Liquid cooling device and projection device

A projection device, comprising:

• an illumination system, a light valve, a projection lens, and a cooling system, wherein the illumination system comprises a light source, the light source is adapted to provide an illumination beam, the light valve is disposed on a transmission path of the illumination beam to convert the illumination beam into an image beam, the projection lens is disposed on a transmission path of the image beam, and the cooling system comprises a liquid cooling device, at least one heat absorbing element, and a liquid conveying pipeline, wherein
• the liquid cooling device comprises a first liquid cooling row, a second liquid cooling row, and a fan, wherein
• the first liquid cooling row has a first inflow end and a first outflow end for liquid to flow from the first inflow end to the first outflow end in a first direction;
• the second liquid cooling row is disposed opposite to the first liquid cooling row, the second liquid cooling row has a second inflow end and a second outflow end, and the second inflow end is connected to the first outflow end for the liquid flowing out of the first outflow end to flow from the second inflow end to the second outflow end in a second direction, wherein the first direction is opposite to the second direction;
• and
• the fan is adapted to generate airflow, and the airflow sequentially flows through the second liquid cooling row and the first liquid cooling row to cool the liquid;
• the at least one heat absorbing element is connected to at least one of the light source and the light valve, and the heat absorbing element has a liquid inflow end and a liquid outflow end;
• and
• the liquid conveying pipeline is connected in series with the heat absorbing element and the liquid cooling device, wherein the liquid flowing out from the second outflow end flows into the heat absorbing element through the liquid conveying pipeline and the liquid inflow end and flows into the first inflow end through the liquid outflow end and the liquid conveying pipeline.