制冷系统选型计算

制冷系统选型计算,,,,,,,

,,,,,,,计算结果输出

,,,,,,,已知输入

一、设计工况,,,,,,,查表

代号,名称,取值说明,设计值,单位,,,经验值

Tw,车外环境温度,设计环境,35.00,℃,,,

φw,车外相对湿度,,50.00%,--,,,

Tn,车内环境温度,舒适要求,27.00,℃,,,

φn,车内相对湿度,,50.00%,--,,,

Tk,冷凝温度,,63.00,℃,,,

Te,蒸发温度,,0.00,℃,,,

Pk,冷凝压力,查表,1803.90,kPa,,,

Pe,蒸发压力,查表,292.82,kPa,,,

△T1,冷凝过冷度,经验取值,5.00,℃,,,

△T2,蒸发过热度,经验取值,5.00,℃,,,

△T3,吸气过热度,经验取值,5.00,℃,,,

T前,节流膨胀阀前温度,T前=Tk-△T1,58.00,℃,,,

T1,蒸发器出口温度,T1=Te+△T2,5.00,℃,,,

Ts,压缩机吸气温度,Ts=Te出+△T3,10.00,℃,,,

n,压缩机额定转速,选型假定,1800.00,rpm,,,

△Ps,吸气管路压阻,经验取值,67.26,kPa,,,

△Pd,排气管路压阻,经验取值,81.00,kPa,,,

Q,汽车计算热负荷,,3916.190,W,,,

Qe，s,制冷系统所需制冷量,Qe=1.1*Q,4307.809,W,,,

二、压缩机选型计算--压缩机额定工况,,,,,,,

Pd,压缩机排气压力,Pd=Pk+△Pd,1884.90,kPa,,,

Ps,压缩机吸气压力,Ps=Pe-△Ps,225.56,kPa,,,

hs,压缩机吸气比焓,根据Ps和ts查表,407.952,kJ/kg,,,

υs,压缩机吸气比体积,,0.0989,m3/kg,,,

ss,压缩机吸气比熵,,1.782,kJ/kg/K,,,

hds,压缩机等比熵压缩终了的制冷剂比焓,根据Ps和ss查表,455.813,kJ/kg,,,

ηi,额定空调工况下压缩机的指示效率,ηi=（Te+273.15）/（Tc+273.15）+bTe,0.813,--,,,

hd,额定工况下压缩机的排气比焓,hd=hs+（hds—hs）/ηi,466.852,kJ/kg,,,

Td,额定工况下压缩机的排气温度,根据Pd和hd查表,87.100,℃,,,

h5,蒸发器进口制冷剂比焓,根据T前查表,279.312,kJ/kg,,,

h1,蒸发器出口制冷剂比焓,根据t1和Pe查表,404.4,kJ/kg,,,

"qe,s",蒸发器的单位制冷量,"qe,s=h1—h5",125.088,kJ/kg,,,

"qm,s",额定空调工况下制冷系统所需制冷剂的单位质量流量,"qm,s=

Qe,s/

qe,s/1000",0.034438227,kg/s,,,

"qe,c",额定空调工况下压缩机的单位质量制冷量,"qe,c=h1—h5",125.088,kJ/kg,,,

"qv,c",额定空调工况下压缩机的单位体积制冷量,"qv,c=

qe,c/υs",1264.613705,kJ/m3,,,

"qm,c",额定空调工况压缩机的制冷剂质量流量,"qm,c=qm,s",0.034438227,kg/s,,,

"Qe,c",额定空调工况压缩机所需制冷量,"Qe,c=

qe,c×qm,c",4.308,kW,,,

二、压缩机选型计算--压缩机额定工况转换成测试工况（方便选型）,,,,,,,

"制冷剂冷凝温度tc,t=60℃;制冷剂的蒸发温度te,t=5℃;膨胀阀前制冷剂液体过冷度△tsc,t=0℃;压缩机的吸气温度ts,t=t1/=20℃;压缩机的转速n=1800r/min;压缩机吸气管路压降△PS=67.26Kpa;压缩机排气管路的压降△Pd=81Kpa",,,,,,,

