Cycle Analysis cond Condenser 3 2 Throttling Compressor Valve 4 1 Evaporator T-s diagram? p-h diagram? subcooling TA △Tsc 2 P Tcond -3--- --TH Pcond Tevap ·T Pevap superheat::△Tsh h S 上游充通大 May9,2019 6 SHANGHAI JIAO TONG UNIVERSITY
May 9, 2019 6 Cycle Analysis P h 3 2 4 1 pcond pevap s T 2 1 3 4 Tcond Tevap TH TL subcooling Tsc superheat: Tsh Compressor Throttling Valve Condenser 1 3 2 4 Evaporator W Qcond Qevap T-s diagram? p-h diagram?
Cycle Analysis Typical Assumptions specified evaporating(Tevap)and condensing (Tcond) temperatures specified superheat entering the compressor specified subcooling leaving the condenser ● constant pressure throughout heat exchangers negligible kinetic and potential energy changes for all components ● adiabatic throttling valve specified isentropic efficiency for compressor adiabatic compressor 上游充通大 May9,2019 7 SHANGHAI JLAO TONG UNIVERSITY
May 9, 2019 7 Cycle Analysis Typical Assumptions • specified evaporating (Tevap) and condensing (Tcond) temperatures • specified superheat entering the compressor • specified subcooling leaving the condenser • constant pressure throughout heat exchangers • negligible kinetic and potential energy changes for all components • adiabatic throttling valve • specified isentropic efficiency for compressor • adiabatic compressor
Cycle Analysis Compressor Inlet State P1=Pevap h1=h(Tevap+ATsh Pevap Compressor Outlet State P2 =Pcond T◆ isentropic 32-p specific work Tcond h2 =h,+has h) ns Tevap isentropic efficiency S h2s=h(p2,S2=S1) 图 上游充通大 May9,2019 8 SHANGHAI JLAO TONG UNIVERSITY
May 9, 2019 8 Cycle Analysis Compressor Inlet State p1 = pevap h1 = h (Tevap+Tsh , pevap) Compressor Outlet State p2 = pcond h2s = h (p2 , s2 = s1 ) isentropic specific work 2s 1 2 1 s isentropic efficiency (h h ) h h T s 2 Tcond Tevap p2 1 2s
Cycle Analysis Condenser Outlet State P 3 P3=Pcond 444444444444444 h3=h (Tcond+ATse,Pcond) negative Pevap Evaporator Inlet State P4 Pevap h h4=h3 上游充通大学 May9,2019 9 SHANGHAI JLAO TONG UNIVERSITY
May 9, 2019 9 Cycle Analysis Condenser Outlet State p3 = pcond h3 = h (Tcond+Tsc , pcond) Evaporator Inlet State p4 = pevap h4 = h3 P h 3 4 Pcond negative Pevap