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 14<br />
pumps or fuel heaters are more efficient options when it comes to power consumption.<br />
A fuel heater only needs electric power <strong>for</strong> the ignition process <strong>an</strong>d <strong>for</strong> its f<strong>an</strong>.<br />
During the ignition around ��� � c<strong>an</strong> be drawn from the power supply. Once started<br />
the consumption is quite low. The fuel consumption <strong>for</strong> such small heaters are around<br />
� ���� �¡�� . However, a reservoir <strong>for</strong> the fuel has to be provided.<br />
A heat pump is basically working like a refrigeration circuit, but with the possibility<br />
to heat the passenger compartment as well. As heat sources not only the ambient air c<strong>an</strong><br />
be used, but also internal components like the battery pack or the electric motor. A<br />
detailed description <strong>of</strong> the functioning is found in section 3.3. The adv<strong>an</strong>tage <strong>of</strong> this<br />
solution is that it does not need a separate energy source like fuel. In addition, nowadays’<br />
st<strong>an</strong>dard <strong>of</strong> heating <strong>an</strong>d cooling (<strong>an</strong>d thereby dehumidification) c<strong>an</strong> be combined in one<br />
system. On the other h<strong>an</strong>d, the electric energy consumption will be higher th<strong>an</strong> a fuel<br />
based solution. The power dem<strong>an</strong>d is dependent on the components (e.g. the compressor)<br />
<strong>an</strong>d on the temperature level <strong>of</strong> the heat source/sink <strong>an</strong>d the desired output temperature.<br />
One critical point concerning the use <strong>of</strong> a heat pump in a car is icing <strong>of</strong> the front heat<br />
exch<strong>an</strong>ger (evaporator) when heating in winter. This leads to a dramatically decreased<br />
efficiency down to a point where the refriger<strong>an</strong>t circuit does not work <strong>an</strong>ymore.<br />
Typically there are no sensors measuring the power consumption <strong>of</strong> the components,<br />
but since they are directly controlled the current c<strong>an</strong> be estimated. The components’<br />
consumption has to be measured once <strong>an</strong>d then these values are used.<br />
When the energy is consumed is also <strong>an</strong> import<strong>an</strong>t fact in <strong>an</strong> electric car. There<br />
might be situations, when it is good to consume as much as possible, <strong>for</strong> example when<br />
the battery is fully charged, but the car is recuperating. On the other h<strong>an</strong>d when the<br />
car is short on electric power or the connection to the high voltage system fails, only the<br />
current absolutely necessary may be drawn. In general the power consumption should be<br />
minimised while providing a maximum com<strong>for</strong>t, but this is dependent on the cars energy<br />
overall situation.
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