A modular cooling apparatus for cooling one or more rack-mounted electronic component enclosures in a datacenter includes a base duct section and a duct assembly. The base duct section includes an inlet to receive a cooling airflow and an outlet to transfer to the cooling airflow to the duct assembly. The duct assembly is connected to the base duct section. The duct assembly includes one or more modular duct sections. Each of the one or more modular duct sections has a vent and is configured such that the vent aligns with an exterior opening in the respective one of the one or more electronic component enclosures.