A refrigeration system comprises a piurality of assembled modular units each having a refrigeration circuit separate from the circuit of the other units. Each unit includes a housing which defines at least one compartment containing the evaporator of the refrigeration circuit. The condenser is either located in a second compartment in the housing or in a separate chamber associated therewith. A first heat exchange fluid is conveyed to and from the compartment by header pipes the header pipes of adjacent units being interconnected to form common manifolds for the system. A second heat exchange fluid is circulated passed the condensers of each unit. Electrical controls are provided on each unit to control and monitor operation of the respective refrigeration circuit, the controls being interconnected to enable overall control of each unit of the system in accordance with load demand. |