Experimental investigation on the off-design performance of a small-sized humid air turbine cycle

► We built a flexible small-size test rig of HAT cycle gas turbine and the real test data were reported and analyzed. ► The HAT cycle with higher humidity ratio exhibits higher thermal efficiency and lower NOx emission. ► Good agreement between theoretical and experimental results. ► Increasing the humidity ratio can move the compressor running line away from the surge line. ► Introducing a recuperator to the existing HAT cycle will greatly increase cycle efficiency.