Refrigeration Air Conditioning - Bangladesh University of...

Refrigeration & Air Conditioning

Refrigeration &

Air Conditioning Aashique Alam Rezwan

Lecturer Dept. of Mechanical Engineering, BUET http://teacher.buet.ac.bd/aashiquear

1 ME, BUET 01/25/14

http://teacher.buet.ac.bd/aashiquear


What is Refrigeration? Artificial withdrawal of heat Producing in a substance or within a

space a temperature lower than that whichwould exist under the natural influence ofthe surrounding

Dehumidifying

2 ME, BUET 01/25/14


What is Air Conditioning? Artificial tampering of the conditions of air

Cooling Heating Ventilation Filtration Air circulation Dehumidifying

3 ME, BUET 01/25/14


Relationship of Ref. & A/C

Heating Humidifying

Food Preservation

Coo

ling

Deh

umid

ifyin

g

Air Conditioning

Refrigeration

4 ME, BUET 01/25/14


Classification of Application Domestic Refrigeration Commercial Refrigeration Industrial Refrigeration Marine & Transportation Refrigeration Comfort Air Conditioning Industrial Air Conditioning

5 ME, BUET 01/25/14


VAPOR COMPRESSION REFRIGERATION

6 ME, BUET 01/25/14


Heat flows from warm space to colder water. Water temperature rises as space temperature decreases. Refrigeration will not be continuous

7 ME, BUET 01/25/14


Heat flows from warm space to cold ice. Temperature of space decreases as ice melts. Temperature of ice remains at 32F (0C). Heat absorbed by ice leaves space in water going out the drain.

8 ME, BUET 01/25/14


The Refrigerant 134a liquid vaporizes as it takes in heat from the 40F space. The heat taken in by the refrigerant leaves the space in the vapor escaping through the vent

9 ME, BUET 01/25/14


The boiling temperature of the liquid refrigerant in the evaporator is controlled by controlling the pressure of the vapor over the liquid with the throttling valve in the vent.

01/25/14ME, BUET 10 ME, BUET


Pressure of refrigerant in evaporator reduced below atmospheric by action of a vapor pump.



Float valve assembly maintains constant liquid level in evaporator. The pressure of the refrigerant is reduced as the refrigerant passes through the needle valve.



Serpentine coil evaporator with thermostatic expansion valve refrigerant control.



14 ME, BUET 01/25/14


Flow diagram of simple vapor compression system showing the principle parts



16 ME, BUET 01/25/14


Key Component of Refrigerator 1. Evaporator2. Suction line3. Vapor compressor4. Hot

gas/discharge line 5. Condenser6. Receiver tank7. Liquid line8. Refrigerant flow

control device

17 ME, BUET 01/25/14


AIR CONDITIONING

18 ME, BUET 01/25/14


Thermal Comfort

Thermal comfort is defined as that conditionof mind which expresses satisfaction with thethermal environment.

19 ME, BUET 01/25/14


Typical Climate Condition

20 ME, BUET 01/25/14


Factors Affecting Thermal Comfort 1. Activity level2. Clothing3. Expectation4. Air temperature5. Radiant temperature6. Humidity7. Air speed

21 ME, BUET 01/25/14


Basic Air Conditioning System

22 ME, BUET 01/25/14


THANK YOU

23 ME, BUET 01/25/14

Refrigeration & Air ConditioningWhat is Refrigeration?What is Refrigeration?What is Refrigeration?What is Air Conditioning?Relationship of Ref. & A/CClassification of ApplicationComfort VS Industrial A/CComfort VS Industrial A/C (cont.)Food Preservation by RefrigerationCommercial/Industrial ApplicationVapor Compression RefrigerationSlide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 18Slide Number 19Slide Number 20Slide Number 21Slide Number 22Key Component of RefrigeratorSlide Number 24RefrigerantRefrigerantIdeal Properties for RefrigerantClassification of RefrigerantNumbering of RefrigerantNumbering of Refrigerant (cont.)Numbering of Other RefrigerantPerformance ParameterAir ConditioningThermal ComfortTypical Climate ConditionFactors Affecting Thermal ComfortBasic Air Conditioning SystemAir Handling UnitWindow Type Air ConditionerSplit SystemAll Air System with ReheatAll Air System with Variable Air VolumeTHANK YOU

Refrigeration Air Conditioning - Bangladesh University of...

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