汽车空调热负荷计算及选型算例(共6页).doc

精选优质文档-倾情为你奉上Example:一、M -Vehicle Key information Survey for Air conditionSheet 1: Vehicle Key information Survey1.Vehicle: Max Passenger (driver included) ：5 persons Inner volume space：3.8m32 Glass Windshield : Materials： White+PVB Width：4mm Areas：1.06m2 Conduction coefficient： 6.4 Transmission rate：0.7 L-front window： Materials： Green Width：3.2mm Areas：0.33m2 Conduction coefficient：6.4 Transmission rate：0.7 R-front window: Materials：Green Width： 3.2mm Areas：0.33m2 Conduction coefficient：6.4 Transmission rate：0.7 L-rear window: Materials：Green Width： 3.2mm Areas：0.28m2 Conduction coefficient：6.4 Transmission rate：0.7 R-rear window: Materials：Green Width： 3.2mm Areas：0.28m2 Conduction coefficient：6.4 Transmission rate：0.7 Black window : Materials：Green Width： 3.2mm Areas：0.78m2 Conduction coefficient：6.4 Transmission rate：0.73 Roof panel Roof outside: Materials： DC04 Width： 0.7mm Areas: 1.85m2 Conduction coefficient：484 Roof Roof inside: Materials: PE+PU Width： 2mm Areas：1.85m2 Conduction coefficient：0.045 Base : Materials： PU+GF Width：4.7mm Areas：1.85m2 Conduction coefficient：0.05 Roof Back: Materials： PET Width：0.5mm Areas：1.85m2 Conduction coefficient：0.055 Floor Front floor: Materials： DC04 Width： 0.8mm Areas：0.949m2 Conduction coefficient：48 Middle floor: Materials： DC04 Width： 0.7mm Areas：0.921m2 Conduction coefficient：48 Rear floor: Materials： DC04 Width： 0.7mm Areas：1.322m2 Conduction coefficient：48 Central floor: Materials： DC04 Width： 1.2mm Areas：0.688m2 Conduction coefficient：48 Damper cushion: Materials： spin felt Width： 20mm Areas： 2.26m2 Conduction coefficient：0.05 Carpet: Materials：PETEVA Width： 5mm Areas： 2.26m2 Conduction coefficient：0.056 Firewall Dash panel Materials: B180H1 Width：1.2mm Areas： 1.17m2 Conduction coefficient：48 Outside damper Materials：Al-foilPET GFPET Width：25mm Areas：0.75 m2 Conduction coefficient：0.045 Inside damper Materials: EVAPU Width：25mm Areas：0.295m2 Conduction coefficient：0.05 In- down damper Materials: EVAPU Width：25mm Areas：0.737 m2 Conduction coefficient：0.057Side body Outside Materials： DC04 Width： 0.7 mm Areas：1.4m2 Conduction coefficient：48 Inside Materials：B340/590DP /B340LA Width： 1.5 mm Areas：1.4m2 Conduction coefficient：48 Inside trim Materials： PP-T20 Width： 2.5 mm Areas：1.4m2 Conduction coefficient：0.058.Door Outside Materials：B180H1 Width： 0.7 mm Areas：2.81m2 Conduction coefficient：48 Inside Materials： DC04 Width： 0.8 mm Areas：2.81m2 Conduction coefficient：48 Inside trim Materials：ABSPVC PP+EPDM-T20 Width：3mm Areas：2.81m2 Conduction coefficient：0.05备注：Conduction coefficient单位为：w/m2.k二、Air Conditioning Performance Setting2.1 Test procedure： 4 person， 40km/h（60min）-idle(20min)90km/h(20min)， Other specification can refer to standards2.2 AC target setting according to SOR, Sheet2：Time (min)Average of breath levelAverage of Air outlets332 17 52814202394522760227802813100217三、Refrigerant Heat load Computation3.1 Some data needed in computation3.1.1、Surface area，sheet 3:No.ItemsSurface（m2）NotesFront 1.061 GlassRear0.78Side1.222Roof1.853Side body1.44door2.815cowl1.173.1.2、Conditions for Air condition： Outside Temp：40（ Test procedure） Target Average breath level：22（Items included in SOR） Vehicle speed：40km/h3.2 Calculation stepsAir condition refrigerant Heat load can be divided into two parts, one is Temperature difference load ,the other one is humidity load.3.2.1 Temperature difference load1、Sun load In the presence of Solar radiation, part of the heat is absorbed by the glass, part of the solar radiation transmitted through the glass, and the rest of them is be reflected. The glass absorbs the solar heat and heat transfer from the outside high air temperature, All these will results in glass Temperature heat transfer. And the heat transmission through the glass will be storage in vehicle body or trims ,it will transfer the heat in a slow way .In this calculation, all that solar radiation heat transfer into vehicle is assumed to be quick transient load . So ,QGlassA Tk+MAC( qb) and：AAll glass surface area，take it as 3.06 m2 Ttb-ti ( tb is the synthesis temperature of glass，considering the poor heat storage of the glass We can take the transfer coefficient as G(Z)=1, so we can take tb as 40；ti is Average target breath level Temp in cabin .ti22) Ksynthesis heat transfer coefficient，we can take it as 6.4w/m2.k , m Non single glass adjust number，we choose 1.0 CSolar shelter adjust number，we take 1.0 MGlass Area Coefficient ,consider the Angle we will take it as 0.8 for front and back window， and side window take it as 0.5 qb Solar intense transfers into monolayer glass qbg I g +s I s+t I g, specular solar load, take it as 1000w； I s，Diffuse solar load ,take it as 100w g specular solar load transmitted rate, take