HVAC

HVACBy Tushar MistryB.E. Mechanical

H HeatingV VentilatingA AirC - Conditioning

What are we Going to Learn?Basics of refrigeration & HVAC Working cycles of HVAC Components of HVAC Functions of HVAC components Study Of Compressor & Condenser Study of Evaporator & Refrigerants Refrigerant handling and replacement Inspection & Breakdown Maintenance Malls, Hotel, Multiplex, Inspection & Breakdown Maintenance

What is the purpose of HVAC ? It conditions the air, transports it, and introduces it to the conditioned space. It provides heating and cooling from its central plant . It also controls and maintains the temperature, humidity, air movement, air cleanliness, sound level, and pressure differential in a space within predetermined limits for the comfort and health of the occupants of the conditioned space or for the purpose of product processing.

What is TR?1 TR is amount of heat required to melt one metric ton of ice in 24 hours. 1 TR (Ton of Refrigeration) = 12000 BTU / hr 1 TR (Ton of Refrigeration) = 3024 Kcal / hr 1 TR (Ton of Refrigeration) = 3.51 KW

H - HeatingHeat is a form of energyMolecules in motionFlows from a substance with more heat to one with less heatUnit = Joule (J) W = J/S = N.M/S

Sensible Heat & latent HeatSensible Heat If heat added or removed from substance , it changes it temperature then its called as sensible heat.

Latent Heat If heat is added or removed it changes the state of substance then its called as latent heat.

Heat Transfer ModesConduction

Convection

Radiation

Specific Heat Amount of heat required to change a unit mass of substance by one degree temperature.

Saturation Temperature Temperature for corresponding saturation pressure at which the liquid boils into its vapour phase.

Enthalpy Total heat content of the system

V - Ventilation

A AirC - Conditioning An air conditioning, or HVAC, system is composed of components and equipment arranged in sequence to condition the air, to transport it to the conditioned space, and to control the indoor environmental parameters of a specific space within required limits.

Basic Refrigeration Cycle

Classification of Air Conditioning SystemAccording to Application 1) Comfort Air Conditioning Systems 2) Process Air Conditioning SystemsAccording to Construction & Operating Characteristics

HVACsystems

Floor Mounted Package Air ConditionPackage Air ConditioningCeiling Mounted Package Air ConditioningDuct able ACDirect Expansion SystemCentral Air Conditioning

Indirect Expansion System

Non Duct able AC

Split Air Condition

Cascade Split AC (Ceiling Mounted)

Floor Mounted Split AC

Wall Mounted Split AC

Window Air Condition15

Windows Air Conditioning System Window air conditioners are one of the most commonly used and cheapest type of air conditioners.To install one of these units, you need the space to make a slot in the wall, and there should also be some open space behind the wall.Window air-conditioner units are reliable and simple-to-install solution to keep a room cool while avoiding the costly construction of a central air system.Better yet, when the summer heat dies down, these units can be easily removed for storage, and you can use the window sill for other purpose

Split Air-Conditioning System The split air conditioner comprises of two parts: the outdoor unit and the indoor unitThe outdoor unit, fitted outside the room, houses components like the compressor, condenser and expansion valve.The indoor unit comprises the evaporator or cooling coil and the cooling fan. For this unit you dont have to make any slot in the wall of the room.Further, the present day split units have aesthetic looks and add to the beauty of the room. The split air conditioner can be used to cool one or two rooms

Central AC SystemThe central air conditioning plants or the systems are used when large buildings, hotels, theaters, airports, shopping malls etc. are to be air conditioned completely.The window and split air conditioners are used for single rooms or small office spaces.If the whole building is to be cooled it is not economically viable to put window or split air conditioner in each and every room.Further, these small units cannot satisfactorily cool the large halls, auditoriums, receptions areas etc.

Air System (AHU)Water SystemCentral PlantControl System

Packaged AC SystemThe window and split air conditioners are usually used for the small air conditioning capacities up to 5 tons.The central air conditioning systems are used for where the cooling loads extend beyond 20 tons.The packaged air conditioners are used for the cooling capacities in between these two extremes.The packaged air conditioners are available in the fixed rated capacities of 3,5, 7, 10 and 15 tons.These units are used commonly in places like restaurants, telephone exchanges, homes, small halls, etc.

POTENTIALS AND CHALLENGESProviding a Healthy and Comfortable Indoor EnvironmentThe Cleanest, Quietest, and Most Precise and Humid Processing EnvironmentEnergy Use and Energy EfficiencyEnvironmental ProblemsCFCs and Global Warming

Goals of HVAC SystemEffectively control indoor environmental parameters, usually to keep temperature and humidity within required limits.Provide an adequate amount of outdoor ventilation air and an acceptable indoor air quality.Use energy-efficient equipment and HVAC&R systems.Minimize ozone depletion and the global warming effect.Select cost-effective components and systems.Ensure proper maintenance, easy after-hour access, and necessary fire protection and smoke control systems.

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