<p>A cooling system of the invention has heat exchange means which is housed in one enclosure (1) and is constituted of a plurality of heat exchange modes, and the heat exchange means includes a refrigerant forced circulation mode, a refrigerant natural circulation mode, and a ventilation mode. Temperature detection means performs switching to an optimal mode, to hereby cool the inside of the enclosure (31) of a housing (30) accommodating equipment (32) including a heat-generating component (33).
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