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Design of an Automatic Control Algorithm for Energy-Efficient ...

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8 System <strong>an</strong>d functionality integration 77<br />

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Figure 8.4: Comparison <strong>of</strong> the com<strong>for</strong>t temperatures <strong>for</strong> different clothing adaptions.<br />

As <strong>an</strong> option <strong>for</strong> the controller, the parameters (upper <strong>an</strong>d lower clothes insulation) c<strong>an</strong><br />

be adapted to the desired behaviour.<br />

The metabolism value is used to let the user influence the temperature. This is<br />

a good choice since its magnitude is highly dependent on the person. Even if single<br />

values are given in EN ISO 7730 [7], these are only me<strong>an</strong> values. In <strong>an</strong> <strong>an</strong>notation it<br />

is already mentioned there that elderly people have lower metabolisms. Moreover, a<br />

wom<strong>an</strong>’s energy consumption is calculated differently from a m<strong>an</strong>’s. Other parameters<br />

in the Harris-Benedict-Formula, used to estimate the metabolism, are age, weight <strong>an</strong>d<br />

body size [37]. By simulations metabolisms from ���� ��� to ���� ��� have been found<br />

as a suitable r<strong>an</strong>ge. Ch<strong>an</strong>ging this value represents <strong>an</strong> indirect me<strong>an</strong>s <strong>of</strong> controlling the<br />

cabin temperature <strong>an</strong>d c<strong>an</strong> be used to m<strong>an</strong>ually compensate possible errors made in other<br />

parameters. A lower value will automatically lead to a higher com<strong>for</strong>t temperature. An<br />

adv<strong>an</strong>tage <strong>of</strong> this kind <strong>of</strong> user control is that the com<strong>for</strong>t temperature is automatically<br />

adapted to the ambient temperature <strong>an</strong>d the air flow. A scaling with 100 being ���� ���<br />

<strong>an</strong>d 0 equalling ���� ��� is done in order to obtain a simpler scale <strong>an</strong>d the relation <strong>of</strong> a<br />

higher value leading to a higher temperature.<br />

Me<strong>an</strong> radi<strong>an</strong>t temperature<br />

The me<strong>an</strong> radi<strong>an</strong>t temperature � � also has to be estimated. It is approximated by the<br />

me<strong>an</strong> surface temperature <strong>of</strong> the surrounding environment. In a car a major part <strong>of</strong> it is

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