Experimental Investigations for Fluid Flow Characteristics of Refrigerant R134a in a Microtubes Evaporator

The experiment on the fluid flow characteristics of R134a in an evaporator with horizontal microtube was performed. In this study, the air volume flow rate and the ambient temperature has changed from 19 to 47.5 l/s and 26 to 32 °C, respectively. Besides, a comparison between the micro evaporator and the macro evaporator (FNA) was also conducted. The pressure drop of the macro evaporator is lower than that obtained from the micro evaporator. Almost cases, the latent heat is dominant to compare with the sensible heat. These results indicated that the microevaporator is appropriate for some applications in dehumidity fields. In experimental conditions, the pressure drop of the microevaporator increases with increasing the air volume flow rate; especially, the influence is so strongly with the high ambient temperature from 30 to 320C. In addition, the pressure drop is highly depended on the saturation pressure: the higher saturation pressure, the larger the pressure drop.