kipperfrog bloghttp://kipperfrog.blog.co.uk/en-EUhourly82000-01-01T12:00+00:00kipperfrog bloghttp://kipperfrog.blog.co.uk/http://data5.blog.de/design/preview/1e/72cef18b0a738ca0b034ddd1b8bb3d_160x200.jpgQuestion19: Give an account of the types of method used to control the thermal environmenthttp://kipperfrog.blog.co.uk/2006/05/09/question19_give_an_account_of_the_types_~786983/2006-05-09T16:06:31+02:00 <p>(a) Passive: adjust surface coating for absorbtivity a & emissivity e to select temperature,T(Kelvin) in solar constant Φ:<br>
Heat in from sun + electronics heat = heat radiated away<br>
a . sunlit area . Φ + electronics heat =e . total surface area .σ .T4<br>
where σ is Stefan Boltzmann radiation constant<br>
(b) Active: (in conjunction with passive)<br>
mechanical shutters change surface finish - ratio of a to e<br>
heat pipes move heat around efficiently<br>
heaters stop liquids from freezing (propellant line/tanks)
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<p> <small> <a href="http://kipperfrog.blog.co.uk/2006/05/09/question19_give_an_account_of_the_types_~786983/#comments">Comments</a> </small> </p>(a) Passive: adjust surface coating for absorbtivity a & emissivity e to select temperature,T(Kelvin) in solar constant Φ:
Heat in from sun + electronics heat = heat radiated away
a . sunlit area . Φ + electronics heat =e . total surface area .σ .T4
where σ is Stefan Boltzmann radiation constant
(b) Active: (in conjunction with passive)
mechanical shutters change surface finish - ratio of a to e
heat pipes move heat around efficiently
heaters stop liquids from freezing (propellant line/tanks)
