I can't find anything on relative efficiencies of solar hot water system that faces away from the equator (i.e. south). I'm in Brisbane.
I'm putting in a solar PV system on a north-facing roof. For various reasons I can't have a solar hot water system on anything except a south facing roof. I want to consider the relative costs and benefits of having a plain electric storage water heater that will be driven from the PV system during the day, vs heat pump and the different kinds of solar hot water systems, but I can't find anything that tells you how much efficiency you sacrifice with a south facing solar hot water system. Obviously the up front cost of an electric storage system will be lowest, but it will draw from the grid for a bit over half of the day.
Does anyone know of a calculator or have experience with the various kinds of south facing solar hot water systems, in Brisbane? How much is each kind of system going to draw from the grid in an average day if it is south facing?