Integrated Parametric Model
The three civil systems: Building Automation System (BAS), Office Building and Drywall Ceiling were combined into one parametric model (CombinedParametricModel-Dynamo). To integrate the different models, it was appropriate to choose the office building as the main system and to equip it with a BAS and suspended drywall ceilings.
The aim in developing the integrated parametric model was to connect the different systems and enable interactions between them. In addition, it was focused on creating an office building model that takes into account energy efficiency and provides daylight-harvesting strategies. To achieve these goals, the following parameters were included to influence the integrated parametric model:
Alternatives
To evaluate the performance of the office building design, the following analysis were performed:
First analysis – Reducing number of windows and increasing extension of brise-soleils
The ideal lighting level of an office building is in the range of 300-500 lux. In order not to fall below or exceed this range, it is important to install the right number of windows on the exterior facades of the office building. In the following examples, the focus is on the windows on the south and east facades of the office building. To bring the value as close as possible to the ideal range of 300-500 lux, the number of windows was reduced and the extension of their brise-soleils were increased, as a result a change in lighting level was observed. Comparing example 1 and example 2, it can be seen that after reducing the number of windows and raising the extension of the brise-soleils, the same overall lux level was maintained. This ideally allows us to plan the required number of windows and the brise-soleils.
Example 1:
Example 2:
3D visualization of example 2:
Second analysis – Optimizing the number of artificial lighting
Next, the amount of artificial lighting in the office building was modified to keep the lighting level as close to 300-500 lux as possible. At first the light fixtures quantity was determined based on the slots available for their positioning on the channel frame for the drywall ceilings (i.e. aligned in their center). This procedure was necessary to avoid cutting and reinforcing the ceiling frame, and to improve access to the plenum and the maintainability of services. Since Revit does not perform artificial lighting analysis to investigate the output lighting level per room, a Python script was developed according to the defined lighting quantity, lumens for the selected lighting fixture and room’s area, and the resulting lighting level in lux was assessed in an excel file. The amount of artificial lighting was then optimized based on the output lighting level displayed in the file.
Example 1:
Example 2:
3D visualization of example 2:
Third analysis – BAS curtain control
Another way to increase the energy efficiency and improve lighting of the office building is to use automatic curtains for windows. The BAS is able to automatically open and close the curtains of the windows depending on the angle of inclination of the sun, saving energy costs and consumption. In addition, this function provides optimal use of daylight, enables glare and solar gain mitigation and improvement of user satisfaction. The following examples show the operating principle of the curtain control. Example 1 shows that at 7:30 a.m. the curtains are fully open, while example 2 shows that at 12 p.m. the curtains are half closed due to the midday sun.
Example 1:
Example 2:
3D visualization of example 2:
Fourth analysis – A/V ratio and quantity of materials
In order to be able to evaluate the energy efficiency, the A/V ratio, which describes the ratio between the surface area (A) and the volume (V) of a building in 1/m, is included. It is used as a reference point to evaluate the compactness of the office building to realize an efficient and sustainable construction project. The A/V ratio is used as a basis for energy efficiency considerations as well as thermal insulation calculations. It is aimed to achieve a small A/V ratio, because this will lower the transmission heat losses. With regard to an office building, an A/V ratio < 0.45 1/m is ideal.
Furthermore, to obtain an approach for the material demand and the possible material costs, the quantity of materials can be determined with the created parametric model as well. For this purpose, the focus was placed on the weight of the columns, which is calculated by the column volume, total number of columns and specific weight of the used material. The columns used in the model are reinforced concrete columns with a specific weight of 2.500 kg/m3.
The following table shows the effect on the A/V ratio and the quantity of materials after influencing the office building dimension:
Example 1:
Example 2:
3D visualization of example 2: