Can't comment on a thermal collector, but if we look at efficiency of solar PV and heat pumps: Solar PV panel: the best ones are up to about 22% efficiency. He

Can't comment on a thermal collector, but if we look at efficiency of solar PV and heat pumps: Solar PV panel: the best ones are up to about 22% efficiency. Heat pumps: again, top of the line approaches 400% You can't just multiply those numbers, however, there's also losses when you invert DC to AC, but it might be a good starting point.