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is packaged and unitary are both same system ? and split system is categorized in unitary system or central system?
Both are same
Package as name indicates comes as a package with both cool and hot part together can be water or air cooled and normally comes in bigger capacities like more than15 TR and have single thermostat control and always have ducted connection which is serving may be bigger area or different zones.
Unitary system as name indicates used for unit or single area normally comes in small capacities and cooling can be done by either way. Can be multi split or VRV type and can be classified into many types.
Both of them rely on DX source. However, they are different in the aspect of the location of cooling plant, i.e. the compressor.
1) An unitary system shall be dedicated to a single space with refrigerant piping from the plant to the air-side equipment. An unitary system can be used to serve many spaces with FCU or AHU having ducting distributed to multiple zones. A advanced version of an unitary system shall be VRF system that are capable of serving multiple spaces with smart & sophisticated control (with refnet branching).
2) A packaged unit on the hand is a single housing that has the compressor within the package; hence limited refrigerant piping. The supply duct emerges out from one end of the packaged unit & routes through the shafts or opening till the spaces or zones to be served; the return comes from the same spaces back to the packaged unit completing a recirculation. A reasonable proportion of fresh air is induced through the return path for comfort condition.
Packaged and unitary are both same system but the siting of a packaged unit is more critical than that of separate plant, since all components are together, and a compromise may have to be reached between the convenience of having the unit close to the load and the difficulty of obtaining condenser air or water, transmitting extra noise, or creating new safety aspects.
Unitary system means a system which combines heating, cooling, and fan sections all in one(Packaged) or a few assemblies(Split). Package Unit and Split systems can be used as unitary system and centralized system. Consider for a substation, a large capacity packaged unit can be used as unitary system. The same packaged unit can be used to supply for two or three separate areas with or without terminal controls.
