Reference no: EM132587670
Problem 1 - Refrigerant-134a enters a 28-cm-diameter pipe steadily at 200 kPa and 20oC with a velocity of 5 m/s. The refrigerant gains heat as it flows and leaves the pipe at 180 kPa at 40oC.
(a) Draw a sketch of the process and clearly indicate the control volume.
(b) Determine the mass flow rate (kg/s) of the refrigerant.
(c) Determine the velocity (m/s) at the exit.
Problem 2 - Refrigerant-134a enters an adiabatic compressor as saturated vapor at -24oC and leaves at 0.8 MPa and 60oC. The mass flow rate of the refrigerant is 1.2 kg/s.
(a) Draw a sketch of the process and clearly indicate the control volume.
(b) list your assumptions for working this problem.
(c) Determine the power input (kW) to the compressor.
Problem 3 - Refrigerant-134a enters the throttling valve of a refrigeration system at 120 psia as a saturated liquid and leaves at 20 psia.
(a) Draw a sketch of the process and clearly indicate the control volume.
(b) Determine the temperature change (oF) across the value.
(c) Determine the internal energy change (Btu/Ibm) across the value.
Problem 4 - A heat exchanger is to heat water (Cp = 4.18 kJ/kg.oC) from 25oC to 60oC at a rate of 0.2 kg/s. The heating is to be accomplished by geothermal water (Cp = 4.31 kJ/kgoC) available at 140oC at a mass flow rate of 0.3 kg/s.
(a) Draw a sketch of the process and clearly indicate the control volume.
(b) Determine the rate of heat transfer (kW) in the heat exchanger.
(c) Find the exit temperature (oC) of geothermal water.