These are systems in which heating and cooling is conducted locally, these systems are relatively common in schools, small hotels, domestic applications, residential homes and small offices. The following table will show a comparison between theseĭecentralized Systems (Individual Room Systems) Combined (Hybrid) Water and Air Systems.
Centralized Fluid Based Hydronic Systems.Centralized Ducted “All – Air” Systems.Centralized systems (Central Hydronic systems): This can be divided to three major types as follows:.Two pieces systems (ducted Split system).Packaged Air Conditioners with Air Cooled Condensers.Packaged Air Conditioners with Water Cooled Condenser.One piece systems (Unitary Packaged Systems):.Semi- centralized systems (packaged systems): This can be divided to two major types as follows:.Mini-Split Cooling Units (ductless split Units).Decentralized Systems (Individual Room Systems): This can be divided to three major types as.The air-conditioning components and equipments may be designed and assembled in hundred different ways but in practice these are broadly classified into three categories: On the next page, we’ll look at how the different parts of an air conditioner work to make all that possible. Refrigerant is chilling the indoor air, and the resulting gas is being continually compressed and cooled for conversion back to a liquid again. It’s easy to see that there are two distinct things going on in an air conditioner. Think of it as an endless, elegant cycle: liquid refrigerant, phase conversion to a gas/ heat absorption, compression and phase transition back to a liquid again. As the gas cools, it changes back to a liquid, and the process starts all over again. All the extra heat created by compressing the gas is then evacuated to the outdoors with the help of a second set of coils called condenser coils, and a second fan. To do that, a compressor puts the gas under high pressure, a process that creates unwanted heat.
To keep cooling efficiently, the air conditioner has to convert the refrigerant gas back to a liquid again. When hot air flows over the cold, low-pressure evaporator coils, the refrigerant inside absorbs heat as it changes from a liquid to a gaseous state. In fact, central air conditioners have a whole system of ducts designed to funnel air to and from these serpentine, air-chilling coils. Air conditioners also contain fans that move warm interior air over these cold, refrigerant-filled coils. The compounds involved are refrigerants that have properties enabling them to change at relatively low temperatures. Air conditioners exploit this feature of phase conversion by forcing special chemical compounds to evaporate and condense over and over again in a closed system of coils. Air conditioners use refrigeration to chill indoor air, taking advantage of a remarkable physical law: When a liquid converts to a gas (in a process called phase conversion), it absorbs heat.
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