Implementing the mathematical model into a computer program

In order to reduce the time necessary to identify the best fitting surface and to ensure that the method is applied by all users in the same way the mathematical extrapolation procedure has been implemented into a Microsoft Excel based computer program named DHWScale.

For the solar domestic hot water system(s) of the product line that have/has been tested with the DST — method the following inputs have to be entered in the Excel sheet:

• For each tested system of the product line

— Collector area

— Storage tank volume

— Solar fraction fsol

• Number of systems tested from the product line

• Location (only Athens available up to now)

• Daily hot water consumption

With these data the program automatically computes the best fitting surface for the specific location and hot water consumption. When the corresponding surface is known the solar fraction can be computed for arbitrary sizes of collector area and storage tank volume.