Experimental Case Study - Design for Micro-Combined Cooling, Heating and Power Systems - page 364

Fig. 15 Functional electric diagram of the experimental mCCHP system [ 17 ]

Possibility of charging the batteries from several alternative current sources
(network, generator, beside PV panel) by automatic switches between these
different sources;

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Reliability in the overvoltage and over current presence (overvoltage and over
current protections);

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Allows parallel connection for extend to three phase.

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The functional electrical diagram of the experimental mCCHP system is shown
in Fig. 15 .

8.1.2 Thermal Subsystem Components

First, the ST panel and back-up boiler must be dimensioned. After that, the
hydraulics and the pumps will be dimensioned. The third source is the Stirling
engine which was dimensioned in electrical subsystem. The Stirling engine has an
internal cooling system with a pump and expansion vessel, and a plate heat
exchanger. The second circuit which makes connection between the plate heat
exchanger and the storage tank (outer system) must be dimensioned. The ow rate

in the outer system (aided by the pump which runs continuously when the CHP is
operating) is 1 2m 3 /h, resulting in a spread of 20

K at maximum load. Finally,
will be dimensioned the heat storage tank and the expansion tank. All hydraulic
circuits must be protected at over temperature and pressure.

- - 10 °

A. Solar thermal panel

The starting data for sizing the ST panel include the speci c ST production in the

month with the biggest PV production (July) and the medium sunshine time cor-
responding to the same month.