The results of experimental investigations of heat transfer during the flow of R134a in a minichannel are presented here. The experimental investigations were conducted using a minichannel with a total length of 500 mm and 1.68 mm internal diameter. The heated length of the minichannel was 200 mm, the total mass flow rate of the refrigerant (w rho) = 200-450 kg/m(2) s. the inlet subcooling Delta T-s = 5-15 K, and the heat flux density q = 1.7-60 3 kW/m(2). The results of experimental investigations are presented as a boiling curve. The phenomenon known as the zero boiling crisis and the influence of the flashing phenomenon on the boiling curve show the importance of these elements on heat transfer in single- and two-phase systems. (C) 2009 Elsevier Ltd. All rights reserved.