Heat exchange apparatus and ventilation system using the same

A heat exchange apparatus, comprising:

• a heat exchanger comprising a first side and a second side, wherein the heat exchanger is configured to allow an air or gas to flow therethrough between the first side and the second side, wherein the heat exchanger is further configured to exchange heat with the air or gas flowing therethrough between the first side and the second side;
• a first rotary valve configured to let the air or gas flow to or from the first side of the heat exchanger and configured to rotate about a first axis, wherein the first rotary valve is further configured to change flow directions of the air or gas as rotating about the first axis;
• and
• a second rotary valve configured to let the air or gas flow to or from the second side of the heat exchanger and configured to rotate about a second axis, wherein the second rotary valve is further configured to change flow directions of the air or gas as rotating about the second axis,
• wherein the second rotary valve is configured to rotate in synchronization with the first rotary valve so as to form a plurality of predetermined flow modes,
• wherein the first rotary valve comprises a first rotary valve side, a second rotary valve side and a circumference interconnecting the first and second rotary valve sides thereof, the first rotary valve side comprising a first side opening, the second rotary valve side comprising a second side opening, the circumference comprising a first circumferential opening and a second circumferential opening, wherein the first circumferential opening is in fluid communication with the first side opening, wherein the second circumferential opening is in fluid communication with the second side opening.