Bài giảng Chapter 3: Compressor

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Bài giảng Chapter 3: Compressor CHAPTER 3: COMPRESSOR Lecturer : ThS.Nguyễn g y Duyy Tuệ ệ 12/2015 Chapter 3 : Compressor 1 OBJECTIVES Student can: - Understand components and operation principles of some kinds of refrigerant compressor -UUnderstand de s a d thee e effect ec oof working o g co conditions d o s oon compressor’s efficiency 12/2015 Chapter 3 : Compressor 2 REFRERENCE [1]. Trane document - Compressor [1] [2]. Industrial refrigeration handbook – McGraw- Hill ( Chapter 4,5 45) 12/2015 Chapter 3 : Compressor 3 CONTENTS COMPRESSORS TYPES RECIPROCATING COMPRESSOR SREW COMPRESSOR SCROLL COMPRESSOR CENTRIFUGAL COMPRESSOR 12/2015 Chapter 3 : Compressor 4 COMPRESSOR TYPES Reference :(Page ( g 1,[1]) ,[ ]) The purpose of the compressor in a refrigeration y system is: 1/ to raise the p pressure of the refrigerant g vapor from evaporator pressure to condensing pressure. 2/ to remain the p p pressure in evaporator p 12/2015 Chapter 3 : Compressor 5 COMPRESSOR TYPES A review of the refrigeration g cycle, y , using g the pressure–enthalpy chart, will help to illustrate this p point. 12/2015 Chapter 3 : Compressor 6 COMPRESSOR TYPES There are p primarily y four types yp of compressors p used in the air-conditioning industry: reciprocating, scroll,, helical-rotaryy ((or screw), ), and centrifugal. g 12/2015 Chapter 3 : Compressor 7 COMPRESSOR TYPES We also classifyy to three types yp of compressor: p + Hermetic type compressor : 12/2015 Chapter 3 : Compressor 8 COMPRESSOR TYPES + Open p type yp compressor p : 12/2015 Chapter 3 : Compressor 9 COMPRESSOR TYPES + Semi-Hermetic type yp compressor p : 12/2015 Chapter 3 : Compressor 10 RECIPROCATING COMPRESSOR 1. Construction : Reference (p(page g 4,, [[1]) ]) The refrigerant vapor is compressed by a piston y , similar to the engine that is located inside a cylinder, g in an automobile. A fine layer of oil prevents the g refrigerant vapor p from escaping p g through g the mating g surfaces. 12/2015 Chapter 3 : Compressor 11 RECIPROCATING COMPRESSOR The ppiston is connected to the crankshaft byy a rod. As the crankshaft rotates, it causes the piston to y travel back and forth inside the cylinder. This motion is used to draw refrigerant vapor into the cylinder, p compress it,, and discharge g it from the cylinder. y 12/2015 Chapter 3 : Compressor 12 RECIPROCATING COMPRESSOR Crankshaft,, connecting g rod and oil ring g: 12/2015 Chapter 3 : Compressor 13 RECIPROCATING COMPRESSOR A ppair of valves,, the suction valve and the discharge valve, are used to trap the refrigerant p within the cylinder vapor y during g this p process. 12/2015 Chapter 3 : Compressor 14 RECIPROCATING COMPRESSOR Cylindrical valve 12/2015 Chapter 3 : Compressor 15 RECIPROCATING COMPRESSOR During g the intake stroke of the compressor, p , the piston travels away from the discharge valve and creates a vacuum effect,, reducing g the ppressure within the cylinder to below suction pressure. 12/2015 Chapter 3 : Compressor 16 RECIPROCATING COMPRESSOR Duringg the compression p stroke,, the ppiston reverses its direction and travels toward the g valve,, compressing discharge p g the refrigerant g vapor p and increasing the pressure within the cylinder. When the p pressure inside the cylinder y exceeds the suction pressure, the suction valve is forced closed, pp g the refrigerant trapping ...