A method of cooling an electronics cabinet includes inducing a flow of cooling air to enter into the electronics cabinet, passing the flow of cooling air over electronic modules arranged within the electronics cabinet to convectively transfer heat to the flow of cooling air from the electronic modules, and directing the flow of cooling air through a door heat exchanger at an end of the electronics cabinet to exhaust the flow of cooling air from the cabinet. A first coolant flow is directed through the door heat exchanger, and heat is transferred from the flow of cooling air to the first coolant flow as they pass through the door heat exchanger. A second coolant flow is circulated through a coolant loop that is arranged within the electronics cabinet, and passes though cold plates that are joined to at least some of the electronic modules to transfer heat from those modules to the second coolant flow. Heat from the second coolant flow is transferred to the first coolant flow in a coolant-to-coolant heat exchanger arranged within the electronics cabinet. Heat is subsequently rejected from the first coolant flow at a location remote from the electronics cabinet.