SECOND LAW OF THERMODYNAMICS Thermodynamics W p actual = (H_out - H_in)_actual (1-32) _actual= (h_out - h_in)_actual (1-33) w_p m Pump efficiency, , is defined as the ratio of the work required by the pump if it were an ideal h p pump w p, ideal to the actual work required by the pump w p, actual . (1-34) h p W p,  ideal W p,  actual Example: A pump operating at 75% efficiency has an inlet specific enthalpy of 200 Btu/lbm.   The exit  specific  enthalpy  of  the  ideal  pump  is  600  Btu/lbm.    What  is  the  exit  specific enthalpy of the actual pump? Solution: Using Equation 1-34: h p w p,  ideal w p,  actual w p,  actual w p,  ideal h p (h_out h_in)_actual (h_out h_in)_ideal h p h out,  actual (h_out h_in)_ideal h p h in,  actual h out,  actual (600  Btu/lbm 200  Btu/lbm) .75 200  Btu/lbm h out, actual = 533.3 Btu/lbm + 200 Btu/lbm h out, actual = 733.3 Btu/lbm HT-01 Page 82 Rev. 0