A cooling system for cooling air from a data center, the cooling system comprising: a cooling device in fluid communication with the data center; an indirect free cooling module comprising: an adiabatic device in fluid communication with a source of external air and configured to cool the source of external air to produce cooled external air; and at least one heat exchanger configured to be in fluid communication with the adiabatic device and a flow of air from the data center and to cool the flow of air from the data center with the cooled external air produced by the adiabatic device to produce treated air; a damper system in fluid communication with the flow of air from the data center, the cooling device, and the at least one heat exchanger of the indirect free cooling module such that an inlet of a first damper of the damper system is in fluid communication with the flow of air from the data center and an outlet of the first damper is in fluid communication with an inlet to the cooling device, and an inlet of a second damper of the damper system is in fluid communication with the treated air from the heat exchanger and an outlet of the second damper is in fluid communication with the inlet to the cooling device; and a control system in communication with the damper system and configured to selectively direct the flow of air from the data center to an inlet of the at least one heat exchanger and through the second damper to an inlet of the cooling device, or through the first damper to the inlet of the cooling device, or to both the inlet of the at least one heat exchanger and through the second damper to the inlet of the cooling device, and through the first damper to the inlet of the cooling device. a cooling device in fluid communication with the data center; an indirect free cooling module comprising: an adiabatic device in fluid communication with a source of external air and configured to cool the source of external air to produce cooled external air; and at least one heat exchanger configured to be in fluid communication with the adiabatic device and a flow of air from the data center and to cool the flow of air from the data center with the cooled external air produced by the adiabatic device to produce treated air; an adiabatic device in fluid communication with a source of external air and configured to cool the source of external air to produce cooled external air; and at least one heat exchanger configured to be in fluid communication with the adiabatic device and a flow of air from the data center and to cool the flow of air from the data center with the cooled external air produced by the adiabatic device to produce treated air; a damper system in fluid communication with the flow of air from the data center, the cooling device, and the at least one heat exchanger of the indirect free cooling module such that an inlet of a first damper of the damper system is in fluid communication with the flow of air from the data center and an outlet of the first damper is in fluid communication with an inlet to the cooling device, and an inlet of a second damper of the damper system is in fluid communication with the treated air from the heat exchanger and an outlet of the second damper is in fluid communication with the inlet to the cooling device; and a control system in communication with the damper system and configured to selectively direct the flow of air from the data center to an inlet of the at least one heat exchanger and through the second damper to an inlet of the cooling device, or through the first damper to the inlet of the cooling device, or to both the inlet of the at least one heat exchanger and through the second damper to the inlet of the cooling device, and through the first damper to the inlet of the cooling device. <EOS>