| Summary: | In the present study, the evaluation of potential improvement of the overall efficiency of a common PV panel, valorizing the heat extracted by a heat exchanger that is integrated on its back side, either into work using an endoreversible Carnot engine or into cold by using an endoreversible tri-thermal machine consisting of a heat-driven refrigeration machine operating between three temperature sources and sink (such as a liquid/gas absorption machine), was carried out. A simplified thermodynamic analysis of the PV/thermal collector shows that there are two optimal operating temperatures <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mover accent="true"><mi>T</mi><mo>˜</mo></mover><mi>h</mi></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi>T</mi><mi>h</mi><mo>*</mo></msubsup></mrow></semantics></math></inline-formula> of the panels, which maximize either the thermal exergy or the overall exergy of the PV panel, respectively. The cold produced by the endoreversible tri-thermal machine during the operating conditions of the PV/thermal collector at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mover accent="true"><mi>T</mi><mo>˜</mo></mover><mi>h</mi></msub></mrow></semantics></math></inline-formula> is higher with a coefficient of performance (COP) of 0.24 thanks to the higher heat recovery potential. In the case of using the cold produced by a tri-thermal machine to actively cool of an additional PV panel in order to increase its electrical performances, the operating conditions at the optimal temperature <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi>T</mi><mi>h</mi><mo>*</mo></msubsup></mrow></semantics></math></inline-formula> provide a larger and more stable gain: the gain is about 12.2% compared with the conventional PV panel when the operating temperature of the second cooled panel varies from 15 to 35 °C.
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