there are two different programs to design photovoltaic systems:
if you want to design a thermal solar panel like water heating systems, Tsol by valentine is the best one.
these programs only focus on solar energy and the electricity or heat they produce. if you want to design a building with PV systems you can use another program like DesignBuilder(energyplus).
Are there other programs to do the same process for designing PV, thermal and building energy consumption?