Course : UNDERSTANDING THE BASICS OF REFRIGERATION Lesson 5 VOLUMETRIC EFFICIENCY OF A RECIPROCATING COMPRESSOR Presented By: Harshit Aggarwal

ABOUT ME Graduated from NIT Nagpur in 2008 . Cleared Indian Engineering Services (IES-UPSC) Exam . Got the offer letter from most of the Maharatna and Navratna Companies Cleared GATE Exanmm Course fee: CONTRIBUTE . Follow me on Unacademy at: https://unacademy.in/user/harshit_aggarwal

VOLUMETRIC EFFICIENCY OF A RECIPROCATING COMPRESSOR COMPRESSION CYCLE: Entering +Compression + Leaving (1 cycle--> 1 revolution) .It is defined as the ratio of the swept volume. . If m is actual mass flow rate of refrigerant and vi is specific volume of the refrigerant at the inlet of compressor, then actual volume of refrigerant entering the compressor = my, kg/sec x m3/kg = m3/sec actual vo wept

. We know that swept volume, D2L / cycle but every cycle is completed in 1 revolution therefore Napm Ncycle/min N. XN cycle- D2LN ; D= Diameter of cylinder, L= stroke min length . If there are k number of cylinders or compressor, total swept volume= D2LNk .n.ol =TD2LNk mv. (D = Bore diameter/ Piston diameter)

Volumetric of a reciprocating compressor is also given by ,-I + C-C ( 2) 1/n , P, = Pressure at compressor inlet, P2-pressure at compressor outlet, n = index of expansion -mvo Clewenceo olume= Clearance Volumev . Clearance Ratio or Clearance Factor, C = Swept Volume

NUMERICAL . In a simple VC Cycle, following are the properties of refrigerant at various point compressor inlet h 183.2 kJ/kg, vi 0.0767 m3/kg, compressor discharge h- 222.6 kl/kg, v,-0.06 14 m3/kg, condenser exit h3_h,-84.9 kJ/kg, v,-0.00083 m3/kg. The piston displacement volume is 1.5L and its volumetric is 80%. Speed N = 1600rpm. Find 1) Power input to compressor in kW 2) RE in kW. Sol: P=m(h2-hi) 0.8 =-m2:0.0767 m3 m = 0.417 kg/sec P = 0.417 (222.6-183.2) P = 16.43 kw RE = 0.417 (1832-849) RE = 40.9 kw . 1.5 x 10-3x160 sec 60 V, = 1.5 Litre = 1.5 x 10-3 m3 mv 4

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Harshit Aggarwal

Cleared UPSC ESE twice with Rank 63 and 90 in mechanical engg. Got 99 percentile in GATE. Cracked ONGC, BHEL,ISRO, SAIL, GAIL successfully

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Vinusha alluri

8 months ago

good but very few forms. need to explain more

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Abhilash devarakonda

2 years ago

thanq sooo much sir

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Abhilash devarakonda

2 years ago

thanq sooo much sir

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Vishal Kukka

3 years ago

sir keep the vapour absoprtion cycle

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Harshit Aggarwal

3 years ago

OK

DIWAKAR CHAURASIA

3 years ago

Please suggest me for IES

Vishal Kukka

a year ago

what should i suggest you about a coaching means unacademy videos far most better than coaching
i can suggest you coaching centre also MADE EASY DELHI sorry for the late reply @diwakar

ANOOP KUMAR

3 years ago

why we take complete length of cylinder in swept volume ...there is some clearance b/w piston and cylinder head

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Amit Phoenix

3 years ago

L is not the length of the whole cylinder.
L is the stroke length, which makes it swept volume and not the whole volume of the cylinder.

Harshit Aggarwal

3 years ago

We have not considered the clearance volume. L is the stroke length that is why it is stroke volume.

Pankaj Sharma

3 years ago

if the mass flow rate of the regrigerant is decreasing from chiller what will the effect on the different parameters of chiller?

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Harshit Aggarwal

3 years ago

I will make lesson on that