Solar radiant energy falls on a rectangular black body,

$10m25m0\mathrm{.}005m,$ at a rate of $800\frac{W}{m^2}.$ The body is

provided with two layers of insulation of $30mm$ and $10mm$

thickness, respectively. The thermal conductivities of

the body and the insulations ara $50\frac{W}{m}K,0\mathrm{.}05\frac{W}{m}K$

$(30mm),0\mathrm{.}15\frac{W}{m}K(10$mm$)$ respectively. The inside air

temperature is $20C$ and the inside convective heat trans$-$

fer coefficient is $10\frac{W}{m^2}K.$ The outside air temperature

is $-1C$ and the outside convective heat transfer coeffi$-$

cient is $35\frac{W}{m^2}K.$ The temperature of space is $-20C.$

Determine the heat transfer rate through the body.

ANSWER IS Solar radiant energy falls on a rectangular black body,

$10m25m0\mathrm{.}005m,$ at a rate of $800\frac{W}{m^2}.$ The body is

provided with two layers of insulation of $30mm$ and $10mm$

thickness, respectively. The thermal conductivities of

the body and the insulations ara $50\frac{W}{m}K,0\mathrm{.}05\frac{W}{m}K$

$(30mm),0\mathrm{.}15\frac{W}{m}K(10$mm$)$ respectively. The inside air

temperature is $20C$ and the inside convective heat trans$-$

fer coefficient is $10\frac{W}{m^2}K.$ The outside air temperature

is $-1C$ and the outside convective heat transfer coeffi$-$

cient is $35\frac{W}{m^2}K.$ The temperature of space is $-20C.$

Determine the heat transfer rate through the body. See

Figure $1.$

ANSWER IS $-980$ WATTS