy loss in internal combustion engines. During city driving frictional losses can be of the same size as the effective work, and during cold start these losses are even bigger. Therefore it is obvious to utilise wasted exhaust energy to warm up the engine oil directly. Frictional losses of any engine can be reduced during part load. Sensitivity analyses have been conducted for different concepts that utilise exhaust energy to reduce engine viscosity and friction. For a new system with an exhaust gas/oil heat exchanger the following benefits have been demonstrated:

• Fuel consumption reductions of over 7% measured as an average over 5 NEDC tests
compared to the standard system configuration.
• Significant reductions in exhaust emissions, mainly CO and NOx have been achieved
• Significantly higher oil temperatures during cold start indicate large potential to
reduce engine wear through reduced water condensation in the crankcase
• Fuel consumption reductions of further 3.3% to 4.6% compared to the 7% measured
over the NEDC test can be expected under real world customer usage conditions at
lower ambient temperatures.

Oil temperature measurements and analysis resulted in the idea of a novel system with further potential to reduce fuel consumption. This Oil Viscosity Energy Recovery System (OVER 7™) consists of 3 key features that add significant synergies if combined in a certain way: an oil warm up circuit/bypass, including oil pressure control and Exhaust Gas/Oil Heat Exchanger. The system separates the thermal inertias of the oil in the engine galleries and the oil pan, reduces hydraulic pumping losses, increases the heat transfer from the cylinder head to the oil, and utilises the exhaust heat to reduce oil friction.

The project demonstrated that sensitivity analysis is an important tool for the evaluation of different concepts. Especially for new concepts that include transient heat transfer such a qualitative approach in combination with accurate experiments and measurements can be faster and more efficient in leading to the desired improvements compared to time consuming detailed simulations.

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A wide variety of evolutionary optimization algorithms have been used by researcher for optimal design of shell and tube heat exchangers (STHX). The purpose of optimization is to minimize capital and operational costs subject to efficiency constraints. This paper comprehensively examines performance of genetic algorithm (GA) and cuckoo search (CS) for solving STHX design optimization. While GA has been widely adopted in the last decade for STHX optimal design, there is no report on application of CS method for this purpose. Simulation results in this paper demonstrate that CS greatly outperforms GA in terms of finding admissible and optimal configurations for STHX. It is also found that CS method not only has a lower computational requirement, but also generates the most consistent results.

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This paper comprehensively investigates performance of evolutionary algorithms for design optimization of shell and tube heat exchangers (STHX). Genetic algorithm (GA), firefly algorithm (FA), and cuckoo search (CS) method are implemented for finding the optimal values for seven key design variables of the STHX model. ε-NTU method and Bell-Delaware procedure are used for thermal modeling of STHX and calculation of shell side heat transfer coefficient and pressure drop. The purpose of STHX optimization is to maximize its thermal efficiency. Obtained results for several simulation optimizations indicate that GA is unable to find permissible and optimal solutions in the majority of cases. In contrast, design variables found by FA and CS always lead to maximum STHX efficiency. Also computational requirements of CS method are significantly less than FA method. As per optimization results, maximum efficiency (83.8%) can be achieved using several design configurations. However, these designs are bearing different dollar costs. Also it is found that the behavior of the majority of decision variables remains consistent in different runs of the FA and CS optimization processes.

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Die Erfindung betrifft einen Verbrennungsmotor (1) mit zumindest einer Abgasleitung (2), in der ein Wärmetauscher (4) angeordnet ist, und mit einer dem Wärmetauscher (4) umführenden Bypaßleitung (13). Der Verbrennungsmotor (1) weist einen Motorölkreislauf (6) auf. Dem Wärmetauscher (4) ist zumindest stromaufwärts eines Abgasstromes ein Mehrwegeventil (12) vorgeschaltet. Der Wärmetauscher (4) ist in dem Motorölkreislauf (6) integriert, so daß das Motoröl in einer Warmlaufphase des Verbrennungsmotors (1) mittels der Abgaswärme aufgeheizt wird.
Combustion engine comprises an exhaust gas line (2) containing a heat exchanger (4) connected to a multiple way valve (12) upstream of an exhaust gas stream. The heat exchanger is integrated into an engine oil cycle (13) so that the oil is heated in a hot running phase of the engine using the exhaust gas heat. Preferred Features: The multiple way valve is formed as a three-way valve connected with two connections to the exhaust gas line and with one connection to a bypass. A siphon (14) is connected to the heat exchanger.

