Evaporator performances for direct-expansion air conditioning units dedicated to underground railway station

Establishes an experimental test bench of direct-expansion air conditioner to test the thermal performance of elliptical tube and circular tube evaporators. Simulates the thermal performance of evaporators by Fluent software. Experimental and simulation results show that the elliptical tube evaporator has excellent thermal performance. By comparing three indexes of cooling capacity per unit area under unit power, ratio of heat transfer coefficient to power consumption, ratio of Nu to power consumption, the indexes values of elliptical tube is 58.3%,54.6% and 65.6% higher than those of circular tube respectively.