System	Dual coil indirect hot water tank	Solar tank (monovalent)	Buffer tank (bivalent)	Solar buffer tank	Single coil heating buffer tank	DHW standby tank	Combination tank/internal heat exchanger	Auxiliary heating	Heating loop	External heat exchanger	DHW heating	Fresh water station
C1 - Large-scale DHW system with solar and standby tank	x	x	x			2x	x	x	x	x	x
C2 - Large-scale DHW system with standby tank		x	x			x		x	x	x	x
C3 - Large-scale DHW system with standby tank and heat exchanger		x	x			x		x	x	x	x
C4 - Large-scale DHW and space heating system with auxiliary heating in flow		x	x			x	o	x	x	x	x
C6 - Large-scale DHW system with solar and standby storage tank		x / x	x / x					x	x			x
x = available, o = optional

The use of large solar buffer tanks, external heat exchangers, and anti-Legionnaire’s switches is typical for large-scale systems.