System for cooling one or more computer servers and for producing heat from the heat recovered from the server(s), comprising: - a sealed container filled with a dielectric oil; - at least one electronics board supporting one or more electronic components, the electronics board being arranged vertically inside the container, between a lower portion and an upper portion of the container and immersed in the dielectric oil; - at least one plate, called "cold plate",, each cold plate being thermally coupled to one or more of the electronic components of one and the same board that generate the greatest amount of heat; - a water/oil exchanger, arranged outside the container; - an oil pump; - a closed fluid circuit, the fluid containing the dielectric oil placed in circulation by the oil pump, the closed circuit comprising, in fluidic series: • one of the circuits, called "oil circuit", of the exchanger, • at least one conduit connecting the oil circuit of the exchanger to the lower portion or the upper portion of the interior of the container, • the interior of the container, • at least one conduit (50, 51) connecting the upper portion or the lower portion of the interior of the container to the inlet of the cold plate, • at least one conduit connecting the outlet of the cold plate to the oil circuit of the exchanger, the closed fluid circuit thus being configured such as to provide cooling of the cold plate at the outlet and in series with the cooling of the one or more electronic components. - a sealed container filled with a dielectric oil; - at least one electronics board supporting one or more electronic components, the electronics board being arranged vertically inside the container, between a lower portion and an upper portion of the container and immersed in the dielectric oil; - at least one plate, called "cold plate",, each cold plate being thermally coupled to one or more of the electronic components of one and the same board that generate the greatest amount of heat; - a water/oil exchanger, arranged outside the container; - an oil pump; - a closed fluid circuit, the fluid containing the dielectric oil placed in circulation by the oil pump, the closed circuit comprising, in fluidic series: • one of the circuits, called "oil circuit", of the exchanger, • at least one conduit connecting the oil circuit of the exchanger to the lower portion or the upper portion of the interior of the container, • the interior of the container, • at least one conduit (50, 51) connecting the upper portion or the lower portion of the interior of the container to the inlet of the cold plate, • at least one conduit connecting the outlet of the cold plate to the oil circuit of the exchanger, the closed fluid circuit thus being configured such as to provide cooling of the cold plate at the outlet and in series with the cooling of the one or more electronic components. • one of the circuits, called "oil circuit", of the exchanger, • at least one conduit connecting the oil circuit of the exchanger to the lower portion or the upper portion of the interior of the container, • the interior of the container, • at least one conduit (50, 51) connecting the upper portion or the lower portion of the interior of the container to the inlet of the cold plate, • at least one conduit connecting the outlet of the cold plate to the oil circuit of the exchanger,