C6 - Buffer storage system with solar and boiler buffer storage

C6.1 - Buffer storage system with circulation heat exchanger (WT)

C6.2 - Buffer storage system with domestic hot water backup storage and circulation heat exchanger (WT)

The system consists of the following components:

#	Hydraulic Configuration / Components	C6	C6.1	C6.2
1	1 or 2 collector loop(s)	x	x	x
2	Solar buffer tank	x	x	x
	The solar buffer tank is loaded by the solar system, exclusively. If the temperature in the storage tank is high enough, the heating return is raised by discharging the tank. The return from the DHW station is layered over a 3-way reversing valve and dependent on the storage temperature in the solar buffer tank. If the return temperature is too high to discharge the buffer tank, the solar buffer tank is circumvented with a bypass switch and the return from the DHW station is sent directly to the boiler buffer tank.
3	Boiler buffer tank	x	x
	The boiler buffer tank is heated by the boiler only. The therefore more constant temperatures in the boiler buffer tank enable more simple and safer operation of the boiler as well as the drinking water station. The boiler buffer tank is discharged through the DHW station only. The separation of the solar storage tank and the boiler buffer tank can be simply implemented hydraulically and prevents the hot boiler water from mixing with the cooler solar water.
4	DHW standby tank			x
5	Circulation heat exchanger (optional)		x	x
	A circulation heat exchanger heats the DHW. If the temperature in the solar buffer tank allows, then the circulation losses are covered by the solar buffer tank.
6	Valve: Solar inflow		x
	The solar inflow can be switched between the solar buffer tank and the boiler buffer.
7	External heat exchanger at solar buffer tank		x	x
	The solar loop heats the solar buffer tank via an external heat exchanger.
8	Valve: Return flow boost	x	x	x
	The solar buffer tank is discharged by a return flow boost, which is supporting the solar heating.
9	External heat exchanger at solar buffer tank at 2 different temperature levels			x
	The solar loop heats the solar buffer tank via an external heat exchanger. Depending on the current temperature level, the solar heated water is stratified into 2 different heights of the solar buffer tank.
10	Internal heat exchanger in solar buffer tank	x
	The connection to the solar loop is made by the internal heat exchanger in the buffer tank.
11	Auxiliary heating	x
	The auxiliary heating maintains the temperature setting in the boiler buffer tank and supplies the heating loop with the required energy.
12	DHW station, supplied by the boiler buffer tank	x	x
	The return of the DHW station is stratified into the solar buffer tank via a 3-way diverter valve and depends on the tank temperature. If the return temperature of the DHW station is too high to unload the solar buffer tank, this tank can be bypassed via a bypass circuit, and the return of the DHW station goes directly into the boiler buffer.
13	Heat exchanger			x
	The solar buffer tank is discharged via a heat exchanger to preheat the drinking water.
14	The preheated domestic hot water is reheated by the boiler and stored in the DHW standby tank.			x