Saturated steam flows in the annulus of a single effect evaporator at a gauge pressure of $125$kPa. The outer evaporator tube is made of carbon steel and I.D$.=120mm,$ O$.$D$.($:$=130(mm)\}.$ It is lagged with a $10mm$ thickness of kapok $($keapok $=0\mathrm{.}0346W{m}^{-1}{C}^{-1})$ and $15mm$ thick layer magnesia $(k_{\text{m}\text{a}\text{g}\text{n}\text{e}\text{s}\text{i}\text{a}}=0\mathrm{.}233W{m}^{-1}{C}^{-1}.$

If the temperature of the lagging in contact with air is $37C,$ determine the heat loss from the lagged evaporator tube.

Refer to the Steam Tables in Appendix $1.$