Vapour compression cycle

VAPOUR COMPRESSION CYCLE R & AC

Name:- Nirmal A LuhanaRoll No:- EC – 48Enrollment No:- 140170111050Branch:- Electronics & CommunicationDivision :- IClass :- B.E. 1st SemesterCollege:- Vishwakarma Govt. Engg. College

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VAPOR-COMPRESSION REFRIGERATION CYCLE

►There are four principal control volumes involving these components:►Evaporator►Compressor►Condenser►Expansion valve

►Most common refrigeration cycle in use today

All energy transfers by work and heat are taken as positive in the directions of the arrows on the schematic and energy balances are written accordingly.

Two-phaseliquid-vapor mixture


Process 4-1: two-phase liquid-vapor mixture of refrigerant is evaporated through heat transfer from the refrigerated space.Process 1-2: vapor refrigerant is compressed to a relatively high temperature and pressure requiring work input.Process 2-3: vapor refrigerant condenses to liquid through heat transfer to the cooler surroundings.Process 3-4: liquid refrigerant expands to the evaporator pressure.

►The processes of this cycle are

Two-phaseliquid-vapor mixture


►Engineering model:►Each component is analyzed as a control volume at steady state.►Dry compression is presumed: the refrigerant is a vapor. ►The compressor operates adiabatically.►The refrigerant expanding through the valve undergoes a throttling process.►Kinetic and potential energy changes are ignored.

Evaporator


(Eq. 1)

►Applying mass and energy rate balances

►The term is referred to as the refrigeration capacity, expressed in kW in the SI unit system or Btu/h in the English unit system. ►A common alternate unit is the ton of refrigeration which equals 200 Btu/min or about 211 kJ/min.

41in hhmQ

inQ

CompressorAssuming

adiabatic compression

Condenser

Expansion valveAssuming a

throttling process


12c hhmW

34 hh

(Eq. 3)

(Eq. 4)

(Eq. 2)

►Applying mass and energy rate balances

32out hhmQ

Coefficient of Performance (COP)


(Eq. 6)

(Eq. 5)

►Performance parameters

Carnot Coefficient of Performance

This equation represents the maximum theoretical coefficient of performance of any refrigeration cycle operating between cold and hot regions at TC and TH, respectively.

P-H DIAGRAM► The pressure-enthalpy (p-h) diagram is a thermodynamic

property diagram commonly used in the refrigeration field.

VAPOR-COMPRESSION AIR CONDITIONING CYCLE

• An air conditioning system is an assembly of different part of the system used produce a specified condition of air within a require space or building.

• The basic elements of air conditioning system:--• Fans : For circulation of air• Filters : For cleaning air• Heating Elements : Heating of air(It may be electric heater , steam

, hot water.• Control System : It regulates automatically the amount of cooling

or heating.• Grill : It adjust the direction of the conditioned air to the room.• Tray : It collects condensed water.• Refrigerating Plant : provide cooling . It consist of

compressor/generator and absorber, evaporator, condenser, expansion device(capallary tube).

Air Conditioning System

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Types Of Air Conditioner

• Window Air Conditioner• Split Air Conditioners

Vapor-Compression Air Conditioning Cycle

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Window Air Conditioner

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Window Air Conditioner Working:--The air circulation system of the window air conditioner comprises of

the following parts. 1) Blower: This is the small blower that is fitted behind the evaporator or cooling coil

inside the assembly of the window air conditioner system. The blower sucks the air from the room which first passes over the air filter and gets filtered. The air then passes over the cooling coil and gets chilled. The blower then blows this filtered and chilled air, which passes through the supply air compartment inside the window air conditioner assembly. This air is then delivered into the room from the supply air grill of the front panel.

2) Propeller fan or the condenser fan: The condenser fan is the forced draft type of propeller fan that sucks the atmospheric air and blows it over the condenser. The hot refrigerant inside the condenser gives up the heat to the atmospheric air and its temperature reduces.

3) Fan motor: The motor inside the window air conditioner assembly is located between the condenser and the evaporator coil. It has double shaft on one side of which the blower is fitted and on the other side the condenser fan is fitted. This makes the whole assembly of the blower, the condenser fan and the motor highly compact.

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Split Air Conditioner

SPLIT AIR CONDITIONER The Split Air Conditioner divided in two parts:-- (1)First part:-Include the evaporator ,filter,

evaporator fan and grill. They placed inside the room.

(2)Second part:-Include Condenser ,fan,compressor.This placed out side the room. diameter tubes.

therefore, small hole required in wall of installation of split air condition. The split air conditioning units are available in capacity range of 1 to 3 tons.

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Vapour compression cycle

Engineering

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