in this paper, first a sensitivity analysis of parameters affecting the performance of the steam generator is performed. this process includes the pinch temperature difference and the gas velocity (width of the hrsg) as the operating parameter and geometrical parameters (fin’s thickness, fin’s height, number of fins in each inch, tube transverse pitch) for each pressure parts is carried out, an...

In this paper exergy analysis is used to assess the performance of the three most common air conditioning plant schemes: all-air, dual-duct and fan-coil systems. The results are presented in terms of flow diagrams to provide a clear picture of the exergy flow across the systems. The most relevant outcomes are that the air cooling and dehumidification is the process most responsible for the exer...

in this paper, a new combined power and refrigeration cycle is proposed, which combines the rankin power cycle and the ejector refrigeration cycle. this combined cycle produces both power output and refrigeration output simultaneously. this cycle is driven by the flue gas of gas turbines, industrial waste heats, solar energy and geothermal energy. an exergy analysis is performed to guide the th...

The objectives of this study are to (a) evaluate the exergy and energy demand for constructing a hydrofractured shale gas well and determine its typical exergy and energy returns on investment (ExROI and EROI), and (b) compute the gas flow and intrinsic exergy analysis in the shale gas matrix and created fractures. An exergy system analysis of construction of a typical U.S. shale gas well, whic...

In this study, exergy analysis of a novel desalination system is presented and discussed. The water desalination is carried out using combined humidification-dehumidification and reverse osmosis technologies. Six system performance parameters are examined: overall exergetic efficiency, equivalent electricity consumption, specific exergy destruction, specific exergy lost, and total true specific...

Comparative energy and exergy investigations are reported for a transcritical N2O refrigeration cycle with a throttling valve or with an expander when the gas cooler exit temperature varies from 30 to 55 ◦C and the evaporating temperature varies from −40 to 10 ◦C. The system performance is also compared with that of similar cycles using CO2. Results show that the N2O expander cycle exhibits a l...

Of evaporative cooling or energy recovery potential in HVAC, the conventional thermodynamic analysis is based on the enthalpy of moist air. In fact, the available energy of moist air is its exergy and the available energy saving potential ought to be the exergy. Isoexergic lines on psychometric charts associated with different ambient states persuade us that exergy and enthalpy are completely i...

The second law of thermodynamics and, specifically, exergy analysis have been traditionally used for the assessment and optimization of energy systems. Nevertheless, as shown in this paper, exergy could also constitute a powerful tool for the evaluation of mineral commodities. That said, new or re-defined exergy-based concepts need to be developed. This paper presents Thanatia as a baseline for...

A single vacuum tube based solar cooker has high energy and exergy efficiency, and is capable of achieving cooking temperatures as high as 250 C. The reason for high energy and exergy efficiencies of this solar cooker is the high achievable concentration ratios of 15e20, which are not possible with multiple vacuum tube based solar cookers. In this paper, a comparative study has been carried out...

Contaminants cause a decrease in the quality of materials with each recycling step. These quality losses should be minimized to increase the sustainability of resources use. Quality losses cannot be measured using weight-based recovery definitions alone, as the quality degradation cannot be translated by mass measures. Therefore, a better measure of the efficiency of resource use is investigate...