Question

1. Fill in the following table for R-134A: T(°F) P (psia) h (Btu/Ibm) Phase 70 150 70 Sat Liquid 108.8 2. What is the pressure inside a 420 L container if it contains 8.5 kg of air at 25 °C? The atmospheric pressure for that day is 97 kPa. 3. 1.8 kg of Nitrogen fills a piston chamber with a volume of 0.038 m’ at 560 kPa gauge. The piston is then moved so that the volume doubles. The chamber is allowed to sit until it again reaches room temperature of 20 °C. What is the final pressure in the chamber?

Answer 1

I ③ P= topsia, h=150 Btu/ebm frow steam table of R134a by pressure at p-topsia => hg = 111.22 Btu/rom hang . R134a exists as super healed yapour from X cannot defined. for superhaulede voupoor. superhealed steam table of R134a at p= topsia, h. 150 Btu/lom T OF h Brullbm) Ma 240 153.21 150 148:39 220 153- 21-150 240-220 153.21-14839 T= 226. 68 OF © To so º p: 70 psia frow Steary table of R134a at p= topsia , Tsat = 58.30 - ... тK Ts- 2 at R134a exista from stani table as Subcooled Aiquid. of R134a by temperature

- at To 50°F » Thang = 28.131 Btu/16m] @ mal @ = -30 °F , satriated liquid no] from saluraled steam table of R134a by temperalore at t= -30°F => 1h=h2= 3.011 Btu/loml (P= P sul = 9.869 psia) T=40°F , h=108.8 (Btu/1km) from saturated steam touble of 2134o. by Хер. at T=40°F => Thg=h=188.8 (Btulism . Risqa existe as saluzaled vapour i [621] TP = Psut = 49.776 psia) @ 9= -30 °F , P= 5 psía frowy steay table of R134a - at p= spsia , T sut =-53.09 °F S T > Tsut R R134a exists as superheuled Vapour a n Not Applicable But in super heated table all the date e available frou P=iopsia. NO duló found forh' P- 5psia & 72-30°F.