Chapter_11 - Chapter 11 11-12 An ideal vapor-compression...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 11 11-12 An ideal vapor-compression refrigeration cycle with refrigerant-134a as the working fluid is considered. The COP and the power requirement are to be determined. Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible. Analysis In an ideal vapor-compression refrigeration cycle, the compression process is isentropic, the refrigerant enters the compressor as a saturated vapor at the evaporator pressure, and leaves the condenser as saturated liquid at the condenser pressure. From the refrigerant tables (Tables A-11, A- 12, and A-13), ) throttling ( kJ/kg 32 . 107 kJ/kg 32 . 107 liquid sat. MPa 1 kJ/kg 29 . 275 MPa 1 K kJ/kg 92927 . kJ/kg 77 . 252 vapor sat. C 4 3 4 MPa 1 @ 3 3 2 1 2 2 C 4 @ 1 C 4 @ 1 1 h h h h P h s s P s s h h T f g g The mass flow rate of the refrigerant is kg/s 750 . 2 kJ/kg 107.32) (252.77 kJ/s 400 ) ( 4 1 4 1 h h Q m h h m Q L L The power requirement is kW 61.93 kJ/kg 252.77) 29 kg/s)(275. 750 . 2 ( ) ( 1 2 in h h m W The COP of the refrigerator is determined from its definition, 6.46 kW 61.93 kW 400 COP in R W Q L 11-19 A refrigerator with refrigerant-134a as the working fluid is considered. The rate of heat removal from the refrigerated space, the power input to the compressor, the isentropic efficiency of...
View Full Document

Page1 / 4

Chapter_11 - Chapter 11 11-12 An ideal vapor-compression...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online