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A pneumatic vehicle is provided with a first sub-assembly with a chassis, part of the vehicle body, a pair of B-pillars, a pair of rear rails, wheels, an elongate aluminum compressed load bearing air tank oriented longitudinally in the chassis, side panels connected to the tank and the wheels, a heat exchanger to heat the compressed air, and an air motor driven by the heated, compressed air and connected to a wheel. A ventilation system has a restrictive solenoid valve for directing air to the heat exchanger. The air tank is provided with a carbon filament reinforced plastic layer, and a fiberglass and aramid-fiber layer. A second sub-assembly includes part of the vehicle body bonded to the first-sub-assembly using a structural adhesive, a pair of A-pillars, and a pair of roof rails. Seating includes inflatable components for adjustment.

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A pneumatic vehicle is provided with a first sub-assembly with a chassis, part of the vehicle body, a pair of B-pillars, a pair of rear rails, wheels, an elongate aluminum compressed load bearing air tank oriented longitudinally in the chassis, side panels connected to the tank and the wheels, a heat exchanger to heat the compressed air, and an air motor driven by the heated, compressed air and connected to a wheel. A ventilation system has a restrictive solenoid valve for directing air to the heat exchanger. The air tank is provided with a carbon filament reinforced plastic layer, and a fiberglass and aramid-fiber layer. A second sub-assembly includes part of the vehicle body bonded to the first-sub-assembly using a structural adhesive, a pair of A-pillars, and a pair of roof rails. Seating includes inflatable components for adjustment.

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A pneumatic vehicle is provided with a chassis, wheels, a compressed air tank, a heat exchanger to heat the compressed air, and an air motor driven by the heated air and connected to at least one wheel. A pneumatic vehicle is provided with a chassis, wheels, a compressed air tank, and an air motor driven by the compressed air and connected to a wheel. The vehicle also has a ventilation system for the passenger compartment, a heat exchanger, and a restrictive solenoid valve for directing ventilation system air to the heat exchanger. A pneumatic vehicle is provided with a chassis, wheels, an aluminum compressed air tank, a carbon filament reinforced plastic layer over the tank, a fiberglass and aramid-fiber layer over the carbon filament reinforced plastic layer, and an air motor driven by the compressed air and connected to at least one wheel.

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A pneumatic vehicle is provided with a first sub- assembly with a chassis, part of the vehicle body, a pair of B-pillars, a pair of rear rails, wheels, an elongate aluminum compressed load bearing air tank oriented longitudinally in the chassis, side panels connected to the tank and the wheels, a heat exchanger to heat the compressed air, and an air motor driven by the heated, compressed air and connected to a wheel. A ventilation system has a restrictive solenoid valve for directing air to the heat exchanger. The air tank is provided with a carbon filament reinforced plastic layer, and a fiberglass and aramid-fiber layer. A second sub-assembly includes part of the vehicle body bonded to the first-sub-assembly using a structural adhesive, a pair of A-pillars, and a pair of roof rails. Seating includes inflatable components for adjustment.

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A pneumatic vehicle is provided with a first sub-assembly with a chassis, part of the vehicle body, a pair of B-pillars, a pair of rear rails, wheels, an elongate aluminum compressed load bearing air tank oriented longitudinally in the chassis, side panels connected to the tank and the wheels, a heat exchanger to heat the compressed air, and an air motor driven by the heated, compressed air and connected to a wheel. A ventilation system has a restrictive solenoid valve for directing air to the heat exchanger. The air tank is provided with a carbon filament reinforced plastic layer, and a fiberglass and aramid-fiber layer. A second sub-assembly includes part of the vehicle body bonded to the first-sub-assembly using a structural adhesive, a pair of A-pillars, and a pair of roof rails. Seating includes inflatable components for adjustment.

