Ecological Coefficient Of Performance Criterion Research Articles

Thermo-ecological performance analyses and optimizations of irreversible gas cycle engines

This paper reports ecological performance analyses and optimization of irreversible gas cycle engines such as Joule–Brayton cycle (JB), Atkinson cycle (AC), Otto cycle (OC), Diesel cycle (DC), Miller cycle (MC), Dual-Atkinson cycle (DAC), Dual-Diesel cycle (DDC), Dual-Miller cycle (DMC) engines based on the ecological coefficient of performance (ECOP) criterion which covers internal irreversibility, heat leak and finite-rate of heat transfer. Comprehensive computational analyses have been conducted to investigate the global and optimal performances of the gas cycle engines. The results obtained based on the ECOP criterion are compared with a different ecological function which is named as the ecologic objective-function and with the maximum power output conditions. The results have been acquired introducing the compression ratio, cut-off ratio, pressure ratio, air recharging ratio, source temperature ratio and internal irreversibility parameter. The changes of cycle performances with respect to these parameters are examined and demonstrated with figures.

Performance optimization of an air-standard irreversible dual-atkinson cycle engine based on the ecological coefficient of performance criterion.

This paper presents an ecological performance analysis and optimization for an air-standard irreversible Dual-Atkinson cycle (DAC) based on the ecological coefficient of performance (ECOP) criterion which includes internal irreversibilities, heat leak, and finite-rate of heat transfer. A comprehensive numerical analysis has been realized so as to investigate the global and optimal performances of the cycle. The results obtained based on the ECOP criterion are compared with a different ecological function which is named as the ecologic objective-function and with the maximum power output conditions. The results have been attained introducing the compression ratio, cut-off ratio, pressure ratio, Atkinson cycle ratio, source temperature ratio, and internal irreversibility parameter. The change of cycle performance with respect to these parameters is investigated and graphically presented.

Irreversible three-heat-source refrigerator with heat transfer law of QαΔ(T −1) and its performance optimization based on ECOP criterion

The new thermo-ecological optimization of an absorption system for cooling applications operating between three temperature levels with the linear phenomenological heat transfer law of \(\dot{Q}\alpha\Delta( T^{ - 1} )\) has been performed by taking account the losses of heat resistance, internal irreversibility and leakage. The considered objective function is the ecological coefficient of performance (ECOP) and is defined as the cooling load per unit loss rate of availability. The comparative analysis with the ecological optimization criterion (E) defined in the literature and also with the cooling load optimization criterion (R) has been carried out to prove the utility of the new thermo-ecological optimization criterion (ECOP) for three-heat-source refrigerators with linear phenomenological heat transfer law. The results show that the three-heat-source refrigeration cycle working at maximum ECOP conditions has a significant advantage in terms of entropy production rate and coefficient of performance over the maximum E and maximum R conditions. The obtained results may provide a general theoretical tool for the thermo-ecological design of absorption refrigerator.

Performance analysis and optimization of irreversible air refrigeration cycles based on ecological coefficient of performance criterion

In this paper, a performance optimization based on ecological coefficient of performance (ECOP) criterion has been carried out for an irreversible air refrigeration cycles. The considered model includes irreversibilities due to finite-rate heat transfer, heat leakage and internal dissipations. The ECOP objective function is defined as the ratio of cooling load to the loss rate of availability (or entropy generation rate). The maximum of the ecological performance criterion and the corresponding optimal conditions have been derived analytically. The effects of irreversibility parameters on the general and optimal performances discussed detailed. The obtained results may provide a general theoretical tool for the ecological design of air refrigerators.

06/02274 Performance analysis of an irreversible Brayton heat engine based on ecological coefficient of performance criterion: Ust, Y. et al. International Journal of Thermal Sciences, 2006, 45, (1), 94-101

06/02274 Performance analysis of an irreversible Brayton heat engine based on ecological coefficient of performance criterion: Ust, Y. et al. International Journal of Thermal Sciences, 2006, 45, (1), 94-101

06/00780 Performance analysis and optimization of an irreversible dual-cycle based on an ecological coefficient of performance criterion: Ust, Y. et al. Applied Energy, 2005, 82, (1), 23–39.

06/00780 Performance analysis and optimization of an irreversible dual-cycle based on an ecological coefficient of performance criterion: Ust, Y. et al. Applied Energy, 2005, 82, (1), 23–39.

Performance analysis of an irreversible Brayton heat engine based on ecological coefficient of performance criterion

A performance optimization based on a new ecological criterion called ecological coefficient of performance (ECOP) has been presented for irreversible Brayton heat engine. The considered model includes irreversibilities due to finite rate heat transfer, heat leakage and internal dissipations. The ECOP objective function is defined as the ratio of power output to the loss rate of availability. The optimal performance and design parameters at maximum ECOP conditions are obtained analytically. The effects of major parameters on the general and optimal ecological performances have been investigated. The obtained results based on ECOP criterion are compared with an alternative ecological objective function defined in the literature and the maximum power output conditions, in terms of entropy generation rate, thermal efficiency and power output.

Performance analysis and optimization of an irreversible dual-cycle based on an ecological coefficient of performance criterion

An ecological performance analysis for an irreversible dual cycle has been performed by employing the new thermo-ecological criterion as the objective function. The objective function is the ecological coefficient of performance (ECOP) and defined as the power output per unit loss rate of availability. A comprehensive numerical study is carried out to investigate the general and optimal performances of the irreversible dual-cycle having a finite-rate of heat transfer, heat leak and internal irreversibilities based on the ECOP objective function. Comparisons with an alternative ecological function defined in the literature and also with the maximum power output condition are provided to establish the utility of the new ecological performance coefficient. The results indicate that the dual cycle considered working at maximum ECOP conditions has a significant advantage in terms of entropy-generation rate and thermal efficiency.