Solar panels, photovoltaic solar panels and photovoltaic solar panels are all the same thing. They all make up a single panel that can produce electricity.
Solar water heaters are used to dry water. The double-layer vacuum water pipe is filled with water. When sunlight passes through the glass tube and hits the water, the water temperature increases. a double-layer vacuum tube, heat cannot pass through. The vacuum dissipates, so the water becomes warmer and warmer, which can be used for bathing at night, even if the sun is weak in winter, it can still be heated.