Generally there are three kinds of cold rooms: self-contained, remote condensing, and multiplex condensing.
Self-contained coldrooms are cold storage rooms where the refrigeration system is a complete package with the evaporator and condenser built into one unit. The obvious advantage of self contained coldrooms is they are simple to install and can be moved easily from 1 site to another. It is like a domestic refrigerator except on a larger scale. The down side is because the evaporator is built into the unit, it can cause the surrounding environment to be warm and noisy.
Remote condensing unit coldrooms have the condenser unit somewhere other than directly adjacent to the room and not packaged with the evaporator. They are placed on the roof of the building for example. This arrangement allows the hot and often noisy evaporator and condenser unit to be place further away from your business operations and provides a quieter and cooler working environment.
Multiplex coldrooms use a centralized system with multiple condensing units and evaporators. Multiplex walk-ins are always built directly into the buildings they serve.They are often found in huge logistical warehouses.