As flat roofs;

• offer flexible possibilities for proper orientation and inclination,

• has less possibility of shadowing,

• mostly has large surface area,

• has proper conditions for easy maintenance, repair and access,

• allows to economical solutions,

they are the building surfaces where the system usage and the problem is mostly seen. When forming individual or central systems on flat roofs, the sufficiency of the roof for system application (form, dimension, building envelope and structure characteristics, etc.) and efficacy of the roof on architectural expression are the important issues that have to be apprehended and associated. From this point of view, for adequate usage of solar hot water systems on roofs, the basic topic of a design process that can be fallowed can be organized like,

1. Detailed analysis of the roof;

• Solar access

• orientation,

• Shadowing (roof elements, environmental effects, etc.)

• Physical properties,

• Form and size (dimensions);

• Specifications of roof components, (chimneys, stairs, top covers, windows, etc.

• Technical properties,

• structure,

• envelope section

• Architecture,

• effectiveness in architecture expression,

• association with the whole of the building

• aesthetic perception

2. Decision on the system form to be used on roof;

• Invisible, building component / central, individual, etc.

3. Calculations of efficiency, sizing the system and defining the system components,

4. Decision on the collector and tank areas;

5. Formation (designing) of these areas

• Ensuring the harmony with the building; by considering the form / size, color / pattern properties and achive completeness and integrity,

6. Ensuring the reliability of the system

• Good quality of infrastructure and the installations and correlation with the construction

• Technically and technologically meeting the all quality and quantity needs.