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The “designPH” plugin has been developed by PHI to provide a 3D model interface for entering building geometry into PHPP. The benefits of the tool are two-fold; firstly it will simplify the process of entering data into PHPP and secondly it will provide preliminary feedback on the performance of the design within Sketchup.
The model geometry is marked-up with thermal properties, with the aid of some automatic analysis functions. The tool uses an heuristic algorithm to infer element types, temperature zones and area groups, in order to save input time, but these can be overwritten by the user if required. The external heat loss areas and treated floor area are collected and formatted for export to PHPP. Each window is analysed to identify external shading objects and these are exported as input parameters for each of the three key shading types in PHPP (reveal, overhang and horizontal object).
The export function saves model data to a PPP file, the interchange format developed by PHI, which can then be imported into a PHPP model. Through this process, a 3D digital model can easily be converted to a PHPP workbook. After importing a model, the primary data on the Areas, Windows & Shading sheets will be mostly complete, enabling a result for specific space heat demand to be calculated quickly, without the need for much direct data-entry. The advantages of this approach over entering the geometry directly into PHPP are, firstly that it should save time on data-entry and secondly that it is possible to visually verify in the 3D model that all the heat-loss surfaces have been correctly taken into account.
An additional feature of the tool is that a simplified energy balance will be provided within the 3D modelling environment. This facilitates a more effective iterative design process, allowing the user to get an immediate idea of the building’s energy performance, and rule out poorly performing design options, before exporting to PHPP to fine-tune the design and make the verification.
The user interface provides access to the functions of the tool via the standard Sketchup application menus, context menus and graphical toolbars. The details of the model geometry and energy balance calculations can be interrogated using the web-dialog windows provided. These also allow the components library and other model properties to be edited.
[Edwards 2013] Conference proceedings 2013 - 17th International Passive House Conference