Question

A refrigeration unit compresses 0.65 kg / s of refrigerant saturated 134a steam at 18 ° C up to 1000 kPa. Determine:

the adiabatic compressor power required, in kW, if its isentropic efficiency is 85%.

Answer 1

mass flow rate= m = 0.65 Givengr Rafsigirant Rizua kg is initial conclitions zo saturated steam at 1-18°C final condicions - 100 Olpa > isentoopie eficiency 2=0.85-857 2) t-s diagram of compression processes to8 쁜 1000kpa → 2 538-374kpa а) ерчь enthalphy at state 18c hii uos-66 kJ/kg g 2) entropy at stake i 5,= Sg'= 1.7188 kJ/1ogik 2) Icleally 1185 z) s, -52 =) 1-2 is i sentropic compression So at colin [I at 1000kpa 2)! 1.7188 = 1-1396 in L z T 314.5K 2) enthalphy at & 314-5 t is The = użlo385 kJ/kg = 1.711256 t 39.359 4273 1000 FPa

» Ideal compression bovikW.: hechi e) toc = U21-385- 408.66 2) We 120725. KJ(K9 4 Wc e) Wc اعدا e) accorcling. 40 70i centropic efficiency 120725 = 14.97 kJ/1kg 0.85 2) actual.compression woork Twai = 14097 LT/ 27 Total compression won قرا = wiano : 14093x0-65 -> Achial compressor é 9.73 kW work a Wa