The objective of this paper is to study the pool boiling heat transfer characteristics of twisted tubes in a flooded evaporator.The twisted tubes are processed from common circular evaporating tubes with an outer diameter of 15.88 mm.The outer and inner diameters

wall thickness and length of the twisted tube are 19.50

11.28

1.09

and 3310 mm

respectively.With the same number of tubes

the twisted tube flooded evaporator(TFE) requires smaller heat exchange area than the common flooded evaporator(FE).The pool boiling heat transfer coefficients outside tubes

tube side Reynolds number Rei

wall superheat Tsup

saturation temperature of refrigerant Tsat and heat flux qb are considered as the key parameters.The results show that pool boiling heat transfer coefficient increases with Rei

Tsat and qb and decreases as Tsup increases.The case study shows that the overall heat transfer coefficient of TFE is about 1.15 times that of FE with the same heat capacity.It is proved that the application of TFE in the water-cooled screw chiller is feasible.