A modular data center, for housing and cooling electronic equipment, includes multiple housings, a first portion of the housings configured to hold heat-producing electronic equipment and a second portion of the housings configured to hold at least one cooling unit, each of the housings of the first portion having a front and a back and configured to hold the heat-producing electronic equipment such that gas is drawn into the equipment from fronts of the equipment, heated by the equipment to become heated gas, and expelled by the electronic equipment is expelled through the backs of the housings, where the housings are disposed and coupled to form a laterally-enclosed arrangement laterally enclosing a hot region and defining a top opening allowing gas to vertically exit the hot region, and where backs of the housings of the first portion are disposed adjacent to the hot region such that the heat-producing equipment, when mounted to the housings, will expel the heated gas into the hot region.