Question $26(3$ points$)$

A $10m^3$ spherical seasonal thermal storage tank filled with water is connected to an

array of solar collectors. Calculate the maximum permissible thermal transmittance to

ensure that the water temperature does not drop more than $10C$ over $30$ days.

Assume that the initial temperature of the water in the tank is $70C.$ Assume that the

tank is buried in ground and is contact with soil at $10C.$ Specific heat of water is $4\mathrm{.}2$

$k\frac{J}{k}gC.$ Density of water is $1000k\frac{g}{m^3}.$

$0\mathrm{.}04\frac{W}{m^{2\text{@}}}C$

$0\mathrm{.}01\frac{W}{m^{2\text{@}}}C$

$0\mathrm{.}16\frac{W}{m^{2\text{@}}}C$

$0\mathrm{.}13\frac{W}{m^{2\text{@}}}C$

$0\mathrm{.}10\frac{W}{m^{2\text{@}}}C$

$0\mathrm{.}07\frac{W}{m^{2\text{@}}}C$

$0\mathrm{.}19\frac{W}{m^{2\text{@}}}C$