Question

Please use EES only.

In a produce chilling system, air is cooled by being passed over a heat exchanger coil througlh which R-134a flows steadily at a rate of 15 lbm/min. Prior to entering the heat exchanger coil, the refrigerant passes through a throttling valve as shown in the figure below. The R-134a enters the valve as a saturated liquid at high pressure (which will be varied) and leaves at 35 psia. The refrigerant leaves the heat exchanger coil as a saturated vapor at 35 psia. Air enters the heat exchanger at 14.7 psia and 50°F and leaves at 35°F. Determine the effect of varying the refrigerant pressure at the inlet to the throttling valve from 125 to 250 psia on the volumetric flow rate of the air (in ft3/min) at the inlet to the heat exchanger and on the quality of the refrigerant entering the heat exchanger. Use the EES fluid properties function menu to obtain all thermodynamic properties needed including quality of the R-134a and specific volume of air. Create a parametric table showing the R-134a inlet pressure, volumetric flow rate of air at the inlet to the heat exchanger, and quality of the R-134a leaving the throttling valve. Plot the volumetric air flow rate and R-134a quality against R-134a inlet pressure on x-y plots. Print the following to turn in 1. 2. 3. 4. 5. Your name, date, and EES HW 3 (as a comment on the first line of your program) Equations (as typed, not formatted) Parametric table Each plot with a description (title) Brief discussion (enclose in quotes or braces at end of program) of your observations about the effect of R-134a inlet pressure on each of the variables plotted Throttling valve Saturated R-134a quid Saturated R-134a vapor

Answer 1

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