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A pneumatic vehicle is provided with a chassis, wheels, a compressed air tank, a heat exchanger to heat the compressed air, and an air motor driven by the heated air and connected to at least one wheel. A pneumatic vehicle is provided with a chassis, wheels, a compressed air tank, and an air motor driven by the compressed air and connected to a wheel. The vehicle also has a ventilation system for the passenger compartment, a heat exchanger, and a restrictive solenoid valve for directing ventilation system air to the heat exchanger. A pneumatic vehicle is provided with a chassis, wheels, an aluminum compressed air tank, a carbon filament reinforced plastic layer over the tank, a fiberglass and aramid-fiber layer over the carbon filament reinforced plastic layer, and an air motor driven by the compressed air and connected to at least one wheel.

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A pneumatic vehicle is provided with a first sub-assembly with a chassis, part of the vehicle body, a pair of B-pillars, a pair of rear rails, wheels, an elongate aluminum compressed load bearing air tank oriented longitudinally in the chassis, side panels connected to the tank and the wheels, a heat exchanger to heat the compressed air, and an air motor driven by the heated, compressed air and connected to a wheel. A ventilation system has a restrictive solenoid valve for directing air to the heat exchanger. The air tank is provided with a carbon filament reinforced plastic layer, and a fiberglass and aramid-fiber layer. A second sub-assembly includes part of the vehicle body bonded to the first-sub-assembly using a structural adhesive, a pair of A-pillars, and a pair of roof rails. Seating includes inflatable components for adjustment.

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Artificial neural networks have a good potential to be employed for fault diagnosis and condition monitoring problems in complex processes. In this paper, the applicability of the fuzzy ARTMAP (FAM) neural network as an intelligent learning system for fault detection and diagnosis in a power generation plant is described. The process under scrutiny is the circulating water (CW) system, with specific attention to the conditions of heat transfer and tube blockage in the CW system. A series of experiments has been conducted systematically to investigate the effectiveness of FAM in fault detection and diagnosis tasks. In addition, a set of domain rules has been extracted from the trained FAM network so that its predictions can be explained and justified. The outcomes demonstrate the benefits of employing FAM as an intelligent fault detection and diagnosis tool with an explanatory capability for monitoring and diagnosing complex processes in power generation plants.

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This paper describes the application of an adaptive neural network, called Fuzzy ARTMAP (FAM), to handle fault prediction and condition monitoring problems in a power generation station. The FAM network, which is supplemented with a pruning algorithm, is used as a classifier to predict different machine conditions, in an off-line learning mode. The process under scrutiny in the power plant is the Circulating Water (CW) system, with prime attention to monitoring the heat transfer efficiency of the condensers. Several phases of experiments were conducted to investigate the `optimum' setting of a set of parameters of the FAM classifier for monitoring heat transfer conditions in the power plant.

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Microstructure evolution after solutionizing and ageing treatment of cast AZ80 Mg alloy were investigated using optical and scanning electron microscopy. Effect of these treatments on grain size, β-Mg17Al12 intermetallic phase, mechanical behavior, and flow asymmetry were investigated. The initial continuous network of β-phase found to be reduced after solutionizing. The dissolution of β-phase and simultaneous grain growth are found to be interrelated. Mechanical properties including yield strength, maximum strength (ultimate compressive strength), and maximum strain attainable in compressive found almost twice than the corresponding values obtained in tension. The asymmetry in compressive and tensile properties is found to decrease with grain size at certain solutionizing duration. Particular heat treatment found to offer best combination of tensile compressive flow properties in AZ80 Mg alloy. Aging under certain conditions found to minimize the strength asymmetry. © ASM International.