{"id":11861,"date":"2023-02-07T05:27:30","date_gmt":"2023-02-07T05:27:30","guid":{"rendered":"http:\/\/141.23.68.248\/wp\/?page_id=11861"},"modified":"2023-02-12T13:54:50","modified_gmt":"2023-02-12T13:54:50","slug":"prefabricated-facade-panel-parametric-modelling","status":"publish","type":"page","link":"http:\/\/141.23.68.248\/wp\/?page_id=11861","title":{"rendered":"Prefabricated Facade Panel: Parametric Modelling"},"content":{"rendered":"

Abstract<\/b><\/h3>\n

Energetic retrofit solutions for the existing building stock will get more important in the next few years. To give a first support for the design process of a facade panel, this study is about creating a parametric model based on the ontology developed in the further project. It has been aimed to have strong control about the design parameters to give diverse alternatives with different results. To evaluate the model, two high performance criteria are defined: a low heat transfer coefficient\u00a0U<\/i>\u00a0to contain the loss of energy and a weight of the element\u00a0m<\/i>ges<\/i>\u00a0designed to be as low as possible. According to the selected high performance criteria the results are shown and compared.<\/p>\n

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1. Scope and high performance criteria<\/b><\/h3>\n

According to the ontology-prefabricated-fasade<\/a>, this study is about the development of a parametric design model of a prefabricated fa\u00e7ade panel for the energetical retrofit of an old apartment building placed in Germany. For the retrofit solution the focus of the parametric model is on the dimensioning of the new, prefabricated fa\u00e7ade panel.\u00a0The facade panel is timber based with adaptive insulation layer, inner and outer paneling as well as timber frame and inner insulation \u2013 like explained in [1]. The materials used are\u00a0XPS 035<\/i>\u00a0insulation [6],\u00a0OSB\/3<\/i>\u00a0[7], finger joint solid construction timber [8],\u00a0STEICOflex 036<\/i>\u00a0insulation [9] and cement bonded particleboard [10]. Of course if the materials are changed, the results will differ.<\/p>\n

An important factor for this is to enhance the heat transfer coefficient\u00a0U<\/i>, defined as the \u201cheat flow rate divided by temperature difference between two environments\u201d [2]. Because of the importance of this influence factor, it is chosen as the first high performance criterion. The second high performance criterion is the total mass of the facade. Existing buildings mostly have poor masonry or concrete walls, where the panel has to be anchored. The facade has to be as light as possible.<\/p>\n

\"u-value\"<\/a>
\"m_ges\" Figure 1: high performance criteria<\/figcaption><\/figure>\n

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2. Developing a parametric model<\/b><\/b><\/h3>\n

For the development of the parametric-model-prefabricated-facade<\/a>\u00a0Dynamo Revit 2.10 had been used. The workflow is shown in Figure 1. In the first part, the design parameters were summarized. Steps 2-8 show the creation of a simple building and the implementation of the prefabricated facade element. Starting from the building block, the fa\u00e7ade element was created layer by layer – starting with the additional insulation layer, continuing with the planking and the timber frame construction with inner insulation layer. The suggestion of two windows were also included in the fa\u00e7ade module.<\/p>\n

Since the different thicknesses of the individual layers are decisive for the results of the high performance criteria, it is important to always have good control over the changes. That\u2019s why every input parameter is placed in Part 1. The total thickness of the fa\u00e7ade structure as well as the two high performance criteria\u00a0U<\/i>\u00a0and\u00a0m<\/i>ges<\/i>\u00a0were calculated completely in Dynamo. If one of the design parameters is changed, the results also change.<\/p>\n

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\"dynamo-logic\"<\/a>
Figure\u00a02: Dynamo Workflow, 1: design parameter, 2: generate building, 3: windows, 4: adaptive layer (XPS 035), 5: inner panelling layer (OSB\/3), 6: wood frame construction, 7: wood frame insulation (STEICOflex 036), 8: outer panelling layer (cement bonded particleboard), 9: calculation of performance results<\/figcaption><\/figure>\n

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3. Results and Discussion<\/b><\/h3>\n

The three design alternatives\u00a0are shown in Figure 3. The first option shows the strongest wall construction with\u00a00.456 m<\/i>, divided into\u00a00.20 m<\/i>\u00a0adaptive insulation,\u00a00.018 m<\/i>\u00a0OSB\/3,\u00a00.22 m<\/i>\u00a0wood frame and\u00a00.018 m<\/i>\u00a0cement bonded particleboard. Due to the two large insulation levels,\u00a0U<\/i>\u00a0= 0.12 W\/(m<\/i>2<\/i>K)<\/i>\u00a0is the best compared to the other options. Because of the high thickness, the option 1 shows a total mass of\u00a0m<\/i>ges<\/i>\u00a0= 1184.30 kg<\/i>. As a counterpart, alternative 2 shows the lowest thickness with\u00a00.244 m,\u00a0<\/i>which is divided into\u00a00.10 m<\/i>\u00a0adaptive insulation,\u00a00.012 m<\/i>OSB\/3,\u00a00.12 m<\/i>\u00a0wood frame and\u00a00.012 m<\/i>\u00a0cement board. Due to the very narrow wall construction and the resulting low insulation thickness, the heat transfer coefficient is\u00a0U<\/i>\u00a0= 0.23 W\/(m<\/i>2<\/i>K)<\/i>, which is above the limit value (0.20 W\/(m<\/i>2<\/i>K)<\/i>) for subsidized energy-efficient refurbishment in Germany, which was mentioned in Chapter 1. Compared to option 1, only the thickness of the additional insulation layer was reduced to the minimum, all other layers remain at their maximum thickness \u2013 which means\u00a00.10 m<\/i>\u00a0adaptive insulation,\u00a00.018 m<\/i>\u00a0OSB\/3,\u00a00.22 m<\/i>\u00a0wood frame and\u00a00.018 m<\/i>\u00a0cement bonded particleboard. Although this means that the total wall thickness remains at a relatively high value of\u00a00.356 m.<\/i>\u00a0As result of that the total mass\u00a0m<\/i>ges<\/i>\u00a0= 996.38 kg<\/i>\u00a0is higher than option 2, but lower than option 1. Despite the reduction of the first insulation layer, the value of the heat transfer coefficient\u00a0U = 0.13 W\/(m<\/i>2<\/i>K)<\/i>\u00a0remains close to option 1.<\/p>\n

Since this is an energy-related renovation measure, where the high performance criteria are aimed at a low\u00a0U<\/i>\u00a0and a low\u00a0m<\/i>ges<\/i>\u00a0, design alternative 3 is the best option out of this three options.<\/p>\n

\"Figure<\/a>
Figure 3: three different design alternatives<\/figcaption><\/figure>\n

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