Chapter Four: Energy transfer by Heat, Work and Mass
Heat Transfer Mechanisms
Example 1
Example 2
Example 3
Example 4
Example 5
Example 6
Example 7
Example 8 R-134a compressor 2 0.8 MPa 50C 1 0.14 MPa
Refrigerant-134a enters a compressor as a saturated vapor at a specified pressure, and leaves as superheated vapor at a specified rate. The rates of energy transfer by mass into and out of the compressor are to be determined. Assumptions 1 The flow of the refrigerant through the compressor is steady. 2 The kinetic and potential energies are negligible, and thus they are not considered. Properties The enthalpy of refrigerant-134a at the inlet and the exit are (Tables A-12 and A-13)
Analysis Noting that the total energy of a flowing fluid is equal to its enthalpy when the kinetic and potential energies are negligible