The vacuum insulates heat of water, the water in space (11) namely the water in solar hot water cylinder is heated under the irradiating and heating of solar light and the insulating of vacuum.

Solar panels are compatible with most hot water systems, although you may need a cylinder big enough to hold two days' worth of hot water.

Thereby the purpose of the water in high-temperature reflecting hot water cylinder namely in space is heated by solar light irradiating.