For Viessmann, Phoenix Design designed a high-performance vacuum tube collector for on-roof mounting. The Vitosol 300-T is aimed at maximum set-up and service friendliness and was conceived first of all for highly efficient systems working under limited surface space conditions. The housing color has been matched to the absorber surface, so that the collector blends in with the architecture. The soft curvature of the absorber housing creates a flowing transition between tubes and roof, and it features a slightly serrated structure. This helps section the volume, making it visually less obtrusive.