The solar hot water circuit will automatically be created by the software when the heating circuit is set up with a solar hot water tank. You can not add the circuit manually on this page.
To model solar hot water panels you can either draw them in the geometry and make sure a solar gain surface output specification has been applied to the surface facing the sun, or you can enter details about the solar panels without having included them in the geometry. If you've added the panels to the geometry then the surface output specification will be applied when you are adding the building data in the TBD.
The former approach will require you to set the Calculation Method box to Use Zone Surface. This box will automatically be set if you copy one or more surfaces onto the solar hot water circuit. Otherwise set it to Specify Values and input the inclination, orientation, solar reflectance, and surface area of the panel. These options only exist when there are no surfaces on the circuit itself.
The difference in accuracy between the methods will likely be small; self-shading and ground solar reflectance will not be modelled by the "specify values" calculation method.
Hourly solar gain absorbed by the panel surfaces will be used in the calculations for both methods.
Exercise and Notes
In this example we will be using the "use zone surface" approach because we've already drawn in the panels in the 3D Modeller. Drag the surface onto the circuit. The calculation method will be set accordingly so you don't have to change this.
The design flow rate will be 0.2 l/s per m2, which is a typical flow rate for solar hot water.
Maximum panel efficiency and heat loss coefficients are as per the image shown above.