Design of an Automatic Control Algorithm for Energy-Efficient ...
Design of an Automatic Control Algorithm for Energy-Efficient ...
Design of an Automatic Control Algorithm for Energy-Efficient ...
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2 <strong>Control</strong> objectives 9<br />
� Metabolism [���] (���� � ��� �� �<br />
�� , sitting calm)<br />
� External work [���]<br />
� �<br />
� ���<br />
� ��<br />
� ��<br />
� �<br />
� ��<br />
� ��<br />
� ���<br />
Water vapour pressure [��]<br />
Air temperature [℃]<br />
Ratio <strong>of</strong> the surface area <strong>of</strong> the clothed body to the surface area <strong>of</strong> the<br />
nude body [-]<br />
Surface temperature <strong>of</strong> the clothing [℃]<br />
Me<strong>an</strong> radi<strong>an</strong>t temperature [℃]<br />
Convective heat tr<strong>an</strong>sfer coefficient [ �<br />
�� ¡� ]<br />
Thermal resist<strong>an</strong>ce <strong>of</strong> clothing [���] (���� � ����� �� ¡�<br />
� )<br />
Relative air velocity [ �<br />
� ]<br />
2.2.2 Inhomogeneous climate<br />
The model by F<strong>an</strong>ger was developed <strong>for</strong> stationary environmental conditions. It gives no<br />
me<strong>an</strong>s <strong>of</strong> including the influence <strong>of</strong> different temperatures <strong>an</strong>d air flows on the body.<br />
A more complex approach is used in the ISO st<strong>an</strong>dard 14505-2 [9] by measuring<br />
temperatures <strong>of</strong> body parts. A com<strong>for</strong>t function chart found in these experiments is given<br />
<strong>for</strong> a winter <strong>an</strong>d a summer case. It is found that a cooler temperature in the head area<br />
is desired, while warm feet lead to maximum com<strong>for</strong>t, especially with cooler ambient<br />
temperatures. This is opposed to the natural air layering where the warmer <strong>an</strong>d lighter<br />
air is on top.<br />
<strong>Control</strong>ling this online would require a lot <strong>of</strong> sensors <strong>an</strong>d actors. There<strong>for</strong>e, this<br />
is usually implemented in hardware in a car HVAC-system. The air flow is optimised in<br />
such way that warm air is output through the foot <strong>an</strong>d defrost outlets, while cooler air<br />
is going directly to the passenger. M<strong>an</strong>ual adaption <strong>of</strong> the direct air flow temperature is<br />
sometimes implemented. Since this is related to the hardware, the temperature layering<br />
will not be regarded further in this work.<br />
The air flow itself c<strong>an</strong> also cause discom<strong>for</strong>t. Higher air speed on the body leads to<br />
higher heat tr<strong>an</strong>sfer coefficients <strong>an</strong>d consequently to <strong>an</strong> intensified temperature sensation.<br />
The effect <strong>of</strong> moving air with ambient temperature is included in the com<strong>for</strong>t calculation<br />
in equation 2.6. Local air jets with a different temperature, however, as they occur in a
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