High efficient heat transferring
Using high efficiency rifle tube, heat exchange area is 3.6 times than the smooth type.the inner coil of copper tube is finned,which has more heat transferring area almost 3.6 times than that of smooth copper tube.Outer fin and inner screw  of the copper tube can cause turbulance with both water and refrigerant which helps improve the heat transferring efficiency.

Safety
no weld joints on copper tube,ensure stablity when working long-time. We assemble copper tube to shell after set-up to avoid flaw during manufacturing. No blind area over water side,avoid partial freezing and scaling.

Compact structure 
small volume can contribute a lot to whole heat pump unit to reduce and save enough room .