Page 367 - Defrosting for Air Source Heat Pump

Appendices 363

PwSat_Air=exp(-5800.2206*Tair.^(-1)+1.3914993*Tair.^(0)-
0.04860239*Tair.^(1)+0.000041764768*Tair.^(2)-0.000000014452093
*Tair.^(3)+6.5459673*log(Tair));% Pa
dens_air=0.80*PwSat_Air/(8314/18*(273.15+0));% relative_Humi_air
=0.80;
% 0.0039 density of component outside boundary layer, kg/m 3
% PwSat_pipeAir(1,t)=Pressure_Air_Water(Tr(1,t))
% dens_pipe(c,t)=Pressure_Air_Water(Tw(c,t-1)).*10^6./
(8314./18.*(273.15+Tw(c,t-1)))
% density of gas at interface (saturation density), kg/m 3
T=Tri(j,i)+273.15; % K
denspipe=exp(-5800.2206*T.^(-1)+1.3914993*T.^(0)-
0.04860239*T.^(1)+0.000041764768*T.^(2)-0.000000014452093*T.^(3)
+6.5459673*log(T))/(8314./18.*T); % calculate the density of humid-
ity air, kg/m 3
kTri=Tri(j,i); % °C
2
kRr=Rr(j,i); (K˙m )/W
kMr=Mr(j,i); % kg/s
khri=hri(j,i); % kJ/kg
% all the input parameters in the function listed here
x0=[0.0042 0.0042 0.335 1200 0.001];
options=optimset(’display’,’off’,’MaxIter’,10000,
’MaxFunEvals’,20000); % number
[A,fval,exit]=fsolve(@(x) mystage43(x,kTw1,mr0,smvaw,i,
denspipe,dens_air,kTri,kRr,kMr,khri),x0,options);
mrw(j,i)=A(1); % retained water, kg/s
mvaw(j,i)=A(2); % vaporized water, kg/s
Tw(j,i)=A(3); % retained water temperature, °C
qr(j,i)=A(4); % energy used in defrosting from refrigerant, W
Tro(j,i)=A(5); % the temperature of tube surface at exit of
each circuit, °C

A
x00=real(A);
fval
exit
2
hair(j,i)=1.4748.*Tri(j,1).^(1/3); % W/(K m )
qair(j,i)=1.4748.*Tri(j,1).^(4/3).*2.6852*2.5*2; % W
s_qair(j,i)=sum(qair(:,i))*5; % W
2
hd(j,i)=hair(j,i)/1005./1.258./0.845^(2/3); % W/(K m )
smvaw(j,i)=5.*sum(mvaw(:,i)); % kg
qm(j,i)=334000.*mf(j,i); % W
qvap(j,i)=mvaw(j,i)*2443*1000; % W
s_qvap(j,i)=sum(qvap(:,i))*5; % W
watertray(j,i)=0; % kg/s
swatertray(j,i)=sum(watertray(:,i)); % kg