Optimal performance of an irreversible, heat engine-driven, combined vapor compression and absorption refrigerator

By employing finite-time thermodynamic approach, the optimum performance of an irreversible heat engine-driven combined vapor compression and absorption refrigerator system is investigated. To get closer to real machines, the effects of thermal resistances and internal irreversibilities on the performance of the combined cycle is considered. The analysis show that the combined cycle has a significant increase in system performance over the heat engine-driven vapor-compression refrigerators.

Optimum performance of irreversible cascaded and double effect absorption refrigerators

The effects of thermal resistances and internal irreversibilities on the performances of cascaded and double effect absorption refrigeration cycles were investigated. Improved equations for the coefficient of performance (COP) of the systems under consideration were obtained. It was found that, under the same operation conditions, the cascaded cycle gives an increase of about 60% in the COP and 40% in the cooling load compared to that of a double effect cycle.

Performance analysis of an irreversible cascaded heat-transformer

By employing an irreversible thermodynamic approach the optimum performance of an cascaded absorption heat-transformer system is investigated. To get closer to real machines, the effects of thermal resistances and internal irreversibilities on the performance of the cascaded cycle is considered. An improved equation for the coefficient of performance (COP) of the system under consideration was obtained. The analyses show that the cascaded cycle has a significant increase in the systems gross temperature lift (GTL) over the single stage heat-transformer.Cascaded Heat transformer Irreversible Gross temperature lift

Optimal design of the regenerative gas turbine engine with isothermal heat addition

A regenerative gas turbine engine, with isothermal heat addition, working under the frame of a Brayton cycle has been analyzed. With the purpose of having a more efficient small-sized gas turbine engine, the optimization has been carried out numerically using the maximum power (MP) and maximum power density (MPD) method. The effects of internal irreversibilities have been considered in terms of the isentropic efficiencies of the turbine and compressor and of the regenerator efficiency. The results summarized by figures show that the regenerative gas turbine engine, with isothermal heat addition, designed according to the maximum power density condition gives the best performance and exhibits highest cycle efficiencies.