A cold storage unit incorporates a refrigeration system to maintain the desired room environment for the commodities to be stored. A refrigeration system works on two principles:
Vapour absorption system (VAS),
Vapour compression system (VCS)
VAS, although comparatively costlier, is quite economical in operation and adequately compensates the higher initial investment.
VCS is comparatively cheaper than VAS. There are three types of VCS systems available depending upon the cooling arrangements in the storage rooms i.e., diffuser type, bunker type and fin coil type. Diffuser type is comparatively costlier and is selected only when the storage room heights are low.