They include insulation, improved absorber surfaces, fans to regulate the flow of air and other capacitors like water, like in the water Trombe-wall.
(They; include; insulation) (fans; to regulate; the flow of air and other capacitors like water, like in the water Trombe-wall)
They fans
include to regulate
insulation
the flow of air and other capacitors like water, like in the water Trombe-wall