Comparative analysis of inlet air cooling techniques integrated to cooled gas turbine plant

The current article is focused on assessing the comparison of two different means of inlet air cooling (evaporative cooing and vapor compression cooling) integrated to a cooled gas turbine power plant. Air film cooling has been adopted as the cooling technique for gas turbine buckets. A parametric study of the effect of pressure ratio (rp,c), compressor inlet temperature (CIT), turbine inlet temperature (TIT), inlet temperature ratio (rIT), ambient relative humidity and ambient temperature on performance parameters of plant has been carried out. It has been observed that the integration of the inlet air cooling system to the gas turbine cycle improves the overall performance, the improvement being higher at higher ambient temperature and ambient relative humidity. At a TIT = 1700 K, rp,c = 23, RHa = 0.2 and Ta = 313 K, vapor compression inlet air cooling has been observed to improve the plant specific work by 18.4% and efficiency by 4.18%, compared to 10.48% and 4.6% respectively for evaporative cooling. In geographical regions having low ambient relative humidity and low ambient temperature however, evaporative inlet air cooling should be preferred over vapor compression cooling in terms of higher plant efficiency.. The adoption of higher turbine inlet temperature has a more pronounced effect on vapor compression cooled gas turbine in terms of enhancement in plant performance parameters as compared to evaporative cooling. The work ratio increases with increase in value of rIT upto5.6 after which it decreases.