Rooftop photovoltaic power station Rooftop photovoltaic power station A rooftop photovoltaic power station, or rooftop PV system, is a photovoltaic system that has its electricity-generating solar panels mounted on the rooftop of a residential or commercial building or structure. The various components of such a system include photovoltaic modules, mounting systems, cables, solar inverters and other electrical accessories. Rooftop mounted systems are small compared to ground-mounted photovoltaic power stations with capacities in the megawatt range. Rooftop PV systems on residential buildings typically feature a capacity of about 5 to 20 kilowatts (kW), while those mounted on commercial buildings often reach 100 kilowatts or more.
Injective module group Q/Z and the circle group are also injective Z-modules. The factor group Z/"nZ for "n" > 1 is injective as a Z/"nZ-module, but "not" injective as an abelian group. More generally, for any integral domain "R" with field of fractions "K", the "R"-module "K" is an injective "R"-module, and indeed the smallest injective "R"-module containing "R". For any Dedekind domain, the quotient module "K"/"R" is also injective, and its indecomposable summands are the localizations formula_1 for the nonzero prime ideals formula_2. The zero ideal is also prime and corresponds to the injective "K". In this way there is a