1. If you have an existing hot water tank this will need to be replaced with a twin coil cylinder. This will be for your hot water supply as normal. A second tank, a direct cylinder, with a larger volume of possibly up to 3 times your existing capacity, will be required. The solar fraction will be taken into account on both these cylinders, even though you would not require the heating tank during the summer. The heating tank also works as our heat dump. We would divide the heating up, as explained in zoned heating, using the additional pumps and add an extra radiator in the bathroom area. During winter we already have stored our hot water in the direct cylinder so when the heating starts, you are potentally starting the heating at 75 - 80° which makes it more efficient. The tanks can be prioritised for your requirements during the year, and we would educate you so you can apply the settings yourself.
2. The alternative is to have a large thermal store (buffer tank) using fresh hot water modules and stratification units. This is a cheaper option for new build. It can be incorporated into the building much easier as the diameter of the tank range from 750mm to 2000 mm wide.