it as 0.7； sDiffuse solar load transmitted rate，take it as 0.08 QsolarA T*k+M*A*C( qb) 3.06*（40-22）*6.40.8*（1.060.78）+0.5*1.22*1.0*（1000*0.70100*0.08） 352.5+1474.1 =1826.6（w）2、Air leakage heat load (fresh air) Q new air l0* n*( h0 -hi) n persons，n=5 l0New air volume for one person per hour，we can set it as 11m3/h per person （Should more than 10 m3/(h.person） in A/C Guideline manual） Air density，取1.14kg/m3 h 0 Outside Air enthalpy h iCabin air Average enthalpy If we assume the humidity is both 50% of inside air and of outside air ,then using Graph H-D ,we can get hi=43kJ/kg ,h0=99kJ/kg, Actually we can use any humidity number ,just for simple calculation . so ,Q new air l0* n*( h0 -hi) 11*5/3600*1.14*(99-43)*1000=975.3w3、Body heat load Q 车身KF(tm-ti) KVehicle body synthesis heat transfer coefficient，it is decided by next:+=（Notes：Besides firewall and floor other body s tm can be taken as body Temp） tm, ti tm The equivalent Temp of exterior body，ti Air Temp in cabin Sum of conduction heat transfer for all layer（i width for layers，i conduction for layer） cabin convection heat transfer coefficient，when the velocity is less than 3m/s .we can take it as 29 w/m2.k Outside convection heat transfer coefficient，1.163（12×0.5 + 4)， is air velocity outside of the vehicle，if =40 km/h，then 51.2w/m2.k(1) RoofKa- roof heat transfer coefficientRoof -layersOutside layerAir layersurfacebasebackWidth(mm)0.72024.70.5Conduction coefficient w/m2.K480.110.0450.050.05=0.33 =2.604 Fa- Surface of Roof it is 1.85m2 tm- Equivalent Temp of Roof ,According to our Experience ,we can take it as 80 ti Temp.of cabin Air flow QRoofKaF(tm-ti) =2.604*1.85*(80-22)=279.41(2) Side bodyKb- Side body heat transfer coefficientSide -layersOutside layerAir layerInner layerInner trimWidth(mm)0.7701.52.5Conduction coefficient w/m2.K480.4480.05=0.23 =3.52 Fb- Surface of side body it is 1.4m2 tm- Equivalent Temp of Side Body,According to our Experience ,we can take it as 60 ti Temp.of cabin Air flow Q sideKbFbt 3.52×1.4×（60-22） =187.3（w）(3) DoorKc- Door heat transfer coefficientDoor -layersOutside layerAir layerInner layerInner trimWidth(mm)0.71100.83Conduction coefficient w/m2.K480.63480.05=0.24=3.4 Fc- Surface of side body it is 2.81m2tm- Equivalent Temp of Door,According to our Experience ,we can take it as 60 ti Temp.of cabin Air flowQ sideKcFct 3.4×2.81×（60-22） =363.1（w）(4) FloorKd- Floor heat transfer coefficientFloor -layersOutside layerDampercushionWidth(mm)0.7205Conduction coefficient w/m2.K480.050.05=0.5 =1.81 Fd- Surface of Floor it is 3.88m2 tm- Equivalent Temp of Floor, According to our Experience ,we can compute by a formula ti Temp.of cabin Air flow tm= t0+ =40+ =46.83 Q floorKdFdt 1.81×3.88×（48.33-22） =174.38（w）Considering the exhaust pipes heat radiation, we will take extra 200w for the influence. Q floor374.38w(5) FirewallKe- Firewall heat transfer coefficientFirewall -layersOutside DamperDash panelInside DamperWidth(mm)251.225Conduction coefficient w/m2.K0.045480.05=1.05 =0.91 tm- Equivalent Temp of Firewall, According to our Experience ,we can take it equal 90 ti Temp.of cabin Air flow As considering the different K values in upper and down side of the firewall .we may need to divided into two parts one is upper firewall. the other one is down firewall. Fe- upper Surface of firewall is 0.75m2 Fe- lower Surface of firewall is 0.42m2 - upper heat transfer of the firewall is 0.91w/m2k- lower heat transfer of the firewall is 1.87w/m2kQ upperKeFet 0.91×0.75×（90-22） 46.41（w） Q lowerKeFet 1.87×0.42×（90-22） 53.4 Q firewallQupper+ Q lower99.81（w） So. All the heat which has been transferred from body is Q bodyQ roofQ sideQ doorQ floorQfirewall 279.4+187.3+363.1+374.38+99.81 1303.99（w）=1304(w)4、Human heat load5 persons， 1 driver， 4 passengers ,we can refer to the A/C guide manualQ drive170w, Q passenger108W, And the crowded code =0.89故 QhumanQ dirvern * Q passenger* =170+4×0.89×108 554.5（w）5、Heat load from Equipment, illumination QEquipment =100w3.2.2 Air conditioning humidity heat load（1） when the cabin temperature has reached into 22，And humans humidity loss rate is about d0=45g/h ,so ,all together all humidity loss is D0n*d0=5×45225g/h（2）Vehicle inner cabin volume is setting to 3.8m3, SO , All air in cabin is about m= air *v=1.14×3.84.3（kg） (3)if we assume our blower volume L0 is 450m3/h, then ,we can get the number for the percentage humidity in airD d= D0×（V/ L0）÷m =225×（3.8/450）÷4.3 =0.44(g/kg)Refer to H-D Drawing，H1.35KJ/kg Q humidity =1.35×103×（450*1.14/3600） 192（w）3.2.3 Air conditioning heat load (All-together) Q= Q solar+Q new air+ Q body+ Q person+ Q equipment+ Q humidity =1826.6+975.3+1304+554.5+100+192 =4952.4（W）Considering the 10% discount for A/C Design Margin,so, Q4952.4×1.1=5447.64（w）5.45(kw)专心-专注-专业