1.Calculate the required area of an air to air heat exchange to cool 20,000 cfm from 1200 F to 400 F. Assume ambient air at 80 F will be heated to 800 F by the exchange. Assume heat losses are 10 % and that the overall heat transfer coefficient is 1.0 Btu/hr-ft^2- °F
2.Argon is expanded in an isentropic turbine from 2 MPa and 500oC to 200 kPa. Determine the outlet temperature and the work produced by this turbine per unit mass of argon.
3.Saturated R-134a vapor enters a compressor at 0 degrees F. At compressor exit, the specific entropy is the same as that at the inlet, and the pressure is 60 psia. Determine the R-134a exit temperature and the change in the enthalpy of R134a.
4.A large steel tower is to be supported by a series of steel wires; it is estimated that the load on each wire will be 19,000N. Determine the minimum required wire diameter assuming a factor of safety 5 and that the yield strength of the steel is 900MPa.