The objective of this paper is to study the heat transfer performance of twisted-tube dry-expansion evaporator (TDE) and conventional baffle dry-expansion evaporator (BDE). The effect of evaporating temperature (Te)

condensing temperature (Tc)

Reynolds number (Reo) outside tube and heat flux (qi) on heat transfer performance was investigated. The results showed that with the increase of Te

Reo and qi

the heat transfer performances of TDE and BDE were increased

while with the increase of Tc

both of the heat transfer performances were decreased. The air-cooled heat pump (ACHP) applied with TDE and BDE was tested

respectively. The results showed that at the same cooling state the overall heat transfer coefficient (K) of TDE was 36.3% higher than that of BDE

and the ACHP's cooling coefficient of performance (COP) was increased by 6.0%. At the same heating state

the K of TDE was 41.7% higher than that of BDE and the ACHP's heating COP was increased by 15.8%. It was proved that TDE applied in ACHP was feasible

and its performance was better than BDE.