One advantage of this system is that almost no water is introduced into the tank separated tank feature:

Heat exchanger inside the tank which provides more than 1.2m2 of heat transfer area. When water flows though the coil it absorbs heat from the water inside the solar collector tank. The solar collector tank is therefore a thermal store.

One advantage of this system is that almost no water is introduced into the tank(apart from occasional topping up), so corrosion and scale buildup are almost totally eliminated.