The efficiency of photovoltaic (PV) panels is reduced due to the increase of their surface temperature and the presence of hot spots. The non-uniformity of the PV panels not only decreases their efficiency, but also diminishes their life period. In this work, it is investigated the performance of an innovative heat exchanger (HE) with Phase Change Materials (PCM). Simulations were carried out to provide a water flow configuration that reduces and uniformizes the surface temperature of PV panels. The HE was designed with the purpose that commercial PV panels can be easily adapted with the advantage that different types of PCMs can be tested. The cooling provided by the HE allows to investigate the behavior of the PCM during the melting and solidification process. Experiments were carried out to monitor the PV panel surface temperature and the electrical efficiency of the panel with PCM and the HE under different cooling conditions in a semi-arid climate. Results showed a decrease of the average surface temperature up to 14°C and a maximum increase of 71.5% in the average electrical efficiency of the PV panels adapted to this innovative HE with PCM.