1) Anti freezingWater is not easy to get frozen because water is in a turbulence state as flow in the spiral groove inner tube at low speed. And the special spiral groove sturcture of inner tube makes the inner tube has a ability of flexibility, so it will not risk of frost crack.
2) Self cleaning, no blockFluid flow helically to scour the surface, so the coaxial heat exchanger has a bility of self cleaning. And the coaxial heat excahnger's performance is stable and has less attenuation. The sectional area of water passway is bigger so it allowed silt, fiber of big diameter to get through without get blocked. The passeay of water is clean because spiral grooves inner tube makes water flow in turbulence state that will clean the surface.
Inner tube material
Inner tube material can be: red copper, cupronickel(BFe-10-1-1), Titanium, Stainless steel. And inner tube can be choosed by smooth tube or enhanced surface tube. And there are also double-wall copper inner tube.