,,,,,,,,

Pk，t,测试工况冷凝压力,查表,1681.30,kPa,,,

Pe，t,测试工况蒸发压力,查表,349.63,kPa,,,

Pd，t,测试工况压缩机排气压力,Pd=Pk+△Pd,1762.30,kPa,,,

Ps，t,测试工况压缩机吸气压力,Ps=Pe-△Ps,282.37,kPa,,,

hs，t,测试工况压缩机吸气比焓,根据Ps和ts查表,415.833,kJ/kg,,,

υs，t,测试工况压缩机吸气比体积,,0.0795,m3/kg,,,

ss，t,测试工况压缩机吸气比熵,,1.791,kJ/kg/K,,,

t4，t,测试工况膨胀阀前制冷剂液体温度,"t4=tc,t—△tsc,t",60.000,℃,,,

h4，t,测试工况膨胀阀前制冷剂液体比焓,"根据t4,t查表",287.397,kJ/kg,,,

qe.t,测试工况压缩机的单位质量制冷量,qe.t=hs.t—h4，t,128.436,kJ/kg,,,

"qv,t",测试工况压缩机单位体积制冷量,"qv,t=qe，t/υs，t",1615.872,kJ/m3,,,

,两种工况下输气系数相等λt=λc,λt=λc,,,,,

"Qe,t",测试工况下压缩机所需制冷量,"Qe,t=Qe,c(λt/λc）",4.308,kW,,,

"qm,t",测试工况压缩机所需制冷剂单位质量流量,"qm,t=Qe,t/qe,t",0.034,kg/s,,,

"hd,t",压缩机等比熵压缩终了的制冷剂比焓,"根据Pd,t和Ss,t查表",458.190,kJ/kg,,,

"td,t","制冷剂温度td,s",,85.940,℃,,,

"Wts,t",测试工况下压缩机单位等比熵压缩功,"Wts,t=hd,t—hs,t",42.357,kJ/kg,,,

"Pts,t",测试工况下压缩机的理论等比熵功率,"Pts,t=

Wts,t•qm,t",1.421,kW,,,

ηi，t,测试工况压缩机指示效率,ηi=（Te，t+273.15）/（Tc，t+273.15）+bTe，t,0.845,--,,,

"Pi,t","测试工况压缩机指示功率Pi,t","Pi,t=

Pts,t/ηi,t",1.681,kW,,,

"Pm,t","测试工况下压缩机摩擦功率Pm,t","Pm,t=1.3089D2SinPm×10-5",0.260,kW,,,

"Pe,t","测试工况下压缩机所需轴功率Pe,t","Pe,t=

Pi,t

+Pm,t",1.941,kW,,,

"根据压缩机的转速n的指定值和Qe,t，Pe,t，qm,t的计算结果粗选择压缩机的型号",,,,,,,

三、压缩机选型计算--选型压缩机实际参数（对比选型）,,,,,,,

,压缩机型号SE5H14,,,,,,

qvt,压缩机理论排量,,138.000,cm3/r,,,

n,压缩机转速,,1800.000,rpm,,,

qvth,每小时压缩机理论输气量,qvth=qvt×n×60/1000000,14.904,m3/h,,,

λ,压缩机的输气系数,,0.720,--,,,

qvr,实际排气量,qvr=λ•qvth,10.731,m3/h,,,

标况下,,,,,,,

υ1,比体积,,0.069,m3/Kg,,,

h1,,,413.2,kJ/kg,,,

h2s,,,443.5,kJ/kg,,,

h3/,,,279.3,kJ/kg,,,

qmr,压缩机的质量流量,qmr=qvr/υ1,154.7351118,Kg/h,,,

Qe,实际循环制冷量Qe,Qe=qm（h1—h3）/3600,5.755286518,kW,,,

Pe,压缩机的功率Pe,Pe=qmr（h2s—h1）/(3600ηiηm),1.814874383,kW,,,

,,ηi—指示效率

取0.78,0.78,--,,,

,,ηm—机械效率

取0.92,0.92,--,,,

ε,实际制冷系数ε,ε=Qe/Pe,3.171176238,--,,,

四、节流膨胀阀参考选型,,,,,,,

"qe,s",额定工况蒸发器单位质量制冷量,"qe,s=h1—h5",125.088,kJ/kg,,,

"qm,s",额定空调工况下制冷系统所需制冷剂的单位质量流量,"qm,s=

Qe,s/

qe,s/1000",0.034438227,kg/s,,,

"qm,v",膨胀阀制冷剂选型流量,"qm,v大于或等于系统流量",0.035,kg/s,,,

"Qm,v","膨胀阀容量Qm,v","Qm,v=qm,v*qe,s",4.37808,kW,,,

,"膨胀阀容量Qm,v可化为冷吨","Qm,v/0.8/3.517",1.556,USRT,,,

五、蒸发器参考选型,,,,,,,

Q0,蒸发器容量,"Q0=qe,s*qm,s",4.307809,kW,,,

,选型参考,取整值,4.5,kW,,,

六、冷凝器参考选型,,,,,,,

Qk,冷凝器