Hello i am trying to setup an ode45 to solve this differential equation ρaCaVdTin/dT= Qshort − Qconv,cond − Qinfilt where Qshort Qconv and Qinflit are all equations describing the loss or gain of heat in a greenhouse.
What i am trying to achieve is by giving a column vector variable of external temperature wind speed and light intensity i want the ode45 to give me the internal temperature for the corresponding value of external temperature wind speed etc ie i want Tin(1) to come from ode45 which will use the first time value from my tspan the first external temperature etc.
The way i ve coded it by inputting a breakpoint inside the function i ve noticed that from the first execution of my code the internal temperature vector is already a 297×1 column vector same length as my tspan.going past the breakpoint of dT results in an error that the initial conditions vector must have the same number of elements as the vector returned. The question is, is there a way to achieve my intended result which is as i ve stated above for ode45 to use one value of my vectors to get one result? Sorry for my bad english it isn't my first language and thanks in advance.
the error i am getting which is saying that the length of the initial conditions vector needs to be the same length as the returning vector of elements.
I have included the txts from where i am getting the vectors of wind speed external temperature and solar radiation intensity.
What i am trying to achieve (and probably this isnt the right way to achieve ) is for ode45 to use for each of the 297 time variables the corresponding external temperature wind speed etc to create a 297×1 internal temperature model which is Tsol.I ve tried using a steady variable for wind speed external temperature etc and seen that this code works and creates a 297×1 internal temperature model the problem occurs when adding these column vectors as inputs. Is there another way to achieve the intended result?
below i am presenting the code
L=4;W=3.7;H=3;volup=1*(1*4)/2; %ogkos trigwnikhs orofhs
voldown=W*L*2; %ogkos katw or8ogwniou parellhlepipedou
V=voldown+volup; %Sunolikos ogkos
taxythtaaera = importdata('taxythta aera.txt');exwterikh=importdata('metablhtes.txt');ilios=importdata('hlios.txt');S=L*W;Vw=taxythtaaera*0.27777777777778;Tac=15; %8ermokrasia se kelsioy
Ta=exwterikh+273.15; %se kelvin kai 15 se kelsiou kserw gw
Ta(265)=[];Ta(143)=[];Ta(53)=[];Pa=1.137; %air density inside
Ca=1005; %specific heat of air
sta=Pa*Ca*V;ac=0.1; %cover absorbtivity
tc=0.85; %cover transmittance
I=ilios; %kanonika pinakas olikh iliakh aktinobolia w/m^2
Sc=H*W; Tsky= 0.0552.*(Ta.^1.5);Tskyc=Tsky-300;R=0.75; %air changes per hour APO FUSIKO AERISMO
Qshort=ac*tc*S*I;stat=Qshort/sta;stat2=S/sta;stat3=5.2*(R/((Sc*L))^1/2);stat4=R/V;ho=2.8+1.2.*Vw;ho(132)=[];ho(53)=[];ho(274)=[];stat5=((ho*S)/sta)*(1-tc);Kc=0.028; %cover K w*m^-1*k^-1
Lc=0.03; %cover thickness
%dT=Qshort/pa*ca*V-U*(S/Pa*Ca*V)(T-Tout)-(Pa*Ca*R/Pa*Ca*V)*(T-Ti)/3600-(ho*S*(1-tc)/(Pa*Ca*V)(T-Tsky)
t0=0;To=286.15;tend=35640;n=297; %giati allazei toso to apotelesma analoga me ta deigmata? sta 300 fainetai arketa sta8ero
tspan=linspace(t0,tend,n);[tsol,Tsol]=ode45(@(t,T) funcODE(t,T,ho,Ta,I),tspan,To);plot(tsol,Tsol-273.15)function dT= funcODE(t,T,ho,Ta,I)Tout=Ta;ho=ho;I=I;L=4;W=3.7;H=3;volup=1*(1*4)/2; %ogkos trigwnikhs orofhsvoldown=W*L*2; %ogkos katw or8ogwniou parellhlepipedouV=voldown+volup; %Sunolikos ogkosS=L*W;i=1;Pa=1.137; %air density insideCa=1005; %specific heat of airsta=Pa*Ca*V;ac=0.1; %cover absorbtivitytc=0.85; %cover transmittance
Sc=H*W; Tsky= 0.0552.*(Tout.^1.5);R=0.75; %air changes per hour APO FUSIKO AERISMOQshort=ac*tc*S*I;stat=Qshort/sta;stat2=S/sta;stat3=5.2*(R/((Sc*L)^1/2));stat4=R/V; stat5=((ho*S)/sta)*(1-tc);Kc=0.028; %cover K w*m^-1*k^-1Lc=0.03; %cover thicknessU=(1.0714+(1/ho)+(1/(1.52*(T-Tout).^1/3+stat3))).^-1;dT=stat -(((R/(V*3600))*(T-Tout(i)))+(((ho*S*(1-tc))/sta)*(T-Tsky(i)))+(S*(T-Tout(i))*U(i)));i=i+1;
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