... series of products of heat exchanger core:heat exchanger air to air coreTotal heat exchanger(sensible and latent heat) core: ... material,Countercurrent heat exchange mode,efficiency high to 75%,ABS frame structure,low flow resistance,no distortion,tightness and ... ventilate rate is low, the inside fresh air and the outside return air are isolated completely.Patent number,ZL200420116088.5, ...