Evaporative regenerative cycle

Figure 2-24. Performance map showing the effect of pressure ratio and steam flow rate on an evaporative regenerative cycle.

The CHAT cycle may be seen as a low loss evaporative development of the dry intercooled, reheated regenerative cycle [CICBTBTX]. It offers some thermodynamic advantage—increase in turbine work (and heat supplied ) with little or no change in the compressor work, leading to an increased thermal efficiency and specific work output. 

Table 2. Variation in cooling COP of a zeolite - water regenerative cycle with evaporating, condensing, adsorption rejection and maximum desorption temperatures 0°C, 40°C, 50°C and 350°C respectively.

In order to clarify these ideas, we need to compare the irreversible entropy productions (or the exergy destruction) in cycles that utilize regenerative heating of compressed air, thermal recuperation in the form of evaporation and superheating of the methanol fuel, and chemical recuperation through either reforming or cracking reaction with methanol. The next section presents such a comparison in a simplified form to illustrate the utility of thermodynamic analyses. 

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